JP2008191605A - Plasma display panel driving method and plasma display apparatus - Google Patents

Abstract

The present invention relates to a PDP apparatus and the like, and provides a technology capable of suppressing image quality degradation that occurs when the first technology is used, particularly flickering at an edge portion of an image and vertical resolution degradation.
In a correction function 401 of the present PDP device, input display data is input by a luminance edge processing function 406 during simultaneous drive display with a predetermined luminance ratio of an image line pair and a pixel pair according to the first technique. Based on the characteristics of the edge portion of the luminance and the like, the part where the image quality deterioration becomes apparent in the image is identified, and the correction condition for correcting the display data including the target part is controlled and determined. Then, the pixel data correction processing function 411 corrects the display data according to the correction conditions so that the image quality deterioration is suppressed.
[Selection] Figure 1

Description

  The present invention relates to a plasma display panel (PDP) driving method and a multi-tone display method and apparatus such as a display device (plasma display device: PDP device), and more particularly to image processing for suppressing image quality deterioration.

  Display devices such as PDP devices are strongly required to realize higher-definition moving image display performance. In order to realize this, it is necessary to increase the number of pixels (cells) formed on the panel (PDP) and increase the display resolution. However, an increase in the number of pixels causes a decrease in luminance, an increase in device cost, an increase in power consumption, and the like. Therefore, in order to increase the resolution, it is an issue to realize an appropriate balance between image quality performance such as luminance and device performance such as cost and power consumption.

  In particular, in a PDP apparatus, the basic progressive display and interlace display methods require a relatively large amount of power for the address operation.

  As a prior art with respect to the said subject, the thing of Unexamined-Japanese-Patent No. 10-133621 (patent document 1) is mentioned, for example. This technique relates to compensating for a decrease in luminance accompanying an increase in the resolution of a panel and suppressing an increase in power consumption accompanying an increase in image data. Specifically, in this technique, in a panel capable of progressive display, interlaced display is performed according to the image type. In the original interlaced display, pixels (cells) on the display line to be driven are The same data as that of the adjacent display line to be driven is given to drive display. By using the interlaced display, the change in the address data is halved, so that the power consumption during the address operation is reduced, and the power consumption in the entire system is reduced. Further, the simultaneous lighting of two lines has an effect of ensuring the same luminance as that of progressive display.

  In addition, a technique for dealing with the above problem from the aspect of panel structure has been proposed. For example, the thing of Unexamined-Japanese-Patent No. 9-160525 (patent document 2) is mentioned. This relates to a common electrode type PDP (so-called ALIS-PDP) in which electrodes are shared between adjacent pixels. By combining this panel structure with so-called ALIS driving, high resolution is realized with a small number of electrodes (about half the number of pixels in the vertical direction), and both high resolution and low cost are achieved.

Japanese Patent Laid-Open No. 2003-233346 (Patent Document 3) describes a method necessary for applying the method disclosed in Patent Document 1 to the PDP disclosed in Patent Document 2.
JP-A-10-133621 JP-A-9-160525 JP 2003-233346 A

  As described above, interlaced display is possible in the display area of a panel capable of progressive display, as in the technique of Patent Document 1, as a measure against luminance reduction, cost increase, and power consumption increase associated with higher panel resolution. In this case, a method of simultaneously driving and displaying adjacent display lines with display data of the same display line (referred to as the first technique (two-line driving) for the sake of explanation) is effective. In other words, in the first technique, in the mode in which odd or even lines are displayed in the odd or even field, the second technology is adjacent to the pixels (cells) of the first line to be displayed in the vertical direction. The pixels (cells) in this line are simultaneously driven and displayed with the same luminance or the luminance attenuated at a constant ratio. A pair (set) of two adjacent display lines is a control unit. The display panel structure to which the first technique can be applied is not particularly limited. By the first technique, the address operation is simply halved to obtain an effect such as low power consumption.

  However, when the first technique is used, image quality deterioration, in particular, (1) occurrence of flickering or fluctuation of the image due to luminance change at the boundary (edge) portion of the image, (2) enlargement of the pixel display in the vertical direction, In other words, there is a problem that a reduction in resolution (resolution) in the vertical direction occurs due to equivalent display in a line pair (pixel pair). In the above-described prior art example, a method for dealing with such image quality deterioration is not described.

  The present invention has been made in view of the above problems, and an object thereof is related to a PDP apparatus that performs multi-gradation display processing, and suppresses image quality degradation that occurs when the first technique is used. It is to provide a technique capable of realizing prevention, particularly, (1) suppression of flickering and fluctuation at the boundary portion of an image, and (2) suppression of deterioration in resolution in the vertical direction of the image.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows. In order to achieve the above object, the present invention is a technique of a PDP driving method and a PDP device for performing multi-grayscale display processing, and includes the following means and configuration.

  This PDP device first drives and displays a PDP using the first technique in a configuration capable of basic interlaced display (display of odd or even lines in a display area) for a PDP having a structure capable of progressive display. First means (two-line driving means) are included. That is, when driven by the first means, the target line pair and the pixel pair on the target line pair are adjacent to the pixel (P1) on the first line (eg, odd line) in the vertical direction. The pixel (P2) on the second line (e.g., even line) to be processed has the same luminance or a predetermined luminance ratio (first condition) as the pixel (P1) of the first line based on the display data of the first line. ) And drive display (address operation and sustain operation) at the same time with the brightness attenuated in step (3).

  In this PDP apparatus, when the line pair and the pixel pair are driven by the first means, the feature of the luminance edge portion (the amount of luminance change) extracted from the display data of the image to be displayed in order to suppress image quality degradation. And orientation), screen polarity (odd or even field), brightness of the two pixels (P1, P2) of the pixel pair, brightness ratio of the pixel pair (first condition), etc. The conditions are determined and correction processing is performed.

  (1) In this PDP driving method, in order to cope with the problem (1) (flickering of the edge portion, etc.), when driving by the first means, the target line pair and pixel pair are determined based on the first condition. Correction conditions for correction processing for correcting display data are determined, and correction processing for correcting display data of a target line pair and pixel pair is performed based on the correction conditions. In the correction processing, the light emission gravity center position between the two pixels (P1, P2) of the pixel pair corresponding to the luminance ratio of the first condition is set so that the luminance change between the two pixels of the pixel pair becomes gentle. Correction is made so that the luminance and the total luminance at the time of individual simultaneous light emission of the two pixels of the pixel pair substantially coincide.

  In the display mode of the first means, the PDP device is configured to display each pixel (P1, P2) adjacent in the vertical direction in the target line pair and pixel pair in at least one line pair display in the image. There is a second means for correcting the original display data according to the first condition. In the second means, when displaying an image including a line pair by the first means, a process for determining the luminance ratio of the first condition, and based on the first condition, the target line pair by the first means and A process for controlling and determining a correction condition for a correction process for correcting display data of the pixel pair, and a correction process for correcting display data of the target line pair and pixel pair based on the correction condition.

