JPS62149285A - Information signal transmission system - Google Patents

Abstract

PURPOSE:To reproduce a bit of information which generates a failure by discriminating a bit of transmitted transmission type information, detecting the proportion of a transmission type, and deciding whether a decoding process based on the bit of type information should be performed or not corresponding to the proportion. CONSTITUTION:At a mode control circuit 23, the number of blocks of reproduced signal dense group E modes and that of blocks of reproduced signal coarse group C modes are counted, and a mode information signal of one field is reproduced. And it is stored on a mode memory 27, and the proportion S1 of the number of blocks for an E mode and a C mode is calculated respectively. Also, assuming that the proportion for the E and the C modes allocated to each block at a recording side is set as S0, the S0 is compared with S1, and when they are coincided, it is decided that no errors are in the mode information signal, and when they are not coincided, it is decided that some errors are generated in the mode information signal. When the error exists, it is informed at a mode conversion circuit 28, and the mode information signal is read out from the memory 27, and all of one field is converted to the C mode. When it is decided as no error, a signal read out from the memory 27 is outputted as it is formed the circuit 28.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an information signal transmission/reception system for transmitting information signals.

[Conventional technology]

Conventional 1 For example, in an information compression transmission system, a time axis transform band compression method (Time Axis Transforma
tion (hereinafter referred to as TAT) has been announced,
This TAT method is a method for compressing and transmitting an information signal by utilizing the fact that the density of the information signal differs depending on the location when compressing the band of the information signal.

FIG. 2 shows the principle of using the TAT method in one-dimensional signal processing.

In FIG. 2, the original signal is first divided into predetermined amounts of information as shown by dotted lines, and it is determined whether the information is coarse or dense for each divided group. Then, in the group judged to be dense, all of the data obtained by sampling the original signal is transmitted as transmission data, and in the group judged to be coarse, only a part of all the data is used as transmission data. , and other data shall not be transmitted as thinned data. Note that in the figure, data indicated by an O mark is data to be transmitted (transmission data), and data indicated by an X mark is data not transmitted (thinned data).

By transmitting the transmission data indicated by O marks at regular intervals, the number of data transmitted per unit time is reduced, and the band of the transmission information signal is compressed.

The data transmitted in the manner described above is approximately restored using the transmitted data, which is the thinned-out data that was not transmitted during decoding, to obtain interpolated data (marked with * in the figure). In addition,
This interpolated data corresponds to areas where information is coarse and is restored as data that is very close to the thinned out data, so the amount of information does not change compared to when all data is transmitted, and the information signal This means that the transmission band has been significantly compressed.

At this time, whether all data is transmitted in each group,
The decision as to whether or not to transmit part of the data is made by examining the details of the original signal, and this decision information is simultaneously transmitted as a transmission mode information signal.

In the case of image information signals, not only the horizontal sampling interval but also the vertical sampling interval can be changed.
By performing two-dimensional processing, the transmission band of image information can be compressed.

When processing a two-dimensional signal such as an image information signal, one screen is divided into groups of m×n sampling points, and the density of the image is determined for each group. In the group judged to be dense, data obtained by sampling all of the sampling points is transmitted as transmission data, and in the group judged to be sparse, the data obtained by sampling only a part of the sampling points is transmitted as transmission data. The data that has been removed will be transmitted as transmission data, and the other data will not be transmitted as thinned data.

Here, suppose that the case where all of the sampling points are sampled is called the E mode, and the case where only a part of the sampling points are sampled is called the C mode.
The relationship between the sampling points that are transmitted and the sampling points that are not transmitted in each sampling mode is as shown in FIG.

FIG. 3 shows sampling patterns of E mode and C mode at 4×4 sampling points, where (a) shows E mode and (b) shows C mode.

One screen of image information to be transmitted is divided into groups of 4 x 4 sampling points in order from the upper left to the lower right of the screen, and each group is divided into two groups of sampling points as described above depending on the density of the image.
Select a species sampling mode and perform sampling according to the selected sampling mode.

