JPH02268579A - Image display position controller - Google Patents

Abstract

PURPOSE:To eliminate difference of brightness at a part always being displayed and a part not being displayed by masking by shifting the phase of a masking signal at every constant time. CONSTITUTION:The converter of a video signal having different aspect ratio and number of scanning line is equipped with a conversion means 14 and a masking signal generating means 20 to mask a part not being displayed on a screen. Also, it is equipped with control means 16 and 17 which shift a phase in which the output signal of the conversion means 14 appears on the screen by a constant quantity at every constant time by controlling the masking signal generating means 20, a masking level generating means 20, and a signal selection means 20. In such a way, since the masking signal can be moved on a display screen vertically and horizontally, it is possible to moderate the difference of steep deterioration in the fluorescent plane of a boundary part, and to prevent a burning mark from being conspicuous.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Industrial Application Field) The present invention provides a high-definition television signal having a larger number of scan lines and aspect ratio than that of a standard television signal. , relates to an image display position control device that converts into a standard television signal.

(Prior Art) In recent years, high-definition television systems have been developed in various countries, and in Japan there is a high-definition television system proposed by the Japan Broadcasting Corporation. This system is not compatible with the current standard television system,
Furthermore, since the aspect ratio is different, the signal as it is cannot be displayed on a standard television display device.

Furthermore, high-definition television receivers are currently expensive and it will take time for them to become widely available.

Therefore, there is a need for a means, that is, a signal conversion device, which allows high-definition television broadcast signals to be displayed even on a standard television receiver.

In a signal device that converts a high-definition television signal (1125 scanning lines, aspect ratio 18:9) to a standard television signal (525 scanning lines, aspect ratio 4:3), the screen display after conversion. The following two methods can be considered.

A method of displaying a screen with an aspect ratio of 16:9 as shown in Figure 3 (A) by cutting off the top, bottom, left and right information as shown in Figure 3 (B) to correspond to the aspect ratio of the standard television system. As shown in FIG. 3(C), this is a method of compressing a high-quality television signal while maintaining the aspect ratio of the signal and displaying it without missing information.

Here, a conventional example of the latter method of compressing a high-definition television signal while maintaining its aspect ratio and displaying it without missing information will be described.

FIG. 8 shows a television signal converter for converting a high definition television signal into a standard television signal.

As a high-definition television signal, it has more scanning lines and a wider aspect ratio than a standard television signal (for example, an NTSC television signal), and uses a dot interlaced system to combine two color difference signals ((R-Y) signal and ( B-Y
) signal) becomes line sequential, and T CI (TiIle C
Some are encoded using the impressed Integratin method.

The high-definition television signal is input to an analog-to-digital (hereinafter referred to as A/D) converter 51 via an input terminal 50 and converted into a digital signal.

The sampling clock Φ1 here is, for example, Φ1−
It is 18.2MH.

The digitized signal is input to the input processing device 52 at the next stage. Here, for example, de-emphasis and transmission reverse gamma correction are performed. At the same time, the digitized signal is input to the synchronization signal generator 53. Here, 11
A synchronization signal for the 25-line television signal and a synchronization signal for the 525-line television signal are generated to synchronize the system and both signals.

The output signal of the input processing device 52 is processed by the two-dimensional interpolation filter 5
4 is input. The two-dimensional interpolation filter 54 includes a plurality of line memories that delay a high-definition television signal by one horizontal scanning period, a delay circuit that delays the output signal of each line memory by one horizontal sample, a coefficient multiplier, and an adder. configured. As a result, interpolation processing using upper, lower, left, and right data within the same field is performed in common for both luminance signals and color difference signals, and furthermore, vertical weighting is performed in order to display using the method shown in Figure 3 (C). be exposed.

Due to the above field interpolation, the number of data is doubled,
The sampling clock rate of the A/D converter 51 is Φ1
Then, the clock rate of the interpolated output data is
2Φ1 (for example, 32.4M1lz).

