JPH047638B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is capable of transmitting high-definition color signals of 1050 scanning lines by line-sequentially transmitting color difference signals of high-definition color television signals through two transmission paths. For both a color television receiver and a standard color television receiver with 525 scanning lines (hereinafter referred to as standard color television in the description of the present invention),
The present invention relates to a high-definition color television transmission method that can satisfy compatibility in the number of scanning lines of received images.

Conventional configurations and their problems In recent years, high-definition color television systems that have about twice the number of scanning lines as the current standard color television system have been proposed in Japan and around the world, and there is a trend toward practical use. It is in.

In realizing a high-definition color television system, the amount of information to be transmitted increases, so a transmission path with a wide frequency band is required, but it satisfies the compatibility of signal transmission with the current standard color television system. In order to support future signal transmission using broadcasting satellites, high-definition color television will be transmitted using a signal transmission path with a signal frequency band comparable to that used for standard color television signal transmission. A method of transmitting signals becomes necessary. For this purpose, for example, the high-definition color television transmission device and the transmitter described in Japanese Patent Application Laid-open No. 58-133090, which separates the high-frequency component and low-frequency component of a wideband luminance signal and transmits them via two transmission paths, are proposed. There is also an example of a method proposed for transmitting broadband high-definition color television signals via two transmission paths in order to satisfy compatibility with standard color television systems. be.

A conventional example related to the present invention will be described below with reference to the drawings.

FIG. 1 shows the signal form of a color difference signal in a conventional high-definition color television transmission method, and a represents the input signal form to a signal converter on the transmitting side. b is a signal form of the output signal of the signal conversion device on the transmitting side that is transmitted via the first transmission path, and c is a signal form that is similarly transmitted via the second transmission path. b and c are also input signals to the signal converter on the receiving side. d is the output signal form of the signal converter on the receiving side.

A method of transmitting high-definition color television signals via two transmission paths will be described below. Note that only the color difference signal of the color television signal will be explained here. The processing of the luminance signal can be carried out in accordance with the processing of the corresponding color difference signal, so a description thereof will be omitted.

In FIG. 1, the scanning line group shown by the solid line is 1
The scanning line group indicated by the broken line constitutes a field different from the field constituted by the scanning line group indicated by the solid line. The first color difference signal component R _i and the second color difference signal component B _i (i=4n, 4n+1, 4n+2, 4n+
3: n=0, 1, 2...) are included.

In order to transmit these signal groups via two transmission paths, the signals are converted as follows. Color difference signals R _4o and R _4o included in the 4nth scanning line indicated by a
The color difference signal R 4o ₊₁ included in the 4n+1 scanning line on the same color axis as The signal transmitted on the 2N scanning line of the transmission path is 3/4R _4o + 1/4R _4o+1 .

On the other hand, the 2N scanning line of the second transmission path indicated by c transmits a signal R _4o+1 that is used auxiliary to reproduce the original signal on the receiving side.

Similarly, a color difference signal B _4o+2 of a color axis different from the above included in the 4n+2 scanning line indicated by a,
B _4o+2 processes the color difference signal B 4o+3 included in the 4n+3 scanning line on the same color axis, and processes the color difference signal B _4o+3 included in the 4n+3 scanning line on the same color axis, and processes the signal 3/3 on the 2N+1 scanning line of the first transmission path indicated by b.
4B _4o+2 +1/4B _4o+3 is the signal B _4o+3 that is transmitted on the 2N+1 scanning line of the second transmission path indicated by c.

Thereafter, the above processing is similarly repeated for two adjacent scanning lines of the signal group indicated by a. At this time, the number of scanning lines of the signal groups indicated by b and c becomes half the number of scanning lines of the signal group indicated by a, and the signal frequency band can be compressed to 1/2. Furthermore, the line sequential nature of the color difference signals is maintained because the transmitted signals are different for each scanning line.

Here, by using only the signal transmitted via the first transmission path indicated by b, the number of scanning lines is
It is possible to receive standard color television with 525 lines, and is compatible with high-definition color television with 1050 lines.

