SU1580590A1 - Method of transmission of television images - Google Patents

Abstract

The invention relates to television. The purpose of the invention is to reduce the distortion of the transmitted television images during the transmission of moving images. The goal is achieved by transmitting video information over two channels: the recovery channel and the measurement channel. The original video signal is digitized and memorized. To form a recovery signal, video information is read from memory devices and converted into a raster shape with a variable cell size. To form a change signal, use the difference between the color and brightness characteristics of the previous and current frames. The signal changes are also converted into a raster with a variable cell size, but the channel resolution is set depending on the rate of change of the image from frame to frame. Before outputting, video signals are converted to analog form. Together with the video signals, anchoring signals are transmitted to establish correspondence between the video signal elements and the frame elements. As a sync signal, a cyclic pseudo-random binary sequence is transmitted. 2 hp f-ly, 2 ill.

Description

The invention relates to the transmission of television signals and can be used in the transmission of television images over narrowband communication channels.

The purpose of the invention is to reduce the distortion of the transmitted television images during the transmission of moving images.

FIG. 1 shows an electrical block diagram of a transmitter portion of a device for implementing a method of transmitting television images; in fig. 2 is an electrical block diagram of the receiving part of the device for implementing the proposed method.

The method of transmitting television pictures is as follows.

When transmitting, the full television signal corresponding to the transmitted television image is divided into a video signal and a synchronization signal. The video signal is converted into digital form and the recovery video signal and the corresponding change signal and its change signal are formed from it. . By combining the recovery video signal and its associated anchoring signal, a recovery signal is obtained, and by combining the change video signal and corresponding

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Anchoring signal receives a change signal. In the event of a received signal, a recovery signal, a change signal, and a synchronization signal are transmitted separately over a narrowband communication channel. When receiving, the received recovery signal is divided into a recovery video signal and an associated lock signal, the received change signal is divided into a change video signal and a corresponding lock signal. The resulting video recovery signal is corrected by the change video signal received. The generated digital video signal is converted to analog form and combined with a synchronization signal to obtain a full television signal.

The transfer recovery video signal is formed from a digital video signal as follows.

In the corresponding digital video signal of a television image consisting of separate elements of a television image - elements of zero level, groups of identical elements that make up a portion of the television image of 2x2 zero level elements are found and replaced with one element of the first level. Then, groups of identical elements of the first level are found, constituting a portion of the television image of the size of the element of the first level, and are replaced by one element of the second level, etc. In this way, the entire television image corresponding to the digital video signal is processed. The element of the largest level can be formed by combining all the elements of a television image if the television image is a field of uniform color and brightness. The number of levels of television image elements is determined by the resolution of the television system in which the proposed method can be used.

The formation of elements of different levels is accompanied by the simultaneous formation of the corresponding lock signal. This signal is a sequential code in which the position and level of all the formed elements of different levels are encrypted.

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The video signal changes during transmission are generated in the same way as the recovery video signal is generated. However, the division into zero-level elements and the formation of elements of the first, second, and other subsequent levels in the television image corresponding to the differential digital video signal obtained by subtracting the digital video signal corresponding to the subsequent frame from the digital video signal corresponding to the previous frame of the television image. At the same time, a video change signal attachment signal is generated simultaneously.

Upon reception, a recovery signal is obtained from the recovery signal using information from the corresponding anchor signal. In the same way, the change signal is obtained from the change signal. As a result, all the elements of the television image corresponding to the recovery video signal and all the elements of the television image corresponding to the change video signal will be obtained. After this, the values of the video signals corresponding to the equally spaced elements of the television picture contained in the recovery video signal and the change video signal are folded and the change signal is corrected by the change signal.

Thus, the recovery signal conveys all the information about the television image with the maximum resolution determined by the value of the zero level element. Since the transmission of such a signal takes place over a narrowband communication channel, the transmission of one frame of the television image will take a long time. A separate change signal is transmitted to transmit the fast changes of the television image. Since it is also transmitted over a narrowband communication channel and its transmission completely with large changes in the television image will also take a lot of time, using the fact that the human eye during fast image changes is not able to perceive a high resolution image of a PV. time, in the change signal, elements of all levels are not transmitted, but

only the highest, i.e. the change signal is transmitted with a low resolution. This makes it possible to transmit the change signal fairly quickly and to obtain a change in the low-resolution television image also quite quickly. Then, as the resolution of the eye recovers, the change signal is also transmitted with increasing resolution. By the time of recovery, a high-resolution television image will be fully formed with a high-resolution eye.

To determine the resolution level of the transmitted signal of change, i.e. the minimum level of transmitted elements during the transmission of a change signal, establish a control period of 0.03– 0.3 s, determined by adaptive

properties of the eye. In case the transmission time of the change signal corresponding to the next frame of the television image is shorter than the time of the control period, i.e. the change signal at the transmitted resolution level carries little information, then the transfer of the change signal corresponding to the next frame of the television image is increased one level of resolution, and the beginning of the next control period begin from the moment of the beginning of the transmission of this frame. In case the transmission time of the change signal corresponding to the next frame of the television image is longer than the time of the control period, i.e. the change signal at the transmitted resolution level carries too much information, then the transfer of the change signal corresponding to the next frame of the television image is made with a lower resolution. At the same time, the transmission of the recovery signal corresponding to the next frame is simultaneously stopped, and the transmission of the recovery signal corresponding to the next frame of the television image begins.