  Further, for example, the correction process is a weighted average process (filter process) of original display data of each pixel (P1, P2) constituting the pixel pair. Further, for example, the correction processing may be performed by converting a data value at an arbitrary position between two pixels (P1, P2) of a pixel pair according to the luminance ratio of the first condition into a linear function of coordinates between the two pixels. This is a process of calculating as a point to be interpolated based on the above. Also, for example, in the second means, the correction condition (third condition) is referred to by referring to a positional relationship between a specific part where a predetermined luminance change occurs between the pixels of the pixel pair in the image and the pixel pair, and the correction condition (third condition). Determine whether processing is valid or invalid.

  (2) In this PDP driving method, in order to cope with the problem (2) (deterioration in the resolution in the vertical direction), the pixels of the image to be displayed based on the input display data when driven by the first means The brightness condition for each pixel is acquired, the edge portion where the predetermined brightness change occurs and the feature thereof are extracted based on the brightness data, and the correction condition for correcting the display data of the pixel of the image based on the feature of the edge portion is set. The correction processing is performed to correct the display data of the pixel of the image based on the correction condition. In the correction process, correction corresponding to the feature of the edge portion is performed on the display data of the pixel of the edge portion in the display target image so as to suppress the deterioration of the resolution in the second direction of the image.

  This PDP device is a pixel in a portion (edge portion) where a luminance difference occurs in display data of an image to be displayed in at least one line pair display in the image in the display mode by the first means. In addition, the processing of extracting the feature of the edge portion (analyzing the luminance change state between the pixels) and the display data of the pixel of the part according to the feature (the luminance difference state), Control and determine the correction conditions for correction processing to improve the vertical resolution of the image by calculation or selection from a plurality of correction conditions, and display data of the image pixels based on the correction conditions And a third means for performing correction processing.

  Further, for example, the correction process is a weighted average process (filter process) of original display data of each pixel (P1, P2) constituting the pixel pair. For example, the third means refers to the direction of the luminance change at the position of each pixel to be corrected and the information on the polarity of the odd or even screen in the display of the display target image, and sets the correction condition. Decide to optimize.

  In another PDP apparatus, the third means refers to the movement of each pixel to be corrected, and selects and applies a suitable correction process based on the movement. For example, the weighted average process or the like is selected for a part where the amount of motion is not 0, and an arithmetic process is selected as a correction process for a part where the amount of motion is 0. In this calculation process, a correction amount (Δ) is provided for the added image of the odd and even screens reflecting the luminance ratio of the first condition, and the added image taking the correction amount into account and the luminance change of the edge portion are calculated. A process of calculating the correction amount is performed so that the gradual target image with little deterioration in image quality substantially matches.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows. According to the present invention, the present invention relates to a PDP device that performs multi-gradation display processing and the like, and particularly suppresses and prevents image quality degradation that occurs when the first technique is used. And (2) suppression of deterioration of resolution in the vertical direction of the image.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted. The subfield is abbreviated as SF.

<Conventional technology>
First, in order to explain the embodiment of the present invention in an easy-to-understand manner with reference to FIG. 17 to FIG. 19, a prior art example (premise technique) and problems with respect to the embodiment of the present invention will be briefly described. Deterioration in image quality that occurs when the first technique (two-line driving) is used, in particular, (1) occurrence of image flickering or fluctuation due to luminance change at the boundary of the image, and (2) vertical direction of pixel display The situation about the reduction in resolution due to enlargement to will be described. Note that driving display (driving or displaying) for a line, a pixel, or the like in a PDP device refers to performing lighting (ON) / non-lighting (OFF) of a cell by an address operation and a sustain operation.

<(1) Flicker at the edge>
17 and 18, first, (1) the situation of occurrence of flickering at the boundary portion of the image will be described. Here, for the purpose of explanation, in the original interlaced display (method of driving and displaying in the field in which the odd and even lines in the panel display area are time-divided), pixels on the line to be driven in a certain field are A pixel on the line which is called a main pixel (P1) and is not driven in the field but is controlled to be driven simultaneously with the main pixel (P1) by the processing of the first technique is referred to as an auxiliary pixel (P2). ).

  FIG. 17 shows an original interlace display. As shown in (a), a still image 101 in which a black rectangle exists in a white background is taken as an example. Let the horizontal (horizontal) direction and the vertical (vertical) direction of the display screen be x and y on the coordinate axes. Here, (b) shows the intensity distribution profile of each pixel along the line segment AB in the y-axis direction in the case of a progressive screen (Fp) in which odd / even lines are combined. The horizontal axis represents each pixel, and the vertical axis represents the emission intensity (E) of each pixel. In the case of interlaced display, the image frame is divided into an odd screen (odd field Fo) composed only of odd lines (Lo) and an even screen (even field Fe) composed only of even lines (Le). indicate. A white circle indicates a pixel (odd pixel) on the odd line (Lo), and is an object to be driven when the odd screen (Fo) is displayed. A black circle indicates a pixel (even pixel) on the even line (Le), and is a driving target when the even screen (Fe) is displayed. The emission intensity has only two levels (K1, K2) corresponding to the black rectangular portion and the white background portion of the still image 101.

  Further, (c) and (d) show the intensity distribution profile of each pixel along the line segment AB on each odd / even screen (Fo, Fe). By repeatedly displaying an odd screen (Fo) and an even screen (Fe) having this profile, for example, at a frequency of 60 Hz, each pixel along the line segment AB appears to have the profile (b). It is perceived by the user like an image of In this way, in interlaced display, blinking is repeated for all pixels, but if the repetition period is sufficiently short, the edge portion of the image (for example, the boundary line between the black rectangular portion and the white background portion) fluctuates, There is no flickering phenomenon.

  In FIG. 18, the display according to the first technique is shown in the same manner as in FIG. The case where the still image 101 of FIG. (A) is an intensity distribution profile of pixels along the line segment AB in the progressive screen (Fp). (B) and (d) show the profiles of the conventional odd-numbered screen (Fo) and even-numbered screen (Fe) of interlaced display, respectively. In each profile, a pair of two pixels (PP) surrounded by an ellipse indicates a pair of a main pixel (P1) and an auxiliary pixel (P2) that is driven at the same time. In the pixel pair (PP), the pixels on the odd line (Lo) in the odd screen (Fe) and the pixels on the even line (Le) in the even screen (Fe) are the main pixels (P1), respectively. The opposite side is the auxiliary pixel (P2). For the sake of explanation, the pixel pair (PP) is shown only for a part, but in the same manner, the pixel pair (PP) becomes two pixels at a time.

