A foreign object detection sensor applied to an electric sliding door apparatus is provided. The sensor includes a contact detecting section, a change detecting section, and a determination section. The contact detection section has a pressure sensitive portion which is capable of elastically changing in form through contact with a foreign object. The contact detecting section outputs a contact detection signal. The change detecting section measures the time required for the oscillation signal for a predetermined number of cycles to be outputted within a measurement period, which is set shorter than the response time it takes from when the object makes contact with the pressure sensitive portion to when the contact detecting section outputs the contact detection signal in the case where the movable body is in the closing operation at a predetermined maximum moving speed.

The present invention relates to a foreign object detection sensor for determining whether there is a foreign object in the proximity of a sensor electrode.
Some conventional vehicles are provided with an electric sliding door apparatus for moving and sliding a door panel (movable body) provided on a side of the vehicle in the front-rear direction of the vehicle using the drive force of a motor or the like. Such sliding door apparatuses are provided with a foreign object detection sensor, such as that described in, for example, Japanese Laid-Open Patent Publication No. 2006-162374, so that foreign objects between the front end portion of the door panel and a peripheral portion of a door opening for passengers to get in and out of the body of the vehicle (opening portion) can be detected during the closing operation of the door panel.
The foreign object detection sensor described in the above described publication has a sensor electrode (antenna), an oscillator, a detection portion, and a determination section. The sensor electrode is placed along the front end portion of the door panel. This sensor electrode detects the capacitance between the sensor electrode and a foreign object in the proximity of the sensor electrode. An oscillating circuit oscillates at an oscillation frequency determined in accordance with the capacitance detected using the sensor electrode. The detection portion detects the above described oscillation frequency. The determination section determines whether there is a foreign object in the proximity of the sensor electrode, that is to say, whether there is a foreign object between the front end portion of the door panel and the peripheral portion of the door opening on the basis of the oscillation frequency detected by the detection portion. Specifically, the determination section determines that there is a foreign object in the proximity of the sensor electrode in the case where the amount of change (or inclination of change) in the oscillation frequency detected by the detection portion exceeds a preset reference value.
The foreign object detection sensor detects the amount of change in the above described oscillation frequency whenever a predetermined period of time elapses or whenever the door panel moves by a predetermined distance. In the case where an amount of change in the oscillation frequency is detected whenever a predetermined period of time elapses, the foreign object detection sensor measures values in the waveform outputted from the oscillation circuit at a first time and a second time within a predetermined period of time, and detects the amount of change in the oscillation frequency on the basis of the results of this measurement. Meanwhile, in the case where the amount of change in the oscillation frequency is detected whenever the door panel moves by a predetermined distance, the foreign object detection sensor generally measures the period in terms of the length of one wave in the waveform outputted from the oscillating circuit when the door panel moves by a predetermined distance, and detects the amount of change in the oscillation frequency on the basis of the results of this measurement.
In the case where the amount of change in the oscillation frequency is detected on the basis of the values in the waveform outputted from the oscillating circuit at the first time and the second time within the predetermined period of time, the number of cycles of the waveform outputted within the predetermined period of time changes. Therefore, there is inconsistency in the precision of the amount of change in the oscillation frequency gained for the predetermined period of time. The oscillation frequency in the oscillating circuit changes in accordance with the change in the capacitance detected using the sensor electrode, and therefore, in some cases, the number of cycles in the waveform outputted from the oscillating circuit within a predetermined period of time does not become a natural number. In such cases, the amount of change in the oscillation frequency gained for every predetermined period of time ends up having low precision.
Meanwhile, in accordance with the method for measuring the cycle in terms of the length of one wave in the waveform outputted from the oscillating circuit whenever the door panel moves by a predetermined distance, there is a risk that there may be inconsistency between the result of measurement and the actual value in the case of a measuring method with low precision.
As described above, there is a risk in the foreign object detection sensor described in Patent Document 1 that the precision in detection of the amount of change in the oscillation frequency on the basis of the waveform outputted from the oscillating circuit may be low. That is to say, there is a risk that the precision in the detection of the capacitance by the sensor electrode may be low, and the precision in the detection of foreign objects in the proximity of the sensor electrode may be low.


A piezoelectric type ink-jet printing head including a pressure chamber plate having a plurality of pressure chambers and a plurality of ink supply ports for supplying ink into the respective pressure chambers, a nozzle plate having a plurality of nozzles and a piezoelectric element having a surface, at least parts thereof defining a plurality of displacement portion. The nozzle plate is attached to one of the surfaces of the pressure chamber plate, in such a manner that the respective nozzles are connected to the respective pressure chambers. The other surface of the pressure chamber plate is attached to the piezoelectric element, in such a manner that each of the displacement portions of the piezoelectric element defines at least one of walls of each of the pressure chambers.

1. Field of the Invention
This invention relates to a piezoelectric type ink-jet printing head which can advantageously be used in an office automation machine such as a copying machine, a facsimile, a computer, a wordprocessor, a combination of these machines, or the like.
2. Description of the Related Art
An ink-jet printer is a type of printer in which liquid ink is injected through the air as small drop, a liquid column or a mist and onto a recording paper to print thereon letters, graphics, images or the like. In general, there are two types of printing heads used in such an ink-jet printer, i.e., a bubble type printing head in which bubbles are generated in the ink pressure chamber by a heater and the ink is injected by the bubble pressure, and an oscillation plate type printing head in which a pressure plate is provided at the bottom of the pressure chamber and the pressure plate is pushed by a piezoelectric actuator to inject the ink from the nozzle.
These two types of ink-jet printer heads have the following problems. In the bubble type printing head, the efficiency of the head substantially depends on the nature or the characteristics of the ink and, therefore, there are limitations in printing speed and quality. Therefore, it would be relatively difficult to satisfy the recent requirements of speed and image quality in printers using a bubble type printing head. In the oscillation plate type printing head, a pressure chamber and a nozzle are located on the upper side of a pressure plate and a piezoelectric actuator is located on the lower side of the pressure plate, so that a pressure chamber is defined between the pressure plate and the piezoelectric actuator. Therefore, the printing head is relatively complicated in construction and becomes rather expensive.
To solve the above-mentioned problems in the oscillation plate type printing head, in another type of known ink-jet printing head a part of the pressure chamber is constituted by an electrode of the piezoelectric element by itself, so that the pressure chamber is compressed by the displacement of the piezoelectric element to inject the ink in the pressure chamber through the nozzles. In this respect, the following types of ink-jet printers have been proposed in the prior art.
Japanese Unexamined Patent Publication (Kokai) No. 4-64448 discloses an ink-jet recording apparatus in which a piezoelectric element is provided with several slits to make respective actuators in the projected portions divided by these slits and parallel passages are formed in conformity with the respective projected portions, so that a displacement of the actuator in a direction perpendicular to the parallel passages can be obtained. Thus, ink in a common chamber connected to one end of each parallel passage can be injected from nozzles provided at the other end of each end parallel passage. The piezoelectric element comprises non-active areas where there are no electrodes and the thickness thereof is not changed and active areas where there are electrodes and the thickness thereof is changed. These active areas are located so as to define at least one wall of the parallel passages. The slits are filled with any filler.
However, in this ink-jet recording apparatus, since the individual actuators are divided by means of a plurality of slits in the piezoelectric element, the construction thereof is rather complicated and therefore expensive.
Japanese Unexamined Patent Publication (Kokai) No. 3-272855 discloses an ink-jet printing head comprising a base substrate, a common electrode formed thereon a piezoelectric material formed on the substrate, and a local electrodes formed on the piezoelectric material. A voltage is applied across these electrodes at the resonant frequency, in the thickness direction, of the piezoelectric material to effectively compress the ink. The pressure chamber is not divided but is common to all of the nozzles.
In this ink-jet printing head, since the pressure chamber is not divided but is commonly used for the plurality of nozzles, the structure of the pressure chamber can be simplified. On the other hand, it is difficult to keep constant the amount of ink injected from the individual nozzles and, therefore, the printing quality is reduced. Also, the direction of the ink-jet is restricted to the direction of displacement of the piezoelectric material and, therefore, it is difficult to constitute an "edge shoot" type printing head in which ink is injected in a direction perpendicular to the displacement of the piezoelectric material.
Japanese Unexamined Patent Publication (Kokai) No. 6-188475 discloses a laminated piezoelectric element in which piezoelectric material and electrodes (common and local electrodes) are alternately laminated, so that an electric field can be selectively generated in the laminated direction. A voltage is applied to the laminated piezoelectric element to exert a pressure in the pressure chamber to inject the ink from the nozzle.
However, when a pressure is exerted in the pressure chamber by the laminated piezoelectric element, since the piezoelectric element is buried in the recess of the base substrate and the walls of the pressure chamber (at least a part thereof) are not defined by the piezoelectric element, pressure is indirectly exerted to the ink in the pressure chamber by means of a membrane. Therefore, a large pressure cannot be obtained.
Japanese Unexamined Patent Publication (Kokai) No. 4-341853 discloses a piezoelectric-type ink-jet printer head comprising a laminated piezoelectric element having a plurality of divided inner electrodes and local displacement portions which are locally displaced when a voltage is applied to the electrodes. The thickness of one layer of piezoelectric material of the laminated piezoelectric element is 40 to 150 .mu.m.

