KR100705841B1 - Plasma Display Apparatus and Image Processing Method thereof - Google Patents

Abstract

The present invention relates to a plasma display device, and more particularly, to a plasma display device capable of improving gray scale display capability by improving a plasma display device and an image processing method thereof.

In accordance with another aspect of the present invention, a plasma display device includes an inverse gamma correction unit configured to inverse gamma correct an image signal input from an external device; The rounding caused by error diffusion of the lower bits among the decimal bits of the inverse gamma corrected image signal is reflected in the upper bits of the decimal bits, and the upper bits of the fractional bits are error spread in a different error diffusion method than the lower bits. An error diffusion unit for reflecting the shifting generated by the integer bit of the video signal; And a subfield mapping unit for mapping the error spread image signal to a subfield mapping table.

Description

Plasma Display Apparatus and Image Processing Method {Plasma Display Apparatus and Image Processing Method}

1 is a view showing a method for implementing an image of a conventional plasma display device.

2 is a graph comparing luminance characteristics of a plasma display device and a cathode ray tube.

3 is a graph illustrating inverse gamma correction in a conventional plasma display apparatus.

4 is a view for explaining a method of mixing the conventional error diffusion and dithering.

5 is a diagram illustrating a problem caused by a conventional method of using error diffusion and dithering.

6 is a view for explaining a plasma display device according to an embodiment of the present invention.

7 is a view for explaining an error diffusion unit according to an embodiment of the present invention.

8 is a view for explaining an operating characteristic of the first error diffusion unit according to an embodiment of the present invention.

9 is a view for explaining the operating characteristics of the second error diffusion unit according to an embodiment of the present invention.

FIG. 10 is a diagram illustrating an error diffusion weighted lookup table according to the second error diffusion method of FIG. 9.

11 illustrates a plurality of error diffusion weighted lookup tables according to an embodiment of the present invention.

12 is a view for explaining an error diffusion direction according to an embodiment of the present invention.

13 is a view for explaining an error diffusion method according to another embodiment of the present invention.

***** Explanation of symbols for main parts of drawing *****

610, 710; Inverse gamma correction unit 620; Gain control

630, 720; Error diffusion units 640 and 730; Subfield Mapping Section

650; Data alignment unit 660; Data driver

721; Fractional bit separator 722; First error diffusion unit

723; Delay unit 724; First adding part

725; A second error diffusion unit 726; Error Diffusion Weighted Lookup Table Storage

727; Second adding part

The present invention relates to a plasma display device, and more particularly, to a plasma display device capable of improving gray scale display capability by improving a plasma display device and an image processing method thereof.

 In general, a plasma display device includes a plasma display panel in which a partition wall formed between a front substrate and a rear substrate forms one unit cell. Each cell is filled with a main discharge gas such as neon (Ne), helium (He) or a mixture of neon and helium (Ne + He) and an inert gas containing a small amount of xenon. When discharged by a high frequency voltage, the inert gas generates vacuum ultraviolet rays and emits phosphors formed between the partition walls to realize an image. Such a plasma display device has been spotlighted as a next generation display device because of its thin and light configuration.

1 is a view showing a method for implementing an image of a conventional plasma display device.

As shown in FIG. 1, the plasma display apparatus divides one frame period into a plurality of subfields having different discharge times, and emits a plasma display panel in a subfield period corresponding to a gray value of an input image signal. An image is implemented.

Each subfield is divided into a reset period for uniformly generating a discharge, an address period for selecting a discharge cell, and a sustain period for implementing gray levels according to the number of discharges. For example, when the image is to be displayed with 256 gray levels, the frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields.

In addition, each of the eight subfields is divided into a reset period, an address period, and a sustain period. Here, the sustain period is increased at the ratio of 2 ⁿ (n = 0,1,2,3,4,5,6,7) in each subfield. As described above, since the sustain period is changed in each subfield, gray levels of an image can be realized.

2 is a graph comparing luminance characteristics of a plasma display device and a cathode ray tube.

As shown in FIG. 2, a cathode-ray tube and a liquid crystal display display a desired gray scale by controlling the displayed light in an analog manner with respect to an input video signal. It has a luminance characteristic of. In contrast, since the plasma display device expresses gray scales by modulating the number of light pulses using a matrix array of discharge cells that can be turned on / off, the plasma display apparatus has a linear luminance characteristic. The gray scale expression method of the plasma display device is called a PWM (Pulse Width Modulation) method.

