JPH01143594A - Formation of television signal - Google Patents

Abstract

PURPOSE:To reduce line flicker in the case of the reception by a TV receiver of the existing NTSC system by applying frequency axis multiplex of a vertical high frequency signal being the result of frequency-shifting a vertical high frequency component of a picture onto a TV signal. CONSTITUTION:A TV signal from a camera 101 is separated into a vertical low frequency component V-LPF and a vertical high frequency component V-HPF by a vertical filter 102. The V-LPF is encoded into the NTSC system TV signal by an NTSC system encoder 103 and the result is fed to a frequency axis multiplex circuit 104. On the other hand, the V-HPF becomes a vertical high frequency signal YVH by a horizontal filter 105. The signal YVH is frequency-shifted by a frequency shift circuit 106 and becomes a signal Y'VH and fed to a multiplex circuit 104, where the signal Y'VH is subjected to frequency axis multiplex onto the TV signal encoded into the NTSC system and the result is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for forming a television signal that is compatible with current television receivers and enables television broadcasting with improved vertical resolution. It is related to.

Prior TechnologyCurrent TechnologyNational Television System Committee (NTSC)
Approximately 27 years have passed since color television broadcasting using the Collm1ttee system began in 1961. Meanwhile, as the screens of television picture tubes have become larger, there has been a demand for higher-definition screens, and as the performance of television receivers has improved, various new television systems have been proposed. Furthermore, the content of the programs provided is changing from simply studio programs and relay programs to programs with higher quality and more realistic images, such as cinema-sized movie broadcasts.

Against this background, the Japan Broadcasting Corporation proposed a high-definition television system. (For example, Literature Special Feature on High Definition Television (Television Society Journal No. 36S, No. 10, 1)
(Refer to 1982)) The contents were as follows: 1) 25 scanning lines, interlaced scanning, 20 MIIz horizontal luminance bandwidth, high definition in the horizontal and vertical directions, and an aspect ratio of 5:3. - On the other hand, the current NTSC system has 525 scanning lines, interlaced scanning, horizontal brightness bandwidth of 4.2 MHz, and aspect ratio of 4:3.
It has various specifications.

As an image quality improvement method for the current NTSC system, it is already used in broadcasting as a method to improve horizontal resolution.
A method of frequency multiplexing horizontal high frequency information of an image (published patent
1983-12883 A high-definition signal converter for television signals has been proposed, and in the package system, etc.
This can be achieved by simply widening the luminance signal band (4.2MHz for broadcasting).

In order to improve the vertical resolution, the receiver side can perform interlaced scanning, progressive scanning, and scan conversion.
It is possible to improve the resolution that has been degraded by the l coefficient. However, in reality, in order to reduce line flicker in images reproduced by interlaced scanning on current television receivers, on the transmitting side, the vertical resolution of television cameras, etc. is reduced to some extent before transmission. Even if the scan conversion is performed, it is not expected that the vertical resolution will improve much.

Problems to be Solved by the Invention As mentioned above, the current NTSC system can improve the resolution in the horizontal direction, but due to the limitations of the number of scanning lines and the occurrence of line flicker, it is difficult to improve the resolution in the vertical direction. is difficult, and the horizontal and vertical resolutions of the reproduced image become unbalanced.

In view of the above-mentioned problems, the present invention has been developed to overcome the limit due to the number of scanning lines while maintaining compatibility with the current NTSC television system.
Moreover, some existing television receivers provide methods of forming television signals that hardly cause line flicker.

Means for Solving the Problems In order to solve the above problems, the method for forming a television signal of the present invention involves frequency-axis multiplexing a vertical high-frequency signal obtained by frequency-shifting the vertical high-frequency components of an image onto a television signal. This process is performed.

Operation The present invention uses the method described above to shift the frequency of the vertical high frequency component of an image to the current NTSC television signal, frequency axis multiplex it, and transmit it.
While maintaining compatibility with standard television receivers, it is possible to transmit information with a vertical resolution that exceeds the limit due to the number of scanning lines (so-called vertical sampling number), and to demodulate and display it on the receiver. shall be.

Furthermore, since the vertical high-frequency components are frequency-shifted and frequency-axis multiplexed, line flicker when received by a current NTSC television receiver can also be reduced.

Embodiment Hereinafter, a method for forming a television signal according to an embodiment of the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing a method of forming a television signal in a first embodiment of the present invention. In FIG. 1, 101 is a camera, 102 is a vertical filter, and 103 is an N
TSC encoder, 104 is a frequency axis multiplexing circuit, 1
05 is a horizontal filter, 106 is a frequency shift circuit, 10
7 is an output terminal.

Hereinafter, a method for forming the television signal shown in FIG. 1 will be explained using FIGS. 2 and 3. Note that FIG. 2 shows the characteristics of the filter in this embodiment, and FIG. 3 shows the frequency spectrum of the television signal.

