JPH0817481B2 - Television signal decoding device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television signal decoding device, and in particular, a current television system has an aspect ratio (horizontal to vertical ratio) of 4:
3, the present invention relates to a television signal decoding device that reproduces a television signal that is suitable for transmitting scene information having a larger aspect ratio and that is compatible with the current television system. .

Conventional Technology Japan's current NTSC (National Television System Committee)
mittee)] method for color television broadcasting in Showa 35
More than 25 years have passed since it started in the year. Meanwhile, various new television systems have been proposed in response to the demand for high-definition screens and the improvement in performance of television receivers. In addition, the contents of the programs to be provided themselves are changing from simple studio programs and relay programs to programs with higher image quality and more realistic images, such as cinema-sized movie broadcasts.

Against this background, the Japan Broadcasting Corporation (NHK) has proposed a high-definition television system. (For example, literature special issue on high-definition television (Journal of the Television Society, Vol. 36, Vol.
No. 10, 1982, see)) The content is 1125 scanning lines,
2: 1 interlace scanning, luminance signal horizontal bandwidth of 20 MHz, and high definition, while the aspect ratio (horizontal to vertical ratio of the screen) is set to 5: 3 from the viewpoint of visual engineering such as presence. . This system has been almost completed in the closed system, and the MUSE system that transmits high-definition television in the band of one satellite channel with the start of satellite broadcasting (Reference, Yuichi Ninomiya et al., Satellite 1-channel transmission system (MUSE) of high-definition television) (Technical report of IEICE IE84-72, 1984)) and is conducting experiments.

On the other hand, the current broadcasting has various specifications such as 525 scanning lines, 2: 1 interlaced scanning, luminance signal horizontal bandwidth 4.2MHz, and aspect ratio 4: 3. (For example, bibliographic technology, bibliography, color television, edited by Japan Broadcasting Corporation, Japan Broadcast Publishing Association, 19
In addition, when offering a movie as the above program, cut the screen size at both ends so that the aspect ratio of the current TV receiver is 4: 3, or provide an invalid screen at the top and bottom of the screen. The aspect ratio of the effective screen is transmitted so that it becomes the value of the movie.

Problems to be Solved by the Invention As described above, when transmitting and servicing a movie program or a realistic screen in the current broadcast, the screen may be partially cut or the screen area may be reduced. There was a problem that the intention of was not fully communicated. Also, simply
If a signal with an aspect ratio larger than 4: 3 is simply transmitted, a normal receiver cannot receive it. When the number of scanning lines and the frame frequency are the same as those of the current broadcasting, in order to obtain the same horizontal resolution, the aspect ratio m: 3 (m is a real number of 4 or more) requires a video band that is m / 4 times the current video band. However, from the viewpoint of effective use of radio resources, it is impossible to extend the transmission band.

Therefore, an apparatus has been invented that transmits an image having an aspect ratio of 4: 3 or more, that is, an image having a wide aspect ratio within the band of the current television broadcasting. This will be explained below. Generally, in order to obtain the same horizontal resolution when the number of scanning lines and the frame frequency are the same, the aspect ratio is 5:
In the 3 system, the bandwidth required for transmission is 1.25 times that of the 4: 3 aspect ratio. Therefore, the increased bandwidth is accumulated in the first and third quadrants on the "time-vertical" two-dimensional frequency, or by a method such as being piled up in the high range of the color signal, while maintaining the horizontal resolution while maintaining the bandwidth of the current television system. It is intended to transmit video with a wide aspect ratio inside. (See Japanese Patent Laid-Open No. 60-213185) However, if an image with an aspect ratio of 5: 3 is transmitted as it is by such a conventional technique, it will be converted into a vertically long image when received by a current television receiver. However, there is a drawback that compatibility with the current television receiver cannot be maintained. In the case of a moving image, the increased bandwidth cannot be multiplexed in the first and third quadrants on the "time-vertical" two-dimensional frequency due to the crosstalk, so that the horizontal resolution is lowered.

The present invention has been made in view of the above points, and an object of the present invention is to provide a television signal decoding device that is compatible with the current television system and that reproduces a television signal having a horizontally long aspect ratio. To do.

Means for Solving the Problems In order to solve the above problems, a television signal decoding device of the present invention provides a frequency axis multiplexed signal separating means for separating a frequency axis multiplexed signal and a time axis multiplexed signal. It comprises a time axis multiplex signal separating means for separating and a time axis compressing means for time axis compressing the luminance signal and the color signal obtained from the composite video signal.

Effect The present invention has the above-described configuration, which allows the current television broadcast to be received by the time axis compression without any trouble, and also provides a horizontally wide screen with a wide aspect ratio by performing synchronous detection, time axis compression, time axis extension, or the like. Can be obtained.

Embodiment A television signal decoding device according to an embodiment of the present invention will be described below with reference to the drawings. Fig. 2 (a)
2B shows an example of a display screen of a current television, and FIG. 2B shows a composite video signal in one scanning line period near the center of the screen. Since the aspect ratio is 4: 3, a part of the left and right circles out of the three circles may be missing as in the display example of FIG. FIG. 3 (a) shows an aspect ratio larger than that of the current one, for example,
An example of the display screen in the case of 5: 3 is shown in FIG. 3 (b), which shows a video signal in one scanning line period near the center of the screen, and FIG. FIG. 7 shows a composite video signal in which the sync signal and the color burst signal are added by rewriting the video signal shown in FIG. 3B so as to be equal to b). The aspect ratio is not limited to 5: 3. If the aspect ratio is increased as shown in FIG. 3 (a), more video information can be obtained than in the screen shown in FIG. 2 (a). Here, in the current television receiver, even when receiving the video signal of the aspect ratio 5: 3, it is possible to receive the image without trouble as compared with the conventional one, that is, in order to maintain compatibility, the current television receiver The time-axis expansion is applied to the television signal in the period displayed on the screen. This can be seen by comparing FIG. 2 (b) and FIG. 3 (c), and when the current television receiver receives the signal of FIG. 3 (c), the original image is a circle. Nevertheless, since it becomes a vertically long ellipse, it is necessary to extend the signal of FIG. 3 (c) on the time axis. That is, when the original image is captured with a horizontally long aspect ratio m: 3 (m is a real number of 4 or more), the image signal corresponding to the portion displayed on the screen of the current television receiver is multiplied by m / 4. It suffices to extend the time axis. Furthermore, the remaining signal portion (hereinafter referred to as side signal) to obtain screen information with an aspect ratio of m: 3
Decides to send low frequency components by time axis multiplexing and high frequency components by frequency multiplexing. In a CCD camera or the like that does not require a horizontal blanking period as much as the image pickup tube, it is not always necessary to extend the image pickup signal corresponding to the portion displayed on the screen of the current television receiver on the time axis. That is, because the horizontal blanking period becomes shorter, there is a margin in the time axis direction.

FIG. 4 is a spectrum diagram showing a frequency axis multiplexing method for side signals on the transmission side 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, the case where the lower sideband of the image carrier P ₁ is the vestigial sideband is shown. FIG. 4 (b) shows a side signal, which has the same frequency as the video carrier P ₁ and a phase difference of 90 °.
P ₂ is vestigial sideband amplitude modulated to remove carrier P ₂ . Note that the carrier wave P ₂ is removed during part or all of the blanking period, and if the carrier wave P ₂ is not removed during the video signal period, the DC component of the side signal can also be multiplexed. FIG. 4 (c) is a signal obtained by multiplexing the signal shown in FIG. 4 (b) with the television signal shown in FIG. 4 (a).

Next, a processing method of the television signal decoding device in the embodiment of the present invention will be explained. The signal in the video intermediate frequency band, which is the output of the tuner, is band-limited by a filter that removes orthogonal distortion as shown in FIG. When this is displayed as a vector, it becomes as shown in FIG. Since the video baseband signal becomes almost double-sideband by the filter, if the upper and lower sidebands are Bertrel a _U and Bertrel a _L , their combined vector becomes a ₁ and only the component orthogonal to vector I ₂ . Also, considering the carrier I ₂ as the center, the multiplexed signal has vestigial sidebands, so the upper and lower sidebands become vector b _U and vector b _L , and when decomposed into orthogonal vectors, vector b ₁ ,
It becomes the vector b ₂ . That is, when the coherent detection is performed on the carrier I ₂ , orthogonal distortion due to the vector a ₁ and vector b ₁ components does not occur, and only the multiple signal component can be demodulated.

