Convolutionally encoding a data stream includes inputting a first block of two or more bits in parallel into a shift register. A number of intermediate calculations are performed in parallel using a number of respective delayed shift register outputs; and said number of intermediate calculations are output to form a convolutionally encoded sequence.

The fundamental concepts and mathematical theory of information transmission were developed and described by C. E. Shannon many years ago. Shannon perceived that it was possible to transmit digital information over a noisy channel with an arbitrarily small error probability by employing appropriate channel encoding and decoding.
The goal of approaching such error-free transmission can be achieved when the information transmission rate is less than the channel capacity, in bits per second. Since Shannon's work, a great deal of effort has been exerted by many researchers to find better and more efficient coding and decoding methods for error control. As a result, many different types of codes, primarily block codes and convolutional codes, have been developed and used in modern digital communication systems.
Block codes are implemented by combination logic circuits, examples of which include: Reed-Muller (RM) codes, cyclic codes, array codes, single-error-correcting (SEC) Hamming codes, and Reed-Solomon (RS) codes.
Convolutional codes are implemented by sequential logic circuit and are also called tree codes or trellis codes. In general, block and convolutional codes can be binary or non-binary, linear or non-linear, and systematic or nonsystematic. At the receiving end, the channel decoder uses any redundancy in the channel code sequence to correct errors, if there are any, in the received channel sequence. The decoder then produces an estimate of the source information sequence.
Modern digital communication systems have evolved to the extent that they now often require error-free recovery of transmitted data. Errors, caused by signal distortion, are introduced into wireless transmitted signals primarily due to multi-path and fading effects. Furthermore, cellular radio technology attempts to maximise use of the limited channel bandwidth by reusing the available frequencies in different cells. As a result, cellular radio systems also suffer from significant co-channel and adjacent channel interference in addition to the effects of multipath and fading.
The errors/distortion introduced into wireless transmitted signals result in received bits being wrongly decoded. Hence, the issue of data integrity, where error protection is required or desired, is therefore becoming increasingly important. To offer some protection against such distortion effect, channel coding is used.
A channel-coding scheme may typically include such techniques as cyclic redundancy checking, convolutional encoding and interleaving. Convolutional encoding introduces redundancy into the data to be transmitted by effectively spreading out the information contained in each bit. The use of convolutional encoding, together with Viterbi decoding, enables some of the bits received in error to be corrected. Hence, efficient and effective error-correcting codes are therefore highly desirable, particularly in a wireless communication system.
A convolutional code depends not only on the last information frame, but also on n preceding information frames. As a consequence, convolutional encoding is known to require a relatively large number of simple computations. A typical convolutional encoding scheme is defined in the GSM EDGE standard ["GSM 05.03 v8.3.0 (2000-02): "Digital Cellular Telecommunications System (Phase 2+); Channel Coding"].
The scheme is defined by:                (i) Its rate (r), which is 1/3 (meaning 3 results are output for each input),        (ii) Its constraint length (K), which is 7, and        (iii) Its polynomials, which are:y(3k)=D0⊕D2⊕D3⊕D5⊕D6  [1]y(3k+1)=D0⊕D1⊕D2⊕D3⊕D6  [2]y(3k+2)=D0⊕D1⊕D4⊕D6  [3]         where:                    K is the constraint length of the convolutional encoding scheme,            k—indexes 'k' input bits,            y(k) is output data,            Dn=x(k−n), x(k) is input data, and            ⊕ represents modulo-two addition, or the exclusive-or operation.
The GSM/Edge coding scheme can be represented as a shift register configuration 100, as shown in FIG. 1. A sequence of bits x(k) is input to a series of shift registers 115 to 145 for successively transferring the bit sequence. The output sequence can then be obtained by combining appropriately shifted bits output from the shift registers with the eleven binary adders 160 as shown, to provide the three output polynomials 170, 175, 180 as illustrated in equations [1] to [3].
The input-output function of this shift-register sequence is linear (as only linear elements are involved) and time-invariant: a delay of one shift at the input causes a delay of three shifts at the output. Thus, we get a convolutional (3,1)-code.
A key factor in the implementation of convolutional coding schemes is how to implement the theory in an efficient and effective processing manner. The performance capabilities and use of digital signal processors (DSPs) is continually increasing, as applications become more complex. Wireless communications is one such application.
DSPs now include the use of multi-core devices, co-processors and devices with single or multiple arithmetic login units (ALUs). The modern architectures of these devices allow independent calculations to be performed in parallel, thus prompting new approaches when implementing traditional DSP-related functions.
In addition, it is known that assembly language programming is a time-consuming process. For equipment manufacturers, assembly language programming potentially leads to increased time to market as well as difficult maintenance. These problems are compounded in modern multi-ALU devices with their complex architectures.
Fortunately, recent increases in processor performance and advancing compiler technology now make it feasible to implement most DSP functionality in a programming language such as 'C'. Despite ever-improving compiler technology it is still necessary for the programmer to use knowledge of the application and the device to make maximum use of the parallel processing capability available.
A need therefore exists for an efficient convolutional encoder configuration wherein the abovementioned disadvantages may be alleviated.

Convolutional encoder and method of operation

Abstract: In one example, a register (of individual bits stored in words), is set up. The register is longer than the constraint length means that a relatively large number of input bits can be read from memory only once, thus avoiding many independent moves of operands to and from memory. Since the register is longer than the constraint length, the register need only be shifted once for every ‘a+1’ input bits, rather than once for each bit.


Method and system are offered which evacuate a sample holder such that a sample can be inserted into the electron optical column of a microscope while certainly preventing exposure to the atmosphere. The system has pumping control means for controlling a vacuum pumping sequence. The inside of a microscope goniometer is evacuated to a given low vacuum state while the pressure inside a hermetic sample chamber is kept constant by the pumping control means. Then, the partition valve of the sample chamber is opened by the pumping control means and the sample chamber is brought to the low vacuum state. Then, the goniometer and sample chamber are brought to a high vacuum state by the pumping control means. Then, the sample is brought into the front end of the goniometer, and the sample holder is inserted into the electron optical column.

