KR100480165B1 - Apparatus And Method For Driving Plasma Display Panel Using An Enlarging Method Of Dynamic Range - Google Patents

Abstract

The present invention relates to an apparatus and method for driving a plasma display panel using a dynamic range enlargement method for improving contrast of a display screen.

The driving apparatus of the plasma display panel using the dynamic range expansion method according to the present invention is a frame memory for storing moving image data input from an external input line in units of frames, and is connected in series with the frame memory and has a minimum distribution of lower and upper gray levels. The minimum distribution lower and upper gray levels smaller than the threshold are removed when the value is greater than or equal to the preset threshold, and when the movement between the previous and current frames is greater than or equal to the predetermined threshold, the minimum and lower gray levels are removed. Dynamic range adjusting unit for converting the dynamic range of moving picture data, and plasma display panel driver for controlling and supplying the corrected image data signal of which the dynamic range is expanded by being connected in series to the dynamic range adjusting unit. A motion amount detection unit connected in parallel with the frame memory between the input line and the dynamic range adjustment unit to detect the motion amount between the previous and current frames, and a minimum amount during one frame connected in parallel with the frame memory between the input line and the dynamic range adjustment unit. Minimum and minimum gray level detectors for detecting the lower and upper gray levels of the distribution, and the smallest and lowest gray levels detected in series and connected to the minimum and lower gray level detectors, and the dynamic range adjuster in series. And a minimum distributed lower gray level determination unit for determining a relationship.

Description

Apparatus And Method For Driving Plasma Display Panel Using An Enlarging Method Of Dynamic Range}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to an apparatus and method for driving a plasma display panel using a dynamic range enlargement method for improving contrast of a display screen through expansion of a dynamic range during moving image display.

Plasma Display Panel (hereinafter referred to as "PDP") is a display device using visible light generated from a phosphor when ultraviolet light generated by gas discharge excites the phosphor. PDP is thinner and lighter than Cathode Ray Tube (CRT), which has been the mainstay of display means, and has the advantage of realizing high definition / large screen.

The PDP has an upper substrate and a lower substrate which are installed to face each other with partition walls therebetween. The upper substrate includes a scan electrode and a sustain electrode formed in a direction crossing the partition wall. The lower substrate includes an address electrode formed in a direction parallel to the partition wall, and a dielectric layer formed to cover the address electrode. The discharge cell is positioned at the intersection of the scan electrode, the sustain electrode and the address electrode.

The PDP is driven by dividing one frame into several subfields having different emission counts in order to realize gray levels of an image. Each subfield is divided into a reset period for uniformly causing discharge, an address period for selecting a discharge cell, and a sustain period for implementing gray scale according to the number of discharges.

In the address period, scan pulses are supplied to the scan electrodes, and data pulses synchronized with the scan pulses are supplied to the address electrodes. At this time, an address discharge occurs in the discharge cell supplied with the scan pulse and the data pulse. After the scan pulses are supplied to all the scan electrodes, the sustain pulses are alternately supplied to the scan electrodes and the sustain electrodes. When a sustain pulse is supplied to the scan electrode and the sustain electrode, sustain discharge occurs in the discharge cells in which the address discharge has occurred.

When the image is to be displayed in 256 gray levels, the frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields. Here, the reset period and the address period of each subfield are the same for each subfield, while the sustain period and the number of discharges thereof are 2 ⁿ (n = 0,1,2,3,4,5,6,7) in each subfield. , 8). As described above, since the sustain period is changed in each subfield, gray levels of an image can be realized.

The PDP is driven by enlarging the dynamic range of moving images in order to improve contrast.

1 is a block diagram showing a driving apparatus of a PDP using a dynamic range expansion method according to the prior art.

Referring to FIG. 1, a driving apparatus of a PDP using a dynamic range expansion method according to the related art includes a frame memory 14, lower and upper gray level histogram detectors 22A and 22B, minimum distribution lower and upper gray level value determination units. 24A and 24B, the dynamic range adjusting unit 16, and the PDP driving unit 18 are provided.

The frame memory 14 stores the data from the input line 12 in one frame unit and supplies the data to the dynamic range adjusting unit 16.