Piezoelectric type ink-jet printing head having a pressure chamber plate which is less flexible than piezoelectric elements


A camera system is disclosed, which can obtain an accurate target driving amount when the target driving amount of a focusing lens is calculated while the focusing lens is driven. The camera system has a camera and a lens apparatus which has an image taking optical system including a focusing lens and is mounted on the camera. The camera has a photoelectric conversion element which photoelectrically converts an optical image, a focus information producing section which produces focus information based on the output of the photoelectric conversion element, and a communication unit which transmits timing information of the photoelectric conversion and the focus information to the lens apparatus. The lens apparatus has a memory which stores an optical information changing according to the position of the focusing lens, and a controller which controls the driving of the focusing lens.

1. Field of the Invention
The present invention relates to a camera system for calculating a target driving amount by using the focus information of an image-taking optical system while a focusing lens is driven.
2. Description of Related Art
A TTL (through the lens) type camera for performing focusing of the image-taking optical method by using a phase difference detection system is conventionally known, wherein the focus detection operation is repeatedly performed while the focusing lens is driven so as to shorten the time to be required for focusing (re-focus detection operation during driving, hereinafter, referred to as "overlap operation").
An automatic focus controller is disclosed in Japanese Patent Publication No. H04 (1992)-10051, which performs the focus detection repeatedly while stopping and moving an image taking lens, and moves the image taking lens to an in-focus position while correcting the driving amount of the image taking lens.
Herein, it will be considered that the overlap operation described above is applied to the following camera system. This camera system captures an optical image formed by the image-taking optical system by using an image sensor provided in a camera body. In addition, the camera system obtains a defocus amount based on the signal showing the amount of detected light from the image sensor, and transmits the defocus amount to the side of an interchangeable lens. The interchangeable lens calculates the driving amount of the focusing lens based on the received defocus amount, and moves the focusing lens to a target position (in-focus position).
For example, Japanese Patent Laid-Open No. H05(1993)-196863 discloses a technique wherein the driving of the focusing lens is controlled by transmitting the defocus amount from the side of the camera body to the side of the interchangeable lens, and converting the defocus amount into the lens driving amount on the side of the interchangeable lens.
Herein, the calculated defocus amount can be converted into the driving amount of the focusing lens at the side of the camera body, and the driving amount can be transmitted to the side of the interchangeable lens. The focusing lens can be driven based on the lens driving amount received at the side of the interchangeable lens. However, in this case, it is necessary to acquire various kinds of optical data (sensitivity coefficient or the like corresponding to a focal length and lens position) of the interchangeable lens by communications, which is required when the camera body converts the defocus amount into the lens driving amount. Therefore, the camera system for transmitting the defocus amount to the side of the interchangeable lens has the advantages for which the number of communications (transmitting and receiving data) can be remarkably reduced compared with the case that the lens driving amount is transmitted to the side of the interchangeable lens, and the communications load can be reduced.
Herein, in the camera system for transmitting the defocus amount to the interchangeable lens, the focusing lens is moved from the time when detecting the amount of light necessary to calculate the defocus amount to the time when calculating the defocus amount and transmitting the defocus amount to the interchangeable lens while the overlap operation is performed, that is, in the time obtained by adding the charge storage time with respect to the object light, the calculation time and the communications time, and even during the time before converting the defocus amount received at the side of the interchangeable lens into the lens driving amount.
The relationship thereof will be described with reference to FIG. 11. FIG. 11 shows one example of the relationship between the lens driving speed and the lens position (pulse count value) from the start of the driving of the focusing lens until the attainment of the target position. Though timings shown by A to E in FIG. 11 show the timings of the operations to be described below schematically, these timings do not necessarily coincide with those in FIG. 11.
In the driving of the focusing lens, the focusing lens is firstly accelerated immediately after the start of the driving, and the lens driving speed is increased up to a constant speed. The deceleration is started when the lens position is set in a predetermined position after the lens driving speed is set to a constant speed, and the focusing lens is stopped at a target position. Herein, the overlap operation is performed only at the time at which the lens driving speed is set to a constant speed. The reason is that the overlap operation causes errors in the focus detection while the focusing lens is accelerated or is decelerated.
The charge storage operation is started in the image sensor of the side of the camera body for calculating the defocus amount when the overlap operation is performed (timing A in FIG. 11), and the charge storage operation is ended after passage of a predetermined time (timing B in FIG. 11). Herein, a storage center timing means the intermediate between the timing at which the charge storage is started and the timing at which the charge storage is ended.
The defocus amount is then calculated based on the light amount signal (accumulated charge) readout from the image sensor (timing C in FIG. 11), and data concerning the defocus amount is transmitted to the side of the interchangeable lens. The interchangeable lens receives the data concerning the defocus amount transmitted from the camera body (timing D in FIG. 11), converts the defocus amount into the lens driving amount, and starts the driving of the focusing lens (timing E in FIG. 11).
As shown in FIG. 11, the focusing lens is moved between the storage center timing and the timing E at which the lens drive is started. Therefore, various kinds of optical data (sensitivity coefficient or the like corresponding to the focal length and lens position) of the lens used for converting the defocus amount into the lens driving amount may be changed between the storage center timing and the timing E. The lens driving amount may not be accurately calculated when various kinds of optical data are acquired after the defocus amount is received.
When the focusing lens is driven by the lens driving amount calculated based on the optical data which does not correspond to the present position of the focusing lens, the focusing lens exceeds the in-focus position by only the extent that the focusing lens is moved. In this case, it is necessary to correct the lens driving amount appropriately for stopping the focusing lens at the in-focus position.

Camera system, lens apparatus and camera


A intelligent network interface network port (INIP) is provided that enables a visiting computer to be connected to a local area network (LAN), even though the LAN is not configured to support the visiting computer. Upon detecting one of several specific types of messages, the INIP modifies the message, retransmits the modified message and notifies the visiting computer that the INIP is the appropriate target for the message, thus acting as a relay point between the visiting computer and other devices both on the LAN and accessible through it. This enables the visiting computer to transparently connect to a LAN that is not configured to support it.

1. Technical Field
The invention relates generally to an apparatus for and a method of connecting a computer to a network and, more specifically, to a network connection adapter that enables a local area network (LAN) to provide Internet access to a computer that is not a configured member of the LAN.
2. Description of the Related Art
Since computers were invented, people have been connecting them together. Computers were originally connected in resource-sharing schemes to provide multiple access to expensive resources such as printers and disk memory. Next, local area networks (LANs) were developed using a variety of protocols such as Ethernet and, then metropolitan area networks (MANs) and wide area networks (WANs) were created. Today, millions of computers are connected in the large, WAN-like architecture of the Internet, which provides users with access to an enormous amount of resources spanning the planet. The Internet is rapidly changing the way that people work, communicate and share information.
During the period when networks were developed, computers themselves were also changing. The original computers had little processing power and memory by today's standards and often filled a room the size of a warehouse. Today, computers, or workstations, have orders of magnitude more processing power and memory and can weigh only a few pounds. The combination of small, portable workstations and the networking of multiple workstations has created a number of issues. For example, when a user travels with a computer, it is often desirable to connect the computer to a network that is different than the user's typical network. This may present a problem because most networks are configured to respond to specific computers, and it is impractical to reconfigure a network each time a user is visiting with a non-local computer.
There are techniques that partially address this issue. First, developers created a bootstrap protocol ("BOOTP"). The BOOTP which enables a diskless workstation to discover an assigned internet protocol (IP) address, an IP address of a BOOTP server and the location of a boot file to be copied, or "downloaded." In this manner, the workstation can load the information it needs to operate on a host network when the workstation is powered up. However, the host network typically must maintain an assigned IP address that corresponds to a unique hardware address associated with the workstation's network interface card (NIC). In the case of a visiting computer, this is probably not the case.
Two other systems that assign IP numbers to computers on a network are the Point-to-point protocol (PPP) and the dynamic host configuration protocol (DHCP). Both PPP and DHCP are protocols in which a network server assigns an IP address upon request. The network server may assign a domain name system (DNS) server as well. These features can simplify network administration because software on the network server rather than a system administrator keeps track of IP addresses. PPP and DHCP are commonly used for dial-up computer users. However, a visiting computer may not be configured for either PPP or DHCP; and neither PPP nor DHCP address the issues faced by a computer that does not support either protocol. In addition, some computers may be configured to accept only partial; information about a DNS server from DHCP. When such a computer attempts to connect to a network that is not configured to recognize it, the computer cannot communicate with other computers on the network and cannot locate a DNS server for communication to computers outside the network.

