JPS62122480A - Picture information transmission system - Google Patents

Abstract

PURPOSE:To attain efficient transmission by storing picture information already sent in plural blocks obtained by dividing one picture and utilizing the held information when the present picture is not sent. CONSTITUTION:The transmission mode not sending picture element data of a sent picture is denoted by (p) mode and the transmission modes corresponding to the E mode and the C mode in a 2-dimentional TAT are denoted by (e) mode and (c) mode respectively, then the write/read on and from a frame memory 104 is controlled by each mode by using the mode information of the present picture assigned by a mode decision circuit 107 and the mode information of the preceding picture stored in a mode memory 115, but the specific mode change pattern where the transmitted picture quality is not improved and the transmission efficiency is lowered is inhibited. Thus, the block assigned to the (c) mode in the preceding picture is not assigned to the (p) mode in the present picture. Thus, the transmission with high transmission efficiency is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an image information transmission system, and particularly to an image information transmission system that continuously transmits a group of temporally correlated screens.

<Conventional technology> When transmitting information such as image information, the theme is always how to reduce the amount of information to be transmitted so that the original information can be faithfully reproduced. has been proposed so far.

In response to the above-mentioned theme, there is an adaptive variable density sampling method that appropriately changes the sampling density, that is, the density of transmitted information. An example of this method is the time axis conversion band compression method (TAT), which has already been announced.
AxisTransform) will be briefly explained using a -dimensional case as an example.

Figure 6 is an explanatory diagram of the basic concept of TAT, in which the original signal is divided into predetermined periods as shown by the dotted lines, and it is determined whether the information contained in each divided block is coarse or dense. . Then, for blocks that are judged to be dense, all of the data obtained by sampling the original signal is transmitted as transmission data, and for blocks that are judged to be coarse, only a part of all the data is used as transmission data, and the rest is thinned out. It shall not be transmitted as data.

The above concept reduces the number of data transmitted per unit time, making it possible to compress the bandwidth of the transmitted signal. These transmitted data are 1
It is also used to form data corresponding to thinned data. That is, the thinned data is interpolated data obtained by performing an approximate calculation using the data transmitted at the time of reception. In addition, since this interpolated data corresponds to coarse information, it is extremely similar to the thinned data, and compared to when all data is transmitted, there is almost no change in the fidelity of the restored signal to the original signal. It is possible to significantly compress the transmission band without causing any problems. That is, the amount of information to be transmitted can be reduced.

On the other hand, for each block, the decision as to whether to transmit all sampling data or a portion of the data is made by checking the density of the original signal, and the decision information is simultaneously transmitted as transmission mode information.

Now, we will explain the case where the above concept is applied to the transmission of image information. Since 0 image information has a two-dimensional spread and has correlation in both horizontal and vertical directions,
If not only the horizontal sampling interval but also the vertical sampling interval is variable, more effective transmission becomes possible. This concept is hereinafter referred to as two-dimensional TAT.

This will be briefly explained below. Furthermore, this two-dimensional TA
The basic concept of T has already been proposed in the patent application filed in 1986 by the present applicant.
-148112 etc.

FIG. 7 is a diagram showing a data transmission pattern in two-dimensional TAT. In 2D TAT, one screen is mX
The pixel block is divided into pixel blocks each consisting of n pixels, and the density of transmission data is changed for each pixel block.

In FIG. 7, it is assumed that the pixel block is composed of 4×4 pixels, and data transmission patterns are shown for the case where the block is transmitted in two types of transmission modes.

In the figure, O marks indicate transmission pixels, and x marks indicate thinning pixels. Furthermore, as shown in the figure, E indicates a pattern in which all pixel data is transmitted, and C indicates a pattern in which only a portion of all pixel data is transmitted. Hereinafter, the transmission modes based on these transmission patterns will be referred to as C mode and C mode, respectively.

As is clear from the figure, C mode is l/4 compared to C mode.
transmitted with an information density of

Regarding the thinned out pixels of the pixel block transmitted in the C mode, on the receiving side, interpolated pixel data is formed using pixel data adjacent to the transmitted pixel data and restored.

A configuration for realizing such two-dimensional TAT transmission will be described below. Figure ffJ8 is a diagram showing a schematic configuration example of the transmitting side of a transmission system using two-dimensional TAT. The example shown in FIG. 8 will be explained using an analog transmission system as an example.

