JPS6378685A - Method for forming television signal - Google Patents

Abstract

PURPOSE:To form a television signal having an aspect ratio with the shorter side at the top while said signal can be compatible with an NTSC system television by separating in terms of time base the low frequency component of an auxiliary image signal from the television signal having graphic information whose aspect ratio is larger than 4:3. CONSTITUTION:An image separation circuit 2 separates a main image signal made up of images in areas with aspect ratio 4:3 and an auxiliary image signal made up of images in areas shown by shadowed areas S from the television signal. According to the NTSC system the main image signal is encoded and supplied to a time base multiplex circuit 28. An LPF 24 and a subtractor 25 separate a low frequency component with high energy and a high frequency component with low energy from the auxiliary image signal. The both components are supplied to a time base compression circuit 26 and a time base expansion circuit 27. The low frequency component included in the auxiliary image signal subjected to time base compression is multiplexed in terms of time base, and supplied to a frequency base multiplex circuit 29.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a method for forming a television signal that is compatible with current television receivers and that enables television broadcasting with a horizontally expanded aspect ratio. It is related to.

Conventional technologyCurrent NTSC (National Television Network)
Approximately 25 years have passed since color television broadcasting using the onSystem system began in 1960. Meanwhile, 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 provided is changing from simple 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 (NHK) proposed a high-definition television system [for example, the literature special feature on high-definition television (Television Society Journal No. 36S,
No. 10, 1982)].

The contents include high definition with 1) 25 scanning lines, interlaced scanning, and 20 MIIz horizontal luminance bandwidth, as well as a screen aspect ratio of 5:3 from the perspective of visual engineering to create a sense of realism.
That is. This system has already been almost completed in closed systems, and with the start of satellite broadcasting, MU, which transmits high-definition television signals in the band of one satellite channel,
We have proposed the SE system [Reference, Tasuku Ninomiya et al., Satellite one-channel transmission system (MUSE) for high-definition television (electronic communication technology research report TB84-72, 1982)] and are conducting experiments.

On the other hand, the current NTSC system has specifications such as 525 scanning lines, interlaced scanning, a luminance horizontal bandwidth of 4.2 MHz, and an aspect ratio of 4:3.

As an image quality improvement method for the current NTSC system, a method of frequency multiplexing high-frequency information of an image (Public Patent Publication No. 12883/1986) has already been proposed as a method to improve horizontal resolution.
High-definition signal converters for television signals (see ``High Definition Signal Converter'') have been proposed. Further, as a method for increasing the resolution in the vertical direction, a method of performing ink-lace scanning-no-inclace scanning conversion has been proposed. In this way, the current NT
Although several practical methods have been proposed for increasing the definition of the SC method, no practical methods have been proposed regarding the aspect ratio, which greatly affects the sense of realism of images.

Problems to be Solved by the Invention As mentioned above, in the current NTSC system, the aspect ratio of images is 4:3, and when broadcasting services such as movies, both sides are It can only be transmitted by cutting or compressing it vertically so that the horizontal direction of the effective screen matches the movie.

Therefore, there have been problems such as a loss of realism and a reduction in screen area.

In view of the above problems, the present invention provides a method for forming a television signal having a horizontally elongated aspect ratio while maintaining compatibility with the current NTSC television format.

Means for Solving the Problems In order to solve the above problems, the present invention temporally separates the low frequency components of the sub-picture signal from the television signal having image information with an aspect ratio larger than 4:3. A television in which a high frequency component of the sub-picture signal is separated on a frequency axis, the sub-picture signal is obtained from a low-frequency component and a high-frequency component of the sub-picture signal, and the low-frequency component and high-frequency component of the sub-picture signal are separated. By decoding the signal using the NTSC method, a main image signal with an aspect ratio of 4:3 is obtained, and from the sub-image signal and the main image signal, an aspect ratio of 4:3 is obtained.
The present invention includes a method for forming a television signal that enables reproduction of images larger than 3.

Effect: The present invention uses the above-described method to reproduce realistic images whose aspect ratio is wider than the conventional NTSC system from a television signal containing image information whose aspect ratio is larger than 4:3. .

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

FIG. 1 is a block diagram showing a method of forming a television signal in an embodiment of the present invention. In Figure 1, 1
is an input terminal for a television input signal containing image information with an aspect ratio larger than 4:3, 2 is a frequency axis separation circuit,
3 is a time axis separation circuit, 4 is an NTSC decoder, 5 is a time axis expansion circuit, 6 is a time axis compression circuit, 7 is an adder, 8
Reference numeral 9 indicates an image synthesis circuit, and 9 an output terminal for a television signal formed by the method of this embodiment.