In this way, fast-moving and fast-changing television images are transferred from

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low resolution, and the transmission of still and sedentary television images with high resolution.

The synchronization signal transmitted simultaneously with the recovery and change signals on a separate narrowband communication channel must determine the time position of each transmitted element of both the recovery signal and the change signal, therefore the synchronization signal is a cyclic pseudo-random binary sequence, the number of elements of which is chosen 1 to 2 times the number of elements of the transmitted television image. The same receive synchronization signal is used to generate the original clock signal.

The transmitting part of the device (Fig. 1) contains a video sensor 1, a generator of 2 clock pulses, the first 3 and second 4 counters, a register 5 lines, a register 6 frames, a first digital-to-analog converter (PAP) 7, a second CLP 8, an analog-digital converter (ADC) 9, frame memory block 10, reference signal memory block 11, video restoration signal memory block 12, change video memory signal block 13, first 14, second 15, third 16, fourth 17, fifth 18 and sixth 19 input registers, first 20, second 21, third 22, fourth 23, fifth 24 and sixth 25 exit registers, first 26th, second 27th, 29th and fifth

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third 28, even-30 address registers,

the first 31, second 32 regimen registers, the first 33 and second 34 registers of logical scales, the first 35 and second 36 registers of signal signals, the first register 37 of the resolution level code from the ability, the recovery signal generator 38 and the change signal generator 39.

The receiving part of the device (FIG. 2) contains the first 40 and second 41 switches, the signal converter 42

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bindings of the recovery signal, the converter 43 of the signal bindings of the change signal, priority block 44, block 45 of the change signal recovery, selector 46, memory block 47, seventh input register 48, sixth 49 and seventh 50 address registers, seventh output register 51, second A level 52 resolution code, a third DAC 53, a television indicator 54, a sweep unit 55 and an address correction unit 56.

The device works as follows.

The clock pulses produced by the generator 2 are converted into code sequences using the first 3 and second 4 counters, which through the register of 5 lines and the register of 6 frames corresponding to the first 7 and second 8 DACs control the scanning in video sensor 1 and determine the write addresses in memory block 10 ti frame using the first register address 26. At these addresses, the block 10 of the memory records the information received in the video sensor 1 and digitized in the ADC 9 information supplied to the block 10 of the memory via the first input register 14. This information in memory block 10 is continuously updated as it is received from video sensor 1. Shapers 38 and 39 receive information. From memory block 10, respectively, through the second 15 and third 16 input registers and the first output register 20 in the form code values of individual elements of the television image. The cell addresses of memory block 10, from which information is read into shapers 38 and 39, go to

 | memory block 10 through the second address register 27. In the formers 38 and 39, the elements of the first, second, etc. are formed. level To do this, imaging unit 38 and 39 compares the four elements adjacent to the television image that form a square cell, and if they are equal, replace these four elements of the zero level with one element of the first level, then compare the four elements of the first level that are adjacent to the television image. they form

 a square cell, and if they are equal, replacing these four elements of the first level by one element of the second level, etc.

Thus, in the imaging unit 38 and 39, the recovery signal and the change signal are respectively generated. These

 video signals through the second 21 and third 22 output registers and further through the fifth 18 and sixth 19 input registers are stored in memory blocks 12 and 13

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to the addresses received by these blocks through the fourth 29th and fifth 5th address registers. These addresses are formed in the driver 38 and 39 and are also supplied to the first 31 and second 32 registers of formats, to the first 33 and second 34 registers of logical scales, to the first register 37 of the resolution level code and through the third register 28 addresses to the block 11, in which the current processed in the imaging units 38 and 39 of the frame of the television image is stored, information about which is fed to the input of the block 11 of the memory through the fourth register 17 of the input. From the output of the memory block 11, through the fourth output register 23, this information is fed through the second 15 and third 16 input registers to the shaper 38 and 39. In the shaper 39, the change signal before forming the elements of the first, second, etc. The levels are used to calculate the difference between the values of each element of the television picture of the previous and next frames. Information about the previous frame is received from memory block 11. Coming from the first register 31 of formats and the first register 33 of logical scales to the first register 35 of the assignment signals information is stored in it and as an attachment signal before issuing to the narrow-band communication channel a restoration video signal from the memory block 12, from which this information is issued through the fifth output register 24, enters a narrowband communication channel. Similarly, an attachment signal is generated that corresponds to a change video signal. In addition, information about the level of resolution of the change video signal, the code of which is fed to the second register 36 of the binding signals from the first register 37 of the resolution level code, is added to this reference signal. In order to form the anchoring signal in the second register 36 of the anchoring signal, it also receives information from the second register of 32 formats and the second register of 34 logical scales. The change video signal is output to the narrowband communication channel from memory block 13 through the sixth output memory register 25 immediately after the corresponding anchoring signal is issued. The component information about formats and logical scales that are part of the signal completely and unambiguously determines the position on the television image of the image element and the number of its level, which ensures correct reconstruction of the television image on the receiving side.

