JPH02301271A - Picture display system - Google Patents

Abstract

PURPOSE:To prevent baking caused when a picture with a small size than a screen size is displayed by varying a display start position on a screen of a converted video signal with a display start position designation means. CONSTITUTION:A video signal by the high definition television system such as a MUSE base band signal is converted into a video signal of the existing television system such as an NTSC signal by reducing number of scanning lines without changing the aspect ratio and displayed, then a margin area is caused to the upper side and/or lower side of a picture region on the screen. Then a display start position designation means 10 designating the start position on the screen of the picture area is provided and the relation of position be tween the picture area and the margin area is changed by varying variously the start position of the picture area by the designation means 10 to prevent baking of the screen caused by fixing both the areas.

Description

[Detailed Description of the Invention] [Graduation Field of Application] The present invention provides a method for transmitting video signals based on high-definition television system.
The present invention relates to an image display system that converts into a video signal and displays it according to the current television system, and particularly relates to processing of blank areas and image areas that occur when displaying an image smaller than the screen.

[Conventional technology]

As a new television system to replace the current television system, high-definition television not only improves picture and sound quality, but also provides advanced visual psychological effects such as a sense of presence and impact that far exceeds that of the current television system. For example, a high-definition system has been proposed.

Since the high-definition system is significantly different from the current television system, such as the NTSC system, in its screen system, scanning system, audio system, etc., it is not possible to reproduce high-definition signals as they are using a receiver based on the NTSC system. For this reason, differences in the number of scanning lines, aspect ratio, field frequency, etc. between both systems are absorbed and the high-definition signal is converted to NTSC.
Hi-Vision/NT to convert to signal and display
SC converters (down converters) have been proposed.

Figure 7 is a diagram showing an example of displaying the output of the down converter on an NTSC screen.
This mode reduces the 1,032 effective scanning lines of the SE signal to 173:344 and allocates them among the 485 effective scanning lines of the NTSC side, obtaining NTSC output without changing the aspect ratio of 16:9 of the high-definition system. . According to this mode, the aspect ratio of the NTSC system is 4:3 (16:3).
12), a margin area of about 10% of the effective number of scanning lines appears at the top and bottom of the screen, but since the horizontal direction matches that of a high-definition screen, it is possible to obtain an image with the intended composition in high-definition. .

[Problem to be solved by the invention]

By the way, in the conventional example mentioned above, the blank areas that occur at the top and bottom of the screen are displayed with a black signal, so if this display continues for a long time, the degree of fatigue of the phosphor in the picture tube will differ between the blank area and the image area. Therefore, when normal display using the entire screen is performed, there is a problem that the margin area becomes bright and streaks appear at the boundary of the area. This is what is called CRT burn-in.

An object of the present invention is to prevent burn-in phenomenon that occurs when displaying an image smaller than the screen size.

[Means to solve the problem]

The present invention provides a method for changing the display start position of the converted video signal on the screen when converting and displaying a video signal according to the high-definition television system into a video signal according to the current television system without changing the aspect ratio. By changing the display start position specifying means, the positional relationship between the image area and the margin area on the screen is changed in the vertical direction.

[For production]

Video signal based on high-definition television system, e.g. MU
When the SE baseband signal is converted to a video signal according to the current television system, such as an NTSC signal, by reducing the number of scanning lines without changing the aspect ratio and displayed, the upper and/or lower part of the image area on the screen A blank area appears.

Therefore, the present invention provides a display start position specifying means for specifying the start position of the image area on the screen, and by changing the start position of the image area variously by this specifying means, the positional relationship between the image area and the margin area is adjusted. This is to prevent screen burn-in caused by fixation of the double head area.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of an image display method according to the present invention. This embodiment shows an example in which a MUSE signal obtained by band-compressing a high-definition signal for satellite broadcasting is converted into an NTSC signal and displayed.

In FIG. 1, a MUSE baseband signal received by a BS antenna and obtained through a BS chainer passes through a low-pass filter 1 with a cutoff frequency of 8.15 MHz, and then is converted into a digital signal by an AD converter 2. A.D.
The sampling frequency in converter 2 is the resampling frequency of MUSE 16.2MH2.

The MUSE signal converted into a digital signal by the AD converter 2 is de-emphasized by a de-emphasis circuit 3 and then supplied to a vertical filter 4 .

