KR20060096622A - The plasma display panel operating equipment and the methode of the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel driving apparatus and a driving method thereof, comprising: a comparison unit for comparing on / off of subfields having the same sustain number weight between adjacent cells, and the on / off number of each subfield according to the comparison result. If the difference is greater than or equal to the reference value, and includes a mapping unit for performing different subfield mapping, and compare the on / of of the subfield having the same number of sustain weights of adjacent cells to compare the area where the pseudo contour can occur The detection of pseudo contours can be reduced by performing subfield mapping between the regions where the pseudo region is likely to occur and the regions other than the regions where the pseudo region is likely to occur.

Plasma Display Panel, PDP, Pseudocontour, Contour Noise, Subfield Mapping

Description

 Plasma display panel driving device and driving method thereof {The plasma display panel operating equipment and the methode of the same}

1 is a block diagram schematically showing a driving apparatus of a plasma display panel according to the prior art;

FIG. 2A illustrates an example in which a white stripe pseudo contour appears on a plasma display panel according to the prior art; FIG.

2B is a view showing an example in which a black band pseudo contour appears on a plasma display panel according to the prior art;

3 is a view illustrating a plasma display panel in which a moving image and a still image according to the related art are simultaneously displayed;

4 is a configuration diagram showing a configuration of a plasma display panel driving apparatus according to the present invention;

FIG. 5 is a diagram illustrating a method for finding a region in which a pseudo contour may occur in a specific frame in the plasma display panel according to the present invention.

6 is a flowchart illustrating a method of driving a plasma display panel according to the present invention.

<Explanation of symbols on main parts of the drawings>

110: comparison unit 120: mapping unit

130: memory

The present invention relates to an apparatus for driving a plasma display panel and a driving method thereof. In particular, a region in which pseudo contours are likely to be detected is compared by comparing whether a subfield having the same sustain number weight of adjacent cells is on or off. The present invention relates to a plasma display panel driving apparatus and a driving method thereof capable of preventing pseudo contouring by performing subfield mapping between regions in which pseudo contours are likely to occur and subregions according to a detection result.

The plasma display panel drives the corresponding pixel according to gray level data of the image. The plasma display panel is driven by dividing one frame into several subfields having different number of emission times in order to express gray scales. The subfield is divided into a reset period for uniformly generating a discharge, an address period for selecting a cell to be discharged, and a sustain period for implementing gray levels according to the number of discharges.

For example, assuming that the plasma display panel uses eight subfields to represent 256 levels of gray scale, the reset period and the address period of each subfield are the same, but the sustain period is 2 ⁿ (for each subfield). n = 0, 1, 2, 3, 4, 5, 6, 7) and the sustain period (pulse width) is increased because the intensity (applied voltage) of each sustain signal is the same and the amount of light emitted per hour is the same. If it increases, the integral amount increases so that the screen looks bright and gray scale expression by subfield is possible.

To this end, as shown in FIG. 1, the apparatus for driving a plasma display panel according to the related art includes an inverse gamma correction unit 10, an error diffusion unit 20, and a subfield mapping for gray scale expression, into which an image signal is input. It comprises a unit 30 and a data alignment unit 40.

The inverse gamma correction unit 10 inversely gamma corrects an input image signal and linearly converts luminance values according to grayscale values of the image signals to match the characteristics of the plasma display panel. The error diffusion unit 20 finely adjusts luminance values between adjacent cells in a unit pixel area for more accurate gray level expression, and the subfield mapping unit 30 separates data output from the error diffusion unit according to the luminance relative ratio. Subfield mapping is performed, and the data alignment unit 40 arranges the image data application order according to the characteristics of the plasma display panel.

Since the plasma display panel expresses the gray scale by subfield combination, contour noise occurs in the moving image, and the screen display quality is deteriorated when the moving image is reproduced by the pseudo contour noise.

If 128 levels of gray are represented in the previous frame and 127 levels of gray are expressed in the next frame, the discharge occurs in the plasma display panel as shown in FIG. 2A.

In this case, the brightness within the unit time is instantaneously increased to express 255 levels of gray scale. That is, the brightness displayed on the plasma display panel is displayed at the moment when 127 levels of 127 levels are expressed after 128 levels of gradations are expressed, and then 127 levels of gradations are expressed for a short period of time so that it looks like a white band. .

On the contrary, if 127 levels of grayscale are expressed in the previous frame and 128 levels of grayscale are expressed in the next frame, the discharge proceeds in the plasma display panel as shown in FIG. 2B, where the brightness within the unit time decreases momentarily. 0 level gradation is expressed.

