An image processor includes a signal acquiring unit, a first converting unit, a signal specifying unit and a second converting unit. The signal acquiring unit acquires a signal in a color space having a perceptual property. The first converting unit converts the signal acquired by the signal acquiring unit into a first color signal in a color-mapping space having an equilightness-equihue plane. The signal specifying unit specifies a second color signal in the color-mapping color space corresponding to the first color signal, as a color-gamut mapping process. The second converting unit converts the second color signal specified by the signal specifying unit into a signal in a same color space as the color space to which the signal acquired by the signal acquiring unit belongs.

1. Technical Field
The invention relates to an image processor, an image processing program, a computer readable medium storing the image processing program, an image processing method, a computer data signal embedded with the image processing program for performing a color-gamut mapping process to determine a corresponding reproduction color and for evaluating the reproduction color.
2. Related Art
In recent years, various devices have been in widespread use as a device for treating a color image. However, in the case of treating the same image data with different devices, in order to match device color spaces to each other, a color conversion process, particularly, a color-gamut mapping process is required. For example, a device such as a display monitor and a digital camera uses a device color space represented by RGB while a device such as a printer and a copier uses a device color space represented by YMCK.
In the case of matching the device color spaces to each other, although a color tristimulus value XYZ or a color stimulus specification LMS provided by CIE (International Commission Illumination) can be used as a color space for this process, it is general that any one of a CIELAB space and a CIECAM space (for example, any of JCh or Jacbc) is used. In other words, there are two mechanisms as the general color-gamut mapping process. The former that uses the CIELAB (D50) space is a mechanism adopted by ICC (International Color Consortium) and has been widely spread. The latter that uses the CIECAM space is a mechanism suggested by CIE in order to solve some problems of the former.

Image processor, computer readable medium storing image processing program, and image processing method


A hard drive vitrectomy cutter generally includes a hand held probe for cutting tissue of a body, and a mechanical system for driving cutting action of the probe. The probe includes an outer sleeve having a perforation therein for receiving a portion of tissue, and a cutter sleeve, coaxially disposed within the cutter sleeve, for shearing the portion from the body of tissue. Importantly, the mechanical system for driving the probe includes a coaxial cable having a stationary outer cable and a slidable inner cable, said coaxial cable being connected with a stepper motor adapted for moving the inner cable axially within the outer cable. The inner cable is mounted in operative relationship with the cutter sleeve such that the stepper motor may be operated to move the inner cable and consequently drive cutting strokes of the cutter sleeve. A spring may be included for biasing the cutter sleeve against a pulling force exerted by the stepper motor. An aspiration line may also be included for pulling the portion of tissue into the perforation and subsequently removing the sheared portion from the probe.

The present invention generally relates to surgical instruments and more particularly relates to a tissue cutting surgical device suitable for use in vitreous and retinal surgery.
An eye surgery procedure performed behind the lens is called vitreous surgery in as much as the posterior chamber of the eye is filled with a transparent jelly called the vitreous humor (xe2x80x9cvitreousxe2x80x9d).
Understandably, vitreous surgery, as with any ophthalmic surgical procedure, requires great precision. The vitreous is filled with numerous fiber like materials, some of which are attached to the delicate retina. The presence of these fibers make vitreous surgery quite difficult, due to the possibility of retinal injury occurring if one of these fibers is inadvertently severed.
Moreover, retinal surgery, which involves actual cutting of the retina of the eye, must be performed with even greater precision, as the retina is the immediate instrument of vision and is directly connected with the brain by the optic nerve. Thus, a surgical instrument suitable for use in vitreous surgery may not be suitable for use in retinal surgery.
For example, the state of the art vitreous cutter comprises a hand held probe having a cutting tip thereon.
The cutting tip comprises an outer tube having a perforation therein, and an inner tube having a reciprocating cutting edge for shearing portions of tissue drawn into the outer tube perforation. The inner tube is typically driven in an axially reciprocating fashion, at a cutting rate of about 400 strokes per minute, by pneumatic means. More particularly, the pneumatic means typically includes a pressurized air source which supplies periodic bursts of air that drive the inner tube forward within the outer tube. A diaphragm or spring is included in the probe which biases the inner cutting tube backward to a home position. Thus, the cutting strokes of the inner tube are controlled by periodic bursts of air forcing the inner cutting tube forward, alternating with the discontinuing thereof such that the biased spring forces the cutting tube backward.
It well known that such pneumatically driven devices do not operate effectively at very low speeds and are designed for operation at high speeds, for example, hundreds of cycles per minute. Moreover, although the cutting rate provided by such instruments may be controllable to some extent, control over speed and length of an individual cutting stroke is not obtainable. Thus, such cutters may be inappropriate for use in retinal surgery, which requires exceptional precision and control in order to avoid serious injury to the patient.
The present invention provides a ophthalmic surgical cutting instrument that can be operated at very low speeds in order to provide to superior control of cuts made thereby. The instrument in accordance with the present invention may also be operated quite effectively at high speeds when the nature of the surgery so requires.
Accordingly, a surgical cutting device in accordance with the present invention generally comprises a probe having a cutting tip comprised of an outer sleeve and an inner cutter sleeve. This type of cutting tip, as will now be generally described, is presently well known in the art. More specifically, the outer sleeve includes a perforation proximate a distal end of the outer sleeve which provides means for receiving a portion of tissue to be incised. The cutter sleeve is slidably and coaxially disposed in the outer sleeve and includes a cutting edge at a distal end thereof. When the probe tip is urged against a portion of tissue, such as a portion of the vitreous humor, the portion will protrude through the perforation in the outer sleeve and be sheared by a axially reciprocating motion of the cutter sleeve.
Importantly, the present invention also comprises mechanical means for driving the stroking motion of the cutter sleeve at a selected stroke rate of down to about one stroke per minute, or in other words, at an exceptionally slow speed. The mechanical means, which will be described in greater detail hereinafter, enable a physician to control amount and speed of individual strokes of the stroking motion. Moreover, the present invention enables a physician to achieve even a fraction of a cut, if so desired.
More particularly, the mechanical means includes a coaxial cable as means for connecting the probe to a motor adapted for moving the cutter sleeve in an incremental or stroking motion, for example a stepper motor. The cable may comprise an outer stationary cable and an inner cable slidably disposed therein and mounted in operative relationship with the cutter sleeve. A spring may be included within the probe for biasing the cutter sleeve in a home position. Thus, the inner cable and reciprocating cutter sleeve are moved back and forth by alternating forces exerted by the stepper motor and the spring.
An aspiration line, in fluid communication with a bore in the cutter sleeve, may also be provided. More particularly, the aspiration line may be connected to a vacuum source, and may provide means for both gently drawing the portion of tissue into the outer tube perforation and subsequently removing the portion of tissue from the probe to a collection vessel after the cutter sleeve has severed said portion as described hereinabove.
By selection of an appropriate stepper motor, the cutter sleeve may be driven at a selected stroking rate of between about one and about one thousand or more cuts per minute.


A time division multiplex (TDM)/wavelength division multiple access (WDMA) passive optical network (PON) device includes a base station terminal, a wavelength splitter, and a subscriber terminal optical transceiver. The base station terminal includes a transmitter, an optical circulator transmitting the optical signals output from the transmitter to an optical distribution network, and a receiver demultiplexing wavelength division multiplexed upstream signals from the optical distribution network through the optical circulator. The wavelength splitter splits the downstream signals from the base station terminal to subscriber ports corresponding to wavelengths and multiplexes the optical signals received from each of the subscriber ports to the base station terminal. The subscriber terminal optical transceiver receives the downstream signals from the wavelength splitter and reuses the received downstream signals as optical sources for upstream signals.

