KR0147777B1 - Video-signal transmitting and receiving apparatus and method thereof - Google Patents

Abstract

The present invention provides a system capable of performing transmission processing regardless of whether the TV signal on the transmitting side is a high resolution signal or a low resolution signal and receiving processing regardless of whether the receiving side is a high resolution display unit or a low resolution display unit.

On the transmitting side, the divider circuit divides the high resolution TV signal into a plurality of frequency band signals. The signals in each frequency band are converted into signals in the horizontal and vertical low range (low resolution TV signal bands). The transformed signal is coded by a coding unit that transmits the coded signal. At the receiving side, the coded signals multiplexed at the transmitting side are separated and decoded at the decoding unit. The frequency synthesis circuit restores the frequency band of the decoded signal to the original band. The resulting signal is then displayed as high resolution. The low resolution signal is coded and then transmitted. This coded signal is decoded at the receiving end. The decoded signal is interpolated in the interpolation circuit. The interpolation signal is then displayed on the high resolution display unit.

Description

Video signal transmission and reception device and method

1 is a block diagram of an embodiment of the invention.

FIG. 2A is a block diagram of a transmission apparatus according to the present invention, and FIG. 2B is a diagram showing an embodiment in which a frequency band is divided by a divider.

3A to 3D are diagrams illustrating a frequency band shifting process in the apparatus of FIG. 2A.

4 is a block diagram of the encoding unit of FIG.

5 is a block diagram of a decoding apparatus related to the present invention.

6 is a block diagram of the decoding unit of FIG.

7A to 7D are diagrams for explaining the operation of the apparatus of FIG.

8A to 8D are diagrams illustrating a frequency band shifting process in the apparatus of FIG. 6.

* Explanation of symbols for main parts of the drawings

106 to 109: selector 110 to 113 encoder

114: multiplexer 150: frequency divider circuit

201: Demultiplexer 202 to 205: Decoder

220: frequency synthesis circuit 240: screen synthesis circuit

270: interpolation circuit 290: high resolution display unit

300: channel selector 320: low resolution display unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal transmission and video signal reception apparatus in a video signal transmission and reception system for digitally high-efficiency coding processing of video signals such as television signals.

In general, a system has been used that processes high resolution television signals (hereinafter referred to as high resolution TV signals) with high efficiency coding and transmits the coded signals to allow the receiver to decode the transmitted signals. The high resolution TV signal is supplied to a high efficiency coding circuit in an HDTV (high definition television) encoder. The HDTV encoder consists of a high efficiency coding circuit and an output buffer. The high efficiency coding circuit processes the signal supplied from the input terminal with high efficiency coding and outputs the coded signal to the output buffer. The output buffer is a smoothing buffer which outputs the transmission signal at the transmission line at a constant transmission speed. If the amount of stored signal exceeds a certain value, the output buffer feeds the control signal back to the high efficiency coding circuit to reduce the amount of signal supplied from the encoding circuit. The constant speed signal supplied from the output buffer in the HDTV encoder is provided via the transmission line to the input buffer of the HDTV decoder. The HDTV decoder consists of an input buffer and decoding circuitry. The input buffer stores a signal provided from the transmission line and provides a decoding signal for a constant speed signal. After the signal provided to the decoding circuit is decoded, the decoded signal is supplied to the HDTV monitor and displayed.

In such a system, the high resolution TV signal provided through the input terminal is highly efficient coded in the HDTV encoder and then supplied to the HDTV decoder via a transmission line. The HDTV decoder decodes the signal supplied through the transmission line and then displays the decoded signal on the HDTV monitor.

In such a system, when a low resolution TV signal is received, the low resolution signal is once converted to a high resolution TV signal, and then the converted signal is transmitted on the same transmission line. If the display unit of the receiver is capable of only low resolution display, the transmitted high resolution TV signal must be decoded by the HDTV decoder and then this decoded signal must be converted back to a low resolution signal (down converter).