Intelligent network interface port for visiting computers


An audio/visual display system incorporated into a beverage dispenser assembly, the dispenser assembly including a spigot, a flow/non-flow dispensing handle operatively engaging the spigot and a selected beverage for dispensing through the spigot. A structure is arrayed atop the dispenser assembly and includes an advertising display for presenting visual advertising including both textual and graphical components. A central processor unit is either incorporated into the structure in communication with the advertising display or provided in a stand alone computerized hard drive which is connected to the structure. The processor unit is capable of storing audio/visual messages, being inputted with custom created messages and presenting menu displays corresponding to stored messages. An accompanying audio playback component is arranged in operative communication with an output of the processor unit and is either provided with an audio playback transducer incorporated within the display system structure or as a stand alone speaker arranged in proximity to the display system.

1. Field of the Invention
The present invention relates generally to information display devices and, more particularly, to a beer tap or beer tower arrangement which incorporates a customizable display system with multi-media output means into a display portion incorporating an information display carrier and a visual display means.
2. Description of the Related Art
Visual display means are fairly well know in the art, the most typical of which is the electronic display board which is supplied by an external processor with data and which displays the data in a scrolling manner across the display face of the board. Such display boards are typically found in bars and other type establishments and are useful in relating such information as sporting event scores and other news.
The primary disadvantage of such display means involves their relatively large size which makes difficult optimal location of the display board for viewing by the patrons of the establishment. An additional disadvantage of these display means is that they are usually hooked into an external processor control and supply means such that the information they display is not controlled by the establishment and, consequently, food and beverage specials of the establishment cannot be displayed.
An example of a computerized beer dispensing system which includes a tap display is described in U.S. Pat. No. 4,979,641, issued to Turner. The primary objective of Turner is to disclose a dispensing system which tracks variables of draft beer dispensings, such as accounting, inventory control, price variations and time periods associated with price variations. An additional feature taught by Turner is the annunciating of public relation type messages and this is provided in part by front and rear displays located on associated front and rear faces of a dispenser housing, from which also extends a dispensing tap. The displays are identified as being of vacuum fluorescent construction and are capable of displaying all the programmed functions relating to the variables of the beer dispensing system. Turner also teaches that the displays present additional programmed messages including beer advertisements and other location operator programmed announcements during default of the primary programming functions. According to this feature, an operator can select the content and time duration of standard or customized computer generated messages which are displayed at desired intervals and are stored in a message queue.
While teaching an interesting secondary display feature of a beer dispensing tap which is otherwise primarily directed to dispensing and accounting functions, the advertising display aspect of Turner suffers from the shortcoming that the output is limited to a flashing or scrolling written message presented across the display faces. Turner does not appear to be either intended or suited for providing advertising and entertainment display, particularly of a multi-media nature, in which both audio and visual design aspects are used selectively in combination with printed messages. The advantage of such multi-media outputs is to provide a more discernable and sophisticated audio/visual presentation for a beer tap dispensing assembly than that which is currently afforded by the prior art.

Beer tap display system with customizable programming and multi-media output means


A magnetic recording/reproducing device comprises a recording head for magnetically recording a signal on a magnetic recording medium along a predetermined track, and a reproducing head member including a spin valve typed magnetoresistive element and bias magnetic applying means, associated with the spin valve typed magnetoresistive element, for applying a bias magnetic field to the spin valve typed magnetoresistive element, the reproducing head member for changing a sensitivity distribution in a track width direction based on a distance between the reproducing head and the recording head, and an angle difference between the direction of the reproducing head and the extending direction of the track.