1. Field of the Invention
The present invention relates to a passive optical network (PON) device for signal transmission between an optical line terminal (OLT) of a telephone office or a base station terminal and an optical network terminal (ONT) or an optical network unit (ONU) of a subscriber terminal in an optical subscriber network, and more particularly, to a time division multiplex (TDM)/wavelength division multiple access (WDMA) PON device in which data to be transmitted to each subscriber is multiplexed using a TDM scheme for transmission for downstream signals destined for an ONT/ONU from an OLT and signals to be transmitted from each subscriber are separately transmitted using a WDMA scheme for upstream signals destined for an OLT from an ONT/ONU.
2. Description of the Related Art
FIG. 1 is a block diagram illustrating a conventional passive optical network (PON). As illustrated in FIG. 1, in the conventional PON, an optical line terminal (OLT) 110 located in a telephone office or in a base station or a housing complex transmits a broadcast signal, a data communication signal, and a voice call signal to a subscriber over a single optical fiber. The signals sent through the single optical fiber are split by an optical splitter 120 through optical fibers connected to subscribers and are delivered to 16, 32, 64, or 128 ONTs 130 or ONUs or more. The ONT 130 or ONU converts an optical signal delivered to a subscriber terminal into an electrical signal, selects a signal dedicated_to the ONT 130 among transmitted signals, and then transmits the separated signal to the subscriber device. For signal transmission to subscribers, the PON uses a time division multiplex (TDM) scheme or a wavelength division multiplex (WDM) scheme. The TDM scheme transmits signals in different time slots for each subscribers. The WDM scheme transmits signals using different wavelengths for each subscribers.
FIG. 2 is a block diagram illustrating a conventional TDM PON. As illustrated in FIG. 2, the conventional TDM PON uses a TDM scheme in which a time division multiplexer 210 converts a plurality of downstream signals destined for subscribers into a high-speed single signal, an optical transmitter 220 modulates the converted signal into a single optical signal for transmission to the subscribers, and once the optical signal is transmitted to all the subscribers by an optical power splitter 240, each of the subscribers converts the optical signal input to an ONT into an electrical signal by using an own optical transceiver 250 and selects and receives only a downstream signal corresponding to the subscriber. For each upstream signal coming from each subscriber, a time division multiple access (TDMA) scheme is used in which the optical transceiver 250 of the subscriber transmits a signal within a time slot allocated to the subscriber to arrange the upstream signal at a corresponding point of time.
The TDM PON has been implemented using various methods such as ATM-PON, BPON, GPON, and EPON. At present, technologies capable of 1 Gb/s transmission are commonly used and PONs capable of 10 Gb/s transmission are under standardization.
In the TDM scheme, an OLT can reduce production costs compared to a wavelength division multiplex (WDM) scheme by exchanging a signal with all subscribers using the single optical transmitter 220 and an optical receiver 230. In other words, while a base station terminal requires N optical transceivers 250 for N subscribers in the WDM scheme, a base station terminal requires only one optical transmitter 220 and only one optical receiver 230 in the TDM scheme. Moreover, a broadcast or multicast signal destined for all subscribers can be transmitted to all the subscribers through a single packet in the TDM scheme. However, a transmission band is reduced because subscribers share upstream/downstream transmission bands of the optical transmitter 220 and the optical receiver 230, and a complex circuit is required for the optical receiver 230 for an upstream signal because the OLT has to receive packets of different amplitudes and phases in a burst mode format from different subscribers.
FIG. 3 is a block diagram illustrating a conventional WDM PON. As illustrated in FIG. 3, the conventional WDM PON uses, for downstream signals destined for subscribers, the WDM scheme in which the downstream signals are converted into optical signals using optical transmitters 310 which respectively have different wavelengths, the optical signals which respectively have different wavelengths are input to a single optical fiber by a wavelength division multiplexer 320 for transmission to the subscribers, a signal for each of the subscribers is separated using a wavelength splitter 340. The conventional WDM PON uses, for upstream signals transmitted from subscribers, the wavelength division multiple access (WDMA) scheme in which the upstream signals are transmitted to an OLT using optical transceivers 350 which respectively have different wavelengths.
The wavelength splitter 340 functions for downstream signals as a wavelength division demultiplexer which outputs optical signals of a plurality of wavelengths input through a port connected to the OLT to a port connected to each subscriber for each wavelength and functions for upstream signals as a wavelength division multiplexer which multiplexes an optical signal input through a port connected to each subscriber and outputs the multiplexed optical signal to a single port for transmission to the OLT.
A WDM PON is capable of 100 Mb/s-level transmission per wavelength at its early stage, and now has an increased transmission speed of up to 1 Gb/s per wavelength. Although the WDM PON may use different wavelengths for an upstream signal and a downstream signal for each subscriber, a remodulation scheme for generating an upstream optical signal by re-using a downstream optical signal as an optical source is also used as an approach for reducing costs by reducing the number of optical sources. As an example of the remodulation scheme, a method of remodulating a downstream optical signal modulated at a high speed of 10 Gbit/s to generate an upstream optical signal modulated at a low speed of 1 Gbit/s is used in the paper titled "Demonstration of Data Remodulation for Upstream Traffic in WDM Access Networks Using Injection-Locked FP Laser as Modulator" published by L. Y. Chan, et. al, in the Optical Fiber Communication Conference and Exhibit in 2001.
According to the WDM scheme, a subscriber can transmit a signal up to the transmission bands of the optical transmitter 310 and of an optical receiver 360 of the OLT because the optical transmitter 310 and the optical receiver 360 are allocated to each subscriber at a base station terminal. Furthermore, a circuit of the optical receiver 360 for an upstream signal is simplified because a packet transmitted from each subscriber to the OLT is in a continuous mode format. However, production costs increase because the numbers of optical transmitters 310 and optical receivers 360 of the OLT are the same as the number of subscribers, and the OLT has to repetitively transmit a downstream signal such as a broadcast signal at the same time to the subscribers because an optical splitter cannot perform transmission in a broadcast or multicast manner.

Electronics and Telecommunications Research Institute


The present invention provides a dye-containing negative curable composition comprising at least two dyes (A), an oxime photopolymerization initiator (B) and a radical polymerizable monomer (C); or a dye-containing negative curable composition comprising at east two organic-solvent soluble dyes (A), an oxime photopolymerization initiator (B), a radical polymerizable monomer (C) and an organic solvent (D), wherein the moisture content of the composition is less than 1% by mass relative to the total amount of the composition.

1. Field of the Invention
The present invention relates to a dye-containing negative curable composition suitable for forming a color filter used for liquid crystal display devices and solid-state image pickup devices, a dye-containing color filter and a method for producing the same.
2. Related Art
Known methods for producing a color filter used for liquid crystal display devices (LCD) and solid state image pick-up devices (CCD, CMOS, etc.) include a dying method, printing method, electrodeposition method and pigment dispersion method.
Of these methods, the pigment dispersion method is a method for producing the color filter by a photolithographic method using a colored radiation-sensitive composition in which a pigment is dispersed in various photosensitive compositions. Since a pigment is used as a colorant, the method is advantageous in stability against light and heat. In addition, positional accuracy is high since the filter is patterned by the photolithographic method, and the method has been widely used for favorably producing a color filter for highly precise color displays having a large screen size.
When the color filter is produced by the pigment dispersion method, a coating film is formed by applying a radiation sensitive composition with a spin coater or roll coater followed by drying on glass substrate, colored pixels are formed by patterned exposure and development of the coating film, and the color filter is obtained by repeating this procedure for each color depending on the number of hues. Known examples of such pigment dispersion method include using a negative photosensitive composition in which a photopolymerizable monomer and a photopolymerization initiator are used together in an alkali-soluble resin (for example, see Japanese Patent Application Laid-Open (JP-A) Nos. 2-199403, 4-76062, 5-273411, 6-184482 and 7-140654).
On the other hand, the color filter for the solid state image pickup device has been required to be further fine and precise. However, it is difficult to attempt to further improve resolution in the conventional pigment dispersion system, since color unevenness tends to appear due to a relatively coarse particle diameter of the pigment. Accordingly, the pigment dispersion method has not been suitable for the uses such as the solid state image pick-up device (CCD) in which fine patters are required.
In view of the above-mentioned problems, a method using a dye in place of the pigment has been proposed as a solving method (for example, see JP-A No. 2005-99488).
In view of the above-mentioned problems, a technique using an organic solvent-soluble dye (may be simply referred to the "dye" hereinafter) in place of the pigment has been proposed as another solving method (for example, see JP-A No. 2005-99488).
In another technique for producing the colored photosensitive resin composition containing a dye, the moisture content in the composition is restricted within a specified range in order to suppress minute patterns after development from being peeled and to suppress incidence of penetration of the patterns into the substrate form appearing (for example, see JP-A No. 2003-29542).
The composition containing the dye is usually poor in light resistance as compared with the composition containing the pigment. For improving light resistance, an alcohol-soluble Ni or Co compound or a transition metal complex is added in vitreous colored filters (see, for example, Japanese Patent No. 2986796, and JP-A Nos. 11-223720 and 2004-295116).

Dye-containing negative curable composition, color filter and method for producing the same


This invention relates to a two-piece grommet adapted for holding a cable in an aperture, such as in a desk or work surface so as to absorb any strain imposed on the cable and to provide an attractive covering for the hole drilled to pass the cable. The grommet consists of two portions. The first portion comprises a cylindrical sleeve having a circular lip. The second portion comprises a cap having an extended flange and adapted to frictionally fit into the cylindrical sleeve and against the lip. The cap has an aperture cut into it through which the cable passes. A pivotal tab is connected under the cap to close the aperture when no cable passes therethrough.

Devices for passing a flexible or non-flexible cord, such as a telephone cord or computer cable, through one or more elements such as a desk top, a piece of furniture, a wall or other type of installation are well known. Various devices to do this are known in the art and each of these devices has drawbacks. One device, which is now being used, requires a spring loaded cap which is held in place within a sleeve by the action of the spring. This device is complex, expensive and difficult to use. Other devices consist simply of a cylindrical sleeve in which the hole in the panel or desk must be cut to precisely the exact site or the sleeve will simply fall out, particularly if it is set in a vertical position. If the hole is not cut to the precise size, means must be used to secure the sleeve into the hole.

This patent is subject to a terminal disclaimer.

Wire management grommet with non-captive closure member and sleeve


The present invention is embodied in a barcode system that includes an encoder configured to create a two-dimensional color barcode representing data defined by a first data layer and a second data layer, wherein the first data layer is preserved and the second data layer is lost during black and white copying of the color barcode.

Early barcodes were typically one-dimensional ("1-D") barcodes containing a series of vertical black lines separated by white spaces which contained information readable by handheld or other types of scanners. The amount of information which could be recorded by a 1-D barcode in a given area was limited. This led to the development of black and white two-dimensional ("2-D") barcodes, which were often just a series of stacked 1-D barcodes still constrained as to the amount of data they could carry. To carry more data, color 2-D barcodes were developed. While 2-D color barcodes carry a greater amount of information than traditional black and white 2-D barcodes, when photocopied using a traditional black and white copy process, the 2-D color barcodes exhibit unknown loss characteristics which destroy the data information originally stored in the 2-D color barcode.

Two-dimensional color barcode with preserved plane and lossy plane layers

Hewlett-Packard Development Company, L.P.


A present novel and non-trivial system, device, and method for generating a route image presentable on a display unit is disclosed, where a route may be presented to draw a viewer's attention to one or more objects located along or below the route. An image generator (“IG”) may be configured to receive navigation data; receive object data; construct one or more raised ground track profiles as a function of the first elevations and one or more object clearance distances; identify, if any, one or more penetrated segments of one or more raised ground track profiles; and generate an image data set representative of an image of a divisible route configured to present a plurality of route section highlighters comprised of one or more first route section highlighters corresponding to non-penetrated segment(s) and at least one second or subsequent route section highlighters corresponding to first or subsequent penetrated segment(s), respectively.