FIG. 1 is a block diagram of a television signal decoding device according to an embodiment of the present invention. In FIG. 1, 1 is an antenna, 2 is a tuner, 3 is a video intermediate frequency filter, 4 is a video detector, 5 is a carrier recovery circuit, 6 is a filter, 7 is a phase shifter, 8 is a multiple signal detector, 10, 17 is a YC separation circuit, 12,
13, 14 and 16 are time axis compression circuits corresponding to time axis expansion on the sending side, 11 and 18 are I and Q demodulation circuits, 15 is a signal switching circuit, 9 is a signal separation circuit, 19 is a matrix circuit, and 20 is R, G, B signal output terminals, 21 is a reference signal extraction circuit, 22 and 24 are luminance / chromaticity adjustment circuits, 23 is a time axis expansion circuit compatible with time axis compression on the sending side, and 25 is a time axis adjustment circuit. Is. The signal transmitted from the transmitting side is received by the antenna 1, frequency-converted into an intermediate frequency band by the tuner 2, and band-limited by the video intermediate frequency filter 3. Although the antenna is illustrated, the transmission path is not limited to the wireless system, and may be a wired system. The band-limited signal is supplied to the video detector 4 and the carrier wave reproduction circuit 5. The carrier wave reproducing circuit 5 reproduces the carrier wave I ₁ for synchronous detection. The band-limited signal is synchronously detected by the video detector 4 on the carrier I ₁ . The output of the video detector 4 is a video baseband signal. Also, the output of the tuner 2 is the
Bandwidth is limited as shown in FIG. The carrier I ₁ obtained from carrier recovery circuit 5 with the phase shifter 7 with the carrier I ₂ obtained by 90 degree phase shift, the multiplexed signal band-limited signal detector 8
In the synchronous detection. The phase shift direction of the carrier wave I ₂ is the same as that of the sending side. The detection output becomes a multiplexed signal. The video baseband signal is separated by the YC separation circuit 10 into a Y signal and a C signal. The signal separating circuit 9 separates the synchronizing signal, the color burst signal, the identification signal for distinguishing the wide television signal from the television signal of the current broadcast and the reference signal from the video baseband signal. The reference signal is, for example, a white signal level, a black signal level,
It is a standard reference signal that can correct the amplitude, phase, etc. of the color signal, and is for matching them with the side signal. An example is shown in FIG. Brightness / Chromaticity adjustment circuit
Do at 24. The Y signal output from the luminance / chromaticity adjustment circuit 24 is time-axis compressed by the time-axis compression circuit 12 to become a Y ₁ signal. Further, the C signal which is the output of the luminance / chromaticity adjusting circuit 24 is separated into the I signal and the Q signal by the I and Q demodulating circuit 11. The I signal is time-axis compressed by the time-axis compression circuit 13.
It becomes the I ₁ signal. The Q signal is time-axis compressed by the time-axis compression circuit 14 to become a Q ₁ signal. Multiplexed signal is time axis compression circuit 16
The time axis compression is performed by and the output is input to the YC separation circuit 17. The signal separated into the Y signal and the C signal by the YC separation circuit 17 is input to the luminance / chromaticity adjustment circuit 22. On the other hand, of the multiplexed signals output from the multiplexed signal detector 8, the reference signal previously superimposed on the transmitting side is the reference signal extracting circuit.
Extract at 21. The reference signal is a reference reference signal capable of correcting, for example, the white signal level, the black signal level, the amplitude and phase of the color signal on the receiving side as described above, and makes the video baseband signal and the side signal coincide with each other. It is for. The side signal is corrected by the luminance / chromaticity adjustment circuit 22. The Y ₃ signal output from the luminance / chromaticity adjustment circuit 22 is input to the time axis adjustment circuit 25. The C signal output from the luminance / chromaticity adjustment circuit 22 is output by the I and Q demodulation circuit 18 to I ₃
The signal and the Q ₃ signal are separated and input to the time axis adjustment circuit 25. The time-axis adjusting circuit 25 performs a process reverse to the time-axis adjusting on the transmitting side, and the transmission and reception are integrated so that the regular time relationship is maintained. Of the video baseband signals output from the video detector 4, the time-axis expansion circuit 23 expands the time-axis-compressed signal on the transmission side as shown in FIG. The time-axis expansion can be performed by changing the write and read clocks to the memory, as in the time-axis compression. The output of the time axis expansion circuit 23 is added to the Y ₃ signal in the time axis adjustment circuit 25. Time axis adjustment circuit 25
The output of the signal switching circuit is as Y ₂ signal / I ₂ signal / Q ₂ signal.
Is input to Wherein _{Y 1, I 1, Q 1} , Y 2, I 2, Q 2 signal, the signal switching circuit 15, first, an aspect ratio of 4: For the portion corresponding to the third current television receiver screen, Y ₁ , I ₁ ,
Select the Q ₁ signal. Since these are time-axis-compressed, for the remaining period of one horizontal scanning period, a blanking signal or the like is generated and selected inside the signal switching circuit 15 for the current broadcasting. When receiving the wide television signal, Y ₂ , I ₂ , and Q ₂ signals are selected. The signal switching control is performed by an identification signal from the signal separation circuit 9 for identifying the wide television signal and the television signal of the current broadcast. The output of the signal switching circuit 15 becomes R, G, B signals by the matrix circuit 19. The time axis compression circuits 12, 13, 14 and 16 enable the current television broadcasting to be received without any trouble, and by compressing the time axis expanded portion of a television signal having a horizontally long aspect ratio, It is for restoring a television signal. That is, as can be seen by comparing FIG. 2 (b) and FIG. 3 (c), in order to receive the current broadcast image without knowing its aspect ratio, the current television signal is time-axis compressed. I need to do it. The compression ratio is determined by the aspect ratio. However, it is not always necessary to compress the time axis for a display such as a liquid crystal display that does not require a blanking period as much as a CRT. When receiving a current television signal, a screen with an aspect ratio of 4: 3 is displayed near the center, and the remaining area of the receiver screen with a landscape aspect ratio is darkened by blanking or the like. It suffices to perform processing such as. The identification signal may be superimposed on the vertical blanking period, for example, and may be substituted with the reference signal.

FIG. 8 shows a signal switching circuit 15 according to an embodiment of the present invention.
It is a block diagram of. 51 and 52 are selectors, 53 is a blanking signal generation circuit, and 54 is an identification signal input terminal. If it is determined by the identification signal that the image does not have a wide aspect ratio, the selectors 51 and 52 select the Y ₁ , I ₁ , and Q ₁ signals during the period corresponding to the screen with the aspect ratio of 4: 3, and the blocks other than the above periods. The blanking signal from the ranking signal generating circuit 53 is selected. If it is determined that the video has a wide aspect ratio based on the identification signal, the selectors 51 and 52 may select the Y ₂ , I ₂ , and Q ₂ signals.

EFFECTS OF THE INVENTION As is apparent from the above description, the present invention comprises means for synchronously detecting a television signal, means for time axis compression, and means for time axis expansion, transmitting scene information with a larger aspect ratio than the current one, In addition, by reproducing a television signal having compatibility that it can be received even by the current television without any trouble, it is possible to obtain a screen having an aspect ratio wider than the current one. Further, the current television signal can be received without any trouble.

[Brief description of drawings]

FIG. 1 is a block diagram of a television signal decoding device according to an embodiment of the present invention, FIG. 2 (a) is an explanatory diagram showing an example of a display screen of a current television, and FIG. 2 (b) is An explanatory view showing a composite video signal in one scanning line period near the center of the screen, FIG. 3 (a) shows an aspect ratio of, for example, 5: 3.
FIG. 3 (b) is an explanatory view showing a video signal in one scanning line period near the center of the screen, and FIG. 3 (c) is a time axis scale. Figure 2 (b)
3B is an explanatory view showing a composite video signal in which the video signal shown in FIG. 3B is rewritten so that a synchronizing signal and a color burst signal are added, and FIG. 4A shows the residual in the current television system. FIG. 4B is a spectrum diagram of a side-band amplitude-modulated television signal. FIG. 4B is a spectrum diagram in which a signal (side signal) different from the signal shown in FIG. FIG. 4 (c) is a spectrum diagram in which the signal shown in FIG. 4 (b) is multiplexed with the signal of FIG. 4 (a),
5 (a) and 5 (b) are multiple signals (side signals).
A spectrum diagram and a vector diagram at the time of demodulation, FIG. 6 is a waveform diagram showing a reference signal, FIG. 7 is an explanatory diagram showing time axis compression, time axis expansion, and time axis multiplex position, and FIG. 8 is FIG. 3 is a circuit configuration diagram of an example of a signal switching circuit 15 in FIG. 7 ... Phase shifter, 3 ... Image intermediate frequency filter, 6 ... Filter, 12,13,14,16 ... Time axis compression circuit, 23 ... Time axis expansion circuit, 22,24 ... Luminance / color Degree adjustment circuit, 21 …… Reference signal sampling circuit, 25 …… Time axis adjustment circuit, 15 …… Signal switching circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideshi Inoue 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Hideyo Kamihata, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A part corresponding to an aspect ratio of 4: 3 of an electric signal obtained by capturing an original image having an aspect ratio larger than 4: 3 is time-axis expanded to form a composite video signal, and the rest of the electric signal is obtained. The high frequency component of the signal obtained from the part of Fig. 1 is time-axis expanded and frequency-axis multiplexed, and the low-frequency component is time-axis compressed and the frequency-axis multiplexed signal is separated from the time-axis multiplexed television signal. A television signal including signal separating means, time axis multiplexed signal separating means for separating time axis multiplexed signals, and time axis compression means for time axis compressing luminance signals and chrominance signals obtained from the composite video signal. Decoding device. 2. A frequency axis multiplex signal separating means, a filter for removing quadrature distortion, a means for synchronously detecting a carrier wave having the same frequency as the image carrier wave and a phase difference of 90 °, and the time axis compression of the synchronously detected signal. The television signal decoding device according to claim 1, further comprising: 3. The television signal decoding apparatus according to claim 1, wherein the time axis multiplex signal separating means comprises means for expanding the time axis and means for adjusting the time axis.