JPH01168183A - Television signal synthesizer - Google Patents

Abstract

PURPOSE:To reproduce a picture having a wide aspect ratio by an exclusive receiver and to receive the picture by the existing television receiver by generat ing a television signal applying multiplex transmission of other information while keeping compatibility with the existing television broadcast. CONSTITUTION:A luminance signal Y obtained from a signal picked up by a camera with a larger aspect ratio than the existing ratio is given to a time axis expansion circuit 24, an LPF 22 and an HPF 23, separated into a low frequency component with a high energy and a high frequency component with a comparatively lower energy, and fed to a time axis compression circuit 25 and a time axis expansion circuit 26 respectively. Then the television signal during the period displayed on the screen of the existing television receiver is subject to time axis expansion and the remaining signal component is subject to time axis multiples for lower frequency component and subject to frequency multiplex for a high frequency component. The chrominance signals I, Q are processed similarly. Thus, the picture having a wide aspect ratio is obtained by the exclusive receiver and the picture is also received by the existing tele vision receiver.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a television signal synthesis device that is capable of transmitting a video signal with an aspect ratio different from that of the current television system while maintaining compatibility with the current television system. It is related to.

Conventional TechnologyCurrent NTSCC National Television in Japan
System Committee (National Te1e
-vision System Commftee
)) More than 25 years have passed since color television broadcasting began in 1960. In the meantime, various new television systems have been proposed in response to demands for high-definition screens and improvements in the performance of television receivers. Furthermore, the content of the programs being serviced is changing from simple studio programs and broadcast programs to programs that include higher quality images with a sense of realism, such as the broadcast of cinema-sized movies.

Against this background, the Japan Broadcasting Corporation (NHK) proposed a high-definition television system. (For example, Literature Special Feature on High Definition Television (Television Society Journal Vol. 36,
No. 10, 1982) The contents are as follows: Number of scanning lines: 1) 25, 2:1 interlaced scanning, luminance signal horizontal bandwidth: 20
MHz, and high definition, and from the viewpoint of visual engineering such as immersion, the aspect ratio (ratio of horizontal to vertical screen) was increased to 5:
3.

This system has already been almost completed in the closed system, and with the start of satellite broadcasting, the MUSE system (References, Tasuku Ninomiya et al.,
High-definition television satellite x1 channel transmission system (MUSE)
(IEICE technical research report IE84-72.198
4th year)) and are currently conducting experiments.

On the other hand, current broadcasting uses 525 scanning lines, 2:1 interlaced scanning,
Luminance signal horizontal bandwidth 4.2 MI (Z, aspect ratio 4:
It has various specifications of 3. (For example, see Literature and Broadcasting Technology Bibook, Color Television, published by Japan Broadcasting Corporation, Japan Broadcasting Publishing Association, 1961.) When providing a movie as the above program, the screen size should be adjusted to the aspect ratio of the current television receiver. Either the ends are cut off to make it 4:3, or invalid screens are placed at the top and bottom of the screen, and the aspect ratio of the valid screen is sent out to match the movie value.

Problems to be Solved by the Invention As mentioned above, when transmitting and servicing movie programs and immersive screens in current broadcasting, some parts of the screen are cut off, or the screen area is small, so production There was a problem in that the intention of the person was not sufficiently conveyed.Also, if a signal with an aspect ratio larger than 4:3 was simply transmitted, it would not be able to be received by a normal receiver.The number of scanning lines, When the frame frequency is the same as that of current broadcasting, in order to obtain the same horizontal resolution, an aspect ratio of m:3 (m is a real number of 4 or more) requires a video bandwidth m/4 times that of the current broadcasting.

However, from the point of view of effective use of radio wave resources, the transmission band cannot be expanded unnecessarily.