The input analog image signal is sampled for all pixels by an analog-to-digital (A/D) converter l to generate digital all-pixel data. When this all pixel data is supplied to the thinning circuit 2, thinning processing corresponding to the C mode pattern shown in FIG. 7 is performed, and C mode pixel data is output. This C mode pixel data is supplied to the interpolation circuit 3, and interpolated pixel data corresponding to the thinned out pixel data is calculated.

This interpolated pixel data is supplied to the mode determination circuit 4 together with all the pixel data output from the A/D converter 1, and it is determined whether each pixel block is to be transmitted in C mode or in C mode. The mode discrimination circuit 4 calculates the difference between the pixel data output from the A/D converter l and the interpolated pixel data, and calculates the sum of this difference (hereinafter referred to as block distortion) for each pixel block. Store one field in memory.

Then, until the data of the next field is input, the block distortion distribution of all pixel blocks is determined. Here, in order to keep the compression ratio constant, the ratio between the number of pixel blocks transmitted in C mode and the number of pixel blocks transmitted in E mode must always be constant0. For example, if the pixel blocks transmitted in C mode are If the pixel blocks to be transmitted in 2/3 and E mode are set to 1/3 of the total, the total number of data to be transmitted (compression rate) is (2/'3 x 1/4 + 1/3
X1=)l/2. Therefore, based on the distribution of block distortion of all pixel blocks, a distortion threshold value for determining the block distortion at which the C-mode and E-mode mm measurements are to be performed is determined.

Then, the stored block distortions are sequentially read out at the timing when the image signal of the first field is inputted, and compared with the distortion value to determine the transmission mode. If the read block distortion matches the distortion threshold, C
A transmission mode is assigned so that the ratio of pixel blocks transmitted in E mode matches that of pixel blocks transmitted in E mode, and the mode discrimination circuit 4 outputs the index of the mode as a mode discrimination signal. .

The mode discrimination signal obtained as described above is supplied to the switch 7, and pixel data is alternatively read out from the buffer 5 for E mode pixel data and the buffer 6 for C mode pixel data. The output data of this switch 7 is input as transmission data to a digital/analog (D/A) converter 8, where it is converted into an analog pixel signal and output to a transmission line. Further, the mode discrimination signal is also outputted to the transmission line via the buffer 9 as a mode information signal.

FIG. 9 is a diagram showing a schematic configuration example of the receiving side of a transmission system using two-dimensional TAT. The pixel signal input through the transmission path and subjected to the above-described processing is converted into digital pixel data by the A/D converter IO. The output of the A/D converter 10 is supplied to a C-mode interpolation circuit 11, and interpolated data is calculated from the thinned-out pixel data transmitted in the C-mode.

On the other hand, the transmitted mode information controls the switch 12, and when the mode information indicates E mode, it is connected to the E side in the figure, and when it indicates C mode, it is connected to the C side in the figure. As a result, all pixel data including E-mode pixel data, C-mode pixel data, and interpolated pixel data are stored in the frame memory 13 (for example,
All pixel data is read out in an order based on the revision signal and output as an image signal via the D/A converter 14.

As described above, the two-dimensional TAT transmission system can transmit image information extremely effectively.

<Problems to be Solved by the Invention> By the way, when displaying the above-mentioned television signal, it is not a problem even if the resolution is poor in the moving image area of the ITF raw screen, but in the still area 11, both areas are Deterioration of resolution is likely to occur.

Therefore, for the still 1F image area on the screen, there is a high correlation in the time axis direction, and techniques for television signal processing that utilize this time axis direction correlation have been progressing in recent years.

However, in the above-mentioned two-dimensional TAT transmission system, even when sequentially transmitting a group of temporally correlated screens, it is difficult to distinguish between still and moving image areas on the screen. Still IE image areas with high correlation in the time axis direction will also be transmitted.

Therefore, similar image information is repeatedly transmitted over and over again in the static + 1 - information areas, which have very high correlation on the time axis, resulting in extremely poor transmission efficiency.

The present invention has been made in view of the above-mentioned problems, and when a group of temporally correlated screens is continuously transmitted, the information of that portion is The object of the present invention is to provide an image information transmission system that can eliminate the transmission of images and perform transmission with high transmission efficiency.

Means for Solving the Problems〉 Under these objectives, the image information system of the present invention has the following features:
A plurality of information transmission modes are provided for each of the plurality of blocks obtained by dividing one screen, including a transmission mode in which information on the current screen is not transmitted, and a holding means is provided for holding the image information of the already transmitted screen. When the current screen is not to be transmitted, the holding means is configured to prohibit rewriting of the image information of the block to which no information is to be transmitted.