The present invention relates to a magnetic recording/reproducing device such as a hard disk device and particularly to a magnetic recording/reproducing device using a composite head.
A magnetic recording/reproducing device such as a hard disk device is frequently used as an outer storage device having a large, which is capable of accessing at random. In recent years, high recording density for enlarging storage capacity has been greatly demanded, and the study and development have been made in various angles to meet the demand.
Generally, in the hard disk device, a plurality of magnetic disks, each which is formed on a non-magnetic substrate to have a magnetic layer, are stacked on one rotation spindle. A head for recording/reproducing is attached to an arm to be opposite to each disk surface. The arm is moved to a radial direction of the disk so that the head is positioned. In other words, a seek operation is executed. At a signal recording/reproducing time, the head slightly floats, and is placed to access to a predetermined position of the disk surface in such a state without directly contacting the disk surface rotating at high speed. Then, a signal is recorded onto a concentric track on the disk surface by the head, or the recorded signal is reproduced.
In order to meet the demand of high recording density for enlarging storage capacity, various trials have been made so far. For example, a linear recording density of the disk, that is, recording density in the length direction of the track is increased. Or, a track width is narrowed to increase the track density, thereby improving recording density. In recent years, for further improving the recording density, there has been enthusiastically made the study and development of a contact recording in which the head is floated extremely lower or the head is brought in substantially contact with a recording medium.
On the other hand, to improve sensitivity of a signal reproduction, an active typed head, e.g., an MR head using magnetoresistive effect, has been developed. The MR head is a head, which converts a magnetic flux sent from the recording medium to an electrical signal by use of a property in which an electrical resistance of a soft magnetic member such as permalloy is changed by an outer magnetic field. The MR head converts the change of the electrical resistance of an MR element formed of the soft magnetic member to a voltage change. Due to this, the sensitivity of the signal reproduction of the head is proportional to an amount of sense currents flowing to the MR element. As a result, even if a relative speed between the head and the medium is small, a large reproducing output can be obtained. Also, by use of the feature in which the reproducing output of the MR head is large, the track width can be narrowed to improve the track density.
The reproducing head, which is formed of the MR head, is frequently used to be combined with a recording head, which is formed of an inductive head, thereby forming a composite head. In this case, the reproducing head is combined with the recording head to be spaced from each other with a predetermined distance in the track direction. The composite head is mounted on a head slider. The composite head is moved in a radial direction of the disk by a rotary actuator through the head slider. Then, the positioning to a target track, that is, the seek operation is performed. At the seek operation time, a track shift occurs between the recording head and the reproducing head due to the space existing between the recording head and the reproducing head in the direction of the track. In this case, the track shift means that the relative position between the head and the track differs by depending on the recording head and the reproducing head.
The mechanism of the track shift will be explained with reference to FIGS. 1A and 1B. FIGS. 1A and 1B are views each schematically showing a state that the composite head moved by the rotary actuator is positioned at an inner peripheral track on the magnetic disk and an outer peripheral track. As shown in the figures, for moving the composite head by the rotary actuator, an angle difference between the direction of the head (azimuth direction) and the direction of the track, that is, skew angle, is changed by depending on the track radial direction where the head is positioned. In FIGS. 1A and 1B, a skew angle xcex8 is negative at the inner side (small diameter), and positive at the outer side (large diameter). The change of the skew angle appears as the track shift between the recording track and the reproducing track at it is. The track shift is increased as the track pitch is narrowed, and this brings about an obstacle to a correct reproduction.
Moreover, if the track width is narrowed to obtain high track density, it is necessary to increase the accuracy of positioning of the recording head and the reproducing head in the track width direction. However, if the track is narrowed, the tolerance between the recording head and the reproducing head in the positioning is relatively increased in view of the accuracy of the manufacturing process. This brings about an obstacle to obtain high track density.
Moreover, there is proposed a two-stage (two-dimensional) control typed head driving mechanism in which the rotary actuator is used as a coarse actuator and a mechanical fine actuator is used as a minor actuator. By use of this head driving mechanism, the composite head is controlled such that the recording head is mounted on the track at the recording time and the reproducing head is mounted on the track at the reproducing time. Due to this, for frequently repeating the recording and reproducing operations, the whole composite head must be frequently driven. As a result, it takes time to center a predetermined recording head or a reproducing head on a target track correctly.
In a case where the space between the head and the medium is extremely small and both contact with each other, its contacting force is added to the micro-actuator as disturbance. As a result, the head driving mechanism cannot be sufficiently functioned, and the tracking cannot be controlled with high accuracy.
Thus, in the magnetic recording/reproducing device using the composite head, there is the problem of the track shift. Then, the track shift causes the reduction of the reproducing output. Moreover, the track shift hinders the track pitch from being narrowed. Also, the track shift hinders the track density from being highly increased.
An object of the present invention is to provide a magnetic recording/reproducing device in which a track pitch can be narrowed, the high density of the track can be obtained, and a large reproducing output can be obtained.
The above object can be attained by the following magnetic recording/reproducing device:
Specifically, there is provided a magnetic recording/reproducing device comprising:
a recording head for magnetically recording a signal on a magnetic recording medium along a predetermined track;
a reproducing head, having a spin valve typed magnetoresistive element, for reproducing the signal recorded on the magnetic recording medium in which a sensitivity distribution in a track width direction is changed in accordance with an external control signal; and
controlling means for supplying the external control signal to the reproducing head.
The above-mentioned object can be also attained by the following magnetic recording/reproducing device:
Specifically, there is provided a magnetic recording/reproducing device comprising:
a recording head for magnetically recording a signal on a magnetic recording medium along a predetermined track;
a reproducing head, having a spin valve typed magnetoresistive element, for reproducing the signal recorded on the magnetic recording medium; and
a conductive member, magnetically associated with the magnetoresistive element, to which a current is supplied in accordance with time and positional behavior among the track, recording head, and reproducing head.
Moreover, the above-mentioned object can be attained by the following magnetic recording/reproducing device:
Specifically, there is provided a magnetic recording/reproducing device comprising:
a recording head for magnetically recording a signal on a magnetic recording medium along a predetermined track; and
a reproducing head member including a spin valve typed magnetoresistive element and bias magnetic applying means, associated with the spin valve typed magnetoresistive element, for applying a bias magnetic field to the spin valve typed magnetoresistive element, the reproducing head member for changing a sensitivity distribution in a track width direction based on a distance between the reproducing head and the recording head, and an angle difference between the direction of the reproducing head and the extending direction of the track.
Furthermore, the above-mentioned object can be attained by the following magnetic recording/reproducing device:
Specifically, there is provided a magnetic recording/reproducing device comprising:
a recording head for magnetically recording a signal on a magnetic recording medium along a predetermined track; and
a reproducing head including a spin valve typed magnetoresistive element and means for sending a current, for applying the bias magnetic field to the spin valve typed magnetoresistive element by a shunt bias effect, to the spin valve typed magnetoresistive element itself in which the current to be sent to the spin valve typed magnetoresistive element itself by the means is defined based on a distance between the reproducing head and the recording head, and an angle difference between the direction of the reproducing head and the extending direction of the track.
Thus, according to the present invention, a GMR head using the spin valve typed magnetoresistive element (GMR element) (to be specifically described later) is used as the reproducing head of the composite head. Then, the center of the sensitivity distribution of the GMR head is moved, so that a large reproducing; output can be obtained by use of the GMR head. Also, Moreover, even if the center of the sensitivity distribution is moved, the track pitch can be narrowed and the high density of the track can be obtained without largely generating the crosstalk between the tracks. The main feature of the present invention lies in the following point:
Specifically, the characteristic of the sensitivity of the GMR head is symmetrically shown. Then, even if the center of the sensitivity distribution is moved, the entire characteristic curve is moved without spreading the lower edge portion of the characteristic curve.
On the other hand, the sensitivity distribution of the reproducing head is controlled by the magnetic field applied to the spin valve typed magnetoresistive element. Thereby, as compared with the mechanical head drive mechanism, a servo zone, that is, a drive frequency band of the head can be greatly highly set. In other words, in the case of the conventional mechanical actuators such as the rotary actuator, the micro actuator, etc., the servo driving cannot be performed with a frequency exceeding 10 kHz. In contrast, in the system for magnetically moving the sensitivity distribution of the reproducing head according to the present invention, a driving object of the fine actuator function is the sensitivity distribution, which is a magnetic characteristic of the reproducing head itself. Therefore, unlike the mechanical actuator for driving the reproducing head itself, according to the present invention, since the driving object has no mass, the servo driving can be performed with a frequency higher by an order of magnitude than the case of using the mechanical actuator. As a result, the positioning control having extremely high response can be performed. Even in a case where the recording and reproducing are frequently repeated, it is possible to reduce a period of time, which is needed to center a predetermined recording head or reproducing head on a target track.
Moreover, if the sensitivity distribution of the reproducing head is magnetically moved, no unfavorable influence is exerted on the head driving even if disturbance caused by the mechanical contact between the head and the medium is added to the head. As a result, the head positioning control can be stably performed.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

Magnetic recording/reproducing device using composite head


There is provided a module management apparatus, that coordinates, in a time of start of a module management infrastructure carrying out integrated management of: a bundle having a module formed by a program described by an object oriented language and definition information including an attribute of the module; and a module group including a plurality of pieces of the bundle, when the bundle is loaded from a folder, and, if the definition information collides between different bundles, a reference relationship of the bundle by changing the definition information dynamically.

In an object oriented language having a class loading mechanism of a delegation model represented by Java (a registered trademark), a module is classified by a fully-qualified class name made by combining a class with a package name. As a result, even for classes having a same name, they can be classified as different class definitions by seeing a package name. In such language, it is possible to make packages and classes be integrated into a file as a module bundled for each provided function and distribute it.
Also, as a result of improvement of the performance of a computer and improvement of development efficiency, large-scale systems using a huge number of modules are increasing. In such a system, a dependence relationship exists between modules constituting the system, and the system is founded on a module of a specific version referring to another specific module to provide a specific function.
However, along with an enlarging scale of a system due to system updates and addition of functions, management of names, providing functions, versions, allocated places and the like of modules become complex. Therefore, problems such as collision of module names and packages, unexpected version dependence and an overlap of modules have been caused.
Accordingly, in recent years, a module management infrastructure which manages modules in units of bundles has been developed. A bundle includes definition information on the bundle in addition to a module. Definition information is a name that is called a symbolic name, a version number, a bundle to be referred to and the like. In a module management infrastructure, a module is classified by a pair of a symbolic name and a version number.
A module management infrastructure can verify versions and dependency relationships of bundles that are under control at the time of its activation, and detect collision of definition information of bundles and a mismatch of dependency relationships beforehand. Also, a module management infrastructure can update a bundle dynamically by managing a life cycle of the bundle. Therefore, according to a module management infrastructure, even in an environment where a system cannot be stopped, update as a bundle is possible. Recently, a module management infrastructure has been adopted in an application server and an integrated development environment, and the features such as a dynamic addition/deletion of a module and a non-stop module update are being utilized effectively.
For example, in patent document 1 (Japanese Patent Application Laid-Open No. 2012-93979), a technology which reduces a management load for modules by automatically generating a manifest file including definition information such as a symbolic name, a version number and a dependency relationship of a module in a module management infrastructure is disclosed.
Thus, in a module management infrastructure, a module which is made by dividing a program for each function is managed using a bundle including definitions such as a name and a version. Then, the module management infrastructure can perform state control of start and stop, confirm a dependency relationship with other bundles, and provide those functions to applications as a service.
However, although applications enjoy convenience thanks to these functions of a module management infrastructure, on the other side of a coin, the stringency of management of modules is increased, and thus more careful attention is needed for setting and updating definition information on a module than ever.
In a module management infrastructure like the one described in patent document 1, a pair of a version number and a symbolic name needs to be unique over the whole infrastructure. Therefore, there is a problem that, when a bundle having a same version number and a symbolic name has already exist on the module management infrastructure, a bundle added later is not loaded due to an error by collision of definition information on the bundles.
In a general module management infrastructure, it is possible to load bundles between which collision can happen, and give them bundle IDs in order of loading. However, there is a problem that another bundle having been added assuming use of a bundle of not being a management object refers to a wrong bundle, and, as a result, there is a possibility that an unexpected execution result will be caused.
An object of the present invention is to provide a module management apparatus, a module management system and a module management method which settle collision of definition information on bundles to enable coexistence of the bundles without correcting a bundle body, and compose a dependency relationship between the bundles correctly.

