JPS6248887A - Information signal transmission method and its equipment - Google Patents

Abstract

PURPOSE:To perform a transmission suppressing a high frequency component by dividing information having picture elements multiplied (k) by (l) into blocks having picture elements multiplied (m) by (n), sampling them at every block with different frequencies and transmitting them with corresponding mode signals. CONSTITUTION:Old field share of all picture element information signals of an inputted analog video signal is converted to a digital video signal at an A/D converter 1. And it is stored as the signal of mode E at a field memory 2 in a state that one address is added on the signal equivalent to one line within one block. At a pre-filter 3, a process that the signal of mode E is thinned out to the signal of mode C having the share of 1/4 of the picture element is performed. At a memory 5, one address is added and stored on the signal equivalent to one line within one block against the signal of mode C. At a mode deciding circuit 4, the picture signal of mode E and the interpolated picture signal of mode C are compared at every block, and a mode information signal is generated so as to allocate an E mode to the said block when the error of them is larger than a threshold, and a C mode when it is smaller than that.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides information signals of an image consisting of kXt (k, t are positive integers) pixels for each m×n (m, n are positive integers) pixels. This invention relates to an information signal transmission method and apparatus that divides the image into a plurality of small blocks, samples each block at a plurality of different sampling frequencies, and transmits both the sampled image sampling signal and a mode signal corresponding to the sampling frequency. be.

[Conventional technology]

Conventionally, for example, in an information compression transmission method, a time axis transform band compression method has been used.
ation (hereinafter referred to as TAT) has been announced.

This TAT method is a method of compressing and transmitting information by taking advantage of the fact that the fineness of the image differs depending on the location when performing band compression of the image information signal.In other words, the entire screen is first coarsely sampled to determine the basic structure of the image. In this method, the pixels (basic pixels) representing the details of the image are extracted, and then the additional pixels (additional pixels) representing the details of the image are extracted from the remaining pixels, and these are rearranged at uniform time intervals for analog transmission. At this time, if the total number of basic pixels and additional pixels is made smaller than the original number of pixels, the information to be transmitted will be reduced and the band will be compressed.

Determination (mode setting) as to whether or not to transmit additional pixels is made by dividing the image into small blocks of m×n pixels and checking the density of the image for each of these blocks.

By the way, Figure 2 shows T when the signal is processed one-dimensionally.
This diagram shows the principle of the AT method. In the case of image information signals, if you change not only the sampling interval in the horizontal direction but also the sampling interval in the vertical direction and perform two-dimensional processing, the band compression effect can be further improved. can be improved.

The small block generally has a configuration of m×n pixels, but may also be a square block of n×n pixels. Here, the following explanation will be given using a square block of 4Xj pixel as an example.

First, the image to be transmitted is connected from the upper left to the lower right.
The image is divided into elementary blocks, a sampling mode is selected for each block according to the density of the image, and sampling is performed according to the shade.

Furthermore, pixels that are not sampled are interpolated and reproduced based on the correlation i between pixels using information on sampled pixels in the vicinity of lζ during demodulation after transmission. Note that the ratio between the number of pixels of the original image and the total number of sampled pixels is the compression ratio of the band.

The sampling mode selected at the time of sampling compares the original image with the image obtained by interpolating the information of pixels that cannot be sampled as described above, and selects a mode in which the error caused by the interpolation process is the largest in the entire image. The more patterns there are in this sampling mode, the better the image reproduction accuracy will be, but this will also increase the amount of code information that indicates which sampling mode the block was sampled in. Generally, full transmission mode (E mode) and thinning transmission mode (
Type 281 sampling mode (C mode) is used.

Figure 3 shows 4× in the sampling mode of Mon2fi type.
In the figure showing an example of a sampling pattern of four pixels, (a) shows an E mode sampling pattern, and (b) shows a C mode sampling pattern. Note that the ○ marks in the figure are pixels that are sampled, and the x marks are pixels that are not sampled.

The band is compressed and transmitted using the TAT method explained above, but since the sampling mode is different for each m×n pixel block in the 17 TAT method, the image sampling information and mode information of the block are Correspond and transmit.

By the way, in the past, the TAT Manshiki I as described above was used as an image.
From this, the image is divided into blocks of 4×4 pixels as shown in FIG. 4(a), a sampling mode is selected for each block depending on the density of the image, and sampling is performed for the selected sampling mode.

FIG. 4(a) shows one field of a television screen of the NTBO system divided into blocks of m×n pixels, and sampling modes of E mode and C mode are assigned to each block. Note that in the figure, ○ marks are sampled pixels, and × marks are unsampled pixels.

In this way, the pixels to be transmitted on one field screen are determined, and according to the mode information, the image sampling information is transmitted in blocks so that the transmission speed of the image sampling information is constant. .