1. Field of the Invention
This invention pertains generally to the field of display systems such as, but not limited to, aircraft display systems.
2. Description of the Related Art
The United States Federal Aviation Administration ("FAA") has published a Technical Standard Order ("TSO") identified as TSO-151c in which minimum performance standards of a Terrain Awareness and Warning System ("TAWS") are specified. TSO-151c defines standards of alert conditions corresponding to forward looking terrain avoidance ("FLTA") functions, a premature descent alert ("PDA") function, and a plurality of ground proximity functions. For each of these functions, visual and aural alerts are required if specific conditions stated in the TSO-151c are met. For visual alerts, amber and red text messages are required for caution and warning alerts, respectively. Although text alerts are specified in TSO-151c, there is no requirement to present other forms of visual presentation(s) or to provide useful, graphical general terrain information.
With respect to a flight plan, an image of an aerial pathway that appears on an aircraft display unit is useful and informative to the pilot of an aircraft; for one reason, it provides guidance information within the scene outside the aircraft, thereby enhancing a pilot's situational awareness. One image of an aerial pathway is commonly referred to as a highway-in-the-sky ("HITS"), the generation and employment of which are known to those skilled in the art. An aerial pathway comprised of an abbreviated pathway has been disclosed by Chiew et al in U.S. Pat. No. 7,965,202 ("the Chiew reference"), where the abbreviated pathway comprised of a series of connected waypoints was shown. Although the HITS pathway and abbreviated pathway disclosed in the Chiew reference provide useful guidance information, it is difficult to discern the ground track underneath the pathway. Moreover, it is difficult to visually discern approaching terrain clearances; that is, the distances between the altitude of the aircraft and the terrain over which it is expected to fly.

Route image generating system, device, and method


The present invention is to provide a terminal insertion apparatus to insert a terminal into a terminal receiving chamber without hitting an inner surface of the terminal receiving chamber. A terminal insertion apparatus includes a housing holder unit, an insertion unit, and a control device. The housing holder unit holds a connector housing and is movable in a horizontal direction and a vertical direction. The insertion unit inserts a terminal attached with an electrical wire into a terminal receiving chamber of the connector housing. The control device controls a move unit support portion to reciprocate a housing holder by a move distance after an end portion of the terminal is inserted into the terminal receiving chamber so that the terminal can be inserted without hitting an inner surface of the terminal receiving chamber.

1. Field of the Invention
The present invention relates to an apparatus for inserting a terminal connected with an electrical wire into a terminal receiving chamber of a connector housing.
2. Description of the Related Art
A variety of terminal insertion apparatus (for example, JP 2006-92841 A) has been utilized to insert a terminal 103 connected with an electrical wire 102 into a terminal receiving chamber 101 of a connector housing 100 to be assembled into a wiring harness of a motor vehicle.
The terminal insertion apparatus includes a main body, a housing holder, a wire holder, and an insertion head. The main body is installed on a floor of a factory and the housing holder is attached to the main body to hold the connector housing 100. The wire holder holds the electrical wire 102 attached with the terminal 103. The insertion head removes the electrical wire 102 from the wire holder and inserts the terminal 103 into the terminal receiving chamber 101.
The conventional terminal insertion apparatus inserts the terminal 103 in a longitudinal direction of the terminal receiving chamber 101. This insertion causes the terminal 103 to hit a projection 101a disposed on an inner surface of the terminal receiving chamber 101 as shown in FIG. 8. Even in this case, the conventional apparatus attempts to further insert the terminal 103 into the terminal receiving chamber 101. The further insertion inclines the terminal 103 and fails to move the terminal 103 as shown in FIG. 9. In the worst case, the insertion head bends the electrical wire 102 or deforms the terminal 103, resulting in a defective product.


A method and device are provided for processing an input value to provide an output inverse trigonometric function value of the input value. It substantially comprises a method and device for modifying the input value to obtain an approximation value, determining at least one correction factor, generating at least one intermediate function value, being substantially an inverse trigonometric function value of the approximation value, and combining the intermediate function value with at least one correction factor to determine an output inverse trigonometric function value.

Algorithms for computing sine, cosine, and tangent functions have been developed. Volder formulated a CORDIC algorithm to utilize hardware implementation for evaluating trigonometric functions, that algorithm making use of a special sequential arithmetic unit for implementing a prescribed sequence of conditional additions or subtractions for evaluating trigonometric functions.
The CORDIC algorithm was generalized by Walther, in A Unified Algorithm For Elementary Functions, Spring Joint Computer Conference, 1971. The CORDIC algorithm is utilized typically for fixed point arithmetic implementation of sine, cosine, and tangent functions, but generally is more difficult to apply to computation of inverse trigonometric functions. There is a need for fast, efficient determination of inverse trigonometric functions.

Device and method for evaluating inverse trigonometric functions


A land area can be improved to support a geotextile having nonwoven top and bottom layers, and a geogrid core. The top layer defining at least one parking space, such that land areas of various sizes can be covered to form parking lots with rain-draining features.

The transportation industry often requires additional parking areas for temporary vehicle storage prior to vehicle transfer and/or distribution. Such parking areas are typically needed adjacent rail yards and automotive production facilities. These additional parking areas are frequently only needed for a relatively short period of time, such as two or three months. Additional parking areas could instead be intended for semi-permanent (multi-year, though not indefinite-term) use, for reasons including utilizing the property pending sale or further development, or providing parking for a long-term but fixed-end-date project. Hence, it is often desirable to minimize the time and expenses associated with constructing additional parking areas, whether for multi-month or multi-year use.
Traditionally parking lots are constructed by covering a land area with concrete or asphalt. These traditional construction methods provide a desirable hard surface for vehicles to be driven on, but are time-consuming and expensive to provide. Further, covering the land area with concrete or asphalt can create complications in the project, such as having to construct a retention pond to deal with excess rain water, since the surface is not permeable. Finally, even a semi-permanent parking lot is expensive and difficult to remove when made of concrete or asphalt, and removal may leave the underlying ground surface undesirably altered.
Other, less permanent methods for constructing parking lots are also known. These other methods include covering a land area with gravel, wood chips, or shredded rubber from recycled tires. These non-traditional methods reduce the time and expenses associated with constructing the parking areas. However, these methods do not provide the desired parking surface, and can lead to the vehicles being damaged. Such vehicle damage can range from scratches in a vehicle's paint to extensive body damage caused by vehicles sliding into one another when excessive rain washes away the gravel, wood chips, or shredded rubber, and turns at least a portion of the parking area into a mud pit.

Method and apparatus for constructing a parking lot


A method and apparatus for extinguishing fires by simultaneously applying a spray of dry powder and liquid/liquid-foam, including a nozzle for the simultaneous spray of powder and liquid/liquid-foam, wherein the velocity of the powder stream can be adjusted.

The effectiveness of dry powders in extinguishing fires has been known for some time. Sodium bicarbonate, potassium bicarbonate, monophosphate, potassium chloride (Purple K) and potassium salt are some powders that have been used in fire extinction systems. Silicone may be added to the dry powder to aid in the powder's free flow. Even silicone alone has been used effectively as a dry powder to extinguish fires.
A liquid, and more particularly, a liquid foam may be used in conjunction with a dry powder for extinguishing a fire. For the powder to operate effectively in this situation, however, it should be prevented from wetting. Further, if the powder is not well treated with an anti-wetting composition, the powder may break down the foam.
It is known in the art to coat the dry chemicals used as powders to fight fires with silicone or other anti-wetting compositions. It is recommended, in the applications discussed herein, to use "foam compatible" powders as defined by the NFPA. Experience indicates that treated powders can comingle with foam at the site of the fire without inhibiting either product's fire extinguishing properties.
The use of dry powder to extinguish fires has at least two significant disadvantages. Dry powder is difficult to spray for any distance. Thus, the spraying nozzle for dry powder alone must be drawn much closer to the fire than a liquid nozzle. Further, a fire extinguished by powder has a definite propensity to reignite under common circumstances. If a three dimensional fire, in particular, has burned long enough to heat elements in its environment, such as metals, although the dry powder may extinguish the fire, it is likely to reignite when the powder dissipates.
The term two dimensional (or static) fire is used herein to indicate the combustion of a non-replenishing fluid or solid. An example of a two dimensional fire is the burning of a tank or pond that is not, or at least is no longer, being fed from a remote source. The term three dimensional (or dynamic) fire, by distinction, is used to refer to a fire that is fed by a remote replenisbing source. A well blow out and a burning tanker (the burn area being fed by fluid from within) are examples of three dimensional, dynamic fires.
Dry powder is particularly useful in extinguishing a three dimensional fire, subject to the above disadvantages. Liquids and liquid foam mixtures are particularly useful in extinguishing static, two dimensional fires, as well as in cooling and reducing the size of three dimensional fires. It is quite difficult, however, with liquid and liquid foam mixtures alone, to extinguish a three dimensional fire.
The alternating use of powders and liquids on fires has been attempted. The difficulty with this technique is the degree of coordination required and the close approach to the fire required for the powder nozzle.
The present invention discloses a method and apparatus for applying simultaneously dry powder and liquid, including a liquid foam mixture, to a fire. The method and apparatus is particularly useful for the extinction of three dimensional fires, together with their associated static fires. The method and apparatus achieves not only the advantage of permanently extinguishing a three dimensional fire but also the enhanced safety of permitting operation from a greater distance by extending the distance over which dry powder can be effectively sprayed.
The invention further discloses method and apparatus for adjusting the velocity of the powder stream in order to coordinate that velocity with the distance from the fire of the applying mechanism, be it hand held nozzle or monitor. The ability to adjust the velocity of the powder to coordinate with the distance from the fire of the applying mechanism helps to ensure that the powder stream terminates at the fire, rather than shooting through it.
It has been found that use of the present invention has the further advantage that the amount of dry chemical or powder required to extinguish a fire can be reduced drastically, from say 500 pounds to 75 pounds.

