KR100207380B1 - Apparatus for reducing the data in motion picture - Google Patents

Abstract

The present invention relates to a shortening apparatus for a video terminal that uses a transmission band more efficiently by adding a shortening function to a video terminal. To solve this problem, the apparatus according to the present invention reduces a video signal provided from a video camera (CCD). A video signal encoding means for encoding the reduced video signal to generate a motion displacement and encoded video data, and outputting the encoded video data and the motion displacement data based on the video signal encoding means to the exchange or being provided from the exchange. And a terminal card for receiving the encoded image data and the movement displacement data, and a video signal decoding means for decoding the encoded image data and the movement displacement received from the exchange through the terminal card. Therefore, the limited transmission band can be utilized more efficiently.

Description

Shrink Device of Video Terminal

1 is a view schematically showing a connection state of a general terminal device and an exchange,

FIG. 2 is a view showing images of different conference parties output to the display device of the terminal device of FIG.

3 is a block diagram showing a condensation apparatus of a video terminal according to the present invention;

4 is a detailed block diagram of an encoder shown in FIG.

FIG. 5 is a detailed block diagram of the motion estimation unit shown in FIG.

* Explanation of symbols for main parts of the drawings

120: subtractor 140: reduction portion

160: encoder 180: motion estimation unit

200: terminal card 320: decryption unit

340: motion compensation unit 360: delay unit

380: Adder

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shortening device for a video terminal, and more particularly, to a shortening device for a video terminal, by adding a shortening function to a video terminal so that a transmission band can be used more efficiently.

Nowadays, more lively multi-party conferences are becoming more common while mutually exchanging video signals regardless of data transmission distance.

1 is a diagram schematically showing a connection state between a terminal apparatus and a switch, and includes a plurality of terminal apparatuses 10a to 10z including a video encoder, a video decoder, a display apparatus, a video camera, and the like. 10z) and an exchanger 20 interconnected with a selector 30 for controlling the exchanger 20.

That is, any terminal device (any terminal device of 10a to 10z) uses the image pickup device (not shown), such as a charge coupled device (CCD), etc. provided therein the video information of the meeting people After converting into an electrical signal, the image information corresponding to the converted electrical signal is encoded and then transmitted to the switch 20.

The exchanger 20 transmits the encoded video information to the terminal device of the other party's terminal device (any terminal device 10a to 10z), and decodes the encoded video information to output to the display device.

As shown in FIG. 2, the video output through the terminal devices 10a to 10z outputs video of different conference persons. That is, when the image signal received through the video camera of the corresponding terminal device (10a to 10z) of the corresponding terminal device is provided to the switch 20, the switch 20 is to receive the image input from the corresponding terminal device Multi-conferences are possible by integrating and then transmitting the video of the conference to each terminal device needed.

In more detail, the encoding process is performed by using a DCT (Discrete Cosine Transfomer) based on a cosine function for an image signal input from a video camera (not shown) included in a corresponding terminal device (a terminal device among 10a to 10z). ) And then quantize them. The quantized video frame is recovered by inverse DCT and inverse quantizer and then stored in memory, and the variable length coded frame I is transmitted to the exchange. Then, the reconstructed video frame (I) stored in the memory is the previous frame, and the difference signal obtained through the motion prediction and compensation between the currently input video frames is transmitted to the DCT conversion block, and the detected motion displacement (vector) is transmitted through the exchanger. Transmission to other terminal device.

Therefore, the predetermined terminal device decodes the received encoded video signal in a reverse manner from the encoding method, and stores the received video image in a memory, decodes the received motion displacement, and then decodes the received video signal based on the video signal stored in the memory. By performing motion prediction and compensation, the frame is decoded and then output to the display device.

At this time, the moving image terminal is configured to transmit the encoded image through the allocated transmission bandwidth as it is. As shown in FIG. Since it is the same as that, there is a problem of wasting bandwidth relatively.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a condensation apparatus of a video terminal configured to condense, encode, and transmit an input video signal in order to efficiently use an allocated transmission band.

In order to achieve the above object, an apparatus according to the present invention will be described below in detail with reference to the illustrated drawings.

3 is a block diagram of a condenser of a video terminal according to the present invention, which condenses an image signal provided from a video camera (CCD) (not shown), encodes the condensed image signal, and encodes a motion displacement and an encoded image. Image signal encoding means 100 for generating data, image data encoded based on the image signal encoding means 100, and motion displacement data are sent to the exchange 20 or encoded image data provided from the exchange 20. And a terminal card 200 which receives the motion displacement data, and an image signal decoding means 300 which decodes the encoded image data and the motion displacement received from the exchanger 20 through the terminal card 200.

The video signal encoding unit 100 obtains a difference signal between a subtracter 120 and a frame subtracted by the subtractor 120 for obtaining a difference signal between a video signal in units of frames provided from a camera CCD and a video signal whose motion is predicted and compensated. To the encoding unit 160 and the encoding unit 160 to encode the original image signal reduced by the reduction unit 140 by pre-filtering 2: 1 to the original image signal. The video signal predicted and compensated for the motion between the video signal encoded by the video signal and the frame video signal currently input from the camera (CCD) is provided to the subtractor 120 and the corresponding motion displacement data (Motion Vector) is transmitted to the terminal card 200. It consists of a motion estimation unit 180 to transmit to.

The terminal card 200 transmits the encoded video signal and the motion displacement data outputted from the video signal encoding means 100 to the exchanger 20 or outputs the encoded video signal and the motion displacement data inputted from the exchanger 20. Configured to transmit to the decryption means 300.

