CN1697484A - Method and apparatus for simultaneous multiple visual field imagers - Google Patents

Abstract

PURPOSE: A method for generating two fields of view images from a sensor pixel array and an image device having the first and second fields of view are provided to generate a wide field of view and high resolution using a single camera without requiring a powered platform and to generate multiple fields of view using a single sensor array. CONSTITUTION: A method for generating two fields of view images from a sensor array provides an array of sensing pixels. The array sequentially generates a plurality of digital data streams respectively corresponding to blocks of the sensing pixels to generate an array digital data stream. All of sensing pixels are simultaneously sampled in an arbitrary block. The first and second digital video streams are generated from the array digital data stream. The first and second digital video streams respectively include the first and second fields of view of the array. Each pixel of the first digital video stream corresponds to at least one filtered and sub-sampled combination of sensing pixel samples.

Description

Be used for the method and apparatus of various visual angles imager simultaneously

The application requires to be incorporated by reference in this text and to examine in the priority of the U.S. Provisional Patent Application sequence number 60/470147 of submission on 05 13rd, 2003.

Technical field

The present invention relates to the design of high-resolution imaging device, relate in particular to a kind of imager of exporting wide region window and high-resolution window simultaneously.

Background technology

Usually expectation provides wide visual angle and the high-resolution scene by camera record.This realizes by two kinds of video cameras in the prior art: in conjunction with the wide-angle imaging machine and the high-resolution camera of electric platforms use.The shortcoming of these methods is by second video camera and the extra cost that causes such as the ancillary hardware of rotation platform.

Some prior art inventions relate to imaging system.United States Patent (USP) 5926218 teachings that propose by Smith a kind ofly have a video camera that is used for producing first Low Resolution Sensor of viewfmder image and is used for producing second high-resolution image sensors of high-definition picture.The United States Patent (USP) 5532737 that is proposed by Braun discloses a kind of camera chain, wherein places the identical image that a plurality of video cameras are used for receiving via mirror system different visual angles.By the United States Patent (USP) 5065024 that McCollough proposes a kind of infrared imaging system has been described.This system can change the visual angle.Use many detectors that the visual angle of variation is provided convertibly.United States Patent (USP) 5023719 teachings that propose by Zwirn a kind of method that a plurality of realtime graphics are provided from thermal camera.

Summary of the invention

Main purpose of the present invention provide a kind of effectively and the imager structure that can make fully.

Another object of the present invention provides and does not a kind ofly need electric platforms to produce wide visual angle and high-resolution method by using single camera.

A further object of the present invention provides a kind of by using the single-sensor array to produce the method at a plurality of visual angles.

Another purpose of the present invention provides a kind of by filtering with the son sampling and by using a plurality of analog to digital converters to produce the method at a plurality of visual angles according to the single-sensor array.

Another purpose of the present invention provides a kind of method that does not need the processor that separates.

Another purpose of the present invention provides and a kind ofly can produce a plurality of visual angles and do not need the imager of the electric platforms of optical system.

According to purpose of the present invention, realized a kind of method that produces two visual angle images according to sensor pixel array.Described method comprises provides the sensing pel array.Produce the number of arrays digital data streams by producing a plurality of digital data streams successively, each digital data stream is corresponding to the piece of the described sensing pixel in the described array.Whole described sensing pixel in any described is sampled simultaneously.Produce first and second digital video frequency flows according to described number of arrays digital data streams.Described first and second digital video frequency flows comprise first and second visual angles of described array respectively.Each pixel of described first digital video frequency flow is corresponding to that filter and the combination more than the described sensing pixel sampling son sampling.

And according to aspects of the present invention, realize a kind of imaging device with first and second visual angles.Described device comprises sensing pel array and a plurality of analog to digital converter.Comprise that also each digital data stream is corresponding to the piece of the described sensing pixel in the described array by producing the device that a plurality of digital data streams produce the number of arrays digital data streams successively.Whole described sensing pixel in any described is sampled simultaneously by described analog to digital converter.First visual angle is read piece and is produced first digital video frequency flow according to described number of arrays digital data streams.Described first digital video frequency flow comprises first visual angle of described array.Each pixel of described first digital video frequency flow is corresponding to that filter and the combination more than the described sensing pixel sampling son sampling.Second visual angle is read piece and is produced second digital video frequency flow according to described number of arrays digital data streams.Described second digital video frequency flow comprises second visual angle of described array.