In this case, the display device such as the cathode ray tube is a power multiplier of the display current is proportional to 2.2 multipliers, so that the input external video signal such as a broadcast signal transmits a signal corresponding to the inverse of the 2.2 multiplier. Therefore, a plasma display device having a linear brightness characteristic needs to inversely gamma correct an image signal input from the outside.

3 is a graph illustrating inverse gamma correction in a conventional plasma display apparatus.

In Fig. 3, the target luminance is an ideal inverse gamma result to be corrected, the actual luminance is a measured luminance value as a result after inverse gamma correction, and the PDP luminance is a luminance value of 3 or less measured in the absence of inverse gamma correction. It is shown.

 As shown in FIG. 3, the target luminance is expressed as luminance values having different gray level values of 61 steps from 0 to 60, respectively. In contrast, the actual luminance is expressed by only eight luminance values of 61 gray levels from 0 to 60. Therefore, when the inverse gamma correction is performed in the plasma display apparatus, there is a problem in that it is impossible to express enough gray scales in a dark area, thereby generating a contour noise in which images are aggregated.

 In order to improve the insufficient gray scale expression power of the plasma display apparatus, a half tone method such as a dithering method and an error diffusion method is used.

First, the error diffusion method is a method for spatially correcting an error that is discarded by causing a minority value, that is, an error to affect neighboring pixels, generated when the gray value of the pixel is quantized. In this error diffusion method, the error diffusion weights for neighboring pixels are constantly set, and are repeated line by line and frame by frame. Accordingly, there is a problem in that the same error diffusion pattern is generated for the entire screen due to a constant error diffusion weight.

Next, the dithering method is a method of determining whether or not a carry occurs by comparing the grayscale value of each pixel with a specific threshold value of the dither mask. That is, it is a method of increasing the lack of gradation expression power by turning on the off-pixel and turning off the off-pixel. This dithering method uses a plurality of dither masks having a constant pattern. Accordingly, there is a problem in that a dither mask pattern is displayed on the screen because a constant dither mask is repeatedly used.

In order to overcome the problems of the error diffusion method and the dithering method, conventionally, the error diffusion method and the dithering method are used in combination, as shown in FIG. 4, to improve the gray scale expression power.

4 is a view for explaining a method of mixing the conventional error diffusion and dithering.

As shown in FIG. 4, in the method of using error spreading and dithering, first, gray level data of an inverse gamma corrected video signal is divided into integer bits and decimal bits, and the fractional bits are further divided into upper bits and lower bits. Subsequently, the lower bit performs error spreading and reflects this to the upper bit when the rounding occurs. In addition, the higher bit performs dithering and reflects this to the integer bit when the rounding occurs. At this time, the integer bit is referred to as real gradation, and finally, by implementing an image of the plasma display apparatus using the real gradation value, various gradation representations are possible. On the other hand, the method of using error diffusion and dithering also has a problem of generating flicker as shown in FIG.

5 is a diagram illustrating a problem caused by a conventional method of using error diffusion and dithering.

As shown in FIG. 5, in the related art, error diffusion is performed on all pixels every frame by using adjacent pixels at a predetermined position and a constant error diffusion coefficient, so that dithering may be performed with a different dither mask pattern every frame. When the patterns are not matched, various problems occur.

For example, as shown in FIG. 5, the error diffusion pattern and the dither mask pattern of type A are matched with each other to generate pixels, and the desired image is realized while the error diffusion pattern and the dither mask pattern of type B are unbalanced. The pixels do not match with each other, and the image is not realized at all. As such, when the error diffusion pattern and the dither mask pattern do not match, the luminance difference of the displayed screen is generated at a maximum of 50%. This luminance difference causes flickering of the screen. Here, the pattern of error diffusion and dithering of FIG. 5 indicates a pixel position of a pixel where a spot is generated, and a pattern of a displayed screen indicates a position of a pixel that is actually turned on / off depending on whether a spot is raised.

In addition, due to the above problem, the gray level of each of R (Red), G (Green), and B (Blue) of the original video signal is distorted, thereby changing the color of the image.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a plasma display apparatus and an image processing method capable of suppressing noise and flicker displayed on a screen during driving by improving the plasma display apparatus and an image processing method thereof. There is a purpose.

In addition, another object of the present invention is to provide a plasma display device and an image processing method thereof capable of improving gray scale expression.