  Therefore, as in (c) and (e), the intensity distribution profile in the case where both the pixels (P1, P2) of the pixel pair (PP) are simultaneously driven and displayed with the same luminance is formed by the first technique ( Fo2, Fe2). As in the case of the normal interlaced display, the two states (c) and (e) are repeatedly displayed at a frequency of 60 Hz, for example. Here, when the light emission states of the odd-numbered screen ((b) Fo, (c) Fo2) and the even-numbered screen ((d) Fe, (e) Fe2) are compared, the number of light-emitting pixels is equal to that of the conventional interface. It can be seen that in the case of the first technology, the luminance is doubled and the brightness of the entire screen is increased with respect to the lace display. However, in the case of the first technique, for example, in two pixels indicated as pA and pB, by repeating the two states (c) and (e), the luminance greatly changes in the repetition cycle. (204, 205). On the other hand, in pixels other than the two pixels (pA, pB), there is no change in luminance even if the two states (c) and (e) are repeated. In this way, when a change in emission intensity occurs in a specific part, that is, at an edge portion of luminance, etc., the part flickers or the boundary position in the image moves and appears to fluctuate. Perceived as This phenomenon is one of the problems to be solved.

<(2) Reduction in resolution in the vertical direction>
Next, referring to FIG. 19, (2) a state in which the resolution in the vertical direction is lowered will be described. Here, the boundary part of the diagonal line in the pixel area where the still image is displayed is taken as an example. (A), (b), and (c) compare the luminance distribution state of the oblique line boundary between the normal interlaced display and the case of the first technique. In this example, the pixel area of 25 pixels in 5 rows and 5 columns is shown enlarged. Further, the luminance for each pixel is shown without considering the sub-pixels (cells) of the three colors R, G, and B constituting the pixel. White pixels indicate low luminance (luminance level 1 (k1)), and hatched pixels indicate high luminance (luminance level 2 (k2)).

  (A) has shown the case where an original image is displayed progressively. The same image is displayed on the odd-numbered screen (Fo) 301 and the even-numbered screen (Fe) 302, and a high-brightness image with a resolution maintained is obtained as a composite image (G1) 303 thereof. Here, the pixels with vertical lines are twice as bright (brightness level 3 (k3)) as the luminance (k2) of the hatched pixels.

  (B) is a case of interlaced display. The odd-numbered screen (Fo) 304 and the even-numbered screen (Fe) 305 are each displayed with an odd / even line jump. Therefore, the luminance (k2) of these synthesized images (G2) 306 is half of the luminance (k3) of the progressive image (G1) 303 of (a), but the resolution is maintained.

  (C) has shown the case of the display by the 1st conventional. As described above (FIG. 18), the pixel pair (PP) including the main pixel (P1) and the auxiliary pixel (P2) in interlaced display and the corresponding line pair are simultaneously displayed based on the data of the main pixel (P1). Is done. Here, as a condition at that time (first condition: j1), it is assumed that two pixels (P1, P2) constituting the pixel pair (PP) emit light with the same luminance (luminance ratio is 1: 1). ). As a result, the brightness of the composite image (G3) 309 is doubled (k3) for pixels that emit light on both the odd screen (Fo) 307 and the even screen (Fe) 308, and for pixels that emit light only on one side. It becomes 1 time (k2), and the effect that the brightness of the entire image is improved is obtained. However, since the main pixel (P1) arranged in the vertical direction and the auxiliary pixel (P2) emit light with the same luminance, the spatial resolution is halved in the vertical direction and image quality deterioration occurs. This phenomenon is one of the problems to be solved.

<First technology (2-line drive)>
In FIG. 20, the outline of the interlaced display and the first technique (two-line drive), which are the prerequisite technologies, and the usage relationship of the display data are schematically shown and will be described briefly. In (a), in a normal interlaced display system, display lines of some areas in two odd and even fields Fo and Fe (for example, F1 and F2) for forming one image frame (f). (Example: L1-L4) and display data (Example: DL1-DL4) used for driving the same are shown. The white part is a driving target. In F1 (Fo), an odd line (example: L1) is driven by the display data (example: DL1), and in F2 (Fe), an even line (example: L2) is driven by the display data (example: DL2). To do. In the same field, the lines to be driven are sequentially scanned and driven. As a control unit, adjacent odd-numbered and even-numbered display line pairs are indicated as LP (for example, LP1, LP2).

  In (b), 2-line drive control based on the interlaced display control in (a) is similarly shown. The arrows indicate the usage relationship of the same display data. In this control, in the interlaced display of (a), the pixels (cells) on the non-driving target line are simultaneously driven and displayed based on the same display data as the driving target line. In this control, one line of data is simultaneously written to two lines during the SF address period. That is, the scanning timing of the line pair during the address operation is the same. In this control, in each line pair (LP) of the display area of the PDP 10, in F1 (Fo), an odd line (for example, L1) and its pixel (P1) are compared with an even line (L2) and its pixel (P2). The display is driven using the display data (DL1) of the odd line (L1). In the pixel pair (PP) unit, the auxiliary pixel P2 is driven so as to have the same luminance or the luminance attenuated at a predetermined luminance ratio (α) with respect to the main pixel P1. In the subsequent F2 (Fe), the driving object and display data are used in the same manner with the usage relationship of F1 (Fo) reversed. In the same field, the line pairs to be driven (for example, LP1 and LP2) are sequentially scanned and driven. By this control, effects such as compensating for a decrease in luminance accompanying an increase in the resolution of the panel and suppressing an increase in power consumption accompanying an increase in image data are obtained.

(Embodiment 1)
Based on the above, the PDP apparatus according to the first embodiment of the present invention will be described with reference to FIGS. As a feature, the first embodiment is provided with a correction function 401 which is a processing function for dealing with both the problems (1) and (2). The correction function 401 is roughly composed of a function for determining a correction condition based on a luminance edge portion of an image (luminance edge processing function 406), a function for correcting display data based on the correction condition (pixel data correction processing function 411), and the like. It is composed of In addition, the form etc. which comprise the processing function for addressing the problem of said (1) or (2) separately are also possible. In the present embodiment, the display mode by the two-line drive can be selectively executed with respect to the basic interlaced display mode. In the present embodiment, the two-line driving means is realized as a processing function in the drive control circuit (particularly, the image data processing unit 1300) of the PDP 10 as in the conventional case. Further, in the case of two-line driving, the usage relationship of the same display data is in line units, and all pixel pairs of the line pair to be driven are processed based on the same first condition (j1). In addition, the driving target in the case of the two-line driving is assumed to be all line pairs in the display area of the PDP 10.

<Correction function>
FIG. 1 shows a configuration example (software processing flow) of a correction function (correction process) 401 in the PDP apparatus according to the first embodiment. In FIG. 1, the flow of data / information, correction processing steps, and the like will be described. The correction function 401 is realized by the processing of the correction processing unit 100 in FIG.

  Before and after the correction function 401, there are known processes 402 and 403 necessary for PDP drive display control, but a description thereof will be omitted. The input image data (display data: d1) 404 has R, G, and B data for each pixel of the image (frame). The image data (d1) 404 input to the correction function 401 is separated into two processing functions and processed in parallel. One of them is a luminance edge processing function 406, and the other is a pixel data correction processing function 411. Further, the first condition (j1) 405 in the two-line driving is input to the correction function 401. The first condition (j1) 405 is information on the luminance ratio (α) that is a simultaneous lighting condition of the line pair and the pixel pair (PP) in the two-line drive. The first condition (j1) 405 is, for example, set in advance in the PDP apparatus or set for user input.