The vertical filter 4 generates a 1-line signal from the 3 lines of the Musg signal and performs effective scanning vAIO32 of the MUSE signal.
The number of lines is reduced by 1/30344 lines, and the generated luminance signal Y9 color difference R-Y and B-Y of each line is supplied to the time axis buffer 5. The time axis buffer 5 is a field memory that sequentially stores luminance signals and color difference signals for one field. , 15.12 (=16.2X14
/15) A read address signal RA having a clock frequency of MHz is used to read a signal from the storage location. The details of the scanning line conversion in the vertical filter 4 and the time axis buffer 5 can be found in Japanese Patent Application No. 1983-242605 (title of invention: rM) previously filed by the applicant.
This method is disclosed in detail in "UsE-NTSC Conversion System").

The signal read out from the time axis buffer 5 by the successive address signal RA is converted into an NTSC format by adding a horizontal synchronization signal HD and a vertical synchronization signal VD in the NTSC format.
The signal is converted into an analog signal by the DA converter 7, which samples the signal at a frequency of 7.56 MHz, and then supplied to the NTSC receiver 8.

On the other hand, the MU converted into a digital signal by the AD converter 2
The SE signal is supplied to the MUSE timing generation circuit 9. This MtJSE timing generation circuit 9 is MU
A horizontal synchronization signal and a frame pulse as a vertical synchronization signal are detected from the SE signal to generate various timing signals, and the AD converter 2. The vertical filter 49 is supplied to the time axis buffer 5 and the NTSC timing generation circuit 10, which will be described later.

The horizontal synchronization signal is inserted into each line of the MUSE transmission signal from the 1st sample point to the 11th sample point with the polarity reversed for each line, and from this horizontal synchronization signal 16.2M
Regenerate the Hz resampled signal. Further, the frame pulse is inserted into each frame of the MUSE transmission signal using two lines. Since the waveforms of these two lines have opposite polarities, they can be easily distinguished from the video signal, and thereby the frame pulse (=vertical synchronization signal) can be detected accurately.

The NTSC timing generation circuit 10 generates various timing signals based on the synchronization signal detected by the MUSE timing generation circuit 9 and the generated timing signal,
The time axis buffer 5 receives a successive address signal RA with a frequency of 15.12 MHz, the NTSC formatter 6 and the NTSC
horizontal and vertical synchronization signals HD and VD, D to the receiver 8;
A sampling signal SP2 with a frequency of 7.56 MHz is supplied to the A converter 7.

FIG. 2 is a block diagram showing a partial configuration of the NTSC timing generation circuit 10, in which the timing signal TM is shown.

A circuit for generating a successive address signal RA, a horizontal synchronization signal HD, and a vertical synchronization signal VD is shown.

This circuit generates a plurality of timing signals T based on the outputs of horizontal and vertical counters 20 and 21 and vertical counter 21.
a-=Tn; a plurality of image display timing generation circuits 22a to 22n; a plurality of timing signals Ta;
A selector 23 that selects any one timing signal from xTn and outputs it as a timing signal TM, and a selector 23 that generates successive address signals RA for the time axis bar 5 based on the output of the horizontal counter 20 and the timing signal TM. Address generation circuit 24, both counters 20 and 2
The synchronization signal generation circuit 25 generates horizontal and vertical synchronization signals HD and VD from the output of the signal generator 1.

The horizontal counter 20 divides the 15.12 MHz input chronograph signal to 15.75 KHz (=15.12 MHz
z/960) horizontal scanning signal, and vertical counter 2
Supply to 1. The vertical counter 21 counts the horizontal scanning signals to output line data indicating line numbers for 1 fields, and outputs it to the image display timing generation circuits 22a to 22n. Timing generation circuit 22
A to 22n generate timing signals Ta to Tn having mutually different phases based on the supplied line data.

The timing signal TaxTn has 344 lines per frame (172 lines per field) in order to display the video signal stored in the time axis puff sofa 5 using 344 lines out of 485 effective scanning lines (1 frame) of the NTSC system. As shown in the waveform diagram of FIG. 3, the signal is at level "1" during the period of 1), and is generated with a phase shift of a plurality of lines from each other, as shown in the waveform diagram of FIG. The selector 23 selects a plurality of timing signals 'ra-
'rnO selects one timing signal and outputs it as a timing signal TM. The selection of the timing signal T a w T n in the selector 23 may be performed randomly, for example, in connection with power-on of the system.