The histogram detectors 22A and 22B of the lower and upper gray levels detect the histograms of the lower and upper gray levels for each gray level on the basis of the data from the input line 12 by one frame. This first obtains the overall distribution of each gray level for the input screen of one frame. The histogram H (I), which is a gray level distribution value of the input data, is detected based on the overall distribution. At this time, histograms are mainly detected at gray levels, such as about 0 to 20 gray and 220 to 255, to determine minimum and maximum gray levels (MIN and MAX).

The minimum distribution lower and upper gray level value determination units 24A and 24B determine an arbitrarily set reference ratio and determine lower and upper gray levels (MIN, MAX) having less gray level distribution through histograms of detected lower and upper gray levels. do.

The dynamic range adjusting unit 16 enlarges the dynamic range of the input data using the data input from the frame memory 14, the minimum distribution lower and upper gray level values. The dynamic range adjuster 16 supplies input data having an enlarged dynamic range to the PDP driver 18.

The PDP driver 18 corrects the digital signal input from the dynamic range adjuster 16 and supplies it to the panel. To this end, the PDP driver 18 includes the first inverse gamma correction unit 32A, the gain control unit 34, the error diffusion unit 36, the subfield mapping unit 38, and the data alignment unit 40 as shown in FIG. And a second inverse gamma correction unit 32B, an average picture value (APL) unit 44, a waveform generator 46, and a panel 48.

The first and second inverse gamma correction units 32A and 32B perform inverse gamma correction on the video signal input from the dynamic range adjusting unit 16 to linearly convert the luminance value according to the gray value of the image signal.

The APL unit 44 receives the video data corrected by the second inverse gamma correction unit 32B and generates an N-stage signal for adjusting the number of sustain pulses. The gain controller 34 amplifies the video signal corrected by the first inverse gamma correction unit 32A by the effective gain.

The error diffusion unit 36 finely adjusts the luminance value by diffusing an error component of a cell into adjacent cells. The subfield mapping unit 38 reallocates the video data corrected by the error diffusion unit 36 for each subfield.

The data aligner 40 aligns the video signal to be supplied to the panel 48, and supplies the video signal to an address driving integrated circuit (IC) not shown.

The waveform generator 46 generates a timing control signal based on the N-stage signal input from the APL unit 44, and converts the generated timing control signal into an address driver IC, a scan driver IC, and a sustain driver IC of the panel 48. Supply.

In detail, the second inverse gamma correction unit 32B first performs inverse gamma correction on the video signal input from the dynamic range adjustment unit 16 and supplies the inverse gamma correction unit to the APL unit 44. The APL unit 44 receiving the inverse gamma corrected video signal generates an N-stage signal for adjusting the number of sustain pulses, and supplies it to the waveform generator 46. The waveform generator 46 generates a timing control signal using the N-stage signal input from the APL unit 44, and supplies the generated control signal to the address driving IC, the scan driving IC, and the sustain driving IC.

The first inverse gamma correction unit 32A performs inverse gamma correction on the video signal input from the dynamic range adjustment unit 16 and supplies it to the gain control unit 34. The gain control unit 34 receiving the inverse gamma corrected video signal amplifies the corrected video signal by an effective gain and supplies it to the error diffusion unit 36. The error diffusion unit 36 error-spreads the video signal input from the gain control unit 34 to finely adjust the luminance value. The video signal output from the error diffusion unit 36 is input to the subfield mapping unit 38. The subfield mapping unit 38 reallocates the error-diffused video data for each subfield and supplies the data to the data alignment unit 40. The data aligner 40 aligns the video signal and supplies it to the address driver IC.

Thereafter, an image corresponding to the video signal is displayed on the panel 48 by the control of the address driving IC, the scan driving IC, the sustain driving IC, and the like. As described above, in the driving apparatus of the PDP according to the related art, it is possible to obtain a clear image by improving contrast through an enlarged dynamic range.

FIG. 3 is a flowchart illustrating the dynamic range expansion method described with reference to FIG. 1.

Referring to FIG. 3, first, input data RGB from the outside is input to the lower and upper gray level histogram detectors 22A and 22B.

The histogram H (I) of each gray level is detected (S12). This first obtains an overall distribution of gray levels for an input screen of one frame. Based on the overall gray level distribution, the ratio of the histogram, which is the number of distributions of 0 to 255 gray levels, can be known. For example, in a PDP with WVGA (853 * 480) resolution mode, if the number of histograms with 2 grays is 245, the distribution ratio is Becomes When the distribution ratio of each gray level is obtained, the histogram ratio with respect to the input data appears as shown in Tables 1 and 2.

