JP3054500B2 - Television receiver and television signal conversion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television signal converter for converting a television signal into a second television signal having a different aspect ratio. In particular, MUSE (Multiple Sub-Nyquist-Sam) having an aspect ratio of 16: 9.
pling Encoding) The signal is converted to NTS with an aspect ratio of 4: 3.
The present invention relates to a television converter in a MUSE / NTSC converter for converting into a C signal and a television receiver provided with the television converter.

[0002]

2. Description of the Related Art Hi-vision, which is the next-generation high-definition television, is being broadcast in satellite broadcasting. This Hi-Vision signal is band-compressed by a band compression technique called the MUSE method. The compressed signal (hereinafter, referred to as a MUSE signal) is being broadcast.

[0003] However, since the MUSE broadcast is not compatible with the current television broadcast, it cannot be received by the current television receiver.

[0004] In order to watch the MUSE broadcast on a normal NTSC television receiver, there is a MUSE / NTSC converter 100 as shown in FIG. This MUSE / NTSC converter 100 converts a MUSE signal into an NTSC signal. In addition, this MUSE / NTS
The operation of the C converter is described on pages 31 to 45 of the magazine "Television Technology October 1989" published by Electronic Technology Publishing Co., Ltd.

[0005] The aspect ratio of a Hi-Vision signal is 16: 9 as shown in FIG. 9A. And NTS
The aspect ratio of the C television signal is 4: 3. For this reason, when displaying the current Hi-Vision image on an NTSC television receiver, there is a mode in which the screen on the side of the Hi-Vision screen is truncated as shown in FIG. 9B, and there is no mode above and below the image area a as shown in FIG. 9C. There is a mode (hereinafter, referred to as a wide mode) in which an image area b (visible non-image area) is provided.
Generally, the wide mode shown in FIG. 9C is often used. this is,
This is because there is an advantage that the composition intended at the time of program creation on the transmission side in HDTV is also stored on the reception side.

This is disclosed in Japanese Patent Application Laid-Open No. 2-276368 (H04N 3/223).

However, in the case of the above-described wide mode, the luminance of the non-image area b is set to a low luminance level (for example, a low gray level) in consideration of uneven burning of the CRT phosphor and doming. A difference in luminance level may occur between the non-image area and the image area, and line flicker may occur at the boundary between the two areas.

In order to solve this problem, the present applicant has proposed the following line flicker preventing method in Japanese Patent Application No. 3-212222.

That is, according to the present invention, the MUSE signal input to the MUSE signal input terminal 1 is input to the MUSE / NTSC conversion processing circuit 3 via the A / D converter 2 as shown in FIG. (B-Y) signal and (R-Y) signal of two color difference signals. The counter circuit 8 which has input the horizontal synchronizing signal HD and the vertical synchronizing signal VD
The boundary between the non-image area where no image signal appears and the image area is determined, and a switching signal is output to the switching means 9. The switching means 9 switches between the first and second amplifiers 51 a and 51 b which amplify the luminance signal and have different amplification factors, according to the output of the counter circuit 8. Then, the amplification factor at the upper and lower boundary portions of the image area is reduced.

However, the above-described proposal has the following problems. First, even if the non-image area is set to black, the gain is reduced in order to obtain sufficient flicker reduction. When the brightness of the non-image area is high and the brightness of the image signal at the boundary is high at the amplification factor set in this way, there is a problem that a dark line is generated at the boundary.

On the other hand, when the amplification factor is set so as to suppress the level difference from the image area, flicker occurs when the luminance difference between the non-image portion and the boundary image signal is large. There is a problem that flicker improvement cannot be obtained. Therefore, there is a drawback that the setting of the amplification factor is very difficult.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and an object of the present invention is to prevent flicker at a boundary portion irrespective of a luminance signal level difference between a non-image area and an image area. And

[0013]

SUMMARY OF THE INVENTION The present invention relates to a method for converting an input first television signal of a first system into a second television signal of a second system having a different aspect ratio. In a television receiver including a television signal conversion device that generates a non-picture part area where no image signal appears due to the difference between the signal of the no-picture part area of the second television signal and a boundary part of the picture area. A signal mixed with the image signal is used as a boundary signal between the non-image area and the image area, and the boundary signal is arranged below the boundary portion of the signal of the non-image area in the first field, and in the second field. A television receiver, which is arranged above the boundary portion of the signal in the non-image portion area.

The present invention also relates to a video signal which is obtained by mixing an image signal of the non-image area of the second television signal with an image signal of a boundary portion of the image area in a field of the second television signal. A television receiver is characterized in that at least one boundary portion between the image area and the image area is a boundary signal between the non-image area and the image area.

Further, the present invention provides a method for converting an input first television signal of a first system into a second television signal of a second system having a different aspect ratio by using a difference in the aspect ratio. In a television signal conversion device for generating a non-picture part area where no signal appears, a signal obtained by mixing a signal of the non-picture part area of the second television signal with an image signal of a boundary part of the picture area is used as a non-picture part. A boundary signal between the region and the image region, and the boundary signal is arranged below the boundary portion of the signal of the non-image portion region in the first field, and the boundary signal of the signal of the non-image portion region is disposed in the second field. A television signal converter is provided above a boundary portion.

