JPH06319123A - Television signal transmission method, transmitter and receiver - Google Patents

Abstract

PURPOSE:To provide the television signal transmission method, the television signal transmitter and receiver in which a defect exerted on an existing receiver is relieved in the wide EDTV system. CONSTITUTION:An orthogonal transformation matrix circuit 30 at a transmitter side is used to apply arithmetic operation processing by linear transformation between plural scanning lines of a reinforcement signal separated from an original signal thereby spreading a signal component localized with a large amplitude into a block through the use of orthogonal transformation and suppressing the level and smoothing the distribution. The reinforcement signal subject to transformation processing is synthesized with a video signal of a main screen by a letter box processing circuit 31 and the result is sent. A separator circuit 32 separates the signal comprising the synthesis of the video signal and the reinforcement signal of the main screen into the video signal and the reinforcement signal of the main screen. The separated reinforcement signal is converted into the reinforcement signal before transformation processing by an inverse matrix circuit 33. Noise of a non-picture portion is reduced through the processing as above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide EDTV system compatible with current television broadcasting, and more particularly, to a television signal transmitting method, a transmitting device and a television signal transmitting method capable of reducing adverse effects on a current receiver. Relating to a receiving device.

[0002]

2. Description of the Related Art NTSC, the current television broadcast
The transmission method has an aspect ratio of 4: 3, but as the next-generation television transmission method, the aspect ratio is 16: 9.
Wide aspect-based wide EDTV broadcasting is being considered. In wide EDTV broadcasting, the current N
In order to obtain an image having higher image quality than that of TSC broadcasting, it has been considered to transmit a reinforcement signal together with a video signal.

FIG. 4 is a conceptual diagram of a letterbox format which is a transmission format of wide EDTV broadcasting. The letterbox format of wide EDTV broadcasting is a method for maintaining compatibility with current broadcasting, and the video signal of the main screen is 36
It is transmitted by 0 interlaced scanning, and the reinforcement signal is transmitted by 120 scanning lines to the upper and lower parts (non-image part) of the main screen. Since the original signal of wide EDTV broadcasting is a progressive scanning (non-interlaced) signal of 480 lines, a component that cannot be expressed by interlaced scanning of 360 lines on the main screen is transmitted as a reinforcement signal.

In a wide EDTV receiver having a dedicated decoder, it is possible to obtain a high-quality image of 480 progressive scans by the video signal of the main screen transmitted in the letterbox format and the reinforcing signals at the top and bottom of the screen. In addition, even in the current image receiver that does not have a dedicated decoder (receiving device), 360 interlaced scanning images can be obtained by the video signal of the main screen transmitted in the letterbox format.

FIG. 5 shows an example of an encoder (transmission device) for a wide EDTV signal. 4 → 3 conversion circuit 10
Then, the input original signals of 480 progressive scanning (in the figure,
480p) is separated into a vertical low frequency component having a vertical frequency of 0 to 360 TVL and a vertical high frequency component (VH) having a vertical frequency of 360 to 480 TVL. Further, the vertical low-frequency component is converted into 360 sequential scanning signals (360p),
It is output to the p → i conversion circuit 11. Further, the vertical high frequency component is output to the selection circuit 12.

The p → i conversion circuit 11 separates a sequential scanning signal having a lattice arrangement as shown in FIG. 6 into a scanning line represented by a circle and a scanning line represented by a cross. At this time, the scanning line represented by x is filtered by the vertical high-pass filter having the characteristic shown in FIG. The scanning lines represented by ◯ are output as video signals of 360 interlaced scans (360i) of the main screen. Further, the scanning line represented by x is output to the selection circuit 12 as a line difference component (LD). The selection circuit 12 receives VH and L according to an arbitrary selection signal.
D is selected and output as a reinforcement signal. By the above processing, the video signal of the main screen and the reinforcement signals at the top and bottom of the screen transmitted in the letterbox format can be obtained.