Histogram % Of distribution Hist [0] 0.02 Hist [1] 0.04 Hist [2] 0.06 Hist [3] 0.0 … … Hist [17] 0.03 Hist [18] 0.09 Hist [19] 0.1 Hist [20] One

Histogram % Of distribution Hist [220] 1.0 Hist [221] 0.1 Hist [222] 0.06 Hist [223] 0.001 … … Hist [252] 0.03 Hist [253] 0.02 Hist [254] 0.09 Hist [255] 0.05

Here, the histogram distribution ratio (%) for each gray level may vary depending on the input data for one frame.

Based on the histogram distribution ratio (%), the minimum distribution lower and upper gray levels (MIN, MAX) are determined. (S14) First, before determining the minimum distribution lower and upper gray level values, the threshold value of the histogram distribution ratio (%) is determined. Decide In Figure 3, 0.1% was set as the threshold. As a result, the first gray level with 0.1% or more is determined as the minimum distributed lower gray level (MIN) and the minimum distributed upper gray level (MAX). (S18) When the distribution ratio is 0.1% or less, the next histogram distribution ratio is continuously searched. (S16)

Thus, in the case of Table 1 and Table 2, the gray level is determined as the minimum distributed lower gray level MIN is 19 and the minimum distributed upper gray level MAX is 221.

The values of the minimum distribution lower and upper gray levels MIN and MAX determined as described above are input to the dynamic range adjusting unit 16. The dynamic range adjusting unit 16 rearranges the input image by using Equation 1 to input the minimum distribution lower and upper gray levels MIN and MAX.

Where X is the gray level of the input data before correction and Y is the gray level of the input data after correction. In addition, MAX is the value of the minimum distributed upper gray level, and MIN is the value of the minimum distributed lower gray level.

When X is 40, the minimum distribution lower and upper gray level values determined through Table 1 and Table 2 are applied to Equation 1. By Y, the minimum gray level value after correction for X becomes 26.5. This changes the input data of 40 to a lower value of 26.5. That is, in the present invention, as shown in FIG. 4, the histogram distribution I according to the gray level in the dotted line form may be obtained as the histogram distribution II according to the gray level in the solid line form in which the dynamic range is expanded. As a result, as the dynamic range is enlarged, the contrast of the screen is improved to obtain a clear screen. In other words, the bright part is displayed brighter and the dark part is displayed darker so that the contrast between the bright part and the dark part of the screen can be clearly displayed.

5A and 5B illustrate changes in the display image before and after applying the dynamic range enlargement method. As the contrast of the light and dark of the screen becomes clearer, the dynamic range is enlarged according to the prior art illustrated in FIG. 5B. It can be seen that the image is clearer than that of FIG. 5A.

FIG. 6 is a view for designating a predetermined area for comparing only a part of the display image shown in FIG. 5B, and FIGS. 7A and 7B are views showing a change in histogram distribution after the dynamic range expansion process according to the prior art. FIG. 8B is a diagram illustrating a change of a display image of a portion of FIG. 6.

7A and 7B, the distribution of the histogram according to the prior art of FIG. 7B is toward the gray level lower than the distribution of the histogram according to the prior art of FIG. 7A by expanding the dynamic range according to the minimum distribution lower and upper gray level values. You can see that it has been moved. As a result, as described above, the darker portions become darker and the brighter portions appear brighter.

Referring to the results of FIGS. 7A and 7B through FIGS. 8A and 8B, first, FIGS. 8A and 8B compare regions A of FIG. 6, and it can be seen that a dark portion of the sky becomes darker. Next, FIGS. 9A and 9B compare the area B of FIG. 6 and show a display screen in which a bright part and a dark part coexist. In this case as well, the contrast between the bright and dark areas can be seen that the contrast is improved.

However, in the conventional method of increasing the dynamic range of the PDP, as described above, the bright and dark portions through the dynamic range enlargement are brighter and darker than the original image, and the contrast in the moving image is improved. As a result of the conversion of the original images moved to the portion, a problem of low gradation that cannot be properly expressed in the image occurs.