Figure ff14 shows that the child 1/video of 1 field in the NTSC system is divided into groups of 4 x 4 sampling points using the above method, and each block is set to E mode and C mode as shown in Figure 3. It is a diagram in which sampling modes of modes are assigned.

Note that 0 marks are sampling points that are transmitted, and X marks are sampling points that are not transmitted.

By transmitting the data of each sampling point sampled in this manner at regular intervals, the transmission band is compressed and transmitted.

Note that sampling points that are not transmitted are approximately reconstructed during decoding using data from nearby transmitted sampling points, so the actual amount of information does not change compared to when all data is transmitted, and the information This means that the signal transmission band has been significantly compressed.

[Problem that the invention seeks to solve]

However, in the TAT method described above, if an error occurs in the mode information signal on the transmission path during transmission, the amount of information transmitted differs depending on each mode, so the correspondence between the mode information and the transmitted information signal is Since a shift occurs and the information cannot be reproduced correctly, the reproduced information deteriorates significantly.

The present invention has been made in view of the above circumstances, and provides an information signal transmission/reception system that is not affected by the characteristics of the transmission path and is capable of reproducing information even if an error occurs in the format information indicating the transmission format. The purpose is to

[Means to solve the problem]

The information signal transmitting/receiving system of the present invention has a maximum kX9. An information signal composed of (kXi>2, k, l are positive integers) sampling points is m×n
(m×n>2, mn is a positive integer) sampling points are divided into small groups, and each group is provided with a plurality of transmission formats having different numbers of sampling points to be transmitted. is assigned to the group at a predetermined ratio, information on the sampling point in each group is transmitted together with transmission format information representing the transmission format based on the assigned transmission format, and the receiving side receives information from the transmitted format information. The transmission mode of the signal is determined, the ratio of each transmission mode is detected based on the determination result, and the decoding process is controlled based on the detection result.

[Effect]

As described above, by determining the transmitted transmission format information, detecting the ratio of the transmission format, and determining whether or not to perform decoding processing based on the format information according to the ratio, it is possible to prevent failure from occurring. information can be reproduced without any problem.

〔Example〕

The present invention will be explained below based on examples.

Here, as an embodiment of the present invention, a case will be described in which the present invention is applied to a VTR.

In addition, the information signal handled here is a signal obtained by component demodulating an NTSC television signal and time division multiplexing.
When dividing a field television screen into a plurality of groups, each group is made up of 4×4 sampling points.

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, the input analog video signal for one field is converted into a digital video signal by a digital-to-analog (A/D) converter 1, and is sent to a switch 2 and a pre-filter as an E-mode digital video signal. 3, is supplied to the mode determination circuit 4.

The filter 3 is a two-dimensional low-pass filter that removes high frequency components of the input E-mode digital video signal, and averages the digital video signal. Then, the E-mode digital video signal as shown in FIG. 3(&) averaged by the filter 3 is converted to the C-mode signal for 1/4 pixel by the thinning circuit 5 as shown in FIG. 3(b). A thinning process is performed on the digital video signal. The C-mode digital video signal processed by the thinning circuit 5 is stored in the fourth memory 6 and is also supplied to the mode determining circuit 4.

When the switch 2 is connected to the F side in the figure, the input E mode digital video signal is sent to the first
The input signal is supplied to the memory for storage, and when connected to the G side, the input signal is supplied to the switch 9. When the switch 9 is connected to the H side in the figure, the input signal is supplied to the second memory 10, and when it is connected to the I side in the figure, the input signal is supplied to the third memory 11.

Note that the switch operation of the switch 2.9 is controlled by various synchronization signals generated by the synchronization signal generation circuit 7. From the synchronization signal generation circuit 7, a horizontal synchronization signal synchronized with the input timing of one line's worth of input signals is inputted to the switch 2, and a pixel synchronization signal synchronized with the input timing of one pixel's worth of input signals is inputted to the switch 9. .