1. Field of the Invention
The present invention relates to a method and system for evacuating a sample holder and, more particularly, to a method and system for evacuating a sample holder in such a way that a hermetic chamber can be connected to the inside of a goniometer under an evacuated state without replacing the insides of the goniometer and of the sample holder by an inert gas and that a sample can be inserted into the electron optical column of a microscope while reliably preventing exposure to the atmosphere.
2. Description of Related Art
A sample held on a sample holder is inserted into position within an electron microscope and irradiated with an electron beam. Then, charged particles and X-rays emanating from the sample are detected. Thus, the shape or composition of the sample can be estimated. In this situation, in a case where materials mainly containing a material such as a battery material that should be kept out of the atmosphere are analyzed, it is necessary that the sample holder be reliably inserted into the electron optical column of a microscope. Especially, in a case of a battery material that should be prevented from being exposed to the atmosphere, it is necessary to insert the sample into the electron optical column of the electron microscope in such a way that the sample is not exposed to the atmosphere.
FIGS. 6A-6H show a conventional sequence of steps for mounting a sample holder to a goniometer.
Referring to FIG. 6A, there are shown a glove box 1, a hermetic sample chamber 2 disposed in the box 1, a sample 3 placed at the front end of a rod 9, leaf springs 6 having front-end portions gripping the sample therebetween, a seal cap 4, a leak valve 5 mounted at one end of the seal cap 4, a knob 8, and seals 7. The rod 9 has a front-end portion on which the sample 3 is held. The sample 3 and the leaf springs 6 together form a sample holding portion. The sample holding portion and the rod 9 together form a sample holder. The inside of the glove box 1 is maintained in a vacuum or filled with an inert gas.
The rod 9 is used to transport the whole sample holding portion. The sample holder portion is transported into the hermetic chamber by manipulating the knob 8 attached to the rod 9. The sample is kept isolated and shut off from the outside atmosphere by sealing off the hermetic sample chamber 2 with a partition valve 11. The seal cap 4 seals the front end of the sample holder to thereby isolate the sample holding portion from the atmosphere if it is located at the front end of the holder. The seal cap 4 has the leak valve 5 mounted thereon and can place the inside of the cap 4 into communication with the outside atmosphere according to the need. When the microscope sample 3 is placed on the sample holding portion, the sample 3 is held by being sandwiched between the ancillary leaf springs 6.
The microscope sample 3 is held in the sample holding portion by the leaf springs 6 and thus placed in position within the glove box 1.
Referring to FIG. 6B, the seal cap 4 is attached at the front end of the holder, and the leak valve 5 of the cap 4 is closed. Under this condition, the partition valve 11 of the hermetic sample chamber 2 is kept open.
Referring to FIG. 6C, the sample holder is taken into the atmosphere out of the glove box 1 together with the whole seal cap 4. Then, the front-end portion of the sample is moved into the hermetic holder/sample chamber 2 with the knob 8. Subsequently, the partition valve 11 is closed to seal off the hermetic sample chamber 2. In particular, the sample 3 can be brought into the hermetic sample chamber 2 by moving a rod 15 holding the sample through the hermetic inside of the rod 9 to the right as viewed in the figure. As a result, the inside of the hermetic sample chamber 2 can hold the sample 3, and can be maintained as a vacuum or filled with an inert gas.
Referring to FIG. 6D, the leak valve 5 of the seal cap 4 is loosened such that the sample holder other than the hermetic sample chamber 2 is vented to the atmosphere. Then, the seal cap 4 is removed. Consequently, only the hermetic sample chamber 2 is held in a vacuum or inert gas ambient.
Referring to FIG. 6E, the sample holder is manually set into an electron microscope goniometer 15 and preliminary pumping is done, the goniometer 15 being mounted to the electron optical column 20 as shown.
Referring to FIG. 6F, the inside of the goniometer 15 is once vented and filled with nitrogen gas.
Referring to FIG. 6G, the partition valve 11 is opened and the sample 3 is moved into the front-end portion. Preliminary pumping is again performed, and the sample holder is inserted into the electron optical column 20. In this case, the sample 3 can pass through the goniometer 15.
Referring to FIG. 6H, the user performs a microscopic examination using the electron microscope. That is, an electron beam is directed at the sample 3. Secondary electrons, backscattered electrons emitted from the sample 3 or electrons transmitted through the sample 3 are detected.
FIG. 7 is a flowchart illustrating a pumping sequence for a conventional goniometer. This sequence is now described by referring also to FIGS. 6A-6H. First, all the partition valves are closed. Pumping of the goniometer 15 is started (S1). Then, pumping using an oil-sealed rotary pump and an oil diffusion pump is initiated (S2). The partition valve of the oil-sealed rotary pump is opened to start pumping using the rotary pump (S3). Then, a decision is made as to whether the degree of vacuum in the goniometer has reached a level at which pumping using the oil diffusion pump is needed (S4). If the level is not reached, the pumping using the oil-sealed rotary pump is continued.
When the degree of vacuum has reached a level at which pumping using the oil diffusion pump is required owing to the pumping using the oil-sealed rotary pump, the partition valve of the oil-sealed rotary pump is closed (S5). Then, the partition valve of the oil diffusion pump is opened (S6). A decision is made as to whether the degree of vacuum in the goniometer 15 has reached a level at which the pumping is complete (S7). If the pumping is not complete, the pumping using the oil diffusion pump is continued. If the degree of vacuum in the goniometer 15 has reached the level at which the pumping is complete, the pumping of the goniometer 15 is terminated (S8). At this stage, all the partition valves are closed.
One known apparatus of this type is described, for example, in JP-A-2010-61990 (paragraph 0025; FIGS. 4 and 5) and has a sample chamber in which a sample to be irradiated with an electron beam is disposed and gas inlet/exit piping including an inlet pipe for introducing gas into the sample chamber and an exit pipe for discharging gas from the sample chamber. One of the inlet and exit pipes surrounds the outer periphery of the other. The inlet and exit pipes have an increased cross section to increase the conductance for introduction and discharge of the gas.
A technique using a sealing block having a membrane-type gas ambient sample chamber is known and described, for example, in JP-A-2009-117196 (paragraph 0029; FIG. 1). The sealing block is supported by a pair of Y rotary shafts and bearings. The Y rotary shafts are located coaxially on the Y-axis. The sealing block consists of a gas supply tube forming a gas passage, a gas discharge tube, holes accepting the shafts, and a sample holder configured to hold the membrane-type gas ambient sample chamber. The sealing block can be hermetically tilted about the Y-axis.
The prior art techniques have the following problems.
1) Main battery materials to be analyzed are often crystalline. When they are observed with an electron microscope, accurate crystallographic adjustments are required. With the prior art techniques, tilting only about the X-axis is allowed. Therefore, it is impossible to tilt the sample exactly in the desired crystallographic orientation.
2) In the prior art techniques, the material of the front end of the sample holding portion is phosphor bronze that can be a background source when an energy dispersive X-ray analysis is performed. Therefore, undesired X-rays are produced, which is unsuited for energy dispersive X-ray analysis.
3) In the prior art techniques, when the insides of the goniometer and of the front-end portion of the holder are once replaced with an inert gas after the insides are pumped down, it is necessary to manipulate a switch plural times. During this time, there is the danger that an erroneous operation will take place, exposing the sample to the atmospheric gas temporarily.

Method of evacuating sample holder, pumping system, and electron microscope


A method of tracking faces in an image stream with a digital image acquisition device includes receiving images from an image stream including faces, calculating corresponding integral images, and applying different subsets of face detection rectangles to the integral images to provide sets of candidate regions. The different subsets include candidate face regions of different sizes and/or locations within the images. The different candidate face regions from different images of the image stream are each tracked.

1. Field of the Invention
The present invention provides an improved method and apparatus for image processing in acquisition devices. In particular the invention provides improved real-time face tracking in a digital image acquisition device.
2. Description of the Related Art
Face tracking in digital image acquisition devices includes methods of marking human faces in a series of images such as a video stream or a camera preview. Face tracking can be used to indicate to a photographer the locations of faces in an image, thereby improving acquisition parameters, or allowing post processing of the images based on knowledge of the locations of the faces.
In general, face tracking systems employ two principle modules: (i) a detection module for locating new candidate face regions in an acquired image or a sequence of images; and (ii) a tracking module for confirming face regions.
A well-known fast-face detection algorithm is disclosed in US 2002/0102024, hereinafter referred to as "Viola-Jones", which is hereby incorporated by reference. In brief, Viola-Jones first derives an integral image from an acquired image, which is usually an image frame in a video stream. Each element of the integral image is calculated as the sum of intensities of all points above and to the left of the point in the image. The total intensity of any sub-window in an image can then be derived by subtracting the integral image value for the top left point of the sub-window from the integral image value for the bottom right point of the sub-window. Also, intensities for adjacent sub-windows can be efficiently compared using particular combinations of integral image values from points of the sub-windows.
In Viola-Jones, a chain (cascade) of 32 classifiers based on rectangular (and increasingly refined) Haar features are used with the integral image by applying the classifiers to a sub-window within the integral image. For a complete analysis of an acquired image, this sub-window is shifted incrementally across the integral image until the entire image has been covered.
In addition to moving the sub-window across the entire integral image, the sub window is also scaled up/down to cover the possible range of face sizes. In Viola-Jones, a scaling factor of 1.25 is used and, typically, a range of about 10-12 different scales are used to cover the possible face sizes in an XVGA size image.
The resolution of the integral image is determined by the smallest sized classifier sub-window, i.e. the smallest size face to be detected, as larger sized sub-windows can use intermediate points within the integral image for their calculations.
A number of variants of the original Viola-Jones algorithm are known in the literature. These generally employ rectangular, Haar feature classifiers and use the integral image techniques of Viola-Jones.
Even though Viola-Jones is significantly faster than previous face detectors, it still involves significant computation and a Pentium-class computer can only just about achieve real-time performance. In a resource-restricted embedded system, such as a hand held image acquisition device, e.g., a digital camera, a hand-held computer or a cellular phone equipped with a camera, it is generally not practical to run such a face detector at real-time frame rates for video. From tests within a typical digital camera, it is possible to achieve complete coverage of all 10-12 sub-window scales with a 3-4 classifier cascade. This allows some level of initial face detection to be achieved, but with undesirably high false positive rates.
In US 2005/0147278, by Rui et al., which is hereby incorporated by reference, a system is described for automatic detection and tracking of multiple individuals using multiple cues. Rui et al. disclose using Viola-Jones as a fast face detector. However, in order to avoid the processing overhead of Viola-Jones, Rui et al. instead disclose using an auto-initialization module which uses a combination of motion, audio and fast face detection to detect new faces in the frame of a video sequence. The remainder of the system employs well-known face tracking methods to follow existing or newly discovered candidate face regions from frame to frame. The method described by Rui et al. involves some video frames being dropped in order to run a complete face detection process.
U.S. Pat. No. 6,940,545 to Ray et al., which is incorporated by reference, describes the use of face detection to adjust various camera parameters including Auto-Focus (AF), Auto-Exposure (AE), Auto White Balance (AWB) and Auto Color Correction (ACC). The detection algorithm employed by Ray et al. is a two part algorithm wherein the first stage is fast, but exhibits a high false positive rate and the second stage is more accurate but requires significantly more processing time.
In particular, Ray et al state that the face detector must operate on an image in a timeframe of less than one second (col. 10, line 57) although they do not specify if this timeframe is for the combination of fast and accurate detectors or is a limit on the fast detector only. Where a detection or combined detection/tracking algorithm is applied to preview images in a state-of-art camera, it typically operates on a timeframe of 20-30 ms in order to be compatible with preview frame rates of 30-50 fps. This is a significantly faster requirement than any capability specified in Ray et al.
Ray et al also describe the use of a "framing image" (e.g. FIG. 3), which may be deemed somewhat analogous to a preview image within a state-of-art camera. However, the concept of tracking face regions from frame to frame within a stream (or collection) of (low-resolution) preview images is not described by Ray et al. Also, U.S. Pat. No 7,269,292, which is incorporated by reference, contains the concept of tracking a face region within a collection of low resolution images and using this information to selectively adjust image compression.
Disadvantages of the processes described by Ray et al., include the following: First, using a color based fast face detector is actually quite unreliable as many backgrounds and scene objects can be confused with skin colors. Second, the face detector of Ray et al. is applied to an entire scene before any additional processing occurs. This can lead to a time lag of one second plus the time to implement processes such as auto-focus, auto-exposure or auto white balance. Third, Ray et al. only described to adjust camera parameters responsive to a user activating an acquisition, whereas in a practical camera it is desirable to constantly adjust exposure, focus and color balance based on each frame of a preview stream. Fourth, where image acquisition is asynchronous with respect to the preview stream, then Ray et al. apply face tracker processing to the current frame completely before the rest of the method described by Ray et al. is applied.