The signal groups b and c transmitted through the two transmission paths are converted into a signal group that can be received by a high-definition color television receiver having 1050 scanning lines as follows. Signal 3/4R _4o + 1/4R _4o+1 on the 2nd N scan line denoted by b to the 2nd N scan line denoted by c
R _4o is obtained by canceling and normalizing the signal R _4o+1 on the scan line. The obtained signal R _4o and the cth
R _4o on the 4nth scan line, denoted by d, so that the signal R _4o+1 on the 2N scan line is temporally aligned with the original signal.
R 4o+ _{1 is placed on the 4n+} 1 scan line. Similarly b
Signal 3/4B _4o+2 on the 2N+1 scan line shown by
+1/4B _4o+3 and the signal B _4o+3 on the 2N+1 scan line, denoted by c, are processed, B _4o+2 on the 4n+2 scan line, denoted by d, and B _4o+3 on the 4n+3 scan line, denoted by d. Deploy.

Thereafter, the above processing is repeated for the signals between the corresponding scanning lines b and c.

In the above signal processing, calculations are performed to transmit color difference signals via two transmission paths, but before the calculation processing, signal conversion on the transmitting side is performed by reducing the number of scanning lines by half within the transmission path and transmitting. Extend the time axis by two times. This means that the signal frequency band is reduced and signal transmission in a narrow band becomes possible. Regarding signal conversion on the receiving side, after arithmetic processing, the time axis is compressed to 1/2 to reproduce a wideband signal.

However, in the above conversion method, in the output signal d corresponding to the high-definition television system,
When the two color difference signals are transmitted, the line sequential nature of the signals is destroyed, resulting in distortion of the color difference signal components in the vertical direction, resulting in a problem in that faithful reproduction cannot be performed. Also, although it is possible to replace this signal so that it becomes line sequential, this involves replacing the position information and it is not possible to match the original signal temporally, so it is still necessary to perform faithful reproduction. The problem was that it was not possible.

Purpose of the invention The present invention solves the above-mentioned conventional problems.
By transmitting the color difference signals included in high-definition color television signals line-sequentially through two transmission paths, the number of scanning lines of the received image can be reduced in a standard color television receiver with 525 scanning lines. Even in high-definition color television receivers with 1050 scanning lines, the signal obtained by restoring the color difference signals transmitted through two transmission paths satisfies line sequentiality. The object of the present invention is to provide a high-definition color television transmission method.

Structure of the Invention When transmitting the high-definition color television signal of the present invention, two scanning lines located one scanning line apart from each other in units of four scanning lines from the beginning of each field are used. Among color difference signals, this method transmits the sum and difference between signals on the same color axis through different transmission paths, and uses signals transmitted through both the first transmission path and the second transmission path. Therefore, it is possible to obtain a high-definition color television signal that satisfies the line sequentiality of color difference signals, and in addition, by using only the signal transmitted via the first transmission path, a standard color television signal can be obtained. It is characterized by the compatibility that can be obtained.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 shows the signal format of the color difference signal in the high-definition color television transmission method of the present invention, and the signal formats a, b, c, and d are the signal formats of the conventional example shown in FIG. It corresponds to

A method of transmitting high-definition color television signals via two transmission paths will be described below. Incidentally, for the same reason as stated when explaining the conventional example, a description of the processing of the luminance signal will be omitted.

In FIG. 2, the scanning line group shown by the solid line is 1
The scanning line group indicated by the broken line constitutes a field different from the field constituted by the scanning line group indicated by the solid line. The first color difference signal component R _i and the second color difference signal component B _i (i=4n, 4n+1, 4n+2, 4n+
3: n=0, 1, 2...) are included.

In order to transmit these signal groups via two transmission paths, the signals are converted as follows. Color difference signals R _4o and R _4o included in the 4nth scanning line indicated by a
The color difference signal R 4o ₊₂ included in the 4n+2 scanning line on the same color axis as The signal transmitted on the 2N scanning line of the transmission path is 7/8R _4o + 1/8R _4o+2 .

On the other hand, the 2N scanning line of the second transmission line indicated by c is a signal 7/8R _4o − which is obtained by multiplying the same color difference signals as above by the same coefficients and then subtracting them.
Set it to 1/8R _4o+2 .