In the plasma display panel, when 127 levels of gradation are expressed and the level of 128 levels of gradation is started, the period where no discharge is made is long, and then 0 levels of gray are instantaneously expressed and then 128 levels of gradation are expressed, so that it looks like a black band. .

Such pseudo contours are mainly shown in the video. In order to reduce the occurrence of pseudo contours, a method of detecting sub-field mapping between moving parts and stationary parts by detecting moving parts and still parts is used.

However, when performing subfield mapping between moving images and still images differently, detection of still images and moving images is important. Generally, the comparison between the previous frame and the next frame compares the still image and the moving image according to the gray level difference of each cell. Perform detection.

In this case, as shown in FIG. 3, in the case of a screen in which a circle having the same brightness is moved, the cells representing the circle in both the previous frame (solid line) and the next frame (dashed line) because the gray levels of the cells inside the circle are the same. Since the shaded portion is detected as a still image because there is no change in gradation, it is impossible to detect all moving portions in one frame.

Therefore, since the inside of the circle, which is a moving image, is actually detected as a still image and subfield mapping is performed, a pseudo contour is generated inside the circle determined as the still image.

As described above, when detecting the still image and the video according to the gradation difference of each cell by comparing the previous frame and the next frame, there is a problem in that all moving parts cannot be detected.

The present invention has been made to solve the above-mentioned problems of the prior art, and compares whether a subfield having the same sustain number weight of adjacent cells is on or off to detect an area where pseudo contours may occur in a specific frame. Another object of the present invention is to provide a plasma display panel driving apparatus and a driving method thereof capable of eliminating pseudo contours by performing subfield mapping between regions where pseudo contours are unlikely to occur.

The plasma display panel driving apparatus according to the present invention for solving the above problems is a comparison unit for comparing the on / off of the subfield having the same number of sustain weights between adjacent cells, and on / off of each subfield according to the comparison result If the number difference is greater than or equal to the reference value is characterized in that it comprises a mapping unit for performing different subfield mapping.

In addition, in the method of driving the plasma display panel according to the present invention, the on / off number difference between subfields having the same sustain number weight of adjacent cells is compared by comparing the on / off of the subfields having the same sustain number weight of adjacent cells. In the above case and below the reference value, the subfield mapping is performed differently.

Hereinafter, a plasma display panel driving apparatus of the present invention will be described with reference to the accompanying drawings.

FIG. 4 is a block diagram showing a configuration of a plasma display panel driving apparatus according to the present invention, and FIG. 5 is a view showing a method for finding a region in which a pseudo contour may occur in a specific frame in the plasma display panel according to the present invention. It is also.

As shown in FIG. 4, the apparatus for driving a plasma display panel of the present invention basically includes a comparator 110 comparing on / off of subfields having the same sustain number weight between adjacent cells, and each sub according to the comparison result. If the difference between the on / off number of the field is greater than or equal to the reference value is configured to include a mapping unit 120 for performing different sub-field mapping.

The comparison unit 110 compares on / off of subfields having the same sustain number weight between adjacent cells with respect to all subfields or specific subfields constituting one frame.

The comparison unit 110 may perform a XOR operation on / off between subfields having the same number of sustain weights, and may be different for each sustain number of the subfields having the same number of sustain weights. The second calculator 112 adds weights and adds the weights.

For example, assuming that the plasma display panel expresses gray scale using eight subfields, and that the subfield data of two adjacent cells is 11110000 and 00001111, respectively, the first calculating unit 111 is configured to display the two adjacent cells. 11111111 is output by performing an XOR operation on or off of a subfield having the same number of sustain weights.

In this case, when the subfield is 1, the subfield is turned on during the corresponding subfield period, so that discharge occurs in the cell. If the subfield is 0, the subfield is turned off during the subfield period, and no discharge occurs in the cell.

That is, in the case of the first cell, since the subfield data is 11110000, the first cell discharges during the first four subfield periods SF0 to SF3, and no discharge occurs during the next four subfield periods SF4 to SF7. In the case of the second cell, since the subfield data is 00001111, discharge does not occur during the first four subfield periods SF0 to SF3, and discharge occurs during the next four subfield periods SF4 to SF7.

Each subfield has a different number of sustains, and the number of sustains increases from the first subfield SF0 to the last subfield SF7, and the brightness increases as the number of sustains increases. 111), when performing the XOR operation, it is preferable to perform XOR operations between subfields having the same sustain number weight. When XOR operation is performed, SF0 performs SFOR between SF0s and SF1 performs SFOR between SF1s.

