JPS62122484A - Picture information transmission system - Google Patents

Abstract

PURPOSE:To attain transmission with excellent transmission efficiency by providing the transmission mode utilizing the timewise correlation of a picture without increasing information representing the transmission mode in sending a picture group having a timewise correlation continuously. CONSTITUTION:When a mode decision circuit 107 sends only the mode information of the mode (e) or other mode, the outputted mode information is 1-bit digital data. Then (p) mode picture element data, (e) mode picture element data and (c) mode picture element data are obtained from buffers 108, 109 respectively and they are fed alternatively to a digital/analog (D/A) converter 12 by a switch 111. The switch 111 is connected to the position (e) when '1' level data is outputted from a terminal of the mode discrimination circuit 107 and connected to the position (-e) when a '0' level of data is outputted. Thus, with respect to the picture element block assigned to the mode (p), the basic picture element data of the present picture is sent and the discrimination of the mode (p) id executed at the reception side.

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 has already been announced. IIIF axis conversion 11? area compression method (hereinafter referred to as TA
T; Time Axis Transform) will be explained using a -dimensional case as an example.

Figure 6 is an illustration of the basic concept of TAT 6 The original signal is divided into predetermined periods as shown by the dotted lines, and r1 is used to determine whether the information contained in each divided block is coarse or dense. . For blocks with dense rl+ disconnections, all of the data obtained by sampling the original signal is transmitted as transmission data, and for blocks with coarse and I'l+ disconnections, only part of all the data is used as transmission data. , and other data shall not be transmitted as thinned data.

By the above-mentioned concept, the number of data transmitted per hour will be reduced, making it possible to compress the bandwidth of the transmitted signal.On the receiving side, these transmitted data are converted into thinned data. It is also used to form corresponding data.In other words, the thinned data becomes interpolated data that is T'J by performing an approximation calculation using the data transmitted at the time of reception.Also, this interpolated data is Since the fidelity of the restored signal to the original signal is almost unchanged compared to when all the data is transmitted, the fidelity of the restored signal is significantly reduced for one transmission band. In other words, 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 the sampling data or the - section of the data is made by examining the density state of the original signal, and the decision information is simultaneously transmitted as transmission mode information. Now, a case will be described in which the above-mentioned concept is applied to transmission of image information. Image information has a two-dimensional spread and is correlated both horizontally and vertically, so if not only the horizontal sampling interval but also the vertical sampling interval is variable, more effective transmission can be achieved. It becomes possible. This concept is hereinafter referred to as two-dimensional TAT, and will be explained in detail below. The basic concept of this two-dimensional TAT has already been disclosed in patent application No. 148112/1989 filed by Junto Kide. Figure @7 is a diagram showing the data transmission pattern in two-dimensional TAT. be. 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, the O mark indicates a transmission pixel, and the X mark indicates a thinning pixel. 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 E mode and C mode, respectively.

As is clear from the figure, C mode is 1/4 of E mode.
transmitted with an information density of

Regarding the thinned image J3 of the pixel block transmitted by C mode, on the receiving side, interpolated pixel data is formed using pixel data adjacent to it among the transmitted pixel data,
Restore.

A configuration for realizing such two-dimensional TAT transmission will be described below. FIG. 8 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 an interpolation circuit 3, and interpolated pixel data corresponding to one 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 conversion at, and it is determined whether each pixel block is to be transmitted in C mode or E mode. The mode discrimination circuit 4 is an A/D converter! Calculates the difference between the pixel data output from the pixel data and the interpolated pixel data, calculates the sum of this difference (hereinafter referred to as block distortion) for each pixel block, and stores this in memory for one field. .

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 constant. For example, if you set pixel blocks to be transmitted in C mode to 2/3 of the total and pixel blocks to be transmitted in E mode to 1/3 of the total, the total number of data to be transmitted (pressure 1if ratio) is (2/3Xl/ 4+1/
3X1=)l/2. Therefore, a 1,000-threshold value is determined based on the block distortion of all pixel blocks, which is '10, to determine the block distortion at which the C mode and E mode should be assigned.

Then, the stored block distortions are sequentially read out at the timing when the image signal of the ninth field is inputted, and are compared with the distortion threshold 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 the mode matches that of pixel blocks transmitted in the E mode, and the mode discrimination circuit 4 outputs the mode assignment as a mode discrimination signal.

