JP6853060B2 - Video signal transmission device - Google Patents

Description

The present invention relates to a video signal transmission device, and is applicable to a video signal transmission device that transmits an indicator signal superimposed on the video signal.

In terrestrial digital broadcasting systems and the like, images taken by a camera are transmitted by a transmission device.

When transmitting a video signal from an HDTV (High Definition Television) camera to a camera control device (CCU) with an optical cable or triax (triple coaxial) cable, the CCU side is used to perform color tone correction and gamma correction of the camera while watching the video. As a guide for alignment, a 1-bit indicator signal may be added to the video signal, and the CCU may add the indicator signal to the luminance signal or color difference signal of the video signal and superimpose it on the video signal.

At this time, in order not to affect the original camera image signal as much as possible, the indicator signal is generally inserted into the least significant bit of the color difference signal.

As an example, as in Patent Document 1 (Japanese Unexamined Patent Publication No. 2011-223381), as an indicator signal transmission method with a triax cable, down-conversion is performed to the lower 1 bit of an SD-SDI (Standard Definition --Serial Digital Interface) signal. There is a method of multiplexing the indicator signal and also using it as a parity bit.

Japanese Unexamined Patent Publication No. 2011-223381

However, the method of Patent Document 1 has a problem that the indicator signal may be replaced with a parity bit in order to prevent the occurrence of the SD-SDI prohibition code, and the indicator signal may have missing dots depending on the pattern of the compressed video signal. .. Another problem is that it cannot be applied when the compressed video format is other than SD-SDI.

An object of the present invention is to provide a video signal transmission device capable of transmitting an indicator signal superimposed on a camera video signal without missing dots.

Other challenges and novel features will become apparent from the description and accompanying drawings herein.

A brief description of a typical example of the present invention is as follows.

That is, the video signal transmission device takes out the indicator signal before image compression by the camera adapter, divides the indicator signal for one field into a plurality of slices, packetizes each divided slice, and forms a plurality of fields of the video signal. It is transmitted to the camera control device by dividing it into transfer periods, and the indicator signals of a plurality of slices are combined into one field by the field memory in the camera control device and superimposed on the video signal after image expansion.

According to the video signal transmission device, the indicator signal can be transmitted without missing dots.

It is a figure which shows the structural example of the video signal transmission apparatus which concerns on this invention. It is a figure which shows an example of the screen division method of the indicator signal which concerns on this invention. It is a figure which shows an example of the TS packet arrangement of the indicator signal which concerns on this invention. It is a figure which shows an example of the transfer of a compressed image data and an indicator signal.

Hereinafter, embodiments will be described with reference to the drawings. However, in the following description, the same components may be designated by the same reference numerals and repeated description may be omitted. The drawings may be represented schematically as compared with actual embodiments in order to clarify the description, but they are merely examples and do not limit the interpretation of the present invention.

FIG. 1 is a diagram showing a configuration example of a video signal transmission device according to the present invention.

The video signal transmission device according to the present invention is a digital triax system for bidirectional transmission of serial digital signals between a television camera and a camera control device via a triax (triple coaxial) cable. This will be described as an example. Although the triax cable 11 is taken as an example, any other line (for example, an optical cable or the like) may be used.

The video signal transmission device according to the present invention includes an HDTV (High Definition Television) camera 1, a camera adapter CA, a triax cable 11, and a camera control device CCU. The camera adapter CA and the camera control device CCU can be installed at a distance from each other.

The camera adapter CA includes a serial-parallel conversion unit (S / P) 2, a Y / C separation unit 3, an image compression circuit 4, a screen division unit 7, and a plurality of TS (transport stream) packet generation units. It includes 5, 6 and 8, an OFDM (Orthogonal Frequency Division Multiplexing) modulation circuit 9, and a transmission / reception changeover switch 10.

The camera control device CCU includes a transmission / reception changeover switch 12, an OFDM demodulation circuit 13, an image expansion unit 14, a screen composition unit 15, a field memory 16, an indicator multiplexing unit 17, a character multiplexing unit 18, and a plurality of parallels. -Serial conversion units (P / S) 19 and 20 are provided.

The video signal transmission device of the present invention is configured as follows.

The Y / C separation unit 3 is provided as an extraction means for extracting an indicator signal for one field, which is multiplexed with the video signal of the HDTV camera 1 by one bit, before image compression. Then, the indicator signal for one field taken out is divided into a plurality of slices. A screen dividing unit 7 is provided as a dividing means for dividing the indicator signal for one field into a plurality of slices. The indicator signal divided as the plurality of slices is divided into transfer periods of a plurality of fields of the compressed image data and transmitted to the camera control device CCU. A TS packet generation unit 8 is provided as this transmission means. The camera control device CCU synthesizes a plurality of transmitted sliced indicator signals into one field by a field memory 16 provided in the camera control device CCU. A screen synthesizing unit 15 is provided as this synthesizing means. The indicator signal synthesized in the one field is superimposed on the least significant bit of the luminance signal (Y) or the color difference signal (C) of the video signal after image expansion. An indicator multiplexing unit 17 is provided as this superimposing means.