Dry powder and liquid method and apparatus for extinguishing fire


A duplexer, usable to interlink a receiver unit, transmitter unit, and an antenna unit of a communication system, has a body that includes cavities and interconnecting apertures. The duplexer further includes resonator covers that cover the cavities and apertures from a bottom side of the body and tuning covers that cover the cavities and apertures from a top side of the body. The resonator covers have integral resonator posts that extend into the cavities when the resonator covers are press-fitted into the body. The tuning covers have threaded openings for the insertion of tuning screws into the cavities and for the insertion of coupling screws into the apertures. The cavities and apertures are tuned to reflect or pass signals of selected frequencies by turning the tuning screws and coupling screws.

In communication systems that employ a common antenna for use with a transmitter unit and a receiver unit, a duplexer interlinks the transmitter unit, the receiver unit, and the common antenna. A typical duplexer is a combination of bandpass and band-reject filters that allow signals from the transmitter to reach the antenna while preventing the transmit signals from reaching the receiver. Similarly, signals received by the antenna travel through the duplexer to the receiver, but are prevented from reaching the transmitter.
A traditional duplexer for use in the 800 MHz and greater range comprises a machined metallic block having a rectangular body with a top side and a base. The body consists of a series of cavities and interconnecting apertures, both of which are tuned to reflect or pass signals at selected frequencies. The cavities and interconnecting apertures are all open to the top side of the body and are closed to the base of the body. Resonator posts, which are an integral part of the body, extend upward from the base of the body. Each resonator post extends upward through the center of a cavity. A rectangular cover, having the same dimensions as the top side of the body, is attached to the top side of the body through the use of a large number of screws.
This prior art duplexer design is expensive and creates several problems. First, the structure of the body requires that each duplexer be machined from a solid block of aluminum, a process which is both labor intensive and costly. Second, the number of screws used to attach the cover to the body increases the parts cost and the labor cost of the duplexer. Finally, securing the wires around the resonator posts typically requires that the entire body of the duplexer be heated because the resonator posts are an integral part of the body. This creates a potential for warping and prevents testing before the entire assembly is complete.
Therefore, there is a need for a duplexer that is less expensive to manufacture, easier to assemble, and capable of being partially tested prior to the assembly of the entire duplexer.


Form a dielectric layer on a semiconductor substrate. Deposit an amorphous Si film or a poly-Si film on the dielectric layer. Then deposit a SiGe amorphous-Ge or polysilicon-Ge thin film theteover. Pattern and etch the SiGe film using a selective etch leaving the SiGe thin film intact in a PFET region and removing the SiGe film exposing the top surface of the Si film in an NFET region. Anneal to drive Ge into the Si film in the PFET region. Deposit a gate electrode layer covering the SiGe film in the PFET region and cover the exposed portion of the Si film in the NFET region. Pattern and etch the gate electrode layer to form gates. Form FET devices with sidewall spacers and source regions and drains regions in the substrate aligned with the gates.

This invention relates to a method of manufacture of MIS (Metal Insulator Semiconductor) and MOS (Metal Oxide Semiconductor) FET (Field Effect Transistor) devices, and more particularly to a method of manufacture of Complementary MIS FET (CMIS) and Complementary MOS FET (CMOS) devices with SiGe gates.
CMIS and CMOS devices include NFET and PFET devices in doped regions in a substrate and counterdoped regions in the substrate respectively. Frequently the region in the substrate in which the PFET devices are formed comprises a counterdoped well in the substrate.
The metal part of a MISFET/MOSFET device is a conductor known as a gate electrode, hereinafter often referred to as gate. The gate electrode is composed of a material such as doped polysilicon or a metal conductor formed above the insulator of the MISFET generally referred to as the gate dielectric layer in a MISFET or gate oxide layer in a MOSFET. The gate electrode is part of a gate electrode stack that includes the gate dielectric layer which is supported on a semiconductor layer or substrate. A channel region is formed in the substrate below the gate dielectric.
A CMIS device or CMOS device includes both NFET (N-channel) devices (with source/drain regions doped with N-type dopant) devices and PFET (P-channel) devices.
A pair of source/drain regions are formed in the substrate juxtaposed with the channel region, generally aligned with the sidewalls of the gate electrode stack. The insulator of such a device is a gate dielectric which separates the gate from the semiconductor substrate upon which the gate dielectric and the gate are formed. In other words, a MIS FET or a MOS FET is a field effect transistor (FET) with a gate formed over an insulator known as a gate dielectric layer which is interposed between a channel region in the semiconductor substrate and the gate. When the gate insulator or gate dielectric insulator of a MISFET is an oxide (typically silicon oxide) the device is known as a Metal Oxide Semiconductor FET (MOSFET) device.
MISFET or MOSFET devices are typically created on the surface of a substrate after either a P-type or a N-type impurity has been implanted in the surface of the substrate, creating wells in this surface of either P-type or N-type conductivity. NMIS or NMOS devices (also referred to as n-channel devices) are, after that, created on the surface of a P-type well. In like manner, PMIS or PMOS devices (also referred to as p-channel devices) are created on the surface of an N-type well.
After the gate has been created, Lightly Doped Drain/Source (LDD/LDS) regions, commonly referred to as LDD regions, are typically implanted in the surface of the substrate, self aligned with the gate, whereby N-type impurities are used for the LDD regions of NMIS/NMOS devices and P-type impurities are used for the LDD regions of PMIS/PMOS devices, which are self aligned with the gates. After this, each of the gates is isolated by the formation of gate spacers on the sidewalls of the gates. This is followed by forming the source and drain regions of the gates which are self aligned with the spacers.
For the source/drain implants the same type impurities are used as have been used for the LDD implants. The difference between the LDD implants and the source/drain implants is that the source/drain implants are typically performed at higher implant energy and dosage that the LDD implants. In this manner the P-type implants (for PMIS/PMOS devices) of the source/drain regions (PS/D) and the n-type implants (for NMIS/NMOS devices) of the source/drain regions (NS/D) penetrate deeper into the surface of the substrate than the corresponding P-type (PLDD) and N-type (NLDD) implants for the LDD regions.
U.S. Pat. No. 6,524,902 of Rhee et al. entitled "Method of Manufacturing CMOS Semiconductor Device" points out that in the fabrication of a CMOS device, boron is doped or implanted into a polysilicon gate layer to form gates of PMOS transistors. The impurity implantation of the p-type doping impurity, e.g. boron, is often carried out along with the formation of the source/drain regions by an ion implantation process. The problem is that where boron is used as a dopant in the impurity implantation, it may diffuse and escape into P-channels through a thin gate insulating layer, unless it is insufficiently planted or activated; and the problem is more serious because the gate insulating layer is very thin. If boron ions escape from the gate in the impurity implantation, boron concentration in the gate near to the gate insulating layer declines and the result is the problem of the Poly-Gate Depletion Effect (PDE). The manufacturing process described by Rhee et al involves blanket deposition of a polysilicon-SiGe layer, followed by formation of additional silicon cap layer formed over the polysilicon SiGe layer. Then phosphorus ions are implanted selectively into an NMOS region, but not into the PMOS region which is covered by an ion implantation mask on the silicon cap layer to cover at least one PMOS transistor region. During a subsequent thermal annealing step, the implanted N-type impurities (phosphorus ions) in the NMOS region enhance diffusion of Ge atoms into the silicon cap layer of the NMOS region, since the annealing step drives Ge atoms in both the downward and upward directions more freely as a result of the ion implantation step. The result is that a desired germanium dopant profile is produced in the SiGe layer and in the silicon layer in the NMOS transistor region, while germanium is substantially prevented from diffusing into the silicon layer in the PMOS transistor region maintaining a high level of Ge near the gate oxide.
The Abstract of an article by E. J. Stewart, M. S. Carroll, and James C. Sturm entitled "Suppression of Boron Penetration in P-Channel MOSFETs Using Polycrystalline Si1-x-yGexCy Gate Layers" in IEEE Electron Device Letters, VOL. 22, NO. 12, (December 2001) 574–576, states that "Boron penetration through thin gate oxides in p-channel MOSFETs with heavily boron-doped gates causes undesirable positive threshold voltage shifts. P-channel MOS-FETs with polycrystalline Si1-x-yGexCy gate layers at the gate-oxide interface show substantially reduced boron penetration and increased threshold voltage stability compared to devices with all poly Si gates or with poly Si1-x-yGex gate layers. Boron accumulates in the poly Si1-X-YGeXCY layers in the gate, with less boron entering the gate oxide and substrate. The boron in the poly Si1-X-YGeXCY appears to be electrically active, providing similar device performance compared to the poly Si or poly Si1-X-YGeXCY gated devices."
E. J. Stewart, M. S. Carroll, and James C. Sturm entitled "Boron Segregation and electrical properties in polycrystalline Si1-X-YCY and Si1-YCY Layers" in Journal of Applied Physics, VOL. 95, Number 8, (15 Apr. 2004) pp. 4029–4035 "reports strong boron segregation to polycrystalline Si1-x-yGexCy from polysilicon during thermal anneals . . . . " The article also states "Conventional p-channel MOSFETs with heavily boron-doped polysilicon gates can suffer from voltage instabilities, caused by diffusion from the gate through the gate oxide and into the channel during post implant anneal. Devices with polycrystalline Si1-X-YGeXCY layers in the gate have less boron penetration, and greater threshold voltage stability than devices with polycrystalline Si or Si1-XGeX gate layers."
U.S. patent application Ser. No. 2004/021743 A1 of Chu entitled "High Performance FET Devices and Methods Therefor" describes a method of fabrication of FET devices in which dopant impurities are prevented from diffusing through the gate insulator. The structure comprises a Si:C, or SiGe:C, layer which is sandwiched between the gate insulator and a layer which is doped with impurities in order to provide a preselected workfunction. The Chu application states that "As the gate insulator is thinned, as dictated by the requirements of ever smaller devices, there is the problem of the doping impurities penetrating the gate insulator, typically an SiO2 layer. For the sake of optimal device design, the gate typically is made of polysilicon, which is doped the same conductivity type as the device itself. With such doping the resultant workfunction of the gate with respect to the channel region of the device allows for the threshold of the device to be optimally set. Accordingly, N-type devices are in need of N-doped gates, and P-type devices are in need of P-doped gates. During the high temperatures of device manufacturing, the gate-doping species, most problematically boron, (B), but others like phosphorus (P) as well, readily penetrates the thin gate insulator and the result is that the gate-doping species destroys the device. The gate insulator in modem high performance devices typically needs to be less than about 3 nm thick. Preventing this dopant penetration would be an important step in achieving thinner gate insulators."
U.S. Patent Publication 2004/0067631 of Bu et al. entitled "Reduction of Seed Layer Roughness for Use in Forming SiGe Gate Electrode" describes how to deposit a "seed" layer to facilitate deposition of a SiGe layer. The method provides for fabricating layers for use in formation of a silicon germanium (SiGe) gate starting with a substrate having a first surface. Then a gate dielectric layer is formed overlying the first surface of the substrate. Next the gate dielectric layer is treated with a gaseous medium to modify a surface characteristic of the gate dielectric. Then, a seed layer is formed overlying the treated gate dielectric thereby mitigating roughness of the seed layer. Then a SiGe layer is formed overlying the seed layer, so that the germanium (Ge) interdiffuses into the seed layer.
U.S. Pat. No. 6,709,912 of Ang et al. entitled "Dual Si-Ge Polysilicon Gate with Different Ge Concentrations for CMOS Device Optimization" describes a method for increasing the amount of Ge over a PMOS region through further implanting and laser annealing. Dual Si-Ge polysilicon gates are formed with different Ge concentrations in the fabrication of an integrated circuit device. An NMOS active area and a PMOS active area of a substrate separated by an isolation region are provided. A gate oxide layer is grown overlying the substrate in both active areas. A polycrystalline silicon-germanium (Si-Ge) layer is deposited overlying the gate oxide layer with the polycrystalline SiGe layer having a first Ge concentration. The NMOS active area is blocked while exposing the PMOS active area and performing successive cycles of Ge plasma doping and laser annealing into the PMOS active area to achieve a second Ge concentration higher than the first Ge concentration. Then, the polycrystalline Si-Ge layer is patterned to form a gate in both active areas. The gate in the PMOS active area has a higher Ge concentration than the gate in the NMOS active area. That completes formation of the dual Si-Ge polysilicon gates with different Ge concentrations in the fabrication of an integrated circuit device.
Referring again to U.S. Pat. No. 6,524,902 of Rhee et al entitled "Method of Manufacturing CMOS Semiconductor Device" the steps of the method are described next. Form a gate insulating layer on a substrate and a SiGe layer having Ge content of more than 20% on the gate insulating layer. Then form a silicon layer on the SiGe layer and form an ion implantation mask on the silicon layer to cover at least one PMOS transistor region. Perform a n-type impurity ion implantation process on at least one NMOS transistor region of the substrate having the ion implantation mask. Perform a diffusion and annealing process on the substrate in which n-type impurities are implanted to diffuse germanium into the silicon layer in the NMOS transistor region to produce a desired germanium dopant profile in the SiGe layer and the silicon layer in the NMOS transistor region, while germanium is substantially prevented from diffusing into the silicon layer in the PMOS transistor region. Then form a gate pattern for PMOS and NMOS transistors by patterning the silicon layer and the SiGe layer. The result of the process is that in the NMOS region where the presence of Ge is unwanted, some SiGe remains present.
In U.S. Pat. No. 6,730,588 of Schinella entitled "Selective deposition of SiGe" a dielectric layer is deposited on a semiconductor wafer. Then a thin silicon layer of amorphous silicon or polycrystalline silicon is deposited on the dielectric layer. A mask is formed over the thin silicon layer, which is used during etching to form a silicon nucleation layer and to expose portions of the dielectric layer. A self-aligned gate is formed by depositing a silicon germanium conducting film on the silicon nucleation layer using a material which selectively deposits on the nucleation layer and which falls to deposit on the exposed portions of the dielectric layer. Then a metal layer is deposited on the top surface of the silicon germanium conducting film. The method employed is very different from that of the present invention.
It is well known that boron activation is superior in poly-SiGe compared to that in polysilicon alone. Thus PFETs with SiGe gates can exhibit a less significant polysilicon depletion effect. The result is that there is a thinner electrical equivalent gate oxide thickness (or inversion thickness), which is beneficial for PFET drive current. In this context, thinner thickness means larger gate capacitance which directly is related to drive current.
However, N type dopant activation in the NFET region may be poorer in the presence of SiGe as evidenced by larger inversion thickness (Tinv) in NFETs with SiGe gates. As employed herein, the term "inversion thickness" (Tinv) is the electrically measured oxide thickness when a MOS device is in inversion. When Tinv is less (thinner) the gate capacitance is greater, leading to a higher drive current.
A serious problem is the "poly depletion effect" which reduces gate capacitance, with the reduced gate capacitance having the disadvantage of reducing device drive current.