  The luminance edge processing function 406 includes processing steps of luminance conversion processing 407, luminance edge portion extraction processing 408, luminance edge feature extraction processing 409, and correction condition control processing 410. In the luminance conversion processing 407, luminance data (d2) of the pixel is calculated from R, G, B data (d1) for each input pixel. In the luminance edge portion extraction processing 408, processing for calculating a luminance change point, that is, a luminance edge portion, is performed from the luminance data (d2) converted by the luminance conversion processing 407. In the luminance edge feature extraction process 409, a process of extracting features such as intensity, orientation, rank in the same screen, coordinates, and the like is performed on the luminance edge part extracted by the luminance edge part extraction process 408.

  In the correction condition control process 410, the edge pixel correction process (413) condition (413) is determined based on the brightness edge feature extracted by the brightness edge feature extraction process 409 and the first condition (j 1) input separately. The second condition: j2) is controlled. In the correction condition control process 410, the condition (third condition: j3) of the image-to-data correction process (412) is controlled based on the feature of the luminance edge.

  On the other hand, the pixel data correction processing function 411 includes processing steps of pixel pair data correction processing 412 and edge portion pixel correction processing 413. In the pixel data correction processing function 411, each R, G, B data (d2) of each pixel is individually processed in parallel. In the pixel pair data correction processing 412 step, the third condition (j3) for the correction processing based on the feature of the luminance edge and the first condition (j1) input separately are referred to, and based on this, the pixel pair is determined. The display data of each pixel (P1, P2) constituting the image is corrected.

  In the edge part pixel correction process 413, the pixel data after the correction process by the pixel pair data correction process 412 is corrected according to the correction condition (j2) determined by the correction condition control process 410. The corrected image data is output as display data (d3) for PDP drive display.

<PDP device>
In FIG. 2, the structural example of the PDP apparatus provided with the correction | amendment function 401 is shown. This PDP apparatus has a configuration in which a correction processing unit 100 is added to a conventional general PDP apparatus. In the configuration in which the correction processing unit 100 is arranged in the input stage of the conventional configuration, the display data and the like are corrected (correction processing), and the rest is the same as the conventional configuration, and the PDP 10 control is realized.

  In this PDP apparatus, input image data (d1) 1301 is processed by an image data processing unit 1300, and control is applied to the PDP 10 based on data (d3) as a result of the processing. As an input signal of the PDP device, in addition to the image data 1301, a control clock, a vertical synchronization signal, a horizontal synchronization signal, and the like are provided as in the conventional case. The control / drive circuit unit includes an image data processing unit 1300, a Y sustain pulse control unit 1306, an X sustain pulse control unit 1310, an X sustain circuit 1311, a Y sustain circuit 1307, a scan driver 1308, an address driver 1309, and the like.

  The image data processing unit 1300 includes a scan controller unit 1302, a data controller unit 1303, an image processing processor unit 1304, and a frame memory unit 1305. The scan controller unit 1302 controls a line selection signal for address operation. The data controller unit 1303 expands the image data 1301 into fields and SF data (SF conversion processing) for gradation control. An image processor 1304 performs processing for improving image quality. The frame memory unit 1305 stores fields, SF data, and the like.

  The data processed by the image data processing unit 1300 is supplied to the X sustain pulse control unit 1310 and the Y sustain pulse control unit 1306, and the sustain discharge (sustain operation) is controlled by the Y sustain circuit 1307 and the X sustain circuit 1311. . The address operation is performed by controlling the address driver 1309 and the scan driver 1308 in synchronization.

  The PDP 10 is a three-electrode / AC drive (AC) type panel including, for example, an X electrode 31, a Y electrode 32, and an address (A) electrode 33, in which a display area is formed by a matrix of cells associated with pixels. Each driver (1311, 1307, 1308, 1309) drives the electrode group (31, 32, 33) of the corresponding PDP 10 by voltage application.

<PDP>
In FIG. 3, a structural example of the PDP 10 is shown by a portion corresponding to a set of three cells (Cr, Cb, Cb) associated with one pixel. The PDP 10 is configured by combining the structures of the front substrate 21 and the back substrate 22 so as to face each other, sealing the periphery thereof, and sealing the discharge gas in the space.

  On the front substrate 21 side, a panel plane extends parallel to the horizontal direction (first direction) and alternately from the Y electrode (scanning electrode) 32 and the X electrode (common electrode) 31 in the vertical direction (second direction). A group of display electrodes (sustain discharge electrodes) configured is arranged. These display electrode groups are covered with a dielectric layer 23 and a protective layer 24.

  On the back substrate 22 side, an address electrode 33 group is formed extending in parallel with the second direction, and further covered with a dielectric layer 26. Striped partition walls (ribs) 27 extending in the second direction are formed on both sides of the address electrode 33 on the dielectric layer 26. Further, between the partition walls 27, a phosphor 28 is applied that generates visible light of each color of red (R), green (G), and blue (B) when excited by ultraviolet rays.

  A display row (line) is configured corresponding to the pair of display electrodes (31, 32), and a display column and cell are configured corresponding to the intersection with the address electrode 33. A display area of the PDP 10 is configured by the cell matrix, and is associated with a field and SF that are display units. The PDP has various structures depending on the driving method.

<Field>
FIG. 4 shows a basic sequence configuration when displaying an image on the screen using the PDP 10. A unit for displaying one screen corresponding to the panel display area is referred to as a field (F). One field has a time of about 16 ms, for example. A video such as a moving image is obtained by changing a field-unit image in time series. The field is further divided into a plurality of subfields (SF) for gradation expression. For example, the field is composed of six SFs (SF1 to SF6). By displaying an image having a different luminance for each SF, a gradation is generated in the luminance of the image obtained in units of fields. Each SF is divided into a reset period 71, an address period 72, and a sustain (sustain discharge) period 73. In the reset period 71, initialization (reset) for the address operation performed in the subsequent address period 72 is performed. In the address period 72, an address operation for selecting a pixel (cell) to be discharged in the subsequent sustain period 73 is performed based on the display data. Specifically, an address discharge is generated in the target cell by applying a scan pulse to the Y electrode 32 and applying an address pulse to the address electrode 33. In the sustain period 73, the sustain pulse is applied to the X electrode 31 and the Y electrode 32 to generate light emission by the sustain discharge in the pixel (cell) selected in the address period 72.

  In the case of interlaced display, one image frame (f) is divided into two fields that are time-divided into an odd line (Lo) group and an even line (Le) group in the display area, that is, an odd field (Fo) and an even field ( Fe), and is displayed.

<Correction processor>
Next, FIG. 5 shows an internal configuration of the correction processing unit 100. This shows a hardware configuration example corresponding to the software configuration of FIG. The correction processing unit 100 includes a memory unit 1314, a luminance calculation unit 1315, a luminance edge calculation unit 1316, an edge determination processing unit 1317, a correction processing condition table 1318, a pixel pair data processing unit 1319, and an edge unit pixel processing unit 1320.