Before explaining this embodiment, let us first explain how to form a television input signal on the transmitting side that is input to the input terminal 1 in FIG. 1 and includes image information whose aspect ratio is larger than 4=3. This will be explained using FIG. 7 starting from the second leap.

FIG. 2 is an example of a block diagram showing the signal formation process on the transmitting side, where 21 is an input terminal for an image signal with an aspect ratio of 4 or greater than 3, 22 is an image separation circuit, and 23 is an NT
SC encoder, 24 is LPF (low pass filter), 25 is subtracter, 26 is time axis compression circuit, 27 is time axis expansion circuit, 28 is time axis multiplexing circuit, 29 is frequency axis multiplexing circuit, 30 is aspect It is an output terminal for a television signal containing image information with a ratio greater than 4:3.

A method of forming a television signal on the transmitting side using the configuration shown in FIG. 2 will be described below with reference to FIGS. 3, 4, 5, 6, and 7.

First, FIG. 3 shows an image whose aspect ratio is larger than 4:3 that is input manually to the input terminal 21 in FIG. The main image signal separated by the 1-image separation circuit 22 is separated into a main image signal consisting of an image in an area with a ratio of 483 and a sub-image signal consisting of an image in an area indicated by a diagonal line (■).
In the TSC encoder 23, the sub image signal separated in the 0 image separation circuit 22 is encoded in the NTSC format and is supplied to the time axis multiplexing circuit 28.
is supplied to the subtracter 25. This sub-image signal has a waveform as shown in FIG. 4 (al) on the time axis, and has a waveform as shown in FIG. 5 (al) on the frequency axis as a typical image signal characteristic.
As shown in FIG. 5, the sub-image signal is divided into the waveform of the low-frequency component with high energy (fb in FIG. 4) and the frequency spectrum of (1) in FIG. 5 by the LPF 24 and the subtracter 25. ) and relatively low-energy high-frequency components (waveform fdl in FIG. 4, frequency spectrum +dl in FIG. 5), and are supplied to a time-base compression circuit 26 and a time-base expansion circuit 27, respectively.

In the time axis compression circuit 26, the low frequency component shown in FIG. 4(b) is subjected to time axis compression as shown by TCI in the figure, and is supplied to the time axis multiplexing circuit 28. Furthermore, the frequency spectrum of the low frequency component is as shown in FIG. The signal is expanded and supplied to the frequency axis multiplexing circuit 29. At this time, the frequency spectrum of the high frequency component becomes as shown in FIG.
During the horizontal retrace period, vertical retrace period, etc. of the SC system signal, the low frequency components of the time-domain compressed sub-picture signal are time-domain multiplexed and supplied to the frequency-domain multiplexing circuit 29 . In the frequency axis multiplexing circuit 29, the high frequency components of the time axis expanded sub-image signal are modulated and multiplexed so as to be frequency interleaved and entered into the 301)z gap of the signal spectrum of the NTSC system shown in FIG. , is output from the output terminal 30.

As described above, according to this signal formation method on the transmitting side, the sub-image signal is separated into low frequency components and high frequency components by the LPF and the subtracter, and the low frequency components are sent to the narrow retrace period of the multiplexed region on the time axis. If the energy of the signal to be compressed, multiplexed, and frequency multiplexed is large, interference due to crosstalk to the brightness signal 2 signal will occur. By interleaving and multiplexing, the current NTSC
It is possible to transmit image information with an aspect ratio larger than 4:3 in a signal format that can be received even by standard television receivers.

Using the television signal formed by the method described above as an input signal, the method for forming the television signal shown in FIG. 1 will be described below.

In FIG. 1, the aforementioned television input signal inputted from the input terminal 1 is frequency-axis multiplexed in a frequency-axis separation circuit 2 in the form of frequency interleaving in the gap in the signal spectrum of the NTSC system shown in FIG. The high frequency components of the sub-image signal are separated by a comb filter etc.
The signal is supplied to the time axis compression circuit 6. Also, time axis separation circuit 3
In the NTSC system signal shown in FIG. 6, the low frequency components of the sub-image signal time-axis multiplexed during the horizontal retrace period, vertical retrace period, etc. are separated and supplied to the time-axis expansion circuit 5. The television signal in which the high frequency component and low frequency component of the sub-picture signal have been separated is decoded by the NTSC decoder 4 and supplied to the image synthesis circuit 8 as a main picture signal. In the time axis expansion circuit 5, the low frequency components of the sub-image signal which have been time axis compressed on the transmitting side (see Fig. 4 (waveform C1,
The frequency spectrum (frequency spectrum 101 in FIG. 5) is expanded on the time axis as shown in FIG. 4(b) and is supplied to the adder 7.

