JPS62175037A - Information transmission system - Google Patents

Abstract

PURPOSE:To execute the information transmission with a very satisfactory transmission efficiency by including the first mode to transmit representative data only obtained by coding representative information and the second mode to transmit the additional data obtained by forecasting-difference-coding the information of plural sample points existing at an information group. CONSTITUTION:When transmission is executed by an E mode, a usual quantizing bit number is given to C mode data (basic picture element data) not to execute the band limit, and the picture element data except basic picture element data are transmitted by the quantizing bit number less than it. Here, the additional picture element data are transmitted as the data obtained by nonlinear- quantizing the difference value with the basic picture element data. At field memories 25 and 26, E mode data and C mode data are respectively accommodated, and the E mode data are further guided to a switch 7 after through a forecasting difference coder 27.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an information transmission system, and in particular, a system for transmitting information for each group of information obtained by dividing information to be transmitted into predetermined amounts.
This invention relates to a system that transmits data by switching the information density.

<Conventional technology> When transmitting information, the theme is always how to reduce the amount of information to be transmitted (so that the original information can be faithfully reproduced), and to this end, a wide variety of transmission methods have been developed since then. Proposed.

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. As an example of this method, a time axis conversion band compression method (4 types) that has already been announced will be briefly explained below.

FIG. 5 is a diagram for explaining the basic concept of TAT. The original signal is divided into predetermined periods (predetermined amount of information) as shown by dotted lines, and it is determined whether the information contained in each divided group is coarse or dense. For groups 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 left as transmission data. shall not be transmitted as reference data.

By using the above-mentioned concept, the number of data transmitted per unit time is reduced, making it possible to compress the bandwidth of the transmitted signal. The data transmitted in this manner is used on the receiving side to form data corresponding to the thinned-out data. That is, interpolated data that approximates the thinned-out data is calculated using the transmitted data. Since this interpolated data corresponds to a coarse part of the information, it becomes data that is extremely similar to the thinned data. Therefore, compared to the case where all the data is transmitted, the fidelity of the restored signal to the original signal hardly changes, and the transmission band can be significantly compressed. In other words, the amount of information to be transmitted can be reduced.

On the other hand, for each block, the decision whether to transmit all sampling data or a portion of the data is made by examining the details of the original signal, and this decision information is also transmitted simultaneously in some form as transmission mode information. .

Now, let us consider applying the above-mentioned concept to the transmission of image information. Since image information has a two-dimensional spread and is correlated both horizontally and vertically, more effective transmission is possible if not only the horizontal sampling interval but also the vertical sampling interval is variable. becomes. This concept is hereinafter referred to as two-dimensional TAT, and will be briefly explained below. The concept of this two-dimensional TAT has already been proposed in the patent application filed in 1981-1481 filed by the present applicant.
It is disclosed in No. 12, etc.

FIG. 6 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. 6, it is assumed that the pixel block has 4×4 pixels, and two types of transmission modes are shown.

In the figure, ◯ indicates a transmission pixel, and × indicates a thinned-out pixel. E
As shown in the figure, C shows a pattern in which all pixel data is transmitted, and C shows a pattern in which only a part 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, it can be seen that the C mode performs transmission with an information density that is 1/4 that of the E mode.

Regarding the thinned-out pixels of the pixel block transmitted in the C mode, the receiving side forms interpolated pixel data using adjacent pixel data among the transmitted pixel data to restore the original screen.

A configuration for realizing such two-dimensional TAT transmission will be described below. FIG. 7 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. 7 is explained using a digital transmission system as an example.

The human-generated video signal is transferred to an analog-to-digital converter (A/
D) Sunblink all pixels at 1 to generate all pixel data. When this all pixel data is supplied to the thinning circuit 2, it is subjected to band limitation and then thinned out corresponding to the C mode pattern shown in FIG. 6 to obtain C mode data.

This C mode data is interpolation port i? This interpolated pixel data is supplied to mode discrimination circuit 4 together with all pixel data output from A/D 1. Then, it is determined whether each pixel block is to be transmitted in C mode or E mode. The mode discrimination circuit 4 calculates the difference between the pixel data output from the A/D 1 and the interpolated pixel data,
The sum of these differences (hereinafter referred to as block distortion) is calculated for each pixel block and stored in a memory for one field.

Then, until the data for the next field is input manually, the block distortion distribution of all pixel blocks is determined. Here, the ratio of the number of pixel blocks transmitted in C mode, the number of pixel blocks transmitted in Snake mode, and the number of pixel blocks transmitted in E mode must always be constant. For example, if you set the pixel blocks to be transmitted in C mode to 2/3 of the total and the pixel blocks to be transmitted in E mode to 1/3 of the total,
The total number of data to be transmitted (compression rate) is (2/3X
I/4+1/3Xl=)1/2. Therefore, the total threshold value for determining the degree of block distortion at which the C mode and C mode distribution should be performed is determined by dividing the block distortion of all pixel blocks by b.

Then, at the timing when the next field's video signal is manually input, the stored block distortions are read out sequentially and compared with the total threshold value to determine the transmission mode. If the read block distortion matches all thresholds, C
The transmission mode is determined so that the ratio of pixel blocks transmitted in C mode matches that of pixel blocks transmitted in C mode.

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 C mode data and the buffer 6 for C mode data. The output data of this switch 7 is output to the transmission path as transmission data.

Further, the mote discrimination signal is also outputted to the transmission line as mode information via the buffer 9.

FIG. 8 is a diagram showing a schematic configuration example of the receiving side of the two-dimensional TAT transmission system. The digital video signal that has been subjected to the above-mentioned processing and is input manually via the transmission line is sent to the C-mode interpolation circuit 1.
1, and interpolation data corresponding to the thinned-out pixel data in the C mode is calculated.

On the other hand, the transmitted mode information controls the switch 12,
When mode information indicates C mode, it is connected to the E side, and when C mode is indicated, it is connected to the C side. As a result, all pixel data including C mode data, C mode 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 outputted via a digital-to-analog converter (D/A) 14.

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

<Problems to be solved by the invention> In the two-dimensional TAT transmission system described above, it is possible to compress the band to the level of a station, but it is possible to transmit so-called high-definition television signals, which have been attracting attention in recent years. In this case, the amount of information per unit time increases to about five times that of the current NTSC television signal. Therefore, unless the amount of data is further reduced, it has been impossible to transmit it through a transmission line such as a magnetic recording/reproducing system.

In view of the above-mentioned background, it is an object of the present invention to provide an information transmission system that can further reduce transmitted information using the conventional variable density sampling method.

<Means for Solving the Problems> For the above purpose, the information transmission system of the present invention encodes representative information in an information group obtained by dividing information to be transmitted into predetermined amounts. a first mode in which only the representative data obtained by the method is transmitted, and a second mode in which additional data obtained by predictive differential encoding of information on a plurality of sample points in the information group using the representative data is transmitted together with the representative data. The configuration is such that information is transmitted by selectively using a plurality of modes including Mode 2 for each information group.

/Iノ「;田＼ According to the configuration described above, in addition to the effect of reducing the amount of transmitted information obtained by variable density sampling, the effect of reducing the amount of information by predictive differential encoding is The fidelity to the original signal can be obtained with almost no deterioration, making it possible to transmit information with extremely high transmission efficiency.

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

FIG. 1 is a diagram showing a schematic configuration of the transmitting side of a transmission system as an embodiment of the present invention. In the diagram, the same components as in FIG.

In the transmission system shown in Fig. 1, when transmitting in C mode, a normal quantization bit number is given to C mode data (basic pixel data) that has not been subjected to band/till limit, and the basic pixel Pixel data other than data (additional pixel) data is intended to be transmitted using a smaller number of quantization hits. Here, the additional pixel data is transmitted as data obtained by converting the difference value from the basic pixel data into a nonlinear matrix.

Field memories 25 and 26 each contain E mode data,
Although C mode data is stored, E mode data is further guided to switch 7 after passing through predictive differential encoder 27.

FIG. 2 is a diagram showing a specific configuration of the encoder 27 in FIG. 1.

The E mode data manually entered from the field memory 12 to the encoder 27 is supplied to the switch 37. The switching timing of the switch 37 is controlled so that it is connected to the A side when basic pixel data is manually input, and to the B side when additional pixel data is manually input. In this way, the basic pixel data is stored in the basic pixel buffer memory 38.
Then, the additional pixel data is written into the additional pixel buffer memory 39, respectively.

Here, the output data of the basic pixel buffer memory 38 becomes one of the inputs of the switch circuit 4I, and the output data of the basic pixel buffer memory 38 serves as one input of the switch circuit 4I.
0 is also supplied. The output data of the additional pixel buffer memory 39 is also provided to the DPCM encoder 40. The differential encoder 4o calculates the difference between the basic pixel data and the additional pixel data of four pixel data arranged in a square shape among all the pixel data in a grid shape as shown in FIG. 6, and then non-linearly quantizes them. The number of bits is reduced. For example, if each pixel data is 8-bit data, the output data of the differential encoder 40 is reduced to about 4 bits. Differential encoder 4
The output of 0 becomes the other power of the switch circuit 41, and this circuit 41 sequentially outputs 8-bit basic pixel data read out from the basic pixel buffer memory 38 and 4-bit differential additional pixel data read out from the differential encoder 40. do.

Incidentally, since the receiving side only performs the reverse process to that described above, a detailed explanation will be omitted.