  The input image data (d1) 1301 is temporarily stored in the memory unit 1314. The memory unit 1314 is configured to store data of a plurality of lines in units of one line of the image data 1301. In this processing unit, data is simultaneously read from the plurality of lines and input to the luminance calculation unit 1315 and the pixel pair data processing unit 1320, respectively.

  In the luminance calculation unit 1315, calculation corresponding to the luminance conversion processing 407 is performed, and pixel luminance data (d2) is output. Next, the luminance edge calculation unit 1316 performs an operation corresponding to the luminance edge portion extraction processing 408 based on the luminance data (d2). Next, the edge determination processing unit 1317 performs a calculation corresponding to the luminance edge feature extraction processing 409. Then, the correction condition control process (410) is performed using the extracted information / data of the luminance edge feature. With respect to this processing, in the configuration example shown in FIG. 5, a plurality of correction conditions (correction conditions # 1 to #N) are stored in the correction processing condition table 1318, and are output from the correction conditions by the output (edge feature) of the edge determination unit 1317. The selected correction condition is output to the edge pixel processing unit 1320 and the like. The result of the edge determination processing unit 1317 is also reflected on the pixel pair data processing unit 1319. The correction condition control process (410) is not limited to the form of selecting from a plurality of correction conditions as described above, but may be a form of calculating and determining and outputting the correction conditions, for example. Further, the display data correction processing parts (1319, 1320) may be selected from a plurality of processing units in accordance with the correction conditions.

<Luminance edge processing (1), (2)>
Next, the processing steps by the luminance edge processing function 406 will be described with reference to FIG. As an example, the boundary portion of the diagonal line displayed as a still image (FIG. 19) is taken as an example. The series of (a), (b), (d), and (f) shows basic first luminance edge processing, and determines the second condition (j2) used for the edge pixel correction processing 413. Is. On the other hand, the series of (a), (c), (e), and (g) shows the second luminance edge process in addition to the above basic process, and the third pair used for the pixel pair data correction process 412. The condition (j3) is determined. First, (a) shows a state where the input pixel data (d1) is converted into luminance data (d2) for each pixel by the luminance conversion processing (407).

  (B) shows a result of extracting a portion regarded as a luminance edge portion (E1) from the luminance data (d2) by the luminance edge portion extraction processing (408). The edge portion (E1) is indicated by pixels with a checkerboard pattern. The edge calculation method at this time uses, for example, a known method of calculation from a 3 × 3 pixel array, but the calculation method is not limited to this.

  On the other hand, (c) is a region where there is a luminance difference as shown in the pixel pair (PP) in the luminance data (d2) of (a) (Q1: luminance change occurrence pixel pair). The result of the extraction process is shown. In the pixel pair indicated by Q1, one pixel has a luminance level k1, and the other pixel has a luminance level k2. In this extraction process, when the luminance level difference between the pixels of the pixel pair is equal to or greater than a predetermined threshold, for example, the part (Q1) is extracted.

  (D) is a result of analyzing each edge strength and its direction as an edge feature (E2) in each of the edge portions (E1) extracted in (b) by the luminance edge feature extraction process (409). is there. As the edge feature (E2), the length of the arrow (vector) indicates the edge strength of each pixel, and the direction indicates the edge direction.

  On the other hand, (e) selects the part (Q1) where the luminance difference exists between the pixels of the pixel pair (PP) extracted in (c) above with reference to the edge feature (E2) in (d). The result (Q2). Here, as a result (Q2), a part (Q1) where a luminance difference exists in the pixel pair (PP) extracted in (c) above, and a part having a strong edge strength in the edge feature (E2), The one corresponding to is selected. In this example, since the two parts (Q1) where the luminance difference exists coincide with the part where the edge strength is strong, both the two parts (Q1) are selected as the result (Q2).

  (F) shows a state in which the correction condition (j2) for the edge pixel correction (413) is determined from the edge feature (E2) extracted in (d) by the correction condition control process (410). ing. In the present embodiment, the edge pixel correction (413) uses a two-dimensional filter process (weighted average process). A circle given to the pixel represents a filter processing coefficient (filter coefficient (E3)) as the correction condition (j2). The size of the circle of the filter coefficient (E3) indicates the size of the pixel area used for the filter processing and the strength of the filter (the narrower the higher the filter coefficient). The filter coefficient (E3), which is the correction condition (j2) for the determined edge pixel correction (413), is finally optimized in consideration of the screen polarity (Fo or Fe) ( Later). This optimization process is included in the correction condition control process 410.

  On the other hand, (g) shows the correction condition (412) for the pixel pair data correction (412) determined from the result (Q2) of the selection of the part (Q1) where the luminance difference exists in the pixel pair (PP) in (e). The third condition: j3) is indicated. In this example, a condition (OFF) is set so that the pixel pair data correction (412) is not performed in the selected part (Q3).

<Pixel pair data correction (1)>
Next, the processing contents and effects of the pixel pair data correction (412) will be described with reference to FIG. Here, as described above, an oblique line image 601 displayed as a still image is taken as an example, as shown in FIG. The hatched portion is the high luminance portion (K2), and the white portion is the low luminance portion (K1). Since the intensity distribution profile of each pixel along the line segment AB is a still image, the odd screen (Fo) and the even screen (Fe) are the same, and (b) for Fo and (e) for Fe. . The horizontal axis represents each pixel, and the vertical axis represents the emission intensity of each pixel. White circles indicate pixels on the odd lines (Lo) (odd pixels), and during interlaced display, they are driven as the main pixel (P1) during odd screen (Fo) display. A black circle indicates a pixel (odd pixel) on the even line (Le). When interlaced display is performed, it is driven as the main pixel (P1) during even screen (Fe) display. A point between the white circle and the black circle represents a correction value (interpolation data 603) (described later).

  (C) and (f) relate to Fo and Fe, in a state where the pixel pair data correction (412) according to the present embodiment is not applied, and two-line driving, that is, the main pixel (P1) and auxiliary in the pixel pair (PP). This is a profile (Fo2, Fe2) when the pixel (P2) is simultaneously driven with the same data and the same luminance. In this case, as described above, for example, in the parts indicated by the pixels pA and pB, flickering occurs due to a large luminance change between the pixels. On the other hand, (d) and (g) are profiles when two-line driving is executed with respect to Fo and Fe by applying the pixel pair data correction (412) according to the present embodiment. As described above (FIG. 6), the pixel pair data correction (412) may reflect the processing result of the luminance edge processing function 406 as the correction condition (j3), which will be described later.