Effect> With the above-described configuration, the information of the screen that has already been transmitted is held for each of the plurality of blocks obtained by dividing one screen, and the held information is used when the current screen is not transmitted. By using this, it is possible to transmit information in a highly efficient information transmission format.

<Example> An embodiment of the present invention will be described below.

In this embodiment, in addition to the above-mentioned two-dimensional TAT transmission system, the number of transmitted data is further reduced by utilizing the temporal correlation of image information, and it should also be called three-dimensional TAT. That is, in the transmission system using three-dimensional TAT of this embodiment, focusing on the fact that there is no need to update pixel data on the receiving side for static areas of the screen, the transmission system using three-dimensional TAT The purpose is to further improve the image quality when transmitting data of .

The basic concept of this embodiment will be explained below. Once all pixel data is transmitted for a pixel block in a static area, when transmitting a subsequent screen, the pixels of that screen will be without transmitting data,
The idea is to transmit data first and then use it repeatedly. The transmission mode in which screen pixel data is not transmitted in this way is hereinafter referred to as p mode, and 2
The transmission modes corresponding to E mode and C mode in dimensional TAT are referred to as C mode and C mode, respectively, to distinguish them from the case of two-dimensional TAT.

Considering the transmission of data at the same time as in the case of two-dimensional TAT, if the number of p-mode pixel blocks increases, among the remaining pixel blocks, pixel blocks with high information density can be transmitted in C-mode. Therefore, as the static 1-hi region increases, the number of pixel blocks that can obtain high resolution on the receiving side can be increased, and the reproduced image quality is further improved.

FIG. 1 is a diagram showing a schematic configuration of the transmitting side of a transmission system as an embodiment of the present invention, and in this embodiment, an analog transmission system is targeted.

Note that here, the data of the previous screen is shown by a thick line, and the data of the current screen is shown by a thin line.

The input analog image signal is analog/digital (A
/D) is converted into a digital signal '-) by the converter 100,
All pixel data is output. This all pixel data is supplied to the thinning circuit 101 as in the case of two-dimensional TAT, and
Thinning out corresponding to the mode pattern is performed to obtain C mode pixel data (basic pixel data). The C-mode pixel data is supplied to the interpolation circuit 102, and interpolated pixel data corresponding to the thinned-out pixel data is calculated.

Here, a process of determining which of the three modes e, c, and p should be used to transmit a pixel block will be described. The process can be roughly divided into two stages. First, as in the case of two-dimensional TAT, as in the case of two-dimensional TAT, the difference in 1 f current pixel data between the case of transmission in C mode and the case of transmission in C mode is calculated between the output of the A/D converter 100 and the interpolation circuit 102. The sum of these differences (hereinafter referred to as block distortion D) for each pixel block is calculated by using the output of
c) is calculated by the block distortion DC calculation circuit 103.

On the other hand, the difference between each pixel data on both sides already transmitted stored in the frame memory 104 and each pixel data of the 1M screen is calculated, and the difference is calculated in the same way. F Ll '111 and the block plan υ% regeneration circuit 105 calculate it.

Comparators 106 are used for each pixel block.

When transmitting in C mode and transmitting in P mode, it is detected whether the screen can be reproduced more faithfully than when transmitting in C mode. In this case, the smaller value of these is supplied to the mode determination circuit 107 as a composite block distortion (D m) together with data (DC/DLL) indicating the pμ strength.

Next, in the second step, the mode determination circuit 107 assigns a predetermined number of C modes to jl1 with a large Dm to each pixel block.This assignment procedure is the same as in the two-dimensional TAT described above. As in the case, D of all pixel blocks
A threshold value of Dm is determined based on the distribution of m, and when Dm exceeds this threshold value, it is set to C mode, and when Dm is smaller than the threshold value, it is set to a mode other than C mode. DmC mode,
When D @ < D c, p mode is assigned. Accordingly, the mode determination circuit 107 outputs data (e/e) indicating whether the mode is C mode or other mode, and D p/Dε.

Here, we will show how the mode changes depending on the transmitted image, and furthermore, how to use the already transmitted mode information.

Indicates whether the mode information to be transmitted from now on has been determined.

The images where the most noticeable effect of 3D TAT processing appears are:
If the entire screen is a static area for several frames,
In other words, it is a still picture. Here, taking 11 still images as an example, FIG. 1O shows a mode change pattern per screen from the first frame at the start of the system until the completion of full-area high-definition transmission.