To illustrate this example, when the minimum distribution upper and lower gray levels MAX of the input image are 250 and 10, respectively, the minimum distribution upper and lower gray levels MAX of the converted image are shown in Table 3 by Equation (1). Are converted together.

Original Image Gray Level Related formula Transform Image Gray Level 11 1/210 * 255 One 12 2/210 * 255 2 13 3/210 * 255 3 … … …

That is, as shown in Table 3, images having gray levels of the original images 11 to 13 are converted into images having gray levels of 1 to 3. After the converted image having the gray levels of 1 to 3 is converted by inverse gamma correction, the image is not represented. That is, after gamma processing, as shown in FIG. 10, the power of expression is lost until about 1 to about 4. As a result, when the images having the gray levels of 11 to 13 enter the 1 to 4 regions, they cannot be represented.

In order to improve the low gradation problem when the dynamic range is expanded, the PDP driving method generally uses error diffusion to improve the expression of the low gradation. Referring to FIG. 11, when gamma correction is performed on the input image of FIG. 11 (a), the result is as shown in FIG. 11 (b). Referring to the gamma correction result corresponding to the gray level of 23 or less in FIG. 11 (b), it can be seen that the value has a value of 0.8 or less that is 1 or less. Deriving the luminance value for the panel of FIG. 11 (c) through the gamma correction values having values of 0.8 or less arranged at predetermined intervals indicates that values between 0 and 8 have the same value as 1.01. This means that gray levels below 8 will be equal to 0 and all will be displayed in the panel as black. As a result, the panel may not display an accurate display for each gray level.

Accordingly, an object of the present invention is to provide an apparatus and method for driving a plasma display panel using a dynamic range enlargement method which improves the contrast of a display screen by preventing the dynamic range enlargement from being less than the gray level without expressive power even through error diffusion. To provide.

Another object of the present invention is to equalize the low gray levels except the gray levels without expressive power through error diffusion, and then to expand the dynamic range to improve the contrast of the display screen. It is to provide a drive device and method.

It is still another object of the present invention to provide an apparatus and method for driving a plasma display panel using a dynamic range magnification method which takes an intermediate value between gamma correction values of gray levels whose dynamic range is expanded to improve contrast of a display screen. There is.

In order to achieve the above object, the driving apparatus of the plasma display panel using the dynamic range expansion method according to the present invention is connected to the frame memory and the frame memory for storing the moving picture data input from the external input line by one frame unit Removes the minimum and lower gray levels smaller than the threshold when the minimum and upper gray levels are above a predetermined threshold; and removes the minimum and lower gray levels when the movement between previous and current frames is greater than or equal to a preset threshold. A dynamic range adjusting unit for converting the dynamic range of the moving image data using a higher gray level and a dynamic range adjusting unit connected to the dynamic range adjusting unit in order to control a corrected image data signal in which the dynamic range is expanded to a panel A movement amount detecting unit connected in parallel with the frame memory between the supplying plasma display panel driver and the input line and the dynamic range adjusting unit to detect a movement amount between a previous and a current frame, and the frame between the input line and the dynamic range adjusting unit Minimum minimum and upper gray level detectors connected in parallel with the memory to detect the minimum and lower gray level levels for one frame, and the minimum detected by being connected in series between the minimum and lower gray level detectors and the dynamic range adjuster. And a minimum distributed lower gray level determination unit that determines a magnitude relationship between the distributed lower gray level and a preset threshold.

In the present invention, the plasma display panel driver includes an inverse gamma correction unit that inversely gamma corrects a video signal via the dynamic range adjustment unit and linearly converts luminance values according to grayscale values of an image signal, and the inverse gamma correction unit. A gain control unit for amplifying the corrected video signal by effective gain, an error diffusion unit for finely adjusting the luminance value by diffusing an error component of the cell into adjacent cells, and the video data corrected from the error diffusion unit for each subfield. And a data alignment unit for aligning the video signal to be supplied to the display panel.

The inverse gamma correction unit of the present invention may further include a gamma correction value adjusting unit which adjusts the linearly converted luminance value by taking an intermediate value of the linearly converted luminance values to increase the expressive power. .

