JP2009130382A - Video signal multiplex transmitter, and imaging apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To visually recognize the change amount of data for compressing external video signals to be transmitted on a transmission side video monitor and to recognize it in real time. <P>SOLUTION: In a digital triax system for bidirectionally transmitting serial digital signals for every 25 lines by a triax cable between a control part and an adapter part connected to an imaging part, external video signals are compressed for every 25 horizontal scanning lines, and dot-like graph signals for which the horizontal direction is a data amount and the vertical direction is a time base are generated from the compressed data amount of the external video signals and a transmission data amount to be transmitted, superimposed on imaging part video signal output or the transmission side monitor video signals of the external video signals, and displayed on the video monitor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an improvement of a transmission method in a video signal multiplex transmission apparatus used for an imaging apparatus such as a television camera apparatus.

  Conventionally, in a television camera system, a main line video signal, a return video signal, an audio signal, a control serial data signal, between an adapter unit connected to an imaging unit (camera head) and a control unit (Camera Control Unit: CCU), In addition, a method of performing time-division bidirectional transmission for power transmission / reception with a transmission line of one triple coaxial cable is called a digital triax system. As a simple method, a normal coaxial cable may be used for the transmission line.

  Main video signals include NTSC with 485 effective scanning lines as SDTV and PAL with 575 effective scanning lines, 720 effective scanning lines and 1080 effective scanning lines as HDTV, 2160 effective scanning lines as SHDTV, and effective scanning as UHDTV. There are 4320 lines, and NTSC will be described as a representative.

  The NTSC 10-bit 4: 2: 2 broadcast video digital signal output from the imaging unit has a data amount of 270 Mbps, and the sent-back video signal has a data amount of about 50 Mbps even after data compression (hereinafter video compression). In the case of time-division bidirectional transmission, the video signal is time-compressed and converted to a signal of about 360 Mbps and transmitted from the adapter unit connected to the imaging unit to the control unit intermittently in a short time. Then, during a period free by time compression, the video signal of the send-back time-compressed to 360 Mbps is intermittently transmitted in a short time from the control unit to the adapter unit connected to the imaging unit. The process is switched by an input / output switch at a rate of several times per second to realize time-division bidirectional transmission (Patent Document 1).

When using a digital triax system in a TV station studio or a broadcast site, external video images from other cameras on the air or video for the announcer's script are input to the control unit, and the external video signals are sent to the triax cable. The image is transmitted to the adapter unit and output to the viewfinder of the camera or the script projection device, which is called send-back image transmission. Also, an operation called trunk video for transmitting an external video signal on the adapter unit side is performed instead of transmitting the return video. In order to transmit an external video signal, H.264 of inter-frame compression is used. Video compression such as H.264, JPEG2000 for intra-frame prediction, JPEG-LS, and differential encoding is performed.
Japanese Patent Laid-Open No. 7-203399

  In general, when compressing an external video signal to be transmitted with a low delay, H.264 is generally used every 25 horizontal scanning lines. Since it is compressed by a H.264 encoder and transmitted in a time-sharing manner, A buffer memory for accumulating output data encoded in H.264 is required. Here H. The amount of data output from the H.264 encoder temporarily increases when the picture or video signal of the external video signal is switched. Therefore, it is necessary to determine the capacity of the buffer memory after estimating the temporary increase amount of the encoded data. H. As a method for estimating the output data amount of the H.264 encoder, there is a method of superimposing a signal obtained by quantifying the output data amount on an external video signal and monitoring the output signal of the imaging unit with a monitor. However, in this method, since it is necessary to read the change amount information of the output data numerically, it is difficult to grasp the change amount of the data that changes in real time.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems and to realize an observation method capable of instantaneously grasping in real time change amount information of video signal data sent back and compressed by a low-delay encoder.