The transmission order of block circle image sampling information is generally horizontal or vertical. 4) is a diagram showing a transmission arrangement when transmission is performed in the horizontal direction, (C) is a diagram showing the transmission arrangement in the case of vertical transmission, and (b) is a diagram showing the transmission arrangement when transmission is performed in the horizontal direction.

The symbols and numbers in (c) correspond to the symbols and numbers of pixels in (a), and are transmitted in the direction of the arrow in the figure.

[Problem that the invention seeks to solve]

However, in Figure 4 CI) and (c), if we focus on the positional relationship on the screen of the pixels that span between blocks, for example, the pixels near the boundaries of the blocks in Figure 4 CI)) and (c) 16 and pixel a (on the a1 diagram, they are separated by one pixel in the horizontal direction and four lines in the vertical direction, so the correlation between pixels in the vertical direction is particularly weak, and the amount of information between the pixels is In other words, there is a high probability that high frequency components will occur at the boundaries of blocks.Especially in the two-dimensional TAT method, the number of blocks is very large, so at the boundaries of each block, there is a high probability that high frequency components will occur. However, there is a risk that a large number of high frequency components may be included.

In addition, when transmitting image signals such as those mentioned above, if a transmission line with a narrow transmission band is used, the high frequency components will be significantly degraded, so signal transmission errors and noise are likely to occur. Since this is necessary, the cost is high.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an information signal transmission method and apparatus for transmitting information signals with a simple configuration while suppressing high frequency components.

[Means to solve the problem]

The information signal transmission method of the present invention transmits the information signal of an image consisting of kXA (k, t are positive integers) pixels by mxn (m, n
is a positive integer) Each pixel is divided into multiple small blocks, each block is sampled at multiple different sampling frequencies, and the sampled image sampling signal and a mode signal corresponding to the sampling frequency are transmitted together. In this apparatus, the image sampling signals are transmitted in accordance with the order in which the pixels on the image are arranged in the horizontal direction.

Further, the information signal transmission device of the present invention transmits the information signal of an image consisting of kXA (k, t are positive integers) pixels m×n (m, n
is a positive integer) Each pixel is divided into a plurality of small blocks, each block is sampled at a plurality of different sampling frequencies, and the sampling signal on the sampled image and the mode corresponding to the sampling frequency are A device for transmitting signals together with a storage means for storing the image sampling signal, a readout means for reading out the stored image sampling signal from the storage means in accordance with the order in which pixels on the image are arranged in a horizontal direction, and a transmission means for transmitting signals.

[Effect]

As mentioned above, it is possible to suppress the transmission head component of the image sampling signal and reduce the occurrence of transmission errors, noise, etc. on the transmission path.

〔Example〕

The present invention will be explained below based on examples.

As an embodiment of the present invention, a case will be described in which the present invention is applied to a VTR. Here, when one field of a television screen in the M'rSO system is divided into a plurality of blocks, each block is made up of 4×4 pixels.

FIG. 1 is a diagram showing a schematic configuration when the present invention is applied to a recording system of a VTR.

In FIG. 1, an input analog video signal for one field is converted into a digital video signal by a /D converter 1, which converts all pixel information signals for one field into a digital video signal, which is sent to a field memory 2 and a brifilter 3. , mode determination circuit 4
supplied to

The digital video signal is stored in the field memory 2 as an E-mode digital video signal with one address added to a signal corresponding to one line in one block.

The filter 3 converts the E-mode digital video signal into an amount of information equivalent to the C-mode digital video signal, as shown in FIG.
The E-mode digital video signal as shown in a) is thinned out into a C-mode digital video signal of 174 pixels as shown in b). The trout 0 mode digital video signal processed as described above in the flash filter 3 is sent to the mode determination circuit 4 and the memory 5.
supplied to

In the memory 5, one address is added to a signal corresponding to one line in one block of the C mode digital video signal and stored.

E-mode and C-mode digital video signals are input to the mode determination circuit 4, and after interpolation processing is performed on the C-mode digital video signal, each block is converted into an E-mode digital video signal. The PfJ line signal is compared with the image signal based on the interpolated C-mode digital video signal, and if the error is larger than a set threshold, the E mode is assigned, and if it is smaller, the C mode is assigned to the block. Generates an interrogation signal. That is, this mode information signal is generated so that the E mode corresponds to blocks in a dense area on the screen of one field, and the C mode mode information signal corresponds to blocks in a coarse area.

The mode information signal generated in mode determination circuit 4 is stored in mode memory 6 and simultaneously supplied to counter 7.