Method for forming a SiGe or SiGeC gate selectively in a complementary MIS/MOS FET device

International Business Machines Corporation


A combustor for a gas turbine having a centrally located fuel nozzle and inner, middle and outer concentric cylindrical liners, the inner liner enclosing a primary combustion zone. The combustor has an air inlet that forms two passages for pre-mixing primary fuel and air to be supplied to the primary combustion zone. Each of the pre-mixing passages has a circumferential array of swirl vanes. A plurality of primary fuel tube assemblies extend through both pre-mixing passages, with each primary fuel tube assembly located between a pair of swirl vanes. Each primary fuel tube assembly is comprised of two tubular members. The first member supplies fuel to the first pre-mixing passage, while the second member, which extends through the first member, supplies fuel to the second pre-mixing passage. An annular fuel manifold is divided into first and second chambers by a circumferentially extending baffle. The proximal end of the first member is attached to the manifold itself while the proximal end of the second member is attached to the baffle. The distal end of the first member is attached directly to the second member at around its mid-point. The inlets of the first and second members are in flow communication with the first and second manifold chambers, respectively. Control valves separately regulate the flow of fuel to the two chambers and, therefore, to the two members of the fuel tube assemblies, thereby allowing the flow of fuel to the first and second pre-mixing passages to be separately controlled.

The present invention relates to a combustor for burning fuel in compressed air. More specifically, the present invention relates to a combustor in which fuel is introduced by fuel tubes into two pre-mixing passages.
In a gas turbine, fuel is burned in compressed air, produced by a compressor, in one or more combustors. Traditionally, such combustors had a primary combustion zone in which an approximately stoichiometric mixture of fuel and air was formed and burned in a diffusion type combustion process. Additional air was introduced into the combustor downstream of the primary combustion zone. Although the overall fuel/air ratio was considerably less than stoichiometric, the fuel/air mixture was readily ignited at start-up and good flame stability was achieved over a wide range of firing temperatures due to the locally richer nature of the fuel/air mixture in the primary combustion zone.
Unfortunately, use of such approximately stoichiometric fuel/air mixtures resulted in very high temperatures in the primary combustion zone. Such high temperatures promoted the formation of oxides of nitrogen ("NOx"), considered an atmospheric pollutant. It is known that combustion at lean fuel/air ratios reduces NOx formation. However, achieving such lean mixtures requires that the fuel be widely distributed and very well mixed into the combustion air. This can be accomplished by introducing the fuel into the combustion air in both primary and secondary annular passages so that the fuel and air are pre-mixed prior to their introduction into the combustion zones.
It has been found that mixing of the primary fuel and combustion air is enhanced by using two primary pre-mixing passages. Fuel is introduced into these passages by a number of fuel spray tubes, or "pegs," that extend through the two passages and that are distributed around their circumference. A combustor of this type is shown in U.S. Pat. No. 5,479,782 (Parker et al.), hereby incorporated by reference in its entirety.
Unfortunately, such fuel tubes do not allow the fuel introduced into the two primary pre-mixing passages to be individually regulated. This lack of control prevents optimization of the combustion dynamics.
It is therefore desirable to provide a combustor, such as that suitable for use in a gas turbine, in which the flow of fuel to multiple primary pre-mixing passages can be individually controlled.

Combustor with two stage primary fuel tube with concentric members and flow regulating


A multi-radio equipment arrangement comprises multiple transceivers of different band splits. A preferred arrangement utilizes at least one transceiver for communicating on digital "trunked" RF communications system and at least one transceiver for communicating on a wide-area "conventional" RF communications system. The multi-radio equipment transceivers communicate with each other and with an equipment control unit via a common internal serial data bus to form a multi-radio local network. Each transceiver incorporates a microprocessor controller that includes appropriate task management and serial bus interface software routines for operating and communicating with other devices on the bus. The control unit provides a user interface comprising conventional radio equipment front-panel controls. A "trunked" system transceiver is automatically selected whenever its measured audio quality exceeds a predetermined user-programmable minimum level. When audio quality falls below the predetermined level, an auto-select control task (ASCT) automatically switches to the "conventional" RF transceiver in a manner transparent to the user. Evaluations of the audio quality on each transceiver are assessed on a continuing periodic basic individually by each transceiver and provided to the ASCT. In addition, a radio-roaming feature automatically switches back and forth between two or more "trunked" communications transceivers depending on audio quality available from each trunked system and a preference selected by the mobile user.