Module management apparatus, module management system and module management method


A computing device may be configured to provide a shared N4 termination function for a plurality of Session Management Function (SMF) instances of an SMF Set and interface with one or more User Plane Function (UPF) instances. To achieve this, the computing device may operate a server configured with a Remote Procedure Call (RPC)-based protocol (e.g. gRPC Remote Procedure Call or “gRPC”) for a Packet Forwarding Control Protocol (PFCP) message service for serving a plurality of client stubs respectively situated at the plurality of SMF instances. The server may perform processing associated with each client stub by receiving an RPC-based protocol message which indicates a request, unpacking the RPC-based protocol message for obtaining PFCP message request data, and operating or interfacing with a PFCP message handling client for sending a PFCP message having the PFCP message request data to an indicated one of the UPF instances.

The Fifth Generation (5G) Core (5GC) architecture for a 5G network is based on the Third Generation Partnership Project (3GPP) Technical Specification (TS) 23.501. According to the 5GC architecture, a Session Management Function (SMF) may maintain a Packet Forward Control Protocol (PFCP) session with a User Plane Function (UPF) over an N4 interface. This N4 connection may be established for every Protocol Data Unit (PDU) session created by a user equipment (UE) so that the SMF may control the session.
Recently, 3GPP Release 16 (e.g. 3GPP TS 23.501, 29.244) introduced the concept of a Network Function (NF) Set, where all NF instances within the NF Set are able to share the same user context data of a UE. For example, an SMF instance may be part of an SMF Set of multiple SMF instances that share the same user context data of a UE. Given multiple SMF instances within an SMF Set, and the potential use of multiple UPF instances in actual deployment, the number of N4 connections between SMFs and UPFs multiply such that connection management at the SMF becomes overcomplicated.

Packet forwarding control protocol (PFCP) message service using a remote procedure call (RPC) based protocol suitable for PFCP connection sharing


An end effector (10) for an industrial robot has the ability to pick up plural objects, selectively rotate same and adjusts the spacing between the plural objects as the products are being carried by the robot to a desired deposit location. This functionality is achieved by locating a rotary actuator (16) at the end (8) of a robot arm and providing a lazy tong linkage assembly (60) to which plural product graspers (62) are affixed where the lazy tong assembly is carried by a rotatable platform (18) of the rotary actuator. The rotary actuator, the lazy tong assembly and the product graspers are preferably pneumatically actuated.

I. Field of the Invention
This invention relates generally to pick-&-place robotics, and more particularly to end effectors used on such equipment.
II. Discussion of the Prior Art
In the packaging industry, many of the tasks that had been carried out manually are now performed by industrial robots. As an example, such robots have been designed to pick up individual products from a first conveyor exiting a high-speed wrapping machine and transporting the wrapped products to a box or carton traveling along a second conveyor. A problem results, however, if the product size and/or shape are such that it can fit into a carton only if oriented precisely in a certain disposition. Then, too, if the robot is to simultaneously pick up a plurality of products from a conveyor, rather than one at a time, and the products are traveling down a flighted conveyor, it presents a problem of how to deposit the products as a group into a carton in a contiguous relationship.
For purposes of example only, assume for the moment that the products leaving the wrapping machine are candy bars of a defined length, width and thickness dimension and that they are traveling between lugs or fins of a flighted conveyor that maintains a predetermined gap between products. Assume further that it is desired to deposit a predetermined count of the candy bars, say, one dozen, in an open top rectangular carton as the carton moves down a second conveyor running parallel to the first. The robot employed must be able to simultaneously pick up plural bars from the flighted conveyor, squeeze the several bars together to eliminate the spacing therebetween and then deposit the plural bars as a group in the carton and then repeat the process until the desired count has been boxed. Depending on the dimensions of the candy bars and the dimension of the carton, it may also be necessary to rotate the group of bars while in transit, via the robot, so that they will be properly aligned for deposit into the box.
It is the principal object of the present invention to provide an improved end effector for an industrial robot for use in pick & place applications.
Another object of the invention is to provide an end effector capable of compressing and expanding the spacing between plural product grasping devices comprising the end effector.
Still another object of the invention is to provide an end effector for a robot having a rotatable head capable of both rotating plural products and expanding and contracting the spacing between the plural products picked up by the end effector as the products are being carried by a robot.

Rotatable, squeeze-spread end effector for industrial robot


A system and method for uplink multi-antenna power control in a communications system are provided. A method for user equipment operations includes determining a transmit power level for transmit antennas of the user equipment having at least two transmit antennas, and setting a power amplifier output level for each of the at least two transmit antennas in accordance with a respective transmit power level.

Generally, a transmit power level of an uplink channel from a User Equipment (UE, also commonly referred to as a Mobile Station, Terminal, User, Subscriber, and so forth) to an enhanced NodeB (eNB, also commonly referred to as a Base Station, NodeB, Controller, and so on) may be set at a determined level to achieve a desired level of uplink performance, help maximize battery life of the UE as well as mitigate interference to other UEs and eNBs, as well as other electronic devices, operating in the general vicinity of the UE. Furthermore, the proper setting of the transmit power level may also help improve multiple input, multiple output (MIMO) antenna performance. Setting the transmit power level may often be referred to as power control.
In The Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) Release Eight (Rel-8) technical standards, uplink power control is specified only for single transmit antenna situations. However, in subsequent releases of the 3GPP LTE technical standards, such as Rel-10 and beyond (also known as LTE-Advanced), uplink Single User MIMO (SU-MIMO) also known as spatial multiplexing is introduced and uplink power control needs to be extended to handle situations with UEs having multiple transmit antennas. Uplink power control over multiple transmit antennas is especially important in the case of multiple layer/multiple codeword transmissions.
Currently used techniques for multiple transmit antenna power control involve the use of extensions of existing single transmit antenna power control schemes, which may not provide optimal results in multiple transmit antenna situations.

System and method for uplink multi-antenna power control in a communications system


Systems and methods for call forwarding in a telecommunications network are described herein. A request to update a call forwarding number associated with a subscriber in the telecommunications network is provided. The request includes a phone number of an active mobile device, which is located within geographic proximity to a subscriber mobile device. The active mobile device is associated with a priority level.

Service providers offer services to their customers in response to customer orders, change requests and other processes. One particular class of service providers is telecommunications service providers, which provide telecommunication services to their customers, referred to as subscribers. Telecommunications services currently include both wire line and wireless technologies. Examples of wire line telecommunication services include telephone service and related services such as voice mail, call forwarding, three way calling and caller identification, or cable television service and associated cable-provided services, such as Internet access. Examples of wireless telecommunication services include cellular telephone service and associated services such as call forwarding, voice mail and three way calling, wireless electronic mail and paging.
More and more types of services are emerging on various networks. Telecommunication networks in particular are expanding offerings of new services to retain current customers and add new service accounts.

Systems and methods for call forwarding to a device based on a priority level and geographic proximity

Hewlett-Packard Development Company, L.P.


A method is disclosed for the conditional deletion of selected data objects within a data processing system. In a data processing system having a plurality of data objects stored within a library service, it is common for a selected data object to be utilized or temporarily removed by a system user. In response to a request to delete a selected data object, a determination is first made whether the data object in question is in use or temporarily removed from the library service. If the data object to be deleted is in use or temporarily removed, the deletion of that data object is automatically halted in accordance with the method of the present invention. In one embodiment of the present invention, the deletion of a selected data object may be temporarily deferred in response to a determination that the data object is in use or temporarily removed, until such time as the data object is returned to the library service or no longer in use. In each disclosed embodiment of the present invention, the authority to delete a particular data object is determined prior to permitting such deletion.