The video signal decoding means 300 uses a decoder 320 to decode the encoded video signal input from the exchanger 20 through the terminal card 200 and the motion displacement data separately provided from the terminal card 200. A motion compensator 340 for compensating for the motion of the decoded video signal transmitted from the decoder 320, a delay unit 360 for delaying motion compensation for the video signal decoded by the decoder 320, and motion compensation. And an adder 380 for adding the video signal compensated by the unit 340 and the video signal delayed by the delay unit 360 to output the image signal to the display device.

The apparatus according to the present invention thus configured is operated as follows.

First, an image signal in units of frames provided from a video camera (not shown) is provided to the subtractor 120 and the motion estimation unit 180 through lines A and Z.

If the subtractor 120 does not provide an image signal predicted and compensated through the line B from the motion estimation unit 180, the subtractor 120 does not directly calculate a difference signal for an image frame provided from a video camera (CCD). Transmission to the condenser 140. However, when the predicted and compensated image signal is provided from the motion estimator 180 through the line B, the difference obtained by subtracting between the predicted and compensated image signal and the image frame output from the video camera CCD is not shown. The signal is transmitted to the condenser 140.

The condenser 140 filters the video signal transmitted from the subtractor 120 to reduce the ratio by 2: 1 and transmits the image signal to the encoder 160.

As shown in FIG. 4, the encoder 160 includes a DCT 162, a quantizer 164, and a VLC 166. When the video signal shortened 2: 1 is applied from the reducer 40, The DCT 162 performs DCT processing in the same manner as the conventional method, obtains the DCT coefficient, quantizes the obtained DCT coefficient through the quantization unit 164, and outputs the variable length encoding by the VLC 166. At this time, the encoder 160 performs a coding process on the condensed video signal, so that the encoded video signal that is substantially output has data having a frequency band smaller than that of the conventional encoding. The encoded data is provided to the terminal card 200 through the line D.

As shown in FIG. 5, the motion estimator 180 may include an inverse quantizer 181, an inverse DCT 182, an adder 183, a frame memory 184, a motion predictor 185, and a motion compensator ( 186) to perform motion prediction and compensation processing. That is, if the data quantized by the quantization unit 164 included in the encoder 160 shown in FIG. 4 is provided to the inverse quantizer 181 through the line E, the quantization process may be performed in an inverse manner. Inverse quantization is performed to output dequantized data, which is inverse discrete cosine transformed in inverse DCT 182 and then provided to adder 183.

The adder 183 adds and outputs the inverse discrete cosine transformed data output from the inverse DCT 182 and the motion compensated image signal provided from the motion compensator 186. The output video signal is transmitted to the frame memory 184 and stored as a video signal corresponding to the previous frame.

Meanwhile, the motion predictor 185 predicts the motion between the current image frame input from the video camera CCD through the line A and the previous image frame stored in the frame memory 184, and is generated according to the prediction. The motion displacement is provided to the motion compensation unit 186. The motion compensator 186 compensates the previous frame stored in the frame memory 184 by the motion displacement provided from the motion predictor 185, and then provides the subframe to the subtractor 120 through the line B. At 200, the motion displacement data used is provided, and at the same time, a motion compensated image signal is provided to the adder 183. FIG.

Since the terminal card 200 outputs the encoded video signal and the motion displacement (vector) shorter than the original video frame to the switch 20, it is possible to transmit another data through the limited band.

On the other hand, when the encoded video signal and the corresponding motion displacement are applied from the switch 20, the terminal card 200 transmits the encoded video signal through the line F to the decoder 320, and the line H ) Provides the corresponding motion displacement data to the motion compensation unit 340.

The decoder 320 decodes the variable length coded data in an inverse manner as compared with encoding. The output decoded image is transmitted to the motion compensator 340 and the delay unit 360, respectively. The motion compensator 340 performs motion compensation on the video signal decoded by the motion displacement provided from the terminal card 200 to the adder 380, and the delay unit 360 transmits the decoded video frame by one frame. Delay in units then provided to the adder 380.

The adder 380 outputs an image frame obtained by adding the image frame delayed by the delay unit 360 and the compensated image signal provided from the motion compensator 340 to the display device.

As described above, the present invention has an effect of more effectively utilizing the transmission bandwidth by adding a reduction function to the video terminal.

Claims (4)

A system having a plurality of terminal apparatuses and an exchanger connecting the terminal apparatuses to each other: A video signal provided from a video camera (CCD) provided in the terminal apparatus is reduced, and the reduced video signal is encoded and moved. Video signal encoding means (100) for outputting displacement and encoded video data; A terminal card (200) for transmitting the encoded image data and the motion displacement data output from the image signal encoding means (100) to the exchange or receiving the encoded image data and the motion displacement data provided from the exchange; And a video signal decoding means (300) which decodes the received encoded video data using the motion displacement data received from the exchange in the terminal card (200). The video signal encoding means 100 of claim 1, further comprising: a subtractor 120 and a difference output from the subtractor 120 for obtaining a difference signal between a current frame and a motion predicted and compensated frame provided from the video camera; The condenser 140 to condense the signal, the encoder 160 to encode the image condensed by the condenser 140, and when the quantized video signal is transmitted from the encoder 160, decode and decode the image to the previous frame. Stored, the stored previous frame and the motion predicted and compensated frame for the current frame is output to the subtractor 120, and the motion displacement data generated during the motion prediction and compensation processing is transmitted to the terminal card 200 Shrinkage device of a video terminal, characterized in that consisting of a motion estimator (180). 3. The apparatus of claim 2, wherein the condenser 140 filters and condenses the video signal transmitted from the subtractor 120. The apparatus of claim 3, wherein the reduction ratio of the video signal generated by the reduction unit (140) is set to 2: 1.