KR20050050888A - A driving apparatus of plasma display panel, a method for processing pictures on plasma display panel and a plasma display panel - Google Patents

Abstract

The present invention relates to a driving apparatus for a plasma display panel capable of reducing pseudo contours and high speed operation, and an image processing method for a plasma display panel. First, each frame of the input video signal is separated into at least two independent subframes. Then, the degree of pseudo contour generation is determined by determining whether the separated at least two independent subframe data are each in the edge region and whether they are motion images. In this case, the independent partial frame data gradation conversion range currently input is changed to reduce pseudo contours according to the degree of pseudo contour generation. When there are many pseudo contours, the gradation conversion range for converting the light emission patterns to be similar is increased. In addition, an error spread is applied to each of at least two independent subframes using the grayscale transformed result, and each of them applies an error spread by partially mixing the propagated errors. As a result, pseudo contours can be reduced more precisely, and a high-speed error diffusion process and a high frequency component are improved on a large number of pixels in a high resolution image display device, thereby providing an image having improved image quality.

Description

A driving apparatus for a plasma display panel, an image processing method for a plasma display panel, and a plasma display panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus for a plasma display panel (PDP) and an image processing method for a plasma display panel, and more particularly, to an apparatus for driving a plasma display panel capable of reducing pseudo contours and high speed operation, and an image processing for a plasma display panel. It is about a method.

Recently, flat display devices such as a liquid crystal display (LCD), a field emission display (FED), and a plasma display panel have been actively developed. Among these flat panel display devices, the plasma display panel has advantages of higher luminance and luminous efficiency and wider viewing angle than other flat panel display devices. Therefore, the plasma display panel is in the spotlight as a display device to replace a conventional cathode ray tube (CRT) in a large display device of 40 inches or more.

A plasma display panel is a flat panel display device that displays characters or images using plasma generated by gas discharge, and tens to millions or more of pixels are arranged in a matrix form according to their size. The plasma display panel is classified into a direct current type and an alternating current type according to a shape of a driving voltage waveform applied and a structure of a discharge cell.

In the DC plasma display panel, the electrode is exposed without the discharge space insulated, so that the current flows in the discharge space while the voltage is applied, and there is a disadvantage in that a resistance for current limitation must be made. On the other hand, in the AC plasma display panel, since the electrode covers the dielectric layer, the current is limited by the formation of a natural capacitance component, and the electrode is protected from the impact of ions during discharge.

In general, the driving method of the AC plasma display panel includes a reset period, an addressing period, and a sustain period.

The reset period is a period of initializing the state of each cell in order to perform an addressing operation smoothly on the cell. The addressing period is an address voltage for a cell (addressed cell) turned on to select a cell that is turned on and a cell that is not turned on in a panel. It is a period of time to perform the operation of accumulating wall charge by applying a. The sustain period is a period in which a discharge is applied to actually display an image in the addressed cells by applying a sustain pulse.

As shown in FIG. 1, the plasma display panel divides one frame (1TV field) into a plurality of subfields and controls the time division to implement grayscale. Each subfield consists of the reset period, the addressing period and the sustain period described above. 1 illustrates a case where one frame is divided into eight subfields to implement 256 gray levels. Each subfield SF1-SF8 consists of a reset period (not shown), an address period A1-A8, and a sustain period S1-S8, and the sustain periods S1-S8 are light emission periods 1T, 2T. , 4T, ..., 128T) becomes 1: 2: 4: 8: 16: 32: 64: 128.

At this time, for example, in order to implement a gray scale of 3, the discharge cell is discharged in the subfield SF1 having the 1T light emission period and the subfield SF2 having the 2T light emission period so that the sum of the discharge periods is 3T. In this manner, 256 grayscale images are displayed by combining subfields having different light emission periods.

However, pseudo contours occur due to human visual characteristics when displaying moving images by the subfield method as described above. 2 is a diagram illustrating an example in which a pseudo contour occurs in detail. When the image having the gradation 127 and the gradation 128 side by side moves at a speed of 1 to the right may be represented as shown in FIG. 2 by the subfield arrangement as shown in FIG. 1. At this time, the human vision causes the gray level to be recognized in the direction of the arrow as shown in FIG. Therefore, there is a problem that pseudo contour such as gradation 255 occurs between gradation 127 and gradation 128.

