JPH06291777A - Video signal transmitter - Google Patents

Abstract

(57) [Summary] [Purpose] To transmit high-quality video over an ATM network. [Structure] The characteristic extraction unit 55 extracts characteristic portions such as eyes and nose from the A / D converted video signal. Then, the priority designation section should be set to tighten the disposal conditions of the cell including the information of these sections.
Write down the conditions at 56.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal transmission device used in a packet communication network in which data may be discarded during transmission.

[0002]

2. Description of the Related Art A portrait of a person may be transmitted as in a videophone by using an ATM (Asynchronous Transfer Mode) network. Since video telephone video signals, such as NTSC signals, have an enormous amount of information, methods such as frequency interleaving, time-axis compression multiplexing, fixed or variable sampling are used at the analog stage to improve transmission efficiency, and intra-frame at the digital stage. Data compression is performed using data compression techniques such as predictive coding, interframe predictive coding, and motion compensation interframe predictive coding.

FIG. 1 is a schematic block diagram showing the structure of a conventional video transmission apparatus. The analog signal of the video imaged by the TV camera 1 is input to the A / D conversion unit 21 of the transmission unit 20 of the video signal transmission device 2, converted into a digital signal here, and then input to the compression encoding unit 22, The above-mentioned digital data compression is performed. The compressed data is input to the ATM cell generation / transmission unit 23, divided into cells (transmission units), and transmitted to the ATM network 3. Some cells are discarded due to traffic in the middle of the ATM network 3. On the other hand, in the reception unit 24 of the video signal transmission device 2, the transmitted cell is decompressed to the original compressed data by the ATM cell reception decompression unit 25, then decompressed by the decompression decoding unit 26, and then the D / A conversion unit 27. Is converted into an analog signal and displayed on the monitor 4.

[0004]

Therefore, in the ATM network, some cells may be discarded due to the traffic. In the case of a voice signal, since the redundancy is large, the deterioration of the transmission quality due to the discard is hardly a problem. Although the portion corresponding to the discard cell is interpolated, if the number of video signals increases, scanning lines and mosaic patterns become noticeable and the transmission quality is impaired. In particular, when transmitting a portrait like a videophone, it is not preferable because it causes discomfort to the other party, or in some cases the other party cannot be identified.

The present invention has been made in order to solve such problems, and makes it difficult to discard the data of the characteristic parts of the image (eyebrows, eyes, nose, mouth, etc. in the case of portraits). An object is to provide a video transmission device capable of improving transmission quality.

[0006]

A video signal transmission device according to the present invention transmits packet data containing video information and transmits the video signal connected to a communication network which may discard the transmission packet data according to a predetermined condition. The apparatus is provided with a feature extracting means for extracting a characteristic part of a video to be transmitted, and a discard condition assigning means for assigning a stricter discard condition to the packet data related to the characteristic part than the packet data related to other parts. It is characterized by doing.

[0007]

According to the present invention, when the packet data including the video information is transmitted, the characteristic extracting means extracts the characteristic portion of the video to be transmitted. The discard condition assigning unit assigns a stricter discard condition to the packet data related to the characteristic part than the packet data related to the other parts. Therefore, the data of the characteristic portion of the video is hard to be discarded, and the video transmission quality is improved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 2 is a schematic block diagram showing the configuration of the video transmission device of the present invention. The video signal captured by the TV camera 1 is input to the A / D conversion unit 51 of the transmission unit 50 of the video signal transmission device 5, converted into a digital signal here, and then input to the compression encoding unit 52, as described above. Digital data compression is performed. The compressed data is input to the ATM cell generation / transmission unit 23 and divided into cells.

On the other hand, the digital signal output from the A / D converter 52 is also input to the feature extractor 55, where the eyebrows, eyes, nose,
Features such as mouth are extracted. The feature extraction unit 55 itself may be a known one such as one that binarizes a digital signal to obtain a contour and recognizes the pattern, and one that obtains the eye position from the difference in brightness between white / black eyes. Good.
Then, the header information of the cell corresponding to the feature-extracted portion is written by the priority designating unit 56 so as to make the discarding inferior.

FIG. 3 shows a cell format. For the cell of the feature extracted portion, "0" representing the subordinate discard is written in the cell loss priority bit prepared in the 8th bit of the 4th byte of the 5-byte cell header. Note that "1" indicates priority disposal, and other than the characteristic part
Write "1". Such cells are ATM network 3
Will be sent to. Some cells are discarded due to traffic in the middle of the ATM network 3.

On the other hand, in the receiving section 57 of the video signal transmitting apparatus 5, the transmitted cell is decompressed into the original compressed data (there is a part missing due to traffic) in the ATM cell receiving / decompressing section 58,
Next, the decompression / decoding section 59 decodes it, and further the D / A conversion section 60 converts it into an analog signal, which is displayed on the monitor 4. The configuration of the receiving unit 57 is the same as the conventional one.

[0012]

In the video signal transmission apparatus having the above configuration, the cell loss priority bit "0" is written in the cell related to the video of the characteristic portion, so that the cell loss priority bit is discarded.
It is performed inferior to that of "1", and the probability that it will be received by the destination is high. Therefore, the image quality of the characteristic part is not easily impaired, and when the portrait is transmitted, the receiver is uncomfortable,
Never send an unrecognizable image of a person.

The present invention is not limited to portrait transmission, and the same effect can be obtained when applied to other images. Further, the device of the present invention is effectively applied not only to an ATM network but also to a communication network in which some data is similarly discarded.

[Brief description of drawings]

FIG. 1 is a block diagram of a conventional video signal transmission device.

FIG. 2 is a block diagram of a video signal transmission device of the present invention.

FIG. 3 is a format diagram of an ATM cell.

[Explanation of symbols]

 3 ATM network 5 Video signal transmission device 55 Feature extraction unit 56 Priority designation unit

Claims (1)

[Claims] 1. A video signal transmission device connected to a communication network, which transmits packet data containing video information and may discard the transmission packet data according to a predetermined condition,
A characteristic extracting means for extracting a characteristic portion of the video to be transmitted,
A video signal transmission device, comprising: a discard condition assigning unit that assigns a stricter discard condition to the packet data related to the characteristic part than the packet data related to other parts.