  In order to achieve the above object, the present invention transmits a digital signal including a digitized video signal, audio signal, and control signal through one transmission line, and compresses and transmits at least a part of the video signal. In the video signal multiplex transmission apparatus, a means for generating a dot-shaped transmission side graph signal with the horizontal direction of the video signal as the data amount and the vertical direction as the time axis from the video signal compressed data amount and the transmission data amount and the transmission side Means for superimposing the graph signal on the transmission side output video signal, and the horizontal direction of the video signal from the received data amount (with null removed) from the video signal received on the reception side, and the vertical direction as the time axis. At least one of: a means for generating a dot-shaped receiving-side graph signal; and a means for superimposing the graph signal on the receiving-side output video signal. An image signal multiplexing transmission apparatus.

  Further, in the above, the means for generating the graph signal includes the video signal compression data amount and transmission data amount for each scanning line number for performing the video signal compression, or the video signal compression for each scanning line number for bidirectional transmission. The video signal multiplex transmission device is a means for generating at least one of a data amount and a transmission data amount, or a reception data amount for each number of scanning lines performing bidirectional transmission.

  Further, in the above, the graph further includes means for selecting an imaging unit video signal output to the video signal on which the graph is superimposed, and means for generating a graph of the compressed data amount and transmission data amount of one or more external video signals. A video signal characterized by at least one of: means for selecting a predetermined external video signal to the video signal on which is superimposed; and means for generating a graph of the compressed data amount and the transmission data amount of the predetermined external video signal Multiplex transmission device.

  Further, means for generating a dot-shaped reception side graph signal with the horizontal direction of the video signal as the data amount and the vertical direction as the time axis from the reception data amount obtained by deleting null from the video signal received at the reception side, and the graph signal Is a video signal multiplex transmission apparatus comprising: means for superimposing a signal on a reception side output video signal; and means for varying a video compression parameter on a transmission side on a reception side.

  Moreover, it is an imaging device provided with said video signal multiplex transmission apparatus.

  That is, the present invention is a device for displaying the compressed video data amount, the transmitted data amount, or the received data amount for each predetermined number of scanning lines.

  As described above, according to the present invention, the amount of change in the amount of compressed data or the amount of transmitted data or the amount of received data of a video signal compressed every 25 horizontal scanning lines by a low-delay encoder is used. By monitoring with a dot-shaped graph with the direction as the time axis, the amount of compressed data that changes with time can be monitored in real time, and changes in data can be grasped instantly compared to reading with numerical data. Can do.

  FIG. 3 is a block diagram showing the entire triax system of one embodiment of the present invention, and FIG. 3 is a block diagram showing an example of the configuration of an external video signal data amount display unit of one embodiment of the present invention. A description will be given with reference to FIG. 1 of FIG. 1 and FIG. 2 of a schematic diagram showing a screen of a compression data amount and transmission data amount graph of the external video signal compression unit of one embodiment of the present invention.

  In the following description of the embodiment, RET external video input of VBS and PROMPT external video input of serial digital video signal (SDI) are used as analog video signals to be sent back, and H.264 is used as video compression. H.264 will be described.

  In the block diagram of FIG. 1 showing the entire triax system, the VTS RET external video input input to the control unit 48 is converted to a 10-bit parallel signal by the A / D 6 and sent to the video compression unit 4 for bidirectional transmission. Compression is performed for each number of scanning lines. The PROMPT external video input to the control unit 48 is waveform-equalized by a cable equalizer (EQ) 1 and then a clock synchronized with data and data by a clock data recovery unit (CLOCK AND DATA RECOVERY: CDR) 2. Extracted. Then, using the clock and data, the serial-parallel converter 3 converts it into a 10-bit parallel signal, which is sent to the video compressor 4 and compressed.