Number of scanning lines: 525, interlaced scanning, field frequency: 60
The television signal output from the Hz camera 101 (
For example, the R, G, B signals) are separated into a vertical low frequency component V-LPF and a vertical high frequency component V-HPF in the vertical filter 102 according to the filter characteristics shown in FIG. It is supplied to a horizontal filter 105. NTSC encoder 10
3, the vertical low frequency component of the television signal ■-C
The PF is encoded into an NTSC television signal and supplied to the frequency axis multiplexing circuit 104. In the horizontal filter 105, the vertical high frequency component V-HPF is subjected to horizontal low frequency filtering with the characteristics shown in FIG. In the frequency shift circuit 106, as shown in the power spectrum diagram of FIG. In the 0-frequency multiplexing circuit 104, the NTSC encoder 103 outputs a television signal encoded in the NTSC system (as shown in FIGS. In the gap between the spectrum of the luminance signal Y and the chrominance signal C, the vertical high-frequency signal Y,...
' is output from the spectrum device 107.

As described above, according to this embodiment, the vertical high-frequency components are frequency-shifted and frequency-multiplexed onto the NTSC television signal, and transmitted, thereby eliminating line flicker when received by a conventional NTSC television signal. It becomes possible to form a television signal that can reproduce images with high vertical resolution without causing any distortion. Further, since the vertical high frequency component has small energy and is multiplexed with the conventional NTSC television signal in a frequency interleaved manner, there is little interference with the conventional NTSC television receiver.

A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a block diagram showing a method of forming a television signal in a second embodiment of the present invention.

In the figure, 401 is a double-speed progressive scanning camera, 402 is a spatio-temporal filter, 403 is a scan conversion circuit, and 404 is an NT
SC method encoder, 405 is a frequency axis multiplex circuit, 40
6 is a scan conversion circuit, 407 is a horizontal filter, 408 is a frequency shift circuit, and 409 is an output terminal.

Hereinafter, a method for forming the television signal shown in FIG. 4 will be explained using FIGS. 3 and 5. Note that FIG. 5 is a diagram showing the vertical-time frequency spectrum of the television signal in this embodiment.

Number of scanning lines: 525, sequential scanning, frame frequency: 60Hz
The television signal output from the double-speed scanning camera 401 has a frequency spectrum indicated by the - dotted chain line in the vertical-time frequency spectrum diagram of FIG. A filter with characteristics as shown by the solid line in the figure separates the vertical low frequency component V-LPF and the vertical high frequency component V-HPF,
They are supplied to scan conversion circuits 403 and 406, respectively. In the scan conversion circuit 403, the vertical low frequency component V-LP
The double-speed progressive scanning television signal consisting of F is converted to interlaced scanning, and the NTSC encoder 404
After being encoded into a TSC television signal,
The signal is supplied to a frequency axis multiplexing circuit 405. Vertical high frequency component V
- After the HPF is converted to interlaced scanning in the scan conversion circuit 406, the horizontal filter 40
7, the frequency is shifted in the frequency shift circuit 408 as shown in FIG.
05. In the frequency axis multiplexing circuit 405, as in the first embodiment, the vertical high frequency signal Y' do,
It is output from the output terminal 409.

As described above, according to this embodiment, the same effects as in the first embodiment can be achieved using a double-speed sequential scanning camera, and
Since a spatio-temporal filter is applied using a double-speed camera, it is possible to transmit and reproduce good television signals without aliasing distortion.

A third embodiment of the present invention will be described below with reference to the drawings.

FIG. 6 is a block diagram showing a method for forming a television signal in a third embodiment of the present invention.

In the figure, 601 is a double-speed interlaced scanning camera, 602 is a spatio-temporal filter I, 603 is a spatio-temporal filter n, and 604
is a scan conversion circuit, 605 is an NTSC encoder, 6
06 is a frequency axis multiplexing circuit, 607 is a frequency shift circuit 1
．． 608 is a vertical/horizontal filter, 609 is a scan conversion circuit, 610 is a frequency shift circuit (2), and 61) is an output terminal.

The method for forming the television signal shown in FIG. 6 will be described below with reference to FIGS. 3, 5, and 7. In addition, the seventh
The figure is a vertical-time frequency spectrum diagram showing the signal formation process of FIG. 6.

Number of scanning lines: 1050, interlaced scanning, field frequency: 60
The television signal output from the Hz double-speed interlaced scanning camera 601 has the vertical-temporal frequency spectrum shown in FIG. -CPF and the vertical high frequency component V-HPF shown in the same figure (fl), and are supplied to the space-time filter [603 and the frequency shift circuit 607. In the space-time filter The frequency spectrum of the television signal is limited to the band shown in FIG. 7 (cl) by a filter having the characteristics shown in FIG. , 525 scanning lines, converted to interlaced scanning, encoded into an NTSC television signal (consisting of the vertical-time frequency spectrum shown in FIG. 7+d), and then supplied to the frequency axis multiplexing circuit 606. Vertical high frequency component V
-HPF is the seventh
If) is converted to a lower frequency on the vertical axis as shown in gl, and is supplied to a vertical/horizontal filter 608.