  In the present embodiment, in the pixel pair data correction (412), as shown in (b) or (e), a linear function (interpolation interpolation function) connecting the two points between the pixels of each pixel pair (PP). ) 604 is assumed. By this linear function 604, the intensity at an arbitrary position between the pixels of each pixel pair (PP) can be interpolated. Coordinate information (position) for interpolation is given as the first condition (j1) for two-line driving by the ratio of the lighting intensity of the main pixel (P1) and auxiliary pixel (P2) (luminance ratio: α). It is done. In this example, in order to make the main pixel (P1) and the auxiliary pixel (P2) have the same luminance, the ratio (α) given as the first condition (j1) is 1: 1. Accordingly, the distance between the main pixel (P1) and the auxiliary pixel (P2) is 1: 1 on the linear function 604 between the main pixel (P1) and the auxiliary pixel (P2) of each pixel pair (PP). The correction value (603) is obtained by substituting the coordinates of the intermediate point, that is, the middle point. By making this calculation result the value of the main pixel (P1) of each pixel pair (PP), pixel pair data correction (412) is performed. That is, as a result, as shown in (d) and (g), a corrected profile (Fo3, Fe3) for Fo and Fe is obtained. Here, in the case of no correction ((c) and (f)), the pixel pair in which the luminance change has occurred due to switching between the odd screen (Fo) and the even screen (Fe), for example, the pA and pB portions ( 605) shows that the luminance change is suppressed by this correction process. That is, the occurrence of flickering is suppressed.

<Pixel pair data correction (2)>
In FIG. 8, the case where the value of the first condition (j1) is different will be described by taking an image 601 similar to that in FIG. 7A as an example. In this example, as shown in (a) Fo and (d) Fe, the luminance ratio (α) between the main pixel (P1) and the auxiliary pixel (P2) of the pixel pair (PP) in the first condition (j1) is 1. : 0.6. In addition, the light emission gravity center position between two pixels (P1, P2) of the pixel pair (PP) corresponding to the luminance ratio (α) is indicated by c. Under this condition, the intensity distribution profile when the two-line drive is executed without applying the pixel-to-pixel correction (412) is as shown in (b) Fo2, (e) Fe2. In this case, as in the case where the luminance ratio (α) is 1: 1, for example, flickering or the like occurs due to the luminance change of the portion indicated by the pixels pA and pB.

  On the other hand, the case where this pixel pair data correction (412) is applied to (c) Fo3 and (f) Fe3 is shown. Since the luminance ratio (α) is 1: 0.6, the position of the interpolation data 803 in the pixel pair (PP) is biased toward the main pixel (P1) on the linear function 804, and (a) , (D), the point shown between the white circle and the black circle corresponds to the correction value. The results of correcting the data of the main pixel (P1) of the pixel pair (PP) (pixel pair data correction (412)) by the correction value data (803) are (c) and (f). As a result, for example, the luminance change of the part (805) indicated by pA and pB is reduced, so that the occurrence of flickering is suppressed.

  In other words, in the processing for suppressing the flickering of the edge portion, the luminance edge processing function 406 first performs the first operation when simultaneously driving the pixel pair on the target line pair during the two-line driving. One condition (j1) is judged (in this example, a set value is input). The luminance edge processing function 406 determines a display data correction condition (j2 and the like) of each pixel (P1, P2) of the pixel pair to be driven simultaneously according to the first condition (j1) of the determination result. Α is used as the coefficient of the luminance ratio which is the first condition (j1), and changes from α = 0 (0%) to 1 (100%: the same luminance). In this process, a virtual position (in other words, a pixel pitch α: 1 of the light emission gravity center position (c) of the two pixels (P1, P2) of the pixel pair to be driven simultaneously is greater than that at the time of single lighting. Then, it is considered that the main image (P1) moves in the direction of the auxiliary pixel (P2) to the position α / h). Therefore, in this process (edge part pixel correction process 413), as the display data correction condition (j2) for the pixel pair, the emission luminance at the moved position (correction value) and the two pixels (P1, P2) of the pixel pair are used. The display data of the pixel pair is corrected so as to satisfy the condition that the total luminance at the time of individual simultaneous light emission of () substantially matches.

<Pixel pair data correction (3)>
FIG. 9 shows an example in which the processing result of the luminance edge processing function 406 is reflected as the correction condition (third condition: j3) for the pixel-to-pixel correction (412) (FIG. 6C). , (E), (g)). In this example, the given correction condition (j3) is that when there is a luminance change between the pixels of the pixel pair (PP) and the edge intensity at that part is strong, the pixel pair data correction (412) is changed to an odd screen ( It shall be invalidated only in Fo).

  (A) Fo3, (c) Fe3 are the results after correction similar to those described above (FIGS. 7D and 7G). Here, for example, the pixel pair (PP) indicated by the pixels pA and pB has a luminance difference between the pixels and corresponds to the strongest edge position. Therefore, this corresponds to the condition (j3) in which the pixel pair data correction (412) is disabled only for the odd-numbered screen (Fo). Therefore, in this process, (a) the state of Fo3 is replaced with only the pixel pair (PP) of the pixels pA and pB to a state without correction. As a result, the entire profile is as shown in (b) Fo4.

  When this condition (j3) is not given, the pixels pA and pB are displayed on the odd screen (Fo) and the even screen (Fe) as shown in (a) and (c) by the pixel-to-data correction (412). An intermediate color is displayed. As a result, the luminance change is eliminated and flickering is suppressed. However, since the intermediate color region is clearly displayed, it may be recognized as image blur or outline. This is particularly noticeable when displaying thin lines or characters.

  On the other hand, when this condition (j3) is given, the screen for displaying the intermediate color is limited to the even screen (Fo) as shown in (c), and the luminance of the intermediate color is lowered. In addition, since the luminance difference between the pixels pA and pB is suppressed between the odd-numbered screen (Fo) and the even-numbered screen (Fe), a reduction effect such as flicker that is the purpose of the pixel-to-data correction (412) is also obtained. As a result, it is possible to achieve both suppression of occurrence of image blur and contour due to unnecessary intermediate colors, and suppression of occurrence of flicker and the like at the same time.

  FIG. 10 shows a specific example of the effect of the process of FIG. (A) is an original image in this example. For the sake of simplicity, it is assumed that, as an example, a black character ‘E’ is displayed on a white background. Each horizontal line portion (LX) of the character 'E' surrounded by a dotted line frame is arranged at a position where a luminance change occurs between the pixels of the pixel pair (PP). Accordingly, a condition for invalidating the pixel pair data correction (412) only for odd-numbered screens (Fo) is given as a correction condition (j3) for the pixel pair data correction (412) from the luminance edge processing function 406. (B) shows the result of pixel-to-data correction (412) when the correction condition (j3) based on the processing result of the luminance edge processing function 406 is not reflected. In each horizontal line portion (LX) of the character ‘E’ where flickering or the like occurs, an intermediate color is generated at a portion (901) illustrated in order to suppress the occurrence of flickering or the like. In the case of a pattern composed of thin lines such as characters as in this example, the intermediate color portion (901) may give a sense of image quality deterioration.