Further, according to the present invention, a signal obtained by mixing an image signal of the non-image area of the second television signal with an image signal of a boundary portion of the image area in a field of the second television signal is provided. A television signal conversion device characterized in that at least one boundary between the image area and the image area is a boundary signal between the non-image area and the image area.

[0017]

The present invention acts to reduce flicker by reducing the difference in luminance level at the boundary according to the non-image area and the image area.

[0018]

FIG. 1 is a block diagram showing an embodiment of the present invention.

Reference numeral 21 denotes a MUSE to which a MUSE signal is input.
/ NTSC down converter, 22 is a time axis compression circuit for compressing the signal on the time axis, 23 is an image signal in the non-image area, that is, a non-image section creation circuit for creating an image-free area, and 24 is a time axis compressed image signal. An arithmetic circuit that creates a signal at the boundary with the non-image portion, 25 is a sync separation circuit that separates the sync signal from the downconverter 21, and 26 is a 7 / 5-fold horizontal sync signal obtained from the sync separation 25. 7/5 conversion horizontal synchronization signal generation circuit, 27 is a clock generation circuit, 28 is a line counter for counting the horizontal synchronization signal from the horizontal synchronization circuit 26, 29 is a field discrimination circuit, 30 is a control circuit for controlling the switch SW, SW is a switch for switching signals.

Next, the operation will be described with reference to FIGS. First, when the MUSE signal is input to the down-converter 21, the number of scanning lines is reduced and the number of scanning lines is reduced to 480.
A so-called squeeze image signal A (FIG. 3a) of the book is output.
The squeeze image signal A is time-axis-compressed by the time-axis compression circuit 22 to output the image signal A (FIG. 3B).

By the way, conventionally, when the image signal from the down converter 21 is displayed on a normal television receiver, the image signal is displayed in a letter box display (FIG. 3B). 360 scanning lines
It is a book. For this reason, the vertical resolution lowers as the number of scanning lines in the image area portion A decreases.

Therefore, in this circuit configuration, in order to prevent the vertical resolution from deteriorating, a squeeze image signal having 480 scanning lines is used as the output image signal of the down converter 21 and further displayed on a television receiver. In this case, the number of display scanning lines is set to 735, the number of scanning lines (480 lines) of the squeeze image signal is displayed as it is, and the non-image area B is formed above and below.

On the other hand, the non-image portion B generates an image signal of a predetermined level by the non-image portion forming circuit 23 and outputs it. The level of this image signal can be set arbitrarily, and the set level can also be changed.

Further, for the boundary between the image area A and the non-image part B, a boundary image signal C is created by the arithmetic circuit 24. In the arithmetic circuit 24, basically, the image signal A
And the average value of the non-image part B (C = A + B / 2),
Line flicker due to the boundary portion can be prevented, and the line does not become dim.

The horizontal (H) and vertical (V) synchronization signals are extracted from the image signal from the down converter 21 by the synchronization separation circuit 25. Based on the horizontal and vertical synchronizing signals, the frequency of the horizontal synchronizing signal is converted to 7/5 by the horizontal synchronizing signal generation circuit 26 so that the number of scanning lines becomes 735. The horizontal synchronizing signal generation circuit 26 is created based on the clock (960fh) of the clock generation circuit 27.

Then, based on the horizontal synchronizing signal from the horizontal synchronizing signal generation circuit 26, the image signal is compressed in the vertical direction by the time axis compression circuit 22, and the image signal A is output. The image signal is displayed by switching the switch SW in accordance with the scanning line so that the signal generated as described above can be displayed as shown in FIG.

The switching of the switch SW is controlled by the control circuit 30. The control circuit 30 obtains output signals of the line counter 28 and the field determination circuit 29 and outputs a control signal.

That is, the line counter 28 is set to 7/5
The number of scanning lines is counted for each field by the converted horizontal synchronization signal and the vertical (V) synchronization signal, and the current line information is output to the control circuit 30. The field discriminating circuit 29 discriminates odd and even fields from the horizontal (H) and vertical (V) synchronization signals. This field discriminating circuit 2
The determination method of No. 9 is based on the phase difference between the vertical synchronization signal and the horizontal synchronization signal in the odd field and the even field.
(For example, Japanese Utility Model Laid-Open No. 61-40070 (H04N3
The control circuit 30 generates a control signal for switching the switch SW based on signals from the line counter 28 and the field determination circuit 29.

Next, the control operation will be described. FIG.
, The luminance level data (N) of the non-image portion B and the luminance level data (V1 to Vx, V1 ′ to V1) of the image signal A
x '), the upper row shows the data output of the first (odd) field, and the lower row shows the data output of the second (even) field. In the case of FIG. Is simply switched and displayed.