Similarly, the color difference signal B 4o ₊₁ of a color axis different from the above included in the 4n+1 scanning line indicated by a
B _4o+1 processes the color difference signal B 4o+3 included in the 4n+3 scanning line on the same color axis, and processes the color difference signal B _4o+3 included in the 4n+3 scanning line on the same color axis, and converts the signal 5/
8B _4o+1 +3/8B _4o+3 is the signal 5/8B _4o+1 -3/ on the 2N+1 scanning line of the second transmission line, indicated by c.
8B _4o+3 is transmitted.

Thereafter, the above-described processing is repeated for each of the four scanning lines of the signal group indicated by a. At this time, the number of scanning lines of the signal groups indicated by b and c becomes half the number of scanning lines of the signal group indicated by a, and the signal frequency band can be compressed to 1/2. Furthermore, the line sequential nature of the color difference signals is maintained because the transmitted signals are different for each scanning line.

Here, by using only the signal transmitted via the first transmission path indicated by b, the number of scanning lines is
It is possible to receive standard color television with 525 lines, and is compatible with high-definition color television with 1050 lines.

The signal groups b and c transmitted through the two transmission paths are converted into a signal group that can be received by a high-definition color television receiver having 1050 scanning lines as follows. 2nd N denoted by b and c respectively
R _4o is obtained by adding and normalizing the signal components 7/8R _4o +1/8R _4o+2 and 7/8R _4o -1/8R _4o+2 on the scanning line. Also the above signal 7/8R _4o +
Subtract 7/8R _4o −1/8R 4o ₊₂ from 1/8R _4o+2 ,
By normalizing we get R _4o+2 . R _4o is placed on the 4nth scanning line indicated by d, and R _{4o +2} is placed on the 4nth+2 scanning line so that the obtained signals R 4o and R _4o+2 match the original signal. Similarly, the second N+ denoted by b
The signal on the 1st scan line 5/8R _4o+1 3/8B _4o+3 and the signal on the 2N+1 scan line indicated by c 5/8B _4o+1 −
3/8B _4o+3 is processed and B _4o+1 is placed on the 4n+1st scan line, indicated by d, and B 4o+ ₃ is placed on the 4n+3rd scan line.

Thereafter, the above processing is repeated for the signals between the corresponding scanning lines b and c.

In the above signal processing, addition and subtraction are performed to transmit color difference signals via two transmission paths, but for signal conversion on the transmitting side before arithmetic processing, the number of scanning lines is halved in the transmission path and transmitted. Therefore, the time axis is expanded twice. This leads to a reduction in the signal frequency band, making it possible to transmit signals in a narrow band. Regarding signal conversion on the receiving side, after arithmetic processing, the time axis is compressed to 1/2 to reproduce a wideband signal.

As described above, according to this embodiment, when performing color difference signal conversion on the transmitting side, 4
A method of transmitting the sum and difference between the signals on the same color axis among two color difference signals on scanning lines arranged one scanning line apart from each other using different transmission paths. Therefore, the line sequentiality of the color difference signals transmitted can be satisfied even in the high-definition color television signal group shown in FIG. 2d, and this has a great practical effect. In this example, the scanning line of the standard color television system is
525 lines and 1050 lines for high-definition color television system, but regardless of these scanning lines, the number of scanning lines for standard color television system and high-definition color television system is This is possible if the ratio is approximately 1:2. Also,
Although various configurations are possible for the apparatus that specifically implements the transmission method of the present invention, as an example, FIG. 3 shows a signal conversion apparatus on the transmitting side, and FIG. 4 shows a signal converting apparatus on the receiving side.

The configuration of the signal converter on the transmitting side and the flow of signals will be explained with reference to FIG. 1 is an input terminal for the luminance signal Y, 2 is an input terminal for the first color difference signal R _i , and 3 is an input terminal for the second color difference signal B _i . R _i from the input terminal 2 and B _i from the input terminal 3 enter the R/B selection circuit 4 at the same time, and the color difference signal for calculation is selected. The form of the signal input to this R/B selection circuit 4 is shown in FIG. 2a. The first color difference signal R _i selected by the R/B selection circuit is input to the time axis expansion circuit 5 , and the second color difference signal B _i is input to the time axis expansion circuit 6 . These double the time axis and reduce the frequency band by half. Luminance signal Y
The signal also passes through the time axis expansion circuit 7, and its frequency is reduced by half. Each time-axis expanded color difference signal is branched into a signal that passes through delay circuits 8 and 9 that delays by two horizontal scanning periods and a signal that does not pass, and addition and subtraction are performed in arithmetic circuits 11 and 12. The first color difference component and the second color difference component of the color difference signals subjected to addition and subtraction are alternately selected by selection circuits 14 and 15, respectively, in color difference line sequential order.