The second calculating unit 112 gives different weights for each digit of the data output from the first calculating unit 111 and adds them together. You can get results. For example, if the weight is added from 2 ⁰ to 2 ⁷ and the sums are added, in the above example, the operation result of the second operation unit is 255.

The mapping unit 120 may be more expressible than the case where the on / off number difference is less than the reference value when the on / off number difference between subfields having the same sustain number weight of adjacent cells is greater than or equal to the reference value. Subfield mapping is performed so that the number of gray levels is small.

That is, since the operation result of the comparison unit 110 indicates the difference in the number of on / off between subfields having the same sustain number weight in the adjacent cell, the operation result of the second operation unit 112 is greater than or equal to a predetermined reference value. The two adjacent cells become areas where pseudo contours are likely to occur.

Accordingly, the mapping unit 120 performs subfield mapping so that the number of gray levels that can be expressed is smaller than the case where the calculation result of the second calculating unit 112 is greater than or equal to the reference value to reduce the pseudo contour noise that generates pseudo contours. .

For example, when the reference value for determining an area where pseudo contours may occur and a non-area is determined as 150, in the above example, since the calculation result of the second calculation unit 112 is 255, the two cells are pseudo contours. The subfield mapping is performed such that the number of expression gray levels is smaller than that in which the pseudo contour is not generated, so that the pseudo contour is not generated and the pseudo contour is not generated, and both cells have the same subfield mapping.

In this case, the weight applied by the second calculating unit 112 and the reference value for measuring a region other than the region where the pseudo contour may occur are not limited to the present specification, and may be set differently according to the characteristics of the plasma display panel and the circuit load. Do.

In addition, the mapping unit 120 sets an on-off number difference between subfields having the same sustain number weight of adjacent cells to be greater than or equal to a reference value so that the number of gray levels that can be represented by the pseudo contour may be set to 256 levels or less. Perform subfield mapping if possible.

The plasma display panel driving apparatus may be configured to compare two adjacent cells in one frame and perform subfield mapping by detecting a region where a pseudo contour may occur and a region other than the above, and for this purpose, the plasma display panel driving apparatus of the present invention By configuring a block of 2 * 1 or more in a specific frame, it may be configured to perform subfield mapping by determining whether or not pseudo contours are possible in all blocks of cells.

To this end, the plasma display panel driving apparatus of the present invention further includes a memory unit 130 in which subfield data of each cell in the block is stored, and the block size is used to determine the size of the memory unit and the possibility of generating pseudo contours. It may be set differently according to the criteria to determine.

As shown in FIG. 5, when the block size is 4 * 2, the subfield data of each cell in the block is stored in the memory unit 130.

As described above, when the plasma display panel driving apparatus of the present invention detects an area in which a pseudo contour may occur in block units, the first operation unit 111 sequentially moves from the first row to the last row of one frame. XOR operation is performed between the left and right of the subfields having the same sustain number weight with respect to the left and right adjacent cells.

That is, when the block size is 4 * 2, the first calculating unit 111 performs a total of six XOR operations from the upper left to the lower right from the first to the eighth cells, and the memory unit 130 also performs the calculation result. Can be configured to be stored in

For example, when the subfield data of cells 1 to 8 are 11110000, 11101111, 11100000, 00001111, 11001000, 11000111, 00111100, 11010000, respectively, the first operation unit 111 may be 11110000 and 11101111, 11101111 and 11100000, Calculate 00011111, 00001111, 11101111, 11000111, 00001111, 11111011, 11101100 by performing XOR operation on 11100000 and 00001111, 11001000 and 11000111, 11000111 and 00111100, 00111100 and 11010000 respectively to turn on / off the subfield with the same sustain number weight Calculate the value.

The second calculating unit 112 is configured to assign different weights to each of the sustain number weights of the subfields and add them to the calculation result of the first calculating unit 111 of all the block cells. That is, different weights are added for each digit to the calculation result value of the first calculation unit 111 and sum them.

For example, if the weight is added from 2 ⁰ to 2 ⁷ and summed, the calculation result values of the first calculator 111 have 248, 240, 247, 240, 223, and 55, respectively, and the second calculator 112 is used. The computed value of becomes 1253, which is the sum of the above values.

The mapping unit 120 determines that the on / off number difference of the subfields having the same sustain number weight between adjacent cells is greater than or equal to the reference value in all of the block cells as a result of the operation of the second calculating unit 112. The subfield mapping is performed in the same manner, and the subfield mapping is performed such that the number of gray levels that can be expressed is smaller than that when the on / off number difference of the subfields is equal to or less than a reference value.