In addition, an error diffusion method is used to compensate for the small number of gradations that can be displayed compared to the number of gradations to be displayed in various image display devices such as a plasma display panel (PDP), a liquid crystal display (LCD), and an organic electroluminescence (EL). This is mainly used. In particular, in the PDP, an error diffusion method is widely used for inverse gamma correction or pseudo contour reduction. Such an error diffusion method is a method of displaying an gray scale to be expressed on an average within a predetermined area by propagating an error generated between a gray scale that can be expressed in an image display and a gray scale to be expressed to surrounding pixels.

Conventional error diffusion methods include Korean Patent Laid-Open Publication No. 2002-18900, "Gamma Correction Apparatus and Method in Plasma Display Panel."

3 is a diagram illustrating an example in which a conventional error diffusion method for inverse gamma correction is applied to driving a plasma display panel.

As shown in FIG. 3, in the conventional plasma display, when an analog video signal is input 10, an n-bit signal (A / D (Analog / Digital) conversion 20) converts the analog signal into a digital signal. 30) and output. At this time, since the A / D-converted output is output by one pixel, the pixel output frequency is 60 × n × m (Hz) in the NTSC (National Television Standard Committee) method of 60 Hz. The size of the output frame is horizontal x vertical = n x m.

As described above, the A / D-converted signal is subjected to the inverse gamma correction 40 to compensate for the gamma correction performed for display in the cathode ray tube (CRT). Thereafter, the inverse gamma corrected signal is output 60 to the PDP, and displayed as a corresponding image by applying a conventional error diffusion 50 to correct the gradation lost when converted to the gradable representation in the PDP.

On the other hand, in recent years, the resolution of an image display device has increased in order to display a high quality image, and the number of frames to be displayed per second has increased. As described above, while the number of pixels to be processed in a limited time increases due to the development of the image display device, the conventional error diffusion method has a problem in that real-time error diffusion processing is difficult because the error diffusion is processed by one pixel.

Therefore, in the case of a high quality image display device, as the number of pixels to be processed in a limited time increases, an error diffusion method for high speed operation is required.

SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the above problems of the related art, and to provide a driving apparatus for a plasma display panel and an image processing method for a plasma display panel capable of reducing pseudo contours and operating at high speed.

A driving apparatus of a plasma display panel according to a feature of the present invention for achieving the above object is

Each frame of the input video signal is divided into at least two independent first and second frames to determine whether the data of the first and second subframes that are output are in the edge region and whether they are motion images. Pseudo contour detection unit for detecting the degree of contour generation;

When it is detected that the pseudo contour is generated by the pseudo contour detector, the gray level of the data of the first and second subframes is adjusted so that the light emission pattern is similar to the data of the first and second subframes previously input and separated. A gray value converter for converting; And

The difference between the gradation of the image signal data output from the gradation value converter and the gradation of the input image signal data of the first and second sub-frames is propagated to surrounding pixels, thereby spreading the error for each of the first and second sub-frames. It includes an error diffusion unit.

The image processing method of the plasma display panel according to another aspect of the present invention

An image of the plasma display panel which displays an image corresponding to the image signal by dividing an image of each field displayed on the plasma display panel in response to an input image signal into a plurality of subfields, and displaying a gray scale according to the combination of the subfields. In the processing method,

(a) dividing each frame of the input video signal into at least two independent first and second subframes;

(b) detecting a pseudo contour occurrence degree by determining whether data of the first and second sub-frames separated in the step (a) are in an edge region and a motion image, respectively;

(c) If it is detected in step (b) that a pseudo contour occurs, the video signal of the first and second subframes is similar to the light emission pattern and the first and second subframe data previously input and separated. Converting the gray levels of the data, respectively; And

(d) The difference between the gray scales converted in the step (c) and the gray scale data of the first and second sub-frames separated in the step (a) is propagated to the surrounding pixels so that the first and second sub-frames Each error diffusing step.

Plasma display panel according to another aspect of the present invention

A plasma panel including first and second electrodes formed on a first substrate, and a third electrode intersecting the first and second electrodes and formed on a second substrate;

A driver for applying a sustain pulse required to drive the first and second electrodes; And

And a control unit which applies a control signal to the driver to divide one frame into a plurality of subfields and to control the number of the subfields forming the one frame and the number of the sustain pulses allocated to each subfield,

The control unit,

Each frame of the input video signal is divided into at least two independent first and second frames to determine whether the data of the first and second subframes that are output are in the edge region and whether they are motion images. Pseudo contour detection unit for detecting the degree of contour generation;

When it is detected that the pseudo contour is generated by the pseudo contour detector, the gray level of the data of the first and second subframes is adjusted so that the light emission pattern is similar to the data of the first and second subframes previously input and separated. A gray value converter for converting; And

The difference between the gradation of the image signal data output from the gradation value converter and the gradation of the input image signal data of the first and second sub-frames is propagated to surrounding pixels, thereby spreading the error for each of the first and second sub-frames. It includes an error diffusion unit.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention. Like parts are designated by like reference numerals throughout the specification.