As described above, in the case of the conventional system of digital high efficiency coding processing of the high resolution TV signal before transmission, only the high resolution TV signal can be transmitted. For this reason, in order to use the existing television software, a low resolution TV signal must be converted into a high resolution TV signal at the transmitting end. If the display unit of the receiver can display only low resolution, a means (step) of decoding the received high resolution TV signal and converting the decoded signal into a low resolution signal should be provided.

Accordingly, an object of the present invention is to eliminate the disadvantages of the prior art, and to provide a video signal transmission and video signal receiving apparatus capable of transmitting and receiving not only a high resolution TV signal but also a low resolution TV signal.

In order to achieve the above object, when the high resolution image signal is supplied from the input terminal, the signal is divided by a two-dimensional (horizontal-vertical) filter, and then each of these divided signals is digitally encoded by the coding means. A video signal transmission method in which the coded signal is transmitted through a transmission line by high efficiency coding processing and a video signal reception method in which a high resolution receiver reproduces a high resolution video signal by decoding and synthesizing a signal obtained from the transmission line are provided. The invention also provides an apparatus for transmitting and receiving video signals for use in such a method.

The present invention also provides a video signal receiving method for reproducing a low resolution video signal by selecting and reproducing a signal encoded from horizontal and vertical low band signals of a signal divided by a two-dimensional filter, and receiving a video signal used in the method. Provide the device.

In addition, the present invention provides a video signal transmission method in which a high efficiency coding process is performed by encoding means when a low resolution video signal is supplied from an input terminal, and then the coding signal is transmitted through one of the transmission lines, and a high resolution receiver. The present invention provides a video signal reception method for reproducing a high resolution video signal by decoding a signal obtained from a transmission line into a high resolution signal. The invention also provides an apparatus for transmitting and receiving video signals for use in this method.

In addition, the present invention provides a video signal transmission method in which each video signal is digitally efficiently coded by an encoding means when a low resolution video signal is supplied from an input terminal, and then the respective coded signals are transmitted through a transmission line, and a high resolution. A receiver provides a video signal receiving method for decoding each signal obtained from a transmission line and simultaneously displaying the decoded low resolution video signal. The invention also provides an apparatus for transmitting and receiving video signals for use in such a method.

The present invention also provides a video signal receiving method for reproducing a low resolution video signal by causing a low resolution receiver to select and decode one of the coded signals, and a video signal receiving apparatus used in the method.

When the transmitting side transmits a high resolution TV signal by the above-described means, the high resolution TV signal is divided and the divided signal is transmitted through a plurality of transmission lines. When low resolution TV signals are transmitted, each low resolution TV signal may be transmitted via a transmission line. When the receiver is a high resolution receiver, a high resolution TV signal or an interpolated low resolution TV signal can be reproduced and at the same time a low resolution TV signal can be reproduced. When the receiving side is a low resolution receiver, a high resolution TV signal that cannot be easily reproduced in the past can be easily reproduced by selecting and processing horizontal and vertical low band signals. In addition, when a low resolution TV signal is encoded and transmitted, one low resolution signal may be selectively generated.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

1 is a block diagram of a video signal transmission and reception system according to the present invention.

First, the outline | summary of a video signal transmission apparatus is demonstrated. In this system, the high resolution TV signal is based on, for example, 1920 horizontal pixels and 1080 effective vertical scan lines, and the low resolution TV signal is based on, for example, 720 horizontal pixels and 480 effective vertical scan lines.

The high resolution TV signal is supplied to the video signal input terminal 101. In the present invention, the high-definition TV signal supplied to the video signal input terminal 101 is supplied to the division circuit 150 for dividing into four signal bands. Each divided signal is supplied to one input terminal of each selector 106 to 109, respectively. The other input terminal of each selector 106 to 109 is provided with image signal input terminals 102 to 105, respectively. The low resolution TV signals 1 to 4 are supplied to the input terminals 102 to 105, respectively.

The video signal obtained by the divider circuit 150 is divided into a signal almost equal to the frequency band of the low resolution TV signal whose frequency band is supplied to each of the input terminals 102 to 105 to be described in detail below. The video signals selected by the selectors 106 to 109 are supplied to the encoding units 110 to 113, respectively. The encoding unit then encodes the signal and supplies this coded signal to the multiplexer 114. The multiplexer 114 time division multiplexes each signal from the encoding units 110 to 113 to provide a multiplexed signal.