Despite continuing beneficial technological advances, radio frequency communications systems will always be constrained within certain physical boundaries by limits on effective transmission range and will always be burdened with effects caused by various geographical and man-made barriers. The present invention specifically addresses these problems by providing the user with an improved multiple radio communications method and apparatus which automatically makes the best use of the equipment and available system resources to insure the highest quality communications at all times.
In both public safety organizations and commercial utility industries mobile radio users often find it necessary to communicate across regionally diverse areas, e.g., state police patrolling a large region of the state may need to remain in contact with city agencies when they are in the vicinity or a fire chief for a local municipality may be called in to support surrounding county agencies. Obviously, many similar situations exist. Different groups or agencies typically use the type of system and equipment that best suits their particular geographical and tactical needs. For example, a large coverage area UHF communications system may be suitable for a state governmental agency whereas a small 900 MHz trunked communications system would be more suitable for a city or municipal agency. Unfortunately, the geographic regions and specific communications needs of each agency or group are often vastly different. So when users of diverse type systems need to communicate to one another, the convenient solution of having them all communicate using the same trunked radio band or using a common conventional radio system is usually not feasible. (For the purpose of the present discussion, a "conventional" radio system--as opposed to a "trunked" system--is defined as frequency modulated (FM) and/or phase-modulated (PM) non-trunking RF communications system).
In the past there were no real solutions to this particular problem. Mobile communications users simply approached the problem by installing and using several different types of RF communications equipment. This resulted in multiple control panels, microphones, and hook switches vying for the typically very limited space available in a mobile environment. Moreover, the added conglomeration of devices still gave the user no insight as to which piece of radio equipment might operate the best at a present location. The user first had to try a radio to know whether or not it would provide satisfactory communications. The only radio known to at least partially address these problems is assignee's own Ericsson-GE ORION.TM. mobile radio, which combines two transceivers with a single control panel interface. This arrangement is known as a multiple radio apparatus or "multi-radio" and although it somewhat reduces equipment clutter it does nothing to help a mobile user know which transceiver is best to use at his current location.
Where a coordinated trunked communications system arrangement between differing agencies and/or commercial entities is not feasible, a lower cost alternative is to install at least one trunked system transceiver along with at least one conventional RF system transceiver in a "multi-radio" mobile equipment arrangement. In this way a mobile user can monitor, for example, a city agency's 800 MHz trunked site and then switch over to a wide area conventional RF system from the same control panel in order to communicate with a county or state agency that employs the wider coverage area system. Although such multi-radio arrangements may enable a user to hear communications on both transceivers, the user can only respond using one transceiver--i.e., the selected radio transceiver. Moreover, the conventional multi-radio systems require one to manually switch between the two transceivers.
Another current problem with mobile radio RF communications equipment is that sine one cannot physically "see" the radio system coverage boundaries, one has no way of knowing when he has reached the coverage limits of a particular communication system. Moreover, even when operating within the boundaries of a particular system there is no way of knowing when the existing transmission/reception conditions are no longer conductive toward providing high quality communications on that system. Even assuming the option to use other equipment or another type of RF communications system existed, a user would still not be able to determine exactly when it would be most advantageous to switch to the different system or if indeed that system would even be able to provide intelligible communications if the switch was made.
As an example, consider the case where a mobile RF communications user usually works within a large coverage region--for this example, a non-trunking "conventional" RF communications system--but also needs to remain in contact with users in a smaller coverage region which is trunked covered by a digital trunked system. In any digital trunked RF communications system, the quality of the transmission drops off as one leaves the primary coverage area. This results in calls that are unintelligible and places where trunked signaling cannot be decoded. Referring to FIG. 1A, a simplified example of primary (101) and marginal (102) coverage areas of a trunked communications system (100) is illustrated. Note that the area of marginal coverage, indicated by hatched region 102, is not necessarily uniform or consistent.
Typically, the audio quality of communications within a trunked communications system is better than that within the wide-area low-band, UHF or VHF conventional (i.e., non-trunked) system, but the geographical coverage area for most 800 MHz and 900 MHz trunked systems is much smaller. Therefore, if considering communications across two separate RF communications systems where one is a trunked system and the other is a non-trunked conventional RF communications system, the two of which have significantly different size coverage areas, it is usually the case that the smaller coverage area trunked system is contained wholly within the larger coverage area system. An example this type of situation is illustrated by FIG. 1B, where a trunked system 100 is shown contained within larger coverage area conventional RF communications system 110. Understandably, while travelling in the marginal coverage area a mobile user would not want to transmit on the trunked system if the audio quality has significantly decreased. However, if and when the signaling quality over the trunked communications system improves, it is usually preferable that the transmission take place on the trunked system.
With present multi-radio equipment, a user deciding to make a call over the trunked system must select the trunked system radio, "key-up" the transceiver, and just hope that one of the trunked system's base station would receive an intelligible signal. Typically, one would not know that the audio quality over the trunked system was bad until one received a call and could hear the quality of the received transmission. To address problems like these, and to solve the problem of trying to select which RF communications system and radio equipment to use when operating an outer perimeter of a system's coverage area (i.e., in the "marginal" area), the method and apparatus of the present invention provides an approach that is both automatic and transparent to the user. Basically, in the improved multi-radio of the present invention, an audio signal quality measurement is automatically obtained for each radio transceiver used in the apparatus and, on a continuing periodic basis, the quality currently obtainable on each transceiver is evaluated taking into account whether the evaluated transceiver is operating within a conventional or a trunked system. A determination is then made as to whether or not communications and control of the multi-radio apparatus should be switched over to a different transceiver.
In accordance with one aspect of the present invention, a multiple radio mobile transceiver apparatus having both a trunked system transceiver and a conventional RF transceiver is provided with a trunked/conventional auto-select capability (also called "E-C Autoset") that automatically selects the trunked system transceiver equipment for use whenever the audio quality on the trunked system is at or above a user-programmable minimum. A quality level preferred minimum is one chosen so as to provide the greatest coverage possible while preventing "ineffective" calls wherein user transmissions are too garbled to understand. The signal quality available on the trunked communications system is evaluated on a periodic basis whether or not a call is in progress. Whenever the signal quality degrades below the preset limit, the present invention automatically switches control to the transceiver equipment that operates using conventional RF communications. Moreover, the switching of control to the different transceiver equipment is accomplished electronically in a manner substantially transparent to the user. Thus, a mobile user is always provided with the ability to transmit (and receive) whether or not the quality of communications using the trunked RF system has degraded or become infeasible--for example, due to the user wandering outside the trunked system coverage area.
In accordance with another aspect of the present invention, a multiple radio mobile transceiver apparatus having at least two trunked system transceivers is provided with an "automatic radio roaming" feature that allows a user to freely roam between two (or more) trunked communications systems and it always selects the particular trunked system transceiver which provides the best audio quality. For example, when a mobile user is traveling near the limit of a coverage area corresponding to one trunked system, this auto-roaming feature of the present invention will cause the multi-radio to apparatus to automatically switch to another (albeit non-selected) trunked system transceiver whenever the measured audio quality on the selected transceiver degrades below a preprogrammed minimum.
Consequently, with the present invention, a mobile user needs no prior knowledge of the geographical coverage areas of the various RF communications systems available with the particular multi-radio apparatus. Moreover, a mobile user's concentration is not hampered by having to focus attention on operation of the radio equipment itself; to wit: switching between different communications systems and trying to determine whether he/she can be heard and understood. Instead, the transceiver selection is automated and overseeing the operation of the multiple radio equipment is greatly simplified. Moreover, for instances where a user would prefer to remain solely on the conventional system, the present invention has a transceiver autoselect disable feature that allows the user to disable the autoselecting of transceiver equipment for either a pre-programmed duration or until the user chooses to manually re-enable the automatic equipment selecting feature. In addition, the present invention also contemplates optional features such as providing the user with an audible indication whenever a "switch-over" to different radio transceiver equipment occurs.

Method for automatic transceiver selection in a mobile multiple RF transceiver apparatus


An image display apparatus is capable of recycling the “OFF” state light to increase the image brightness and contrast. The image display apparatus includes a light source, a spatial light modulator, a total internal reflection (TIR) prism, a projection lens set, and a reflector. The spatial light modulator selectively modulates a light beam from the light source to a first path to form a first path light beam or to a second path to form a second path light beam. The TIR prism disposed between the light source and the spatial light modulator is configured to allow the light beam to travel therethrough in a first direction and to be incident on the spatial light modulator. The projection lens set disposed between the modulator and a screen is configured to project the first path light beam to form an image on a screen. The reflector is configured to reflect the second path light beam to form a reflected light beam that is incident on the TIR prism in a second direction as a recaptured light beam. The recaptured light beam is then incident on the spatial light modulator in the first direction.