Description of drawings

In the accompanying drawing of the data part that forms this explanation, show following accompanying drawing:

Fig. 1 illustrates a kind of optimum embodiment of the present invention that the block diagram of various visual angles imager is shown;

Fig. 2 illustrates the preferred embodiment that wide visual angle and the processing of narrow visual angle are shown;

Fig. 3 illustrates the preferred embodiment of the system of the fritter that illustrating is used for walking abreast reads staggered pixel with the block diagram form;

Fig. 4 illustrates the preferred embodiment of the system that the fritter that is used for the parallel pixel that reads noninterlace or tile is shown with the block diagram form;

Fig. 5 illustrates with the flow chart form preferred embodiment that is used to filter the system that staggered pixel reads is shown; With

Fig. 6 illustrates the preferred embodiment that the system that the pixel that is used to filter tiling reads is shown with the flow chart form.

Embodiment

The preferred embodiments of the present invention disclose a kind of formation method and device of novelty.Imager according to the single-sensor array and the not electronic optics of needs or platform just can provide narrow and wide visual angle.It will be clear to one skilled in the art that under the situation that does not deviate from scope of the present invention and can use and expand the present invention.

With reference now to Fig. 1 to 6,, comes graphic extension below and various visual angles imager of the present invention is discussed.Especially referring to Fig. 1, show the block diagram of the preferred embodiment of various visual angles imager of the present invention.This device comprises that a plurality of analog to digital converters 116 and two windows in pixel sensor array 100, the ADC piece 102 read piece 104 and 114.Pixel sensor array 100 is well-known elements that comprise material (such as semi-conducting material) in the prior art, is used for converting incident light to the signal of telecommunication.Pixel sensor array 100 comprises a large amount of single pixels, thus the image in the incident light of can decoding.Typically, each pixel produces the aanalogvoltage that is directly proportional with the incident light intensity.By using parallel A/D converter (ADC) piece 102 to convert analog imaging device pixel value to digital value.Parallel ADC piece 102 has a large amount of parallel sub-pieces 106 of analog to digital converter (ADC), and the sub-piece of each analog to digital converter is used for changing the subclass or the piece of the pixel of pixel sensor array 100.Figure 1 illustrates eight ADC pieces 116.The use of the parallel ACD piece 116 in the ADC piece 102 can be read the high-resolution imaging device fast, for example under the situation of 2K * 2K pixel.And, use many more parallel ACD pieces 116, can carry out more parallel processing, each ADC piece 116 can be with lower clock frequency operation.Clock frequency is low more, and the precision that obtains from each ADC piece 116 is just high more.

Analog to digital converter is sampled (being eight pixels in this case) to each pixel in the piece simultaneously, so that produce digital stream for this piece.The window that is sent to two or more groups from the digital stream of ADC piece 102 reads piece 104 and 120 subsequently.102 pairs of block of pixels of ADC piece are sampled successively, thereby according to the periodic basis of frame entire pixel array 100 are carried out digital translation.On each frame of sampling, the accumulated sequence of the piece digital stream that is produced (as the also line output of ADC piece 102) forms the array digital stream of whole array.

Fig. 1 shows two windows and reads piece, and first window reads piece 104 and second window reads piece 114.Each " window " is corresponding to the visual angle of pixel sensor array.First window reads piece 104 controls first visual angle, and second window reads piece 114 controls second visual angle.Each window reads piece 104 and 114 can comprise a plurality of sub-pieces, for example filter/sub-sampler 108, subwindow selector 110, adaptive multiplexer 112 and the device 122 of retiming.Yet window reads piece 104 and 114 needn't comprise these all pieces.In the example depicted in fig. 1, first window reads piece 104 and shows all sub-pieces: filter/sub-sampler 106, subwindow selector 108, adaptive multiplexer 110 and the device 112 of retiming.The output 118 and 120 that window reads piece 104 and 114 is expression is positioned at the sampling of the pixel value of specifying subwindow with raster scan order sequential flow.