Next, the data processing timing of each part will be explained. FIG. 3 is a diagram schematically showing the address numbers of data stored in the field memories 25 and 26 in FIG. 1. In the figure, i indicates the number of the 4×4 small block, and
As shown in Figure (a), for the E mode data in the small block with the small block number i, the address number of the upper left pixel, that is, the basic pixel, is E(i, 1), and the addresses of the upper right, lower left, and lower right pixels. The numbers are E (i, 2) and E (i, 3) respectively.
, E (i, 4). Also, C with small block number 1
The address number of the remote data is assumed to be C(i).

FIG. 4 is a flowchart showing the operation of transferring data to and from each memory shown in FIGS. 1 and 2. FIG. j is a small block number starting from j-0, and first, based on the mode information of that small block, it is determined whether the small block is a small block transmitted by C mode or a small block transmitted by E mode.

If it is determined that the mode is E, first connect the switch 37 in FIG. 2 to the A side, and then change the address number E (j, 1)
The basic pixel data of is written to the basic pixel buffer memory 38, and the switch 41 is set to the E side and the switch 7 is set to the E side. Next, after connecting the switch 37 to the B side, additional pixel data of address number E (j, 2) is written into the additional pixel buffer memory 39. Then, the differential encoder 40 converts E(j
, 2) and the basic pixel data of E(j, 1) are calculated, and the switch 41 is turned to B.
Connect to the side. Further, additional pixel data of E (j, 3) and E (j, 4) are sequentially written to the memory 39, and after the corresponding difference data is calculated, j=j+t is set and the next small block is processed. to go on a tour.

If the small block to be transmitted is determined to be C mode, read out the C mode field memory C(j), turn switch 7 to the E side, and then switch to 8 to process the next small block. go

These timings are, for example, the write and read timings of each memory controlled so that one piece of data is always outputted at the same interval from the switch 7.

By configuring as described above, the amount of transmitted data is (1/
3 x 5/8) + (2/3 x 1
/4) -9/24, and data compression of about 37% was possible.

In the above-mentioned embodiment, the method of predictive differential encoding was to non-linearly quantize the difference data between the basic pixel data and each additional pixel data in a (4x4) small block. However, the method of predictive differential encoding is not limited to this.

For example, for the additional pixel data on the upper right in a (4x4) small block, use the data of the difference between the average value of the two basic pixel data located on the left and right, and for the additional pixel data on the lower left, use the data of the difference between the average value of the two basic pixel data located on the left and right, and for the additional pixel data on the lower left, It is also possible to use the data of the difference between the average value of the two basic pixel data, and use the data of the difference between the average value of the basic pixel data located on all sides for the additional pixel data at the bottom right. . Also,
In the E mode, it is also possible to transmit C mode data and data of the difference between the C mode data and each pixel data.

In addition, in the above embodiment, each pixel block was configured to be transmitted in either C mode or E mode, but using the temporal correlation of images, data transmission is performed for the screen to be transmitted. It is also possible to provide pixel blocks with no pixel blocks. Details regarding this are disclosed in Japanese Patent Application No. 1982-230510 filed by Junto Kide.

Further, in the above-described embodiments, the information to be transmitted is a video signal, but the present invention can also be applied to the case where other information having some correlation on the time axis, such as an audio signal, is transmitted.

<Effects of the Invention> As explained above, according to the present invention, it is possible to obtain an information transmission system that can further reduce the amount of information to be transmitted than when transmitting information using the conventional variable density sampling method. Along with this, it has become possible to transmit a large amount of information per unit time over a relatively narrow band transmission path.

[Brief explanation of drawings]

FIG. 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 a specific configuration example of the encoder in FIG. 1, and FIG. FIG. 4 is a flowchart showing the operation of the I-receiving amount of data in each memory shown in FIG. 1 and FIG. 2. , Fig. 5 is a diagram for explaining information transmission using conventional variable density sampling, Fig. 6 is a diagram showing a data transmission pattern in two-dimensional TAT, and Fig. 7 is a diagram for explaining the transmission system using two-dimensional TAT. Fig. 8 is a schematic diagram of the receiving side of the two-dimensional TAT transmission system)
It is a figure showing an example of G composition. In the figure, 2 is a thinning circuit, 4 is a mode discrimination circuit, 7 is a switch, 38 is a basic pixel buffer memory, 39 is an additional pixel buffer memory, and 40 is a differential encoder.

Claims (1)

[Claims] a first mode in which a plurality of samples are taken for each information group obtained by dividing the information to be transmitted into predetermined amounts, and only representative data obtained by encoding representative information in the information group is transmitted; A plurality of modes are selectively used for each information group, including a second mode in which additional data obtained by predictive differential encoding of information on each sample point using representative data is transmitted together with the representative data. An information transmission system that transmits information.