The form of the signal transmitted through the signal line 16 is shown in FIG. 2b, and the form of the signal transmitted through the signal line 17 is shown in FIG. 2c. Thereafter, after being multiplexed with the luminance signal in multiplexing circuits 18 and 19, the addition signal is output from the output terminal 20 for transmission via the first transmission line, and the subtraction signal is output from the output terminal 20 for transmission via the second transmission line. Output terminal 2
Output from 1.

Next, the configuration of the signal converter on the receiving side and the flow of signals will be explained with reference to FIG. 22 is an input terminal for the signal transmitted via the first transmission path;
is an input terminal for the signal transmitted via the second transmission path. Signals input from each terminal are first separated into a luminance signal and a color difference signal by Y/C separation circuits 24 and 25. The sum signal and difference signal transmitted through each transmission path of these signals are decomposed into individual signals by arithmetic circuits 26 and 27, respectively. Here, delay circuits 28 and 29 perform a delay of two horizontal scanning periods to achieve alignment on the time axis.
are provided, respectively, and selection circuits 30 and 31 alternately select signals that pass through delay circuits 28 and 29 and signals that do not. The signals selected by selection circuits 30 and 31 are input to time axis compression circuits 32 and 33, respectively. These compress the time axis to 1/2 and double the frequency band. The form of the signal transmitted on the signal line 34 is shown in FIG. 2d. The time-axis compressed luminance signal Y is output from the output terminal 35, and the color difference signal is output from the R/B separation circuit 3.
6, the signal is separated into a first color difference signal R _i and a second color difference signal B _i , and outputted from an output terminal 37 and an output terminal 38, respectively.

Effects of the Invention The high-definition color television transmission system of the present invention calculates color difference signals on scanning lines arranged one scanning line apart from each other in units of four scanning lines from the beginning of each field. , 1st
In addition to standard color television reception that uses only the signal via the transmission line, it also supports high-definition color television reception that uses two signals via both transmission lines, including the second transmission line. It is possible to reproduce a line-sequential color difference signal even in reception at a computer, and it has a great practical effect because it can prevent undesired deterioration of color resolution in the vertical direction.

[Brief explanation of drawings]

FIG. 1 is a signal form diagram of a color difference signal in a conventional high-definition color television transmission method, and FIG. 2 is a signal form diagram of a color difference signal in a high-definition color television transmission method according to an embodiment of the present invention. FIG. 3 is a block diagram showing an example of a signal conversion device on the transmitting side, and FIG. 4 is a block diagram showing an example of a signal converting device on the receiving side. 5, 6, 7... Time axis expansion circuit, 8, 9, 1
0, 28, 29...Delay circuit, 11, 12, 13
...Transmitting side arithmetic circuit, 26, 27... Receiving side arithmetic circuit, 32, 33... Time axis compression circuit.

Claims (1)

[Claims] 1 When transmitting a high-definition color television signal, the signals of the 4nth scanning line, the 4n+2 scanning line, the 4n+1 scanning line, and the 4n+3rd scanning line are transmitted in units of four scanning lines from the beginning of each field. By adding the 2nd N scan line and the 2nd N+
converting the signal into one scanning line signal and transmitting at least the first color difference signal component and the second color difference signal component alternately via the first transmission path in the 2Nth scanning line and the 2N+1th scanning line, respectively; 4n scan line and 4nth
+2 scan line, and 4n+1 scan line and 4n+3 scan line
By subtracting the signals of the scanning lines, respectively, the signals are converted into signals of the 2N scanning line and the 2N+1 scanning line, and at least the first color difference signal component and the second color difference signal component are converted to the signals of the 2N scanning line and the 2N+1 scanning line, respectively. A high-definition color television transmission method characterized in that the high-definition color television is transmitted alternately through a second transmission path.