The output signal of the two-dimensional interpolation filter 54 is input to a time axis conversion device 55. Here, processing is performed to convert one horizontal scanning time of a high-definition television signal into one horizontal scanning time of a standard television signal. For this purpose, field memory 56 is used. For example, one horizontal scanning time in the MUSE method is about 29 ns, and the sampling clock in the NTSC method is about 82 ns. Also MUS
The sampling clock of the E method is Φ2 - approximately 32.4M
, Hz, and the writing is done at this rate and the NTS
The sampling clock of C method is Φ3 - about 30.0M!
Iz, and reading is performed at this rate.

Further, in the time axis conversion device 55, the luminance signal and the color difference signal are also separated, and the luminance signal is inputted to the luminance signal output processing device 57, and the color difference signal is inputted to the color difference signal output processing device 5.
8 is input. The luminance signal output processing device 57 performs signal conversion suitable for output. The color difference signal output processing device 58 performs TCI decoding and time axis expansion.

That is, the color difference signal (R-Y) signal and (B-Y) signal are time-compressed during the horizontal blanking period of the luminance signal, and are
/4 and multiplexed, and (RY) signal and (B-
Since the Y) signal is line sequential, it is decoded.

The color difference signal output processing device 58 uses a line memory, in which input data is written at a frequency of a write clock (approximately 308 IIZ) and read out at a clock frequency of 1/4 of that frequency.

As a result, the color difference signals for one horizontal scanning time, which have been time-compressed to 1/4 as a high-definition television signal, are each expanded to one horizontal scanning time of a standard television signal. Also, among the (RY) signal and the (B-Y) signal, the signal that is not present in the current line is interpolated using the signals of the upper and lower lines, and the two color difference signals are converted into sequential scanning signals. .

The output luminance signal (Y signal) from the luminance signal output processing device 57 and the output color difference signal (Y signal) from the color difference signal output processing device 58
The R-Y) signal and the B-Y signal are input to digital-to-analog (D/A) converters 59a, 59b, and 59c, respectively, and are converted into analog signals. As a result, the output terminals 60a, 60b, and 60c output Y signals, (R-Y) signals, and (B-Y) signals according to the standard television system.
Each signal is output.

(Problems to be Solved by the Invention) When masking is performed using the conventional conversion method described above to obtain a display screen as shown in FIG. ), deterioration (burn-in) progresses faster than the masked area. This deterioration becomes significant when projection is performed for a long time. Here, a screen with the same aspect ratio as the display screen of this cathode ray tube,
When displaying a television signal, the boundary between the area exposed to the electron beam and the masked area is
Differences in deterioration appear, and differences in screen brightness appear at the border, making it unsightly.

Therefore, this invention aims to solve the problem that due to the difference in deterioration of the fluorescent screen between the part where the image is always displayed and the part where it may not be displayed due to masking, a difference in brightness occurs when the image is displayed on both parts at the same time. It is an object of the present invention to provide a video display position control device that can eliminate the problem of image display position.

[Structure of the Invention] (Means for Solving the Problem) This invention provides first
A device for converting a video signal into a second video signal, comprising: converting means for converting the first video signal into scanning lines and horizontal scanning times of the second video signal; When displaying on an output device having a signal aspect ratio, a masking signal generating means for masking a portion of the output signal of the converting means that is not displayed on the screen, and controlling the masking signal generating means to control the output of the converting means. control means for horizontally or vertically shifting the phase in which the signal appears on the screen by a fixed amount at fixed time intervals; masking level generating means for outputting the luminance signal level or hue level during the masking period; and the conversion means in response to the masking signal. The masking level generation means includes signal selection means for selecting and outputting an output signal of the means and an output signal of the masking level generation means.

(Function) By using the above method, the masking signal can be moved vertically or horizontally on the display screen, so the phosphor screen at the boundary can be moved more quickly than when the projected area of the image is fixed. Differences in deterioration can be alleviated. Also, during the mask period, the masking level generation means
Any brightness and hue can be set, and images can be projected even during the mask period, making burn-in marks less noticeable.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.

