JP2006235325A - Method for correcting image persistence phenomenon, spontaneous light emitting device, device and program for correcting image persistence phenomenon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for correction processing of an image persistence phenomenon generated in a spontaneous light emitting device in which a plurality of spontaneous light emitting elements are arranged like a matrix. <P>SOLUTION: Grayscale data is partitioned by every block area to which corresponding pixels belong to calculate information indicating a degree of variation of distribution of grayscale data values. Next, an auxiliary correction quantity by every block area is determined according to the degree of variation. A standard correction quantity to be sequentially determined from accumulated difference of deterioration level is corrected based on the auxiliary correction quantity to determine the final correction quantity. Then, a display signal before image persistence correction is corrected based on the final correction quantity. Thus, the image persistence phenomenon of the spontaneous light emitting device is corrected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  One embodiment of the present invention relates to a method for correcting a burn-in phenomenon that occurs in a self-luminous device. One embodiment of the present invention relates to a burn-in phenomenon correcting device and a self-light-emitting device equipped with the same. One embodiment of the present invention relates to a program for causing a computer mounted on a self-luminous device to execute a burn-in correction function.

Flat panel displays are widely used in products such as computer displays, portable terminals, and televisions. Currently, liquid crystal display panels are mainly used, but the narrow viewing angle and slow response speed continue to be pointed out.
On the other hand, an organic EL display formed of a self-luminous element can overcome the above-mentioned problems of viewing angle and responsiveness, and can achieve a thin form, high brightness, and high contrast that do not require a backlight. Therefore, it is expected as a next-generation display device that replaces the liquid crystal display.

By the way, it is generally known that organic EL elements and other self-light-emitting elements have a property of deteriorating depending on the light emission amount and the light emission time.
On the other hand, the content of the image displayed on the display is not uniform. For this reason, the deterioration of the self-luminous element is likely to proceed partially. For example, the self-light-emitting element in the time display area (fixed display area) progresses more rapidly than the self-light-emitting elements in other display areas (moving image display areas).
The luminance of the self-luminous element that has deteriorated is relatively lowered as compared with the luminance of other display areas. In general, this phenomenon is called “burn-in”. Hereinafter, partial deterioration of the self-luminous element is referred to as “burn-in”.

At present, various methods are being studied for improving the “burn-in” phenomenon. Some of them are listed below.
In this document, input data for each pixel constituting the display panel is integrated for each pixel at a constant period, and the integrated value of each pixel is subtracted from the maximum value of each pixel. A method for setting the correction amount is disclosed. Further, a method is disclosed in which the display characteristics of each pixel are made uniform by emitting each pixel with a constant luminance for a time proportional to the amount of correction in a non-use state.

In this document, display data and display time are stored only when a still image is displayed, and the difference ΔY between the display data and the maximum luminance and the time T when the still image is displayed are integrated. A method of setting the amount ΔY · T as correction data is disclosed. Also, this document discloses a method for correcting a burn-in phenomenon by executing a display for correction only when the lid is closed or not used.

However, since the existing correction method prioritizes correction of the burn-in phenomenon, there is a possibility that the image is greatly changed. That is, as a result, there is a possibility that the image quality is significantly deteriorated.
However, if the correction amount is kept small considering the influence on the image quality, it may take a long time to correct the difference in deterioration amount, or the correction itself may be impossible because the correction is not in time.

The inventors propose the following technique as a method for correcting a burn-in phenomenon that occurs in a self-light-emitting device in which a plurality of self-light-emitting elements are arranged in a matrix.
That is, (1) processing for dividing gradation data into block areas to which corresponding pixels belong, and (2) processing for calculating information indicating the degree of variation in distribution of gradation data values associated with each block area. And (3) a process for determining an auxiliary correction amount for each block area according to the degree of variation in the distribution of gradation data values, and (4) based on the display signal after the burn-in correction, for all pixels to be compared. A process for obtaining a deterioration amount difference, (5) a process for cumulatively adding the deterioration amount difference for each pixel, calculating a cumulative deterioration amount difference generated for each pixel, and (6) a burn-in correction based on the cumulative deterioration amount difference Processing for sequentially determining the standard correction amount to be used in the process, (7) processing for correcting the standard correction amount with the corresponding auxiliary correction amount and determining the final correction amount, and (8) burn-in correction based on the final correction amount Previous display signal To propose a technical solution and a process of positive to.

In general, a block area where the degree of variation in the distribution of gradation data values is large has a characteristic that it is difficult to visually recognize a decrease in image quality even if the luminance change is somewhat large. On the other hand, the block area where the degree of variation in the distribution of gradation data values is small has the characteristic that image quality deterioration is easily recognized even with a minute luminance change.
These technical methods can be applied not only to the self-luminous device itself, but also to various electronic devices that process image signals output to the output device. Further, these technical methods can be realized not only as hardware but also as software. Of course, part of the processing can be executed as hardware, and the remaining processing can be executed as software.
Incidentally, the self-luminous device includes an organic EL (electroluminescence) panel, a PDP (plasma display panel), a CRT (cathode ray tube), an FED (field emission display) panel, an LED panel, and a projector.

By correcting the correction amount generated primarily according to the deterioration amount according to the variation in the distribution of the gradation data values, it is possible to execute the burn-in correction in a state in which the deterioration in image quality is not recognized as much as possible.
In addition, this function can reduce the number or rate of such correction even when correction accompanied by a reduction in image quality is necessary to reduce the deterioration amount difference.

Hereinafter, an embodiment example of a burn-in phenomenon correction technique that employs the technical technique according to the invention will be described.
In addition, the well-known or well-known technique of the said technical field is applied to the part which is not illustrated or described in particular in this specification.
The embodiment described below is one embodiment of the present invention and is not limited thereto.

(A) Form example of burn-in phenomenon correction apparatus (A-1) Form example 1
(A) Device Configuration FIG. 1 shows an example of a burn-in phenomenon correcting device. Hereinafter, the burn-in phenomenon correction device is referred to as a “correction device”.
In the case of this embodiment, the correction device 1 is arranged for each pixel that emits light of the same color. The emission color generally refers to three colors of red, blue, and green. However, when complementary colors other than the three colors are used, they are arranged for each color.
The correction device 1 includes a deterioration amount difference calculation unit 3, a cumulative deterioration amount difference accumulation unit 5, a standard correction amount determination unit 7, a display data regionization unit 9, a gradation variation calculation unit 11, an auxiliary correction amount determination unit 13, and a final correction amount determination unit 7. The correction amount determination unit 15 and the luminance deterioration correction unit 17 are main components.

The deterioration amount difference calculation unit 3 is a processing device that calculates the deterioration amount difference between each pixel and the comparison target pixel based on the gradation data after the correction process. Here, any method including a known method can be applied to the method of calculating the deterioration amount difference. This is because the method proposed by the inventors is characterized by a correction portion of the standard correction amount.
As a calculation example, the following method is illustrated. For example, a method of calculating the difference between the gradation data value of each pixel and the gradation data value of the comparison target pixel can be applied. In addition, for example, when a proportional relationship is not established between the gradation data and the degree of progress of deterioration, a method of calculating a deterioration amount difference using a conversion coefficient reflecting an actual measurement result can be applied. The inventors define this conversion coefficient by the concept of “deterioration rate”.

The inventors define the “deterioration rate” as the rate of decrease in light emission luminance when the self-luminous element continuously emits light with a certain gradation data.
FIG. 2 shows an example of a conversion table showing the correspondence between the gradation data and the deterioration rate. In this case, there is a method of calculating the deterioration amount difference as a difference between the deterioration rate of each pixel and the deterioration rate of the comparison target pixel. Further, the deterioration amount difference can also be calculated as a difference between values obtained by multiplying the deterioration rate R by the light emission period T.
By the way, several methods can be considered for the comparison target pixel used for calculating the deterioration amount difference. Usually, an optimum pixel is designated according to the correction method used for determining the standard correction amount.
For example, a pixel with the most deteriorated luminance, a pixel with the least delayed luminance, a pixel at the center of the screen, a pixel corresponding to fixed display, and the like are designated. These are actual pixels. Further, for example, a pixel or the like that gives an average luminance value is designated. These are pixels that are virtually determined.

The accumulated deterioration amount difference accumulation unit 5 is a memory that continuously accumulates the deterioration amount differences updated for each frame and stores the accumulation result. Here, the cumulative deterioration amount difference of the pixels whose deterioration has progressed with respect to the comparison target pixel is represented by a positive value. Also, the cumulative deterioration amount difference of the pixels whose deterioration is delayed with respect to the comparison target pixel is represented by a negative value.
The standard correction amount determination unit 7 is a processing device that determines a standard correction amount corresponding to each pixel based on the deterioration amount difference read from the cumulative deterioration amount difference accumulation unit 5. Basically, the standard correction amount is determined in a direction that eliminates the deterioration amount difference corresponding to each pixel (that is, a direction to make it zero).
For example, when the accumulated deterioration amount difference is a positive value, the standard correction amount is determined to be a negative value. Further, for example, when the accumulated deterioration amount difference is a negative value, the standard correction amount is determined to be a positive value.

Here, the specific determination method of the standard correction amount is arbitrary. This is because the technical method according to the invention is characterized by the correction of the determined correction amount, and the standard correction amount determination method has no effect.
However, in this embodiment, the following constraint condition is provided for the maximum value of the standard correction amount to be generated. In other words, in the pattern screen that is composed of the same gradation data value, the maximum value of the absolute value of the standard correction amount is such that when the gradation data value is changed only for a certain area, the change is not easily visible. Limit.
This means a condition in which a deterioration in image quality is not easily seen no matter what image burn-in correction is performed.

The display data area converting unit 9 is a processing device that divides gradation data before correction processing into areas for each block area to which the corresponding pixel belongs. FIG. 3 shows an example of area formation for each block area. The block area shown in FIG. 3 shows a case where the block area is composed of a total of 9 pixels of 3 pixels (hereinafter referred to as 3 × 3) in each of the horizontal direction and the vertical direction. Note that these nine pixels are all nine pixels for pixels that emit light of the same color.
FIG. 3A corresponds to the pixel array before regionization, and FIG. 3B corresponds to the pixel array after regionization. In FIG. 3B, the block area is surrounded by a bold line.
The gradation data classified by the regionalization processing is output to the gradation variation calculation unit 11 in block area units.

The gradation variation calculation unit 11 is a processing device that calculates information indicating the degree of variation in the distribution of gradation data values for each block area. For example, it is calculated as a variance value or a standard deviation value. 4A and 4B show calculation examples. FIG. 4A shows an example of distribution of gradation data values corresponding to each block area. FIG. 4B is an example of standard deviation values calculated for each block area. For example, the standard deviation value of the block area in the upper left corner in the figure is “45”, and the standard deviation value of the block area on the right is “102”.
The auxiliary correction amount determination unit 13 is a processing device that inputs information indicating the degree of variation in the distribution of gradation data values calculated for each block area and determines the auxiliary correction amount for each block area. In the case of this embodiment, the auxiliary correction amount is given by a correction magnification with respect to the standard correction amount.

The auxiliary correction amount determination unit 13 has a table for converting standard deviation values into correction magnifications. FIG. 5 shows an example table. In the table of FIG. 5, the standard deviation values are classified into a plurality of sections, and a single correction magnification is assigned to each section.
In the case of this example, a smaller correction magnification is set for a section to which a smaller standard deviation value belongs. A small standard deviation value means that there is little change in the gradation data value. That is, it means that a monotonous image pattern with little gradation change is displayed. Such a block area has a characteristic that variations in the correction amount are easily perceived. Therefore, the correction magnification of the section with the standard deviation value “0” to “25” is set to “1”.
Therefore, if the correction magnification is “1”, the standard correction amount is used as it is as the final correction amount.

On the other hand, a large standard deviation value means that there are many changes in gradation data values. That is, it means that an image pattern with a large gradation change is displayed. Such a block area has a characteristic that variations in the correction amount are difficult to perceive. Therefore, the correction magnification of the section whose standard deviation value is “100” or more is set to “5”.
Therefore, if the correction magnification is “5”, a value obtained by multiplying the standard correction amount by 5 is used as the final correction amount.
FIG. 4C shows an output example of the auxiliary correction amount using the table shown in FIG. It can be seen that the auxiliary correction amount “2” is associated with the block area having the standard deviation value “45” described above. It can also be seen that the auxiliary correction amount “5” is associated with the block area of the standard correction amount “102”.

The final correction amount determination unit 15 is a processing device that corrects the standard correction amount with the corresponding auxiliary correction amount and determines the final correction amount. In this example, the final correction amount determination unit 15 multiplies the standard correction amount by the auxiliary correction amount and outputs the multiplication result as the final correction amount.
The luminance deterioration correction unit 17 is a processing device that corrects gradation data before correction based on the final correction amount. In the case of this example, the luminance deterioration correction unit 17 executes a process of adding the final correction amount (positive value or negative value) calculated for the block area to which the pixel belongs to the gradation data corresponding to each pixel.
The corrected gradation data is output to a self-light emitting panel module (not shown).

(B) Correction Processing Operation Next, a series of correction operations by the correction device will be described.
FIG. 6 shows an operation example until the final correction amount is determined when 3 × 3 pixels are used as one block area.
FIG. 6A shows an example of the accumulated deterioration amount difference of each pixel with respect to the comparison target pixel at a certain point in time. With respect to the comparison pixel, a positive value is assigned to the cumulative deterioration amount difference of the pixel that has been deteriorated, and a negative value is assigned to the cumulative deterioration amount difference of the pixel that has been delayed.
FIG. 6B is an example of a standard correction value set from each cumulative deterioration amount difference. In the case of this example, the maximum value of the number of gradation steps giving the standard correction value is limited to 4 steps.

As described above, the number of gradation steps is the maximum value of an allowable range that is not easily visually recognized when the gradation data value is changed only in a certain region when all the gradation data values are the same.
This value reflects an acceptable level for image quality degradation. Therefore, there is a possibility that the actual correction operation may be subjectively evaluated or may vary depending on a difference in the way of thinking about individual panel image quality.
In the case of FIG. 6B, for a pixel having a cumulative deterioration amount difference of “2” or less, a value obtained by changing the sign of the cumulative deterioration amount difference is used as it is as a standard correction amount. On the other hand, for a pixel having a cumulative deterioration amount difference of “2” or more, a value “2” obtained by exchanging the sign of the cumulative deterioration amount difference is used as the standard correction amount.

FIG. 6C is an example of an auxiliary correction amount in block area units corresponding to each pixel.
FIG. 6D shows the result of multiplying the auxiliary correction amount by the standard correction amount. A final correction value having a larger correction amount is given to a region where the degree of variation in the distribution of gradation data in the block area is larger.
For example, the final correction amount corresponding to the pixel with the standard correction amount “−2” and the auxiliary correction amount “2” is calculated as “−4”. Similarly, the final correction amount corresponding to the pixel having the standard correction amount “2” and the auxiliary correction amount “5” is calculated as “10”.
FIG. 7 shows a correction operation in the luminance deterioration correction unit 17. The luminance deterioration correction unit 17 represents a state in which the final correction amount (FIG. 7B) is added to the pre-correction gradation data (FIG. 7A).

FIG. 7C shows the gradation data value after correction. As shown in FIG. 7, the correction amount is large in the block area where the variation of the gradation data value in the block area is relatively large, and the correction amount is small in the block area where the variation of the gradation data value in the block area is small. I understand.
This means that the correction of the deterioration amount difference is positively executed in the block area where the variation of the gradation data value is large. On the other hand, in the block area where the variation of the gradation data value is small, it means that the correction of the deterioration amount is executed in a range where the gradation change is not visually recognized.
As a result, it is possible to generate a gradation data value (display signal) that is corrected so as to reduce the difference in deterioration amount between pixels within a range in which the deterioration in image quality of the original image is not visually recognized.

(C) Effects of Embodiments With this correction apparatus 1, while the variation width of the standard correction amount is kept small, the variation in the gradation data value distribution is large, and the gradation change due to burn-in correction is difficult to be visually recognized. For these pixels, the correction amount can be positively increased.
As a result, it is possible to achieve both the effect of correcting the burn-in phenomenon and the image quality after correction.
In the case of this embodiment, the standard correction amount is calculated using the display signal after the burn-in correction processing, so that an accurate deterioration amount difference is included in a state where all the information of the display signal corrected by the auxiliary correction amount is included. Can be calculated. Note that in the case of a method of estimating the deterioration amount difference based on the display signal before the burn-in correction, a calculation process for reflecting the correction by the auxiliary correction amount on the deterioration amount difference is necessary. Therefore, the correction device 1 is a highly effective device configuration in that the circuit scale and the calculation load can be reduced.

(A-2) Embodiment 2
FIG. 8 shows another example of the correction apparatus. In FIG. 8, parts corresponding to those in FIG. The basic configuration and processing operation of the correction device 21 are the same as those in the first embodiment.
The difference is that in the case of the correction device 21, the display signal used for calculating the auxiliary correction amount is different from the display signal used for calculating the standard correction amount.
FIG. 8 shows, as an example, a case where the display signal to be corrected by the luminance degradation correction unit 17 is given by the drive current applied to the self-light emitting element.
However, the display signal to be corrected is not limited to the drive current as long as it is a signal related to the drive condition of the self-light emitting element. For example, a drive voltage value applied between the anode and cathode of the self-luminous element may be used.
Even when this correction device 21 is used, the same effect as in the first embodiment can be realized.

(A-3) Embodiment 3
In this embodiment, a case will be described in which human visual characteristics with respect to image motion are combined with the technique shown in Embodiment 1. That is, a method for further optimizing the final correction amount will be described using the fact that the gradation change in the moving image area is not easily recognized with respect to the gradation change in the still image area.
(A) Device Configuration FIG. 9 shows another example of the correction device. In FIG. 9, parts corresponding to those in FIG. As shown in FIG. 9, the basic configuration of the correction device 31 is the same as that of the first embodiment.
Among these, there are two components that are unique to the correction device 31, that is, the moving image still image determination unit 33 and the luminance deterioration correction unit 35.

The moving image still image determination unit 33 is a processing device that determines a moving image region and a still image region for each pixel. FIG. 10 shows a configuration example of the moving image still image determination unit 33. The moving image still image determination unit 33 includes a current frame memory 33A, a previous frame memory 33B, and a comparison determination unit 33C.
The current frame memory 33A is for storing gradation data of the latest frame, and the previous frame memory 33B is for storing gradation data of one frame before the current frame.
The comparison determination unit 33C compares the gradation data stored in the current frame with the gradation data stored in the previous frame for the same pixel, and determines whether the area is a moving image area or a still image area based on the comparison result. Processing device.

In the case of this example, the comparison / determination unit 33C determines that the pixel whose gradation data matches between frames as a still image area, and determines the pixel whose gradation data does not match between frames as a moving image area.
The comparison determination unit 33C sets the determination output of the pixel determined as the still image region to “0”, and sets the determination output of the pixel determined as the moving image region to “1”.
FIG. 11 shows an operation example of the comparison determination unit 33C. FIG. 11A shows the gradation data of the current frame, and FIG. 11B shows the gradation data of the previous frame. FIG. 11C shows an output example of motion determination data reflecting the comparison result between the current frame and the previous frame.

For example, in the case of FIGS. 11A and 11B, the gradation data of the pixel located at the upper left corner of the frame area is “55” in both the current frame and the previous frame. Therefore, this pixel is determined as a still image region, and the motion determination data is “0” as shown in FIG.
Further, for example, in the case of FIGS. 11A and 11B, the gradation data of the pixel in the first column from the left end of the frame area and the second row from the top is “111” for the current frame. The frame is “22”. Therefore, this pixel is determined as a moving image region, and the motion determination data is “1” as shown in FIG. The same applies to other pixels.
This determination result is given from the comparison determination unit 33C to the luminance deterioration correction unit 35.

The luminance deterioration correction unit 35 is a processing device that corrects the final correction amount given to each pixel according to the motion determination result of each pixel, and executes correction processing for correcting the gradation data based on the corrected correction amount. is there. In other words, the luminance degradation correction unit 35 has two functions: a function that adaptively corrects the final correction amount, and a function that corrects luminance degradation based on the corrected correction amount.
FIG. 12 shows a configuration example of the luminance deterioration correction unit 35. The luminance deterioration correction unit 35 includes a motion determination data memory 35A, a correction data memory 35B, a correction amount correction unit 35C, and a correction execution unit 35D.
Among these, the motion determination data memory 35 </ b> A is a memory that stores motion determination data (0 or 1) given from the moving image still image determination unit 33. The correction data memory 33 </ b> B is a memory that stores the final correction amount given from the final correction amount determination unit 15.

The correction amount correcting unit 33C is a processing device that adaptively corrects the final correction amount according to the motion determination data. Although there are several methods for correcting the final correction amount, three typical examples are shown in FIG.
For example, when the correction method shown in FIG. 13A is adopted, the final correction amount corresponding to the pixel determined as the moving image area is corrected so as to increase in the correction direction, and is determined as the still image area. The final correction amount corresponding to the selected pixel is output without being corrected. That is, only the moving image area is corrected so that the absolute value of the final correction amount is further increased.
This means that the correction effect is positively accelerated in a moving image region where it is difficult to perceive deterioration in image quality.

Further, for example, when the correction method shown in FIG. 13B is adopted, the final correction amount corresponding to the pixel determined as the moving image area is corrected so as to increase in the correction direction, and is determined as the still image area. The final correction amount corresponding to each pixel is corrected so as to decrease with respect to the correction direction. That is, the final correction amount of the moving image area is corrected so that the absolute value becomes large, and the final correction amount of the still image area is corrected so that the absolute value becomes small.
This means that the correction effect is positively accelerated in a moving image region where it is difficult to perceive deterioration in image quality. On the other hand, in a still image area where deterioration of image quality is easily perceived, it means that the correction effect is positively decelerated. That is, an image close to the original image is displayed.
Of course, the correction effect on the still image area is reduced, but the burn-in correction effect is positively promoted at the opportunity of the same pixel becoming the moving image area. Therefore, the burn-in phenomenon becomes difficult to perceive as time passes.

In addition, the correction method shown in FIG. 13C can also be adopted. In this case, the final correction amount corresponding to the pixel determined as the moving image region is corrected so as to increase in the correction direction, but the final correction amount corresponding to the pixel determined as the still image region is 0 (zero). ) Is corrected. That is, although the final correction amount of the moving image area is corrected so that the absolute value becomes large, the correction is executed so that the correction process is not executed in the still image area.
This means that the correction effect is accelerated in the moving image area where the deterioration of the image quality is hardly perceived, while the original image is displayed as it is in the still image area where the deterioration of the image quality is easily perceived. Naturally, the burn-in in the still image area remains as it is, but the burn-in correction effect is positively promoted when the same pixel becomes the moving image area. Therefore, the burn-in phenomenon becomes difficult to perceive as time passes.

By the way, the correction amount used when the final correction amount is increased or decreased may be a fixed value for all the pixels, or may be changed according to the final correction amount. For example, as a method of fixing the correction amount, there is a method of uniformly setting 10 gradations as the correction amount. For example, as a method of changing the correction amount in accordance with the final correction amount, there is a method of giving a few percent of the final correction amount. However, it is also permitted to give the correction amount within a range of 1 or more depending on the use situation. How to set the correction amount largely depends on human visual characteristics, and therefore an optimal amount may be selected according to the experimental result.
In the case of this embodiment, the same correction method is applied regardless of the difference in emission color, but the correction method and the correction amount can be given for each emission color.

The correction execution unit 35D is a processing device that executes correction processing of gradation data based on the corrected final correction amount given from the correction amount correction unit 33C. That is, the correction execution unit 33D adds the final correction amount having a code corresponding to the correction direction to the gradation data of each pixel, and corrects the gradation data. That is, when the luminance deterioration is promoted, the corrected final correction amount is added to the gradation data, and when the luminance deterioration is delayed, the corrected final correction amount is subtracted from the gradation data.
The corrected gradation data is output from the correction execution unit 33D to a subsequent circuit (not shown), and finally controls the light emitting operation of the light emitting element corresponding to each pixel.

As a result, the correction amount corresponding to the pixel in the block area where the variation in the gradation data value is large and is also the moving image region is corrected to a value larger than the final correction amount.
Further, for example, the correction amount corresponding to the pixel in the block area where the variation of the gradation data value is large and is also the still image region is corrected to the final correction amount or less.
Further, for example, the correction amount corresponding to the pixel in the block area where the variation in the gradation data value is small and at the same time the moving image region is corrected to the final correction amount or less.
Further, for example, the correction amount corresponding to the pixel in the block area where the variation in the gradation data value is small and at the same time also the still image region is corrected to the final correction amount or less.

(B) Effects of Embodiments By using this correction device 31, the burn-in correction amount can be adjusted not only according to the degree of variation in the distribution of gradation data values but also depending on whether each pixel is a moving image region or a still image region. Further, it is possible to simultaneously realize the burn-in correction and the maintenance of the visually recognized image quality.
That is, the reduction width of the deterioration amount difference can be increased as compared with the first embodiment for the pixel in which the deterioration of the image quality is not easily visually recognized, and the reduction in the image quality is more easily recognized than that in the first embodiment for the pixel. The reduction width of the deterioration amount difference can be reduced.

(A-4) Embodiment 4
In this embodiment, another example in which human visual characteristics with respect to image movement are combined with the technique shown in Embodiment 1 will be described. In other words, a case will be described in which the final correction amount is further optimized by utilizing the fact that the gradation change in the bright region is less visible with respect to the gradation change in the dark region.
(A) Device Configuration FIG. 14 shows another example of the correction device. In FIG. 14, parts corresponding to those in FIG. As shown in FIG. 14, the basic configuration of the correction device 41 is the same as that of the first embodiment.
Among these, there are two components that are unique to the correction device 41, that is, a brightness determination unit 43 and a luminance deterioration correction unit 45.

The brightness determination unit 43 is a processing device that monitors gradation data input for each pixel and determines the brightness for each pixel.
The brightness determination unit 43 has a determination threshold value to be compared with the gradation data, and outputs brightness determination data according to the gradation data. Here, the brightness determination data includes a case where a bright region or a dark region is given, and a case where a correction coefficient corresponding to the brightness is given.
FIG. 15 is an example of a determination threshold value and brightness determination data for assigning gradation data to either a bright region or a dark region. In FIG. 15, the intermediate gradation is used as the determination threshold value, but a higher value may be used as the determination threshold value. These are set in consideration of human visual characteristics. However, depending on the screen, a value smaller than the intermediate gradation may be set as the determination threshold.

FIG. 16 is an example of determination threshold values and brightness determination data for assigning gradation data to correction coefficients A0 to A255. In FIG. 16, the determination threshold is set in increments of one gradation, but the determination threshold may be set in increments of a plurality of gradations. Here, it is assumed that the relationship of Ai + 1 ≧ Ai (i = 0 to 244) is established in the correction coefficient. The correction coefficient may be a mixture of positive and negative values with a certain determination threshold as a boundary. That is, the correction coefficient for the bright area is a positive value, and the correction coefficient for the dark area is a negative value.
The luminance degradation correction unit 45 corrects the final correction amount given to each pixel according to the motion determination result and the brightness determination result, and executes correction processing for correcting the gradation data based on the corrected final correction amount. It is a processing device. The luminance deterioration correction unit 45 also has two functions: a function of adaptively correcting the final correction amount and a function of correcting luminance deterioration based on the corrected final correction amount.

FIG. 17 shows a configuration example of the luminance deterioration correction unit 45. The luminance deterioration correction unit 45 includes a brightness determination data memory 45A, a correction data memory 45B, a correction amount correction unit 45C, and a correction execution unit 45D.
Among these, the brightness determination data memory 45 </ b> A is a memory for storing brightness determination data given from the brightness determination unit 43. The correction data memory 45B is a memory for storing the final correction amount given from the final correction amount determination unit 15.

The correction amount correction unit 45C is a processing device that adaptively corrects the final correction amount according to the brightness determination data. There are several methods for correcting the final correction amount.
For example, FIG. 18 shows an example of a correction method in the case where two pieces of information of a bright area and a dark area are given as brightness determination data.
Among these, when the correction method shown in FIG. 18A is adopted, the final correction amount corresponding to the pixel determined as the bright region is corrected so as to increase in the correction direction, and is determined as the dark region. The final correction amount corresponding to the pixel is output without being corrected. That is, only the bright region is corrected so that the absolute value of the final correction amount is further increased.
This means that the correction effect is positively accelerated in a bright region where deterioration in image quality is difficult to perceive.

Further, for example, when the correction method illustrated in FIG. 18B is adopted, the final correction amount corresponding to the pixel determined as the bright region is corrected so as to increase in the correction direction, and the pixel determined as the dark region The final correction amount corresponding to is corrected so as to decrease with respect to the correction direction. That is, the final correction amount in the bright region is corrected so that the absolute value becomes large, and the final correction amount in the dark region is corrected so that the absolute value becomes small.
This means that the correction effect is positively accelerated in a bright region where deterioration in image quality is difficult to perceive. On the other hand, in a dark region where deterioration in image quality is easily perceived, it means that the correction effect is actively decelerated. That is, an image close to the original image is displayed.
Of course, although the correction effect on the dark region is reduced, the burn-in correction effect is positively promoted on the occasion that the same pixel becomes a bright region. Therefore, the burn-in phenomenon becomes difficult to perceive as time passes.

In addition, the correction method shown in FIG. 18C can also be adopted. In this case, the final correction amount corresponding to the pixel determined as the bright region is corrected so as to increase in the correction direction, but the final correction amount corresponding to the pixel determined as the dark region is 0 (zero). Will be corrected. That is, the final correction amount in the bright area is corrected so that the absolute value becomes large, but the correction process is performed so that the correction process is not executed in the dark area.
This means that the correction effect is accelerated in the bright area where the deterioration of the image quality is difficult to perceive, while the original image is displayed as it is in the dark area where the deterioration of the image quality is easily perceived. Naturally, the burn-in in the dark region remains as it is, but the burn-in correction effect is positively promoted when the same pixel becomes a bright region. Therefore, the burn-in phenomenon becomes difficult to perceive as time passes.

Note that when the brightness determination data is given by the correction coefficients A0 to A255, the correction method shown in FIG. 19 can be applied.
Among these, when the correction method shown in FIG. 19A is adopted, the correction amount corresponding to the pixel determined to be a bright region is calculated as the final correction amount * At (t is any numerical value from 0 to 255). Is done. On the other hand, the correction amount corresponding to the pixel determined to be a dark region is controlled to zero. That is, for the pixel corresponding to the dark region, the final correction amount is used with no correction.
On the other hand, when the correction method shown in FIG. 19B is adopted, the correction amount corresponding to the pixel determined to be a bright region is calculated as the final correction amount * At (At is a positive value). On the other hand, the correction amount corresponding to the pixel determined to be a dark region is calculated as the final correction amount * At (At is a negative value). That is, the final correction amount is corrected to a larger value in the bright region, and is corrected to a value smaller than the final correction amount in the dark region.

The correction execution unit 45D is a processing device that executes gradation data correction processing based on the final correction amount corrected by the correction amount correction unit 45C. In other words, the correction execution unit 45D corrects the gradation data by adding a correction amount having a sign corresponding to the correction direction to the gradation data of each pixel. The corrected gradation data is finally used to control the light emission of the light emitting element corresponding to each pixel.
As a result, the correction amount corresponding to the pixel in the block area where the variation of the gradation data value is large and at the same time is also the bright region is corrected to a value larger than the final correction amount.
Further, for example, the correction amount corresponding to the pixel in the block area where the variation in the gradation data value is large and at the same time the dark region is corrected to the final correction amount or less.
Further, for example, the correction amount corresponding to the pixel in the block area where the variation of the gradation data value is small and at the same time the bright region is corrected to the final correction amount or less.
Further, for example, the correction amount corresponding to the pixel in the block area where the variation of the gradation data value is small and also the dark region is corrected to the final correction amount or less.

(B) Effects of Embodiments By using this correction device 41, the burn-in correction amount can be adjusted depending on whether each pixel is a bright region or a dark region as well as the degree of variation in the distribution of gradation data values. The promotion of correction and the maintenance of visually recognized image quality can be realized at the same time.
That is, the reduction width of the deterioration amount difference can be increased as compared with the first embodiment for the pixel in which the deterioration of the image quality is not easily visually recognized, and the reduction in the image quality is more easily recognized than that in the first embodiment for the pixel. The reduction width of the deterioration amount difference can be further reduced.

(D) Example of mounting on self-luminous device FIG. 20 shows an example of mounting the burn-in phenomenon correcting device on the self-luminous device.
The self-light-emitting device 51 has a burn-in phenomenon correction device 55 and a display device 57 mounted on a housing 53.
Here, the burn-in phenomenon correction device 55 corresponds to one of the above-described embodiments. The burn-in phenomenon correction device 55 receives an image signal generated at an external terminal or inside, and executes an input signal correction operation so that a deterioration amount difference does not occur between the correction target pixel and the reference pixel.

The display device 57 is assumed to be composed of a display device and its drive circuit. As the display device, an organic EL (electroluminescence) panel, a PDP (plasma display panel), an FED (field emission display) panel, an LED panel, or a CRT is used.
In the case of FIG. 20, the self-light-emitting device 51 is illustrated as having a burn-in phenomenon correction device 55 that is a processing device dedicated to correcting the burn-in phenomenon. However, when all the functions are executed in software. These functions are realized by a computer mounted on the self-luminous device.

(E) Mounting Example to Image Processing Device FIG. 21 shows a system example of the image processing device 63 in which the burn-in correction device 61 is mounted. The image processing device 63 is connected to the self-luminous display device 65 via a wired path or a wireless path.
In the case of this system example, the burn-in correction process is executed in the housing of the image processing apparatus 63. That is, the image signal output to the display device 65 is input to the burn-in correction circuit 61 arranged between the output interface and the burn-in correction process described above is executed.

  Examples of this type of image processing device 63 include a video camera, a digital camera, and other imaging devices (including not only a camera unit but also a device integrated with a recording device), a computer (including a server). Various information processing terminals (portable computers, mobile phones, portable game machines, electronic notebooks, etc.), various image playback devices (including home servers), image editing devices, and game machines can be applied. is there.

(F) Other Embodiments (a) In the above-described embodiments, the case where the standard correction amount is derived based on the display signal (gradation data) after the correction processing has been described.
However, the present invention can also be applied to a correction apparatus that calculates a standard correction amount based on a display signal before correction processing. However, in this case, since the standard correction amount is corrected by the auxiliary correction amount, a mechanism for reflecting the correction to the standard correction amount in the calculation of the standard correction amount may be installed.
(B) In the above-described embodiment, the case where the final correction amount is added to or subtracted from the display signal to be corrected has been described. However, the display signal may be corrected using other methods. For example, a method of increasing or decreasing the absolute value of the display signal by multiplying the display signal by the final correction amount may be employed.

(C) In the above-described embodiment, the block area is defined as a total of 9 pixels of 3 × 3 pixels.
However, the number of pixels constituting the block area is not limited to this. For example, it may be defined as a total of 25 pixels of 5 × 5 pixels. The block area does not have to be a square area, but may be a rectangular area.
(D) In the above-described embodiment, the case where the auxiliary correction amount is a natural number larger than 1 has been described.
However, the auxiliary correction amount may be a value smaller than 1. For example, it may be 0.5 or 0 (zero). When the auxiliary correction amount is 0.5, the final correction amount is determined as half the standard correction amount. This is effective for a pixel in which a gradation change is easily visible. Further, not only is the gradation change easily visible, but the auxiliary correction amount may be set to 0 when it is basically necessary to avoid a decrease in image quality.

(E) In the above-described embodiment, the standard deviation values are classified into four categories, and the auxiliary correction amount corresponding to each category is defined as “1”, “2”, “3”, “5”.
However, the number of standard deviation values may be smaller or larger than four. Also, other values can be used for the correction magnification to be associated.
(F) In the above-described embodiment, a case has been described in which each pixel is determined in the burn-in phenomenon correction device as to whether it is a moving image region or a still image region.
However, as the information about the moving image area or the still image area, a motion vector decoded by an image data decoding apparatus prepared separately from the burn-in phenomenon correction apparatus may be used.

FIG. 22 shows an example of this system. FIG. 22 shows a system example in which the image data decoded by the image data decoding device 71 and the motion vector are input to the burn-in phenomenon correction device.
The image data decoding device 71 employs a configuration in which the encoded image data is decoded by giving the motion vector decoded by the motion vector decoding unit 71A to the image data decoding processing unit 71B. Such a decoding mechanism is employed in various moving image processing technologies.

At present, the motion vector is basically used only for the decoding process of the image data. However, by giving this motion vector to the burn-in phenomenon correction device 73, the moving image still image determination unit described in the embodiment is not used. Both can achieve the same effect.
However, a function for classifying each pixel into a moving image area and a still image area based on a motion vector is necessary.
This system configuration can be mounted in the housing of the self-light-emitting device, or can be mounted in the housing of the image processing apparatus described above.

(G) In the above-described embodiment, the functional configuration of the burn-in phenomenon correction apparatus has been described. Needless to say, an equivalent function can be realized as hardware or software.
Further, not only all the functions constituting the burn-in phenomenon correcting apparatus are realized by hardware or software, but some of the functions can also be realized by using hardware or software. That is, a combination of hardware and software may be used.
(H) Various modifications can be considered for the above-described embodiments within the scope of the gist of the invention. Various modifications and application examples created based on the description of the present specification are also conceivable.

It is a figure which shows the example of a form of the burn-in phenomenon correction apparatus. It is a figure which shows the example of a conversion table holding the correspondence of a gradation value and a deterioration rate. It is a figure which shows the example of an area | region process to a block area. It is a figure which shows the example of determination of the auxiliary | assistant correction amount according to the variation degree of the distribution of gradation data value. It is a figure which shows the table which matched the standard deviation value with the auxiliary | assistant correction amount. It is a figure which shows the determination process of the last correction amount. It is a figure which shows the example of correction | amendment operation | movement of a burn-in phenomenon. It is a figure which shows the other example of a burn-in phenomenon correction apparatus. It is a figure which shows the other example of a burn-in phenomenon correction apparatus. It is a figure which shows the internal structural example of a moving image still image determination part. It is a figure which shows the example of a determination operation | movement of a moving image and a still image. It is a figure which shows the internal structural example of a brightness degradation correction | amendment part. It is a figure which shows the correction operation example of the final correction amount according to a moving image area | region and a still image area | region. It is a figure which shows the other example of a burn-in phenomenon correction apparatus. It is a figure which shows the internal structural example of a brightness determination part. It is a figure which shows the internal structural example of a brightness determination part. It is a figure which shows the internal structural example of a brightness degradation correction | amendment part. It is a figure which shows the example of correction | amendment operation | movement of the final correction amount according to a bright area and a dark area. It is a figure which shows the example of correction | amendment operation | movement of the final correction amount according to a bright area and a dark area. It is a figure which shows the system example which mounts the burn-in phenomenon correction apparatus in the self-light-emitting device. 1 is a diagram illustrating a system example in which a burn-in phenomenon correction apparatus is mounted on an image processing apparatus. It is a figure which shows the system example in the case of using a motion vector for determination of a moving image area | region and a still image area | region.

Explanation of symbols

1, 21, 31, 41, 55, 61, 73 Burn-in phenomenon correction device 3 Deterioration amount difference calculation unit 5 Cumulative deterioration amount difference accumulation unit 7 Standard correction amount determination unit 9 Display data area conversion unit 11 Tonal variation calculation unit 13 Auxiliary Correction amount determination unit 15 Final correction amount determination unit 17, 35, 45 Brightness deterioration correction unit 33 Movie still image determination unit 43 Brightness determination unit

Claims (9)

A method of correcting a burn-in phenomenon of a self-light-emitting device in which a plurality of self-light-emitting elements are arranged in a matrix,
Processing to divide gradation data into block areas to which corresponding pixels belong;
A process of calculating information indicating the degree of variation in the distribution of gradation data values associated with each block area;
A process of determining an auxiliary correction amount for each block area according to the degree of variation in the distribution of the gradation data values;
Based on the display signal after the burn-in correction, a process for obtaining a deterioration amount difference with respect to the comparison target pixel of all pixels,
A process of cumulatively adding the deterioration amount difference for each pixel and calculating a cumulative deterioration amount difference generated for each pixel;
A process of sequentially determining a standard correction amount used for burn-in correction based on the cumulative deterioration amount difference;
Correcting the standard correction amount with a corresponding auxiliary correction amount, and determining a final correction amount;
And a process of correcting a display signal before the burn-in correction based on the final correction amount. The burn-in phenomenon correction method according to claim 1,
The burn-in phenomenon correction method, wherein the information indicating the degree of variation in the gradation data distribution is a variance value or a standard deviation value. The burn-in phenomenon correction method according to claim 1,
The burn-in phenomenon correction method, wherein the maximum value of the standard correction amount is limited to a range in which deterioration in image quality due to burn-in correction is difficult to be visually recognized in a pattern in which deterioration in image quality is easily perceived. In the burn-in phenomenon correction method according to claim 1,
The auxiliary correction amount is determined to be a larger value as the degree of variation in the gradation data value distribution is larger, and is determined to be a smaller value as the degree of variation in the gradation data value distribution is smaller. Method. In the burn-in phenomenon correction method according to claim 1,
The burn-in phenomenon correction method, wherein the final correction amount is calculated as a value obtained by multiplying the standard correction amount by the auxiliary correction amount. In the burn-in phenomenon correction method according to claim 1,
The burn-in phenomenon correction method, wherein the final correction amount is calculated as a value obtained by adding the auxiliary correction amount to the standard correction amount, or a value obtained by subtracting the auxiliary correction amount from the standard correction amount. A self-light-emitting device in which a plurality of self-light-emitting elements are arranged in a matrix,
A display signal region forming unit that divides gradation data into block areas to which corresponding pixels belong;
A gradation variation calculator that calculates information indicating the degree of variation in the distribution of gradation data values associated with each block area;
An auxiliary correction amount determination unit that determines an auxiliary correction amount for each block area according to the degree of variation in the distribution of the gradation data values;
A deterioration amount difference calculation unit for obtaining a deterioration amount difference with respect to the comparison target pixel of all the pixels based on the display signal after the burn-in correction,
A cumulative deterioration amount difference accumulation unit that cumulatively adds the deterioration amount difference for each pixel and calculates a cumulative deterioration amount difference that has occurred for each pixel;
A standard correction amount determination unit that sequentially determines a standard correction amount used for burn-in correction based on the accumulated deterioration amount difference;
A final correction amount determination unit for correcting the standard correction amount with a corresponding auxiliary correction amount and determining a final correction amount;
A self-luminous device comprising: a deterioration correction unit that corrects a display signal before burn-in correction based on the final correction amount. A burn-in phenomenon correction device that corrects a burn-in phenomenon of a self-light-emitting device in which a plurality of self-light-emitting elements are arranged in a matrix,
A display signal region forming unit that divides gradation data into block areas to which corresponding pixels belong;
A gradation variation calculator that calculates information indicating the degree of variation in the distribution of gradation data values associated with each block area;
An auxiliary correction amount determination unit that determines an auxiliary correction amount for each block area according to the degree of variation in the distribution of the gradation data values;
A deterioration amount difference calculation unit for obtaining a deterioration amount difference with respect to the comparison target pixel of all the pixels based on the display signal after the burn-in correction,
A cumulative deterioration amount difference accumulation unit that cumulatively adds the deterioration amount difference for each pixel and calculates a cumulative deterioration amount difference that has occurred for each pixel;
A standard correction amount determination unit that sequentially determines a standard correction amount used for burn-in correction based on the accumulated deterioration amount difference;
A final correction amount determination unit for correcting the standard correction amount with a corresponding auxiliary correction amount and determining a final correction amount;
A burn-in phenomenon correction apparatus, comprising: a deterioration correction unit that corrects a display signal before burn-in correction based on the final correction amount. Processing to divide gradation data into block areas to which corresponding pixels belong;
Processing for calculating information indicating the degree of variation in the distribution of gradation data values associated with each block area;
A process of determining an auxiliary correction amount for each block area according to the degree of variation in the distribution of the gradation data values;
Based on the display signal after the burn-in correction, a process for obtaining a deterioration amount difference with respect to the comparison target pixel of all pixels,
A process of cumulatively adding the deterioration amount difference for each pixel and calculating a cumulative deterioration amount difference generated for each pixel;
A process of sequentially determining a standard correction amount used for burn-in correction based on the cumulative deterioration amount difference;
Correcting the standard correction amount with a corresponding auxiliary correction amount, and determining a final correction amount;
Correcting the burn-in phenomenon of the self-light-emitting device in which a plurality of self-light-emitting elements are arranged in a matrix by causing the computer to execute a process of correcting the display signal before the burn-in correction based on the final correction amount. A featured program.

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