  In compressed external video data, RET data and PROMPT data are alternately read, and one bit for determination is added to the beginning of the data (for example, 0 for the MSB of RET data, 1 for the MSB of PROMPT data) After the transmission data amount is adjusted by the buffer memory 7, it is time-division multiplexed by the multiplexing unit 17 together with the control data output from the CPU 18, and output from the control unit 48 through the switch 19 and the plug 40. . Here, the switch 19 is for switching the input and output by a timing unit 11 of the control unit 48 in a predetermined time unit (about 1.6 milliseconds in this embodiment). The signal flow when the switch is on the output side is as described above. However, when the switch is on the input side, the uncompressed video signal of the imaging unit from which blanking has been removed is input from the adapter unit 47 side, and the buffer memory 35 After the blanking time is adjusted, the parallel-serial conversion unit 36 outputs the serial digital video signal from the control unit 48.

  On the other hand, in the adapter unit 47, the data sent from the control unit 48 via the triax cable 23 and the plug 39 passes through the switch 38, and is separated into compressed video data and control data by the separation unit 49. Here, the switch 24 is time-division bi-directional between the control unit 48 and the adapter unit 47 by switching the input and output by the timing generation unit 30 of the adapter unit 47 and synchronizing the switch timing with the switch 19 of the control unit 48. Realizes transmission.

  The compressed video data is sent to the video decompression unit 31 after the data transfer speed is adjusted in the buffer memory 30, and the decompressed video signal is converted into an analog composite video signal by the VBS encoder 29 and output from the adapter unit 47. The

  The incident light from the imaging unit 46 passes through the lens 41 and is split into three colors of red (R), green (G), and blue (B) by the color separation optical system (Prism) 42, respectively. It is converted into a digital video signal by the image sensor 43. The image sensor 43 may be a CMOS image sensor, a CCD image sensor, a drive circuit, CDS, AGC, and A / D.

  The digital video signal from the image sensor 43 is subjected to signal processing such as black balance, white balance, and γ correction in the video signal processing unit 44. The output signal from the video signal processing unit 44 is time-compressed by the rate conversion unit 32 and the buffer memory 33 of the adapter unit 47, and the audio signal, CPU data, utility data (cable correction circuit setting data, etc.) and the multiplexing unit 34. The signals are multiplexed and transmitted to the control unit 48 through the switch 24, the plug 39, and the triax cable 37.

  A graph of the external video compression amount and the transmission data amount is created from the external video compression data read alternately and the external video data to be transmitted, and is superimposed on the transmission side monitor video. In FIG. 1 of the block diagram showing the configuration example of the external video signal compression unit of one embodiment of the present invention, the video signal on which the graph is superimposed is switched from the imaging unit video signal output, the RET external video signal, or the PROMPT external video by the switch 21. Selected. Basically, the transmission side monitor video is the external video of RET and PROMPT in FIG. 2 which is a schematic diagram showing the screen of the compression data amount and transmission data amount of the external video signal compression unit of one embodiment of the present invention. The compressed data and transmission data are superposed on the imaging unit video signal output and monitored. A RET external video signal or a PROMPT external video may be selected by the switch 21 as the transmission side monitor video, and a graph of the external video compressed data and the transmission data on the left or right half of FIG. 2 may be displayed.

  First, a method for creating a graph of the amount of compressed external video data will be described. The compressed data of the external video compression is divided into RET compressed data and PROMPT compressed data by the external video compressed data determination circuit 24 and input to the RET compressed data integrating circuit 13 and the PROMPT compressed data integrating circuit 14. Thereafter, the respective compressed data amounts are accumulated by 25H by the compression scanning line counter 15 that manages the timing of 25 horizontal scanning lines (hereinafter referred to as 25H). Thereafter, each integrated data is written in a memory (Dual Port Random Access Memory: DPRAM) 16. Next, by controlling the timing of reading data from the DPRAM 16 by the screen display positioning counter 17, the vertical coordinates for displaying the data on the screen are determined. Further, the data value read from the DPRAM 16 by the comparator 18 is compared with the counter value to determine the horizontal coordinate when the data is displayed on the screen. Since the graph is displayed for 225 horizontal scanning lines, the DPRAM 16 is reset by the display scanning line counter 19 that manages the display range. Thereafter, the output signal from the comparator 18 is used to switch the graph display level of the video signal and the compressed data with the switch 20, and the external video compressed data amount graph is superimposed on the video signal (external video compressed data displayed on the video signal). The graph of the amount is the amount of compressed data every 25H, and it is a graph on a dot of one pixel pixel).