Window reads circuit 104 and 114 and controls from the window of imager output.Usually people expect that imager do not export all pixel values.For example, should read and handle with 126 megahertzes (MHz) for the high-resolution imaging device of every frame with 30 frames/output second 2K * 2K pixel.This computing capability needs expensive hardware.And the video of this resolution and most of existing monitor, video tape recorder and processing unit are incompatible, and the VGA resolution of most of existing apparatus is 648 * 480.110 controls of subwindow selector will be output to the subwindow of the pixel sensor array 100 of first digital video frequency flow 118.The window's position gauge wire 124 and 126 is determined selecteed window.The purpose that window reads piece 104 and 114 is the selection zone that allows with the resolution output imager scope of expectation, and this selection zone may be greater than the resolution of expectation.

Reading piece 104 with reference to first window comes explanation window to read the operation of piece.At first read parallel block digital stream from ADC 116 by filter/sub-sampler 108.This piece comprises filtering circuit, is used for pixel value (may walk abreast) is carried out the digital space filtration and subsequently it carried out the son sampling.The purpose of filtering is the spatial confusion in the minimizing image, and this spatial confusion may be caused by the son sampling.Filter/sub-sampler 108 output sampling on one or more parallel channels 111.Filter/sub-sampler 108 plays the purposes of similar video scalar sheet (video scalar chip), still for the reason of processing speed, in the practice of standard, must use parallel inlet flow rather than sequential flow to realize filter/sub-sampler.And, importantly, realize filter/sub-sampler 108 by use streamline filtration stage in some cases, rather than it is only used only stage.Can not be installed in if the imager circuit is too big in the single chip and the imager circuit must be split two chips,, then expect such multistage design if perhaps the expectation imager uses existing filtrating chip.

The output of filter/sub-sampler 108 is sent to subwindow selector 110, and this subwindow selector selects to be included in those sampling in the subwindow of expectation.Handle output from subwindow selector 110 by adaptive multiplexer 112 subsequently, this adaptive multiplexer will enter single sequential flow from the sampling interleave of the selection of parallel flow, and sampling in this single sequential flow occurs with raster order.Subwindow selector 110 allows by using the window's position gauge wire 124 outside subwindows of specifying.This specification can be provided by operator or auto-programming, and can change each frame.By with frame by frame mover window, obtain digital panoramic/elevation angle (pan/tilt) mechanism system.The device piece 122 of retiming will change regularly form into from the digital pixel circulation of adaptive multiplexer 112 output, and regularly form is compatible with the video input such as the standard set-up of digital quantizer or video recorder for this.If utilized subwindow selector 110, then only need the device 122 of retiming, because the position about the subwindow of pixel sensor array is depended in the timing of the output of subwindow selector 110.

With reference now to Fig. 2,, shows the embodiment more specifically of above-mentioned design.High-resolution digital panorama/elevation angle imager has for example pixel sensor array 200 and two cis of 2560 * 1920 pixels, that is, and and wide visual angle (WFOV) reader 218 and narrow visual angle (NVOF) reader 240.These cis 218 and 240 or digital video frequency flow correspond respectively to WFOV piece 204 and NFOV piece 214.

WFOV video output 218 is the video flowings at whole imager visual angle, but with low resolution of sampling, especially 640 * 480 sampling, perhaps approximate per 4 pixels sampling is once.The processing of sampling fraction 2560 * 1920 sampling of this quantity is cheap on calculating, if WFOV is sampled with the ceiling rate of 1 sampling for each pixel, then produces 2560 * 1920 sampling.In order to produce this output, the WFOV window reads piece 204 and comprises filter/sub-sampler 206 and adaptive multiplexer 208.The subwindow selector and the device of retiming are optional, because the WFOV output 218 entire image scope of covering sensor array 200 often.NFOV reader 240 is the subwindow of typical case's 640 * 480 sampling of imager preferably, and this subwindow obtains with original largest sample rate, for example samples for 1 of each pixel in the array 200.Therefore, the NFOV window reads piece 214 and simply is made up of subwindow selector 226, adaptive multiplexer 228 and the device 230 of retiming.Keep original pixels resolution, thereby do not need filter/sub-sampler.

In this case, use eight parallel ADC 216 to convert analog pixel to digital value.If ADC moves with 20MHz, this means can be to read whole 2560 * 1920 pel arrays less than the time of 33 millisecond of one frame.Spatial model is greatly depended in the design of filter/sub-sampler, reads pixel value on the imager according to this spatial model ADC.Two kinds of basic reader design have been shown in Fig. 3 and 4.