In the time axis compression circuit 6, high frequency components of the sub-image signal (waveform shown in tel in FIG. 4) are time axis expanded on the transmitting side.

The frequency spectrum shown in FIG. 5 (fe) is compressed on the time axis as shown in FIG.

The adder 7 adds the low frequency component (waveform of FIG. 4 (bl)) and high frequency component (waveform of fdl in FIG. 4) of the sub-image signal to reproduce the sub-image signal shown in FIG. 4 (5). , the image synthesizing circuit 8 supplies the image synthesizing circuit 8 with a main image signal consisting of an image with an aspect ratio of 4:3 and a sub-image signal consisting of an image of a wider area, and synthesizes the main image signal consisting of an image with an aspect ratio of 4:3. The image signal larger than 3 is reproduced and outputted from the output terminal 9.

By projecting the television signal output from the output terminal 9 using a picture tube or the like having an aspect ratio greater than 4:3, the original image shown in FIG. 3 can be reproduced.

As described above, according to this embodiment, by receiving an NTSC signal in which the low frequency component of the sub-image signal is multiplexed on the time axis and the high frequency component is multiplexed on the frequency axis, the aspect ratio is higher than that of the conventional NTSC system. Enables playback of large images.

Note that the LPF 24 in FIG. 2 in this embodiment has been described in one dimension, but if this is made into a two-dimensional LPF,
It is possible to separate high frequency components and low frequency components two-dimensionally. At this time, the time axis compression circuit 26 shown in FIG. 1 can perform two-dimensional compression, and therefore the time axis expansion circuit 5 shown in FIG. 1 can also perform two-dimensional time axis expansion.

Further, although the present embodiment does not distinguish between the brightness signal 1 and the sudden signal of the television signal, the television signal of the present invention can be formed according to each signal.

Effects of the Invention As described above, according to the present invention, when transmitting or servicing movies or programs with a sense of realism, images with an aspect ratio of 5:3, for example, are played back as they are on the receiver, so that the sense of realism is achieved. In addition, the intention of the program author can be fully conveyed, and the signal format is compatible with the conventional NTSC system, making it extremely effective industrially.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a method for forming a television signal in an embodiment of the present invention, FIG. 2 is a block diagram showing a method for forming a television signal on the transmission side inputted to the input terminal of FIG. 1, Figure 3 is a diagram of the composition of the image, Figure 4 (
a), middle school 1. (C1, (dl, tel are signal waveform diagrams showing the signal processing process in Figures 1 and 2, Figure 5 (a
l, (bl, (C1, fdl, (el is a frequency spectrum distribution diagram showing the signal processing process in Figures 1 and 2, Figure 6 is a diagram of the principle of time axis multiplexing, and Figure 7 is a diagram of the principle of frequency multiplexing. 2... Frequency separation circuit, 3... Time axis separation circuit, 4... NTSC system decoder, 5...
...Time axis expansion circuit, 6...Time axis compression circuit, 7...Adder, 8...Image synthesis circuit, 22... Image separation circuit, 23...
・NTSC encoder, 24...LPF. 25... Subtractor, 27... Time axis expansion circuit, 28... Time axis multiplex circuit, 29...
...Frequency axis multiplex circuit. Name of agent: Patent attorney Toshio Nakao Hakaichi Meiji
. ■ Figure 5 Figure 6 Figure 7

Claims (3)

[Claims] (1) From a television input signal containing image information with an aspect ratio larger than 4:3, the low frequency components of the sub-image signal are separated on the time axis, the high-frequency components of the sub-image signal are separated on the frequency axis, and the sub-image A method for forming a television signal, characterized in that the sub-image signal is obtained from a low frequency component and a high frequency component of the signal. (2) The sub-image signal is obtained after time-axis expansion of the low-frequency component of the sub-image signal and time-axis compression of the high-frequency component of the sub-image signal.
Method for forming a television signal as described in Section 1. (3) The sub-picture signal and the television input signal in which the low-frequency component and high-frequency component of the sub-picture signal are separated are
The television signal according to claim (2), characterized in that an image with an aspect ratio larger than 4:3 is reproduced by combining the main image signal obtained by decoding with the TSC method. How to form.