A driving apparatus of a plasma display panel and an image processing method of the plasma display panel according to an exemplary embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

4 is a schematic plan view of a plasma display panel according to an embodiment of the present invention.

As shown in FIG. 4, the plasma display panel according to the exemplary embodiment of the present invention includes a plasma panel 100, an address driver 200, a scan / sustain driver 300, and a controller 400.

The plasma panel 100 includes a plurality of address electrodes A1-Am arranged in the column direction, and a plurality of scan electrodes Y1-Yn and sustain electrodes X1-Xn arranged in a zigzag pattern in the row direction. . The address driver 200 receives an address drive control signal from the controller 400 and applies a display data signal for selecting a discharge cell to be displayed to each address electrode A1-Am. The scan / hold driver 300 receives a control signal from the controller 400 and alternately inputs a sustain voltage to the scan electrodes Y1-Yn and the sustain electrodes X1-Xn to perform sustain discharge for the selected discharge cell. .

The controller 400 receives R, G, and B image signals and a synchronization signal from the outside, divides one frame into several subfields, and divides each subfield into a reset period, an address period, and a sustain discharge period to drive the plasma display panel. do. At this time, the controller 400 adjusts the number of sustain pulses in each sustain period of the subfield in one frame and supplies the necessary control signals to the address driver 200 and the scan sustain driver 300.

Hereinafter, the controller 400 according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 5 to 18.

5 is a schematic block diagram of a controller 400 of a plasma display panel according to an exemplary embodiment of the present invention.

 As shown in FIG. 5, the control unit of the plasma display panel according to the embodiment of the present invention includes an A / D converter 410, first and second pseudo contour detection units 420 and 422, and first and second frame memory units. 450 and 452, a first gray value conversion and error diffusion unit 430, a second gray value conversion and error diffusion unit 432, and first and second subfield generation units 440 and 442.

The A / D converter 410 converts an input analog video signal into a digital video signal and outputs the same, but simultaneously converts two consecutive pixels simultaneously when converting the digital video signal. Therefore, when the video signal corresponding to one frame is converted and output by the A / D converter 410, two independent frame data (frame 1 and frame 2) having half the size of one frame are formed. At this time, the size of each frame 1 and frame 2 is horizontal x vertical = n / 2 x m.

As described above, since two consecutive pixels are simultaneously output from the A / D converter 410, the pixel frequency is 60 × (1/2) × n × m in the NTSC system of 60 Hz, which is 1/2 of the conventional processing frequency. This decreases to facilitate the real-time calculation.

FIG. 6 is a diagram showing the configuration of two frame data (frame 1 and frame 2) shown in FIG. 5, (a) is a frame data configuration input to the A / D converter 410, (b) and (c) shows two frame data configurations output from the A / D converter 410.

As shown in FIG. 6, when two consecutive pixels in the entire frame data input to the A / D converter 410 are represented as E (Even) pixels and O (Odd) pixels, the A / D converter 410 is represented. Two frame data formed by simultaneously outputting two consecutive pixels through the frame are even (even) pixel frames (frame 1), which is a set of E pixels in even columns, and odd (pixels), a set of O pixels, in odd columns. It is formed independently of the frame (frame 2).

The input image signal of one frame formed as described above is separated into an even (even) pixel frame (frame 1) and an odd (odd) pixel frame (frame 2) to independently perform pseudo contour detection process, gray level conversion, and error diffusion. It will be described in detail below. At this time, the first and second pseudo contour detection units 420 and 422, the first gray value conversion and error diffusion unit 430, the second gray value conversion and error diffusion unit 432, and the first and second subfields are generated. The parts 440 and 442 are different in that they perform pseudo contour detection, gray level conversion, and error diffusion for even and odd pixel frames, respectively, and the method will be described below.

