JPH10232646A - Display mode discriminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the uneven luminance among respective PDPs by discriminating display mode (Vista, normal, cinema) of an input video signal based on the number of pixel data of the video signal and controlling respective PDPs(plasma display panels) constituting a multipanel. SOLUTION: A video signal is converted into a digital signal with an A/D converting part 1 to be inputted to an adding counter 3. An enable signal for specifying a period when a difference is generated in numbers of pixel data of the video signal by the modes is generated in an addition enabling signal generating part 2 and pixel data from the A/D converting part 1 are added in the adding counter 3 in the period of the enable signal. The processing of the video signal is performed so as not to commit an error in discriminating the mode of the signal by the instantaneous fluctuation of the content of the video signal by subtracting the threshold read out from a threshold storage part 5 from data from the adding counter 3 in a threshold subtracting part 4 to be integrated in an integration part 6 and video signals of R, G, B are processed by controlling a display pixel converting part 8 via a control part 7 to drive the PDPs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display mode discriminating apparatus, which controls the brightness of each plasma display panel (PDP) constituting a multi-panel screen in accordance with the display mode, and discriminates the display mode of a video signal. About what you do.

[0002]

2. Description of the Related Art In a multi-panel system in which a single image is displayed by combining a plurality of PDPs, an APC (Automatic Power Control) circuit is provided in each PDP unit, and a PD is provided.
Measure the current supplied to P, and if the measured value is greater than or equal to the required value,
When this state continues for a required time (for example, 4 to 5 seconds), the brightness is reduced, the current flowing into the PDP is limited, and the deterioration of the PDP due to the high brightness state continuing for a long time is prevented. The current flowing into the PDP is substantially proportional to the display ratio of the video signal (the ratio of the integrated value of the luminance level of the video signal of all pixels on one screen to the integrated value of the luminance level of the all-white video signal).

For example, as shown in FIG. 3, a multi-panel screen is composed of nine PDPs having an aspect ratio of 16: 9 and various display types, for example, a normal type (an aspect ratio of 4: 3, and thereafter). , Normal), Vista type (16: 9, hereinafter referred to as Vista) and Cinema type (Approx. 2.7: 1, hereinafter referred to as cinema). , P surrounded by D
The image is displayed in all areas from DP to normal, but the image is displayed in an area surrounded by i, J, K, and L in normal, and in an area surrounded by E, F, G, and H in the case of cinema. . For this reason, in other PDPs other than the PDP, there is a portion (black image) displayed in black according to the display mode, and the apparent display ratio changes depending on the display type. Thus, for example,
If a video signal with the same luminance gradually increasing at the same time on the entire screen is input, Vista
The PC circuit starts operating at the same time, but in normal and cinema, the APC circuit of the other PDP starts operating later than the PDP or the like.
Luminance difference between P, and other PDP (luminance unevenness)
And PDP in the case of cinema, and other PDPs
And a luminance difference is generated between them.

[0004]

SUMMARY OF THE INVENTION In view of the above, the present invention has been made in view of the above points, and has a display type (normal type,
Vista type, cinema type)
An object of the present invention is to make it possible to correct the display ratio of each PDP constituting a multi-panel screen according to a display type, and to eliminate a luminance difference between PDPs.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an A / D converter for converting an analog video signal into a digital signal, and a pixel data of the video signal from the A / D converter. An addition enable signal generation unit for generating an enable signal for specifying an addition period, and an addition counter for adding pixel data of a video signal from the A / D conversion unit with a signal from the addition enable signal generation unit. A display mode discriminating device for discriminating a display mode based on a signal from an addition counter.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a display mode discriminating apparatus according to the present invention, a video signal is converted into a digital signal by an A / D converter, and a period for adding pixel data of the video signal from the A / D converter is designated. Signal is generated by the addition enable signal generation unit, and pixel data of the video signal from the A / D conversion unit is added by the addition counter during the period of the enable signal from the addition enable signal generation unit. The threshold value read from the threshold value storage unit is subtracted from the threshold value by the threshold value subtraction unit, the signal from the threshold value subtraction unit is integrated for a required time, and a display mode determination signal is output.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a display mode discriminating apparatus according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of a main part of an embodiment of a display mode discriminating apparatus according to the present invention. In the figure, reference numeral 1 denotes an A / D converter, which converts an analog video signal into a digital signal. Reference numeral 2 denotes an addition enable signal generation unit that generates an enable signal for designating an addition period of pixel data of the video signal from the A / D conversion unit 1 based on a synchronization signal input together with the video signal. Reference numeral 3 denotes an addition counter, and an addition enable signal generation unit 2
During the period of the enable signal, the pixel data of the video signal from the A / D converter 1 is added. Reference numeral 4 denotes a threshold value subtraction unit that subtracts data read from the threshold value storage unit 5 from data from the addition counter 3. The threshold storage unit 5 stores criteria for distinguishing display modes. Reference numeral 6 denotes an integrating unit that integrates data from the threshold value subtracting unit 4 so that mode switching does not occur when the video content fluctuates sharply. A control unit 7 determines a display mode based on data from the integration unit 6 and controls the display pixel conversion unit 8. The display pixel converter 8 processes the red, green, and blue video signals in accordance with the display mode.