Further, another object of the present invention is to provide a plasma display device and an image processing method thereof capable of preventing distortion of an image to be implemented.

In order to achieve the above object, the plasma display device of the present invention includes an inverse gamma correction unit for inverse gamma correction of an image signal input from the outside; The rounding caused by error diffusion of the lower bits among the decimal bits of the inverse gamma corrected image signal is reflected in the upper bits of the decimal bits, and the upper bits of the fractional bits are error spread in a different error diffusion method than the lower bits. An error diffusion unit for reflecting the shifting generated by the integer bit of the video signal; And a subfield mapping unit for mapping the error spread image signal to a subfield mapping table.

The error spreader of the present invention uses a first error spreader that randomly spreads any one of the upper bits or the lower bits using a random coefficient value and the remaining bits of the upper or lower bits of the image signal. And a second error diffusion unit for error diffusion using an error diffusion weight assigned according to the gray value.

The first error diffusion part of the present invention adds the random coefficient value to the error diffusion coefficient value to diffuse the error diffusion coefficient value generated from at least one neighboring pixel of a predetermined pixel to the predetermined pixel. Characterized in that.

The second error spreader may include at least one error spread weight lookup table storage in which an error spread weight allocated according to the gray value is stored in advance.

At least one of the first error diffusion unit and the second error diffusion unit of the present invention is characterized in that the error coefficient value between neighboring pixels is diffused in a random direction.

The upper bit of the present invention is characterized by being 1 bit or more and 3 bits or less from the most significant part of the decimal bit.

The lower bit of the present invention is characterized by being 1 bit or more and 4 bits or less from the bit consecutive to the higher bit.

The error diffusion unit divides the upper bit and the lower bit into at least one bit unit and error spreads the divided bits.

The image processing method of the plasma display apparatus of the present invention includes an inverse gamma correction step of performing inverse gamma correction on an image signal input from the outside; The rounding caused by error diffusion of the lower bits among the decimal bits of the inverse gamma corrected image signal is reflected in the upper bits of the decimal bits, and the upper bits of the fractional bits are error spread in a different error diffusion method than the lower bits. An error diffusion step of reflecting the generated rounding to an integer bit of the video signal; And a subfield mapping step of mapping the error spread video signal to a subfield mapping table.

In the error spreading step of the present invention, a first error spreading method of random error spreading one of the upper bits or the lower bits using a random coefficient value and the remaining bits of the upper bits or the lower bits are image signals. And a second error diffusion method of error diffusion using an error diffusion weight assigned according to the gray level value.

The first error diffusion method of the present invention adds the random coefficient value to the error diffusion coefficient value when the error diffusion coefficient value generated from at least one neighboring pixel of a predetermined pixel is diffused to the predetermined pixel. It is characterized by spreading.

The second error spreading method may include storing at least one error spreading weight lookup table in which an error spreading weight allocated according to the grayscale value is stored in advance.

At least one of the first error diffusion method and the second error diffusion method of the present invention is characterized in that the error coefficient values between neighboring pixels are diffused in a random direction.

The upper bit of the present invention is characterized by being 1 bit or more and 3 bits or less from the most significant part of the decimal bit.

The lower bit of the present invention is characterized by being 1 bit or more and 4 bits or less from the bit consecutive to the higher bit.

The error diffusion step of the present invention is characterized by dividing the upper bit and the lower bit by at least one or more bit units, and each of the divided bits by error diffusion.

Hereinafter, with reference to the accompanying drawings, a specific embodiment according to the present invention will be described.

6 is a view for explaining a plasma display device according to an embodiment of the present invention.

As shown in FIG. 6, the plasma display apparatus according to the exemplary embodiment of the present invention includes an inverse gamma correction unit 610, a gain control unit 620, an error diffusion unit 630, a subfield mapping unit 640, and data alignment. The unit 650 and the data driver 660 are provided.

The inverse gamma correction unit 610 inversely gamma corrects an input image signal and linearly converts a displayed luminance value according to a gray value of the input image signal.

The gain control unit 620 transmits the R (Red), G (Green), and B (Blue) image signals inversely gamma corrected by the inverse gamma correction unit 610 to a user or a set maker. The gain is adjusted for each of the red, green, and blue colors by multiplying the gain value that can be adjusted by. The gain controller 620 may set a color temperature desired by the user or the set maker. In addition, the gain controller may or may not be included in the plasma display apparatus as needed according to an embodiment of the present invention.