1. Technical Field
The present invention relates in general to methods for improving data processing systems, and in particular to methods for maintaining data integrity within data processing systems. Still more particularly, the present invention relates to methods and systems for conditionally deleting data objects within a data processing system.
2. Description of the Related Art
It is common within known data processing systems to group a plurality of data objects or documents within a library service so that these data objects may be utilized and/or temporarily removed by users within the system. As is typical in these known systems, the ability of a particular user to utilize or temporarily remove a particular data object is selectively defined by setting forth a level of authority which that user may enjoy with regard to a particular data object.
For example, a particular user may be authorized to read a particular document but not to copy or delete that document. However, in the case of each document within a data processing service, a particular user designated as the owner of that document, or a user given the highest level of authority with regard to that document, may specify that a particular document be deleted from the library service wherein that document is maintained.
This particular activity can create a problem in known data processing system environments in that a document owner or a user with sufficient authority may request that a document be deleted and have the library service responsible for that document delete the document, regardless of whether the document is in use or temporarily removed from the library service by a second user. In the case of a document which has been temporarily removed, known library services will delete all references to that document and an error message will be generated upon an attempt by a second user to check the document back into the library service. Of course, those skilled in the art will appreciate that the deletion of a document by the document owner while the document is in use by a second user will clearly have a negative impact on data integrity and perceived user-friendliness within the data processing system.
Therefore, it should be obvious that a need exists for a method and system whereby the deletion of a document from a library service within a data processing system may be conditioned upon the document being resident within the library service and not being currently in use by a second user.

System for authorized conditional deletion of data objects within a library service

International Business Machines Corporation


The preparation of azitromycin dihydrate from 9-deoxo-9a-aza-11,12-deoxy-9a-methyl-9a-homoerythromycin A 11,12-hydrogenorthoborate, obtained by a step by step process starting from 9-deoxo-6-deoxy-6,9-epoxy-9,9a-dihydro-9a-azahomoerythromycin A is a process which takes place under mild conditions and with good yields.

1. Field of the Invention
Azitromycin is the USAN generic name of the product 9-deoxo-9a-aza-9a-methyl-9a-homoerythromycin A, which constitutes the first example of a new class of antibiotics (azalides) and is an effective therapeutic agent in the treatment of sexually transmitted diseases, infections of the respiratory apparatus and infections of the skin (H. A. Kirst, G. D. Sides, Antimicrob. Agents Chemother, 1989, 33, 1419-1422).
2. Description of the Prior Art
FIG. 1 shows the bibliographical background in relation to the synthesis of this macrolide. Azitromycin was first described by S. Djokic and G. Kobrehel in the Belgian Pat. No. 892,357 and in its related U.S. Pat. No. 4,517,359, obtained by means of the reductive alkylation of 9-deoxo-9a-aza-9a-homoerythromycin A (3), by treatment of said amine with a mixture of formic acid and aqueous formaldehyde under chloroform reflux, following the classical experimental conditions of the Eschweller-Clarke reaction.
The synthesis of 9-deoxo-9a-aza-9a-homoerythromycin A (3), is described by S. Djokic and G. Kobrehel in U.S. Pat. No. 4,328,334, and in the J. Chem. Soc. Perkin Trans I, 1986, 1881. In these publications, the product is found denominated as 10-dihydro-10-deoxo-11-azaerythromycin A, and it is obtained by a synthetic sequence which schematically consists of: Obtaining the oxime of erythromycin A (1) by reaction of erythromycin A hydroxylamine hydrochloride. Obtaining the iminoether 9-deoxo-6-deoxy-6,9-epoxy-9,9a-dihydro-9a-azahomoerythromycin A (2) by a transposition of the oxime of erythromycin A (1). This iminoether and the process for obtaining it is also described in Pat. WO 94/26758 and in Eur. Pat. 0,137,132. In U.S. Pat. No. 4,328,324 this iminoether is erroneously assigned the structure of the lactam obtained by a Beckman transposition starting from the oxime of erythromycin. Obtaining 9-deoxo-9a-aza-9a-homoerythromycin A (3) by reduction of the iminoether (2) with sodium borohydride in methanol, or by catalytic hydrogenation in the presence of platinum dioxide with acetic acid as a solvent.
In the literature previously mentioned, the reduction of the iminoether 9-deoxo-6-deoxy-6,9-epoxy-9,9a-dihydro-9a-azahomoerythromycin A (2) can be carried out by following two different methods:
a) Reduction with sodium borohydride in methanol at 0.degree. C. This method presents a number of drawbacks: methanol destroys the reducing agent, and some of the steps which include the isolation of the reaction product (azaerythromycin) affect the quality of the same. The literature previously cited describes how, in the presence of acid aqueous media, azaerythromycin (3) becomes partially hydrolysed to yield deosaminylazaerythromycin (6) (S. Djokic et al. in J. Chem. Soc. Perkin Trans I, 1986, 1881). PA0 b) Catalytic hydrogenation with platinum dioxide, at high pressures (70 atm). The drawbacks of this method, from the point of view of its industrial application are obvious: the high working pressures and the manipulation of platinum dioxide. PA0 a) The dehydrate form keeps its percentile water content constant at values (4,5-5%) which are very close to the theoretical value (4,6%). PA0 b) Thermogravimetric analysis (TGA) of azitromycin dihydrate indicates a total weight loss of between 4,5 and 5% at 200.degree. C., yielding a plot with no inflections throughout the whole process. PA0 c) The differential calorimetry analysis (DSC) of azitromycin dehydrate reveals the presence of a single endotherm which may vary between 126.degree. and 135.degree. C., with an energy absorbed during the process which ranges between 27 and 34 cal/g. PA0 d) The infrared spectra in KBr of both crystalline forms presents clear differences:
The Eschweiler-Clarke reaction employed in U.S. Pat. No. 4,517,359 and in the J. Chem. Res., 1988, 132; and idem miniprint., 1988, 1239, for preparing azitromycin (4) results in the formation of some reaction impurities such as the case of the formamide derived from the amine 9-deoxo-9a-aza-9a-homoerythromycin A.
The structural elucidation studies of azitromycin (4) (S. Djokic and G. Kobrehel J. Chem. Res., 1988, 132; and idem miniprint., 1988, 1239) have demonstrated its existence in two crystalline forms: hygroscopic monohydrate (4) and non-hygroscopic crystalline dihydrate (5). The latter is the preferred form for its manipulation with the object of producing formulations of therapeutic use, as described in the Eur. Pat. No. 0,298,650.

Synthesis of 9-deoxo-9a-aza-11,12-deoxy-9a-methyl-9a-homoerythromycin A 11,12 Hydrogenorthoborate dihydrate and a process for the preparation of azitromicin dihydrate


Techniques for determining a spacing, such as one or more distances, between two or more wellbores formed from a terranean surface to a subterranean formation are described. In some aspects, a wellbore segment is determined for both a first and a second wellbore. One or more distances between the wellbore segments on the first and second wellbores, respectively, is determined. From the determined distance between the wellbore segments on the first and second wellbores, one or more distances between the first and second wellbores may be determined.

Wellbores are formed from the Earth's surface into one or more subterranean zones that are comprised of hydrocarbon-bearing rock formations. Often, multiple wellbores may be formed into the same rock formation or an adjacent rock formation. In some cases, the wellbores are formed too closely together, thereby failing to maximize a hydrocarbon-draining volume of the wellbores relative to their drilling and completion costs. In some cases, the wellbores are formed too far apart, thereby failing to adequately drain the hydrocarbons from the rock formation(s).


A vehicle fluid line for transporting high and low pressure fluids of an engine includes a rigid pipe having opposing ends configured to fixedly couple with the engine. An adjustable joint divides a length of the rigid tube into first and second segments. The adjustable joint has a cylindrical housing coupled with the first segment and having an inner diameter. A stop feature protrudes from an outer diameter of the second segment and interfaces with the cylindrical housing to prevent disengagement of the second segment from the housing. An elastomeric grommet is seated between the inner and outer diameters and is configured to maintain a fluid seal that allows the second segment to rotate axially, pivot radially, and slide longitudinally within the cylindrical housing.