  On the other hand, (c) shows the result when the correction condition (j3) for the pixel pair data correction (412) is reflected from the luminance edge processing function 406. In each of the horizontal line portions (LX) of the character ‘E’, the luminance is lowered at the intermediate color portion added to suppress flicker and the like as shown in the portion (902) illustrated. For this reason, even in the case of a pattern composed of thin lines such as characters, there is no feeling of image quality deterioration and occurrence of flickering is suppressed.

<Edge pixel correction>
Next, referring to FIG. 11, the processing contents and effects of edge portion pixel correction (413) will be described. This processing content is common to each processing configuration of the first embodiment. As in the above (FIGS. 6 and 19), the image of the boundary portion of the diagonal line displayed as a still image is taken as an example. (B) ((b1) to (b3)) shows that the pixel pair (PP) has the same luminance (the luminance ratio (α) of the first condition (j1) is 1: 1) during interlaced display by the first technique. This is a case where drive display is performed simultaneously. (B1) is the original image (f). This is alternately and repeatedly displayed in the state of an odd screen (Fo) shown in (b2) and an even screen (Fe) shown in (b3). In each of these screens (Fo, Fe), it can be seen that a reduction in resolution due to enlargement of the pixels in the vertical direction has become apparent.

  On the other hand, (a) ((a1) to (a5)) shows the case of the processing of the present embodiment. In this edge portion pixel correction (413), with reference to the correction condition (j2) such as (a1) determined by the luminance edge processing function 406 for the input image (f) as (a2), Correction processing (edge pixel correction processing 413) is performed. In this example, the two-dimensional filter process is performed as the correction process. As described above (FIG. 6F), the correction condition (j2) shown in (a1) is based on the size of the circle, and the width of the input pixel range to the filter and the strength of the filter (the stronger the narrower the band) ). The result of correcting the input image (f) of (a2) (edge pixel correction processing 413) according to the correction condition (j2) is shown as an image (f2) of (a3). Here, the pattern attached to the area of each pixel unit has a higher luminance in the order of the oblique line pattern (k11), the dense dot pattern (k12), and the sparse dot pattern (k13). With this correction process, in each state of the odd screen (Fo) shown in (a4) and the even screen (Fe) shown in (a5), the luminance gradation (k12, k13) is applied to the boundary portion of the diagonal line pattern (k11). ) Occurs. As a result, (2) reduction in resolution due to the vertical expansion of the pixels is suppressed.

<Correction condition control (1)>
Next, FIG. 12 shows the processing contents for determining the correction condition (j2) by the luminance edge processing function 406. This is an example of the correction condition control process 410. (C) ((c1) to (c3)) shows an outline of the processing. The characteristic (E2) such as the intensity and direction of the luminance edge (E1) of each pixel, which is indicated by the arrow (vector) as described above (FIG. 6D) shown in (c1), is obtained. Based on the intensity of the luminance edge, a filter condition (filter coefficient: E3) as shown in (c2) is determined. Next, the obtained filter condition (E3) is optimized as shown in (c3) with reference to the direction of the luminance edge of each pixel and the screen polarity (Fo / Fe) at that time (optimization) Filter coefficient: E3 ′).

  (A) has shown the state which sampled the brightness | luminance edge intensity | strength (I) distribution 1101 contained in the whole display image as a histogram with a fixed period. Since the display image changes with time, the sampled luminance edge intensity (I) distribution 1101 also changes as shown in FIG. The luminance edge processing function 406 samples the luminance edge intensity (I) distribution 1101 at a constant period (update time: t1, t2,...) As shown in FIG. On the time axis (T), t is the current time. In the distribution 1101, h is the frequency with respect to the luminance edge intensity (I). Then, the in-screen luminance edge intensity range (range: r) 1104 is calculated from the maximum value (max) 1103 and the minimum value (min) 1102 of the luminance edge intensity (I) included in the screen at that time. Then, during the period until the next update of the luminance edge intensity (I) distribution 1101, the luminance edge intensity (i) of the pixel to be processed (current pixel) at the current time (t) is specified by the range (r) 1104. (Ranking). The normalized value (u) is i / r. In this case, the difference between the luminance edge intensity (i) of the current pixel and the minimum value (min) 1102 of the in-screen luminance edge intensity may be normalized by the range (r) 1104. After the luminance edge intensity (I) distribution 1101 is updated, normalization is performed using a newly obtained range (r) 1104.

  In this process, an index (s1) 1107 as shown in (b) is provided for the normalized value (u) obtained as described above, and the filter effect (filter characteristics) is set using the index (s1) 1107 as a reference value. ) Is selected. The index (s1) 1107 is a stepwise division. Therefore, in this apparatus, the index (s1) 1107 and the index (s2) 1108 for determining the filter characteristics are associated in advance. (B) shows an example of correspondence between the index (s1) 1107 and the index (s2) 1108 for determining the filter characteristics. In this example, the index (s1) 1107 has nine levels (0 to 8), and the filter characteristic index (s2) 1108 has seven types (1 to 7), and the correspondence between them is a solid line (corresponding function 1105). It is predetermined as follows. The larger the value of the filter characteristic index (s2) 1108, the stronger the filter effect (wide range and narrow band), and the smaller the value, the weaker (narrow range and wide band). The correspondence indicated by the dashed line (corresponding function 1106) corresponds to the case where the maximum value (max) 1103 of the luminance edge intensity (I) is small based on the correspondence of the solid broken line (1105). , The association characteristic of the index (s1) 1107 and the index (s2) 1108 is converted. Thereby, even when the normalized value (u) is the same index (s1) 1107, even when the maximum value (max) 1103 is different, it is possible to select the appropriate filter characteristic index (s2) 1108. .

  Next, in this process, the filter characteristic index (s2) 1108 obtained as described above is optimized with reference to the direction of the luminance edge and the polarity (Fo, Fe) of the screen. .

<Correction condition control (2)>
FIG. 13 ((a1) to (a11)) shows the optimization process and effect of the filter characteristic (index 1108) in a part of the correction condition control process 410. This optimization process is particularly effective when the luminance ratio (α) of the first condition (j1) at the time of two-line driving is not 1: 1. Therefore, in this example, the luminance ratio of the first condition (j1) is set to 1: 0.5, for example. (A1) is the original image (f), and the image of the boundary portion of the diagonal line is taken as an example as described above. The pattern of each pixel represents the intensity of luminance, and the luminance is higher in the order of k11, k12, and k13 as described above. When there is no optimization of the filter characteristics described in this example, the filter condition (filter coefficient: E3) 1221 is as shown in (a2), and the correction result image (f2) is (a3). ) The states of the odd screen (Fo) and the even screen (Fe) for the image (f2) are (a4) Fo and (a5) Fe.