A method of driving a plasma display panel using a dynamic range expansion method according to the present invention includes detecting a motion amount by comparing a previous and current frame with respect to a moving image input image, and performing a minimum distribution lower and upper gray level for the moving image input image. Determining a magnitude and magnitude relationship between the detected motion amount and the detected minimum distribution lower and upper gray levels and a predetermined threshold value; and wherein the detected minimum distribution lower and upper gray levels are the threshold values. Removing the minimum distribution lower and upper gray levels smaller than the threshold if larger, and converting the dynamic range of the input image using the removed minimum distribution lower and upper gray levels if the motion amount is larger than the threshold. It is characterized by including.

The converting of the dynamic range of the input image in the present invention further includes maintaining the dynamic range of the input image when the amount of motion and the detected minimum distribution lower and upper gray levels are smaller than a preset threshold. It features.

In the present invention, the input image from which the gray level smaller than the threshold value is removed is subdivided at regular intervals so that a predetermined region of the minimum distribution lower gray level fills the number of gray levels removed.

The method may further include linearly converting a luminance value according to the grayscale value of the input image in which the dynamic range is enlarged.

The linearly converting the luminance values according to the grayscale values of the input image may include obtaining an intermediate value of the converted luminance values, and the luminance according to the grayscale values of the input image in the array of the intermediate values. And rearranging the values.

Other objects and features of the present invention in addition to the above object will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 12 to 17.

12 is a diagram illustrating a driving device of a PDP using a dynamic range expansion method according to an embodiment of the present invention.

Referring to FIG. 12, a driving device of a PDP using a dynamic range expansion method according to an embodiment of the present invention includes a frame memory 50 for storing red, green, and blue video data from an input line, respectively; Dynamic range conversion / adjustment unit 60, inverse gamma correction unit 62, gain control unit 64, error diffusion unit 66, and subfield mapping unit 68 connected between the frame memory 50 and the panel 72. And a data alignment unit 70; An APL unit 74 and a waveform generator 76 connected between the inverse gamma correction unit 62 and the panel 72; A motion detector 56 and a motion degree determiner 58 connected in parallel with the frame memory 50 between the input line and the dynamic range converter / adjuster 60; Minimum and upper gray level detectors 52 and minimum distributions connected in parallel with the frame memory 50, the motion detector 56, and the motion degree determiner 58 between the input line and the dynamic range converter / adjuster 60. A lower gray level determination section 54 is provided.

The frame memory 50 stores red, green, and blue data from the input line in one frame unit and supplies the data to the motion detector 56 and the dynamic range converter / adjuster 60.

The motion detector 56 compares data of one frame unit inputted from a current input line with data of one frame unit delayed one frame from the frame memory 50. The current and delayed data are compared to detect motion at each gray level of data in one frame.

The motion degree determination unit 54 receives the degree of motion for each image from the motion detection unit 52 as input data and determines the degree of motion at each gray level between the frames. The determination information thereby is supplied to the dynamic range conversion / adjustment unit 60.

The minimum distribution lower and upper gray level detector 52 includes a histogram detector 82 of lower and upper gray levels and a minimum distribution lower and upper gray level value determiner 84 as shown in FIG. 13.

The histogram detector 82 of lower and upper gray levels detects histograms of lower and upper gray levels for each gray level based on data from an input line by one frame. This first obtains the overall distribution of each gray level for the input screen of one frame. The histogram H (I), which is a gray level distribution value of the input data, is detected based on the overall distribution. At this time, histograms are mainly detected at gray levels, such as about 0 to 20 gray and 220 to 255, to determine minimum and maximum gray levels (MIN and MAX).

The minimum distribution lower and upper gray level value determination unit 84 determines an arbitrarily set reference ratio and determines lower and upper gray levels MIN and MAX having less gray level distribution through histograms of the detected lower and upper gray levels. The lower and upper gray levels (MIN, MAX) with less determined gray level distribution are supplied to the dynamic range conversion / adjustment unit 60.

The minimum distribution lower gray level determination unit 54 sets the minimum gray level that is expressive even through error diffusion, and the minimum distribution lower gray level determined by the minimum distribution lower and upper gray level value determination unit 84 and the predetermined minimum gray level. Information about the magnitude relationship between levels is supplied to the dynamic range conversion / adjustment unit 60.

The dynamic range converting / adjusting unit 60 serves to maintain and enlarge the dynamic range of the input data via the frame memory 50 in accordance with the degree of movement and the expressive power below the minimum gray level. The dynamic range converting / adjusting unit 60 first determines whether the dynamic range is enlarged based on whether or not the movement degree is determined from the movement degree determining unit 56. For example, if the motion degree is determined to be a moving image by determining the degree of motion, the input data expands the dynamic range using the minimum distribution lower and upper gray level values MIN and MAX. In addition, the dynamic range converting / adjusting unit 60 determines whether or not the dynamic range is expanded based on the magnitude information derived from the minimum distribution lower gray level determination unit 54. The minimum distribution lower gray level determination unit 54 sets a minimum gray level with expressive power even through error diffusion. For example, when the minimum gray level is 5, the input data is expanded when the minimum gray level determined by the minimum distribution lower and upper gray level value determination unit 84 is 5 or less. If the minimum distribution lower gray level is 5 or more while input to the inverse gamma correction unit 62, the gray levels are 0, 5, 5.8, 6.6,... As shown in FIG. , 23, 24, 25,... The dynamic range is converted to the inverse gamma correction unit 62 by using the same or the like.

The inverse gamma correction unit 62 includes a gamma correction unit 86 and a gamma correction value adjusting unit 88 selectively connected to the gamma correction unit 86 as shown in FIG. The gamma correction unit 86 performs inverse gamma correction on the video signal input from the dynamic range conversion / adjustment unit 60 to linearly convert the luminance value according to the gray value of the video signal. The converted luminance value is supplied to the gain control unit 64 as shown in Fig. 14C. The gamma correction value adjusting unit 88 receives the luminance values linearly converted from the gamma correction unit 86 and takes the intermediate values of these luminance values and supplies them to the gain control unit 64 to increase the expressive power. Its median value can be represented by Equation 2.

Here, A (I) represents a luminance value linearly converted from the gamma correction unit 86, and B (I) represents an intermediate value of the luminance values linearly converted through gamma correction. For example, when the luminance values due to gamma correction at gray levels 5 and 5.818 are 0.0203 and 0.0293, the converted linear luminance values for gray level 5.818 are 0.0248.

The APL unit 74 receives the video data corrected by the inverse gamma correction unit 62 and generates an N-stage signal for adjusting the number of sustain pulses. The gain control unit 64 amplifies the video signal corrected by the inverse gamma correction unit 62 by the effective gain.

The error diffusion unit 66 finely adjusts the luminance value by diffusing an error component of a cell into adjacent cells. The subfield mapping unit 68 reallocates the video data corrected by the error diffusion unit 66 for each subfield.

The data aligner 70 aligns the video signal to be supplied to the panel 72, and supplies the video signal to an address driving integrated circuit (IC) not shown.

The waveform generator 76 generates a timing control signal by the N-stage signal input from the APL unit 74, and converts the generated timing control signal into an address driving IC, a scan driving IC, and a sustain driving IC of the panel 72. Supply.

In detail, the APL unit 74 that receives the inverse gamma corrected video signal generates an N-stage signal for adjusting the number of sustain pulses and supplies it to the waveform generator 76. The waveform generator 76 generates a timing control signal using the N-stage signal input from the APL unit 74, and supplies the generated control signal to the address driving IC, the scan driving IC, and the sustain driving IC.

The gain control unit 64 receiving the inverse gamma corrected video signal amplifies the corrected video signal by the effective gain and supplies it to the error diffusion unit 66. The error diffusion unit 66 diffuses the video signal input from the gain control unit 64 to finely adjust the luminance value. The video signal output from the error diffusion unit 66 is input to the subfield mapping unit 68. The subfield mapping unit 68 reallocates the error-diffused video data for each subfield and supplies it to the data alignment unit 70. The data alignment unit 70 aligns the video signal and supplies it to the address driver IC.

Thereafter, an image corresponding to the video signal is displayed on the panel 72 by the control of the address driving IC, the scan driving IC and the sustain driving IC. In the driving apparatus of the PDP according to the embodiment of the present invention having such a configuration, when the dynamic range of the video signal having the gray levels except the gray level having no expressive power is enlarged, the image is uniform with respect to the full gray scale as shown in FIG. 17. In addition to displaying, the contrast can be improved to obtain a clear image.

As described above, the driving apparatus and method of the plasma display panel using the dynamic range expansion method according to the present invention are gray level without expression power to solve the problem that the expression cannot be expressed at low gradation when the dynamic range of the moving image input image is enlarged. After excluding the followings, the dynamic range can be enlarged, and then the data can be controlled to improve contrast and display clear video. In addition, it is possible to improve the display capability of a moving image by converting a video signal having a gray level except gamma level having less expressive power to a median value after gamma correction.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1 is a block diagram illustrating an apparatus for driving a plasma display panel using a dynamic range expansion method according to the related art.

FIG. 2 is a block diagram illustrating in detail the PDP driver shown in FIG. 1.

FIG. 3 is a flow chart for explaining the dynamic range expansion method described with reference to FIG. 1.

4 is a diagram showing a histogram distribution change with respect to a gray level according to the prior art.

5A and 5B illustrate changes in the display image before and after applying the dynamic range expansion method.

FIG. 6 is a diagram for comparing only a part of the display image illustrated in FIG. 5B.

7A and 7B illustrate changes in histogram distribution after dynamic range expansion according to the prior art.

8A and 8B illustrate changes in a display image of a portion of FIG. 6.

9A and 9B are diagrams illustrating changes of a display image with respect to another part of FIG. 6.

10 is a diagram illustrating a representation state during gamma processing after dynamic range expansion according to the prior art.

FIG. 11 is a diagram illustrating gradation and luminance values for each gray level when driving a PDP according to a dynamic range expansion method according to the related art.

12 is a diagram illustrating a driving device of a PDP using a dynamic range expansion method according to an embodiment of the present invention.

FIG. 13 is a diagram illustrating in detail a minimum distribution lower and upper gray level detector of FIG. 12.

FIG. 14 is a diagram illustrating gray levels and gray scale values according to the driving apparatus shown in FIG. 12.

FIG. 15 is a detailed diagram illustrating an inverse gamma correction unit illustrated in FIG. 12.

FIG. 16 is a diagram illustrating a change in a gray value according to the gamma correction value adjusting unit shown in FIG. 15.

FIG. 17 is a diagram illustrating a representation state during gamma processing after dynamic range expansion processing of a PDP according to an embodiment of the present invention. FIG.

<Description of Symbols for Main Parts of Drawings>

12: input line 14,50: frame memory

16 dynamic range adjustment unit 18 PDP drive unit

22,82: gray level histogram detector

24,84: minimum distribution gray level determination unit

32,62: inverse gamma correction unit 34,64: gain control unit

36,66: error diffusion unit 38,68: subfield mapping unit

40,70: data alignment unit 44,74: APL unit

46,76: waveform generator 48,72: panel

52: minimum distribution upper / lower gray level detection unit 56: motion detection unit 58: movement degree determination unit 60: dynamic range conversion / adjustment unit 62: inverse gamma correction unit

delete

86: gamma correction unit 88: gamma correction value adjustment unit

Claims (17)