Along with the progress of business activities and development of interactive learning, projectors have gradually become indispensable image display apparatuses in many kinds of business events and the image display technology has been advancing from the liquid crystal display to the digital light processing (DLP).
The digital light processing technology employs the reflected light, which is modulated by a spatial light modulator (SLM), such as a commonly-known digital micromirror device (DMD) that has an array of micromirrors. By controlling the tilt angle of each micromirror individually, every micromirror can be selectively arranged in two states, such as an "on" state and an "off" state. Referring to FIG. 1, a block diagram of a conventional image display apparatus is illustrated. When the light beam provided by the light source 10 travels through the integrator 20 and the filter 30 and impinges on the DMD 40, the controller 70 determines, according to image signals, the corresponding state of each micromirror. When an image signal is on, the corresponding micromirror is disposed in the on state, and the light beam is reflected to form an image on a screen 50. When the image signal is off, the corresponding micromirror is disposed in the off state, and the light beam is reflected to other direction and absorbed by the absorber 60 or converted to heat.
Brightness, resolution, weight, and lifetime of the light source are indices for determining the quality of a projector. The brightness, which indicates the intensity of light projected on a screen, especially determines whether a projector can have an effective image in a bright environment. If the brightness achieves some level, the projector can have a projected image in good quality without the need of darkening the environment or turning off the facility's light.
The light source is a component directly relating to the brightness of a projector. In general, a projector displays an image of higher brightness as the light source has greater power (or wattage). However, purely increasing the power of the light source to improve the brightness cannot improve the overall quality of a projector because, for example, a light source of greater power generates more heat, which requires a better heat dissipation mechanism, such as a larger fan. When the fan becomes larger, the noise becomes louder, and the size of the projector increases at the same time. Therefore, increasing the power of the light source to improve the image brightness must sacrifice some quality in other aspects.
Therefore, there is a need to provide an image display apparatus for improving the image brightness without inducing more problems, such as heat.


A seamless steel tube contains 0.15% to 0.50% C, 0.1% to 1.0% Si, 0.3% to 1.0% Mn, 0.015% or less P, 0.005% or less S, 0.01% to 0.1% Al, 0.01% or less N, 0.1% to 1.7% Cr, 0.4% to 1.1% Mo, 0.01% to 0.12% V, 0.01% to 0.08% Nb, and 0.0005% to 0.003% B or further contains 0.03% to 1.0% Cu on a mass basis and has a microstructure which has a composition containing 0.40% or more solute Mo and a tempered martensite phase that is a main phase and which contains prior-austenite grains with a grain size number of 8.5 or more and 0.06% by mass or more of a dispersed M2C-type precipitate with substantially a particulate shape.

In recent years, the following fields have been extensively developed because of soaring crude oil prices and the depletion of oil resources that may occur in the near future: deep oil fields that have not attracted much attention; oil fields in severe corrosion environments such as sour environments containing hydrogen sulfide and the like; and gas fields in such severe corrosion environments. Oil country tubular goods (OCTGs) used in such environments need to have properties such as high strength and excellent corrosion resistance (sour resistance).
To cope with such requirements, for example, Japanese Unexamined Patent Application Publication No. 2007-16291 discloses a low-alloy steel, having excellent resistance to sulfide stress cracking (SSC resistance), for oil well tubes. The low-alloy steel contains 0.20% to 0.35% C, 0.05% to 0.5% Si, 0.05% to 0.6% Mn, 0.8% to 3.0% Mo, 0.05% to 0.25% V, and 0.0001% to 0.005% B on a mass basis and is adjusted such that the inequality 12V+1−Mo≧0 holds. In a technique disclosed in JP '291, when Cr is further contained therein, the contents of Mn and Mo are preferably adjusted depending on the content of Cr such that the inequality Mo−(Mn+Cr)≧0 is satisfied. This allows resistance to sulfide stress cracking (SSC resistance) to be enhanced.
Apart from seamless steel tubes, Japanese Unexamined Patent Application Publication No. 06-235045 discloses an electric resistance welded steel pipe which has excellent resistance to sulfide stress corrosion cracking and which contains 0.05% to 0.35% C, 0.02% to 0.50% Si, 0.30% to 2.00% Mn, 0.0005% to 0.0080% Ca, 0.005% to 0.100% Al, and one or more of 0.1% to 2.0% Mo, 0.01% to 0.15% Nb, 0.05% to 0.30% V, 0.001% to 0.050% Ti, and 0.0003% to 0.0040% B on a mass basis. The contents of S, O, and Ca therein satisfy the inequality 1.0≦(% Ca){1−72(% O)}/1.25(% S)≦2.5 and the contents of Ca and O therein satisfy the inequality (% Ca)/(% O)≦0.55. In a technique disclosed in JP '045, since the addition of Ca leads to an improvement in sour resistance, the content of Ca is adjusted to satisfy the inequality (% Ca)/ (% O)≦0.55, whereby the molecular ratio of (CaO)m.(Al2O3)n, which is a deoxidation product, can be controlled to satisfy the inequality m/n<1; the stretching of complex inclusions in an electrically welded portion is avoided; the production of plate-like inclusions is prevented; and deterioration of SSC resistance due to hydrogen induced blister cracking originating from such plate-like inclusions can be prevented.
Japanese Unexamined Patent Application Publication No. 2000-297344 discloses an oil well steel which has excellent toughness and resistance to sulfide stress corrosion cracking and which is made of a low-alloy steel containing 0.15% to 0.3% C, 0.2% to 1.5% Cr, 0.1% to 1% Mo, 0.05% to 0.3% V, and 0.003% to 0.1% Nb on a mass basis. The sum of the contents of precipitated carbides is 1.5% to 4%. The percentage of the content of an MC-type carbide in the sum of the carbide contents is 5% to 45% and the content of a M23C6-type carbide therein is (200/t) % or less (t (mm) is the thickness of a product). The oil well steel can be produced by performing quenching and tempering at least twice.
Japanese Unexamined Patent Application Publication No. 2000-178682 discloses an oil well steel which has excellent resistance to sulfide stress corrosion cracking and which is made of a low-alloy steel containing 0.2% to 0.35% C, 0.2% to 0.7% Cr, 0.1% to 0.5% Mo, and 0.1% to 0.3% V on a mass basis. The sum of the contents of precipitated carbides is 2% to 5%. The percentage of the content of an MC-type carbide in the sum of the carbide contents is 8% to 40%. The oil well steel can be produced by performing quenching and tempering only.
Japanese Unexamined Patent Application Publication No. 2001-172739 discloses an oil well steel pipe which has excellent resistance to sulfide stress corrosion cracking and which contains 0.15% to 0.30% C, 0.1% to 1.5% Cr, 0.1% to 1.0% Mo, Ca, O (oxygen), and one or more of 0.05% or less Nb, 0.05% or less Zr, and 0.30% or less V, the sum of the contents of Ca and O being 0.008% or less, on a mass basis. Inclusions in steel have a maximum length of 80 μm or less. The number of inclusions with a size of 20 μm or less is 10 or less per 100 mm2. Such an oil well steel pipe can be produced by performing direct quenching and tempering only.
Factors affecting SSC resistance are extremely complicated and therefore conditions for allowing 110-ksi class high-strength steel pipes to stably ensure SSC resistance have not been clear. At present, OCTG (Oil Coutry Tubular Goods) which can be used as oil well pipes in severe corrosion environments and which have excellent SSC resistance cannot be manufactured by any of techniques disclosed in JP '291, JP '344, JP '682 and JP '739. A technique disclosed in JP '045 relates to an electric resistance welded steel pipe in which the corrosion resistance of an electrically welded portion may possibly be problematic in a severe corrosion environment. The steel pipe disclosed in JP '045 is problematic as an oil well pipe used in a severe corrosion environment.
It could therefore be helpful to provide a high-strength seamless steel tube with excellent resistance to sulfide stress cracking (SSC resistance). The term "excellent resistance to sulfide stress cracking (SSC resistance)" means that in the case of performing constant load testing in an aqueous solution (a test temperature of 24° C.), saturated with H2S, containing 0.5% by weight of acetic acid (CH3COOH) and 5.0% by weight of sodium chloride in accordance with regulations specified in NACE TM 0177 Method A, cracking does not occur at an applied stress equal to 85% of the yield strength for a test duration of more than 720 hours.

High-strength seamless steel tube, having excellent resistance to sulfide stress cracking, for oil wells and method for manufacturing the same


An optical-electric composite cable includes an optical fiber, an inner tubular cover enclosing the optical fiber, a plurality of electric wires arranged outside the inner tubular cover, a binding member collectively bundling the plurality of electric wires, and an outer tubular cover covering an outer periphery of the binding member. A gap exists between the binding member and the outer tubular cover.

1. Field of the Invention
The invention relates to an optical-electric composite cable having an optical fiber(s) and plural electric wires.
2. Description of the Related Art
An optical-electric composite cable is known that is used for e.g. signal transmission between electronic devices such as personal computer or display and that an optical fiber and plural electric wires are collectively covered by a sheath. Some optical-electric composite cables are configured to prevent an increase in optical loss caused by microbending of the optical fiber (slight bending of a central axis of a core caused by pressure (lateral pressure) applied from a side surface) (See e.g. JP-A-2011-018544 and JP-A-2012-009156).
The optical-electric composite cable disclosed in JP-A-2011-018544 is constructed such that an optical fiber is arranged in the center and plural covered conductors are arranged to surround the optical fiber. In addition, high-tensile fiber such as Kevlar (trademark) is filled between the optical fiber and the plural covered conductors. In this optical-electric composite cable, an external force from outside of the sheath is absorbed by a covering of the covered conductor and is also dispersed by the high-tensile fiber, and it is thereby possible to reduce lateral pressure acting on the optical fiber.
The optical-electric composite cable disclosed in JP-A-2012-009156 is constructed such that an optical fiber is arranged so as to be in contact with an inner peripheral surface of a protective tube and plural electric wires are arranged around an outer periphery of the protective tube. In this optical-electric composite cable, since the optical fiber is protected from an external force by the protective tube, bending or twisting of the optical fiber due to the external force is suppressed and an increase in transmission loss is thus suppressed.
The related arts may be JP-A-2011-018544, JP-A-2012-009156 and Japanese patent application No. 2012-206722 (i.e., JP-B-5273284)


A method for determining a substantially optimal NMO velocity function for use in stacking a CMP gather of seismic data traces. The method begins with an initial estimate of the NMO velocity function for the CMP gather. This initial estimate is typically determined through conventional seismic velocity analysis. The method then picks a first velocity-traveltime pair falling on the initial estimate of the NMO velocity function and conducts a two-dimensional interpolative search of trial velocity-traveltime pairs in the neighborhood of the pick to find a substantially optimal velocity-traveltime pair. This substantially optimal velocity-traveltime pair is the trial velocity-traveltime pair having the highest stack response and is substituted for the pick in the NMO velocity function. The method then proceeds to find substantially optimal velocity-traveltime pairs to replace each of the other picks on the initial estimate of the NMO velocity function. Preferably, the two-dimensional interpolative search consists of a one-dimensional parabolic interpolative search to identify the optimal velocity for each computational time within a specified time window, followed by a one-dimensional search to select one of these optimal velocities which, together with its corresponding computational time, becomes the substantially optimal velocity-traveltime pair for the pick in question.