A high-definition television signal is input to an analog-to-digital (hereinafter referred to as A/D) converter 11 via an input terminal 10 and converted into a digital signal.

The sampling clock Φ1 here is, for example, Φ1−
It is 16.2MH.

The digitized signal is input to the input processing device 12 at the next stage. Here, for example, de-emphasis and transmission reverse gamma correction are performed. At the same time, the digitized signal is input to the synchronization signal generator 24. Here, 11
A synchronization signal for the 25-line television signal and a synchronization signal for the 525-line television signal are generated to synchronize the system and both signals.

The output signal of the input processing device 12 is processed by a two-dimensional interpolation filter 1
3 is input. The two-dimensional interpolation filter 13 includes a plurality of line memories that delay a high-definition television signal by one horizontal scanning period, a delay circuit that delays the output signal of each line memory by one horizontal sample, a coefficient multiplier, and an adder. configured. As a result, interpolation processing using upper, lower, left, and right data within the same field is performed in common for both luminance signals and color difference signals, and furthermore, vertical weighting is performed in order to display using the method shown in Figure 3 (C). be exposed.

The above field interpolation doubles the number of data, and A
If the sampling clock rate of the /D converter 11 is Φ1, the clock rate of the interpolated output data is 2.
Φ1 (for example, 32.4 MHz).

The output signal of the two-dimensional interpolation filter 13 is input manually to the time axis conversion device 14 . Here, processing is performed to convert one horizontal scanning time of a high-definition television signal into one horizontal scanning time of a standard television signal. For this purpose, field memory 15 is used. For example, one horizontal scanning time in the MUSE method is about 29 ns, and the sampling clock in the NTSC method is about 82 ns. Also MUS
The sampling clock of the E method is Φ2 - approximately 32.4M
Hz, the writing is done at this rate, and the NTSC
The sampling clock of the method is Φ3 - approximately 30.0MHz
, and reading is performed at this rate.

Further, in the time axis conversion device 14, the luminance signal and the color difference signal are also separated, and the luminance signal is inputted to the luminance signal output processing device 18, and the color difference signal is inputted to the color difference signal output processing device 1.
9 is input. The luminance signal output processing device 18 performs signal conversion suitable for output. The color difference signal output processing device 19 performs TCI decoding and time axis expansion.

That is, the color difference signal (R-Y) signal and the (B-Y) signal are time-compressed during the horizontal blanking period of the luminance signal, for example, 1
/4 and multiplexed, and (RY) signal and (B-
Since the Y) signal is line sequential, it is decoded.

In the color difference signal output processing device 19, a line memory is used, and input data is written in this memory at a frequency of a write clock (approximately 30 MHz), and read out at a clock frequency that is 1/4 of that frequency.

As a result, the color difference signals for one horizontal scanning time, which have been time-compressed to 1/4 as a high-definition television signal, are each expanded to one horizontal scanning time of a standard television signal. Also, among the (RY) signal and the (B-Y) signal, the signal that is not present in the current line is interpolated using the signals of the upper and lower lines, and the two color difference signals are converted into sequential scanning signals.

The output luminance signal (Y signal) from the luminance signal output processing device 18 and the output color difference signal (Y signal) from the color difference signal output processing device 19
The R-Y) signal and the B-Y signal are input to the screen mask signal adding device 20.

FIG. 2 shows a specific example of the screen mask signal adding device 20. As shown in FIG.

As shown in Figure 3 (C), if you try to compress a high-definition television signal with its aspect ratio intact and display it in the center of a standard television screen,
It is necessary to create masking areas at the top and bottom.

For this purpose, the timing signal generator 16 (shown in FIG. 1) generates two signals (a blanking signal 30 and a masking signal 31) as shown in FIGS. 4(A) and 4(B).