Face tracking for controlling imaging parameters

DigitalOptics Corporation Europe Limited


An attachment for a ladder includes a housing and an extensible leg. The housing is clamped to the side of a ladder, and the extensible leg is extended to engage the ground after the ladder has been placed level. A bubble level is provided for visually determining when the ladder is level.

Attachments for a ladder which provide an extendable leg are known. For example, U.S. Pat. Nos. 1,177,069 (Verow), 2,555,036 (Husted), 2,783,928 (Cox), 2,911,134 (Derby), 2,914,135 (Crouch), and 4,627,515 (Studer) show various arrangements which provide an extensible leg for holding a ladder level on an uneven surface. Some of these are removably attached to the ladder while others are permanent parts of the ladder structure.
It is also known to provide a ladder with a bubble level to indicate when the ladder is in a desired orientation. For example, U.S. Pat. Nos. 2,845,719 (Thomiszer) and 4,554,994 (Weiner) show bubble levels for indicating when a ladder is leaning at a proper angle against a wall.


The object of the present invention is to provide an optical module for the WDM communication system, in which the oscillation wavelength is on the grid of the WDM regulation, moreover the optical output power and the oscillation wavelength can be controlled independently. The present module comprises a semiconductor light-emitting device, a wedge shaped etalon device and two light-receiving devices. The etalon device contains a first portion, on which the anti-reflection films are coated, and a second portion. One of the receiving devices detects light transmitted through the first portion of the etalon device, while the other device detects light through the second portion. Signal from the former device controls the output power of the light-emitting device, while the signal from the latter receiving device controls the oscillation wavelength of the laser.

1. Field of Invention
This invention relates to an optical module, especially relates to an optical signal source used in a WDM (Wavelength Division Multiplexing) communication.
2. Related Prior Art
In the WDM communication, the wavelength interval to the adjacent channel is defined to be 0.8 nm. This regulation means that the absolute accuracy superior than ±/−0.1 nm is required for the signal wavelength of respective channel. A semiconductor laser, such as DFB laser diode (Distributed Feedback Laser) and DBR (Distributed Bragg Reflector), is utilized for the signal source of the WDM system.
These feedback lasers have a sharp oscillation spectrum with a typical bandwidth less than 50 GHz. However, since the Bragg grating formed within a laser diode chip solely determines the oscillation wavelength, it would be quite difficult to get the desired wavelength due to the uncertainty of the manufacturing process parameter.
It is also known that the oscillation wavelength of individual lasers can be adjusted by the feedback control after the completion of the production. The method is: 1) dividing the output light from the optical module, 2) monitoring the divided light with a spectrum analyzer, and 3) adjusting the temperature of the laser diode and the injection current to the laser, thus controlling the oscillation wavelength. However, this technique uses the optical spectrum analyzer and is quite impossible to apply to the WDM system, which requires a plurality set of such large-scale equipment for respective optical signal source.
Another example is disclosed in U.S. Pat. No. 5,825,792, in which a parallel plates etalon device is used for the controlling of the oscillation wavelength. In the '792 patent, two optical detectors monitor a divergent light emitted from the back facet of the laser diode through the etalon device placed with an angle for the light. By feed backing the differential signal of two detectors to a temperature of the laser, the oscillation wavelength is effectively adjusted. This method realizes the precisely controlled oscillation wavelength, but requires a precisely adjustment of the rotational angel of the etalon device to the divergent light beam of the laser.


A transition strip is used to install, replace, and repair a floor panel in a floating floor system. The transition strip is a film or tape that comprises plastic, vinyl, polyvinyl chloride, polyester, polyolefin, or nylon. The transition strip can be used to repair a floor panel by removing at least one of the floor panels in the floating floor system to form an opening therein. The transition strip is positioned in the opening such that a portion of a top side of the transition strip adheres to a bottom surface of a bottom layer of at least one floor panel adjacent the opening and a portion of a top side of the transition strip extends into the opening. A bottom surface of a bottom layer of a replacement floor panel is then adhered to the portion of the transition strip extending into the opening.

Floor panels for use in floating floor systems typically comprise a top layer and a bottom layer adhered together in an offset relationship such that a substantially L-shaped marginal end portion of a top surface of the bottom layer and a substantially L-shaped marginal end portion of a bottom surface of the top layer are exposed. The top layer typically comprises at least one mix layer, a print film, a wear layer, and a top coat. The bottom layer typically comprises at least one mix layer. The bottom layer has a thickness about equal to or greater than the top layer. A ratio of a thickness of the top layer to a thickness of the bottom layer is typically in the range of about 2 or less. For example, the SURFACE SOURCE product sold by Lowe's Home Centers, Inc. has a top layer with a thickness of about 64 mils (about 1.63 millimeters), and a bottom layer with a thickness of about 61 mils (about 1.55 millimeters). Thus, the ratio of the thickness of the top layer to the bottom layer is about 1.05 (64 mils/61 mils=1.05).
In order to assemble the floating floor system, at least one of the marginal end portions of each of the floor panels is provided with an adhesive. The marginal end portion provided with the adhesive is engaged with the marginal end portion of an adjacent floor panel to form the floating floor system. Because the thickness of the bottom layer is significantly large (about 98 mils (about 2.5 millimeters)), installation, replacement, and repair of the floor panels can be difficult and labor intensive. For example, when the floor panels are installed, if a gap is formed between the ends of the bottom layers of the adjacent floor panels, the gap can telescope through the floor panels thereby significantly altering the aesthetic and structural characteristics of the top layer. Additionally, if the ends of the bottom layers of the adjacent Hoof panels are caused to overlap, the overlaps can additionally telescope through the floor panel thereby also significantly altering the aesthetic and structural characteristics of the top layer.
Additionally, in order to repair a floor panel in a floating floor system having the above-described characteristics, a cutting mechanism must be guided about the perimeter of the top layer. As the cutting mechanism is guided about the perimeter of the top layer, the cutting mechanism must be forced to additionally cut through the bottom layer of the floor panel. Because the bottom layer is a thick mix layer, cutting through the bottom layer is extremely difficult. The floor panel is then pried up and removed from the floating floor system to create an opening in the floating floor system. Because the bottom layer is cut in a position corresponding to the perimeter of the top layer, a portion of the bottom layer remains underneath the adjacent floor panels when the floor panel is removed from the floating floor system. Thus, due to the thickness of the bottom layer, the bottom layer remaining underneath the adjacent floor panels must be completely carved out before a replacement floor panel can be inserted into the opening and adhered to the adjacent floor panels.
In view of the foregoing, there still remains a need to develop a method of installing, replacing, and repairing floor panels that overcomes the above-described problems.

Transition strip for floor panel and method of installation, replacement, and repair using the same


A method for generating radiation with stabilized frequency, comprises the steps of providing laser light pulses with a repetition frequency fR, said pulses comprising a plurality of N frequency components fn with fn=n fR+f0, wherein f0 represents an offset frequency with n=1 , . . . , N, said frequency components forming a comb with first and second different frequency portions, and generating a primary light output with at least one output frequency component corresponding to the difference of frequencies of said first and second frequency portions.