A synchronization signal is generated in the form of a cyclic pseudo-random binary sequence, for example, an m sequence, which provides a small amount of transmitted data.

address correction and through the seventh, the address register 50 enters memory block 47. In this way, information is read from memory unit 47 independently of the process of writing to it.

The second register 52 of the resolution level code, receiving information about the level of resolution from the second switch 41, supplies the corresponding codes to the converter 43 and block 56, which ensures writing to the memory block 47 and reading

communication channel of information and high - $ of it on the television indicator 54

video signal forming the image with different resolution.

mechanical protection by a special generator (not shown; consisting of a shift register and a combination logic circuit and connected to a clock generator.

The recovery signal received at the receiving side using the synchronization signal is selected by the first switch 40 to the anchoring signal fed to the converter 42 and to the recovery video signal supplied through the selector 46 and the seventh register 48 of the input to the memory unit 47. Similarly Using the second switch 41, the change signal is selected on the lock signal supplied to the converter 43, and the change video signal, which through the change signal recovery block 45 is fed to the selector 46. The selector 46 uses the prior 44 block Theta selects the signal input to the seventh register 48 in the event that the recovery video signal and the video change signal are received simultaneously.In this case, the recovery video signal will be recorded first in memory block 47, and the video change signal will be delayed in the signal reconstruction block 45 In addition, in block 45, the change video signal is added by element with the contents of memory block 47, information from the output of which through the seventh output register 51 is fed not only to television the first indicator 54 through the third DAC 53, but also on the input unit 45. The third DAC 53 performs a transformation vanie digital video signal into analog video signals of three colors R, C, B

The scan signals in rows and frames are fed to a television indicator from the scanner unit 55. Simultaneously, the signal from block 55 through block 56

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in a video signal forming an image with different resolution.

Claims (3)

The synchronization signal, which arrives at the receiving part of the device, is decrypted using a shift register (not shown) and the sequence of codes defining the instants of transmission and, accordingly, reception of binding signals and video signals, is converted. Invention Formula 1, A television image transmission method in which, when transmitting, a full television signal of a transmitted television image is divided into a video signal and a synchronization signal, the video signal is digitized and transmitted over a narrowband communication channel, when received, the received video signal is converted into analog form and combined with a received synchronization signal, characterized in that, in order to reduce the distortion of the transmitted television images during the transmission of moving images, during transmission, after forming a video signal into a digital form, a recovery video output and its associated binding signal and a change video signal and a corresponding binding signal are generated from it, while the recovery video signal is formed from a digital video signal by converting it into a digital video signal corresponding to a raster of a television image with a variable size the raster element, the video change signal is formed by subtracting the digital video signal from the digital video signal corresponding to the previous frame a corresponding to the subsequent frame, and converting the resulting differential digit video signal to a digital video signal corresponding to a raster of a television image with a variable size of a raster element, while converting a digital video signal to a digital one, a video signal corresponding to a raster of a television image with a variable size of a raster element, is performed by replacing a group of identical elements of a television image - zero level elements of size 2X2 elements of a television image with one element of the first level, a group of identical elements of the n-th level, 2x2 in size element of the nth level, a single element of the n + 1 level, where yy is the level number, the resulting values of the signal values of the elements of all levels are combined into a video signal; an anchoring signal is obtained by generating a sequential code, whose position JB corresponds to the position on a television image with a variable size of a raster element of elements of all levels, they form a recovery signal by combining the recovery video signal and its corresponding binding signal into one sequence and the change signal and combining the video signal changes and the corresponding anchor BS signal in one sequence are transmitted on a narrowband communication channel separately reduction signal vsignel changes and the synchronization signal, when receiving the video signal before converting it to analog form from the received signal and the cor- reduction. are recited by the received signal of change by adding elements of the television image corresponding to the recovery signal 1580590 12 with the corresponding elements of a television, hot image corresponding to the change signal. 2. A method according to claim 1, characterized in that, when transmitting a change signal, a control period is set to 0.03-0.3 s, while at the time of transmitting the change signal corresponding to the next frame less than the control period, the change signal corresponding to the following frame is transmitted with a resolution that is increased by one level, and the next control period begins to be counted from the moment of the beginning of the transmission of the change signal corresponding to the next frame, at the time of transmission of the change signal corresponding to present the next frame, high control period, altering transmission signal corresponding to the next frame, and transmitting cease varying signal sootvetstvuyu5 conductive the next frame, with one level reduced resolution sposobno30 transmitting the next frame recovery signal and transmitting the next frame recovery signal. about tl and h and y5 3. The method according to claim., Y, and so that the synchronization signal before the transfer is converted into a cyclic pseudo-random binary sequence, and the ratio of the number of binary elements of the cyclic pseudo-random binary sequence to the number of TV image raster is chosen from 1 to 2, when received, the received cyclic pseudo-random binary sequence is converted into the original clock signal. 1 Into the channel