The blanking signal 30 is transmitted during a video scanning period (for example, 52.
7us), it becomes low (L) level, and during the horizontal blanking period (e.g. 10.8us) and vertical blanking period (e.g. 4211 horizontal scanning period), it becomes high (H) level.
) level. On the other hand, the masking signal 31
is a signal that is at H level during the masking period and is at L level during the projection period (for example, 340H horizontal scanning period).

In FIG. 2, processing of the luminance signal will first be explained.

A blanking signal 30 is input as a select signal to the selector 22a. The selector 22 is set to select and output a certain level A when the blanking signal 30 is at the L level, and to select and output a certain level B when the blanking signal 30 is at the H level. The output of the selector 22a is supplied to one of the selectors 21a. Here, level A is the signal level of the luminance signal during the video scanning period, and level B is the signal level during the horizontal blanking period, and these are for matching with the clamp level of the monitor.

Next, the blanking signal 30 and the masking signal 31 are supplied to the NOR circuit 24. Here, exclusive OR processing is performed on the blanking signal 30 and the masking signal 331, and a signal 32 as shown in FIG. 4(C) is obtained. This signal 32 is always at a low level during the masking period (shaded area) shown in FIG. 3(C) (FIG. 4(C)). This signal 32 is then supplied to the selector 21a as a select signal. selector 21
a selects the signal from the brightness signal output processing device 18 when the signal 32 is at the H level, and selects the signal from the selector 22a (level A or level B when the signal 32 is at the L level).
) and derive it.

Therefore, the output video signal of the selector 21a is as shown in FIG.
). This signal is supplied to the digital-to-analog converter 23a, converted into an analog signal, and output as a luminance signal Y to the output terminal 24a.

The (RY) signal from the color difference signal output processing device 19 and the (B
-Y) signals are also processed in the same way.

That is, the (RY) signal is supplied to one of the selectors 21b, and the output signal (level C or D) from the selector 22b is supplied to the other of the selectors 21b. The selector 22b is controlled by a blanking signal 30,
When the blanking signal 30 is at a high level, level D is selected and derived, and when it is at a low level, level C is selected and derived.

Further, the selector 21b is controlled by a signal 32, and when the signal 32 is at a low level, it selects the output of the selector 22b, and when it is at a high level, it selects and derives the (RY) signal.

Selector 21c and selector 22c are similarly controlled by signal 32 and blanking signal 30, respectively. The selector 22c selects and derives level F when the blanking signal 30 is at a high level, and selects and derives level E when it is at a low level. Also selector 21c
is derived by selecting the output of the selector 22c when the signal 32 is at a low level, and selecting the (B-Y) signal when it is at a high level. Therefore, the mask portion can be colored in any color by setting the level.

Here, the outputs of the selectors 21b and 21c are supplied to digital-to-analog converters 23b and 23c, respectively, and converted into analog signals.

Here, if the high level position of the blanking signal 30, that is, the masking interval, is shifted in time, the third
The boundary between the hatched area (mask area) and the image projection area shown in FIG. 3(C) can be moved up and down.

FIG. 5 shows the relationship between one field period of the video signal and the masking signal 31. If the masking signal 31 is always generated at the position shown in FIG. 3(B) with respect to the video signal (FIG. 3(A)), the masked portion (shaded portion) and projected portion ( (blank area) is fixed.

However, if the positions shown in Figures (C) and (D) are moved at regular time intervals, the boundaries will not be fixed. However, the period of movement (reciprocating) is
It is better to select a period that is not noticeable (not unsightly) on the display screen.

To cause the masking signal 31 to reciprocate over time as described above, a timing generator 16 (shown in FIG. 1) is used.
may be controlled by, for example, the microcomputer 17. For example, a preset value may be switched for a counter for generating a masking signal provided inside the timing generator 16, or a logical operation may be performed on the output data of the counter and the output thereof may be used as a masking signal. In this case, the generation position of the masking signal 31 can be shifted by switching the logical configuration. Here, the amount of movement and the timing of switching are determined by the flowchart of the microcomputer 17.

