JP2005017715A - Device and method for correcting surface unevenness - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface unevenness correcting device capable of reducing the luminance unevenness and color unevenness. <P>SOLUTION: The surface unevenness correcting device is equipped with an input means of inputting an image displayed on a display panel as the image data, a correcting means of setting a plurality of divided correction points on the display surface of the display panel, generating correction data for correcting surface unevenness of pixels corresponding to the respective correction points by using the image data, and also generating correction data by varying the correction data values of a plurality of correction points in an array direction by the differences with specified intervals when correction data of a plurality of adjacent correction points are regularly arranged having previously set differences, an interpolation data generating means of generating interpolation data for correcting the surface unevenness of pixels by performing interpolation processing for intermediate pixels positioned between the plurality of correction points by using the correction data of the mutually adjacent correction points, and an output means of outputting a surface unevenness correction signal to the display panel by using the correction data and interpolation data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image display device such as a liquid crystal projector, and more particularly to a surface unevenness correction device and a surface unevenness correction method for correcting luminance unevenness and color unevenness occurring in a display image.
[0002]
[Prior art]
Conventionally, there is a liquid crystal projector as an image display apparatus using a liquid crystal panel. This liquid crystal projector separates light from a light source into light of three primary colors (R, G, B), irradiates these three primary color lights to liquid crystal panels for R, G, B, respectively, and each liquid crystal panel is R, G, By driving with the B signal, R, G, B light whose intensity is modulated is emitted, and the emitted light is synthesized and projected onto the screen.
[0003]
On the other hand, in the liquid crystal panel, it is desirable that the thickness of the liquid crystal layer is generally uniform. However, even in the same liquid crystal panel, uneven luminance is partially uneven because the thickness is different between the peripheral portion and the central portion of the panel. May occur. In addition, luminance unevenness may occur depending on the characteristics of the three primary color lights separated from the light source. The luminance in units of planes is not uniform, and the occurrence of unevenness is unavoidable at present. When these luminance unevenness occurs in the liquid crystal panel for R, G, and B, color unevenness occurs in the projected image. Hereinafter, such luminance unevenness or color unevenness is collectively referred to as surface unevenness.
[0004]
Conventionally, in order to reduce the luminance unevenness, a method is known in which the state of luminance unevenness of each liquid crystal panel is measured, a signal for correcting the luminance unevenness is generated according to the measurement result, and superimposed on the video signal. In other words, the image for adjustment is projected from the projector onto the screen, the image displayed on the screen is photographed by the camera, and the image is taken into the adjustment device as image data, and the brightness levels at multiple points on the liquid crystal panel are measured. A correction signal corresponding to the difference between the reference level and the reference level is generated, and the correction signal is superimposed on the video signal supplied to the liquid crystal panel to reduce luminance unevenness.
[0005]
In generating the correction signal, as the number of the correction points is increased, the correction accuracy of luminance unevenness is improved, but the amount of correction data is also increased in proportion thereto. Therefore, at present, the display screen is divided at certain intervals to set a plurality of correction points, a correction signal is generated for each point, correction is performed, and correction signals are generated by interpolation between the correction points. I am doing so.
[0006]
However, when such an interpolation method is used, streak-like noise may occur on a screen in which luminance unevenness is corrected. For example, as shown in FIG. 7A, a case where correction is applied to a display panel composed of vertical n lines and horizontal m pixels will be described as an example. Correction points are indicated at predetermined intervals as indicated by black circles in the figure. It is assumed that there is an interpolation point indicated by a white circle between the correction points. Then, as shown in FIG. 7B, the difference in the correction data between adjacent correction points is set to a value that is different only in the minimum unit (for example, 0 and 1), and the relationship is arranged regularly and continuously as shown in the figure. And
[0007]
At this time, a correction value is set by interpolation processing for an intermediate pixel between correction points. However, since the setting value of adjacent correction points is different by only 1 LSB (Least Significant Bit), the interpolation data is 0. One of the values of 1 is applied (the figure shows an example in which the small font is set to 0). When such correction is performed, a streak-like noise Y as if a vertical line was drawn is seen.
[0008]
At present, the resolution of luminance unevenness is mainly 10 bits, and if there is a resolution of 10 bits normally, it is recognized as a smooth change in human vision and there is no unnaturalness. If the video output resolution is 10 bits, the change is considered to be below the human visual detection limit even when adjacent pixels differ by only 1 LSB of the minimum unit. However, it has been found that when the same values are continuously arranged as shown in FIG. 7B, the human visual sensitivity becomes very high and is detected.
[0009]
Therefore, when the difference in the correction data between adjacent correction points is set to a value that differs only by 1 bit as the minimum unit, and the relationship is arranged regularly and continuously as shown in the figure, the corrected display screen has vertical lines. Unevenness of the surface appears.
[0010]
Therefore, in order to reduce such streaky surface unevenness, Patent Document 1 discloses that the pixels of the display panel are divided into a plurality of groups in the line direction, and each group is divided into a plurality of blocks along the horizontal direction. In this example, correction points are formed so that the division position of each block is different between adjacent groups, or the division positions of each block are different between fields.
[0011]
[Patent Document 1]
JP-A-11-202827 (FIGS. 3 to 5)
[0012]
[Problems to be solved by the invention]
In the color unevenness correction circuit shown in Patent Document 1, streaky color unevenness can be reduced, but there is a disadvantage that the circuit configuration becomes complicated. SUMMARY OF THE INVENTION An object of the present invention is to provide a surface unevenness correction device capable of reducing luminance unevenness and color unevenness with a simple circuit configuration.
[0013]
[Means for Solving the Problems]
The invention according to claim 1 is a surface unevenness correction device for a display panel constituted by a plurality of pixels arranged in a horizontal direction and a vertical direction,
Input means for capturing video displayed on the display panel as image data;
A plurality of correction points that are divided in advance are set on the display surface of the display panel, and correction data for correcting the surface unevenness of the pixel corresponding to each correction point is generated using the image data, and a plurality of adjacent correction points are generated. When the correction data of the correction points are regularly arranged with a preset difference, correction data obtained by changing the correction data values of the plurality of correction points in the arrangement direction by the difference at a predetermined interval Correction data generating means for generating
In order to perform surface unevenness correction on the intermediate pixels located between the plurality of correction points, complement processing is performed using correction data of correction points adjacent to each other, and complementary data for correcting surface unevenness of the intermediate pixels is generated. Interpolation data generating means for
And output means for outputting a surface unevenness correction signal to the display panel using the correction data from the correction data generation means and the interpolation data from the interpolation data generation means.
[0014]
According to a fourth aspect of the present invention, when the correction data is generated, if the correction data of a plurality of adjacent correction points are regularly arranged with a preset difference, the adjacent arrangement is performed. A correction data generation unit is provided for generating correction data in which correction data values of a plurality of correction points in a direction are changed by the difference in a predetermined field unit.
[0015]
Further, the invention according to claim 7 is a method for correcting surface unevenness of a display panel constituted by a plurality of pixels arranged in a horizontal direction and a vertical direction,
Measuring the luminance level of the correction point set in advance divided into a plurality on the display surface of the display panel;
Correction data for correcting the brightness level of each correction point so as to approach a reference value is generated, and correction data of a plurality of adjacent correction points are regularly arranged with a preset difference. In this case, a correction data generation step for generating correction data in which correction data values of a plurality of correction points in the arrangement direction are changed by the difference at predetermined intervals;
An interpolation step of performing interpolation processing using correction data of adjacent correction points to generate interpolation data in order to perform surface unevenness correction on intermediate pixels located between the plurality of correction points;
And correcting the luminance level of the display panel using the correction data generated in the correction data generation step and the interpolation data generated in the interpolation step.
[0016]
In the invention according to claim 8, when generating correction data, when correction data of a plurality of correction points adjacent to each other are regularly arranged with a preset difference, the arrangement direction is set. The correction data is generated by changing the correction data values of a plurality of correction points at a predetermined field unit by the difference.
[0017]
According to the surface unevenness correcting apparatus and the surface unevenness correcting method, even when correction data of a plurality of adjacent correction points are regularly arranged with a preset difference, Interpolation data can be changed to different values alternately, and streak-like noise can be made invisible.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a video display device provided with the surface unevenness correcting apparatus of the present invention, and FIG. 2 is a block diagram showing the surface unevenness correcting apparatus.
[0019]
FIG. 1 is an overall block diagram of a video display device, which includes a liquid crystal projector 11, a screen 21, a camera 31, and a correction device 41 that generates a surface unevenness correction signal.
[0020]
The liquid crystal projector 11 includes an optical box 12, a light source 13, and a projection lens 14. A liquid crystal panel 15 is provided in the optical box 12, and a video signal from the video signal processing circuit 16 is supplied to the liquid crystal panel 15. It is like that. The video signal processing circuit 16 is supplied with a signal from the signal source 17 and a correction signal for correcting surface unevenness from the correction device 41.
[0021]
The liquid crystal panel 15 is composed of three liquid crystal panels for R, G, and B, and spectral means (dichroic mirror) that splits the light from the light source 13 into R, G, and B light and enters each liquid crystal panel. Etc.) and combining means (cross prism or the like) for combining the light emitted from the respective liquid crystal panels and guiding them to the projection lens 13 are shown for the sake of convenience. Thus, the image projected from the projection lens 14 is displayed on the screen 21.
[0022]
Next, an outline of surface unevenness correction of the liquid crystal panel 15 will be described. For example, when the liquid crystal panel 15 has uneven brightness, the liquid crystal projector 11 projects an image (for example, an all-white image) based on a signal for correcting the uneven surface and displays it on the screen 21. The camera 31 captures the projected video and supplies the captured video signal to the correction device 41. The correction device 41 detects a state of uneven brightness on the screen 21 and generates a correction signal for correcting the uneven brightness.
[0023]
The correction signal is supplied to the video signal processing circuit 16 of the liquid crystal projector 11 to correct the luminance of the uneven luminance portion on the liquid crystal panel 15 and correct the luminance of the liquid crystal panel surface as a whole. Note that a display 50 may be connected to the correction device 41 so that the brightness unevenness correction state can be confirmed.
[0024]
FIG. 2 is a block diagram showing a specific configuration of the correction device 41. In FIG. 2, reference numeral 42 denotes an A / D conversion circuit that converts a video signal from the camera 31 into a digital signal. The A / D conversion circuit 42 generates image data (luminance data). This image data is supplied to the point data extraction circuit 44 at the next stage. The point data extraction circuit 44 is also supplied with horizontal and vertical synchronization signals H and V, and is further connected to a clock circuit 43 that generates a clock signal ck synchronized with the horizontal synchronization signal H.
[0025]
The point data extraction circuit 44 extracts luminance data of a plurality of correction points (that corresponds to a plurality of correction points on the display surface of the liquid crystal panel 15) set at predetermined intervals on the video imaged by the camera 31. Therefore, the position in the horizontal direction can be set by counting the clock ck, and the position in the line direction (vertical direction) can be set by counting the horizontal synchronization signal H, whereby a plurality of corrections can be made. Extract brightness data at points. In addition, field discrimination is performed using the vertical synchronization signal V.
[0026]
The luminance data of each correction point extracted in this way is sent to the correction data calculation circuit 45 in the next stage. The correction data calculation circuit 45 compares the luminance data of each correction point with the reference data, calculates correction data corresponding to the difference for each correction point, and stores it in the memory 46.
[0027]
The operation of the point data extraction circuit 44, the correction data calculation circuit 45, etc. is controlled by the microcomputer 48, and the correction data of the points located between the respective correction points is calculated by interpolation and stored in the memory 46. Yes. In this way, each correction point and the correction data for each point located between them are sequentially read out from the memory 46, converted into an analog signal by the D / A conversion circuit 47, and supplied to the video signal processing circuit 16. Become.
[0028]
The D / A conversion circuit may be provided in the video signal processing circuit 16. In this case, the data read from the memory 46 is supplied to the video signal processing circuit 16 as it is, and the video signal processing circuit 16 The D / A conversion circuit converts the signal into an analog signal, and superimposes a surface unevenness correction signal on the video signal.
[0029]
FIG. 3 is a diagram for explaining the interpolation data calculation method described above, and FIG. 4 is a flowchart showing the flow of interpolation processing by the microcomputer 48.
[0030]
For example, as shown in FIG. 3A, a case where correction is applied to a display panel composed of vertical n lines and horizontal m pixels will be described as an example. A plurality of correction points are set at predetermined intervals as indicated by black circles in the figure. It is assumed that there is an interpolation point indicated by a white circle between each correction point. Then, as shown in FIG. 3 (b), the difference in correction data between adjacent correction points is set to a value that differs only by 1 bit as a minimum unit (for example, 0 and 1), and the relationship is regularly and continuously as shown in the figure. Suppose they are lined up.
[0031]
At this time, for the video component (pixel) between the correction points, correction data is calculated by interpolation processing. However, since the correction data between adjacent correction points is different by only 1 LSB, interpolation is simply performed when interpolation is performed. Either 0 or 1 is applied to the data (see FIG. 7). This will cause streaky vertical noise. Therefore, in the present invention, when the correction data of the correction points adjacent to each other is different only by the minimum unit of 1LSB and is regularly arranged continuously, the data value of every other correction point in the arrangement direction is set to 1. The interpolation data values are alternately changed one by one in the arrangement direction.
[0032]
That is, as can be seen from FIG. 3B, for example, among a plurality of correction points arranged in the column direction, the correction data in a certain column direction is “0”, and the correction data in the column direction adjacent to them is “0”. When the Mycolo computer 48 determines that the value is “1” and is continuous, the correction value 1 is added to every other column for the correction data “1” to obtain “2”, and interpolation processing is performed. To do. As a result, the interpolated data has an intermediate value “1” between “0” and “2”, so that the interpolated data in the column direction alternately changes to different values. For this reason, when viewed in the column direction, it is not linear, and streak-like noise is not visible.
[0033]
Of the correction data that are regularly arranged side by side, if the value of one column is 3, the value of the other column is 4, and the difference between them is 1 LSB, then one column The correction data value may be decreased by 1 to “2”, or the correction data value of the other column may be increased by 1 to “4”.
[0034]
FIG. 4 is an operation flowchart of the correction device 41. When the surface unevenness correction operation starts in step S1, image data from the camera 31 is fetched in step S2, and the state of surface unevenness is detected in step S3. Calculate and create correction data at correction points. In the next step S4, a portion where the same correction data continues is detected based on the calculation result of the correction data, and in step S5, it is determined whether or not the correction data of adjacent correction points are continuously arranged.
[0035]
If the correction data is not continuously arranged, the correction data is left as it is (step S6), and interpolation data is created in S7 in the next interpolation processing step. If it is determined in step S5 that the correction data is continuously arranged, the process proceeds to step S8, and it is determined whether or not the difference between the correction values of the data arranged side by side is the minimum value (1LSB). If the difference is 2LSB or more, the process proceeds to step S6. If the difference is 1LSB, the value is changed by 1LSB every other consecutively arranged portion of the previously created correction data in step S9. Interpolate with.
[0036]
Thus, the correction data of each correction point and the interpolation data between the correction points calculated by the interpolation process are sent to the liquid crystal projector 11 in step S10, and the process ends (step S11).
[0037]
When calculating the interpolation data in this way, by judging the status of the correction data at each correction point and changing the interpolation value, the human visual sensitivity returns to normal, and is detected as a line by the law of detection limit. This eliminates the occurrence of streak-like noise. Further, although the value of the correction data is increased (or decreased) by 1, this is not detected because it is not continuous according to the above-mentioned detection limit law.
[0038]
In the above description, the case where the same data continues in the vertical (column) direction has been described. However, the case where the same continuity occurs in the horizontal (row) direction can be dealt with.
[0039]
Next, another embodiment of the present invention will be described with reference to FIG. In the first embodiment, the example in which the surface unevenness correction is performed by two-dimensional processing has been described, but the example in FIG. 5 performs three-dimensional processing.
[0040]
That is, in FIG. 5, when the correction data between adjacent correction points is different by only 1 LSB and the same data continues in the column direction (or row direction), the increase (or correction data) in the field unit of the video (or The interpolation data is generated by performing an interpolation operation.
[0041]
FIG. 5 shows correction data and interpolation data values in consecutive sequential video fields. In the first field, correction data “0” and “1” at adjacent correction points are used as they are for complementation. As a result, the complementary data is “0”. In the next second field, among the adjacent correction points, 1 is added to the correction data of “1”, and then the complementary data is obtained. Has changed to “1”. In the third field, the same process as the previous field is performed. By sequentially changing the complementing method in units of fields in this way, it is possible to make the boundary of correction appearing as a line inconspicuous.
[0042]
FIG. 6 shows an operation flowchart in the case where the complementary processing as shown in FIG. 5 is performed. In FIG. 6, Step S9 is changed to Step S19 in the flowchart of FIG. 4, and the portion where the created correction data is continuously arranged is changed by 1 LSB value on one side every other field, There is a feature in that the process is led to step S7 and complement processing is performed.
[0043]
In the above description, the surface unevenness correction of the three-plate liquid crystal projector has been described. It can also be applied.
[0044]
【The invention's effect】
As described above, according to the present invention, it is possible to reduce the streak-like noise that occurs when the surface unevenness correction of the liquid crystal panel is performed, and to display a visually high-quality image.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the overall configuration of a surface unevenness correction apparatus in a liquid crystal projector according to an embodiment of the present invention.
FIG. 2 is a circuit diagram showing a surface unevenness correction apparatus according to an embodiment of the present invention.
FIG. 3 is an explanatory diagram illustrating an operation for correcting surface unevenness according to an embodiment of the present invention.
FIG. 4 is a flowchart illustrating an operation for correcting surface unevenness according to an embodiment of the present invention.
FIG. 5 is an explanatory diagram for explaining an operation for correcting surface unevenness according to another embodiment of the present invention.
FIG. 6 is a flowchart illustrating an operation for correcting surface unevenness according to another embodiment of the present invention.
FIG. 7 is an explanatory diagram illustrating a conventional surface unevenness correction operation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Liquid crystal projector 12 ... Optical box 13 ... Light source 14 ... Projection lens 15 ... Liquid crystal panel 16 ... Video signal processing circuit 17 ... Signal source 21 ... Screen 31 ... Camera 41 ... Correction apparatus 42 ... A / D conversion circuit 43 ... Clock generation Circuit 44 ... Point data extraction circuit 45 ... Correction data calculation circuit 46 ... Memory 47 ... D / A conversion circuit 48 ... Control circuit

Claims (8)

A surface unevenness correction device for a display panel constituted by a plurality of pixels arranged in a horizontal direction and a vertical direction,
Input means for capturing video displayed on the display panel as image data;
A plurality of correction points that are divided in advance are set on the display surface of the display panel, and correction data for correcting the surface unevenness of the pixel corresponding to each correction point is generated using the image data, and a plurality of adjacent correction points are generated. When the correction data of the correction points are regularly arranged with a preset difference, correction data obtained by changing the correction data values of the plurality of correction points in the arrangement direction by the difference at a predetermined interval Correction data generating means for generating
In order to perform surface unevenness correction on the intermediate pixels located between the plurality of correction points, complement processing is performed using correction data of correction points adjacent to each other, and complementary data for correcting surface unevenness of the intermediate pixels is generated. Interpolation data generating means for