Next, a high resolution TV signal receiving apparatus will be described.

The received video signal is first divided for each encoding channel by the demultiplexer 201, which is then sent to the corresponding decoding units 202-205. If the signal decoded in the decoding units 202-205 is a high resolution signal, the decoded signal is frequency synthesized by the frequency synthesis circuit 220 to decode the original high resolution TV signal. This original TV signal is transmitted through the selector 280 and displayed on the high resolution display unit 290. When the decoded signal is a low resolution signal, the decoded signal is converted into a multi-screen video signal by the screen synthesizing circuit 240. The converted signal is then transmitted through selector 280 and displayed on high resolution display unit 290. Alternatively, if the decoded signal is a low resolution signal, one of the image signals output from the decoding units 202 to 205 is selected by the selector 260. This selected signal is converted into a high resolution TV signal by the interpolation circuit 270. The high resolution TV signal is transmitted through the selector 280 and displayed on the high resolution display unit 290.

Next, a low resolution TV signal receiving apparatus will be described.

The received video signal is selected by the channel selector 300. If the received video signal is a high resolution TV signal, the encoded signal is selected from the horizontal and vertical low frequency signals (signals in frequency band A in FIG. 2B) of the high resolution TV signal. This selected signal is decoded in the decoding circuit 310 and the decoded signal is displayed on the low resolution display unit 320. If the received video signal is a low resolution TV signal, the channel selector 300 selects a signal to be decoded. This selected signal is then decoded in decoding circuit 310 and the decoded signal is displayed on low resolution display unit 320.

Hereinafter, the video signal transmission apparatus will be described in more detail.

2a is a block diagram of a specific video signal transmission apparatus.

The video signal supplied to the video signal input terminal 101 is supplied to the vertical low pass filter (V-LPF) 151 and the delay circuit 169. The delay circuit 169 has the same delay amount as the V-LPF 151. The vertical low pass signal is obtained from the V-LPF 151. The subtraction circuit 152 performs an operation of combining the output signal of the V-JPF 151 and the output signal of the delay circuit 169 to generate a vertical high pass signal. That is, the input video signal is separated into a vertical low pass signal and a vertical high pass signal.

The vertical low pass signal from the V-LPF 151 is supplied to the horizontal low pass filter (H-LPF) 153 and the delay circuit 167. The delay circuit 167 has the same delay amount as the H-LPF 153. The subtraction circuit 155 performs an operation of combining the output signal of the H-LPF 153 and the output signal of the delay circuit 167 to generate a horizontal high pass signal. The horizontal low pass signal is obtained from the H-LPF 153. The vertical high pass signal from the subtraction circuit 152 is supplied to a horizontal low pass filter (H-LPF) 154 and a delay circuit 168. Delay circuit 168 has the same delay amount as V-LPF 154. The subtraction circuit 156 performs an operation of combining the output signal of the H-LPF 154 and the output signal of the delay circuit 168 to generate a horizontal high pass signal. The horizontal low pass signal is obtained from the H-LPF 154.

Ideally, the frequency bands of the separated video signals are arranged as indicated by A to D in FIG. 2B. Here, f _y and f _x represent the vertical frequency and the horizontal frequency, respectively. If the signals of A to D have the same frequency band as the low-resolution TV signal described above, the signals of frequency band B in FIG. 2b are modulated according to the frequency fs (cutoff frequencies of H-LPF 153 and 154) in FIG. It can be converted to horizontal and vertical low pass signals as shown in FIG. 3B. Similarly, signals in frequency band C of FIG. 2b can be converted to horizontal and vertical low-band signals, as shown in FIG. 3d, by modulating according to frequency fL of FIG. 3c (specifically, two of the interlaced signals). Line inversion processing or line inversion processing of interlaced signals). As such, the signals in frequency band D of FIG. 2B can be converted to horizontal and vertical low-band signals, such as frequency bands B and C, by modulating horizontally and vertically, as shown in FIGS. 3A and 3C.