The error diffusion unit 630 may perform error diffusion processing on the image signal input from the gain control unit 620 to finely adjust the luminance value displayed according to the gray value, thereby improving the gray scale expression power. That is, the fractional bits, i.e., error components, of the video signal generated by inverse gamma correction are spread to neighboring pixels.

The error diffusion unit 630 according to an embodiment of the present invention reflects a carry caused by error diffusion of the lower bits of the decimal bits of the inverse gamma corrected image signal to the upper bits of the decimal bits, The rounding caused by error diffusion of the upper bits among the bits in an error diffusion scheme different from the lower bits is reflected in the integer bits of the video signal. As described above, error diffusion is performed by dividing the lower bit and the upper bit, and error diffusion is performed in a different error diffusion scheme, thereby solving the problems caused by the conventional constant error diffusion pattern and dither mask pattern. A more detailed description of the error diffusion unit 630 according to an embodiment of the present invention will be described later with reference to FIGS. 7 to 13.

The subfield mapping unit 640 maps an image signal input from the error diffusion tone unit 630 to a preset subfield mapping table.

The data sorter 650 sorts the spatially sorted subfield mapping data input from the subfield mapper 640 into temporal data.

The data driver 660 receives the data aligned in time by the data aligning unit 650 and supplies an address driving pulse to an address electrode (not shown) of the plasma display panel, thereby realizing an image of the plasma display apparatus.

7 is a view for explaining an error diffusion unit according to an embodiment of the present invention.

As shown in FIG. 7, the error spreader 720 according to an embodiment of the present invention may include a decimal bit separator 721, a first error spreader 722, a delay unit 723, and a first adder. 724, a second error spreader 725, an error diffusion weighted lookup table storage 726, and a second adder 727.

The fractional bit separator 721 receives the fractional bits of the image signal from the inverse gamma correction unit 710 and divides the upper and lower bits. In order to effectively perform the error spreading, it is desirable to adjust the upper bits from 1 to 3 bits or less from the top of the decimal bit to the lower, and the lower bits from 1 to 4 bits or less from the bit consecutive to the upper bits. Do.

The first error spreader 722 randomly spreads the lower bits among the decimal bits using a random coefficient value. The rounding of the lower bits error-spread through the first error spreader 722 is then reflected as the upper bits.

The delay unit 723 delays input of the upper bits into the second error spreader 725 while the lower bits of the decimal bits are error-spread in the first error spreader 722. That is, the delay unit 723 is for error spreading the upper bits after reflecting the lower bits to the upper bits through the error diffusion.

The first summation unit 724 reflects information on whether the rounding from the lower bit to the higher bit input from the first error spreading unit 722 is reflected in the upper bit input from the delay unit 723.

The second error spreader 725 uses the error spread weights assigned to the upper bits reflecting the rounding of the lower bits input from the first adder 724 according to the gray level of the image signal to spread the errors. The second error spreader 725 includes at least one error spread weight lookup table storage unit 726 in which error spread weights allocated according to grayscale values are stored in advance.

The second adder 727 reflects the information on whether the rounding from the upper bits input from the second error spreader 725 to the integer bits occurs in the integer bits input from the inverse gamma correction unit 710. The reflected integer bit image signal is input to the sub-field mapping unit 730.

Here, in FIG. 7, the block configuration in which the first error spreader 722 error-spreads the lower bits and the second error spreader 725 error-spreads the upper bits reflected by the rounding is exemplified. In another embodiment, the first error spreader and the second error spreader are switched to each other so that the second error spreader error-diffuses the lower bits first, and the first error spreader error-diffusions the higher bits reflected thereafter. Block configurations are also possible.

8 is a view for explaining an operating characteristic of the first error diffusion unit according to an embodiment of the present invention.

As shown in FIG. 8, the first error diffusion unit according to an embodiment of the present invention first sets a predetermined pixel E as a center pixel. Thereafter, the error components of the pixels B and D neighboring the E pixel, that is, the lower bits of the decimal bits, are multiplied by the error diffusion weights 5/16 and 7/16, respectively, to generate error diffusion coefficient values of neighboring pixels. In addition, the random coefficient generator (not shown) included in the first error diffusion unit generates at least one random coefficient value, that is, the first random coefficient value R1 and the second random coefficient value R2. The error diffusion coefficient value and the random coefficient value of the neighboring pixel are added together with the error component of the center pixel E, that is, the lower bits of the decimal bit. According to the summed value, information on whether the E pixel is raised, '1' or '0' is generated.