Therefore, a device has been invented that transmits a video having an aspect ratio of 4:3 or more, that is, a wide aspect ratio video. This will be explained below. In general, in order to obtain the same horizontal resolution when the number of scanning lines and frame frequency are the same, a system with an aspect ratio of 5:3 must use an aspect ratio of 4.
:The bandwidth required for transmission is 1.25 times that of 3. By stacking the increased bandwidth in the first and third quadrants of the "time-vertical" two-dimensional frequency, or in the high range of the color signal, the bandwidth of the current television system can be improved while maintaining the horizontal resolution. The idea is to transmit wide-aspect ratio video within the network.

(Refer to Japanese Unexamined Patent Publication No. 60-213185.) However, if video with an aspect ratio of 5:3 is transmitted using this conventional technology, when received by current television receivers, the video will be vertically elongated. The disadvantage is that it cannot maintain compatibility with current television receivers.

Furthermore, in the case of moving images, the increased bandwidth cannot be multiplexed into the first and third quadrants on the "time-vertical" two-dimensional frequency due to crosstalk, resulting in a decrease in horizontal resolution.

The present invention has been made in view of the above, and an object of the present invention is to provide a television signal synthesis device that is compatible with the current television system and that generates a television signal having a more horizontally elongated aspect ratio. do.

Means for Solving the Problems In order to solve the above-mentioned problems, the television signal synthesis device of the present invention has an aspect ratio of 4:3 among electrical signals obtained by capturing an original image having an aspect ratio larger than 4:3.
: A means for extending the time axis of the portion corresponding to 3 and modulating the residual sideband amplitude as a composite video signal, and adding a carrier wave having the same frequency as the video carrier wave but a different phase to the television signal subjected to the residual sideband amplitude modulation. is subjected to double-sideband amplitude modulation or single-sideband amplitude modulation using a composite signal obtained by time-expanding the high frequency component obtained from the remaining part of the electrical signal, and the frequency characteristics up to the video intermediate frequency amplification stage of the receiver are The method uses a means for multiplexing signals band-limited by Nyquist filters having opposite frequency characteristics, and a composite signal obtained by compressing the low frequency components obtained from the remaining part of the electrical signal in the time domain, at least for a part of the video signal period. It is equipped with means for time-axis multiplexing a part of the retrace period.

The present invention uses the method described above to generate a television signal that can multiplex transmit different information while maintaining compatibility with current television broadcasting. Not only that, but also multiplexed information can be obtained, that is, images with a wide aspect ratio can be obtained, and furthermore, even with current television receivers, it can be received as conventional television broadcast images with almost no problems. can.

Embodiment Hereinafter, a television signal synthesis apparatus according to an embodiment of the present invention will be described with reference to the drawings. Figure 2 (al is
An example of a display screen of a current television is shown in FIG. 2(b), which shows a composite video signal for one scanning line period near the center of the screen. Since the aspect ratio is 4=3, the second
As shown in the display example in Figure (a), part of the left and right circles among the three circles may be missing. Figure 3 (8) shows an example of a display screen with a larger aspect ratio than the current one, for example 5:3 (bl is the video signal for one scanning line period near the center of the screen). , in Figure 3 (C), the scale of the time axis is the same as the second opening).
This shows a composite video signal obtained by rewriting the video signal in Figure fb) and adding a synchronization signal and a color burst signal. Note that the aspect ratio is not limited to 5:3. Figure 3 [
If the aspect ratio is increased as shown in a), the image shown in Figure 2 (a)
You can get more video information than a screen like 1. Here, even when the current television receiver receives a video signal with an aspect ratio of 5:3, it is possible to receive the image without any problems compared to conventional television receivers.In other words, in order to maintain compatibility, the current television receiver The time axis is expanded on the television signal during the period displayed on the screen. This can be seen by comparing Figure 2 (fb) and Figure 3 (C), and when the signal in Figure 3 (C1) is received by a current television receiver, even though the original image is a circle. Regardless, it becomes a vertically elongated ellipse, so it is necessary to expand the time axis of the signal shown in Figure 3 (C).In other words, the original image is created with a horizontally elongated aspect ratio of m:3 (m is a real number of 4 or more) than before. When capturing an image of In order to obtain the remaining signal, the low frequency components are sent by time axis multiplexing, and the high frequency components are sent by frequency multiplexing.

Note that in COD cameras and the like that do not require an image pickup tube during the horizontal retrace period, it is not necessarily necessary to extend the time axis of the image signal corresponding to the portion displayed on the screen of a current television receiver. In other words, this is because the horizontal retrace period is shortened, and there is a margin in the time axis direction.

FIG. 4 is a spectrum diagram showing a frequency multiplexing method of a television signal synthesizer according to an embodiment of the present invention. FIG. 4(a) is a spectrum diagram of a television signal subjected to vestigial sideband amplitude modulation in the current television system. Here, a case is shown in which the lower sideband of the video carrier wave P1 is a residual sideband. Figure 4(b) is Figure 4(a)
This is a multiplexed signal different from the television signal shown in , which is a carrier wave P2 having the same frequency as the video carrier wave P1 but having a phase difference of 90 degrees, and which has been subjected to residual sideband amplitude modulation so as to remove the carrier wave P2. The signal in Figure 4(b) is converted to Figure 4(a).
FIG. 4(C) shows the result multiplexed with the television signal, and becomes the television signal synthesized according to the present invention.

Note that the band of the signal modulated by the multiplexed signal is from a frequency 4.25 MHz lower than the carrier wave P2 to a frequency 1.25 MHz higher, but is not limited to this.

Next, a television signal processing method on the receiving side will be explained. In the following, we will take the case of terrestrial broadcasting as an example. Figure 5 (a
) is a block diagram of a current television receiver that performs video synchronous detection. 241 is an antenna, 242
243 is a tuner, 243 is a video intermediate frequency filter, 244 is a video detector, 245 is a carrier regeneration circuit, and 246 is a video baseband signal output terminal. A signal sent from the transmitting side is received by an antenna 241, frequency-converted to an intermediate frequency band by a tuner 242, and then passed through a video intermediate frequency filter 2.
Bandwidth is limited by 43. The band-limited signal is supplied to a video detector 244 and a carrier recovery circuit 245. The carrier wave regeneration circuit 245 regenerates the carrier wave 1) for synchronous detection.

The band-limited signal is a carrier wave 1. video detector 244
The signal is detected and becomes a video baseband signal. Here, the frequency characteristics of the video intermediate frequency filter 243 will be described. The frequency characteristics are shown in Figure 5 (bl).In other words, the amplitude is attenuated by 6 dB at the video carrier wave 1, resulting in a Nyquist filter characteristic that has an amplitude characteristic that is almost oddly symmetrical with respect to the video carrier wave 1. There is. On the other hand, as shown in Fig. 4(b), if the multiplexed signal is band-limited by a filter having a frequency characteristic opposite to that of the video intermediate frequency filter of the receiver, then as shown in Fig. 5 (the shaded part of bl) The multiplexed signal component almost has both sidebands.If this is expressed as a vector, it will look like Figure 5 (C).Here, ■1 is the video carrier of the video baseband signal, and ■2 is the carrier of the multiplexed signal, which is I+. They are carrier waves with the same frequency but a phase difference of 90°.If the video baseband signal is considered around carrier wave 1, it becomes a residual sideband, so the upper and lower sidebands become vector au and vector aL, which are orthogonal vectors. When decomposed, they become vector al and vector a2.Also, since the multiplexed signal has almost both sidebands, if the upper and lower sidebands are vector bu and vector bL, their combined vector becomes b2, which is orthogonal to vector 1). Only the ingredients that That is, carrier wave 1. When synchronous detection is performed with
, vector b2 components do not cause orthogonal distortion, and in principle, multiple signals do not interfere with current television receivers that perform video synchronous detection.

FIG. 1+a+ is a block diagram of a television signal synthesis device according to an embodiment of the present invention. In Figure 1 (al), 1 is a signal generator, 2 is a main signal input terminal, 3 is an amplitude modulator, 4 is a first filter, 5 is an adder, 6 is an oscillator, 7
8 is a phase shifter, 8 is a multiplexed signal input terminal, 9 is a modulator, 10 is a second filter, 1) is a composite signal output terminal, 12 is a transmitter, 13 is an antenna, and 14 is a multiplexed signal superimposition circuit. A signal generator 1 generates a main signal and a multiplex signal. The main signal is input from the main signal input terminal 2 to the multiplex signal superimposition circuit 14 . The multiplexed signal is input from the multiplexed signal input terminal 8 to the multiplexed signal superimposition circuit 14 . The carrier wave P obtained from the oscillator 6 is amplitude-modulated by the amplitude modulator 3 using the main signal input to the multiplex signal superimposition circuit 14 . The obtained amplitude modulated wave is band-limited by the first filter 4 to form a residual sideband, and then added to the adder 5. A carrier wave P obtained from an oscillator 6 is phase-shifted by a phase shifter 7 and an adder 5 so that the carrier waves are orthogonal to each other, and a carrier wave P2 is obtained. Using the multiplexed signal input to the multiplex signal superimposition circuit 14, the carrier wave P2 is subjected to double-sideband amplitude modulation or single-sideband amplitude modulation with carrier cancellation, at least during the retrace period, by the modulator 9. Note that the phase shift direction of the phase shifter 7 may be fixed, but may be changed, for example, at least every horizontal scanning period, every -field, and every -frame. The output of the modulator 9 is band-limited by a second filter 10 and then applied to the adder 5. The output of adder 5 becomes a composite signal. The composite signal is sent out by a transmitter 12 and an antenna 13. Here the second
It is assumed that the frequency characteristic of the filter 10 is as shown in FIG. 1 filter 4 may be used as a composite signal.

FIG. 1 (bl is a block diagram showing an example of the internal configuration of the signal generator 1 in FIG. 1 (al). 21 is a block diagram showing an example of the internal configuration of the signal generator 1 in FIG. 24.26.33.35.41.4 input terminal; 30 is an input terminal for the color signal Q obtained from the signal; 38 is an input terminal for the color signal Q obtained from the signal; 24.26.33.35.41.4
3 is a time axis expansion circuit, 25.34.42 is a time axis compression circuit, 27.36.44 is a switch, 22.31.39 is L
PF (low pass filter), 23.32.40 is HPF
(high pass filter), 28.46 is adder, 37.45
29 is a main signal output terminal, and 47 is a multiplexed signal output terminal. The signal corresponding to the part displayed on the screen of current television receivers is the first signal, and the other signal, for example, the part on both sides or one side of the screen, is the second signal.
Signal. For example, the luminance signal Y, which is obtained from a signal captured by a camera with a larger aspect ratio than the current one, through a well-known matrix circuit, etc.
and is input to the HPF 23. When an original image is conventionally captured with a horizontally elongated aspect ratio of m:3 (m is a real number of 4 or more), the first signal corresponding to the part displayed on the screen of a current television receiver is, for example, As shown in the figure, time axis expansion circuits 24, 33, and 41 expand the time axis by a factor of m/4. As mentioned above, in COD cameras and other cameras whose horizontal retrace period does not require an image pickup tube, it is not necessary to extend the time axis of the signal corresponding to the part displayed on the screen of current television receivers. . On the time axis, the luminance signal has a waveform as shown in FIG.
As shown in FIG. 8(a), a spectrum distribution in which high frequency components have low energy is shown. The luminance signal of the second signal corresponding to both sides or one side of the screen is transmitted through the LPF 22 and the HP
By F23, low frequency components with high energy (Fig. 7 (
The waveform of the waveform of The signal is supplied to an axis compression circuit 25 and a time axis expansion circuit 26. In the time axis compression circuit 25, as shown in FIG.
As shown in the same figure (C), the low frequency component shown in bl is NT
The signal is time-axis compressed into a frequency spectrum that falls below the band that can be transmitted by the SC method, and is supplied to the switch 27, where it is time-axis multiplexed. As shown in FIG. 6, the time-base compression circuit 25 compresses the time-base signal at least during a part of the electron beam overscanning period of the receiver or a part of the front porch of the horizontal retrace period. The time shall be adjusted so that the time axis is multiplexed. Generally, a receiver overscans the electron beam by about 8% of the effective screen.

Therefore, for example, if the time is adjusted so that the time-axis compressed signal is time-axis multiplexed during a period corresponding to 2% of the time and 2% of the effective front porch screen, the time-axis Multiplexed signals do not cause interference. Time axis adjustment can be achieved by, for example, delaying the signal using a memory or the like. Time axis expansion and time axis compression can be performed, for example, by changing the writing and reading clocks to the memory. In the time axis expansion circuit 26,
As shown in FIG. 7(e), the high frequency component shown in FIG. 7(d) is time-axis expanded so that the band is equal to or less than the frequency-axis multiplexable band. The signal band-compressed by the time axis expansion circuit 26 is input to an adder 46.

Color signal I and color signal Q are similarly processed. For example, a color signal I and a color signal Q obtained from a signal captured by a camera with a larger aspect ratio than the current one through a well-known matrix circuit, etc. are obtained by a time axis expansion circuit 33.41, an LPF 31.39
and HPF32.40, respectively. When an original image is conventionally captured with a horizontal aspect ratio of m:3 (m is a real number of 4 or more), the first signal corresponding to the part displayed on the screen of a current television receiver is converted into a luminance signal Y. As in the case of , the time axis is expanded by m/4 times using the time axis expansion circuits 33 and 41. The second color signal ■ and the color signal Q corresponding to the parts on both sides or one side of the screen are each passed through the LPF 31.
．． 39 and HPF 32.40, the signal is separated into low frequency components with high energy and high frequency components with relatively low energy, and these are supplied to a time axis compression circuit 34.42 and a time axis expansion circuit 35.43, respectively. The time axis compression rate, time axis expansion rate, and time axis adjustment are the same as in the case of the luminance signal.

The time-domain compressed signals are each supplied to a switch 36.44, where they are time-domain multiplexed with the output of the time-domain expansion circuit 33.41. The outputs of the switches 36 and 44 are orthogonally modulated in the balanced modulation circuit 37, and added to the output of the switch 27 in the adder 28. The output of adder 28 becomes the main signal. The outputs of the time axis expansion circuits 35 and 43 are orthogonally modulated by the balanced modulation circuit 45, and added to the output of the time axis expansion circuit 26 by the adder 46. The output of adder 46 becomes a multiplexed signal.

If HPF32.40 is changed to LPF, LPF31.39
, time axis compression circuit 34, 42, and switch 36, 44 may be omitted.

Although retrace period signals such as synchronization signals and burst signals are omitted, reference signals, identification signals, and the like may be multiplexed in the retrace period. The reference signal refers to a standard reference signal that allows the receiving side to correct, for example, the white signal level, black signal level, amplitude and phase of the color signal, and a control signal that controls the reproduced carrier. Further, the identification signal is a signal for identifying, for example, the composite signal and a currently broadcast television signal.

Since the band of the time-axis expanded signal is expanded by time-axis compression on the receiving side, the resolution does not decrease even if the aspect ratio increases. Among the second signals that correspond to information on both sides or one side of the screen that does not fit on a screen with an aspect ratio of 4:3, the frequency-multiplexed signal has a spectrum that overlaps with that of current televisions.
In current receivers, most of the interference is canceled by synchronous detection using the video carrier wave, so interference caused by the frequency multiplexed signal hardly occurs. In addition, the receiver for multiplexed signal demodulation can extract the main signal without orthogonal distortion, similar to current receivers, and by performing synchronous detection using filtered and phase-controlled video carrier waves, the aspect ratio is 4:3.
Frequency multiplexed signals corresponding to information on both sides or one side that do not fit on the screen can also be extracted without orthogonal distortion.

Further, time-axis multiplexed signals can also be reproduced by processing such as time-axis expansion. That is, it is possible to reproduce the original image captured on the transmitting side and having an aspect ratio of 4:3 or more.

Effects of the Invention As is clear from the above explanation, by generating a television signal that can multiplex transmit different information while maintaining compatibility with current television broadcasting, a dedicated receiver can replace conventional television. Not only broadcast images but also multiplexed information can be obtained. That is, it is possible to play back video having a wide aspect ratio. Furthermore, there is almost no interference when received by a current television receiver, ensuring compatibility with current television receivers. In other words, since different information can be multiplexed and transmitted, it is very effective from the standpoint of effective use of radio wave resources.

[Brief explanation of the drawing]

FIG. 1 (al is a block diagram of a television signal synthesis device in an embodiment of the present invention, FIG.
FIG. 2 is a block diagram showing an example of the internal configuration of the signal generator of 1 (al is a front view showing an example of the display screen of a current television; FIG. 2 is a block diagram showing an example of the internal configuration of the signal generator of FIG. 3(a) is a front view of an example of a display screen when the aspect ratio is set to, for example, 5:3; FIG. 3(a) is a waveform diagram showing a composite video signal of A waveform diagram showing the video signal during the line period, Figure 3 tc+, is a synchronization signal and color by rewriting the video signal shown in Figure 3 (b) so that the time axis scale is the same as that in Figure 2 (b). FIG. 4(a) is a waveform diagram showing a composite video signal to which a burst signal has been added; FIG. FIG. 4(e) is a spectrum diagram in which the signal shown in FIG. 4(a) is modulated and band-limited by a signal different from the signal shown in FIG.
Spectrum diagram multiplexed with the signal in Figure + a), Figure 5 (a)
is a block diagram of a current television receiver that performs video synchronous detection, and Figures 5(b) and 5(C) are waveforms shown in spectral diagrams during synchronous detection of current television receivers. It is a diagram. 24, 26.33.35.41.42... Time axis expansion circuit, 25.34.42... Time axis compression circuit, 37.45... Balanced modulation circuit ,7...
... Phase shifter, 4... First filter, lO...
...Second filter. Name of agent Patent attorney Toshio Nakao Haka 1 (Figure tb) Yumi-5 Figure 6 Video signal period Mizuko soul return period Figure 7 Amplitude

Claims (3)

[Claims] (1) Time axis expansion means for time axis expansion of a portion corresponding to an aspect ratio of 4:3 of an electrical signal obtained by capturing an original image having an aspect ratio larger than 4:3, and a composite video signal is generated. a composite video signal generating means; a means for separating a signal obtained from the remaining part of the electrical signal into a high frequency component and a low frequency component; a means for converting the first composite signal into a second composite signal, a frequency axis multiplexing means for frequency axis multiplexing the first composite signal, a means for compressing the low frequency component in the time axis and then converting the first composite signal into a second composite signal; A television signal synthesis device comprising time axis multiplexing means for time axis multiplexing composite signals. (2) The frequency axis multiplexing means includes a carrier wave generation means, a first amplitude modulation means for amplitude modulating the carrier wave output from the carrier wave generation means with the residual sideband signal, and a shifter for controlling the phase of the carrier wave. and second amplitude modulation means for performing double-sideband amplitude modulation or single-sideband amplitude modulation of the output carrier of the phase-shifting means with the first composite signal in at least a portion of the retrace period with carrier cancellation; The television signal synthesis apparatus according to claim 1, further comprising a filter having a Nyquist characteristic that band-limits the output of the second amplitude modulation means. (3) The time axis multiplexing means includes means for multiplexing the second composite signal into at least a part of the video signal period or a part of the retrace period. The television signal synthesis device described in Section 1.