In addition to the mode information signal, a block synchronization signal is input to the counter 7. This block synchronization signal is a clock pulse synchronized with the length of a signal corresponding to the number of pixels in the horizontal direction of one block.The counter 7 uses the mosquito mode information signal and the block synchronization signal to first pulse the block synchronization signal. and E in the mode information signal.
When the mode is detected, the count value up to that point is output to the stamp memory 10, and after being output, it is reset. In other words, the count value corresponding to the number of C modes before the E mode block on the screen is the skip memory 10.
is memorized.

Further, a block synchronization signal and a horizontal synchronization signal are input to the address signal generator 8. The horizontal synchronization signal is a pulse signal synchronized with line scanning of the screen, and once the address signal generator 8 detects the pulse of the horizontal synchronization signal, it counts up every time a pulse of the block synchronization signal detected after that is detected. The value is outputted to the parallel millimeter converter 11 as lower address data.

The horizontal synchronization signal is also input to the initial value setting circuit 9, which generates upper address data corresponding to each line every time a pulse of the horizontal synchronization signal is detected and outputs it to the parallel-serial converter 11.

The serial-parallel converter 11 combines the upper address data and the lower address data generated in the above manner and inputs it to the skip memory 10 as the write address data of the skip memory 10. The count value output from the designated address 4CtJ7 is stored.

FIG. WE5 shows the correspondence between the mode information signal input to the mode memory 6 and the data contents written to the skip memory 1o. Note that the fifth factor (a) is when the mode information signal of the block corresponding to the left end of the line is E mode,
(b) is the case of C mode. Both (a) and (b)! The number I of C mode blocks existing before the mode block is stored as a value to which the number of E mode blocks ""1" is added.

Next, a procedure for rearranging the digital video color numbers into the transmission order as shown in FIG. 4(ci) will be explained.

The memory control circuit 16 continuously reads out the mode information signals stored in the mode memory 6 and simultaneously inputs them to the memory control circuit 13 and transmits them by detecting a horizontal synchronizing signal. The line identification circuit 12 determines whether the line is an odd number line or an even number line.
The identification signal is input.

When the identification signal indicating an odd line is input to the memory control circuit 12, the memory control circuit 12 selects the read address of the field memo 112 when writing if the mode information signal input from the mode memory 6 is 8 mode. The E mode digital video signal is read out continuously at 1/2 the speed of E mode. Further, in the case of C mode, read addresses of the memory 5 are continuously generated at the same speed as when writing, and a C mode digital video signal is read out and inputted to the switch circuit 15.

This switch circuit 15 is connected to the H side shown in the figure when the output from the AND gate 14 is at a high level (“H”), and converts the digital video signal read from the field memory 2 into the /A f converter 15. and low level ('
L'), it is connected to the L side shown in the figure, and supplies the digital signal read from the memory 5 to the /A converter 15.

A mode information signal from the memory 6 and an identification signal from the line identification circuit 11 are input to the AND gate.

2, the identification signal indicates an odd line (-L''), when the mode information signal is E mode (``H''), it is from field memory 2, and when it is C mode (@L''), it is from field memory 5. The digital video signal is switched from 4 to 4 as described above.
It is supplied to converter 15. Furthermore, when the identification signal indicates an even number line ("R"), the digital video signal from the field memory 2 is supplied to the D/Az converter 15 whether the mode information signal is E mode or C mode. Ru.

By the way, on an even number line, as shown in Fig. 4(a), C
There is no digital video signal present in the mode block. Therefore, in order to keep the data rate constant, the signals of the next two mode blocks are read out continuously.

First, in a block corresponding to the left end of the screen, the memory control circuit 12 specifies an address in the skip memory 10 that is L away from the block position and reads out its contents.

As mentioned above, the content of the skip memo IJ to is the number of blocks in C mode that exists before the block in mode 2 plus the number of blocks in E mode @1'', so it is difficult to read. The contents of the skip memory 10 that have been output are added to the initial value of the address of the field memory 2, the result is designated as the read address of the address of the field memory 2, and the digital video signal of the next 2% block is read out. From then on, every time an E-mode block is detected, the content of the address corresponding to the block position is read from the skip memory 1o, and the content is added to the address of the E-mode block in the field memory 2. The result is used as a read address to specify an address in the field memory 2, and the next E-mode block digital video signal is read out.

As described above, signal processing of odd and even lines is performed by the memory control circuit 15 in the field memory 2. Memory 5.
By controlling the reading of the skip memory 10, a signal with a constant data rate can be obtained, and the digital video signal processed in this way is converted into a 4-band signal by a temperament converter 16.
It becomes an analog signal compressed into
After the band is limited by the LPF 17, the recording section 18 performs recording processing together with the mode information signal output from the mode memory 6 and records it on a tape (not shown).

The above operation is performed in units of the number of pixels in the vertical direction of the block to be divided, that is, in this embodiment, 4 lines, so the mode information signal for each line is stored in the mode memory B, and the mode information signal for each line is J6 is read out from the mode memory 6 for each process.