It is generally understood that vehicle engines have various fluid lines, including those that transport oil, coolant, and other potentially high pressure fluids. Typically, high production vehicles utilize flexible hoses that accommodate thermal distortion between components of the engine, as well as production variances that result in inconsistent locations and positions of the connection points for fluid transportation. These flexible hoses can have a relatively high cost and in some cases can have decreased performance near local high temperature heat sources. Alternatively, rigid fluid lines can be difficult to implement in high production vehicles.


A technique of acquiring a width obtaining an appropriate exposure with minimum restrictions, while accurately correcting flickering is provided. An exposure control method includes integrating a video signal obtained by shooting a subject by means of a CMOS imaging element as input video signal over not less than a horizontal period, normalizing the integral value or the difference value of the integral value between neighboring fields or frames, extracting the integral value or the difference value after the normalization as flicker spectrum, determining, based on the extracted flicker spectrum, the presence or absence of a flicker component contained in the video signal obtained by the imaging element and controlling the exposure value, using a program diagram for preferentially employing the shutter speed less liable to produce flickering when it is determined that the video signal contains a flicker component.

The present application relates to an exposure control method and an exposure control apparatus to be used in an image pickup apparatus such as a video camera or a digital still camera including an XY address scanning type imaging element (imager, image sensor), which may typically be a CMOS (complementary metal oxide semiconductor) imaging element, under the lighting of a fluorescent lamp and also an image pickup apparatus.
When an image of a subject is picked up by means of a video camera in direct light from a fluorescent lamp energized by a commercial AC power supply, temporal fluctuations, or so-called flicker, occur in the lightness of the video signal output as a result of the image pickup operation due to the difference between the frequency of luminance change of the fluorescent lamp (change in the quantity of light), which corresponds to twice the frequency of the commercial AC power supply, and the vertical synchronizing frequency of the camera.
For example, when an image of a subject is picked up by a CCD camera of the NTSC system (with the vertical synchronizing frequency of 60 Hz) under the lighting of a non-inverter type fluorescent lamp in a geographical area where the frequency of the commercially supplied AC is 50 Hz, the exposure value of each pixel changes every field as shown in FIG. 1 of the accompanying drawings because of that a field period is 1/60 seconds while the period of luminance change of the fluorescent lamp is 1/100 seconds and hence the timing of exposure of each field is shifted relative to the luminance change of the fluorescent lamp.
Thus, referring to FIG. 1, when the exposure time is 1/60 seconds, periods a1, a2, a3 show different exposure values even if the exposure time is same. When the exposure time is shorter than 1/60 seconds (but not equal to 1/100 seconds for the reason as will be described hereinafter), periods b1, b2, b3 show different exposure values even if the exposure time is same.
The timing of exposure relative to the luminance change of the fluorescent lamp returns to the original one in every three fields and therefore the change of lightness due to the flicker is cyclic and repetitive with a period of three fields. In other words, the luminance ratio of each field (how flickering appears) changes with the exposure period but the period of flicker does not change.
However, the change of lightness in every three frames is repeated with progressive type cameras such as digital cameras when the vertical synchronizing frequency is 30 Hz.
Additionally, a number of different phosphors such as red, green and blue phosphors are normally used in a fluorescent lamp in order to emit white light. However, such different phosphors have respective afterglow characteristics and they emit attenuating light with their respective afterglow characteristics during the period from a stop of electric discharge to the next start of electric discharge that is found in a period of luminance change. Therefore, light that is white at the beginning attenuates, gradually changing the hue, in that period. Then, if the timing of exposure is shifted as described above, there arises not only a change of lightness but also a change of hue. Additionally, since fluorescent lamps have a specific spectral characteristic that a remarkable peak is found at a particular wavelength, the fluctuating components of a signal change from color to color.
Thus, a so-called color flicker phenomenon occurs due to such a hue change and the difference of the fluctuating components from color to color.
On the other hand, if the exposure time is defined to be integer times of the period of luminance change of the fluorescent lamp ( 1/100 seconds) as shown in the lowermost part of FIG. 1, no flicker occurs because a constant exposure value is realized regardless of the timing of exposure.
Actually, there has been proposed a system adapted to detect light being shed from a fluorescent lamp by means of a user's operation or a signal processing operation of the camera and, if light from a fluorescent lamp is detected, set the exposure time to integer times of 1/100 seconds. With such a system, it is possible to fully prevent flickering from taking place by means of a simple technique.
However, it is not possible to select a desired exposure time with such a system so that the degree of freedom of using an exposure adjusting unit of the camera is limited when trying to achieve an appropriate exposure.
Thus, there is a demand for techniques of reducing the flickering of light of a fluorescent lamp regardless of the selected shutter speed (exposure time).
When an image pickup apparatus is so designed that all the pixels are exposed to light at a same timing for an image as in the case of a CCD image pickup apparatus, such a technique can be realized relatively easily because the luminance change and the color change appear only among fields and not in each field.
Referring again to FIG. 1, the flicker changes cyclically and repetitively with a period of three fields if the exposure time is not integer times of 1/100 seconds so that it is possible to suppress the flicker to a level that practically does not give rise to any problem by predicting the current change in the luminance and the colors from the video signal of the field that precedes the current field by three fields and adjusting the gain of the video signal of each field according to the prediction in order to make the average value of the video signals of respective fields.
However, in the case of an XY address scanning type imaging element, which may typically be a CMOS imaging element, the timing of exposure of each pixel is sequentially shifted from that of the preceding pixel in the horizontal direction by a clock (pixel clock) period and hence the timings of exposure of all the pixels differ from each other. In other words, it is not possible to satisfactorily suppress the flicker by means of the above-described technique.
FIG. 2 schematically illustrates this problem. While the timings of exposure of all the pixels differ from each other in the horizontal direction as pointed out above, one horizontal period is sufficiently shorter than the period of luminance change of a fluorescent lamp. Therefore, it is assumed here that the timings of exposure of all the pixels on a horizontal line are same and FIG. 2 shows the timing of exposure of each of the lines arranged in the vertical direction. Such an assumption does not produce any problem in practical applications.
Referring to FIG. 2, in the case of an XY address scanning type imaging element such as a CMOS imaging element, the timing of exposure of each line differ from that of any other line (F1 in FIG. 2 indicates the difference) and hence the exposure value differ from line to line. Then, a luminance change and a color change due to the flicker take place not only among fields but also in each field so that the obtained image shows stripes (that run horizontally and repeat vertically).
FIG. 3 illustrates the flicker in an image when the subject is a uniform pattern. Since the cycle period (wavelength) of stripes is 1/100 seconds, a striped pattern of 1.666 cycle periods is produced in the image. If the number of lines read out per field is M, the number of lines of the striped pattern read out per cycle period is L=M* 60/100. Note that the asterisk (*) is used herein as symbol of multiplication.
As shown in FIG. 4, a striped pattern of five periods (for five times of the wavelength) appears in three consecutive fields (three images). If the fields are viewed successively, the stripes will appear as if they were flowing vertically.
While FIGS. 3 and 4 illustrate only a lightness change due to the flicker, the image quality will in reality be remarkably degraded because a color change additionally takes place. Particularly, the color flicker phenomenon becomes remarkable particularly as the shutter speed rises and the influence of the phenomenon appears in the image picked up by an XY address scanning type imaging element to further degrade the image quality.
If the exposure time can be set to integer times of the cycle period ( 1/100 seconds) of the luminance change of the fluorescent lamp for an XY address scanning type imaging element, the exposure value is held to a constant level so that no flickering of fluorescent lamp, including flickering in the image, takes place regardless of the timing of exposure.
However, if the electronic shutter speed is made variable for a CMOS imaging element, the image pickup apparatus including the CMOS imaging element will become structurally complex. Additionally, if it is not possible to set the exposure time equal to integer times of 1/100 seconds for the purpose of preventing flicking from taking place in an image pickup apparatus having a high degree of freedom for operating an electronic shutter, the degree of freedom of operation of the exposure value adjusting unit for obtaining an appropriate exposure is inevitably reduced.
Thus, there have been proposed techniques of reducing the flickering of fluorescent lamp that is specific to XY address scanning type imaging elements such as CMOS imaging elements.
Patent Document 1 (Jpn. Pat. Appln. Laid-Open Publication No. 2000-350102) and Patent Document 2 (Jpn. Pat. Appln. Laid-Open Publication No. 2000-23040) describe methods of estimating the flicker component by metering the quantity of light of a fluorescent lamp by means of a light receiving element or a light metering element and controlling the gain of the video signal from an imaging element according to the result of the estimation.