FIG. 6 shows an example of a flow chart for masking signal control in the microcomputer 17.

That is, in step S1, the horizontal line is moved by m942 (towards the bottom of the screen, for example) and the time is measured (step S1).
2), and in step S3, it is determined whether the edge of the masking signal 31 is at the same time as the edge of the video signal (the upper line or lower line on the screen). This can be easily determined, for example, by logically determining whether a predetermined horizontal line and an edge pulse of the masking signal exist at the same time. If it is determined in step S3 that a predetermined line of the video signal and an edge of the masking signal are present at the same time, the process moves to step S4, and the direction of movement of the position of the masking signal is switched.

By controlling the masking signal 31 in this way,
The boundary portion moves up and down as time passes, and the formation of abrupt changes in the fluorescent screen is alleviated.

In the above embodiment, the boundary portion is moved by controlling the generation timing of the masking signal 31, but the same effect is not limited to this, and the same effect can be obtained by switching the entire field period of the video signal up and down every few fields. Of course. In this case, as shown in FIG. 7, the position of the entire image is moved up and down with respect to the display screen to an unnoticeable extent, thereby preventing the boundary portion from remaining at a specific fluorescent screen position.

Although the above embodiment shows an example in which the mask portions appear vertically, the present invention is not limited to this and can be applied to a system that obtains mask portions on the left and right sides using the same concept. The present invention is not limited to the device, but can be applied to any system for obtaining a mask portion in general.

[Effects of the Invention] As explained above, according to the present invention, due to the difference in deterioration of the fluorescent screen between the part where the image is always displayed and the part where the image is sometimes not displayed due to masking, the image can be displayed simultaneously on both parts. It is possible to eliminate differences in brightness that occur when images are projected.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a specific circuit example of the screen mask signal adding device of FIG. 1, and FIG. 3 is an explanation of the operation of the time axis conversion device. 4 is a timing chart shown to explain the operation of the circuit of FIG. 2; FIG. 5 is a timing chart shown to explain the operation of the device of the present invention;
FIG. 6 is also a flowchart shown to explain the operation of the apparatus of the present invention, FIG. 7 is an explanatory diagram shown to explain another embodiment of the invention, and FIG. 8 is a conventional television signal conversion method. FIG. 2 is a configuration explanatory diagram showing the device. DESCRIPTION OF SYMBOLS 11... Analog-digital converter, 12... Input processing device, 13... Two-dimensional interpolation filter, 14... Time axis conversion device, 15... Field memory, 16...
- Timing generator, 17... Microcomputer, 18... Luminance signal output processing device, 19... Color difference signal output processing device, 20... Screen mask signal addition device,
23a, 23b, 23c...digital analog converter. Applicant's agent Patent attorney Takehiko Suzue (A) Condolences (C)

Claims (2)

[Claims] (1) A projection part that displays an image on the screen by adding a masking signal to the image signal in the middle of the image output path;
In an image display device that obtains a masked portion that does not display an image, in order to prevent the boundary between the projected portion and the masked portion from becoming a fixed position on the screen, the entirety of the video signal and the masking signal or the masking signal is The phase of only
An image display position control device characterized by comprising position control means that shifts the position at regular intervals. (2) In a device that converts a first video signal to a second video signal having a different aspect ratio and number of scanning lines, the first video signal is converted into the scanning line and horizontal scanning time of the second video signal. converting means; generating a masking signal for masking a portion of the output signal of the converting means that is not displayed on the screen when displaying the first video signal on an output device having an aspect ratio of the second video signal; a masking signal generating means; a control means for controlling the masking signal generating means to shift the phase in which the output signal of the converting means appears on the screen horizontally or vertically by a fixed amount at fixed time intervals; and a luminance signal during the masking period. A masking level generating means for outputting a level or a hue level; and a signal selecting means for selecting and outputting an output signal of the converting means and an output signal of the masking level generating means in response to the masking signal. An image display position control device characterized by: