JPH03226087A - High picture quality tv signal/tv signal converter - Google Patents

Abstract

PURPOSE:To suppress flicker at a border by using a line counter so as to count the number of horizontal scanning lines of a television receiver and selecting a background signal whose luminance level is sequentially increased or decreased in response to the line number from a background signal generating circuit and outputting and displaying the result. CONSTITUTION:The above converter is provided with a background signal generating circuit 6 and an output control circuit 7 controlling an output of a picture signal based on the count value of a line counter 5. The counter 6 counts a horizontal synchronizing signal by one frame. Then a decoder 10 based on the count of the counter 6 detects a line displaying the background and displaying a converted picture signal. When a high picture quality TV pattern is displayed on a TV screen whose aspect ratio is 3:4 and the count value by the line counter 6 is within a 1st range, the output control circuit 7 outputs a background signal whose luminance level is sequentially increased and displays the signal. Moreover, when the count value is within a 2nd range, the background signal whose luminance level is sequentially decreased is outputted. Thus, the luminance change due to fluctuation in the border is less and flicker is suppressed.

Description

Detailed Description of the Invention [Industrial Application Fields] The present invention is a high-definition TV signal/TV signal converter, particularly for suppressing screen flicker when displaying a wide aspect ratio high-definition TV screen on a TV screen. The present invention relates to a high-quality TV signal/TV signal converter.

[Prior art] NT is the standard TV system currently used in the country.
The SC system was adopted in the United States in 1953, but as screens have become larger in recent years, its resolution has become increasingly lacking.

On the other hand, recent advances in electronics have been remarkable, including semiconductor technology and satellite transmission technology.
In order to solve the above-mentioned lack of resolution, several new high-quality images have been proposed.

Such high-definition TVs include, for example, high-definition and MAC (Multiple Analog C).
component), EDT V (Exte
In particular, high-visibility screens have a screen with an aspect ratio of 9=16, which is wider than the NTSC system, and the number of scanning lines is 1125. NTSC
This method is attracting attention because it has approximately twice the number of 525 lines and can provide high image quality comparable to that of 35 mm film.

However, these high-quality images such as high-definition
V-dedicated receivers (decoders) and receivers are relatively expensive, and therefore there is a demand for a converter that can receive these high-quality TV images even with current TV receivers.

There are several methods for such high-definition TV signal/TV signal converters, but the so-called wide mode method, which displays a wide aspect ratio high-definition screen as is on a 3:4 aspect ratio TV screen, requires programming. It has the advantage of preserving the intended composition, so its practical value is high.

FIG. 3 shows an example in which a high-definition screen with an aspect ratio of 9:16 is displayed on a current TV screen with an aspect ratio of 3:4 using such a high-quality TV signal/TV signal converter. Since the screen in the horizontal and vertical directions is compressed and fitted into a 3:4 screen, there are no images in the upper and lower portions 1 and 2 of the screen, and this portion is usually set to a black background.

FIG. 4 shows the waveform of the signal converted by the converter to display such an image portion and a background portion. For example, in the case of high-definition, the image signal is MUSE
(Multiple Sub-Nyquist-9am
However, this MUSE signal is converted to NTSC using a conversion processing section that includes a vertical filter, a time axis conversion circuit, etc.
This signal is converted into a signal that can be received by current TV receivers and becomes an image partial signal.

On the other hand, the background partial signal is created separately from the image partial signal and added to a predetermined line on the screen.

In addition, in FIG. 4, only the upper background portion 1 is shown, and an example is shown in which this blank level background portion signal is added to lines 1 to n of the odd field and to lines 264 to n+263 of the even field. There is.

[Problems to be Solved by the Invention] As described above, in the conventional high-quality TV signal/TV signal converter, the background partial signal and the image partial signal are distinguished and processed in each of the odd and even fields, but this When interlaced scanning is performed using such a signal, flicker occurs at the boundary between the background portion and the image portion, resulting in an extremely unsightly problem.

In other words, in interlaced scanning, the odd field is scanned in 1/60 seconds, and then the even field is scanned in 1/60 second. If there is a large level difference, the boundary portion will move up and down in 1/30 seconds, causing flicker. FIG. 5(A) shows an image obtained by a conventional high-quality TV signal/TV signal converter, and FIG. 5(B) shows a partially enlarged view of the boundary between the background part and the image part. The boundary moves up and down at the 1/2 line portion 3, causing flicker.

