JPS6258197B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal receiving device, and more particularly to a device for receiving video information that is transmitted line-divided.

When transmitting a line-divided signal through a transmission path, various types of information are time-divided and an error-checkable code that represents a specific line or row is inserted for each line in order to align the horizontal phase. There is a known method for transmitting the information. When receiving a line-divided signal containing such a code, the code is detected for each line and lines for forming the same type of screen are selectively extracted.

Conventionally, in such a signal receiving device, if an error occurs in the code during transmission, it either discards all the information on that line, uses the information from the previous line, or uses the line where the error occurred as is. However, in these methods, when a reception error occurs due to the weakening of the received electric field or the incorporation of noise, the image quality deteriorates significantly.

In order to solve these problems, the present invention has the following features:
When an error is detected for each line, a correlation is made for each pixel with the information from the previous line, and when the information matches, that pixel information is regarded as correct information and used as the line signal. This improves image quality.

An embodiment of a signal receiving device according to the present invention is shown in FIG. FIG. 2 shows a pixel pattern for explaining the operation, and FIG. 3 shows the signal configuration of one line transmitted. The method for detecting line errors is to use the CRC inserted at the end of each line.
There are cases in which a code such as . Note that for the former as well, by adding a delay line of one horizontal period, it is possible to reduce image quality deterioration due to errors in a similar manner.

In FIG. 1, 1 is a signal input terminal, 2 is a clock input terminal, 3 is a shift register that takes in the received signal, 4 is a circuit that generates a predetermined pattern corresponding to the above code, and 5
6 is a first comparison circuit, 6 is a shift register for delaying one horizontal period, 7 is a second comparison circuit that compares a signal one horizontal period ago with a current signal, 8 is a signal switching circuit, and 9 is a signal switching circuit. Indicates the output terminal.

As shown in Fig. 3, the signal configuration of one transmitted line includes a code signal 13 for aligning the phase of one horizontal period, and a code signal 14 representing a time-divided program consisting of, for example, 4 bits. , a code signal 15 representing each program line, and a signal 16 representing an information pattern.

One line of signals as shown in FIG. 3 inputted from terminal 1 are sequentially stored in shift register 3 by a clock from terminal 2.

On the other hand, the pattern generating circuit 4 generates a code pattern including all codes representing programs and lines predetermined on the transmitting side.

When the code signal 14 representing a program and the code signal 15 representing a line of the program are read into the shift register 3, the comparison circuit 5 compares the output of the shift register 3 with the output of the pattern generation circuit 4, and a code error is detected. Ru. Here, the detection is performed by detecting whether the incoming code matches any one of the patterns generated by the pattern generation circuit 4, and if they do not match, it is regarded as a code error. The data passed through shift register 3 is further applied to shift register 6 and delayed by one horizontal period.

The signal delayed by one horizontal period and the signal not delayed are applied to a comparator circuit 7. The comparison circuit 7 is
According to the output of the comparison circuit 5, the switching circuit 8 is shifted to the current signal when there is no error in the code signal and when an error is detected in the code signal and there is a pixel correlation with information from one horizontal period ago. register 3
In addition, if an error is detected in the code signal and the pixel information before and after one horizontal period does not match according to the comparison result of the comparator circuit 7, the control circuit outputs the signal as no image signal. Control.

The switching circuit 8 includes a circuit that extracts line information that matches other program codes, and the output terminal 9 outputs information other than the desired program among the line information determined to have no code error. It is configured so that it does not.

Figure 2a shows a pixel pattern when the present invention is not used, where 10 indicates a signal correctly received one horizontal period ago, and 11 indicates a signal received with an error due to the incorporation of noise, etc. show.

In this device, when the upper and lower pixels are compared, if they match, that pixel is adopted, and if they do not match, it is output as an "O" signal (no signal), and the result is shown in Figure 2b. As shown, the signal shown at 11 is converted into the signal shown at 12 to improve the image quality. Although signals will be partially dropped due to errors, the image quality usually deteriorates less if the pixel signals are dropped than if they are increased.

Note that the present invention includes a correction bit and a parity bit in the program/line code, and has a function that allows the code to be corrected for small errors. It goes without saying that this type of signal receiving device can also be applied to image quality improvement when more errors occur than can be corrected.

As described above, according to the present invention, when an error is detected in a certain line, a correlation is made with the information of the previous line, and only the correlated pixel information is regarded as correct information, and the signal of that line is In addition, among the line information determined to be free of code errors, information other than the desired program does not occur.
A double check of code errors and program contents is performed, and even if the program is sent in time division, only the information of a predetermined program can be obtained, and the image quality can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a main part of an embodiment of a signal receiving device according to the present invention, FIG. 2 is a diagram showing a pixel pattern for explaining the operation of the embodiment, and FIG.
The figure is a diagram showing an example of the structure of a transmitted signal. 3...Shift register, 4...Pattern generation circuit, 5...Comparison circuit, 6...Shift register, 7
...Comparison circuit, 8...Switching circuit.

Claims (1)

[Claims] 1 A signal receiving device that receives video information transmitted in divided lines, in which one line receives a framing code signal for aligning the phase of one horizontal period, and a program code signal representing a time-divided program. , consists of a line code signal representing the line of each program and a signal representing an information pattern, which includes the program code signal and line code signal of the line signal captured by the signal capturing means, and the program code predetermined on the transmitting side. and the output of a pattern generating means that generates a code pattern including a line code, for each line, and when a line error is detected by the first comparing means,
a second comparison means for comparing, pixel by pixel, the output signal of the signal acquisition means with a signal of one line before the signal obtained by delaying the output signal of the signal acquisition means by one horizontal period by a delay means, and when there is no error in the code signal; When an error is detected in the code signal and there is a pixel correlation with information from one horizontal period ago, the current signal from the shift register is output as is, and an error is detected in the code signal.
and a switching circuit that outputs as no image signal when the picture element information before and after one horizontal period does not match according to the comparison result of the second comparing means, and the switching circuit outputs a line that matches another program code. A signal receiving device including a circuit for extracting information and configured so that information other than a desired program is not generated among line information determined to be free of code errors.