The first and second pseudocontour detectors 420 and 422 respectively input data of two frames (i.e., frame 1 and frame 2) independently formed by the A / D converter 410, respectively, and convert gray level values. Even (even) pixel frame and odd, respectively, using data of two frames independently formed by applying error diffusion (that is, output values of the first and second gray value conversion and error diffusion units 430 and 432) Video pseudo contour information of (odd) pixel frames is detected. At this time, the image data of the previous frame should be stored in order to compare the image of the current frame and the previous frame by using the image data of two frames which are continuously input. The first and second frame memory units 450, 452 is independently formed by the A / D converter 410 to store the two previous frame data to which the gray value conversion and error diffusion are applied. 5 shows that the first and second frame memory units 450 and 452 store frame data of the output values of the first and second gray value conversion and error diffusion units 430 and 432, respectively. This is because the value to which the gray scale conversion and the error diffusion are applied is actually applied to the plasma panel 100. However, in some cases, the first and second frame memories 450 and 452 are two previous frame data independently formed by the A / D converter 410 (ie, frame 1 and frame 2). The first and second pseudo contour detectors 420 may be used to detect pseudo contours, respectively, by storing them. That is, the first frame memory unit 430 may store the previous even pixel frame data, and the second frame memory unit 432 may store the previous odd pixel frame data.

The first and second pseudo contour detectors 420 and 422 detect a pseudo contour level by determining a region having a smooth gray level change and a region having a motion in order to detect the pseudo contour. In this case, whether there is motion is used by using the previously formed even pixel frame and the odd pixel frame stored in the first and second frame memory units 432, respectively.

The first and second pseudo contour detection units 420 and 422 perform edge detection calculations to determine a smooth gray level change. Pseudo contouring occurs in gray scales in which the gradation change is not severe and the light emission pattern is different. Therefore, the degree of pseudo contour is detected by detecting whether there is an edge, that is, a boundary portion. Edge detection is possible through a filtering process. FIG. 7 is a diagram illustrating an example of a 3 × 3 filter. The two 3x3 filters shown in FIG. 7 show an example, and the values can be changed by those skilled in the art. Here, an edge filtering operation is performed using a filter as shown in FIG. 7, and the edge area is determined by comparing the result with an edge moon turn value. That is, the first and second pseudo contour detection units 420 and 422 perform the filtering as described above and determine the result as an edge when the result is larger than a predetermined moon turn value.

The first and second pseudo contour detectors 420 and 422 calculate the degree of movement in addition to the edge detection. Since the amount of pseudo contour generated varies depending on the degree of movement, the pseudo contour is calculated according to the degree of movement. Determine whether or not it occurred. The motion detection method determines the motion step by the system of the same position pixels of the previous frame (referring to an even or odd pixel frame) and the current frame (referring to an even or odd pixel frame). If even the system of the same position pixel is calculated, if the system is 0, it is judged as an image without motion, and the magnitude of the motion is determined based on a randomly determined motion moon turn value.

That is, the first and second pseudo contour detection units 420 and 442 finally determine the pseudo contour step through edge detection and motion detection. 8 is a flowchart illustrating a pseudo contour step through edge detection and motion detection described above.

As shown in FIG. 8, first, the first and second pseudo contour detection units 420 and 442 determine whether the edge region is the edge region described above (S100 and S110). When the edge filtering calculation value obtained by the above-described filtering method is larger than the threshold value by comparing with the moon turn value, it is determined that the pseudo contour is hardly generated by judging it as an edge (S110 and S150). That is, since pseudo contours occur a lot in the small part of the system, it is less likely to occur in a region where there is a lot of system such as an edge.

In addition, the motion is determined through the system of the same position pixels in the above-described method, and even the system is larger than the motion threshold and it is determined that the edge region is not an edge region in the step (S100, S110). If it is, it is determined that the possibility of generating a pseudo contour is large, that is, a large number of pseudo contours are generated (S120, S130, and S170). In other words, it is determined that the part where the pseudo contour occurs a lot occurs in the moving area instead of the edge area.

At this time, when calculating the motion, even if the system of the same position pixel is smaller than the Moonturn value and even the system is 0, it is determined that almost no pseudo contour occurs (S130, S140, S150). However, if the system of the same position pixel is smaller than the Moonturn value and even the system is not 0, it is determined as an area having a small pseudo outline (S130, S140, S160).

As described above, in FIG. 8, the method of dividing the pseudo contour degree into three steps has been described, but the pseudo contour degree can be divided into more steps by using the threshold value in several steps, and accordingly, the gradation conversion and error to be described below will be appropriate. Diffusion methods can reduce pseudo contours.

Next, the first gray value conversion and error diffusion unit 430 and the second gray value conversion and error diffusion unit 432 are pseudo contours detected by the first and second pseudo contour detection units 420 and 422, respectively. The gradation value is converted according to the degree, and error diffusion is performed accordingly. Hereinafter, a method of converting grayscale values and a method of performing error diffusion will be described. Since the first gray value conversion and error diffusion unit 430 and the second gray value conversion and error diffusion unit 432 perform the same gray level conversion and the error diffusion, they will be described below.