If the operation result of the second operation unit 112 is equal to or greater than a predetermined reference value, the difference between the on / off number of subfields having the same sustain number weight between adjacent cells in the block becomes equal to or greater than the reference value, and the block may generate pseudo contours. It becomes a possibility area.

Therefore, when a specific block is detected as a region where a pseudo contour may occur, the mapping unit 130 performs subfield mapping so that all the cells of the block have the same subfield mapping.

In this case, it is preferable that the subfield mapping formed for the area where pseudo contour may occur is set to be less than 256 levels, and this should be set so that the number of gray levels that can be expressed is smaller than the area where pseudo contour cannot be generated. .

If the block size is 4 * 2, it is assumed that if the calculation result of the second calculation unit 112 is 900 or more, it is assumed that the detection is an area in which pseudo contour is likely to occur. Since the value is 1480, the entire block is detected as an area where pseudo contours may occur, and subfield mapping is performed.

As described above, the plasma display panel driving apparatus of the present invention performs subfield mapping on one block and then performs subfield mapping on the next block, wherein the new block may include a portion of a previously set block. It may be set without including the previously set block.

Accordingly, the plasma display panel driving apparatus of the present invention detects areas where pseudo contours are likely to occur and blocks other than pseudo contours from the upper left to the lower right in one frame. By performing the same subfield mapping of the entire block to be smaller than the area where the pseudo contour is unlikely, the pseudo contour noise generated in the area where the pseudo contour may be generated can be reduced to eliminate the pseudo contour.

In addition, the plasma display panel driving apparatus of the present invention compares a subfield having the same sustain number weight with respect to an adjacent cell, and detects a region (not shown) that detects a region where a pseudo contour may occur in a specific frame and not the region; It is configured to include a mapping unit (not shown) that performs the sub-field mapping of the region and the region other than the possibility of generating a pseudo contour result.

The detection unit compares subfields having the same sustain number weight with respect to neighboring cells in one frame, and detects an area in which a pseudo contour may occur in the frame, and the mapping unit generates pseudo contours according to the detection result of the detection unit. Perform subfield mapping differently for potential and non-probable areas.

As the mapping unit performs subfield mapping so that the expression gray level becomes small for an area that is not likely to generate pseudo contours, the pseudo contour noise can be reduced to eliminate pseudo contour generation.

6 is a flowchart illustrating a method of driving a plasma display panel according to the present invention. Referring to FIG. 6, a driving method of a plasma display panel of the present invention will be described.

The driving method of the plasma display panel of the present invention compares the on / off of subfields having the same sustain number weight with respect to neighboring cells, and the on / off number difference between subfields having the same sustain number weight of neighbor cells is greater than or equal to the reference value. The subfield mapping is performed differently from the case below the reference value.

To this end, first, an XOR operation (S2) is performed between subfields having the same sustain number weight of adjacent cells in the first step.

In this case, the first step is to perform an XOR operation on / off between all subfields constituting one frame or between subfields having the same sustain number weight of adjacent cells for all subfields or specific subfields. Performs an XOR operation on all subfields.

In the second step, different weights are added for each sustain number weight of the subfield to the result of the XOR operation for each subfield of the first step (S3).

In the third step, when the calculation result of the second step is greater than or equal to the reference value (S4), the subfield mapping is performed in which the number of expression gray scales is smaller than that of the less than or equal to the reference value (S7).

The reference value is a reference value for dividing an area with a possibility of generating a pseudo contour and an area without a possibility. When the calculation result of the second step is greater than or equal to the reference value, the two adjacent cells become areas with a possibility of generating a pseudo contour.

The plasma display panel driving method may further include a block generation step of forming blocks of 2 * 1 or more before the first step (S1).

When subfield mapping is performed by forming blocks of 2 * 1 or more, the method of driving the plasma display panel according to the present invention performs subfield mapping differently by dividing a region other than a region that may generate pseudo contours in blocks.

That is, after the block is formed (S1), the XOR operation is performed on all the cells of the block (S2), and the same sustain number weight in the left and right adjacent cells from the upper left to the lower right in the block sequentially from the first row of the block. XOR operation is performed on / off between subfields having.

After the XOR operation on all the cells of the block, weighting is added to the calculation result (S3) to determine whether or not a pseudo contour is a possible area (S5).