FIG. 6 shows a schematic configuration of a VTR reproducing system for reproducing information 'M' recorded by the VTR recording system of FIG. 1.

In FIG. 6, the analog video signal is played back from a tape (not shown) in the playback unit 19 and the band is compressed to 1/2.The mode information signal is an analog video signal that is input to the /D converter 20 and converted into a digital video signal. converted to
A mode information signal is input to mode memory 21 and stored.

The digital video signal converted by the A/D converter 20 is input to the field memory 23, and writing to the field memory 23 is controlled by the write time control circuit 22.

The reproduced mode information signal is input to the write time control circuit 22, and when the E mode digital video signal is detected as the χ mode in the input mode information signal, the digital video signal is changed to the normal speed. When the C mode digital video signal is written in the field memory 23 in the summer and the C mode is detected in the mode information signal lζ, the digital video signal is written in the field memory 23tC at 1/2 of the normal speed.

The digital video signal written in the field memory 23 as described above is read out block by block by the readout control circuit 24 and input to the switch 25.

The switch 25 is switched in response to a mode information signal outputted from the mode memory 21 at the same time as the start of reading from the field memory 24. When the mode signal is E mode, the switch 25 is switched to the E side shown in the figure, and when the mode signal is C mode, it is switched to the 1 side. It switches to C@ as shown.

Then, the digital video signal read out from the field memory 23 in units of blocks is supplied to the field memory 27 as it is in the case of the viewing mode according to the mode information signal, and in the case of the C mode, the digital video signal is read out from the field memory 23 in units of blocks. The pixel information that was not transmitted is subjected to interpolation processing using the transmitted pixel information, and then supplied to the field memory 271, etc.

In the field memory 27, the digital video signal for one field is processed and stored as described above, and then outputted to the four converters 28 by the readout control circuit 24, converted to an analog video signal, and output as an output video signal. be done.

That's all W! ? The recorded analog video signal and mode information signal are then reproduced and returned to the same signal form as that input at the time of recording.

In addition, in the example! Although one screen is divided into blocks of 84×4 pixels, the present invention can be applied to other block configurations iζ
can also be applied.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide an information transmission method and apparatus for transmitting a duck alarm signal with a simple configuration while suppressing high frequency troubles.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration when the present invention is applied to a recording system of a VTR. FIG. 2 is a diagram showing the principle of the TAT method when a signal is processed one-dimensionally. FIG. 3(a) shows the pixel arrangement in E mode, and FIG. 3(a) shows the pixel arrangement in C mode. Figure 4(a) shows a one-field TV screen of the NTSC system divided into 4 x 4 pixel blocks, and each block is assigned the E mode and C mode sampling modes.Figure 1(b) ) is a diagram showing the transmission arrangement when image sampling information in a block is transmitted in the horizontal direction, (c) is a diagram showing the transmission arrangement when the information is transmitted in the vertical direction, and (a) is a diagram showing the transmission arrangement when the information is transmitted in the vertical direction. FIG. 2 is a diagram illustrating a transmission arrangement when transmission is performed by. Figure M5 is a diagram showing the correspondence between the mode information signal input to the mode memory 6 in Figure 1 and the data content written to the skip memory 10. If the mode information signal of the corresponding block is E mode, <b) is C mode. FIG. 6 is a diagram showing a schematic configuration of the reproduction system shown in FIG. 1. 2...Field memory 4...Mode determination circuit 5...Memory 6...Mode memory 7...Counter 8...Address signal generator 9...Initial value setting circuit 10...Skip Memory 12...line identification circuit 13...memory control circuit 15, φ, switch 18...recording section.

Claims (1)

[Claims] 1) An information signal of an image consisting of k×l (k, l are positive integers) pixels is divided into a plurality of small blocks for each m×n (m, n are positive integers) pixels. In a device that samples each block at a plurality of different sampling frequencies and transmits both the sampled image sampling signal and a mode signal corresponding to the sampling frequency, the transmission order of the image sampling signal is determined based on the pixel on the image. An information signal transmission method characterized in that the information signals are transmitted in the order in which they are arranged in the horizontal direction. 2) Divide the information signal of an image consisting of k×l (k, l are positive integers) pixels into a plurality of small blocks for each m×n (m, n are positive integers) pixels, and for each block, A device for sampling at a plurality of different sampling frequencies and transmitting the sampled image sampling signal together with a mode signal corresponding to the sampling frequency, comprising a storage means for storing the image sampling signal, and an image stored from the storage means. 1. An information signal transmission device comprising: reading means for reading out sampling signals corresponding to the order in which pixels on an image are arranged in the horizontal direction; and transmission means for transmitting the read signals.