  Next, a transmission image data graph creation circuit will be described. The transmission video data determination circuit 25 divides the RET transmission data and the PROMPT transmission data, and inputs them to the RET transmission data integration circuit 26 and the PROMPT transmission data integration circuit 27, and performs the processing described in the method of creating the external video compression data amount graph. Is input to the DPRAM 16 and superimposed on the video signal.

A graph of the amount of compressed external video data and the amount of external video transmission data displayed as a video signal is shown in FIG. There are four display graphs, and from the left, RET external video compression data amount, RET external video transmission data amount, PROMPT external video compression data amount, and PROMPT external video transmission data amount are shown. The number of display pixels in the horizontal and vertical directions of the graph is as shown in FIG. The horizontal direction of the graph is the compressed data amount of each line (the maximum value of the H.264 encoded data amount is 21504 bytes, the maximum value of the transmission data amount is 1600 bytes), and the vertical direction indicates the time axis (the time axis is from top to bottom) direction). The vertical display area of the graph is 225 lines, and one line indicates the amount of compressed data for 25H. Therefore, the amount of compressed data that can be displayed on the screen at one time is vertical display area (225 lines) / (number of NTSC scan lines (525 lines) / 25 lines)
= 10.7 (frame)
Thus, 10.7 frames of compressed data can be displayed at a time.

  Next, as a display example of the graph, a case where the external video compressed data amount exceeds the maximum value of the compressed transmission data amount will be described. When the external video compression data volume exceeds the maximum transmission data volume (1600 bytes), the compressed transmission data for 25H cannot be transmitted at a time. Therefore, the compressed transmission data for 25H is transmitted in several times. In such a case, the graph of the RET and PROMPT transmission data becomes a straight line like the transmission at the maximum transmission amount in FIG. 2, and the compressed transmission data continues to be transmitted at the maximum transmission data amount until all the external video compressed data can be transmitted.

  In the above description, the serial digital video signal sent back is described as an example, but the parallel digital video signal processing after A / D is the same for the analog video signal.

  The above is the H.264 format for compressing NTSC with 243 field effective scanning lines every 25H. 1 is a block diagram showing an example of the configuration of the external video signal compression unit of one embodiment of the present invention. FIG. 1 shows the number of scanning line counters and the display of the compression scanning line counter 15 and the graph screen display positioning counter 17. By changing the number of scanning line counters of the scanning line counter 19, it can be applied to PAL, HDTV, JPEG-LS, and differential encoding. FIG. 3 of the block diagram showing the whole triax system of one embodiment of the present invention is also applicable to PAL and HDTV if the video compression unit 4, the A / D converter 6, the VBS encoder 29, and the video expansion unit 31 are changed. Can also be applied to JPEG-LS and differential encoding.

  In particular, if the video compression parameters are changed in the imaging unit menu or the control unit menu while visually checking the video compression data amount and transmission data amount graph superimposed on the monitor image on the transmission side, the transmission band becomes narrower. It is easy to optimize video compression parameters according to the application at the relay site that transmits long distances.

  If the cable equalizer 1, the clock data recovery unit 2, the serial-parallel conversion unit 3, the video compression unit 4, and the data amount display unit 5 are moved to the adapter unit 47, the adapter unit side instead of transmitting the return video. The present invention can also be applied to optimization of video compression parameters in an adapter called “trunk video” that transmits external video signals.

  Further, the imaging unit video signal is also compressed and transmitted by the adapter unit 47, the imaging unit video signal received by the control unit 48 is input to the transmission video data discrimination 25 by the data amount display unit 5, and the imaging unit video signal data from which null has been deleted is deleted. A dot-shaped receiving side graph signal with the horizontal direction of the video signal as the data amount and the vertical direction as the time axis is generated from the amount, superimposed on the monitor video output by the switch 20, and received by the control unit 48 at the imaging unit video signal. The video compression parameter on the transmission side of the adapter unit 47 may be changed from the control unit 48 side while visually checking the data amount on the video monitor.