As described above, when the error diffusion coefficient value generated from at least one or more neighboring pixels of the predetermined pixel is diffused to the predetermined pixel, the random error value is added to the error diffusion coefficient value to diffuse. As a result, it is possible to prevent the occurrence of randomization and the generation of a constant error diffusion pattern.

That is, when the lower bit is processed according to the first error spreading scheme, the rounding reflected in the upper bit becomes random, which is reflected in the integer bit. In addition, when the upper bits are processed according to the first error spreading scheme, the rounding reflected directly to the integer bits becomes random.

FIG. 9 is a diagram illustrating an operation characteristic of a second error diffusion unit according to an embodiment of the present invention, and FIG. 10 is a diagram illustrating an error diffusion weighted lookup table according to the second error diffusion method of FIG. 9.

9 and 10, the second error diffusion unit of the present invention first sets a predetermined pixel E as a center pixel, and then the error components of pixels A, B, C, and D neighboring the E pixel, That is, the error bits of the neighboring pixels are generated by multiplying the lower bits among the decimal bits by the error diffusion weights a, b, c, and d, respectively. The error diffusion coefficient values of the neighboring pixels are added together with the error component of the center pixel E, that is, the lower bits of the decimal bit. According to the summed value, information on whether the E pixel is raised, '1' or '0' is generated.

At this time, in one embodiment of the present invention, the error diffusion weights a, b, c, and d are assigned according to the gray value of the image signal of the center pixel E. The error spread weights are composed of an error spread weight lookup table having a format as shown in FIG. 10. That is, the lookup table including the information of the error diffusion weights allocated according to the gray value of the E pixel is stored in the error diffusion weighted lookup table storage unit in advance.

As described above, the second error diffusion method uses the error diffusion weights assigned according to the gray value of the image signal of the center pixel to spread the error, thereby causing a fixed tendency in which the rounding occurs according to the gray value of the center pixel. . As described above, in the embodiment of the present invention, the random tendency and the fixed tendency appearing by using the second error spreading method together with the first error spreading method mentioned above have a synergistic effect of the image implementation. That is, it is possible to suppress the flicker phenomenon and the distortion of the image, and to improve the gray scale expressive power as an even multi-gradation representation of the image is realized.

11 illustrates a plurality of error diffusion weighted lookup tables according to an embodiment of the present invention.

As illustrated in FIG. 11, at least two error spread weighted lookup tables, that is, lookup table A (LUT A) and lookup table B (LUT B), are used alternately in units of frames. The error diffusion weight of the lookup table is determined experimentally in consideration of the image quality effect according to each gray value. The sum of the error diffusion weights a, b, c and d is one. As described above, by using a plurality of lookup tables having different information of error diffusion weights in order for each frame, the gray scale expression power can be further improved.

12 is a view for explaining an error diffusion direction according to an embodiment of the present invention.

As shown in FIG. 12, at least one of the first error diffusion unit and the second error diffusion unit according to an embodiment of the present invention diffuses the error diffusion coefficient values between neighboring pixels in a random direction.

The odd lines and the even lines apply differently to the diffusion direction of the error diffused in the pixel. For example, odd lines spread error diffusion coefficient values from left to right, and even lines spread error diffusion coefficient values from right to left. That is, the sum of the error components of the A, B, C, and D cells is diffused in the E cells, and the sum of the error components of the A ', B', C ', and D' cells is diffused in the E 'cells. At this time, if the sum of the error components diffused into the cell of E or E 'has a value larger than 1, it raises the position. The fractional bits remaining in the rounding are spread back to neighboring pixels.

As described above, in the exemplary embodiment of the present invention, by varying the error diffusion direction in units of lines, it is possible to suppress a constant error diffusion pattern according to the unidirectionality of the difference diffusion. Preferably, by setting the error diffusion direction randomly along the line or the cell, the error diffusion pattern can be reduced more efficiently.

13 is a view for explaining an error diffusion method according to another embodiment of the present invention.