Especially with reference to figure 3, ADC 316 is arranged and is used for to fritter 320 digitlizations, in this case, measures 4 * 2 pixels, the discrete pixels in each ADC parallel processing piece 320, thus read staggered pixel by different ADC.Such design is called alternating expression ADC design.With reference to figure 4, each ADC 416 is responsible for one group of noninterlace pixel 410, thus each ADC 416 image tiling demonstration (image tile) effectively.Such design is called flush system ADC design.Each ADC samples to the part of delegation or the part of row, 1 * m sampling as shown in the figure.

For alternating expression ADC and flush system ADC design, filter/sub-sampler is all used one group of parallel filtering circuit.For alternating expression ADC shown in Figure 3 design, each ADC 316 is connected to the pixel 318 in piece or the adjacent filter 320, also reads and store arbitrary value when reading previous adjacent block.With reference now to Fig. 5,, symbolically shows the design of staggered 4 * 2 readers that filter Fig. 3.Piece 500 comprises 4 * 2 arrays of pixel 502,504,506,508,510,512,514 and 516.Used 3 * 3 separable filters, the sub-sampler of this filter comprises six filtering circuits.Filter comprises filter A 530, B 532, C 534, D 536, E 538 and F 540.Filter A-D carries out 3 taps (3-tap) horizontal filtering, and filter E and F carry out the filtration of 3 tap vertical.Each filtering circuit can comprise that to filter taps weighting is doubly taken advantage of, sues for peace, rounded, the circuit of amplitude limit and convergent-divergent.The output 539 and 541 of filter E 538 and F 540 is the output of filter/sub-sampler piece.This design comes executive level and vertical son sampling according to the factor 2.Clearly,, or expect different sampling fractions, then must change this connection if use more heterogeneous neighbour's filter.Show surrounding pixel 542,544,546,520,522,524 and 526, and filter module 558 and 562.Note, use Postponement module 550,552,556,560 and 564 to merge the surrounding pixel value.

With reference now to Fig. 6,, symbolically shows flush system ADC filter/sub-sampler design.Figure 4 illustrates the flush system design.Refer again to Fig. 6, show 601-608, have filtering circuit 611-618 and sub-sampler 621-628 for each tiling.This design is forward, handles two edges that tiling shows that adjoin although pay particular attention to.

As mentioned above, in some cases, can use the streamline filtration stage to realize filter/sub-sampler piece, rather than only use the single stage to realize it.As mentioned above, when the circuit of carrying out filtration can not be installed on the imager chip too greatly, this situation may appear.The sort of situation can appear when expectation uses a large amount of vertical contiguous filtering circuits to come filtering image.Because each the additional vertical row that is included in the filter comprises wire delay, so the vertical range of the filter of allocated circuit quantity must realize this filtration.Therefore, the multistage filter design is used in expectation, and this design is operated in multistage filter/sub-sampler.For example, suppose that desired operation has the filter of k tap on each direction.For the sum of (k-1) w memory element, be that the full resolution image of w needs k-1 delay line to width with this filter application.According to this filter, can be similar to it by the filter that at first has a m+1 tap with the full images resolution applications.Here suppose that k and n are odd number, suppose that m is an even number.Such design adds up to the individual memory element of mw+ (w/2) with needs.Especially, can select to satisfy the n of equation n+n-1+m=k.In this case, the sum that is used for the memory element of delay line subsequently should be (k/4+3m/4+1/4) w, and this sum depends on the occurrence of k, and m is omissible basically.For example, if k=11 and m=2 and n=5, then for delay line, this will need only 4.5w, rather than 10w memory element.

Another point is noted that the multistage realization of filter/sub-sampler is that adaptive multiplexer can be the part in a stage in the multistage.When the clock frequency of the circuit in a stage that is used to realize last stages is enough fast and can handle the sampling rate of the stream in time-multiplexed stream of wherein sampling, this point is of great use.For example, consider such problem, be about to 11 tap filter application and be w * h and carry out the imager that son is sampled with the factor 4 to frame sign.According to desired filter, this problem is broken down into two stages.Phase I is adopted 3 tap filters, and usage factor 2 is carried out the son sampling.Second stage adopts 9 tap filters, and carries out the son sampling by another factor 2.Can come the processing sequence data with ratio (w/2) * (h/2) * f if be used for the circuit of second stage, wherein f is the frame frequency of imager, then can only use single filter to realize second stage.Therefore, adaptive multiplexer can be placed on the output of phase I and sentence the structure sequential flow.