The frequency shifting process shown in FIGS. 3A and 3B is performed in the horizontal modulation circuit 157, and the frequency shifting process shown in FIGS. 3C and 3D is performed in the vertical modulation circuit 158. Similarly, the frequency shifting process in the horizontal and vertical directions of the frequency band d in FIG. 2B is performed in the horizontal and vertical modulation circuits 159.

H-LPF 160, V-LPF 161, and H-V LPF 162 remove unwanted high frequency components caused by frequency modulation from the signals in each frequency band being processed as described above. These signals are then subjected to subsampling and thinning in down-sampling circuits 163 to 166.

Here, it is most important that the signals in frequency bands B, C, and D, which have become almost identical to band A as a result of modulation and the divided signals in frequency band A of FIG. 2b, do not generate horizontal and vertical aliasing signals. . The down-sampling frequency should be higher than 2fs, and the frequency bands of the V-LPFs 151, 161, 162 should be limited to prevent aliasing signals caused by thinning.

Therefore, the down-sampled signal is supplied to the selectors 106 to 109, and the low resolution TV signals from the video signal input terminals 102 to 105 are supplied to the selectors 106 to 109, respectively. The selectors 106 to 109 select the high resolution TV signal or the low resolution TV signal and supply the selected signals to the encoding units 110 to 113.

4 shows one of the encoding units 110-113. An input signal is supplied to a subtractor 170, which combines the input signal with a motion compensated one frame delay signal and subtracts it. The signal from the subtractor 170 is used as an interframe difference signal (prediction signal) that is DCT processed in the DCT unit 171. The signal thus processed is quantized in the quantizer 172. The quantized signal is divided into a zero execution signal and a level signal and supplied to the variable length coding circuit 178. The variable length coding circuit 178 Huffman codes the supplied signal. The coded video signal is supplied to an output buffer 179 which outputs the signal at a constant rate. On the other hand, the DCT coefficients quantized from the quantizer 172 are supplied to an inverse quantizer 174 which inverse quantizes the coefficients to almost recover the original DCT coefficients. This coefficient is then inverse DCT processed in inverse DCT unit 175 to decode it into a nearly original interframe difference signal. The decoded signal is added to the one-frame delay signal in the adder circuit 176 to nearly recover the original input signal. This input signal is delayed by one frame in the frame memory 177. The signal from the frame memory 177 is supplied to the motion compensation circuit 173 and the motion vector detection circuit 180. The motion compensation circuit 173 performs motion compensation on the output signal of the frame memory 177 based on the image motion vector sensed by the motion vector detection circuit 180. The compensated signal is supplied to the subtraction circuit 170 and the adding circuit 176 to generate the interframe difference signal. When the interframe difference signal is large, interframe coding is performed by turning off the switch 181.

In general, the encoding units 110 to 113 have the same structure, and motion vector detection and motion compensation are performed independently in each encoding unit. When the supplied and encoded signal is a signal obtained from frequency band division of a high-definition TV signal, the motion vector detection circuit of the encoding unit 110 to which the signal in the frequency band A of FIG. 2b (horizontal and vertical low pass signals at the start) is supplied. The motion vector detected by 180 may be provided to other encoding units 111-113. As a result, only the encoding unit 110 for encoding the motion vector is sufficient.

Thus, the encoded signals are combined in the multiplexer 114 shown in FIGS. 1 and 2a. In this case, the signal is multiplexed according to the code amount obtained from each encoding unit 110 to 111. If the signal to be encoded is a signal obtained from frequency band division of a high resolution TV signal, the signal in frequency band A of FIG. 2 delays the output of the addition circuit 305 by one frame in the frame memory 308 to motion this delayed video signal. By the motion compensation in the compensation circuit 307, it can be transmitted in the highest priority in consideration of the degree of contribution to the human vision. However, the one frame delay signal is supplied to the addition circuit 305 when the interframe signal processed coded signal is decoded. When the interframe signal processed coded signal is decoded, the one frame delay signal is blocked by the switch 306 so that it is not supplied to the adder circuit 305.