A frame memory for storing video data input from an external input line in units of frames, When the minimum distribution lower and upper gray levels are above a predetermined threshold by being connected in series to the frame memory, the minimum distribution lower and upper gray levels smaller than the threshold are removed, and the movement between the previous and current frames is greater than or equal to a predetermined threshold. A dynamic range adjusting unit for converting the dynamic range of the video data using the removed minimum distribution lower and upper gray levels; A plasma display panel driver connected in series to the dynamic range adjusting unit to control and supply a corrected image data signal having an enlarged dynamic range to a panel; A motion amount detecting unit connected in parallel with the frame memory between the input line and the dynamic range adjusting unit to detect a motion amount between a previous and current frame; A minimum distribution lower and upper gray level detection unit connected in parallel with the frame memory between the input line and the dynamic range adjusting unit to detect a minimum distribution lower and upper gray level during one frame; And a minimum distributed lower gray level determination unit configured to determine a magnitude relationship between the minimum distributed lower gray level detected in series and connected to the minimum and lower gray level detectors and the dynamic range adjuster in series. An apparatus for driving a plasma display panel using a range expansion method. The method of claim 1, The motion detection unit detects the movement degree at the same point by comparing the previous and current frame data, and determines the presence or absence of movement according to the movement degree; And a motion degree judging unit which receives a degree of motion for each image from the motion detection unit from input data and detects information on whether the degree of motion occurs on the entire screen between frames. An apparatus for driving a plasma display panel using an enlargement method. The method of claim 1, The minimum distribution lower and upper gray level detection unit detects each gray level of the video data during one frame input from the outside, and then the histogram detection unit of the lower and upper gray level detecting the histogram distribution ratio which is the distribution number of the lower and upper gray levels. Wow, And a minimum distribution lower and upper gray level determination unit connected in series to the lower and upper gray level histogram detectors to determine a minimum distribution lower gray level. The method of claim 1, The plasma display panel driver includes an inverse gamma correction unit that linearly converts a luminance value according to a gray value of an image signal by performing an inverse gamma correction on the video signal via the dynamic range adjusting unit; A gain controller for amplifying the video signal corrected by the inverse gamma correction unit by an effective gain; An error diffusion unit for finely adjusting the luminance value by diffusing an error component of the cell into adjacent cells; A subfield mapping unit for reallocating the video data corrected by the error diffusion unit for each subfield; And a data alignment unit for aligning the video signal to be supplied to the display panel. The method of claim 4, wherein The inverse gamma correction unit further comprises a gamma correction value adjusting unit which adjusts the linearly converted luminance value by taking an intermediate value of the linearly converted luminance values to increase the expressive power. Driving device of the plasma display panel. The method of claim 5, wherein An average image value (APL) unit receiving the video data corrected by the inverse gamma correction unit and generating an N-stage signal for adjusting the number of sustain pulses; And a waveform generator for generating a timing control signal based on the N-stage signal input from the average image value unit and supplying the generated timing control signal to a driving integrated circuit of the display panel. An apparatus for driving a plasma display panel using the same. Detecting the amount of motion by comparing previous and current frames with respect to the moving image input image; Detecting a minimum distribution lower and upper gray level of the moving image input image; Determining a magnitude and magnitude relationship between the detected motion amount and the detected minimum distribution lower and upper gray levels, respectively; When the detected minimum distribution lower and upper gray levels are greater than the threshold, the minimum distribution lower and upper gray levels smaller than the threshold are removed, and when the movement amount is greater than the threshold, the removed minimum distribution lower and upper gray levels are removed. And converting the dynamic range of the input image using the dynamic range expansion method. The method of claim 7, wherein Converting the dynamic range of the input image, Maintaining the dynamic range of the input image when the amount of motion and the detected minimum distribution lower and upper gray levels are smaller than a preset threshold; and driving the plasma display panel using the dynamic range expansion method. . The method of claim 8, The input image from which the gray level smaller than the threshold is removed is divided into predetermined intervals so that a predetermined region of the minimum distribution lower gray level fills the number of the removed gray levels. Driving method. The method of claim 8, And linearly converting a luminance value according to a gray value of the input image in which the dynamic range has been enlarged. The method of claim 10, Linearly converting luminance values according to grayscale values of the input image may include obtaining an intermediate value of the converted luminance values; And rearranging the luminance values according to the gray values of the input image in the array of the intermediate values. The method of claim 11, Amplifying the linearly converted video signal by an effective gain; Finely adjusting a luminance value by error diffusion of the amplified video signal; And reallocating the error-diffused video signal for each subfield to supply the panel to the panel. The method of claim 12, Generating an N-stage signal for adjusting the number of sustain pulses by receiving the linearly converted signal; And generating a timing control signal by using the input N-stage signal, and supplying the generated control signal to a driving circuit. The method of claim 7, wherein The detecting of the motion amount by comparing the previous and current frames with respect to the moving image input image may include detecting a histogram distribution ratio which is a distribution number of the detected gray levels; And determining a minimum distribution lower and an upper gray level using the histogram distribution ratio. The method of claim 14, The detecting of the histogram distribution ratio may include determining a histogram number of each gray level; And dividing the number of histograms by the resolution of the input image to express the percentage as a percentage. The method of claim 7, wherein The determining the minimum and lower gray level distributions may include setting a threshold for the histogram distribution ratio; And setting the first gray level coming out above the threshold to a minimum distribution lower and upper gray level. The method of claim 16, The step of enlarging the dynamic range of the input image may include determining a gray level of image data input from the outside; And determining the gray level of the image data corrected using the gray level, the minimum distribution lower and upper gray level of the input image data.