FIG. 8 shows an example of a decoder for wide EDTV signals. The transmitted reinforcement signals at the top and bottom of the screen are discriminated by the discriminating circuit 20 as VH or LD according to an arbitrary discriminating signal. The reinforcement signal determined to be VH is output to the 3 → 4 conversion circuit 21, and the reinforcement signal determined to be LD is i.
→ Output to the p conversion circuit 22.

The i → p conversion circuit 22 converts the transmitted video signals of 360 interlaced scans of the main screen into 360 progressive scans by motion adaptive processing. The motion adaptive processing here switches between inter-field interpolation when stationary, interpolation by LD transmitted as an upper and lower line sum and a reinforcement signal when moving, and processing depending on screen motion. The 3 → 4 conversion circuit 21 converts the 360 sequential scanning signals output from the i → p conversion circuit 22 into 480 sequential scanning signals, and transmits the VH transmitted as a reinforcement signal.
Add. By the above processing, the video signal of 480 sequential scanning of the original signal can be restored.

[0009]

In wide EDTV broadcasting, as described above, the current T having an aspect ratio of 4: 3 is used.
The V screen is divided into a letterbox type main screen and upper and lower non-picture areas for use in transmitting television signals. When this broadcast is received by a current receiver that does not have a dedicated decoder, an image of this format is displayed on the display screen.
At that time, there is no problem because the image on the main screen is the same as that of the current broadcast, but the images in the upper and lower non-picture parts are meaningless images when viewed directly because they are composed of reinforcement signals. Therefore, it is desired to mask with a black level or the like so as not to hinder the viewing of the main screen. However, since the reinforcement signal is superimposed, the black level is not completely obtained, and there is a problem that white noise is conspicuous in a part of the non-image portion due to the pulsed signal waveform.

In order to solve this problem, several methods have been conventionally proposed. Among them, the main ones are as follows. (1) Reduce the level of the reinforcement signal component. (2) Decrease the setup amount of the reinforcement signal. (3) Raise the clamp level of the non-image area. (4) Modulate the reinforcement signal. However, none of them can obtain sufficient effects by themselves, and each has a bad effect. Each adverse effect will be briefly described.

First, there is a method of reducing the level of (1), but there are several methods depending on the means for realizing it. A simple way is to simply reduce the gain. Although this is practical, the level is restored again in the receiver, which causes a reduction in the SN ratio. Therefore, extreme level compression is not possible. Another method is to suppress the generation of the reinforcement signal itself. For example, a pre-filter may be inserted in front of the input of the encoder to suppress the spectral component of the reinforcement signal.
The effect of broadcasting will be weakened.

The method (2) of lowering the set-up of the reinforcement signal restricts the pp value of the reinforcement signal, resulting in a decrease in the SN ratio. In addition, setting up to a negative level adversely affects the sync separation circuit of the receiver. Also, the method of raising the clamp level in (3) is
Depending on the transient response characteristic of the clamp circuit of the receiver, the image on the main screen is adversely affected. Further, although the method of modulating the reinforcing signal of (4) has relatively few adverse effects, the level of the reinforcing signal must be halved when using simple AM modulation. Furthermore, in order to go through the modulation and demodulation,
There is a problem that the effective band is narrowed.

As described above, according to the conventional technique, when wide EDTV broadcast is received by the current television receiver, it is difficult to reduce the noise generated in the non-image part appearing in the upper and lower parts of the main screen. It was

[0014]