By operating the switches 2 and 9, the E-mode digital fist video signal as shown in FIG. 3(a) is divided into 4×4 pixels as shown by O2Δ in FIG. The memory 8 stores the signal corresponding to the pixel marked with a mark, and the second
The memory 10 stores signals corresponding to pixels marked with Δ, and the third memory 11 stores signals corresponding to pixels marked 0.

E-mode and C-mode digital video signals are input to the mode determination circuit 4, and after performing interpolation processing on the C-mode digital video signal, the E-mode digital video signal is output for each l group. Compare the image signal based on the signal and the image signal based on the interpolated f-C mode digital video signal, and if the error is larger than the set threshold, the E mode is selected, and if it is smaller, the C mode is selected.
A mode information signal is generated to assign a mode to the group. That is, this mode information signal is generated so that the E mode corresponds to a group of dense parts on the screen of one field, and the C mode mode information signal corresponds to a group of coarse parts.

Furthermore, in order to equalize the transmission time of video signals for one field, it is necessary to keep the ratio to the number of pixel blocks transmitted in C mode constant.

In the above case, for example, the compression rate of the transmission band is set to 1 as a whole.
/2, the proportion of C mode should be reduced to 2/2 of the total.
3. If the ratio of E mode is set to 1/3, the overall band compression rate is (% x % + 1 x station) = repair. Then, when allocating mode information signals to each group, the error information of all the groups stored is arranged in descending order of error, and the top 17
Set a threshold such that E mode is assigned to 3.
This threshold value is compared with the error information, and if the error information signal is larger than the threshold value, E mode is assigned, and the settings are made so that E mode and C mode are transmitted at the above ratio. Ru.

The mode information signal generated in mode setting circuit 4 in this manner is stored in mode memory 12.

FIG. 6 shows an example of the arrangement of mode information signals set as described above on the screen, and the arrangement of pixels on the screen to be transmitted according to the mode information signals arranged in this way is The result will be as shown in Figure 7.

However, as mentioned above, what is actually transmitted is all the basic pixels of each block of the screen as shown in FIG. 8 and information on additional pixels of the block set to E mode as shown in FIG. Basic pixel information is stored in the third memory 11 and fourth memory 6, and additional pixel information is stored in the first memory 8. Since the information is divided and stored in the second memory 1O, the information stored in these memories is outputted in the form shown in FIG. 9(red) in accordance with the mode information.

Below, the first memory 8゛, the 'th memory 10. Third memory 11. The operation of outputting the sixth reading book 1 from the fourth memory will be explained.゛Since the mode information signal generated in the mode determination circuit 4 is stored in the mode memory 12, the memory control circuit 13 reads out the stored mode information signal from the mode memory 12. is the memory control circuit 13. Address calculation circuit 14. The signal is supplied to the switch 15.

The memory control circuit 13 receives a basic pixel information signal in E mode from the third memory 11 according to the input mode information signal,
A basic pixel information signal in the C mode is supplied from the fourth memory 6 to the switch 15, and a switch operation is also performed in accordance with the mode information signal, and a basic pixel information signal as shown in FIG. 8 is supplied to the switch 17.

In addition, the address calculation circuit 14 calculates the read address of the first memory 8 and the second memory 10 according to the input mode information signal, and controls the output of data from these two memories. When the E mode is specified in the mode information signal, the address of the pixel data to be output is calculated and output, and when the C mode is selected, the address is changed so that a predetermined amount of pixel data is skipped. The pixel data thus read out by the address calculation circuit 14 is supplied to the switch 16.

The switch 16 is a switch that is switched for each line in synchronization with the horizontal synchronization signal generated from the synchronization signal generation circuit 7, and this switch operation causes the output of the switch 16 to change to the 9th line.
The additional pixel information signal becomes as shown in the figure, and the switch 17
supplied to

The switch 17 is a switch that is switched every 0.5 field in synchronization with the synchronization signal generated by the synchronization signal generation circuit 17, and the signal outputted by this switch operation is divided into basic pixel data and basic pixel data as shown in FIG. Additional pixel data is separated, output in time series, and digital/analog (D
/A) The signal is supplied to the converter 18, converted into an analog signal again, band-limited via the low-pass filter (LPF) 19, and then recorded in the recording unit 20 together with the mode information signal.

As described above, the image information signal is transmitted after being divided into the basic pixel information signal for all divided groups and the additional pixel information signal of the group set to E mode. Even if the mode information signal is incorrect, it is possible to decode it using at least the information signal of the basic pixel.

FIG. 11 is a diagram showing a schematic configuration when the present invention is applied to a reproduction system of a VTR. The operation during reproduction will be explained below using FIG. 11.

In FIG. 11, the pixel information signal, mode information signal, and mode information signal reproduced by the reproduction section 21 are input to the A/D converter 22 and the mode control circuit 23, respectively.

The pixel information signal is converted from an analog signal to a digital signal by the A/D converter 22 and input to the switch 24 . The switch 24 has l reproduced in the reproducing section 21.
A synchronizing signal synchronized with the /2 field period is input, and this switch 24 separates the digital pixel information signal recorded as shown in FIG. 10 into basic pixel and additional pixel information signals. , each as a basic pixel memory 25
and stored in the additional pixel memory 26. The switching operation of the switch 24 is switched from the L side to the M side in the figure every 1/2 field period in synchronization with the synchronization signal.

On the other hand, the reproduced mode information signal is transmitted to the mode control circuit 23.
It is stored in the mode memory 27 at the same time as it is input into the mode memory 27. The mode control circuit 23 counts the number of blocks of each of the E mode and C mode among the reproduced mode information signals, and after one field's worth of mode information signals are reproduced and stored in the mode memory 27, the E mode Calculate the ratio of the number of blocks for each mode and C mode. This E
Let Sl be the ratio of the number of blocks in mode and C mode.

In addition, as mentioned above, the ratio of E mode and C mode allocated to each block on the recording side is, for example, if the compression rate of the transmission band is to be 1/2 as a whole, the ratio of E mode is 173, The proportion of C mode is predetermined to be 2/3 of the total. Let So be the ratio of the number of blocks in E mode and C mode.

Then, the So and 51 are compared, and when So and Sl match, it is determined that there is no error in the mode information signal, and when they do not match, it is determined that an error has occurred.

If the mode control circuit 23 determines that there is an error in the mode information signal, the mode control circuit 23 inputs an error detection signal to the mode conversion circuit 28 , and the mode conversion circuit 28 stores the error detection signal in the mode memory 27 . The mode information signal is read out, and all the signals for one field are converted into C mode signals. In addition, the mode control circuit 23
When it is determined that there is no error in the mode information signal, the signal read from the mode memory 27 is outputted from the mode conversion circuit 28 as it is.

The mode information signal output from the mode conversion circuit 23 as described above is transmitted to the basic pixel memorialless control circuit 29. It is input to the additional pixel memory address control circuit 30. Further, from the mode control circuit 23, a basic pixel memory address control circuit 29. A memory read clock signal synchronized with the mode information signal is input to each of the additional pixel memory address control circuits 3o, and the address control circuit 29
．． 30 is a basic pixel memory 25.30 according to the input mode information signal. Each stored pixel information signal is read out from the additional pixel memory 26.

Note that the basic pixel information stored in the basic pixel memory 25 includes E mode information and C mode information. Therefore, the switch 31 interpolates the basic pixel information of the C mode in the C mode interpolation circuit 32 using the transmitted pixel information, and then stores the basic pixel information of the E mode in the field memory 33 as it is. I'll do what I do.

In other words, the reproduced mode information signal that has been subjected to error detection processing is input to the switch 31, and depending on the mode information, in the case of C mode, the signal goes to the C side in the figure, and in the case of E mode, the signal goes to the side shown in the figure. It is controlled so that it is connected to the E side inside.

As described above, after the pixel information signal for one field is stored in the field memory 33, it is stored in the field memory 33 by a synchronization signal synchronized with the 1/2 field period reproduced by the reproduction section 21. The pixel information signal for one field is read out as image information 4g and sent to the D/A.
The signal is converted into an analog video signal by a converter 34 and then output.

The present invention has been described above as an embodiment of the present invention.
Although the present invention has been described using an example of application to a video disc device, the present invention can also be applied to other recording/reproducing devices, communication devices, etc., such as a video disk device.

Furthermore, in the embodiment, one screen is divided into 4×4 sampling points per group, but the present invention can also be applied to other group configurations.

In addition, in this embodiment, when performing error detection of the mode information signal, it is determined that an error has occurred in the mode information signal if the SO and Sl do not match. It is also possible to set a predetermined threshold value for the difference between So and 81, and to determine that an error has occurred in the mode information signal when the difference between So and 81 is larger than the threshold value. In this case, it is effective when image information processed by an incorrect mode information signal appears to have less deterioration in image quality than image information processed by C-mode interpolation, and the setting of the threshold value depends on the nature of the image information being handled. It is best to take this into consideration.

As described above, according to the present invention, errors in the mode information signal can be detected in the transmission path during recording and reproduction of a VTR, and even if an error occurs, the deterioration of the transmitted information can be minimized.

〔Effect of the invention〕

As explained above, the present invention is not affected by the characteristics of the transmission path, and the form information indicating the transmission form is
It is possible to provide an information signal transmission system that can perform +, Δlf, ITI + 6-.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of an embodiment of the present invention in which the present invention is applied to a recording system of a VTR. FIG. 2 is a diagram showing the principle of using the TAT method in one-dimensional signal processing. FIG. 3(a) is a diagram showing an E-mode sampling pattern at 4×4 sampling points, and FIG. 3'#(b) is a diagram showing a C-mode sampling pattern. Figure 4 shows that one field of a television screen, which is a time-division multiplexed signal obtained by component demodulating an NTSC television signal, is divided into groups of 4 x 4 sampling points, and each group is divided into E mode and C mode. FIG. 6 is a diagram showing a case where sampling modes are assigned. Figure 5 is a diagram showing the correspondence between each of the 4 x 4 sampling points and each memory that stores information on each sampling point.6 Figure 6 shows an example of the arrangement of mode information signals on the screen. It is a diagram. FIG. 7 is a diagram showing the arrangement on the screen of sampling points to be transmitted in accordance with the mode information signals arranged as shown in FIG. FIG. 8 is a diagram showing the arrangement of sampling points of basic pixels among sampling points on the screen. FIG. 9 is a diagram showing the arrangement of sampling points of additional pixels among sampling points on the screen. FIG. 10 is a diagram showing a transmission form of information signals at sampling points of basic pixels and additional pixels. FIG. 11 is a diagram showing a schematic configuration of the reproduction system shown in FIG. 1. 21----one reproducing unit, 24.31----switch, 25----one basic pixel memory, 26----additional pixel memory. 23---mode control circuit, 27---mode memory, 28---mode conversion circuit. 29--One basic pixel memory address control circuit, 30-
--One additional pixel memory address control circuit, 32---One interpolation circuit, 33---Field memory.

Claims (1)

[Claims] On the transmitting side, an information signal composed of a maximum of k×l (k×l>2, k and l are positive integers) sampling points is transmitted by m×n (m×n>2, mn is a positive integer). The number of sampling points to be transmitted is divided into small groups for each sampling point, a plurality of transmission forms with different numbers of sampling points to be transmitted are provided for the group, and the transmission form is allocated to the group at a predetermined ratio. transmitting information on sampling points in the group based on the assigned transmission format together with transmission format information representing the transmission format;
The receiving side distinguishes the transmission form of the information signal from the transmitted form information, detects the proportion of each transmission form based on the judgment result, and controls the decoding process based on the detection result. An information signal transmission and reception system.