As described above, the mode discrimination signal is supplied to the switch 7, and pixel data is selectively 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-to-analog (D/A) converter 8, where it is converted into an analog pixel signal and output to a transmission path. The mode discrimination signal is also outputted to the transmission path as a mote information signal via the buffer 9.

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 10. The output of the A/D converter 10 is supplied to the C mode interpolation circuit 11, and the interpolated data corresponding to the thinned out pixel data transmitted by the C mode is
11 is calculated.

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. All pixel data is read out from the frame memory 13 in an order based on, for example, a television signal, and output as an image signal via the D/A converter 14.

As mentioned above, in the two-dimensional TAT transmission system, image information can be transmitted extremely effectively.

<Problems to be Solved by the Invention> By the way, when the above-mentioned television signal is displayed, it is not a problem even if the resolution is poor in the moving image area of the playback screen 1111, In the +fI region, the deterioration in resolution is easily noticeable.

Therefore, it is said that there is a high correlation in the time axis direction for the 91 area of static + on one screen, and it is said that there is a high correlation in the time axis direction for the 91 area of static + on one screen.廿; 斤(r', ;(I'λ) However, in the two-dimensional TAT transmission system described above, when a group of temporally correlated screens are continuously transmitted, In this case, without making any particular distinction between the still image area and the moving image area on the screen, we also transmit the still image area, which has a high correlation in the time axis direction, and the rotation pattern for this area is also transmitted. The transmission efficiency was extremely poor because the image information was repeatedly transmitted over and over again.

Additionally, it is possible to create a new transmission mode that uses the correlation of images in the time axis direction, but in this case, increasing the types of transmission modes would increase the amount of transmission mode information to be transmitted. .

The present invention was made in view of the above-mentioned problems, and it is possible to improve the temporal correlation between screens without increasing the information representing the transmission form when sequentially transmitting a group of temporally correlated screens. It is an object of the present invention to provide an image information transmission system that can provide a transmission type m; that uses a transmission type m; and can perform transmission with high transmission efficiency.

Means for Solving the Problem> Under such an objective, the image information system of the present invention transmits a plurality of pieces of information having different information transmission densities to each of a plurality of blocks obtained by dividing one screen on the transmitting side. Transmission is performed by setting a transmission mode, and the receiving side has a hold T and a hold to hold the image information of the screen that has already been transmitted, and uses the image information of both sides that have been transmitted to form a reproduced screen. According to the present invention, there is provided a determining means for determining whether or not the image information held in the holding means is to be used.

[;When one screen is divided into blocks using the above-mentioned configuration and the current screen is transmitted to each of the plurality of blocks to form a reproduced screen, the image of the screen that has already been transmitted is By determining whether or not to use information using the image information of the transmitted screen, it is possible to provide a transmission form yE that utilizes the temporal correlation of the screen, and to perform efficient transmission. I can do it.

<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 can be The purpose is to further improve the image quality when transmitting data of .

The basic concept of this example will be explained below.
For a pixel block in the F area, if you transmit pixel data for the pixel block, when transmitting a subsequent screen, this pixel block will be transmitted first without transmitting the pixel data for that screen. The idea is to reuse certain data. The transmission mode in which the pixel data of the screen being transmitted in this way is not transmitted is hereinafter referred to as p mode, and in order to distinguish the transmission mode corresponding to E mode and C mode in 2D TAT from the case of 2D TAT. These are called C mode and C mode, respectively.

Considering the transmission of the same fake data 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 the C-mode. Therefore, as the static region increases, the number of pixel blocks that can obtain high resolution on the receiving side can be increased, and the 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 example, 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 dual image signal is analog digital (A/
D) The converter 100 converts it into a digital signal and outputs the data. 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). In addition, basic pixel data for transmitting p-mode mode information, which will be described later, is also generated here. 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. First, as in the case of two-dimensional TAT, the difference between the reproduced pixel data between the case of transmission in C mode and the case of transmission in C mode is calculated using the output of the A/D converter 100 and the interpolation circuit 1.
The block ↑Dc calculation circuit 103 calculates the sum of the differences (hereinafter referred to as block distortion Dc) for each pixel block.

On the other hand, the difference between each pixel data of the already transmitted screen stored in the frame memory 104 and each pixel data of the current screen is calculated, and the sum of this difference (hereinafter referred to as the sum of the differences for each pixel block) is calculated. fDl) is calculated by the block distortion DII calculation circuit 105. A comparator 106 compares these doors Dc and Dl.

That is, in the comparator 106, for each pixel block.