Patent Document 3 (Jpn. Pat. Appln. Laid-Open Publication No. 2001-16508) described a method of picking up two images of different types by means of an imaging element under two different conditions, including a first conditions of a first electronic shutter value suitable for the current external lighting condition and a second condition of a second electronic shutter value having a predetermined relationship with the flickering cycle period of a fluorescent lamp, estimating the flicker component by comparing the signals of the two images and controlling the gain of the video signal from the imaging element according to the result of the estimation.
Patent Document 4 (Jpn. Pat. Appln. Laid-Open Publication No. 11-164192) describes a method of storing information on how the lightness changes under the lighting of a fluorescent lamp in a memory in advance as a correction coefficient, while detecting the phase of the flicker component from the video signal obtained from an imaging element by utilizing the difference of frequency between the video signal component and the flicker component, and correcting the video signal by means of the correction coefficient stored in the memory according to the result of the detection.
Patent Document 5 (Jpn. Pat. Appln. Laid-Open Publication No. 2000-165752) describes a method of computationally determining a correction coefficient from two video signals obtained by two exposures carried out with a time difference for inverting the phase of flickering exactly by 180° and correcting the video signal from an imaging element by means of the computationally determined correction coefficient.
However, the methods of estimating the flicker component by metering the quantity of light of a fluorescent lamp by means of a light receiving element or a light metering element as described in the Patent Documents 1 and 2 increase the size and the cost of the system of the image pickup apparatus because a light receiving element or a light metering element has to be added to the image pickup apparatus.
The method of picking up two images of different types under two different shutter conditions and estimating the flicker component as described in the Patent Document 3 is also accompanied by a drawback of making the system of the image pickup apparatus a complex one. Additionally, this method is accompanied by an additional drawback of not suitable for picking up moving images.
The method of using the prepared coefficient that is stored in a memory as correction signal as described in the Patent Document 4 is accompanied by a drawback that it is not possible to reliably detect and reduce the flicker component depending on the types of fluorescent lamp because it is not possible to prepare correction coefficients for all the types of fluorescent lamp. Additionally, with the method of the Patent Document 4 of extracting the flicker component from the video signal, utilizing the difference of frequency between the video signal component and the flicker component, it is difficult to detect the flicker component, discriminating it from the video signal component in the black background part and the low illuminance part of an image where the flicker component is very small, and the performance of detecting the flicker component is degraded remarkably when one or more than one moving objects exist in the image.
Finally, the method of picking up images of two different types at different timings to estimate the flicker component as described in the Patent Document 5 makes the system of the image pickup apparatus complex and is not suited for picking up moving images as in the case of the method of the Patent Document 3.
As described in Patent Document 6 (Jpn. Pat. Appln. Laid-Open Publication No. 2004-222228), the applicant of the present patent application proposed a method of highly accurately detecting the flicker of a fluorescent lamp that is observed specifically by XY address scanning type imaging elements such as CMOS imaging elements by means of a simple signal processing operation without using a light receiving element regardless of the subject, the video signal level and the type of fluorescent lamp to reliably and satisfactorily reduce the flicker.
With the flicker reducing method of the above cited document, the signal components other than the flicker component is removed with normalized integral value or normalized difference value so that, regardless of the subject, it is possible to obtain a signal with which the flicker component can be highly accurately estimated even in the black background part and the low illuminance part of an image where the flicker component is very small. Then, it is possible to highly accurately estimate the flicker component, regardless of the type and the waveform showing a luminance change of the fluorescent lamp, by extracting the spectrum up to an appropriate degree of the normalized integral value or normalized difference value. Thus, it is possible to reliably and satisfactorily reduce the flicker component from the input video signal by computationally operating the estimated flicker component and the input video signal.
Meanwhile, the flicker of a fluorescent lamp in the form of horizontal stripes that arises in XY address scanning type image pickup apparatus shows different characteristics depending on the relation between the frequency of the supplied power and the field or frame frequency of the broadcasting system. For example, it will be found by comparing the characteristics of the stripes that appear in the image that the stripes vary from image to image in terms of frequency, wavelength, waveform and amplitude. It will also be found by comparing a plurality of images among fields that the cyclicity of stripes also varies. FIGS. 5A through 5D illustrate how the cyclicity of stripes varies. When an image pickup operation is conducted by means of the NTSC system under the lighting of a fluorescent lamp in a geographical area where the frequency of the commercially supplied AC is 50 Hz, the flicker stripes show a cyclicity of three fields as shown in FIG. 5A because the imaging cycle period and the power supply cycle period regain the original phase relationship in every three field. Then, when the picked up image is viewed continuously, horizontal stripes appear as if they were flowing vertically. A similar phenomenon appears when an image pickup operation is conducted by means of the PAL system under the lighting of a fluorescent lamp in a geographical area where the frequency of the commercially supplied AC is 60 Hz. In this case, flicker stripes appear as if they were flowing vertically with a cyclicity of five fields as shown in FIG. 5B. The technique proposed in the Patent Document 6 (Jpn. Pat. Appln. Laid-Open Publication No. 2004-222228) separates the image component and the flicker component by utilizing the cyclicity of flicker stripes that appear among fields and extracts the flicker component from the frequency spectrum thereof to correct the gain by using the extracted flicker component. This technique is very effective for the problem of flickering of fluorescent lamp that shows such "inter-field cyclicity".
On the other hand, no flicker stripe appears when an image pickup operation is conducted by means of the NTSC system under the lighting of a fluorescent lamp in a geographical area where the frequency of the commercially supplied AC is 60 Hz or by means of the PAL system under the lighting of a fluorescent lamp in a geographical area where the frequency of the commercially supplied AC is 50 Hz. Horizontal stripes of flicker appear by the same token when the shutter is operated at high speed with either of the above listed combinations of the broadcasting system and the power supply frequency. However, with either of the above listed combinations, the relative relationship between the imaging cycle period and the power supply cycle period is conclusive within a single field as shown in FIGS. 5C and 5D so that, when the picked up image is viewed continuously, horizontal stripes do not appear as if they were flowing vertically. In other words, flicker stripes that arise with either of the above listed combinations differ remarkably from flicker strips that arise with the combinations described in the preceding paragraph because they constantly appear at the same positions. Thus, with the algorithm of the technique described in the Patent Document 6 (Jpn. Pat. Appln. Laid-Open Publication No. 2004-222228) that utilizes the "inter-field cyclicity", it is no longer possible to discriminate flickers from the subject with either of the combinations. Then, it is no longer possible to remove or alleviate flickers with that technique. Many flicker correcting techniques that have hitherto been proposed utilize the "inter-field cyclicity" but are accompanied by the same problem that their algorithms are reduced totally ineffective with those combinations.
This problem can be avoided by tactfully selecting the shutter speed. No flicker stripes appear when n/100 seconds (where n is a natural number) in the case of FIG. 5A or 5C or n/120 seconds in the case of FIG. 5B or 5D is selected for the shutter speed regardless of the timing of exposure. The relationships between the shutter speed and the frequency of the supplied power are summarily listed in FIG. 6.
However, the above-described arrangement reduces the degree of freedom of the exposure adjusting unit for realizing an appropriate exposure because the shutter speed is fixed to n/100 seconds or n/120 seconds. It will not be allowed to discard the freedom of exposure adjustment simply to avoid the flicker problem. There arises an additional problem that some unit is necessary to estimate the frequency of the supplied power. For example, the frequency of the supplied power may be determined from the relationship between the cycle period of flicker stripes and the frame rate. However, when the flicker stripes do not move, it is not possible to determine if the stripes appearing in the video signal are produced by flickering or belong to the subject. While this problem can be avoided by using an external sensor, the use of such a sensor is accompanied by a problem of cost and size. Additionally, since the "inter-field cyclicity" is determined according to information coming from the image pickup apparatus, a problem of post-detection can arise when information on the angle of view changes due to framing or some other reason. Then, the most reliable technique for avoiding flicker stripes may be that of fixing the shutter speed to n/100 seconds or n/120 seconds rather than the technique of the Patent Document 6 (Jpn. Pat. Appln. Laid-Open Publication No. 2004-222228).

Exposure control method, exposure control apparatus and image pickup apparatus