In the oil and gas industry, seismic prospecting techniques are commonly used to aid in the search for and evaluation of subterranean hydrocarbon deposits. In seismic prospecting, a seismic source is used to generate a seismic signal that propagates into the earth and is at least partially reflected by subsurface seismic reflectors (i.e., interfaces between underground formations having different elastic properties). The reflected signals (known as "seismic reflections") are detected and recorded by seismic receivers located at or near the surface of the earth, in an overlying body of water, or at known depths in boreholes, and the resulting seismic data may be processed to yield information relating to the subsurface formations.
Seismic prospecting consists of three separate stages: data acquisition, data processing, and data interpretation. The success of a seismic prospecting operation depends on satisfactory completion of all three stages.
The seismic energy recorded by each seismic receiver during the data acquisition stage is known as a "seismic data trace". Seismic data traces typically contain both the desired seismic reflections and one or more unwanted noise components which can obscure or overwhelm the seismic reflections. One of the primary objectives of the data processing stage is to remove or at least attenuate these unwanted noise components so that the desired seismic reflections can be clearly identified and interpreted.
One method for attenuating unwanted noise components in seismic data traces is through the common-midpoint (CMP) stacking process. As will be well known to persons skilled in the art, the "midpoint" for a seismic data trace is the point midway between the source location and the receiver location for that trace. According to the CMP method, the recorded seismic data traces are sorted into common-midpoint gathers each of which contains a number of different seismic data traces having the same midpoint but different source-to-receiver offset distances. The seismic data traces within each CMP gather are corrected for statics (i.e., the effects of variations in elevation, weathered layer thickness and/or velocity, or reference datum) and normal moveout (i.e., the variation of traveltime with respect to source-to-receiver offset) and are then summed or "stacked" to yield a stacked data trace which is a composite of the individual seismic data traces in the CMP gather. Typically, the stacked data trace has a significantly improved signal-to-noise ratio compared to that of the unstacked seismic data traces.
As is well known in the art, for a horizontally layered earth having a single horizontal reflector, seismic signal traveltime bears a hyperbolic relation to source-to-receiver offset distance, as follows: ##EQU1## where "t" is the seismic signal traveltime for source-to-receiver offset "x"; "t.sub.0 " is the seismic signal traveltime for zero offset; and "V.sub.NMO " is the velocity of the seismic signal (commonly referred to as the "normal-moveout velocity" or "NMO velocity").
In the CMP stacking process, seismic data traces from different source-to-receiver offsets within a CMP gather are stacked by moving them along hyperbolas defined by equation (1) to the zero-offset position and then adding them together. As is well known in the art, the NMO velocity for a CMP gather is not a constant. Typically, the NMO velocity increases sporadically as two-way, zero-offset traveltime increases. For this reason, proper stacking of the seismic data traces within a CMP gather requires knowledge of the NMO velocity as a function of two-way, zero-offset traveltime.
Typically, determination of the NMO velocity function is done manually by expert seismic analysts. One conventional method for determining the NMO velocity function is through the use of velocity spectra. According to this method, the individual seismic data traces in a CMP gather are repeatedly NMO-corrected and stacked using a range of trial velocity values. The resulting stacked traces are then displayed side-by-side on a plane of velocity versus two-way, zero-offset traveltime, known as the "velocity spectrum". The velocity which results in the highest stacked amplitude for a given reflection is selected or "picked" as the NMO velocity for that reflection. The NMO velocity function may then be expressed as a set of velocity-traveltime pairs.
Many other conventional methods for determining or "picking" the NMO velocity function are known. Typically, these methods are based on determining the velocity that corresponds to the best coherency of the signal along a hyperbolic trajectory over the entire CMP gather. Coherency may be measured in a variety of ways, such as an unnormalized crosscorrelation, a normalized crosscorrelation, and energy-normalized crosscorrelation, or semblance (i.e., stack energy normalized by the mean energy of the individual traces going into the stack).
Further information on the use of velocity spectra and other known methods of velocity analysis may be found in Yilmaz, O., Seismic Data Processing, 1987, Society of Exploration Geophysists, Tulsa, Okla., pp. 166-183.
The accuracy of the NMO velocity functions resulting from these prior art methods is limited by the discrete step size used in the set of trial velocity values. As would be well known to persons skilled in the art, manual velocity picking by even the most experienced analyst can only be accurate to within a few percent, and even a small error in the NMO velocity can result in a significant loss in signal-to-noise ratio and bandwidth in the stacked data. Furthermore, the phenomenon of "stretching" (i.e., the change in wavelet shape produced by applying a normal-moveout correction) further degrades the measurement of coherency for the coherency-based methods. Muting can be used to minimize the effects of stretching, but this reduces the fold of the stacking process (i.e., the number of individual traces that contribute to the final stacked trace for the CMP location).
In conventional seismic data processing, the NMO velocity function is determined by a seismic analyst at a plurality of laterally spaced-apart locations along the seismic line. This is a time consuming process, and, for practical reasons, the number of locations where the NMO velocity function determination is made must be limited. Stacking programs then interpolate these analyst-determined NMO velocity functions to determine the NMO velocity function for each intermediate CMP location.
Even if the analyst-determined NMO velocity functions are correct, it is not certain that the process of interpolation gives the correct NMO velocity function at intermediate CMP locations. Typically, linear interpolation is used. Lateral variations in seismic velocity need not follow a linear variation. Even small errors (e.g., one to two percent) in the NMO velocity function used for stacking can degrade the quality of the stack. This problem would be familiar to persons skilled in the art.
Obviously, it is desirable to have an accurate NMO velocity function for every CMP location along a seismic line. Moreover, given the vast amount of data resulting from a typical three-dimensional (3-D) seismic survey, a method for automatically determining accurate NMO velocity functions is highly desirable.
Prior art attempts to develop automatic methods for determining the NMO velocity function have met with only limited success. In a typical CMP gather, there may be multiple reflections and refractions in addition to the primary reflections of interest. These multiple reflections and refractions may produce spurious peaks in the coherence spectra making it difficult to determine the peak that corresponds to the correct NMO velocity. An experienced seismic analyst often can disregard these spurious peaks and correctly pick the NMO velocity function. However, a completely automatic velocity picking procedure sometimes produces an unsatisfactory solution because the multiple reflections or refractions may have greater energy than the primary reflections of interest.
Some prior art automatic velocity picking procedures attempt to emulate the main criteria followed by seismic analysts by introducing constraints on the allowable interval or stacking velocities. Starting with an initial estimate of the velocity function, a conjugate gradient scheme is used to give an improved estimate of the velocity spectra. As a starting point, this procedure requires computation of the coherency over a range of zero-offset times and velocities for a number of different CMP locations. The choice of the initial estimate can, under certain conditions, lead to different results, and the effects of stretching are present. In any case, the resolution of these automated procedures is no finer than the step size used in the coherency computation.
The prior art also teaches the addition of a penalty function to the conventional coherency measurement; this function penalizes velocity models that differ in smoothness from an initial interval-velocity model. This requires computation of the coherency over a range of zero-offset times and velocities for a number of different CMP locations. The resolution of this method is limited to the interval size used in defining the trial velocities and times, and stretching remains a problem.
Besides the limit in resolution due to the size of the velocity or time step used in the computation, the coherency-based methods are also subject to an additional loss of resolution because the coherency between the traces in a CMP gather is computed over a time window which introduces a smearing of the velocity function. This smearing can be particularly problematic when the window encompasses a strong reflection on the seismic trace. Shifting the center of the window will often produce no discernible change in the coherency value. Shortening the window might appear to be a solution to this problem, but this leads to a serious degradation of the coherency value for weak reflections where the signal-to-noise ratio is low.
If high resolution velocity estimates are desired, they may be obtained by computing the velocity spectra on a fine grid of velocities and times. This increases the computational costs greatly. It is therefore desirable to have a method for automatic velocity picking that has a higher resolution without the computational costs that would be incurred in computing the velocity spectra on a fine grid of velocities and times. One method that has been used in the prior art starts out with a computation of the velocity spectra on a coarse grid. This is followed by a search technique, using steps determined from a Fibonacci series, to compute the coherency at additional trial velocities. The Fibonacci search technique would be familiar to those skilled in the art. By successively reducing the step size, the velocity that gives a maximum of the coherency for a time window is determined. The coherency is calculated only at the velocities determined by the Fibonacci series rather than on a fine grid of velocities between the bounds specified by the analyst. This can lead to a reduction in computation time.
The Fibonacci search method still has the smearing caused by the finite time window, and the effects of stretching are present. In addition, this search technique is strictly one-dimensional, i.e., the zero-offset times are treated independently of each other and without regard to whether in fact there is a reflection within the window.
From the foregoing, it can be seen that an improved method for automatic picking of NMO velocity functions is needed. Such a method should provide for automatic picking of the NMO velocity function for traces within a CMP gather within bounds specified by the analyst. It should also provide a high resolution estimate of the NMO velocity function without an excessive computational burden, and should provide this high resolution estimate without the stretching and smearing introduced by computing the coherency function over a finite time window. The present invention satisfies these needs.

Method for determining seismic velocities