This means that it is detected which of the cases of transmission in C mode and the case of transmission in P mode can faithfully reproduce the screen compared to the case of transmission in C mode. Therefore, D.C.
>DB, the Cμ mode does not occur, and DC<, D), the p mode does not occur.

The comparator 106 outputs data indicating which of Dc and D) is larger (DC/D), and the mode determination circuit 107 uses these small force values as composite block distortion (Dm).
supply to.

In the mode r1 constant circuit 107, a predetermined number of C modes are assigned to each pixel block in descending order of Dm. Based on the distribution of Dm of
Find the threshold value of Dm, and use C mode if Dm exceeds this I, (I When D B>D c, C mode, D<Dc
When , p mote is allocated.

Accordingly, the mode determination circuit 107 assigns one of C mode, C mode, and P mode to each pixel block.

The mode information of the assigned mote is output. However, in this embodiment, since only the mode information indicating whether the mode is C mode or other mode is transmitted, the output mode information is 1-bit digital data, and the mode determination circuit 1
From 07 onwards, 1 bit data from the terminal, ie e/
Information data of e is output.

In other words, in this embodiment, the mote information to be transmitted is only 1-bit digital data indicating whether the mode is C mode or any other mode, and the mode information indicating whether the mode is C mode or P mode is not transmitted. For pixel blocks assigned to p mode on the screen, the basic pixel data of the current screen is transmitted so that the p mode can be determined on the receiving side.

In this way, by transmitting basic pixel data even for pixel blocks assigned to p mode, compatibility with two-dimensional TAT is maintained. Even if it is determined that (), decoding in C mode can be performed using basic pixel data in P mode, so the reproduced image will not be corrupted.

Therefore, the basic pixel data of the current screen can be obtained by performing the same thinning process as in the case of obtaining C-mode pixel data using the thinning circuit lot for all the pixel data of the current screen that has been manually A/D converted. .

P mode pixel data, C mode pixel data, and C mode pixel data are respectively obtained from the buffers 108 and 109 in which pixel data generated based on the six modes are stored as described above, and are selectively digitalized by a switch 111. The signal is supplied to a digital analog (D/A) converter 112.

The switch operation of the switch 111 is controlled by mode information data outputted from the mode determination circuit 107. In other words, the switch 111 is the mode determination circuit 10
When data 1'' is output from terminal 7, it goes to the e side in the figure.

When the data of °"O" is output, it is connected to the i side in the figure.

In this way, since 1-bit mode information data is output from the terminal of the mode determination circuit 107 as described above, pixel data corresponding to the mode information data is stored in the buffers 108 and 109.
is supplied to the D/A converter 112.

Further, the mode information data is 1-bit data indicating whether the mode is C mode or not, and is transmitted via the packer 110.

From F1. [- Separation device t for each mode in the above embodiment
Let's explain about 4K. Figure 2 shows block distortions Dl and D.
The figure which shows motor assignment with respect to C.

FIG. 3 is a diagram showing changes in the division ratio depending on the image shape.

In FIG. 2, regarding Dc and DB of pixel blocks, the greater the movement of the block, the greater the value of D%. Also. The part with higher definition, that is, the block with higher two-dimensional frequency, D
The value of C becomes thicker. Also, Dm is the smaller value of Dc and Dllll, which is Dm when a perpendicular line is drawn to D9 car, and a perpendicular line is further drawn to the DC axis from the intersection of this perpendicular line and the straight line D c = Dg. value.

Now, when the 0m axis is provided in FIG. 2 and 11 thresholds are considered, the threshold T2 is located as shown in the diagram in the Dc and D deafness coordinates, and determines the C mode area. That is, generally, pixel blocks with rapid movement and high definition are transmitted in C mode.

Figure m3 shows the case where the data compression rate for one entire screen is fixed at 1/2 regarding the allocation ratio of each mode. Here, it is assumed that the pixel data transmitted in the p mode is 1/4 of the total and equal to that in the C mode, so the number of pixel blocks that can be transmitted in the 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 between the front and rear screens, the same processing as two-dimensional TAT will be performed. On the other hand, when transmitting completely silent 1) two screens, 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 A in the diagram.
It is indicated by the length of the line segment of the portion that intersects with each region e, c, and p on the dotted line indicated by . As is clear from the above description, the position of this dotted line A 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 digimole 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 transmitted in any other mode, interpolated pixel data interpolated by the interpolation circuit 204 is output from the i side shown in the figure. In this way, the switch 205 outputs the transmitted pixel data to the frame memory 206 for all pixels.

-・The switch 209 is used to control the pixel block transmitted in C mode (the thinning circuit for thinning out only the pixel data -2)
For pixel blocks transmitted in other modes, basic pixel data is output as is. Note that this switch 209 is also controlled by the transmitted mode information. Therefore, the basic pixel data is output from the switch 209, and the basic pixel frame memory 2
The main meeting will be held on 01.

However, since the transmitting side shown in Figure 1 does not transmit mode information regarding C mode and p mode, the receiving side must determine whether the transmitted pixel block information is C mode or p mode. , the frame memory 201
, 206 must be prohibited for pixel blocks transmitted in p mode.

A method for determining C mode and p mode on the receiving side will be described below.

As mentioned above, on the transmitting side, basic pixel information is transmitted for pixel blocks assigned to either C mode or P mode, so on the receiving side, the difference between the previous screen and the current screen regarding 1ljf basic pixel information is transmitted. When the absolute values are determined and accumulated in block units (hereinafter referred to as basic pixel block Db), the distribution becomes as shown in FIG.

In Fig. 1O, Db(B) represents the distribution of basic pixel block distortion for a block where Dp is smaller than Dc, and nb(eK) represents the distribution of basic pixel block distortion for a block where DC is smaller than op. There is. Here, blocks with a smaller Dp in the former are cases where the correlation between the previous screen and the current screen is strong, and blocks with a smaller DC in the latter are cases where the correlation between the i11 screen and the current screen is weak, so this is the case. This results in a distribution of

Therefore, on the receiving side, for each block, the basic pixel block I
By calculating Db, setting an appropriate threshold (TH in the figure), and sorting based on the threshold TH, it is possible to obtain data (D c / D p) indicating which is larger, DC or Dp. This allows it to be determined whether a block that is not in C mode among the transmitted pixel block information is in p mode or C mode.

Therefore, 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 basic pixel block distortion Db, which is the sum of this difference, is calculated for each pixel block. The pixel block distortion Db calculation circuit 202 calculates it.

This basic pixel block distortion Db is supplied to the comparator 203, and if this Db is smaller than the threshold TH, it is determined that the pixel block has Dp smaller than Dc.

As a result, the information (D c / D p) representing the magnitude relationship between the output DC and Dp is converted into the transmitted mode information (
e/e) and an arithmetic circuit 210 to supply them to performance memories 201 and 206.

As a result, the 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 replaced 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 D.
When reading is performed on the /A converter 207, an analog image signal is output from the D/A converter 207.

As described above, it is clear that in the transmission system of the embodiment Δ above, a high-resolution analog image signal can be obtained for the stationary area.

In this embodiment, basic pixels are transmitted in the pixel block transmitted in P mode in the same way as in C mode, but the basic pixels are transmitted in a special pixel pattern, for example, all four pixels are black or white. It is also possible to transmit Da/Dp information by generating and transmitting on the transmitting side and detecting the special pixel pattern on the receiving side.Using the information of e/τ and Dc/Dp. When transmitting mode information indicating DC/mode, it is possible to configure a configuration in which pixel data of the 1111 screen is not transmitted. In this case, the change in the M''z ratio in each mode when the compression ratio is fixed at 1/2 is shown in diagram m5.

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 screens having temporal correlation, the time of one screen can be reduced without increasing the information representing the transmission form. It is possible to provide a transmission form that utilizes the correlation between images, and to provide an image information transmission system that can perform transmission with high transmission efficiency.

4. Brief explanation of the drawings: Figure 1 is a diagram showing a schematic configuration of the transmitting side of a transmission system as an embodiment of the present invention.

FIG. 2 is a diagram showing mote 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 ratio (l/I) of each mode in the case of 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 receiving 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. 10 is a diagram showing the distribution of basic pixel block distortion Db.

103---Block distortion Dc calculation circuit, 104.20
1.206---Frame memory, 105---Block distortion I) p calculation circuit, 106.203---One comparator, 107---Mode determination circuit, 202---One basic pixel block Distortion Db calculation circuit, 21
0---1 arithmetic circuit.

Figure 10

Claims (1)

[Claims] In a system that continuously transmits a group of temporally correlated screens, a plurality of information transmission forms with different information transmission densities are used for each of the plurality of blocks obtained by dividing one screen on the transmitting side. The receiving side has a holding means for holding the image information of the screen that has already been transmitted,
Image information transmission characterized by having a determination means for determining whether or not to use the image information held in the holding means by using the image information of the transmitted screen when forming the reproduced screen. system.