In the vertical/horizontal filter 608, for the vertical high frequency component V-HPF converted to a low frequency on the vertical axis,
Figure 7 (525/4 (books) in the vertical direction as shown in hl)
The signal is further band-limited in the horizontal axis direction as shown in the first embodiment, and then output to the scan conversion circuit 609. In the scan conversion circuit 609, the above-mentioned vertical high frequency component V-CPF is converted into interlaced scanning with 525 scanning lines.
are supplied to the frequency shift circuit (2) as vertical high frequency signals Yv, I, and in the frequency shift circuit (2), as in the first embodiment, the vertical high frequency is applied to the gap in the spectrum of the current NTSC system, as shown in FIG. At this time, the vertical-time frequency spectrum is as shown in Fig. 7 (1) by frequency shifting the domain signal YVM.
As in the first embodiment, the 0-frequency axis multiplexing circuit 606 supplies the vertical high frequency signal Y'v,I to the frequency multiplexing circuit 606, in which the spectrum of the NTSC television signal is The vertical high frequency signal Y is inserted into the gap.
'v□ is frequency-multiplexed and the vertical-
time axis frequency spectrum) is output from the output terminal 61).

As described above, according to this embodiment, by using a double-speed interlaced scanning camera, frequency-shifting the vertical high-frequency components to low frequencies on the vertical axis and applying band limitation, the vertical resolution according to the NTSC system can be improved. It is possible to form a television signal with a resolution exceeding the limit of 525/2 (lines), and it is also possible to multiplex vertical high-frequency signals by interleaving them in the gaps in the frequency spectrum of the NTSC television signal. Therefore, even when the television signal of this embodiment is received by a conventional NTSC television receiver, almost no interference occurs.

In the above embodiments, if the vertical high-frequency signal including only the luminance signal is to be multiplexed onto the television signal, this can be done by combining the Y signal with a matrix circuit.

Further, the vertical filter in the first embodiment is realized by an inter-field filter according to the movement of the television image, thereby enabling better separation of vertical high-frequency components.

In addition, in the third embodiment, a double-speed interlaced scanning camera was used compared to the current NTSC camera; It is also possible to realize this by using a high quality television camera, in which case the scan conversion circuit 604 in FIG.
and 609 is a high-definition television to current NTSC television format conversion circuit.

Effects of the Invention As described above, the present invention maintains compatibility with current type television receivers by frequency-axis multiplexing a vertical high-frequency signal obtained by frequency-shifting the vertical high-frequency components of an image onto a television signal. To enable broadcasting using a television signal that can reproduce images with higher vertical resolution in signal form.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a method for forming a television signal in the first embodiment of the present invention, FIG. 2 is a characteristic diagram of each filter in FIG. 1, and FIG. 4 is a block diagram showing the method of forming a television signal in the second embodiment of the present invention, FIG. 5 is a characteristic diagram of the spatio-temporal filter in FIG. 4, and FIG. FIG. 7 is a block diagram showing a method of forming a television signal in the third embodiment. FIG. 7 is a vertical-time frequency spectrum diagram showing the signal forming process in FIG. 101...Camera, 102...Vertical filter, 103...NTSC encoder, 104...Frequency axis multiplex circuit, 105...
... Horizontal filter, 106 ... Frequency shift circuit, 401 ... Double speed scanning camera, 402
...... Space-time filter, 403 ... Scan conversion circuit, 404 ... NTSC encoder, 405 ... Frequency axis multiplex circuit, 406 ...
...Scan conversion circuit, 40? ...Horizontal filter, 408 frequency shift circuit, 601 ... Double-speed interlaced scanning camera, 602 ... Time-space filter ■,
603... Spatio-temporal filter I [, 604...
...Scan conversion circuit, 605...NTSC encoder, 606...Frequency axis multiplex circuit, 6
07... Frequency shift circuit I, 608...
...Vertical/horizontal filter, 609...Scan conversion circuit, 610...Frequency shift circuit ■. Name of agent: Patent attorney Toshio Nakao (1 person)
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Claims (2)

[Claims] (1) A method for forming a television signal, comprising frequency-shifting a vertical high-frequency signal consisting of vertical high-frequency components of an image to a frequency that is frequency interleaved with a television signal, and frequency-axis multiplexing the signal on the television signal. . (2) Formation of a television signal according to claim (1), wherein the vertical high-frequency signal is a signal in which the vertical high-frequency component is frequency-shifted on the vertical axis and band-limited. Method.