In FIG. 10, the numbers in parentheses below the modes represent the proportion of blocks transmitted in that mode in one screen.

In the first frame, since no information is transmitted before that, P mode is not assigned and the two-dimensional TA
Same as T processing, 1, C mode is 2/3, C mode is 17
Allocated at a rate of 3.

Next, in the second frame, the block assigned to C mode in the first frame is
Since it is a Hi image, all the images change to the P mode (t1 in the figure), and the C mode of the second frame can be assigned to the area that was not in the C mode in the first frame.

In other words, among the blocks transmitted in C mode in the first frame, 1nI′i with a large Dc in the second frame period
Then, 1/3 of the total number of blocks is transmitted in C mode (t2 in the figure).

The remaining C mode remains the C mode (t3 in the figure).

In the third frame, the block (1/3 of the total number of blocks) assigned to C mode in the ff1Z frame also changes to C mode (upper 6 in the figure), that is, the p mode is transmitted as it is as p mode (in the figure (middle t4), the C mode changes to the p mode as described above (t5 in the figure), and in the end, the p mode alone occupies 2/3 of the total number of blocks, so the remaining l
/3 can be changed from C mode to C mode.

By the above procedure, all blocks can be reproduced in high-definition mode (C mode or P mode) in the fourth frame.

Also, if the still image state is maintained after the 4th frame,
The p mode and the C mode are respectively transmitted as they are (1y and te in the figure).

In this way, depending on what kind of transmission was performed on the previous screen,
By determining a transmission form that matches the current screen, efficient transmission becomes possible.

FIG. 11 illustrates an operation flowchart of the mode determination circuit 107 that determines mode assignment using the transmission mode of the previous screen.

In Figure 11, the mode information of the previous screen is utilized and the mode information of the current screen is determined in the first stage process in Figure 1, and the second stage is almost the same process as 2D TAT. will be held.

However, here, Dm is used instead of Dc in the C mode assignment as described above.

In other words, the mode determination circuit 107. After processing the second frame in Fig. 1θ, for blocks that have been transmitted in C mode or p mode up to that point, block distortion Dp and DC are compared in the first stage of Fig. 11, and depending on the result, C mode or p mode is assigned, and if C mode is assigned in the first frame, C mode is assigned, and in the second step of FIG. 11, assignment of C mode is determined by composite block distortion Dm. It's working.

The mode assignment operation shown in the flowchart of FIG. 11 is performed using the mode memory 115 shown in FIG. In other words, the mode memory 115 stores mode information for six frames in association with each block, and writes the mode information of frames to which mode assignment has been completed in order from the first frame. When determining the mode, first, the mode information of the previous screen is read from the mode memory 115, the mode information is determined, and if the mode is C mode or p mode, the block distortions Dc and Dp input from the comparator 106 are compared. p on the current screen depending on the result.
Then, the assignment of the C mode is determined based on the magnitude of the composite block distortion 0m value also input from the comparator 107.

The mode information of the current screen determined as described above is input to the mode memory 115, and the contents of the mode memory 115 are rewritten.

By the way, in the transmission system of this embodiment, only e/e mode information is transmitted. At this time, whether the transmission mode of a pixel block that is not in C mode is C mode or P mode is transmitted as pixel data as follows.

That is, for pixel blocks transmitted in p mode, basic pixel data of the previous screen reproduced on the receiving side is transmitted. Furthermore, all the pixel data of the front both sides reproduced on the receiving side is stored in the frame memory 104, and this is thinned out by the thinning circuit 108 in the same way as the thinning circuit 101. The output data of the thinning circuit 108 obtained in this way is hereinafter referred to as P-mode pixel data.On the receiving side, as will be described later, if the basic pixel data of pixel blocks are the same in consecutive screens, , 1 is determined to have been transmitted in p mode.

Note that the data stored in the frame memory 104 is the 7 pixel data of the previous screen that is reproduced on the receiving side, so the pixel data of the pixel block in which the previous screen is in p mode is replaced by the data 8 of the memory 104. must be prohibited. Also, for pixel blocks whose previous screen was in C mode, image quality improvement (no effect will be obtained) even if the previous screen is in C mode. In this embodiment, the mode determination circuit 10
Rewriting of the memory 04 is controlled by e/e obtained from 7.

Here, the write and read operations of the frame memory 04 mentioned above will be explained in detail.