In order to solve the above-mentioned problems of the prior art, the present invention provides (1) a video signal of a main screen having a wide aspect ratio and a video signal provided above and below the main screen. A television signal transmission method for transmitting a television signal in a letterbox format in which a reinforcement signal superimposed on an image section is combined, wherein the reinforcement signal generated in a transmitter is linearly converted between a plurality of scanning lines. After performing the arithmetic processing according to, it is combined with the video signal of the main screen, in the receiving device, the signal transmitted by the transmitting device,
Provided is a television signal transmission method characterized by performing a calculation process reverse to the calculation process, and (2) a video signal of a main screen having a wide aspect ratio and a non-image provided on the upper and lower parts of the main screen. A transmission device for transmitting a television signal in a letterbox format in which a reinforcement signal superimposed on a part is combined, wherein the reinforcement signal is a primary conversion circuit that performs arithmetic processing by primary conversion between a plurality of scanning lines, A television signal transmitting apparatus, comprising: a letter box conversion circuit that synthesizes a video signal of the main screen and a signal output from the primary conversion circuit, and transmits the letter box television signal. (3) Letterbox format that combines the video signal of the main screen with a wide aspect ratio and the reinforcement signal that is superimposed on the non-image area provided above and below the main screen. A receiving device for receiving a television signal, wherein the reinforcement signal is subjected to a calculation by a primary conversion among a plurality of scanning lines, and then combined with a video signal of the main screen, and transmitted in a letterbox format television. John signal is received, a video signal of the main screen, a separation circuit for separating into a reinforcement signal that is arithmetically processed by a primary conversion between a plurality of scanning lines, to the reinforcement signal output from the separation circuit,
The present invention provides a receiving device including an inverse linear conversion circuit that performs an arithmetic process reverse to the arithmetic process.

[0015]

According to the present invention, when the wide EDTV broadcast is received by the current television receiver, in order to reduce the noise generated in the non-image areas at the upper and lower parts of the main screen, the transmission side of the television signal is reinforced. The signal is subjected to an arithmetic process by a primary conversion between a plurality of scanning lines, and the receiving side again performs an arithmetic process corresponding to the inverse conversion of the transmitting side. By performing such processing, a signal component localized at a large amplitude, which is likely to be noticed as noise in a non-image portion, is diffused into the block using orthogonal transformation. As a result, the level of the signal in the non-picture part is suppressed and the distribution is smoothed,
Reduces interference in non-image areas.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a television signal transmission method of the present invention,
The television signal transmitting device and the television signal receiving device will be described with reference to the accompanying drawings. 1 is a block diagram showing an embodiment of a television signal transmitting apparatus and a receiving apparatus according to the present invention, FIG. 2 is a diagram showing a filter characteristic used in the operation of Hadamard transform, and FIG. 3 is a diagram showing the operation of Hadamard transform. It is a figure for explaining.

In FIG. 1, the reinforcement signal separated from the original signal of 480 progressive scans on the transmitter side is supplied to an orthogonal transformation matrix circuit (primary transformation circuit) 30.
The reinforcement signal, which has been subjected to the conversion processing described later in the orthogonal transformation matrix circuit 30, is combined with the video signal of the main screen separated from the original signal by the letterboxing circuit 31 as described in the related art and transmitted. It On the receiving device side, the signal obtained by combining the main screen video signal and the reinforcement signal is
The separation circuit 32 separates the main screen image signal and the reinforcement signal again. The separated reinforcement signal is converted into a reinforcement signal before being subjected to conversion processing by the inverse matrix circuit (inverse primary conversion circuit) 33. The video signal of the main screen is supplied to a processing circuit (not shown).

The orthogonal transformation matrix circuit 30 is a circuit which realizes a one-dimensional fourth-order Hadamard transformation with four lines as one block as shown in the equation (1).

[0019]

[Equation 1]

Since the inverse transform matrix of Hadamard transform is equal to the forward transform matrix, the inverse matrix circuit 34 also has the same configuration as the orthogonal transform matrix circuit 30.
From equation (1), y0 = x0 + x1 + x2 + x3 y1 = x0 + x1 -x2 -x3 y2 = x0 -x1 + x2 -x3 y3 = x0 -x1 -x2 + x3, which indicates a filter having the characteristics shown in FIG. ing. That is, the input signal is divided into four signal components in the frequency domain by the four filters shown in FIG. 2 by the one-dimensional fourth-order Hadamard transform. The converted waveform shows a waveform in which the four signal components are histogrammed.