First, the gray scale value conversion method in the first and second gray scale value conversion and error diffusion units 430 and 432 will be described.

The first and second gray value conversion and error diffusion units 430 and 432 respectively perform the gray level conversion according to the pseudo contour steps detected by the first and second pseudo contour detection units 420 and 422, respectively. In step S150, it is determined that the contour is hardly generated, and in step S160 and S170 in which it is determined that pseudo contours are generated, the gray value is converted. In steps S160 and S170 where it is determined that the pseudo contour is generated, the gradation value converting principle is performed by matching the current frame (frame 1 or the first frame) to match a specific light emission pattern of the previous frame gray level (that is, the light emission pattern of the subfield). The tone of frame 2) is converted.

9 is a diagram illustrating an example of gray level conversion when a previous frame gray level is 102 and a current frame gray level is 106. FIG. According to the subfield weight arrangement shown in FIG. 9, the light emission pattern of the previous frame grayscale 102 is {0011111000} and the light emission pattern of the current frame grayscale 106 is {0111110100}, and the light emission patterns of the subfields sf7 and sf8 having a large weight are different. . In this case, a pseudo contour is generated. In the present invention, the gray scale conversion is performed to convert the current frame gray level from 106 to 105 so that the light emission patterns of the subfields sf6 to sf10 match. That is, when it is determined that a pseudo contour occurs, the gray level is converted so that the gray level value of the current frame matches the specific light emission pattern of the gray level value of the previous frame (subfield light emission patterns having a high weight are made equal). As a result, the light emission patterns of the high-weight subfields become the same, thereby reducing pseudo contours.

In FIG. 9, the case where the light emission pattern can be matched by the change of the gray scale value 1 is shown. However, in order to match the light emission pattern, a large change in the gray scale value may occur. At this time, it is determined whether to convert the gray scale according to the step of generating the pseudo contour outlined in FIG. When the degree of pseudo contour is large, that is, when it is determined that a large number of pseudo contours are generated (S170), the gray level is converted to match the emission pattern even when the gray level value is greatly changed. However, when the degree of pseudo outline is small, that is, when it is determined that less pseudo outline is generated (S160), the gray scale conversion is performed to match the emission pattern within the limited gray scale conversion range. The reason for converting the gray scale value within the limited range as described above is that when the gray scale value conversion is large, the noise caused by this is rather annoying to the human eye.

Meanwhile, the first and second gray value conversion and error diffusion units 430 and 432 perform an error diffusion method to compensate for the error of the gray level generated when the gray value is converted to reduce the pseudo contour as described above. do.

Meanwhile, the first and second gray value conversion and error diffusion units 430 and 432 respectively apply an error diffusion method to the gray value converted data (refer to FIG. 9) to reduce pseudo contours. The coefficient affects the picture quality. In the error diffusion method, an error between gray levels is propagated to surrounding pixels. In this case, the error is divided and propagated by a predetermined weight at a predetermined position when propagating to surrounding pixels. This weight is called an error diffusion coefficient, and a well-known error diffusion coefficient is a Floyd-Steinberg coefficient. The shape of this Floyd-Steinberg coefficient is shown in FIG.

Referring to FIG. 10, a process of separating one frame into even pixel frames and odd pixel frames, which are partial frames, and independently processing the error frames (for example, an error propagation process of each partial frame by applying a Floyd-Steinberg coefficient is described. 11 (a) and 11 (b), and FIG. 11 (c) shows a form displayed on one frame in which error propagation processes applied to two frames are later summed.

As illustrated in FIGS. 11A and 11B, an error propagated to one pixel in each of two frames may be represented by Equations 1 and 2 below.

here , Denotes the sum of errors propagated during processing of (x, y) pixels in the even pixel frame and the odd pixel frame, respectively.

On the other hand, referring to Figure 11 (c), by processing the error for each of the separated frames, the result of the pixel from which the error is propagated for each pixel when viewed in one frame image is generated. FIG. 13 is an image when the independent error diffusion method is applied by configuring two independent frames as shown in FIG. 5 when the 8-bit image illustrated in FIG. 12 is input. As shown in FIG. 13, when an independent error diffusion method is applied to two consecutive pixels, a pixel in which an error propagates becomes farther away for each pixel, resulting in a lower spatial frequency, resulting in a higher frequency component in the image. There is a disadvantage in that a lot of lost images are displayed.