That is, the video transmission system including the video signal transmission device takes out the indicator signal before image compression by the camera adapter CA, divides the indicator signal for one field into a plurality of slices, and then converts it into a TS (transport stream) packet. Then, the compressed image data is transmitted to the camera control device CCU over a plurality of frame periods, the indicator signals of a plurality of slices are recombined into one field by the field memory 16 in the camera control device CCU, and the image after image expansion is performed. It is superimposed on the lowest bit of the brightness signal (Y) or the color difference signal (C) of the signal.

Hereinafter, an example of the operation of the video signal transmission device according to the present invention will be described in more detail with reference to FIGS. 1 to 4.

With reference to FIG. 1, the camera image signal and the indicator signal are multiplexed by the HDTV camera 1 and sent to the camera adapter CA as an HD-SDI (High Definition-serial digital interface) signal. The serial-parallel conversion unit 2 in the first stage of the camera adapter CA returns the data to parallel data, and the Y / C separation unit 3 separates the luminance signal (Y) and the color difference signal (C) and sends them to the image compression circuit 4. On the other hand, the indicator signal multiplexed with the color difference signal (C) is sent to the screen dividing unit 7.

The image compression circuit 4 uses, for example, MPEG2-TS, H.A., for the input video (image) signal (luminance signal (Y) and color difference signal (C)). Image compression is performed by a compression method such as 264, and the compression result (compressed image data) is sent to the TS packet generation unit 6.

The screen dividing unit 7 divides the extracted indicator signal for one field into a plurality of slices. FIG. 2 shows the processing contents of the screen dividing unit 7. In this example, the effective size of the HDTV1 field is 1920 pixels horizontally and 540 lines vertically, but in order to reduce the transmission amount, the horizontal is thinned out in half to 960 pixels. Next, the vertical direction is divided into 12 blocks (1S-12S) and divided into blocks of 46 lines per slice. The divided one-slice indicator signal is sent to the TS (transport stream) packet generation unit 8 of FIG. 1 and converted into a TS packet as shown in FIG. The TS packet for one slice is transmitted to the camera control device CCU side over a transfer period (1 / 59.94 seconds) for one field of the compressed image data. At this time, the transmission bit rate of the indicator signal for one slice is 960 × 46 × 59.94 ≈2.65 Mbps. FIG. 4 shows the transfer relationship between the compressed image data and the sliced indicator signal. When the transfer of the image data (1F) of the first field of the compressed image data is started at the first time t1, the indicator signal th is synchronized with the transfer of the image data (1F) of the first field. The first slice (1S) is transferred. At the second time t2, when the image data (2F) in the second field of the compressed image data is transferred, the second slice (2S) of the indicator signal is synchronized with the transfer of the image data (2F) in the second field. Is transferred. Similarly, at the third time t3, when the image data (3F) in the third field of the compressed image data is transferred, the third indicator signal is synchronized with the transfer of the image data (3F) in the third field. Slice (3S) is transferred. After that, the transfer of the image data (4F) in the fourth field, the image data (11F) in the eleventh field, and the slice (11S) in the eleventh field from the fourth slice (4S) is sequentially sent. Then, at the 12th time t12, when the image data (12F) in the 12th field of the compressed image data is transferred, the 12th slice of the indicator signal is synchronized with the transfer of the image data (12F) in the 12th field. (12S) is transferred. In this way, the camera control unit CCU, 12 and transfer of the compressed image data of the field content, the transfer of the indicator signal for one field (12 slices) is performed. For example, in the case of a method of transferring compressed image data for 60 fields per second, indicator signals for 5 fields are transferred per second.

Next, the operation of the TS (transport stream) packet generation unit 8 of FIG. 1 will be described. The TS packet generation unit 8 converts an indicator signal for one slice into a TS packet suitable for transmission. FIG. 3 shows the data arrangement of the TS packet. The data array has 8 bits per word, and includes a 4-word header part (TS Header) and a 184-word indicator signal part (INSGP). The first word of the header part is 47h (h indicates a hexadecimal number), and the second word is 34h. The 3rd and 4th words indicate the block number (BN). As shown in the first slice (1S) portion of FIG. 2, one slice (960 × 46) is composed of 30 (0-29) TS packets (8 × 184). Since there are 12 slices in one field of the indicator signal, 30 × 12 = 360 identification numbers indicating which position the TS packet corresponds to in one field are required. A block number (BN) is provided to indicate this identification number. A number from 0 to 359 is assigned to the block number (BN) using two words.