In FIG. 5, the decoded video signal is up sampled in up sampling circuits 221 to 224. In FIG. Upsampling is performed by inserting 0 into the signal of FIG. 7A as shown in FIG. 7B. 7A and 7B show the signal system in the horizontal direction. Similarly, zero line insertion is performed in the vertical direction. FIG. 7C shows the frequency band before upsampling, and FIG. 7d shows the frequency band after upsampling. In this manner, the upsampled signal is supplied to the horizontal demodulation circuit 225. The horizontal demodulation circuit 225 modulates the signal in the desired frequency band B in accordance with 3fs as shown in FIG. 8A so that the band signal is in the range of fs to 2fs. The horizontal band pass filter (BPF 228) removes the frequency band hatched in FIG. 8B from the modulated signal and converts it into a signal before coding. Similarly, the signal from decoding stage 214 is also upsampled. The vertical demodulation circuit 226 demodulates the signal thus processed every two lines or inverts each line to convert the signal of FIG. 8c into the signal of FIG. 8d. The inversion processing is used for the sequential TV signal every two lines, and the line inversion processing is used for the interlaced TV signal. In addition, the vertical BPF and horizontal LPF 229 limits the band of components that are hatched in FIG. 8d of the decoded signal. Similarly, the signal from the decoding stage 215 is up-sampled in the up-sampling circuit 224 and horizontal and vertical decoded in the horizontal and vertical decoding circuit 227, and the horizontal BPF vertical VPF 230 In the horizontal and vertical filtering process. The resulting signal after this processing is reproduced as horizontal and vertical high-band signals in frequency band D of FIG. 2b before coding. After the delays of the video signals in the bands A, B, C and D of FIG. It is added. The added signal is supplied to the selector 280 as a high resolution TV signal.

Since the signal processing when one or more low resolution TV signals are received is the same as in FIG. 1, description thereof will be omitted.

According to the present invention, when the input TV signal is a high resolution TV signal, one or more encoding units can be used as when one or more low resolution TV signals are supplied by dividing a frequency band and performing horizontal and / or vertical modulation. . Even if the receiver side is a low resolution receiver that could not be used for this purpose in the prior art, it is possible to easily decode the frequency band portion of the high resolution signal. Also, as a high resolution receiver, it is possible to reproduce high resolution TV signals, multiple display low resolution TV signals, and display screens of up-converted low resolution TV signals.

In the above embodiment, when the high resolution TV signal is divided as shown in FIG. 2B, the frequency bands A, B, C and D do not necessarily have the same bandwidth.

Additional advantages and modifications of the invention will be apparent to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details, elements shown and the embodiments described and illustrated herein. Accordingly, various changes may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (4)