In order to overcome the above disadvantages, the embodiment of the present invention applies a mixed error propagation method as shown in FIG. 14 so that the propagation of the error is partially mixed between the even pixel frame and the odd pixel frame. That is, in FIG. 11C, error propagation in the even pixel frame is performed only between even pixels, and error propagation in the odd pixel frame is performed only between odd pixels. It is not only made between even pixels during propagation, but also mixed with partial errors from adjacent odd pixels, and similarly, it is not only made between odd pixels when propagating errors in odd pixel frames, but also partially errors from adjacent even pixels. Use it. At this time, the pixel propagating the mixed error is located in a line higher than the pixel to which the propagated error is applied and is an adjacent pixel.

The mixed error propagation method illustrated in FIG. 14 may be represented by the following Equations 3 to 10.

here, Is the (x, y) th input pixel of the even pixel frame, Is the (x, y) th input pixel of the odd pixel frame, Is the (x, y) th input pixel of the evenly propagated even pixel frame, Is the (x, y) th input pixel of the error propagated odd pixel frame, Is an error propagated to the (x, y) th pixel of the even pixel frame, Is an error propagated to the (x, y) th pixel of the odd pixel frame, Is an error in (x, y) pixels of the even pixel frame, Is an error in (x, y) pixels of odd pixel frame, Is the (x, y) pixel output gradation of an even pixel frame, Is the (x, y) pixel output gradation of the odd pixel frame, Is a bit reduced output gray scale determination function.

As described above, when the 2-bit output image is calculated for the 8-bit image of FIG. 12 according to the mixed error propagation method according to Equations 3 to 10, the resultant image as shown in FIG. 15 is obtained. . The resultant image of FIG. 15 may provide an improved image quality while expressing a smoother image than the image of FIG. 13 represented by an independent error propagation method.

On the other hand, [Equation 3] to [Equation 10] is a mixed error propagation method according to an embodiment of the present invention is applied to the case of Floyd-Steinberg coefficient shown in Figure 14, the technical scope of the present invention The mixed error propagation method according to the embodiment of the present invention may be applied to other types of error diffusion coefficients without being limited thereto. For example, when an independent error propagation method using an even pixel frame and an odd pixel frame according to an embodiment of the present invention is used with respect to the Fan coefficient shown in FIG. 16, FIGS. 17A and 17B are attached. The error propagates as shown in On the other hand, as shown in (c) of FIG. 17, when all independent error propagation is displayed for one frame image, the error propagation region is far from each other, resulting in deterioration of image quality. In order to overcome this, the hybrid error propagation method according to an embodiment of the present invention can be applied to the Fan coefficient, and the error can be propagated as shown in FIG. 18. Such a mixed error propagation process can be represented using the following Equations 11 and 12 instead of Equations 1 and 2.

Through the above method, the first and second gray value conversion and error diffusion units 430 and 432 respectively perform error diffusion.

Meanwhile, in FIG. 5, the first and second gray value conversion and error diffusion units 430 and 432 are shown as blocks that simultaneously perform gray level conversion and error diffusion. However, unlike FIG. 5, the gray level value conversion and error diffusion are separated. It can be realized through blocks. That is, the first and second gray value conversion and error diffusion units 430 and 432 may be separated together with the first and second gray value conversion units and the first and second error diffusion units, respectively. Same as described.

  The first subfield generation unit 440 generates a subfield corresponding to the image signal data output from the first gray value conversion and error diffusion unit 430. That is, on / off of each subfield (meaning each subfield having a luminance weight differently) corresponding to the image signal data that is converted by the first grayscale value conversion and error diffusion unit 430, and the error diffusion is output. To generate a subfield.

In addition, the second subfield generator 442 generates a subfield corresponding to the image signal data output from the second gray value conversion and error diffusion unit 432. That is, on / off of each subfield (meaning each subfield having different luminance weight) in response to the image signal data that is converted by the second grayscale value conversion and error diffusion unit 432 and outputted with error diffusion. To generate a subfield.

The subfield data output from the first and second subfield generators 440 and 442, respectively, is summed into one frame of data again to be displayed on the plasma display panel, so that the PDP driver 500, that is, the address driver 200 may be combined. And the scan / hold driver 300 to be displayed on the plasma display panel 100.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

For example, in the above description, only one frame is divided into an even pixel frame and an odd pixel frame, and only the application of the mixed error diffusion in error diffusion for each is described. However, the technical scope of the present invention is not limited thereto. By dividing into three or more frames, a mixed error spread can be applied when the error spreads for each. In this case, similarly to the error mixing diffusion method illustrated in FIG. 18, the present invention may be applied to a case in which three or more frames are separated by mixing independent errors. It will be easily understood by those skilled in the art.