In this embodiment, the writing and reading operations to and from the frame memory 04 are controlled for each mode based on the previous screen mode information stored in the mode memory 35 and the current screen mode information assigned by the mode determination circuit 107. As mentioned above, certain mode change patterns that do not improve the transmitted image quality and reduce transmission efficiency are prohibited, so blocks assigned to C mode on the previous screen are assigned to P mode on the current screen. In other words, 1 is assigned to p mode on the current screen.
14 screen and is assigned to p mode or C mode.

Further, the mode determination circuit 107 determines whether or not to allocate the p mode based on the block distortion Dp.

Since it is determined according to Dc, block distortion Dp.

When reading out the pixel data of the previous screen necessary for calculating Dc from the frame memory 104, the pixel data is read out in the 12th
As shown in Figure (a), it changes depending on the mode information on the previous screen.

FIG. 12(a) is a correspondence diagram between the mode information of the previous screen and the processing of pixel data stored in the frame memory 104. As shown in FIG. 12(a), reading from the frame memory 104 is performed according to the mode information of the previous screen, and the mode information of the current screen is assigned as described above. Note that, as shown in FIG. 12, when the mode information of the previous screen is C mode, reading from the frame memory 104 is not performed, so the value of block distortion Dp in the comparator 106 becomes larger, and in the current screen will no longer be assigned p mode.

Furthermore, writing of the pixel data of the current screen to the frame memory 104 is performed using the mode information t of the current screen determined as described above.
It is done according to Fi.

FIG. 12(b) shows the correspondence between the mode information of the current screen and the writing process of current pixel data to the frame memory 104.

As shown in FIG. 12(b), the pixel data of the current screen is not written to the frame memory 104 unless the mode information of the block on the current screen is C mode, so the pixel data is not updated, and the pixel data of the previous screen is remains memorized. Of this pixel data that is not updated, the pixel data of the blocks that have been assigned to p-mode is thinned out in the thinning circuit 108, and is output to the header 109 as p-mode pixel data for p-mode detection on the receiving side as described above. Ru.

As described above, p-mode pixel data, C-mode pixel data, and C-mode pixel data are obtained from the buffers 109 and 110, in which pixel data generated based on each mode is stored, respectively, and the switch 113 is set to e. /e and Dc/Dp are selectively supplied to a digital-to-analog (D/A) converter 114.

Therefore, analog pixel signals are transmitted from the D/A converter 114 using the three-dimensional TAT transmission system. Further, e/e is also transmitted via the buffer 112 as mode information.

The distribution ratio of each mode in the embodiment described above will be explained below. FIG. 2 is a diagram showing mode assignment to block distortion D% and Dc, and FIG. 3 is a diagram showing changes in the assignment ratio depending on the image state.

In FIG. 2, Dc and D% of a pixel block are μ. The larger the movement of a block, the larger the value of Dk. Also. The value of Dc becomes larger μ in a part with higher definition, that is, a block with a two-dimensionally higher frequency, and Dm takes the smaller value of Dc and D rut, so as shown in the figure, the position at <Xc Dc to do.

Dm of the pixel block with D% is a free line on the Dc axis. This is the value on the Dc wheel set when lowered directly to the perpendicular line.

T2 is located as shown and determines the C mode area.

That is, generally, pixel blocks with rapid movement and high definition are transmitted in C mode.

Figure 3 shows the allocation ratio of each mode when the data pressure ratio of the entire screen is fixed at 1/2. /4, which is assumed to be equal to that of C mode, so the number of pixel blocks that can be transmitted in C mode is always 1/3 of the total.

In FIG. 3, the portion D in the figure indicates the allocation ratio of the two-dimensional TAT. In other words, in a three-dimensional TAT transmission system, if there is no correlation at all between the previous and subsequent screens, two-dimensional TAT and one-time processing will be performed. On the other hand, when transmitting a completely still screen, the number of pixel blocks transmitted in C mode decreases, and the reproduced screen has the same resolution as when all pixel blocks are transmitted in C mode. The mode allocation ratio for a certain screen is indicated by the length of the line segment on the dotted line indicated by A in the figure, which intersects with the regions e, c, and p. As is clear from the above explanation, the position of this point mA depends on the temporal correlation of the image information to be transmitted.

FIG. 4 is a diagram showing a schematic configuration of the receiving side of a transmission system as an embodiment of the present invention. An analog pixel signal transmitted from the transmitting side shown in FIG. 1 is converted into digital pixel data in an A/D converter 200. switch 20
5 is controlled by the transmitted mode information, and for each pixel block, if transmitted in C mode, all pixel data is output as is.