  By the way, when the screen changes drastically, it is preferable that the data graph is stored in the memory for about 1 second, and the data graph also displays the current component and the afterimage component of about 1 second.

  In addition, the present invention is not limited to broadcasting stations and relay sites, and it is easy to change the parameters of video compression with low delay. Specifically, H.C. When low-latency video compression is introduced for surveillance purposes due to improvements in H.264, JPEG2000, JPEG-LS, differential encoding, etc., the video compression data amount and transmission data amount graphs can be viewed visually on the transmission side video monitor. However, if the video compression parameters are made variable, it is easy to optimize the low-latency video compression parameters in accordance with the illumination conditions for monitoring purposes, subject, S / N deterioration, contrast reduction, and transmission band shortage. Therefore, the time for local adjustment is shortened.

The block diagram which shows the structural example of the external video signal compression part of one Example of this invention The schematic diagram which showed the screen of the graph of the compression data amount and transmission data amount of the external video signal compression part of one Example of this invention The block diagram which shows the whole triax system of one Example of this invention

Explanation of symbols

13: RET compressed data integrating circuit, 14: PROMPT compressed data integrating circuit, 15: compression scanning line counter, 16: DPRAM, 17: screen display positioning counter, 18: comparator, 19: display scanning line counter,
22: D / A converter (D / A), 24: compressed video data discrimination circuit, 25: transmission video data discrimination circuit, 26: RET transmission data integration circuit, 27: PROMPT transmission data integration circuit,
1: cable equalizer (EQ), 2: clock data recovery unit (CDR), 3: serial-parallel conversion unit, 4: video compression unit, 5: data amount display unit, 6: A / D converter (A / D) 7, 30, 33: buffer memory, 8, 34: multiplexing unit, 9, 45: CPU, 10, 20, 21: switch,
29: VBS encoder, 31: Video expansion unit, 32: Rate conversion unit, 36: Parallel-serial converter, 37: Triax cable, 39, 40: Plug, 41: Lens unit, 42: Color separation optical system, 43: imaging device, 45: video signal processing unit, 46: imaging unit, 47: adapter unit, 48: control unit, 49: separation unit,

Claims (4)

In a video signal multiplex transmission device for bidirectionally transmitting a digital signal including a digitized video signal, audio signal, and control signal through one transmission line, and compressing and transmitting at least a part of the video signal, the video signal A means for generating a transmission-side graph signal in the form of a dot with the horizontal direction of the video signal as the data amount and the vertical direction as the time axis from the compressed data amount and the transmission data amount and the transmission-side graph signal are superimposed on the transmission-side output video signal. And generating a dot-shaped receiving side graph signal with the horizontal direction of the video signal as the data amount and the vertical direction as the time axis from the received data amount (with null removed) from the received video signal on the receiving side And a means for superimposing the graph signal on the output video signal on the receiving side. 2. The video signal multiplex transmission apparatus according to claim 1, wherein the means for generating the graph signal includes the video signal compressed data amount and transmission data amount for each number of scanning lines for performing the video signal compression, or scanning lines for performing bidirectional transmission. A video signal multiplex transmission apparatus that generates at least one of the video signal compressed data amount and the transmission data amount for each number, or the received data amount for each number of scanning lines performing bidirectional transmission. 3. The video signal multiplex transmission apparatus according to claim 1, wherein means for selecting an imaging unit video signal output to a video signal on which the graph is superimposed, and a graph of compressed data amount and transmission data amount of one or more external video signals. Or means for selecting a predetermined external video signal on the video signal on which the graph is superimposed, and means for generating a graph of the compressed data amount and the transmission data amount of the predetermined external video signal. A video signal multiplex transmission device characterized by having at least one of: An image pickup apparatus comprising the video signal multiplex transmission apparatus according to claim 1.