As described above, according to the present invention, it is possible to reduce the pseudo contour more precisely by determining whether or not the pseudo contour is generated and varying the range of gray value conversion to make the light emission pattern similar according to the degree of pseudo contour. By dividing and processing one frame into two or more independent frames, high-speed error diffusion processing is possible on a large number of pixels of data in a high resolution image display device.

In addition, by mixing errors of the even pixel frame and the odd pixel frame during error propagation, the high frequency component may be further improved to provide an image having an improved image quality.

1 is a diagram illustrating a gray scale display method of a plasma display panel.

2 is a diagram illustrating an example in which a pseudo contour occurs.

3 is a diagram illustrating an example in which a conventional error diffusion method for inverse gamma correction is applied to driving a plasma display panel.

4 is a schematic plan view of a plasma display panel according to an embodiment of the present invention.

5 is a schematic block diagram of a controller of a plasma display panel according to an exemplary embodiment of the present invention.

FIG. 6 is a diagram showing the configuration of two frame data shown in FIG. 5, (a) is a frame data configuration input to an A / D converter, and (b) and (c) are output from an A / D converter. It consists of two frame data.

7 is a diagram illustrating an example of a 3x3 filter used for detecting edge detection.

8 is a flowchart illustrating a pseudo contour step through edge detection and motion detection.

9 is a diagram illustrating an example of gray level conversion when a previous frame gray level is 102 and a current frame gray level is 106. FIG.

10 is a view showing the shape of the Floyd-Steinberg coefficient, which is a general error diffusion coefficient.

FIG. 11 is a diagram illustrating an error propagation process of each subframe by applying a Floyd-Steinberg coefficient, (a) for even pixel frames, (b) for odd pixel frames, and (c) overall error It is about the radio wave processing process.

12 illustrates an 8-bit test image.

FIG. 13 illustrates a resultant image after the independent error propagation process illustrated in FIG. 11 is applied.

14 is a diagram in which a mixed error propagation process according to an embodiment of the present invention is applied by Floyd-Steinberg coefficient.

FIG. 15 illustrates a resultant image after the mixed error propagation process illustrated in FIG. 14 is applied.

16 is a view showing the shape of the FAN coefficient which is a general error diffusion coefficient.

17 is a diagram in which an independent error propagation process is applied by FAN coefficients, (a) is for even pixel frames, (b) is for odd pixel frames, and (c) is for overall error propagation processing. .

18 is a diagram illustrating a mixed error propagation process applied by a FAN coefficient according to an embodiment of the present invention.

Claims (18)