On the other hand, a case where the boundary image signal C is inserted will be described. In FIG. 6, a non-image portion B and an image signal A
(N + V)
1/2, N + V1 '/ 2, N + Vx / 2, N + Vx' /
In 2), control is performed to switch the upper and lower portions of the first field and the second field.

As another method, as shown in FIG. 7, the data (N + V) from the arithmetic circuit 24 is applied only to the boundary between the first field (or the second field).
(、, N + Vx / 2).

In the first method, the flicker is caused by the boundary image signal C (N + V1 / 1) of the first field.
2) occurs in a portion overlapping the non-image portion B (N) of the second field, and a portion overlapping the image signal A (V2) of the first field and the boundary image signal C (N + V1 '/ 2) of the second field, The scanning lines are separated by one line, and are easily left visually. Note that this is the upper side of the screen, but the lower side is also the same.

In the second method, the upper part is improved, but the lower part has no picture area B of the first field.
(N), the image signal A (Vx ′) of the second field, the boundary image signal C (N + Vx / 2) of the first field, and the second
The image signal A (Vx-1) of the field overlaps, causing the same symptom as in the first method. When the boundary image signal C is inserted only into the second field, a symptom occurs on the upper side.

Therefore, in order to solve these symptoms, as shown in FIG. 5, the boundary image signal C is inserted only in the upper part of the first field and the boundary image signal C is inserted only in the lower part of the second field. The switching may be performed as follows. It goes without saying that the boundary image signal C may be reversed.

When the non-image area is located on the upper side as shown in FIG. 11A, the upper boundary part switches the boundary image signal C to only the first field.
In the case of being on the lower stage side as in (b), the lower-stage boundary portion may switch the boundary image signal C to only the second field.

Therefore, line flicker at the boundary between the non-image area and the image area can be prevented in accordance with the image area.

[0037]

According to the present invention, in a MUSE / NTSC converter, when an image having an aspect ratio of 16: 9 is reproduced on a television receiver having an aspect ratio of 4: 3, the boundary between a non-image area and an image area which occurs vertically. Line flicker in a part can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing a display state.

FIG. 3 is a diagram illustrating a conversion method according to the present invention.

FIG. 4 is a diagram for explaining a switching state according to the embodiment of the present invention.

FIG. 5 is a diagram for explaining a switching state of the embodiment of the present invention.

FIG. 6 is a diagram for explaining a switching state according to the embodiment of the present invention.

FIG. 7 is a diagram for explaining a switching state according to the embodiment of the present invention.

FIG. 8 is a configuration diagram of a high-vision reception system.

FIG. 9 is a diagram for explaining a MUSE / NTSC conversion method.

FIG. 10 is a block diagram showing a conventional example.

FIG. 11 is a diagram showing another display state.

[Explanation of symbols]

 Reference Signs List 21 MUSE / NTSC down converter 22 Time axis compression circuit 23 Non-image part creation circuit 24 Arithmetic circuit 25 Synchronization separation circuit 26 7/5 conversion horizontal synchronization signal creation circuit 27 Clock generation circuit 28 Line counter 29 Field discrimination circuit 30 Control circuit SW switch

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/38-5/46 H04N ^7/ 00-7/01

Claims (4)

(57) [Claims] 1. When an input first television signal of a first system is converted into a second television signal of a second system having a different aspect ratio, no image signal appears due to the difference in the aspect ratio. In a television receiver including a television signal conversion device for generating a non-picture area, a signal obtained by mixing a signal in the non-picture area of the second television signal with an image signal in a boundary portion of the image area is used. A boundary signal between the image region and the image region, wherein the boundary signal is arranged below the boundary portion of the signal of the non-image region in a first field, and the signal of the non-image region is arranged in a second field. A television receiver disposed above the boundary portion of the television receiver. 2. The television receiver according to claim 1, wherein a signal obtained by mixing an image signal of the non-image area and an image signal of a boundary portion of the image area of the second television signal is mixed. A television receiver, characterized in that at least one boundary portion between the non-picture area and the image area generated in the field of the second television signal is a boundary signal between the no-picture area and the image area. 3. When an input first television signal of the first system is converted into a second television signal of a second system having a different aspect ratio, no image signal appears due to the difference in the aspect ratio. In a television signal conversion apparatus for generating a non-picture area, a signal obtained by mixing a signal of the non-picture area of the second television signal with an image signal at a boundary portion of the image area is used. In the first field, the boundary signal is disposed below the boundary portion of the signal of the non-image portion area, and in the second field, the boundary signal is disposed with respect to the boundary portion of the signal of the non-image portion region. A television signal conversion device, wherein the television signal conversion device is disposed at an upper position. 4. The television signal converter according to claim 3, wherein a signal obtained by mixing an image signal of the non-image area and an image signal of a boundary between the image areas of the second television signal. Wherein at least one boundary between the non-picture area and the image area generated in the field of the second television signal is a boundary signal between the no-picture area and the image area.