As shown in FIG. 13, in another embodiment of the present invention, the upper and lower bits of the decimal bit are divided into at least one or more bit units, and the divided bits are subjected to error diffusion. For example, as shown in FIG. 13, the fractional bits are divided into three units of upper, middle, and lower bits, and different error diffusion methods are used. You can divide more bit units. In addition, the error diffusion method may use the same error diffusion method except for bits in neighboring units. For example, the upper bits perform the first error spreading method, the middle bits perform the second error spreading method, and the lower bits perform the error spreading using the third error spreading method. As a result, error diffusion can be performed more precisely, and the flicker phenomenon can be reduced.

As such, the technical configuration of the present invention described above can be understood by those skilled in the art that the present invention can be implemented in other specific forms without changing the technical spirit or essential features of the present invention.

Therefore, the exemplary embodiments described above are to be understood as illustrative and not restrictive in all aspects, and the scope of the present invention is indicated by the following claims rather than the detailed description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

As described above, the present invention improves the plasma display device and the image processing method thereof, and therefore, there is an effect of suppressing noise and flicker displayed on the screen during driving.

In addition, the present invention has an effect of improving the gray scale expression power by improving the plasma display device and the image processing method thereof.

In addition, the present invention has the effect of preventing distortion of the image to be implemented by improving the plasma display device and the image processing method thereof.

Claims (16)

An inverse gamma correction unit configured to inversely gamma correct an image signal input from the outside; The rounding caused by error diffusion of the lower bits among the decimal bits of the inverse gamma corrected image signal is reflected in the upper bits of the decimal bits, and the upper bits of the fractional bits are error spread in a different error diffusion method than the lower bits. An error diffusion unit for reflecting the shifting generated by the integer bit of the video signal; And A subfield mapping unit for mapping the error spread image signal to a subfield mapping table Plasma display device comprising a. The method of claim 1, The error diffusion unit A first error spreader which randomly spreads any one of the upper and lower bits using a random coefficient value; And a second error diffusion unit configured to error-diffuse the remaining bits of the upper bit or the lower bit by using an error diffusion weight assigned to the gray value of the image signal. The method of claim 2, The first error diffusion unit And when the error diffusion coefficient value generated from at least one neighboring pixel of a predetermined pixel is diffused into the predetermined pixel, the random coefficient value is added to the error diffusion coefficient value to diffuse. The method of claim 2, The second error diffusion unit And at least one error diffusion weighted lookup table storage, in which error diffusion weights allocated according to the grayscale value are stored in advance. The method of claim 2, At least one of the first error diffusion unit and the second error diffusion unit diffuses the error coefficient values between pixels adjacent to each other in a random direction. The method of claim 1, And the upper bit is 1 bit or more and 3 bits or less from the most significant part of the decimal bit. The method of claim 6, And the lower bit is 1 bit or more and 4 bits or less from the bit consecutive to the higher bit. The method of claim 1, The error diffusion unit And dividing the upper and lower bits into at least one bit unit and error spreading the divided bits. An inverse gamma correction step of inversely gamma correcting an image signal input from the outside; The rounding caused by error diffusion of the lower bits among the decimal bits of the inverse gamma corrected image signal is reflected in the upper bits of the decimal bits, and the upper bits of the fractional bits are error spread in a different error diffusion method than the lower bits. An error diffusion step of reflecting the generated rounding to an integer bit of the video signal; And A subfield mapping step of mapping the error spread image signal to a subfield mapping table Image processing method of a plasma display device comprising a. The method of claim 9, The error diffusion step A first error spreading method of randomly spreading any one of the upper and lower bits using a random coefficient value; And a second error diffusion method of error spreading the remaining bits of the upper or lower bits by using an error diffusion weight assigned to the gray level of the image signal. The method of claim 10, The first error diffusion method And when the error diffusion coefficient value generated from at least one neighboring pixel of a predetermined pixel is diffused into the predetermined pixel, the random coefficient value is added to the error diffusion coefficient value to diffuse the plasma display device. Image processing method. The method of claim 10, The second error diffusion method And storing at least one error diffusion weighted lookup table in which the error diffusion weights allocated in accordance with the grayscale value are stored in advance. The method of claim 10, At least one of the first error diffusion method and the second error diffusion method spreads the error coefficient values between pixels neighboring each other in a random direction. The method of claim 9, And the upper bit is 1 bit or more and 3 bits or less from the most significant part of the decimal bit. The method of claim 14, And the lower bit is 1 bit or more and 4 bits or less from the bit consecutive to the higher bit. The method of claim 10, The error diffusion step And dividing the upper bits and lower bits into at least one bit unit and error spreading the divided bits.

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