Each frame of the input video signal is divided into at least two independent first and second frames to determine whether the data of the first and second subframes that are output are in the edge region and whether they are motion images. Pseudo contour detection unit for detecting the degree of contour generation; When it is detected that the pseudo contour is generated by the pseudo contour detector, the gray level of the data of the first and second subframes is adjusted so that the light emission pattern is similar to the data of the first and second subframes previously input and separated. A gray value converter for converting; And The difference between the gradation of the image signal data output from the gradation value converter and the gradation of the input image signal data of the first and second sub-frames is propagated to surrounding pixels, thereby spreading the error for each of the first and second sub-frames. An apparatus for driving a plasma display panel including an error diffusion unit. The method of claim 1, And the error diffusion unit partially spreads the mutually propagated errors for each of the independent first and second subframes, and applies an error diffusion. The method according to claim 1 or 2, The pseudo contour detection unit A first pseudo contour detector for detecting a pseudo contour generation degree by determining whether the separated partial output data of the first subframe is in an edge region and a motion image signal; And a second pseudo contour detector for detecting the degree of pseudo contour generation by determining whether the data of the separated second frame is in the edge region and the motion image signal. The method according to claim 1 or 2, The gray value conversion unit When the data of the first subframe is detected by the pseudo contour detection unit to generate a pseudo contour, the data of the first subframe is similar to the data of the first subframe previously input and separated so that the light emission pattern is similar. A first gray value converter for converting gray levels; When the data of the second sub-frame is detected by the pseudo contour detecting unit as generating a pseudo contour, the data of the second sub-frame is similar to the data of the second sub-frame previously input and separated so that the emission pattern is similar. And a second gray value converter for converting gray levels. The method according to claim 1 or 2, A first error diffusion unit which propagates a difference between the gray level of the image signal data of the first subframe and the gray level of the input image signal data of the first subframe to the surrounding pixels by error diffusion; And a second error diffusion unit configured to propagate a difference between the gray level of the image signal data of the second sub-frame and the gray level of the input image signal data of the second sub-frame to the surrounding pixels by error diffusion. Driving device of the plasma display panel. The method according to claim 1 or 2, And the pseudo-contour detecting unit detects whether the edge region is the edge region by comparing the result of the calculation using a filtering filter with an arbitrarily determined edge moon turn value. The method according to claim 1 or 2, The pseudo contour detection unit detects whether the motion image of the same position pixel is compared with the motion threshold value in the first and second subframes currently input and the previously input first and second subframes, whether the motion image is the motion image. A drive device for a plasma display panel. The method according to claim 1 or 2, The gradation value converting unit enlarges the range of gradation values so that the light emission pattern is similar when the pseudo contour generation degree detected by the pseudo contour detection unit is large, and when the pseudo contour generation degree is small, the emission pattern is similar. And a range of gradation values to be converted so as to be reduced. The method according to claim 1 or 2, And the gray value converting unit converts the gray scale values so that the light emitting patterns of the high-weight subfields become similar in converting the gray scale values so that the light emitting patterns become similar. The method according to claim 1 or 2, When the input video signal is an analog video, each frame of the input analog video signal is divided into at least two independent first and second sub-frames and converted into a digital video signal output to the pseudo contour detector by analog / The driving apparatus of the plasma display panel further comprising a digital converter. The method according to claim 1 or 2, In the at least two independent first and second subframes, the first subframe is an odd frame that is a set of pixels located in odd columns within one frame, and the second subframe is within one frame. And an even subframe, which is a set of pixels located in even columns. The method of claim 1, And a subfield generator for generating subfields corresponding to data output by error diffusion in the error diffusion unit. An image of the plasma display panel which displays an image corresponding to the image signal by dividing an image of each field displayed on the plasma display panel in response to an input image signal into a plurality of subfields, and displaying a gray scale according to the combination of the subfields. In the processing method, (a) dividing each frame of the input video signal into at least two independent first and second subframes; (b) detecting a pseudo contour occurrence degree by determining whether data of the first and second sub-frames separated in the step (a) are in an edge region and a motion image, respectively; (c) If it is detected in step (b) that a pseudo contour occurs, the video signal of the first and second subframes is similar to the light emission pattern and the first and second subframe data previously input and separated. Converting the gray levels of the data, respectively; And (d) The difference between the gray scales converted in the step (c) and the gray scale data of the first and second sub-frames separated in the step (a) is propagated to the surrounding pixels so that the first and second sub-frames And an error diffusion step, respectively. The method of claim 13, The error diffusion in the step (d) is an error diffusion applied by partially mixing the mutually propagated errors for each of the independent first and second subframes. The method according to claim 13 or 14, And detecting the presence or absence of the edge region in the step (b) by comparing the result of the calculation using a filtering filter with an arbitrarily determined edge moon turn value. The method according to claim 13 or 14, In the step (b), whether or not the motion image is detected by comparing the system of the same position pixel with the motion threshold in the first and second subframes currently input and the first and second subframes previously input. An image processing method of a plasma display panel. The method according to claim 13 or 14, In the case of the step (c), the conversion of the gradation increases the range of the gradation value for converting the light emission patterns to be similar when the pseudo contour generation degree detected in the step (b) is large, and when the pseudo contour generation degree is small. And a range of gray scale values for converting the light emission patterns to be similar to each other is small. A plasma panel including first and second electrodes formed on a first substrate, and a third electrode intersecting the first and second electrodes and formed on a second substrate; A driver for applying a sustain pulse required to drive the first and second electrodes; And And a control unit which applies a control signal to the driver to divide one frame into a plurality of subfields and to control the number of the subfields forming the one frame and the number of the sustain pulses allocated to each subfield, The control unit, Each frame of the input video signal is divided into at least two independent first and second frames to determine whether the data of the first and second subframes that are output are in the edge region and whether they are motion images. Pseudo contour detection unit for detecting the degree of contour generation; When it is detected that the pseudo contour is generated by the pseudo contour detector, the gray level of the data of the first and second subframes is adjusted so that the light emission pattern is similar to the data of the first and second subframes previously input and separated. A gray value converter for converting; And The difference between the gradation of the image signal data output from the gradation value converter and the gradation of the input image signal data of the first and second sub-frames is propagated to surrounding pixels, thereby spreading the error for each of the first and second sub-frames. Error diffusion unit Plasma display panel comprising a.