A surface unevenness correction apparatus comprising: output data for outputting a surface unevenness correction signal to the display panel using the correction data from the correction data generation means and the interpolation data from the interpolation data generation means. When the correction data of a plurality of adjacent correction points are regularly arranged with a difference of 1 LSB, the correction data generating means sets the correction data values of the plurality of correction points in the arrangement direction at predetermined intervals. 2. The surface unevenness correcting apparatus according to claim 1, wherein the surface unevenness correcting device is changed by the amount corresponding to 1LSB. When the correction data of a plurality of adjacent correction points are regularly arranged with a difference of 1LSB, the correction data generating means sets the correction data values of the correction points in the arrangement direction every other correction data value. 3. The surface unevenness correcting apparatus according to claim 2, wherein the surface unevenness correcting apparatus is changed by an amount corresponding to the amount. A surface unevenness correction device for a display panel constituted by a plurality of pixels arranged in a horizontal direction and a vertical direction,
Input means for capturing video displayed on the display panel as image data;
A plurality of correction points that are divided in advance are set on the display surface of the display panel, and correction data for correcting the surface unevenness of the pixel corresponding to each correction point is generated using the image data, and a plurality of adjacent correction points are generated. When the correction data of the correction points are regularly arranged with a preset difference, the correction data values of a plurality of correction points in adjacent alignment directions are changed by the difference in a predetermined field unit. Correction data generating means for generating correction data;
In order to perform surface unevenness correction on the intermediate pixels located between the plurality of correction points, complement processing is performed using correction data of correction points adjacent to each other, and complementary data for correcting surface unevenness of the intermediate pixels is generated. Interpolation data generating means for
A surface unevenness correction apparatus comprising: output data for outputting a surface unevenness correction signal to the display panel using the correction data from the correction data generation means and the interpolation data from the interpolation data generation means. When the correction data of the plurality of adjacent correction points are regularly arranged with a difference of 1LSB, the correction data generating means sets the correction data values of the plurality of correction points in the arrangement direction in predetermined field units. 5. The surface unevenness correcting device according to claim 4, wherein the surface unevenness correcting device is changed for each 1 LSB. When the correction data of a plurality of adjacent correction points are regularly arranged with a difference of 1LSB, the correction data generating means sets the correction data values of the correction points in the arrangement direction in the 1LSB every other field. 5. The surface unevenness correcting device according to claim 4, wherein the surface unevenness correcting device is changed by an amount corresponding to the amount. A method for correcting surface unevenness of a display panel composed of a plurality of pixels arranged in a horizontal direction and a vertical direction,
Measuring the luminance level of the correction point set in advance divided into a plurality on the display surface of the display panel;
Correction data for correcting the brightness level of each correction point so as to approach a reference value is generated, and correction data of a plurality of adjacent correction points are regularly arranged with a preset difference. In this case, a correction data generation step for generating correction data in which correction data values of a plurality of correction points in the arrangement direction are changed by the difference at predetermined intervals;
An interpolation step of performing interpolation processing using correction data of adjacent correction points to generate interpolation data in order to perform surface unevenness correction on intermediate pixels located between the plurality of correction points;
A method for correcting surface unevenness, comprising: correcting the luminance level of the display panel using the correction data generated in the correction data generation step and the interpolation data generated in the interpolation step. A method for correcting surface unevenness of a display panel composed of a plurality of pixels arranged in a horizontal direction and a vertical direction,
Measuring the luminance level of the correction point set in advance divided into a plurality on the display surface of the display panel;
Correction data for correcting the brightness level of each correction point so as to approach a reference value is generated, and correction data of a plurality of adjacent correction points are regularly arranged with a preset difference. In this case, a correction data generation step of generating correction data in which correction data values of a plurality of correction points in the arrangement direction are changed by the difference in a predetermined field unit;
An interpolation step of performing interpolation processing using correction data of adjacent correction points to generate interpolation data in order to perform surface unevenness correction on intermediate pixels located between the plurality of correction points;
A method for correcting surface unevenness, comprising: correcting the luminance level of the display panel using the correction data generated in the correction data generation step and the interpolation data generated in the interpolation step.

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