If the pixel data is transmitted in any other mode, the interpolation circuit 204 outputs the interpolated pixel data from the i side shown in the figure. In this way, the switch 205 outputs all pixel data based on the transmitted pixel data to the all-pixel frame memory 206.

On the other hand, the switch 209 outputs only the basic pixel data of the pixel block transmitted in the C mode via the thinning circuit 208, and outputs the basic pixel data as is for the pixel blocks transmitted in other modes. Note that this switch 209 is also controlled by the transmitted mode information. Therefore, basic pixel data is output from the switch 209 and supplied to the basic pixel frame memory 201.

In addition, the difference between the basic pixel data output from the switch 209 and the basic pixel data of the previous screen obtained from the frame memory 201 is calculated, and the total of this difference (hereinafter referred to as block distortion Db) is calculated for each pixel block. The basic pixel block distortion Db calculation circuit 202 calculates it.

This block distortion Db is supplied to the comparator 203, and this D
If b is smaller than the threshold TH, it is determined that the pixel block has been transmitted in p mode.

This causes switches 205 and 209 to supply frame memories 201 and 206.

As a result, frame memories 201 and 206 can be rewritten by p
The pixel blocks transmitted in this mode will be prohibited, and the data of the previous screen will remain as is. If the data that has not been rewritten is e-mode pixel data, a good reproduced screen can be obtained.

In this way, the pixel data stored in the frame memory 206 for all pixels is updated, and the D/
By reading out the A converter 207, the D
The /A converter 207 outputs an analog image signal.

It is clear that in the transmission system of the above-described embodiment, a high-resolution analog image signal can be obtained in the static region.

In the transmission system of the above embodiment, the mode information indicating the P mode was not particularly transmitted, but it is also possible to transmit this and not transmit the pixel data of the previous screen. . FIG. 5 shows changes in the allocation ratio of each mode when the compression ratio is fixed at 172 in this case.

As is clear from the figure, even in this case, if there is no correlation between the front and rear screens, the same processing as the two-dimensional TAT is performed as shown at the bottom of the figure. In addition, in this case, if the correlation in the time axis direction is high, the number of pixel blocks transmitted in C mode increases.

<Effects of the Invention> - As explained above, according to the present invention, when sequentially transmitting a group of temporally correlated screens, part of the information of the already transmitted screens is used. It is possible to provide an image information transmission system that can eliminate the transmission of information in this portion and can perform transmission with high transmission efficiency.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a schematic configuration of a transmission side of a transmission system according to embodiments of the present invention. FIG. 2 is a diagram showing mode assignment to block distortions Dp and Dc. FIG. 3 is a diagram showing changes in the allocation ratio depending on the image state. FIG. 4 is a diagram showing a schematic configuration of the receiving side of a transmission system as an embodiment of the present invention. FIG. 5 is a diagram showing changes in the allocation ratio of each mode when transmitting p-mode mode information as another embodiment of the present invention. FIG. 6 is an explanatory diagram of the basic concept of TAT. FIG. 7 is a diagram showing a data transmission pattern in two-dimensional TAT. FIG. 8 is a diagram showing a schematic configuration example of the transmitting side of a transmission system using two-dimensional TAT. FIG. 9 is a diagram showing a schematic configuration example of the receiving side of a transmission system using two-dimensional TAT. FIG. 1O is a diagram showing mode transition when the entire screen is a static 11-picture area. FIG. 11 is a flowchart showing the operation of a mode determination circuit that determines mode assignment using the transmission mode of the previous screen as an embodiment of the present invention. FIG. 12(a) is a diagram showing the correspondence between each mode information of the previous screen and the read operation of the frame memory. FIG. 12(b) is a diagram showing the correspondence between each mode information on the current screen and the write operation to the frame memory. 103---Block distortion Dc calculation circuit, 104---
-Frame memory. 105---Block distortion np calculation circuit, 106---
-Comparator, 107--Mode determination circuit, 206--Mode memory. Figure L/-

Claims (1)

[Claims] In a system that continuously transmits a group of temporally correlated screens, it includes a transmission form in which information on the current screen is not transmitted to each of multiple blocks obtained by dividing one screen. A plurality of information transmission formats are provided, and a holding means is provided for holding image information of a screen that has already been transmitted, and when the current screen is not transmitted, the holding means rewrites the image information of the block to which information is not transmitted. An image information transmission system characterized by prohibiting.