The TS packet generators 5 and 6 of FIG. 1 generate the same TS packet for the compressed image and audio / CPU data, and the OFDM signal is generated by the OFDM (Orthogonal Frequency Division Multiplexing) modulation circuit 9. Is converted to. The transmission / reception changeover switch 10 alternately switches between transmission and reception at a fixed time to perform time-division bidirectional transmission, and the camera adapter CA receives a return signal. Next, it is sent to the camera control device CCU via the triax cable 11, and enters the OFDM demodulation circuit 13 via the transmission / reception changeover switch 12.

The TS packetized indicator signal is written in the field memory 16 and mapped by the screen synthesis unit 15 based on the block number (BN) information of the header unit. As a result, the indicator signals for one field are combined in the field memory 16.

On the other hand, the compressed video is decoded into an HDTV video signal by the image stretching unit 14, and the indicator multiplexing unit 17 reads the indicator signal from the field memory 16 in synchronization with the video signal by the frame synchronization code of the video signal to read the video. The indicator signal is multiplexed with the video signal by adding it to the lowest 1 bit of the luminance signal (for example, Y) or the color difference signal (for example, Pb, Pr) of the signal.

The multiplexed video signal of the indicator signal is multiplexed with character information such as a menu by the character multiplexing unit 18, converted into an HD-SDI signal by the parallel-serial conversion unit 19, and output from the camera control device CCU for monitoring. .. On the other hand, as for the on-air video signal, the video signal from the image stretching unit 14 is directly converted into an HD-SDI signal by the parallel-serial conversion unit 20 and output from the camera control device CCU.

According to the embodiment, the indicator signal superimposed on the camera image signal can be efficiently transmitted as a TS packet without missing dots. Further, since the indicator signal is divided into a plurality of slices and then transmitted in a plurality of field periods, it can be applied even when the compressed video format is other than SD-SDI, for example, MPEG2-TS, and the indicator alone. In addition, the transmission rate can be changed freely.

Although the invention made by the present inventor has been specifically described above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways.

For example, the effective size of the HDTV1 field is 1920 pixels horizontally and 540 lines vertically, but 1920 pixels horizontally and 1080 lines vertically may be used. Further, although the indicator signal for one field taken out is divided into 12 slices, it may be divided into 24 slices or 10 slices.

1: HDTV camera, 2: Serial-parallel conversion unit, 3: Y / C separation unit, 4: Image compression circuit, 5, 6, 8: TS packet generation unit, 7: Screen division unit, 9: OFDM modulation circuit, 10, 12: Transmission / reception changeover switch, 11: Triax cable, 13: OFDM demodulation circuit, 14: Image expansion circuit, 15: Screen synthesizer, 16: Field memory, 17: Indicator multiplex, 18: Character multiplex, 19 , 20: Parallel-serial converter

Claims (5)

The indicator signal is taken out by the camera adapter before image compression, the indicator signal for one field is divided into a plurality of slices, each divided slice is packetized, and the camera control device is divided into the transfer periods of the multiple fields of the video signal. A video signal transmission device characterized by transmitting to, synthesizing indicator signals of a plurality of slices into one field in a field memory in a camera control device, and superimposing the indicator signals on the video signal after image expansion. In a digital triax system that compresses a video signal from an HDTV camera to a camera control device and performs time-division bidirectional transmission.
An extraction means for extracting an indicator signal for one field, which is multiplexed by one bit with the video signal of the HDTV camera, before image compression, and
A dividing means for dividing the extracted indicator signal into a plurality of slices, and
A transmission means for transmitting the indicator signals of the plurality of divided slices to the camera control device over a plurality of field periods.
In the camera control device, a synthesis means for synthesizing a plurality of transmitted sliced indicator signals into one field in a field memory, and
A means for superimposing the synthesized indicator signal on the video signal after image expansion, and
A video signal transmission device characterized by being equipped with. In claim 2,
A video signal transmission device characterized in that the synthesized indicator signal is superimposed on the least significant bit of a luminance signal (Y) or a color difference signal (C). In claim 2,
The dividing means divides the extracted indicator signal into 12 slices.
A video signal transmission device characterized in that the 12 slices are sequentially transmitted to the camera control device over a transfer period of 12 fields of compressed image data. In claim 2,
The transmission means converts one slice into a packet including a header part and an indicator part, and converts it into a packet.
The header portion is a video signal transmission device including an identification number corresponding to a position in one field of the packet.

Images