In a video signal transmitting apparatus, an input terminal 101 to which a high resolution TV signal is supplied, a first signal having a first frequency band starting from 0 Hz, and second to fourth frequency bands, respectively, Frequency band dividing means 150 for dividing into second to fourth signals having a frequency shift, and frequency shifting to lower the second to fourth frequency bands to a first frequency band by frequency shifting the second to fourth signals. Means (157 to 159), down sampling means (163 to 166) for downsampling the first to fourth signals to lower the first to fourth frequency bands to a frequency band of a low resolution TV signal; Coding means (110-113) for coding the fourth to fourth signals, and outputting the multiplex signal by multiplexing the outputs of the first to fourth signals from the coding means. Song Means 114, wherein the video signal transmitting apparatus comprises: (i) a plurality of input terminals into which a plurality of low resolution TV signals corresponding to the first to fourth signals are input, in order to efficiently use a transmission line; (Ii) provided between the down sampling means and the coding means, and selecting one of a group consisting of the first to fourth signals and a group consisting of the plurality of low resolution TV signals, wherein the one of the groups And selecting means (106 to 109) provided to said coding means, said coding means having first to fourth coding selectors for coding each of said first to fourth signals, and said transmitting means , (Iii) a motion vector signal which is also used in the second to fourth coding selectors, and in particular, supplies a motion vector signal used in the first coding selector to the second to fourth coding selectors. And means (ii) motion vector transmitting means for transmitting said motion vector signal. The apparatus according to claim 1, wherein said transmitting means (114) time-division multiplexes a plurality of code signals obtained from said coding means (110-113). In a system comprising a TV signal transmitting apparatus and a TV signal receiving apparatus, the TV signal transmitting apparatus comprises: a first signal having a first frequency band starting from 0 Hz, and second to fourth frequencies of the high resolution TV signal; Division means for dividing into second to fourth signals each having a band; frequency shifting means for frequency shifting the second to fourth signals to lower the second to fourth frequency bands to a first frequency band; Down sampling means for down sampling the first to fourth signals to lower the first to fourth frequency bands to a frequency band of the low resolution TV signal, and first to fourth coding signals for the first to fourth signals; Coding means having a fourth coding processor, and transmitting means for multiplexing the first to fourth signals to generate a multiplex signal, and transmitting the multiplex signal; The TV receiver includes: receiving means for receiving the multiplex signal, separating means for separating the multiplex signal into coded signals corresponding to the first to fourth signals, respectively, and decoding the coded signal, respectively. Decoding means having a decoding selector for reproducing the first to fourth signals down-sampled, and an upsampling and frequency converting means for sampling and frequency converting the first to fourth signals to reproduce the high resolution TV signal. In order to use a transmission line efficiently, the TV signal transmitting apparatus includes (i) a plurality of input terminals to which a plurality of low resolution TV signals corresponding to the first to fourth signals are input, and (ii) the It is provided between a down sampling means and said coding means, and comprises a group consisting of said first to fourth signals and said plurality of low resolution TV signals. And selecting means (106 to 109) for providing one of said groups to said coding means, said transmitting means further comprising: (i) the second to fourth coding selectors; A motion vector signal supply means for supplying a motion vector signal used for the first coding selector to the second to fourth coding selector, and (ii) a motion vector signal transmission means for transmitting the motion vector signal. And the TV signal receiving apparatus comprises (i) the motor vector signal transmitted from the motor vector signal transmitting means in the first case that the TV signal receiving apparatus receives the high resolution TV signal. Vector processing means provided to the first to fourth decoding selectors, and (ii) synthesizing the low resolution TV signal so that the TV signal receiving apparatus receives the low resolution signal. Multi-screen image reproducing means for reproducing a multi-screen image in a second case; (iii) interpolation means for interpolating the one of said low-resolution TV signals after selecting said low-resolution TV signal in said second case; And selecting means for selecting one of an output signal output from said multi-screen picture reproduction means and an output signal output from said interpolation means in said second case. The high resolution TV signal is divided into a first signal having a first frequency band starting at 0 Hz and a second to fourth signal having the second to fourth frequency bands, respectively, and the second to fourth frequency bands being the first signal. Frequency-shifting the second to fourth signals to descend into one frequency band, down sampling the first to fourth signals to descend the first to fourth frequency bands into low-resolution TV signals, and performing a plurality of coding processes High efficiency coding the down-sampled signal to generate a predetermined signal, and finally, by time division multiplexing the plurality of coded signals, a first multi-coded signal is obtained, and a plurality of coded signals are generated to generate a plurality of coded signals. Images of a plurality of low-resolution TV signals obtained by high-efficiency coding and a second multi-coded signal obtained by time division multiplexing the plurality of coded signals A signal transmitting and receiving method, comprising: a first step of transmitting the first or second multiple coded signal, a second step of receiving the first or second multiple coded signal, and the first multiple A third step of time-division separating the first multiple coded signal into a plurality of coded signals corresponding to the first to fourth signals, respectively, when a coded signal is received; A fourth step of decoding the plurality of coded signals to generate a first step; a fifth step of upsampling the plurality of video signals to generate a plurality of upsampled video signals; A sixth step of frequency shifting into a frequency band, a seventh step of synchronizing the frequency shifted video signal with the up-sampled video signal that is not frequency shifted, and the second When the coded signal is received, an eighth step of aligning the plurality of video signals obtained in the fourth step on a screen, and one video signal is selected from the plurality of video signals obtained from the fourth step. And a tenth step of selecting interpolation, an output video signal obtained from the eighth step or an output video signal obtained from the ninth step, and supplying the selection signal to the high resolution display unit. Video signal transmission and reception method characterized in that.