The present invention has been made in view of the above-mentioned conventional communication, and its purpose is to provide a high-quality TV signal/TV signal converter capable of suppressing flicker occurring at the boundary between a background portion and an image portion. purpose.

[Means for Solving the Problems] In order to achieve the above object, the high-quality TV signal/TV signal converter of the present invention includes a line counter that counts the number of horizontal scanning lines of a TV receiver, and a blank level. a background signal generation circuit that generates a background signal having a plurality of brightness levels from to a maximum level; and when the number of lines counted by the line counter is within a first range, the brightness level increases sequentially according to the number of lines. selects and outputs a background signal from the background signal generation circuit, and when the number of lines is within a second range, selects and outputs a background signal whose brightness level sequentially decreases according to the number of lines from the background signal generation circuit; The image forming apparatus is characterized in that it further includes an output control circuit that outputs an image signal when the number of lines is other than the above.

[Function] The high-definition TV signal/TV signal converter of the present invention has such a configuration, and when displaying a high-definition TV screen on a TV screen with an aspect ratio of 3:4, the high-definition TV signal/TV signal converter of the present invention has the following configuration: That is, the background is displayed at the top and bottom of the screen, and changes in the brightness level at the boundary between the background portion and the image portion are reduced.

That is, a background signal that increases a plurality of brightness levels to H is generated from the background generation signal, but when the count value of the line counter is within the first range, the output control circuit outputs a background signal that increases the brightness level sequentially. and display. Further, when the count value of the line counter is within the second range, the output control circuit outputs a background signal whose brightness level decreases sequentially.

As a result, there is no large change in the brightness level between the background signal and the image signal at the boundary between the image part and the background part, and even if interlaced scanning is performed, there is little change in brightness due to fluctuations in the boundary, making it possible to suppress flicker. can.

[Embodiment] Hereinafter, a preferred embodiment of the high-definition TV signal/TV signal converter according to the present invention will be described with reference to the drawings, taking a high-definition TV as an example.

FIG. 1 is a block diagram of the configuration of this embodiment. A high-definition image signal with an aspect ratio of 9:16 and a number of scanning lines of 1125 is band-compressed by the MUSE method, transmitted, and input to the conversion processing section 4 similar to the conventional one. This conversion processing section 4 includes an A/D converter, a vertical filter, an NTSC
It has an encoder, and converts the MUSE image signal into an image signal that can be received by an NTSC TV receiver, such as converting the number of scanning lines from 1125 to 525. In other words, a screen with an aspect ratio of 9:16 is changed to an aspect ratio of 3:4.
In order to display the image on the screen, 1125 image signals are converted into 392 image signals.

The image signals converted into the NTSC system are manually input to the image memory 5 field by field in the order of odd fields (196 lines) and even fields (196 lines).

Further, a background signal generation circuit 6 is provided which generates a background signal for displaying a background at the top and bottom of the TV screen.
level, 12.5 level, 25 level, 50 level 5
A background signal having stepped brightness levels can be generated.

Now, the characteristic feature of this embodiment is that an output control circuit 7 is provided which controls the output of the background signal generation circuit 6 and the image signal based on the count value of the line counter 5. This output control circuit 7 switches the background signal having each brightness level from the background signal generation circuit 6.
It consists of a terminal switch SWI, a two-terminal switch SW2 that switches between the signal from this SWl and an image signal, and a decoder 8 that controls switching of these switches SWI and SW2 based on the count value from the line counter 5. .

The number of horizontal scanning lines in the 525 system is counted by a counter 6, and the count output is output to a decoder 10. That is, counter 6
counts 525 525 horizontal synchronization signals for one frame. Then, the decoder 10 detects the line displaying the background and the line displaying the converted image signal based on the count of the counter 6, and also detects the line displaying the background signal by changing the luminance level, which is a feature of the present invention. Detect. For example, when displaying the background on lines 1 to n in an odd field, in one frame period, 1 to n (background part) are detected, n+1 to n+196
(odd field image part) detection, n+197 to n
+263 (background part at end of odd field and beginning of even field) detection, n+264 to n+459
(even field image part) detection, n+460~5
25 (background part at the end of even field) is detected. Furthermore, if the number of lines to be displayed by changing the brightness level of the background signal is, for example, four, the decoder 10
Detection of 3 to n (odd field), n+197 to n+2
00 (odd field) detection, n+260-n+2
63 (even field) detection, n+460 to n+46
3 (even field) is detected. This decoder 1
0 controls the readout of the image memory 5 and the switches SWI and sw2 based on the above detection results.

Now, when the number of lines counted by the line counter 5 is 1 to n-4, SWI is connected to the ■ side by the control signal from the decoder 8, and SW2 is also connected to the ■ side. Then, no image signal is output, and only the background signal having a blank level from the background signal generation circuit 6 is output.
Kurosei Saiai is displayed on the TV screen.

When the count reaches n-3, the SWI is switched to the ■ side by the control signal from the decoder 8. Then, a background signal having a 5°3 level is output from the background signal generating circuit 6, and a background whose brightness is slightly higher than the blank level is displayed on the TV screen.

Then, every time the count increases from n-3 to n, the decoder 8 sends a control signal to change SWl to ■=■-
Switch sequentially from ■ to ■. Then, the background signal generation circuit 6
From 5,2 level-12°5 level-25 level-
A background signal whose luminance level increases from 50 levels is output, and the luminance of the background portion of the TV screen increases successively.

When the number of lines continues to count and reaches (n+1) or more, the decoder 8 sends a control signal and switches SW2 to the ■ side. Then, the background signal from the background signal generation circuit is not output, and only the image signal is output.

FIG. 2 shows the waveform of the signal thus output to the output terminal. FIG. 2(A) shows the signal waveform of the odd field processed as described above, and FIG. 2(B) shows the signal waveform of the even filter processed in the same manner. The image signal starts from the (n+1) line ((n+264) line in an even field) as described above, or starts from several lines of the background signal that displays the background ((n-4) to (n-4) in an odd field).
Ω line and even field (n+259) to n+2
It can be seen that the brightness level of line 63 increases sequentially from 01, that is, the blank level, to the maximum brightness level of 50 to 6, that is, the 50th level.

Then, when performing interlaced scanning of odd and even fields and displaying them on a TV receiver, there is no large difference in brightness level at the boundary between the background area and the image area, so this boundary is reached within 1.1730 seconds. Even if the brightness changes, there is little change in brightness, making it possible to suppress flicker.

The count at line counter 5 continues (this progresses, n+1
When the number reaches 97 to n+200, the decoder 8 sends a control signal according to the number of lines, and changes the SWI to 2-(3)-■→,
5-■, and then switch SW2 to the ■ side.

Then, from the background signal generation circuit 6, 50 levels → 25
Level → 12.5 level → 5.2 level → A background signal in which the blank level and brightness level decrease sequentially is output, and T
A background portion whose brightness gradually decreases is displayed on the V screen.

Then, as in the case described above, when performing interlaced scanning of odd and even fields and displaying them on a TV receiver, there is no large difference in brightness level at the boundary between the background part and the image part, so 1/ Even if this boundary changes within 30 seconds, there is little change in brightness, making it possible to suppress flicker.

[Effects of the Invention] As explained above, the high-quality TV signal/
According to the Tv signal converter, the brightness level of the background portion can be changed stepwise, flicker can be suppressed, and a clear screen can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a configuration of an embodiment of the high-definition TV signal/TV signal converter according to the present invention, FIG. 2 is a signal waveform diagram in the same embodiment, and FIG. 3 is a conventional high-definition TV signal/TV signal converter. FIG. 4 is an explanatory diagram showing an example of display by the TV signal converter, FIG. 4 is a signal waveform diagram by the conventional converter, and FIG. 5 is an explanatory diagram of flicker generation by the conventional converter. 4... Conversion processing unit 5... Line counter 6... Background signal generation circuit 7... Output control circuit 8... Decoder

Claims (1)

[Claims] An image signal of a high-definition TV screen having a predetermined aspect ratio is
It has a conversion processing unit that converts the image signal into an image signal that can be received by the V receiver, and uses the converted image signal to improve the image quality.
A high-quality TV signal/TV signal converter that displays a V screen on a TV screen with an aspect ratio of 3:4 includes a line counter that counts the number of horizontal scanning lines of the TV receiver, and a brightness level from a blank level to a maximum brightness level. a background signal generation circuit that generates a background signal having a plurality of brightness levels up to;
When the number of lines is within a second range, a background signal whose brightness level increases sequentially according to the number of lines is selected and output from the background signal generation circuit, and when the number of lines is within a second range, the brightness level increases sequentially according to the number of lines. an output control circuit that selects and outputs a decreasing background signal from the background signal generation circuit and outputs an image signal when the number of lines is other than the above, and the output control circuit outputs an image signal when the number of lines is other than the above. High image quality T characterized by displaying a background that changes in stages
V signal/TV signal converter.