The timing signal TM selected in this way is supplied to the successive address generation circuit 24. The successive address generation circuit 24 outputs an address signal RA, which is reset each time the timing signal TM arrives and increases sequentially from the first value, at a frequency of 15.12 MHz, and supplies it to the time axis buffer 5 to generate 344 signals in one frame ( 1 field 172 pieces)
Read out the video signal.

FIG. 4 is a block diagram showing the configuration of the NTSC formatter, which adds the first and second selectors 30 and 31, the margin level generator 32, the blanking level generator 33, and the horizontal and vertical synchronizing signals HD and VD. It consists of an OR circuit 34 that generates a blanking signal BL.

The first selector 30 switches between the video signal read from the time axis buffer 5 and the video signal output from the margin level generator 32 using the above-mentioned timing signal TM, and the period when the timing signal TM is at level "1" is a time period. The timing signal TM of the video signal from the axis buffer 5 is at level r.
During the OJ period, the video signals from the margin level generator 32 are output. Therefore, the output of the margin level generator 32 is set to the same level as the brightness level of the image area,
If the hue is also inconspicuous, the brightness level of the entire screen is averaged, and screen burn-in is reduced compared to the conventional method in which blank areas are displayed at a black level.

The second selector 31 switches the output from the first selector 30 and the output from the blanking level generator 33 using the blanking signal BL, and outputs the blanking signal B.
During the period when L is level “1”, blanking level generator 3
The blanking level signal from the selector 30 is selected during the period of level "0", and the video signal from the selector 30 is selected during the period of level "0", and the blanking signal is added to the video signal and output.

Next, the operation of this embodiment having such a configuration will be explained.

The M U S and E baseband signals inputted through the BS tuner are converted into 3 lines/1 line by the vertical filter 4 to generate 344 effective scanning lines from 1032 effective scanning lines. Luminance signal Y of each generated line
1 color difference signals R-Y and B-Y are sequentially sent to the time axis buffer 5.
will be written to. The signal written in the time axis buffer 5 is read out by the successive address signal RA which is output during the period when the timing signal TM is at level "1", and is
It is supplied to the formatter 6. NTSC formattuta 6
Then, the video signal of the margin area and the blanking signal are added and output as an NTSC video signal.

By the way, since the timing signal TM is a signal selected from a plurality of timing signals TaxTn as described above, for example, if the timing signal Ta is selected, the fifth
As shown in figure (a), an image is displayed at the top of the screen,
Moreover, if the timing signal Tn is selected, FIG.
As shown in 1, an image is displayed at the bottom of the screen. Therefore, by appropriately switching the timing signal TM, the positional relationship between the image area and the margin area can be variously changed on the screen, and screen burn-in caused by fixing the margin area can be reduced.

FIG. 6 is a block diagram showing another embodiment of the NTSC timing generation circuit 10. This embodiment uses a plurality of image display timing generation circuits 22a to 22 in the configuration shown in FIG.
An image display timing generation circuit 22 and an n-1 stage shift register 26 for delaying the output of the generation circuit 22 are provided in place of the generation circuit 22 and the shift register 26.
The configuration is such that each output is supplied to the selector 23 as timing signals Ta to Tn.

〔Effect of the invention〕

According to the image display method according to the present invention, when displaying an image smaller than the screen, the image is displayed using the entire screen by appropriately changing the positional relationship between the image area and the margin area without fixing it. This makes it possible to prevent burn-in caused by partial use of the screen.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the image display method according to the present invention, FIG. 2 is a block diagram showing a partial configuration of the NTSC timing generation circuit in FIG. 1, and FIG. 3 is the operation of FIG. 2. FIG. 4 is a block diagram showing the NT and SC formatters in FIG. 1. FIG. 5 is a diagram showing an example of displaying an image projected on an NTSC receiver according to the present invention. FIG. 7 is a block diagram showing another embodiment of the NTSC timing generation circuit, and FIG. 7 is a diagram showing an example of displaying an image displayed on an NTSC receiver according to the conventional method. Patent applicant Pioneer Corporation NTSC Formatsuta Figure 4 NTSC timing generation circuit Figure 2 Waveform diagram Figure 3 Screen display example Figure 5 Other examples of NTSC timing generation circuit Figure 6 Conventional screen display example Figure 7

Claims (1)

[Scope of Claims] In an image display method that converts a video signal according to a high-definition television system into a video signal according to a current television system without changing the aspect ratio and displays the converted video signal on a screen, An image display method characterized in that a positional relationship between an image area and a margin area on the screen is changed in the vertical direction by changing a display start position on the screen using a display start position specifying means.