That is, different weights are added for each sustain number weight to the XOR calculation result for each subfield having the same sustain number weight for all the cells of the block, and the sum is added (S3), and the result value is equal to or greater than a predetermined reference value (S4). Is determined as an area capable of generating a pseudo contour (S5), and if the result value is equal to or less than a reference value (S4), it is determined as an area where a pseudo contour does not occur (S6) and subfield mapping is performed (S7 to S8).

In this case, if it is determined that the pseudo contour can be generated, the subfield mapping of the entire block is performed in the same manner, and in this case, the subfield mapping performs the subfield mapping in which the number of expression gradations is smaller than that in which the pseudo contour cannot be generated.

In this way, blocks are composed for the entire frame, and whether or not pseudo contours are generated for each block is determined, and subfield mapping between areas where pseudo contours are likely to occur is performed differently, thereby reducing pseudo contour noise in a video. Eliminate pseudo contouring

As described above, the plasma display panel driving apparatus and the driving method thereof according to the present invention have been described with reference to the illustrated drawings. However, the present invention is not limited by the embodiments and drawings disclosed herein, and the technical spirit of the present invention is protected. It can be applied by those skilled in the art within the range to be.

The apparatus for driving a plasma display panel and the driving method thereof according to the present invention configured as described above are areas in which pseudo contours may occur in a specific frame by comparing on / off of subfields having the same sustain number weight of adjacent cells. The subfield mapping is performed so that the number of gray scales that can be expressed is smaller than the area where pseudo contours are unlikely to occur. By performing it differently, it is possible to remove pseudo contour noise.

Claims (15)

A comparison unit for comparing on / off of subfields having the same sustain number weight between adjacent cells, and different subfield mappings when the on / off number difference of each subfield is greater than or equal to a reference value according to the comparison result; Plasma display panel driving apparatus comprising a mapping unit. The method of claim 1, And the comparator is configured to compare on / off of subfields having the same sustain number weight between adjacent cells with respect to some or all subfields constituting one frame. The method of claim 1, The comparison unit performs a XOR operation on / off between subfields having the same number of sustain weights, and assigns different weights to each of the number of sustain weights to the calculation result value for each subfield having the same number of sustain weights. And a second calculating unit to add the plasma display panel. The method of claim 1, When the mapping unit compares the subfields having the same sustain number weight of adjacent cells as the comparison result of the comparison unit, when the on / off number difference is greater than or equal to the reference value, the mapping unit performs subfield mapping so that the number of gray levels that can be expressed is smaller than that when the on / off number difference is less than or equal to the reference value. And a plasma display panel drive device. The method of claim 4, wherein The subfield mapping when the on / off number difference is greater than or equal to the reference value, the number of gray levels that can be expressed is set to 256 levels or less. The method of claim 1, The plasma display panel driver further comprises a memory unit in which subfields of each cell are stored. The method of claim 6, And the adjacent cell is a block of 2 * 1 or more. The method according to claim 3 or 7, The first operation unit is configured to perform XOR operation on / off of a subfield having the same sustain number weight of left and right adjacent cells in a direction from the upper left cell to the lower right in the block sequentially from the first row of one frame. Plasma display panel drive device. The method of claim 1, The mapping unit performs the same operation on the subfield mapping of all the cells in the entire block when the difference between the on / off counts of the subfields having the same sustain number weight among the adjacent cells in the block all cells is equal to or greater than a reference value. Plasma display panel drive device characterized in that. A detection unit which compares subfields having the same sustain number weight of adjacent cells and detects regions other than the possibility of generating pseudo contours in a specific frame; Plasma display panel driving apparatus comprising a mapping unit for performing field mapping differently. Subfield mapping when the on / off count difference between subfields having the same sustain count weight of adjacent cells in a particular frame is greater than or equal to the reference value Plasma display panel driving method to perform differently. The method of claim 11, Performing a XOR operation on / off between subfields having the same sustain number weight of adjacent cells; A second step of adding different weights to the result of the XOR operation for each subfield for each sustain number weight of the subfield and adding them to each other; And a third step of performing subfield mapping with a smaller expression gray level than when the calculation result is greater than or equal to the reference value. The method of claim 12, And the adjacent cell is a block of 2 * 1 or more. The method of claim 12, In the first step, a plasma display panel is driven by performing XOR operation between subfields having the same sustain number weight of left and right adjacent cells from left to right in the block sequentially from the first row of the block. Way. The method of claim 15, And the third step performs subfield mapping of all the cells of the entire block in the same manner when the calculation result of the entire block of the second step is equal to or greater than a reference value.

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