For example, a signal sequence as shown in FIG. 3A is converted into a signal sequence as shown in FIG. 3B by the one-dimensional fourth-order Hadamard transform, and a signal component localized at a large amplitude is converted. Diffusion, level suppression and distribution smoothing are performed. In addition, in the present embodiment, the arithmetic processing of the primary conversion between the plurality of scanning lines has been described by taking the one-dimensional four-dimensional Hadamard conversion of the orthogonal conversion as an example, but the present invention is not limited to this.

Therefore, even if the pulse-like signal waveform is apt to be noticed as noise in the non-picture area, the reinforcing signal is arithmetically processed between a plurality of scanning lines by a primary conversion such as Hadamard conversion, which is relatively easy to perform signal processing. As a result, noise can be reduced.

[0023]

As described in detail above, the television signal transmitting method, transmitting apparatus, and receiving apparatus of the present invention are
It is possible to reduce noise in the non-image area, and wide E
Both DTV broadcasting and current broadcasting are compatible, and wide E
There is a practically excellent effect that the image quality of the DTV receiver can be satisfied.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a television signal transmitter and receiver according to the present invention.

FIG. 2 is a diagram showing a filter characteristic used in the operation of Hadamard transform.

FIG. 3 is a diagram for explaining an operation of Hadamard transform.

FIG. 4 is a diagram showing a conceptual diagram of a letterbox format.

FIG. 5 is a block diagram showing an example of an encoder for wide EDTV broadcasting.

FIG. 6 is a diagram for explaining the operation of the p → i conversion circuit.

FIG. 7 is a diagram showing characteristics of a vertical high pass filter.

FIG. 8 is a block diagram showing an example of a decoder for wide EDTV broadcasting.

[Explanation of symbols]

 30 Orthogonal Transform Matrix Circuit (Primary Transform Circuit) 31 Letterboxing Circuit 32 Separation Circuit 33 Inverse Matrix Circuit (Inverse Primary Transform Circuit)

Claims (3)

[Claims] 1. A television for transmitting a television signal in a letterbox format in which a video signal of a main screen having a wide aspect ratio and a reinforcement signal superposed on a non-image part provided in upper and lower parts of the main screen are combined. A John signal transmission method, wherein the reinforcing signal generated in the transmitting device is subjected to arithmetic processing by a primary conversion between a plurality of scanning lines, and then combined with the video signal of the main screen, and in the receiving device, A method for transmitting a television signal, characterized in that the signal transmitted by the transmitting device is subjected to a calculation process reverse to the calculation process. 2. A transmission for transmitting a letterbox format television signal in which a video signal of a main screen having a wide aspect ratio and a reinforcement signal superimposed on a non-image part provided in upper and lower parts of the main screen are combined. In the device, the reinforcing signal, a primary conversion circuit for performing arithmetic processing by a primary conversion between a plurality of scanning lines, a video signal of the main screen, and a signal output from the primary conversion circuit is synthesized, A television signal transmission device comprising a letterbox circuit for transmitting as a television signal in a letterbox format. 3. A reception for receiving a television signal in a letterbox format in which a video signal of a main screen having a wide aspect ratio and a reinforcement signal superimposed on a non-picture part provided at upper and lower parts of the main screen are combined. In the device, after performing the calculation by the primary conversion of the reinforcing signal between a plurality of scanning lines, is synthesized with the video signal of the main screen, to receive the transmitted television signal in the letterbox format, A separation circuit for separating the video signal of the main screen and the reinforcement signal calculated by the primary conversion between the plurality of scanning lines, and the reinforcement signal output from the separation circuit is subjected to the calculation processing opposite to the calculation processing. A receiving device comprising: an inverse linear conversion circuit for performing the conversion.