The invention relates to a method for generating radiation with stabilized frequency, in particular a method for generating stabilized frequencies in the range from radio frequencies up to optical frequencies, and to a device for generating radiation with stabilized frequency, e.g. a stabilized laser generator.
The generation of short light pulses (typical pulse widths in the range down to ps or fs) with laser sources is generally known for many years. As an example, light pulses are generated by locking of oscillation modes of the light field in the laser resonator (mode locking). The light pulses are emitted as a periodic pulse train with a pulse-pulse-distance or repetition time T=fRxe2x88x921 (see FIG. 1). The repetition time is determined by the length L of the laser cavity and the mean group velocity of the pulses Vgr according to T=2L/Vgr. The consideration of the pulses in the frequency domain yields a frequency comb with a mode structure illustrated in the lower part of FIG. 1. The frequency comb comprises a series of frequency components according to the number of oscillation modes contributing to the pulse formation. The distance of the frequency components equals the repetition frequency fR.
Due to the difference between the phase velocity of the single frequency components and the group velocity associated with the pulses, a phase shift xcex94xcfx86 appears causing a shift of the absolute frequencies fN of the components according to fN=n fR+f0 with f0=xcex94xcfx86/T2xcfx80. The repetition frequency fR and the offset or slip frequency f0 represent two degrees of freedom of the frequency comb.
For current applications of laser light, in particular ultra-short light pulses, e.g. in the fields of spectroscopy, telecommunication and time measurement, highly stabilized optical frequencies and pulse parameters are required. While the repetition frequency fR can be measured and controlled by adjusting the cavity length of the laser resonator, offset frequency f0 requires particular control techniques.
T. Udem et al. (xe2x80x9cPhys. Rev. Lett.xe2x80x9d, vol. 82, 1999, p. 3568) disclose the stabilization of frequency combs by introducing a linear dispersion into the resonator. This technique allowing a control and stabilization of the offset frequency f0, suffers from the following disadvantage. The control of the first order dispersion in the cavity requires a sensitive measurement and adjustment system which is difficult to be handled under practical conditions, e.g. in a routine spectroscopic measurement arrangement or in a pulse source for telecommunication applications.
The object of the invention is to provide an improved method for generating radiation with stabilized frequency.
It is another object of the invention to provide an improved radiation source for generating radiation with stabilized frequency, e.g. a stabilized laser light or microwave generator.
The method for generating radiation with stabilized frequency comprises the steps of providing laser light pulses with a repetition frequency fR, the pulses comprising a plurality of N frequency components fn with fn=nxc2x7fn+f0, wherein f0 represents an offset frequency with n=1, . . . , N, the frequency components forming a comb with first and second different frequency portions, and generating a primary light output with at least one output frequency component corresponding to the difference of frequencies of the first and second frequency portions
According to one embodiment of the invention, the first and second different frequency portions are delivered directly to a difference frequency generator. According to another embodiment, a method for generating radiation with stabilized frequency is provided, wherein the laser light pulses with a repetition frequency fR are subjected to a frequency filter device transmitting radiation comprising first and second filtered portions corresponding to different first and second frequency intervals xcex4f1, xcex4f2, each of the filtered portions comprising at least one frequency component fN,1, fn,2, and the primary light output with at least one output frequency component is generated corresponding to the difference of frequencies of the first and second filtered portions.
The laser light pulses comprise a plurality of N frequency components fn with fn=n fR+f0, wherein f0 represents an offset frequency with n=1, . . . , N. The laser pulses can be produced by any available pulse laser. Preferably, the pulses have a mean pulse width in the range of 10 ps to 10 fs or lower and a repetition frequency fR in the range of 20 MHz to 3 GHz. The primary light output is generated using a non-linear difference frequency generation process being known as such. For obtaining a primary light output with sufficient output power, each of the first and second filtered portions comprise a plurality of frequency components with N=1000 or higher, However, the invention can be implemented with smaller N-values, even with N=1, if cw lasers are phase locked to single frequency modes of the laser pulses (see below) and the frequency difference of the cw laser outputs is provided as the primary light output and/or if the Signal/Noise-Ratio is sufficient high.
An essential advantage of the invention is presented by the fact that the primary light output comprises at least one frequency component or up to M frequency components fm with fm=m fR with m=1, . . . , M. The frequency component(s) (or a mean frequency) are independent of the offset frequency. The non-linear frequency difference process eliminated the offset frequency which is contained in both first and second filtered portions of the laser light pulses. Furthermore, the frequency components fm can be completely adjusted by controlling the repetition frequency of the pulse laser only.
According to a preferred embodiment of the invention, the laser pulses are subjected to non-linear self phase modulation before the filtering for broadening the frequency comb corresponding to the pulses. The broadening preferably is obtained by transmitting said laser light pulses through a non-linear optical element producing further frequency modes, as e.g. an optical fiber. Optical fibers with a strong comb broadening, as photonic crystal fibers (see D. Mogilevtsev et al. in xe2x80x9cOptics Lettersxe2x80x9d, vol. 23, 1998, p. 1662, T. A. Birks in xe2x80x9cOptics Lettersxe2x80x9d, vol. 22, 1997, p. 961, or T. A. Birks in xe2x80x9cIEEE Photonics Lettersxe2x80x9d, vol. 11, 1999, p. 674), are preferably used.
Another subject of the invention is the provision of a radiation source device for generating radiation with stabilized frequency, the radiation source device comprising in particular a laser pulse generator for generating the laser light pulses with a repetition frequency fR, optionally a frequency filtering device for providing the first and second filtered portions, and a non-linear difference frequency generator being adapted to generate a primary light output with at least one output frequency component corresponding to the difference of frequencies of the first and second frequency portions or filtered portions.
According to a preferred embodiment of the radiation source device, a pulse broadening device (e.g. an optical fiber) is arranged between the laser pulse generator and the frequency filtering device.
According to a further preferred embodiment of the invention, a laser or a microwave generator is phase-locked to the primary light output for generating a secondary light output with a stabilized optical or rf frequency, respectively.
A particularly important advantage of the invention results from the broad application range of the generated primary light output. Depending on the laser light pulse width, the first and second filtered portions may have a high frequency distance ranging up to optical frequencies, or a small frequency distance corresponding to radio frequencies, The radiation source device provides an universal frequency generator for a series of applications in time/frequency measurements (e.g. spectroscopy) and in telecommunications.
The invention has the following further advantages. The radiation source device according to the invention has a compact and robust design allowing an easy adjustment and applications under routine conditions. The radiation source device is compatible with conventional laser optical beam forming and measurement techniques.

Method and device for generating radiation with stabilized frequency

Max-Planck-Gesellschaft zur Forderung der Wissenschaften e.V.


A vehicle may include an engine compartment and a fuel cell stack arranged in the engine compartment. The fuel cell stack may include an enclosure having an interior space and a cell disposed in the interior space of the enclosure configured to generate electrical energy. The enclosure may include an enclosure inlet guiding air from an exterior of the enclosure to the interior space, and an enclosure outlet guiding air from the interior space to the exterior. The fuel cell stack may also include a filter preventing foreign matter from being introduced into the interior space of the enclosure arranged in the enclosure inlet. The filter may include a filter member covering the enclosure inlet and a filter cover covering the filter member. The filter cover may include a filter cover inlet guiding air to the filter member. The filter cover inlet may fluidically communicate with the engine compartment.

Generally, a fuel cell is a device that directly converts chemical energy stored in a fuel into electrical energy by an electrochemical reaction.
These fuel cells are being applied to vehicles recently with the object of reducing environmental pollution and resource depletion, and fuel cells applied to a vehicle are formed into stacks of individual unit cells stacked to generate the considerable potential required to drive the vehicle. In other words, fuel cells applied to vehicles are formed into so-called fuel cell stacks.
Referring to Republic of Korea Registered Patent Gazette No. 10-1610115, a conventional fuel cell stack includes an enclosure (30) having an interior space and a cell that is disposed in the interior space of the enclosure (30) and that generates electrical energy; the cells are formed as a plurality, and the plurality of cells are stacked to form a unit stack module (10).
Additionally, in the enclosure are formed an enclosure inlet and an enclosure outlet (31) for supplying and discharging air required for the electrochemical reaction of the cell.
However, such a conventional fuel cell stack had the problem of foreign matter being introduced into the interior of the enclosure. And the conventional fuel cell stack had problems in that, due to the foreign matter, the fuel cell stack would overheat, the performance and efficiency of the fuel cell stack would fall, and short circuits would occur.
Patent Document—Republic of Korea Registered Patent Gazette No. 10-1610115.

Fuel cell stack and vehicle with a fuel cell stack


This system comprises vertical platter devices (4) including a support tower (43), vertical platters (41, 42) with as many removable rings (5) for winding the film projected in the corresponding theatre, a sprocket (46) for eventual pulling of the film (3), free-turning rollers (47) for guiding the film (3), a tension roller (6) and push buttons (9) to control the operation of the vertical platters (41,42) and the sprocket (46). The system further includes auxiliary devices (7) for cutting and/or splicing the film (3).

35 mm wide films are usually projected in multiplex cinemas with several theatres.
Each one of these theatres has a single film projector projecting the entire film without interruption, the latter being stored in a feature-film device called a non-rewinding horizontal platter system.
The 35 mm film or copy is spiral wound on a horizontal platter such that the beginning of the film is inside the spiral and the end is on the outside thereof. With this configuration on the horizontal feed platter, the film comes out from the centre of the spiral and, with its own motorised feed regulator system, the horizontal feed platter feeds the 35 mm film which is thread onto a second horizontal platter provided with a ring in which all the film is spiral wound until the end, such that when the session is finished the central film-bearing ring is removed and placed again on the horizontal feed platter for a new projection performing the aforementioned steps.
When performing the spooling or winding of the film as it is displayed, the end of the film corresponding to the beginning is always arranged in the central or inner area of the reel; therefore this feature film system is usually called a non-rewinding horizontal platter system.
With this system a different film or title is normally projected in each one of the theatres of the multiplex cinema.
Frequently and especially in the case of those films with high spectator demand it is convenient to project the same film or title in two or three theatres. This operation is currently performed in two different manners described below.
In a first process, called synchronous, a single film is used, simultaneously projecting it in several theatres and using to this end contiguous or adjacent theatres. In order to do this the film is placed on the horizontal feed platter of the projector in said first theatre, threading and projecting this single copy on the projector of said first theatre. When exiting this projector the film is then guided by means of rollers to the projector in the second theatre, passing through the projector responsible for projecting the film in this second theatre.
When exiting this projector, the film is then guided by means of rollers towards the projector in the third theatre, where the entire film is also continuously projected.
Therefore, with this process continuous film projection is performed in the three adjacent theatres, starting the film in the three rooms with a minimum time difference, which may range between 30 and 60 seconds, depending on the distance the film must cover between the adjacent rooms.
This process therefore allows projecting the same film practically simultaneously in three theatres, thereby increasing the number of viewers that may watch it in the same schedule or session; however, it has the drawback that another multiple projection may not start until the previous session has finished because the film is still in use.
This system therefore allows increasing the number of viewers that can watch the film practically simultaneously, but does not allow to offering greater scheduling capacity.
Another process which is different to the previous one but also common, can be performed when the film distribution company provides a greater number of copies of the same title, three, for example.
In this case, the usual process is followed at a logistics level in each theatre, that is, each projector with its own feature film systems. However, in this case a much more profitable and commercial offer can be provided, regarding scheduling, with respect to the previous process, since the projection of each theatre, being independent, may be started with a time difference approximately equal to a third part of the total film duration. This greater scheduling offer allows the viewer to choose between a greater number of starting times and, when arriving at the multiplex cinema, to have a smaller waiting time until the next session begins than in the previous case.
Therefore, the technical problem set forth is to develop a system for continuous film projection of a single film in several multiplex cinema theatres having the advantages of the two previously mentioned systems, that is, that by means of using a single film or copy the entire film may be continuously projected in several theatres, having film sessions or projections in said theatres at different times, starting the session in any one of the theatres when the same film is still being displayed in another theatre.

Vertical platter system for dividing a 35 mm cinematographic film and increasing the number of starting times of the film in several theatres in a multiplex cinema with a single copy description


Disclosed is a loop-back apparatus in wireless communication systems, including: an MAC processing unit configured to transmit a user data and a control frame when a loop-back mode is established; a loop-back unit configured to generate a response frame of a receipt for the user data and the control message transmitted from the MAC processing unit and again feedbacks the generated response frame to the MAC processing unit.

1. Field of the Invention
Exemplary embodiments of the present invention relate to an apparatus and a method for loop-back in wireless communication systems, and more particularly, to an apparatus and a method for loop-back data to be transmitted to a medium access layer between a medium access layer and a physical layer in wireless communication systems.
2. Description of Related Art
Generally, a loop-back scheme for returning original data to a sender without transmitting the data to a receipt by feedbacking the data to a transmitting apparatus without transmitting the data from the transmitting apparatus transmitting the data to a receiving apparatus in a communication system has been prevalently used. The loop-back scheme has been used as various purposes. However, the most important purpose of the loop-back scheme is to verify integrity of a communication path that is being currently used.
For example, in a wired network such as an asynchronous transfer mode (hereinafter, referred to as "ATM") or Ethernet, the loop-back uses a line loop-back method of connecting a cable line that is a channel transmitting data from a physical layer (PHY) to a receiving unit of the sender transmitting data rather than an opponent receipt receiving the data. As another loop-back scheme, there is a scheme of loop-backing the data to be transmitted between the medium access layer (hereinafter, referred to as "MAC") of the sender and the physical layer without performing a handover to the physical layer and allowing the receiving unit of the MAC to receive the data, or the like.
However, unlike the wired network, it is difficult to adopt loop-back technologies of the wired network as they are due to characteristics of the wireless communication systems to be accessed to a shared medium called the wireless channel. In particular, unlike a carrier sensing multiple access/collision detection (hereinafter, referred to as "CSMA/CD" of wired Ethernet) scheme, the wireless access network of Institute of Electrical and Electronics Engineers 802.11 (IEEE 802.11) based wireless access network uses a carrier sensing multiple access/collision avoidance (CSMA/CA) method and thus, it is difficult to adopt a loop-back technology as it is in the existing wired Ethernet.
For example, in the wired Ethernet, detecting a carrier and then, immediately transmitting data when the wired channel is empty and confirming whether the data originally reach the receipt are considered that the data are originally transmitted to a receipt when collision does not occur through collision detection (CD). On the other hand, in the 802.11 based wireless access technology, a sender secures the shared wireless channel and then, transmits data to be transmitted through a process of first transmitting a control frame to the receipt after sensing the carrier and allowing a receipt to transmit a response control frame thereto to a sender.
In addition, in the 802.11 based wireless access technology, unlike the wired Ethernet depending on the collision detection, confirming whether the data originally reach the receipt transmits the control frame having a meaning that the receipt receives the data well to the sender and the sender determines that the data reach the receipt as they are only when the sender receives the control frame as it is.
Therefore, in the 802.11 based wireless access technology, when implementing the loop-back function, like the wired Ethernet, when all the frames transmitted by the sender are loop-backed as they are, two problems may occur as follows. First, the sender transmits the control frames to be transmitted before transmitting data. This waits for the response frame of the receipt to the control frame transmitted by the sender so as to allow the sender to transmit the data when the control frames are simply loopbacked to the sender. However, the sender cannot permanently receive the response frame of the receipt since the control frame transmitted by the sender are loopbacked and thus, are not transmitted to the receipt, thereby failing to secure the wireless channel.
Second, when simply loop-backing the data transmitted by the sender that the receipt is expected to transmit the receive acknowledgement ACK to the sender, the data transmitted by the sender are loop-backed and thus, the sender does not permanently receive the ACK message to the data transmitted by the sender. Therefore, the normal data transmission is considered as being failed.
Accordingly, in the 802.11 based wireless communication systems, since the share wireless channel access method is different from the existing wired network, it is impossible to apply the existing loop-back technology as it is. Therefore, a need exists for a new loop-back method considering unique characteristics of the wireless communication systems.

Apparatus and method for loop-back in wireless communication systems

Electronics and Telecommunications Research Institute


One embodiment provides a method for training a machine-learning model to detect a location of a person's appendix, comprising: receiving, at the machine-learning model, a plurality of images, each image being a slice of a body taken by a CT scan; identifying, for each of the plurality of images, features of the appendix, wherein the identifying comprises analyzing a plurality of slices of each of the plurality of images and classifying each of the plurality of slices, into one of a plurality of classification groups, based upon a feature of the appendix within the slice; segmenting each of the plurality of image slices included in the one of the plurality of classification groups that classifies the slice as containing the appendix, thereby identifying probable locations of the appendix, via utilizing a probability mask for each of the probable locations.

Acute appendicitis is the most common cause of acute-onset abdominal pain which results in emergency abdominal surgery. If caught early enough, uncomplicated acute appendicitis can be diagnosed with high accuracy using computed tomography (CT), thereby allowing for rapid treatment of the appendicitis. However, the location of the appendix within a human may fluctuate considerably, which may make it difficult to correctly setup the patient for the CT scan or to find the appendix on the images resulting from the CT scan(s). Previous studies have concluded that there are six common positions an appendix may be located within a human. Along with determining the position of the appendix, the visualization rate of the appendix in a CT examination is important. A CT examination may provide a professional with an image of a human's appendix, and depending on the appearance of appendix in the CT image, a professional can determine if the appendix comprises acute appendicitis or if the appendix is normal and may exclude a diagnosis of acute appendicitis.

Determination of appendix position using a two stage deep neural network


A circuit arrangement for dividing an input signal A by a signal B, for eple for use in localizing radiation detection, has a dividing analog-to-digital converter receiving an addition signal A+q.times.B as well as the divisor signal B to form the quotient (A+q.times.B)/B from which a digital random value r is subtracted, where r corresponds to q. The ADC can be a Flash ADC and the resulting circuit has good differential linearity and is fast.

A division of signals of the type described above is required for localization of radiation fields utilizing detector systems which can pick up radiation from the field simultaneously, namely, so-called localizing detector systems. By the provision of such detectors which simultaneously pick up radiation from the fields, it is possible to significantly shorten measuring times for localization of points in the radiation field with respect to operations with individual detectors which may be driven in a column-and-row format as is the case, for example, with thyroid gland scans in medicine.
It is known, for example, to provide multiple sources of radiation or radioactive implants with appropriate detectors for effecting a thyroid gland scan utilizing techniques relating to a radionuclide imaging, tomography, emission-computed tomography and the like. An example of a detector system for determining locality by simultaneously picking up radiation at a field from a plurality of detectors is the Anger camera for radiation fields, utilized in medicinal diagnostics.
A particular field of use for location-determining detectors is the field of scientific and technological research utilizing directed or non-directed radiation, for example for the reconstruction of three-dimensional images from two-dimensional sections provided by two-dimensional tomography in nondestructive testing and evaluation of materials and bodies.
The signal processing for all location-determining detector system's involves pulse division.
This can be effected separately with analog dividers and analog-to-digital converters provided at the outputs of the analog dividers or by numerical division following digitization of the dividend and divisor signals. Both processes are, however, relatively slow and expensive since the analog process requires pulse stretchers and the numerical process requires hard-wired calculators or computers.
Another type of signal processing in which the division and digitalizaton can be effected in a single step can be carried out in principle with a dividing analog-to-digital (ADC) whose reference potential is proportional to the signal level of the divisor and is modified to always be proportional to the signal level of the divisor.
When a dividing ADC is used in accordance with the Wilkinson process, excellent differential linearity is obtained. However, the process is relatively slow since the divisor signal may be subjected to a stretcher.
If division is carried out using an ADC operating in accordance with the principles of the successive approximation process, a stretching of the divisor signal is still required. As a consequence, the process is also slow. In addition, the differential linearity .+-.1/2 LSB (least significant bit) is poor. In principle, the fastest ADC is a parallel ADC (Flash) which can generate simultaneously n-bit digital information with 2.sup.n -1 comparators. If such an ADC is operated as a divider, no stretcher is required and as a consequence, the division-digitalization process is extremely fast. However, the differential linearity with .+-.1/2 LSB is unacceptable.
An averaging process utilizing an ADC is described in the prior art (see Cottini et al, A New Method for Analog to Digital Conversion, Nuclear Instruments and Methods, Vol. 24 (1963), pages 241-242) primarily for ADCs utilizing successive approximation principles whereby for multiple channel analyzers, a relatively short pulse-height-independent deadtime with good differential linearity will result.
The relatively short pulse-height-independent deadtime guarantees that a successive approximation process can be effected and the requisite good linearity achieved. For dividing ADCs, however, this process cannot be used.

Divider circuit using analog-digital converter

Kernforschungungsanlage Julich Gesellschaft mit Beschrankter Haftung


There is disclosed an underpinning pile to provide an efficient, simple and sure method in driving and lifting the foundation and at the same time securing the direct transference of preload without further loss of preload from the building into the newly completed driven pile. A pile anchor head (11) is provided that receives a pile (12) and is provided with a lifting means (13). The pile anchor head (11) and lifting means (13) receive the building load and transfers it to the pile (12), which allows practically any kind of material and shape of pile (12) to be used.

Prior art teaches various methods for underpinning to strengthen settling foundation, via primarily two types of underpinning, namely the active and passive underpinning pile. Further, most of the methods are adapted for underpinning a wall foundation rather than a typical large pile cap which carries a concentrated load from the structural concrete frame of the building.
In passive underpinning pile, the new pile is inserted adjacent to the existing settling foundation and then is either bonded or connected to the pile cap or footing by means of a cantilever bracket, ties or enlarged footings. The settling foundation is allowed to settle further until the passive underpinning pile becomes loaded gradually with time. Such method has weakness as continuing settlement can occur over a long period especially if the pile is deep. Such use of passive underpinning piles is common as in U.S. Pat. No. 4,834,582 by Roger Bullivant which uses slanted cast in situ concrete piles and support ties beams. UK pat no:—2,047,303 by Leonard Flowerday has a vertical pile but a concrete cantilever corbel to carry the adjacent footing.
In an active underpinning pile, a certain amount of preloading is applied instantaneously upon the underpinning pile to support the weakened foundation, preventing it from any further settlement. An existing method in the prior art uses a system of complicated prefabricated steel brackets in conjunction with an arrangement of screws, rams or hydraulic jacks reacting against the existing weak foundations. In some cases, very cumbersome apparatus consisting of twin jacks or rams are used to react against the newly installed underpinning pile. A further weakness in some systems lies in the use of many complicated small parts, which may deteriorate and thus be unable to carry a large load if any key mechanism is damaged by wear or rust.
U.S. Pat. No. 5,120,163 by Holdeman has an inverted U-shaped coupler adapted to be temporarily secured to the foundation support to allow the hydraulic jack to react between the screw pile and footing. This method has many small screws and many other interconnecting parts, thus is adapted only to carry a smaller load due to the slant screw piles. This feature is also quite similar to U.S. Pat. No. 5,213,448 by Seider which uses a bracket for uplifting the footings.
US Pat no:—2002/0176749 A1 by Provost has an oversized anchor pile driven at a 15 degree slant at the foundation edge and installation of an anchor jack-plate having a collar and gusset attached thereto, slideable upon the screw anchor shaft. The eccentricity of the floating piers 16 reduces the capacity of the pile and is a source of weakness due to shearing in the jack plate and bending in the pile.
U.S. Pat. No. 3,796,055 by Mahony, uses a method and apparatus for lifting the foundation by gripping the sides of a pipe to drive it vertically against the adjacent foundation, in conjunction with jacks at a number of specified stations to lift the foundation. Portions of the buildings foundation are raised to further include the step of dispersing a body of hardenable cementations material outwardly of and below the lower end of the pipe to an enlarged hardened region of subterranean support resting on top of the pipe. This method is adapted for small load transfer as the enlarged cementations material can shear easily.
U.S. Pat. No. 5,433,556 by Freeman III, uses a pier driving assembly which includes a pier driving bracket which drives the pier pipes into the ground. This method is not suitable for underpinning inside the building due to the massive and deep excavation underneath the existing weakened foundations
UK Pat no:—2,190,693 A by Frank Whittaker, uses an underpinning device for a wall structure comprising a bracket member 35 extending from a rectangular or tabular, hollow box-like member 34, locatable over the top of a previously driven support pile. In addition, an adjustable support means 37, 38 is located on the bracket 35. This system of cantilever demands that the pile is capable of overcoming the bending resistance from the bracket cantilever member and thus is anticipated for use with steel pipes or such that can offer corresponding bending resistance. Deep excavation is required underneath the footing to allow access for the placing of jacks or adjustable support means. Also wider and extensive excavations are required apart from the reduced capacity of the pile due to bending.
UK Pat no:—2,150,612 A by Arthur Joseph Steel, uses a system for underpinning a wall foundation comprising driving a plurality of tabular sleeves 13, by using hydraulic jacks, into which concrete is poured and allowed to harden. This is also similar in principle to UK Pat no:—2,024,283 A by John Patrick Jones, except that the pile has a central aperture running therethrough. Both methods involve waiting time for concrete curing and workability problems due to delays, as well as deep and wide excavations.
UK pat no:—2,255,990 by Roger A Bullivant uses a method of supporting the foundation by removing a short length of two or three courses of brick and supporting the building above the removed portion on a joist 14 with a pile connector 16 resting on a jack 28. The jack is stressed and the pile connector slides through the pipe pile and is fixed to it after stressing. This method uses the jack to react against the existing footing and thus only a certain reaction force is available from the old footing. The eccentricity of the pile connector 16 causes a large shearing and bending on the welds connecting the portion of C-channel to the pipe shaft 12. This method again is adapted for a low load as in a wall foundation.
Pending Malaysian patent no:—PI 20005487 filed by the present applicant discloses an underpinning pile system that works rather similarly to the present invention. However, PI 20005487 employs welding rather extensively which results in a slower process, inconsistent quality and costly operation. Apart from those problems, safety is another concern since welding parts may snap and cause serious hazards to workers. Therefore there arises a need for a design that eliminates or reduces the above problems. The design should be easy to handle, fast, efficient and safer than underpinning pile systems of the prior art.

Pile anchor head for an underpinning pile and method of preloading the same


A computer tomography apparatus for imaging an object includes a computer coupled to a data acquisition system, a carrier that traverses the object through an imaging volume, and a radiation source. In one embodiment, the computer is configured to update scan parameters based upon data received from a first subset of a detector surface. In a second embodiment, the computer is configured to reverse carrier direction and repeat the traversing of the object through the imaging volume with updated scan parameters based upon data received from the first traversing of the object through the imaging volume.

The present invention relates to a computed tomographic imaging device and a method for operating such a device in a continuous or helical mode with automatic adjustment of the device based on analysis of the data being gathered to later construct images. Computed Tomography (also called Computed Axial Tomography, CAT, or CT scanning) has evolved through several major changes, or generations, in its roughly 25 year history. The earliest scanners collimated the x-rays from a tube source into a "pencil beam" and scanned that beam linearly across the object or patient to be imaged and onto a single, synchronously moving detector, or later onto a linear array of detectors. These measurements comprised one view of the object. The tube and detector assembly (usually mounted on a rotating gantry) were then rotated a small angle around the object and another view was acquired. The steps of linear motion and rotation in a plane were repeated many times over at least 180 degrees, usually over a full circle or 360 degrees. Given enough view data in a single plane, any of several known algorithms can be used to reconstruct the planar representation of local x-ray attenuation, that is, a CT image.
A major improvement in CT occurred with adoption of so-called fan beam technology. In this advance, the x-ray beam is collimated into a nearly planar beam, tightly collimated in the axial or z-direction defining the thickness of a slice to be imaged, but spread out over an angle, called the fan angle, to cover the complete width of the object and a generally curved array of detectors on the opposite side of the object. In so-called third-generation CT designs, the detector array is usually curved, is roughly matched in azimuthal extent to the fan of x-rays, and rotates on the gantry to remain opposite the imaged object. In fourth-generation designs, the detector array covers the full arc of view data, generally a full circle, and is fixed so only a varying portion is irradiated by the x-ray fan beam as it rotates. As initially introduced, these devices acquired the full set of azimuthal views for one slice before moving the object (generally on an axially movable table) to a new slice location and acquiring data for a new planar image. For this step-and-shoot operation planar reconstruction methods are substantially correct.
The next major geometry change in CT was development of methods for helical scanning. In this advance, the scanner hardware geometry is largely unchanged--the x-ray tube and the curvilinear detector array rotate in a plane around the imaged object which is substantially perpendicular to its axis. However, now during the rotation the object is moved along the axis (usually on a moving table), so the net path of both tube and detector around the object is a helix. The axial distance covered during one gantry rotation divided by the slice thickness is called the helical pitch. Because the inter-scan delay for advancing the object is eliminated, helical scanning can cover more axial distance in a given time than the earlier step-and-shoot methods. However, because the view data for an image are no longer coplanar, image reconstruction methods must be modified to reduce the potential for artifacts. Helical scanning was introduced to commercial medical CT in the late 1980s and dominated clinical scanning protocols by the mid-1990s.
The latest major change in CT is introduction of two-dimensional or multi-row detector arrays. In this advance, the single arced row of detector cells is replaced by an array which is segmented in both the usual azimuthal direction and the axial direction. A fourth-generation scanner operating with a three-row detector is described by Heuscher et. al. in U.S. Pat. No. 4,965,726. A third-generation scanner with a two-row detector is described by Arenson et. al. in U.S. Pat. No. 5,228,069. In U.S. Pat. No. 5,291,402, Pfoh describes a general approach to multi-slice scanning in which the detector can be arranged to have any number of rows. Since these detectors can cover several slices in the axial dimension, collimation of the x-rays at the tube is opened up to cover substantially the full array; the beam has an axial (or cone) angle in addition to its azimuthal (or fan) angle. Except for the simplest case of a butted two-row detector, that of Arenson et. al. and essentially that of Heuscher et. al., the slice thickness or axial resolution then becomes determined at the detector rather than at the x-ray tube collimator. Reconstruction algorithms now must deal with data gathered from more than one row of detectors, and, of course, they are designed to produce more than one image of the object per system rotation. In addition, since the planes defined by the separate detector rows are not coplanar, further changes must be made to combat artifacts from non-coplanar data. Many special reconstruction algorithms have been developed for such helical, non-coplanar scanning, for example those described by Hu in U.S. Pat. Nos. 5,377,250, 5,400,255, 5,430,783, 5,513,236, and 5,541,970, by Tam in U.S. Pat. Nos. 5,390,112 and 5,504,792, and by Saito in U.S. Pat. No. 5,541,971.
The combination of multi-slice detectors with helical scanning compounds the challenge to dealing with non-coplanarity or incompleteness in the view data, but for small enough cone angles and small enough scan pitches these problems have been solved and this combination appears to be the technology of choice for high-end CT systems.
CT scanners today generally operate with preselected scan protocols. That is, before the start of the scan, the operator selects the volume to be covered (e.g. diameter of field of view and axial coverage) and several machine parameters (e.g. rotation speed, x-ray tube voltage, x-ray tube current, slice thickness, helical pitch, and mathematical parameters of the reconstruction algorithm, such as those which determine view filtering prior to backprojection). When these choices are made, the scan is started and proceeds to completion without change of protocol.
In some cases, large temporal changes occur in the object during the course of the scan. For example, in scans of patient cardiovascular anatomy the motion of the heart and blood or the bolus action of contrast agents injected in the vascular system produce such changes. Because standard CT reconstructions presume consistency of all views used, changes in the object during acquisition of view data will produce blurring and other significant artifacts. Several methods have been developed to deal with such temporal changes, among them those by Yamagishi in U.S. Pat. No. 5,383,231, Brown in U.S. Pat. No. 5,459,769, Toki et. al. in U.S. Pat. No. 5,612,985, Bae et. al. in U.S. Pat. No. 5,687,208, and Lutz in U.S. Pat. No. 5,832,051.
An object which is to be imaged is also typically not cylindrically uniform in space. Methods have been developed to determine spatial variations of the object in advance of a CT scan--for example, from a planar projection image called variously a scoutview or a scanogram--then predetermine and preprogram scan parameter changes which optimally account for this spatial structure. For example, Toth in U.S. Pat. No. 5,379,333 teaches a method for adjusting x-ray flux during gantry rotation around objects with high aspect ratio, such as human shoulders. Fujimoto et. al. in U.S. Pat. No. 5,386,446 teaches a method for predetermining axial regions of the object which would be best scanned with higher or lower image resolution, then preprogramming and controlling the scanner to do so in one scan operation.
In addition, during the course of a continuous or helical scan new regions of the scanned object continually enter, then progressively pass through, an imaging volume--the volume which at all times during the scan is being traversed with x-rays from the source to the detector. The imaging volume is generally a cylinder with center line on the bore of the scanner, with diameter which shadows the useful azimuthal extent of the detector, and with axial length equal to the axial x-ray beam width or that which shadows the useful axial extent of the detector, whichever is smaller. The passage of a given slice region of the scanned object across the imaging volume (i.e., the time when it is affecting the view data being gathered by the detector) may be anywhere from about half the revolution time of the gantry to several revolutions of the gantry. The view data to produce images of this new slice region is gathered over substantially all of this traverse. All of this view data is gathered using scan parameters determined before the slice region enters the imaging volume, in most cases scan parameters chosen before the start of the helical scan. If the slice region contains structures previously unknown, for example, an unlocated lesion in a human patient or a hidden flaw in a manufactured object, the predetermined scan parameters may be adequate to detect the presence of the structure, but sub-optimal for giving detailed information on it. In some cases, the user of the CT scanner may decide to do a re-scan of the object using more optimal scan parameters after images from the first scan have been produced and viewed and the location and general nature of a particular region of the object is appreciated for the first time.
In U.S. Pat. No. 5,796,802, Gordon discloses systems and methods for using a pre-specified subset of CT imaging views, generally widely spaced in projection angle, to test for the presence of target structures in the imaging volume. Only if the test indicates sufficient probability of a target structure are CT images reconstructed, or is a complete scan made if one had not been theretofore. In U.S. Pat. No. 5,818,897 the same inventor discloses a two-dimensional CT detector system with one class of detector cells for imaging and a different class of detector cells for collecting view data to be separately tested to find predetermined target structures, in one embodiment by examination of sinogram data. While Gordon's patents contain methods which test view data to find target structures, in neither invention does he address the challenge of the preceding paragraph, namely determining the presence of target structures as soon as possible after their entry into the imaging volume of a helical scan so the imaging process can continue from that point with changed and optimized scan parameters.

Helical computed tomography with feedback scan control


Provided are an apparatus and method for searching a start position of a broadcast program. According to an embodiment of the present invention, a received broadcast program is recorded in a recording medium while being output as video and audio. If a new broadcast program is started, position information regarding a start part of the new broadcast program is stored in a memory. Thus, a current broadcast program is reproduced from a start part by searching a start position of the current broadcast program recorded in the recording medium with reference to stored position information. A determination on whether the new broadcast program is started is done on the basis of Electronic Program Guide (EPG) information or a change in audio and video signals. Accordingly, it is possible to quickly search and reproduce a start part of a broadcast program which is currently recorded.

1. Field of the Invention
The present invention relates to a method and apparatus for searching a start position of a broadcast program, and more particularly, to an apparatus and method for searching a start position of a broadcast program which is recorded in a recording medium.
2. Description of the Related Art
Digital broadcast receivers, such as a set top box (STB), for receiving digital broadcasts are widely popularized. Recently, a digital broadcast receiver having a Personal Video Recording (PVR) function which is capable of recording broadcast programs in a recording medium such as a hard disc drive (HDD), is developed and popularized.
The digital broadcast receiver, as illustrated in FIG. 1, includes a tuner 10, a signal processor 11, a MPEG decoder 12, a microprocessor 13, an OSD generator 14, a memory 15, a HDR (HDD Recording) system 16, a hard disc (HDD), etc.
The microprocessor 13 controls the tuner 10 to select an arbitrary broadcast channel according to a user's request, and controls the signal processor 11 and the MPEG decoder 12 to output a broadcast program received through the broadcast channel as audio and video.
Also, the microprocessor 13 controls the HDR system 16 to record, in real time, a broadcast program being received in the HDD 17, according to a user's request.
In the HDD 17, as illustrated in FIG. 2, a header area, a File Allocation Table (FAT) area, and a data area are divided and allocated.
When recording broadcast programs in the data area of the HDD 17, the microprocessor 13 creates first, second, and third program information Program#1_Info, Program#2_Info, and Program#3_Info respectively corresponding to first, second, and third broadcast programs Program#1, Program#2, and Program#3 sequentially recorded, and records the first, second, and third program information Program#1_Info, Program#2_Info, and Program#3_Info in the FAT area. The first, second, and third program information Program#1_Info, Program#2_Info, and Program#3_Info include addresses Add# of data sections in which the respective programs are recorded, data sizes, reproduction times, etc.
If a user requests reproduction of an arbitrary broadcast program, for example, the third broadcast program Program#3, the microprocessor 13 reproduces the third broadcast program Program#3 from its recording start position with reference to a start address Add# included in the corresponding third program information Program#3_Info.
However, a digital broadcast receiver having a general PVR function creates the corresponding program information and records it in a FAT area after a data recording operation of recording a broadcast program in a HDD is terminated. Accordingly, when a user requests reproduction of a start part of a broadcast program which is received and recorded in real time, it is difficult to quickly search a recording position corresponding to the start part of the broadcast program.
Also, although a broadcast program which is received and recorded in real time changes to a new broadcast program while a data recording operation is performed, the digital broadcast receiver manages only the recording position of the broadcast program received when the data recording operation has been started, without separately managing a recording position of the new broadcast program. Accordingly, it is difficult to quickly search a recording position corresponding to a start part of a broadcast program which a user currently listens and views.

Apparatus and method for searching start position of broadcasting program


A substrate center-finding method and apparatus, for determining the center of a substrate being passed through a substrate handling chamber of a substrate processing system, includes any number of sensors arranged in any configuration and permits the substrate to pass through any trajectory that triggers the sensors. The locations of the sensors are calibrated by homing in on the sensors using a point, the reference point, near the tip of an arm assembly on a substrate handler. The substrate handler has an encoder for sensing the pivot angles of links in the arm assembly, whereby the coordinates of the reference point can be calculated from the angles and lengths of the links. When the substrate triggers a sensor, the location of the reference point is again calculated, and the coordinates of the trigger point on the edge of the substrate is determined relative to the reference point. A suitable number of trigger points on the edge of a circular substrate will define a circle, so the center of the circle can be calculated, and the location of the substrate can be adjusted to account for any offset from the reference point.

1. Field of the Invention
The present invention generally relates to methods and apparatuses for handling a moving object, such as a substrate, in a processing system. Specifically, the present invention relates to methods and apparatuses for determining the center of a substrate while the substrate is moving through a substrate handling environment of a vacuum processing system.
2. Background of the Related Art
Vacuum processing systems for processing 100 mm, 200 mm, 300 mm or other diameter substrates are generally known. Typically, such vacuum processing systems have a centralized transfer chamber mounted on a monolith platform. The transfer chamber is the center of activity for the movement of substrates being processed in the system. One or more process chambers mount on the transfer chamber at the position of slit valves through which substrates are passed by a substrate handler, or robot, pivotably mounted in the transfer chamber. Access to the transfer chamber from a clean ambient environment is typically through one or more load lock chambers attached at other slit valves. The transfer chamber substrate handler is mounted in the middle of the transfer chamber and can access each of the process chambers and load lock chambers to transfer a substrate therebetween. The load lock chambers may open to a very clean room, referred to as the white area, or to a substrate handling chamber, typically referred to as a mini-environment. The mini-environment transfers substrates in a very clean environment at atmospheric pressure from pods, or cassettes or carriers, seated on pod loaders to the load lock chambers.
The mini-environment has a substrate handler for transferring the substrates. The substrate handler in the mini-environment is typically different from that in the transfer chamber, since it is typically capable of translational and vertical movement as well as rotation and extension; whereas, the substrate handler in the transfer chamber is typically only capable of rotation and extension. Either type of substrate handler has an arm assembly for manipulating the substrates that it transfers. One prevalent type of arm assembly has multiple arms pivotably attached to each other at pivot joints in order to extend and retract a blade, or end effector, which supports the substrate. The position of the arms is typically determined from an encoder that detects the angle of the pivot joints. A controller, such as a microcomputer, receives signals from the encoder and calculates the position of the blade.
A typical processing system includes a substrate center-finding system locates the center of the substrate in order to adjust the location of the substrate, so the substrate is centered on each of the structures which support the substrate in the system to avoid damage to the substrate and to ensure proper processing of the substrate. The center-finding system typically includes a set of emitter/sensor pairs, such as infrared beam emitters and sensors, for detecting the edge of the substrate. The center-finding system is typically disposed in a part of the processing system through which the substrate is passed, such as the transfer chamber or the mini-environment, so that the sensors can detect the edge of the substrate at several locations as the substrate passes through the beams. These substrate center-finding systems that determine the location of the center of a substrate while the substrate is moving are called on-the-fly center-finding systems.
On-the-fly center-finding systems are quite often used to make corrections for substrate misalignment. They typically consist of banks of through-beam or reflective sensors, such as an infrared emitter/sensor pair, arranged in the chamber through which the substrates pass. A typical arrangement for the sensors may have three to nine sensors arranged in one to three sensor banks. A substrate handler passes a substrate through the sensor beams. When the substrate interferes with, or cuts, a beam, the associated sensor is triggered and sends a signal to the controller indicating the trigger. When the controller receives a trigger signal, the controller records the encoder position. Thus, as the substrate is passed through the bank of sensors, information on the substrate position is obtained by recording the substrate handler encoder position every time a sensor triggers by and computing the substrate center from the positions. The accuracy and repeatability of existing methods, however, is dependent on the accuracy of placement and alignment of the sensors, the need to move the robot along straight line or circular paths and a known, constant speed of the substrate. For example, some types of on-the-fly center-finding systems require the substrate to be moved in a straight line through the sensor beams, use two sensors that must be arranged in a line perpendicular to the straight line of the substrate movement, assume the radius of the substrate, and do not work for substrates having substrate flats. Another type of center-finding system requires the substrate to be moved in a circular arc and uses three sensors that must be arranged in a line perpendicular to a tangent of the arc. Some centering-finding systems also require the use of a calibration substrate to calibrate the system, so the performance of the system is also dependent on the characteristics of the calibration substrate.
FIG. 1a shows an example of a substrate center-finding system such as the one described in U.S. Pat. No. 4,819,167, which is assigned in common with the present application and is incorporated herein by reference. In this center-finding system, a substrate 14, on a blade 16, is passed through an array of sensors 10-12 in a straight-line path in the direction of arrow A to determine the x-y coordinates of points on the edge of the substrate 14, with the x-axis being in the direction of the substrate path. The sensors 10-12 are required to be positioned in a straight line that is perpendicular to the path (arrow A) of the substrate 14 and blade 16. A further requirement is that the blade 16 has a hole 18, which must be aligned with the middle sensor 11. The location of the blade 16 is calibrated by sending a calibration substrate through the center-finding system to find the center of the blade 16. Other prior art center-finding systems may also require the substrate to be moved in a straight line as described in this example, or may require that the substrate be moved in a circular line.
The center-finding system shown in FIG. 1a requires seven coordinate points, one for the blade position, and six for the substrate position. As the substrate 14 and blade 16 pass through the sensors 10-12, the blade 16 triggers the middle sensor 11 when the hole 18 is detected at point X.sub.1, thus providing the blade position. For some substrate center-finding systems of this type, the hole 18 may be very difficult to align to the sensor 11 and, thus, hard to detect. As the substrate 14 continues to move, the substrate 14 triggers the middle sensor 11 at the leading edge of the substrate 14, point X.sub.3. The substrate 14 triggers the outer sensors 10, 12 to provide the next leading edge positions at points X.sub.2 and X.sub.4. The substrate 14 next triggers the outer sensors 10, 12 to provide the trailing edge positions at points X.sub.5 and X.sub.7. Finally, the substrate 14 triggers the middle sensor 11 to provide the last trailing edge position at point X.sub.6.
This center-finding system determines the x-coordinates for the points X.sub.2 -X.sub.7 by recording the distance the blade 16 has traveled at each of these points from point X.sub.1. The point X.sub.1, the blade position, is defined as the origin of the coordinate system, and the x-coordinate for the six substrate points are calculated with reference to the blade position. The average x-coordinate for each pair of substrate points for each sensor is calculated. If the substrate is completely circular, then all three averages should be about the same and should correspond to the x-coordinate for the center of the substrate 14. However, most substrates have a substrate flat 20 or notch in order to indicate the alignment of the substrate. In FIG. 1a, the substrate flat 20 is shown to be in the path of the middle sensor 11, so the substrate 14 will trigger the middle sensor 11 to provide the trailing edge point X.sub.6 at the substrate flat 20. The substrate points X.sub.3, X6 for this sensor 11 will provide an average x-coordinate that is substantially different from the averages for the other pairs of substrate points, thus identifying the fact that the middle sensor 11 was triggered by the substrate flat 20. The data points X.sub.3 and X.sub.6 for the sensor 11 can be discarded, and the other four data points X.sub.2, X.sub.4, X.sub.5 and X.sub.7 can be defined as valid, or useable, data points. The x-coordinate of the substrate center is determined from the average of the x-coordinates for the valid data points.
The y-coordinates of the sensors are predetermined from a measurement of the distance between the sensors and define the y-coordinates for each of the data points. A calculation for approximating the y-coordinate of the center of the substrate 14, is based on the x-y coordinates of the valid substrate points and the x-coordinate determined above. The correction for the center of the substrate is determined by comparing the calculated actual x-y coordinates of the substrate center with a calibrated x-y center coordinate corresponding to the blade center. Once the x-y coordinates for the center of the substrate 14 are determined, the controller for the substrate handler adjusts the movement of the substrate 14 to center the substrate 14 appropriately in a chamber where it is to be processed.
A problem with this center-finding system is that it has several inflexible requirements. One of the requirements of this system is that the substrate 14 must move in a straight line in the direction of arrow A. If the substrate 14 does not move in a straight line, then the data points X.sub.1 -X.sub.7 will not line up according to the dashed lines shown in FIG. 1a, and none of the calculations will be correct. Another requirement is that the sensors 10-12 must be in a straight line. If any of the sensors 10-12 is not in a straight line with the other two, then the calculation for the average x-coordinate, as measured from point X.sub.1, of the pair of data points for that sensor will not be valid. Yet another requirement is that the line of the sensors 10-12 must be perpendicular to the line of the substrate movement (arrow A). If the line of the sensors 10-12 is not perpendicular to the line of the substrate movement, then none of the average x-coordinates for each of the pairs of data points for all of the sensors 10-12 will be the same. Another requirement is that there must be at least three sensors 10-12. If there is less than three sensors, then it will not be possible to discard one pair of data points to account for the substrate flat 20, since the calculations cannot proceed with just one pair of data points. Still another requirement of this center-finding system is that, if the system starts processing a different size substrate, then the distance between the sensors 10-12 may have to be changed. If the processing system starts processing larger substrates, then the sensors may have to be spaced further apart, so the substrate flat cannot cross more than one sensor. On the other hand, if the processing system starts processing smaller substrates, then the sensors may have to be spaced closer together, so the sensors will not miss the substrate. Such repositioning of the sensors 10-12 requires very careful measurements of the new locations of the sensors. Each of these requirements adds to either the complexity of the overall system or its cost or both.
FIG. 1b shows an example of another substrate center-finding system that has certain inflexible requirements such as those discussed above. The substrate 40 is supported on a substrate blade 42 of a substrate handler disposed in a chamber, such as a transfer chamber. The blade 42 is operated by two struts 44 attached to a motion actuator of the substrate handler. The substrate handler can move the substrate 40 back and forth inside the transfer chamber in a circular path, represented by arrow F, in order to move the substrate 40 between the various process chambers and load lock chambers attached to the transfer chamber. A bank 48 of sensor units 50-52, for sensing the edges of the substrate 40, is mounted in the transfer chamber in the path of the substrate 40. The substrate 40 triggers the sensor units 50-52 on its leading and trailing edges as it passes through the sensor beams emitted from the sensor units 50-52. In addition to requiring that the substrate 40 be moved in a circular path, center-finding systems of this type have required that the sensor bank 48 include at least three sensor units 50-52, that the sensor units 50-52 be placed in a straight line, and that the straight line of the sensor units 50-52 be radial to the rotational center of the substrate handler. Thus, similar to the center-finding system shown in FIG. 1a, the type of center-finding system shown in FIG. 1b has inflexible requirements that add to either the complexity of the overall system or its cost or both.
Additionally, a problem with some prior art center-finding systems includes the need to have a calibrating substrate for an operator to calibrate the system. The calibrating substrate is known to have a very precise geometry, and the operator places it in the processing system with its centering and alignment known, so that the accuracy of the center-finding system may be determined.
A need, therefore, exists for a substrate center-finding system and method that permits a very flexible operation without strict requirements on the shape of the path of the substrate, the size of the substrate, the positioning of the sensors, the number of sensors, or a calibration substrate.

On the fly center-finding during substrate handling in a processing system