Next, the operation of the display mode discriminating apparatus according to the present invention will be described. A / D converter 1 converts analog video signals
, And is input to the addition counter 3, and the pixel data of the video signal is added during the period when the enable signal is applied from the addition enable signal generation unit 2.
The addition enable signal generation unit 2 generates an enable signal for specifying a period during which pixel data of the video signal from the A / D conversion unit 1 is added by the addition counter 3 based on a synchronization signal input together with the video signal. The addition period of the pixel data is determined by an addition counter 3 based on a normal mode having an aspect ratio of 4: 3, a Vista mode having an aspect ratio of 16: 9, and a cinema mode having an aspect ratio of about 2.7: 1.
Are set so that the added value of the different values becomes different values. This is because, for example, as shown in FIG. 2, in the case of normal, there is an image during almost the entire period (1 V) of vertical scanning, whereas in the case of Vista, the beginning (left side) and end of vertical scanning (Horizontal line) has no image (black image), and the period of the image is further narrowed in cinema. Therefore, the addition enable period is set as shown in the figure. Then, by adding the pixel data of each set period, a different value is output from the addition counter 3 depending on the display mode, and the display mode can be determined from this data.

However, the above-mentioned aspect ratio is not determined by a standard or the like, and there is a slight difference depending on the image source. ), It is sometimes difficult to determine the display mode only from these data. Therefore, a threshold value for distinguishing the addition value of each display mode is set, stored in the threshold value storage unit 5, and the threshold value subtraction unit 4 subtracts the threshold value from the data from the addition counter 3 to determine an error in the display mode. Not to occur. For example, when the number of bits of the pixel data is 8 bits,
This number of bits is not required for the display mode determination signal. For this reason, the threshold value subtracting section 4 performs bit subtraction and outputs data of 5 bits or the like. The enable period of the signal generated by the addition enable signal generation unit 2 can be set arbitrarily, or the threshold of the threshold storage unit 5 can be rewritten to arbitrary data, and a new display mode or a different aspect ratio is used. It may be possible to cope with this when processing a video signal.

Then, in order to prevent erroneous determination that the display mode has changed, for example, when the video content fluctuates sharply due to flashing or the like, the data from the threshold value subtraction section 4 is integrated by the integration section 6 and the control section. 7, a display mode discrimination signal is output, the display pixel converter 8 is controlled, and the input image of each PDP constituting the multi-panel is controlled in accordance with the display mode. Prevent luminance difference (luminance unevenness) from occurring.

FIG. 3 shows a PDP 9 having an aspect ratio of 16: 9.
Since the aspect ratio of the multi-panel is 16: 9, for example, when the input video signal is a Vista, an image is displayed in the entire range, and when the input video signal is normal, i, i FIG. 4 shows that images are displayed in a range surrounded by J, K, and L, and in the case of a cinema, in a range surrounded by E, F, G, and H.
Is an example in which a multi-panel is composed of nine PDPs having an aspect ratio of 4 to 3 ('to'). The aspect ratio of the multi-panel is also 4: 3. Shaded area (i ', J', B ', A'
And the area surrounded by D ', C', K ', and L') are black images. In the case of cinema, the left and right hatched portions (i ', J', F ', E ’,
And H ', G', K ', and L') indicate black images.

[0012]

As described above, according to the display mode determining apparatus of the present invention, the display mode of the input video signal is determined and each PDP constituting the multi-panel screen is controlled. It is possible to prevent a luminance difference (luminance unevenness) from occurring between PDPs depending on the mode. Also, by appropriately setting the threshold value for the display mode determination, it is possible to absorb variations in the signal processing circuits such as the A / D converter, and the setting of the threshold value can be changed. In addition, by appropriately setting the addition area of the pixel data, it is possible to prevent the display mode from being erroneously determined.

[Brief description of the drawings]

FIG. 1 is a main block diagram of an embodiment of a display mode discriminating apparatus according to the present invention.

FIG. 2 is an explanatory diagram of an addition enable period of the display mode determining device according to the present invention.

FIG. 3 is an explanatory diagram of a display range for each display mode.

FIG. 4 is an explanatory diagram of a display range for each display mode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 A / D conversion part 2 Addition enable signal generation part 3 Addition counter 4 Threshold subtraction part 5 Threshold storage part 6 Integral part 7 Control part 8 Display pixel conversion part

Claims (7)

[Claims] An A / D converter for converting an analog video signal into a digital signal, and an addition enable signal for generating an enable signal for designating an addition period of pixel data of the video signal from the A / D converter. A generation unit, and the A / D
A display mode discriminating apparatus, comprising: an addition counter for adding pixel data of a video signal from a conversion unit with a signal from an addition enable signal generation unit, wherein a display mode is determined based on a signal from the addition counter. 2. The addition enable signal generation unit according to claim 1, wherein an addition value of the addition counter is set to a normal mode having an aspect ratio of 4: 3, a Vista mode having an aspect ratio of 16: 9, and a cinema mode having an aspect ratio of about 2.7: 1. 2. The display mode discriminating apparatus according to claim 1, wherein a signal for designating different values is generated. 3. The image processing apparatus according to claim 2, wherein
2. The display mode discriminating apparatus according to claim 1, wherein an enable signal for an arbitrarily set period is generated. 4. A threshold value storage unit for storing a threshold value used as a reference for determining a display mode, and a threshold value subtraction unit downstream of the addition counter for subtracting data read from the threshold value storage unit from data from the addition counter. 4. The display mode discriminating apparatus according to claim 1, wherein the data is output from a threshold value subtracting unit. 5. The image processing apparatus according to claim 1, wherein the threshold value storage unit has an aspect ratio of 4 to 3.
5. The display mode determining apparatus according to claim 4, wherein a threshold value for determining a normal mode, a Vista mode having an aspect ratio of 16: 9, and a cinema mode having an aspect ratio of about 2.7: 1 is stored. 6. The display mode discriminating apparatus according to claim 4, wherein a threshold value stored in said threshold value storage unit can be arbitrarily rewritten. 7. An image processing apparatus according to claim 4, further comprising an integrating section that integrates a signal from the threshold subtracting section for a required time after the threshold subtracting section, and determines a display mode based on the signal from the integrating section. The display mode determining device according to claim 5 or 6.