Refer again to Fig. 2, show the NFOV window and read piece 214.In this piece, subwindow selector 226 takes out parallel data stream from A/D piece 202, and selects to be included in the pixel in the subwindow of expectation.Adaptive multiplexer 228 is exported the pixel of those selections with raster order subsequently, and the device 230 of retiming retimes to those signals, so that consistent with the beginning to the frame time of NFOV output line 240 outputs.Desired subwindow can use NFOV the window's position gauge wire 238 outside appointments by the operator or by auto-programming, and can change for every frame.By frame ground mover window one by one, people obtain digital panoramic/elevation angle mechanism.

An exemplary application of the sort of system is an imaging system, and this imaging system monitors the WFOV output image, so that detection and tracking are moved and specify the NFOV window subsequently, thereby the NFOV window is positioned at the position or the precalculated position of mobile object.NFOV can be sent to monitor subsequently and check, can further handle by additional auto-mechanism in order to the people.So additional mechanism that can be special purpose is " indeformable (unwarping) " circuit.Common practice in the safety camera is to use a kind of maximization by the video camera angle metric imaging arrangement of imaging in " flake " for example.Unfortunately, these imaging arrangements cause the extremely image of distortion usually.Although the people is difficult to the image of these distortions of decipher, still can operate those images for automated evaluation procedure.For example, if automatics detects the motion in the image of distortion, and arrange the NFOV window from the image of distortion, to read suitable subwindow, then can use subsequent treatment to make this distortion " indeformable ", thereby produce undistorted high-resolution window interested mobile object imaging.

Can realize above-mentioned imager design by using many different physical form.The first, analog imaging device piece 200 can be made up of any sensing technology that can convert digital value to.The second, the internal structure of Parallel ADC piece 202 can change.The 3rd, can realize that window reads piece on the chip identical or on the chip that separates, and the different assemblies that window reads in the piece can be arranged in identical chip or different chips with imager piece 200.And, carry out filter/sub-sampler 206, subwindow selector 226 and adaptive multiplexer 208 and needn't separate existence, and may be incorporated in the integrated design with 228 circuit.

Summarize advantage of the present invention now.Provide a kind of effectively and the imager structure that can make fully.Realize a kind of use single camera and do not needed electric platforms to produce wide visual angle and high-resolution method.The described method that produces various visual angles is used the single-sensor array.Described method according to single-sensor array generation various visual angles is to sample by filtering with son, and by using a plurality of analog to digital converters to realize.Described method does not need the processor that separates.Realized a kind ofly can producing various visual angles and not needing the imager of electric platforms.

As shown in preferred embodiment, for prior art, the method and apparatus of novelty of the present invention provides a kind of alternative that effectively also can make.

Although illustrate and described the present invention especially, one skilled in the art will appreciate that under the situation that does not break away from the spirit and scope of the present invention and can make various variations in form and details with reference to the preferred embodiments of the present invention.

Claims (33)

1. one kind produces the method for two visual angle images according to sensor pixel array, and described method comprises:

The array of sensing pixel is provided;

Produce the number of arrays digital data streams by producing a plurality of digital data streams successively, each digital data stream is corresponding to the piece of the described sensing pixel in the described array, and the whole described sensing pixel in wherein any described is sampled simultaneously; With

Produce first and second digital video frequency flows according to described number of arrays digital data streams, wherein said first and second digital video frequency flows comprise first and second visual angles of described array respectively, and each pixel of wherein said first digital video frequency flow is corresponding to that filter and the combination more than the described sensing pixel sampling son sampling.

2. method according to claim 1, wherein said first visual angle comprises whole described array.

3. method according to claim 2, wherein each described sensing block of pixels comprises n * m array, and among wherein said n and the m each is greater than one.

4. method according to claim 2, wherein said filtration step comprise the many tap horizontal filter and the filtration of many tap vertical of described digital data stream.

5. method according to claim 2, wherein said filtration comprise to filter taps that weighting is doubly taken advantage of, sues for peace, rounded, amplitude limit or convergent-divergent.

6. method according to claim 2, wherein said son sampling step are to carry out on the column direction of described array or line direction.

7. method according to claim 2, wherein each described sensing block of pixels comprises 1 * m array, and among the wherein said m each is greater than one.

8. method according to claim 2, wherein said second visual angle comprises the part of described whole array.

9. method according to claim 8, each pixel of wherein said second digital video frequency flow is corresponding to single described sensing pixel sampling.

10. method according to claim 8, wherein about described whole array, the position at described second visual angle is movably.

11. method according to claim 10, wherein about described whole array, the described position at described second visual angle is movably for every frame.

12. method according to claim 8 also comprises step: described second digital video frequency flow retimed is the head end of frame of video.

13. one kind produces the method for two visual angle images according to sensor pixel array, described method comprises:

The sensing pel array is provided;

Produce the number of arrays digital data streams by producing a plurality of digital data streams successively, each digital data stream is corresponding to the piece of the described sensing pixel in the described array, and the whole described sensing pixel in wherein any described is sampled simultaneously; With

Produce first and second digital video frequency flows according to described number of arrays digital data streams, wherein said first and second digital video frequency flows comprise first and second visual angles of described array respectively, each pixel of wherein said first digital video frequency flow is corresponding to that filter and the combination more than the described sensing pixel sampling son sampling, wherein said first visual angle comprises whole described array, wherein said second visual angle comprises the part of described whole array, and the position at wherein said second visual angle is movably about described whole array.

14. method according to claim 13, wherein each described sensing block of pixels comprises n * m array, and among wherein said n and the m each is greater than one.

15. method according to claim 14, wherein said filtration step comprise the many tap horizontal filter and the filtration of many tap vertical of described digital data stream.

16. method according to claim 14, wherein said filtration comprise to filter taps that weighting is doubly taken advantage of, sues for peace, rounded, amplitude limit or convergent-divergent.

17. method according to claim 14, wherein said son sampling step are to carry out on the column direction of described array or line direction.

18. method according to claim 13, wherein each described sensing block of pixels comprises 1 * m array, and among the wherein said m each is greater than one.

19. method according to claim 13, each pixel at wherein said second visual angle is corresponding to single described sensing pixel sampling.

20. method according to claim 13, wherein about described whole array, the described position at described second visual angle is movably for every frame.

21. method according to claim 13 also comprises step: described second digital video frequency flow retimed is the head end of frame of video.

22. the imager with first and second visual angles, described imager comprises:

The sensing pel array;

A plurality of analog to digital converters;

By producing the device that a plurality of digital data streams produce the number of arrays digital data streams successively, each digital data stream is corresponding to the piece of the described sensing pixel in the described array, and the whole described sensing pixel in wherein any described is sampled simultaneously by described analog to digital converter;

Piece is read at first visual angle that produces first digital video frequency flow according to described number of arrays digital data streams, wherein said first digital video frequency flow comprises first visual angle of described array, and each pixel of wherein said first digital video frequency flow is corresponding to that filter and the combination more than the described sensing pixel sampling son sampling; And

Piece is read at second visual angle that produces second digital video frequency flow according to described number of arrays digital data streams, and wherein said second digital video frequency flow comprises second visual angle of described whole array.

23. imager according to claim 22, wherein said first visual angle comprises whole described array.

24. imager according to claim 23, wherein each described sensing block of pixels comprises n * m array, and among wherein said n and the m each is greater than one.

25. imager according to claim 24, wherein said filtration comprise the many tap horizontal filter and the filtration of many tap vertical of described digital data stream.

26. imager according to claim 24, wherein said filtration comprise to filter taps that weighting is doubly taken advantage of, sues for peace, rounded, amplitude limit or convergent-divergent.

27. imager according to claim 24, wherein said son sampling are to carry out on the column direction of described array or line direction.

28. imager according to claim 22, wherein each described sensing block of pixels comprises 1 * m array, and among the wherein said m each is greater than one.

29. imager according to claim 22, wherein said second visual angle comprises the part of described whole array.

30. imager according to claim 29, each pixel of wherein said second digital video frequency flow is corresponding to single described sensing pixel sampling.

31. imager according to claim 29, the position at wherein said second visual angle is movably about described whole array.

32. imager according to claim 31, wherein about described whole array, the described position at described second visual angle is movably for every frame.

33. imager according to claim 29, wherein said second visual angle read piece and described second digital video frequency flow is retimed are the head end of frame of video.

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