  In the case of this example, the luminance ratio of the pixel pair is, for example, 1: 0.5. Therefore, when two lines are driven, the lighting states of Fo and Fe are (a6) Fo2 and (a7) Fe2. It becomes street. Here, the dotted curve attached in (a6) and (a7) is a contour line (1201) of the lighting intensity on each screen (Fo, Fe), and shows the shape perceived by the user (viewer). . (A6) In the case of Fo, the relationship between the lighting intensity between the pixels of the pixel pair (PP) is a relationship in which the upper (P1) side is strong and the lower (P2) side is weak, but the macroscopic intensity relationship is Since the strength increases from top to bottom, there is a conflicting relationship. Therefore, on the odd screen (Fo), the contour line (1201) of the lighting intensity becomes a comb shape, and the smoothness of the edge of the diagonal line is impaired.

  On the other hand, in the case of (a7) Fe, the relationship of the lighting intensity between the pixels of the pixel pair (PP) is weak on the upper (P2) side and strong on the lower (P1), and matches the macroscopic intensity relationship. . Therefore, on this even screen (Fe), the contour line (1202) of the lighting intensity becomes smooth. When the macroscopic intensity relationship is the reverse of this example, the phenomenon that the edge becomes comb-like occurs on the even-numbered screen (Fe) and smoothes on the odd-numbered screen (Fo). become. Therefore, from the combination of the direction of the luminance edge and the polarity of the screen, the position to be corrected is uniquely determined as in this example.

  (A8) shows the edge direction (edge feature: E2) calculated for each pixel of the image. In this process, the filter condition (E3) 1221 in (a2) is corrected to a filter condition (E3 ′) 1222 as shown in (a9) with reference to the edge direction. Here, the filter condition (E3) 1221 for the pixels having the inclination in the specific direction (the left downward vector of (a8) in this example) is uniformly weakened (smaller circle). By applying the corrected filter condition (E3 ′) 1222 to the original image (f) of (a1), a corrected image (f3) shown in (a10) is obtained. In this example, since the optimization is displayed based on the corrected image (Fo2) in which only the odd screen (Fo) is corrected, as shown in (a11), the corrected two-line driving time is displayed. An odd screen (Fo3) is obtained. The brightness contour line (1203) of this image becomes smooth with the comb-like unevenness like the Fo2 contour line (1201) of (a6) being suppressed.

  As described above, according to the first embodiment, when the power reduction or the like is performed using the two-line drive based on the interlaced display, the edge of the above (1) is performed by the two systems of processing by the correction function 401. It is possible to suppress the occurrence of flickering of the portion, and to suppress the occurrence of the decrease in resolution in the vertical direction (2).

(Embodiment 2)
Next, the PDP apparatus according to the second embodiment of the present invention will be described with reference to FIGS. In the above-described first embodiment, the configuration example using the two-dimensional filter processing as the correction means for suppressing the reduction in the resolution in the vertical direction (2) has been described. On the other hand, in the second embodiment, the basic device configuration and the like are the same as those in the first embodiment. For each pixel, it is determined whether the pixel is a stationary pixel or an operating pixel (moving part), and the correcting means is A configuration is adopted in which switching is applied between a stationary part and a moving part in an image. This is an example in which the effect of suppressing the reduction in the vertical resolution (2) is improved. In the edge portion pixel processing of the stationary portion, a target image with reduced image quality degradation is calculated from the original image.

<Correction processor (2)>
FIG. 14 shows the configuration of the correction processing unit 1400 in the second embodiment. The correction processing unit 1400 includes a memory unit 1404, a luminance calculation unit 1405, a luminance edge calculation unit 1406, an edge determination processing unit 1407, a correction processing condition table 1408, a pixel pair data processing unit 1409, a motion determination unit 1411, and a process selection control unit 1412. The edge pixel processing unit includes a first edge pixel processing unit (filter) 1413 and a second edge pixel processing unit (calculation) 1414.

  In the correction processing unit 1400, input image data (d1) 1401 of each pixel is temporarily stored in the memory unit 1404. In addition, the motion detection result 1402 of the pixel is also stored in the memory unit 1404 at the same time. Note that the motion detection is obtained in advance using a known motion detection method. The memory unit 1404 is configured to store data of a plurality of lines in units of one line for the image data (d1) 1401 and the motion detection result 1402 of each pixel. By this processing unit, pixel data on a plurality of lines is simultaneously read from a plurality of memories and input to the luminance calculation unit 1405 and the pixel pair data processing unit 1406. In addition, a motion detection result 1402 of each pixel corresponding to the read image data is also read simultaneously and input to the motion determination unit 1411. The motion determination unit 1411 determines the presence or absence of motion related to the pixel and outputs the result as a binary value (present “1” / not present “0”).

  As described above, the luminance edge calculation unit 1406 extracts luminance edges, and the edge determination processing unit 1407 extracts luminance edge features. Correction condition control (410) is performed based on the extracted luminance edge feature. In this example, the configuration is such that the correction conditions are selected and output from the correction processing condition table 1408 in which a plurality of correction conditions are stored by the output of the edge determination unit 1407. The result of the edge determination processing unit 1407 is reflected in the pixel pair data processing unit 1409. As described above, the second condition (f2) is given to the edge pixel processing units (1413, 1414), and the third condition (j3) is given to the pixel pair data correction unit 1409.

  In this example, two types (1413, 1414) are provided as edge part pixel processing parts. On the other hand, (1413) has the configuration of the filter processing described in the first embodiment (FIG. 6 (f) and the like), which is referred to as a first edge portion pixel processing portion (filter) 1413. The output (j2) from the correction processing condition table 1408 is reflected on the processing unit (1413). The other (1414) is a second edge pixel processing unit (calculation) 1414. These two processing units (1413, 1414) are effective in combination. These two types of edge portion pixel processing units (1413, 1414) are configured to be selected by a processing selection control unit (switch or the like) 1412 controlled by the output result of the motion determination unit 1411. In this example, when the amount of motion for the corresponding pixel is 0 (no motion), the processing unit selects the second pixel processing unit (calculation) 1414 to perform processing on the corresponding pixel, If the amount of motion is not 0, it is selected that the processing for the corresponding pixel is performed by the first edge portion pixel processing unit (filter) 1413. The second edge pixel processing unit (calculation) 1414 is obtained by calculating a target image from the original image.

<Second edge pixel processing unit>
In FIG. 15, the processing content of the second edge pixel processing unit (calculation) 1414 is shown. As described above, this processing is applied to a motion amount of 0, that is, a still image portion. In the still part in the image, the odd-numbered screen (Fo) and the even-numbered screen (Fe) are visually combined to form a still image with a high resolution, thereby suppressing a reduction in resolution in the vertical direction. . That is, in this process, pixels that are driven by two lines so that the effect of suppressing the reduction in vertical resolution is the highest in the image (G) obtained as a result of combining the odd screen (Fo) and the even screen (Fe). The display data of each pixel is corrected according to the condition (j1).

  (A) explains the relationship between the emission intensity of the pixels on Fo, Fe and their composite image (G) in the two-line drive during interlaced display. Let the luminance ratio of the first condition (j1) be α (α = 0 to 1). In the above two-line driving, the auxiliary pixel (P2) on the line (Le) adjacent to the main pixel (P1) on the line to be driven (for example, Lo at Fo) is changed to the main pixel on the lighting line (Lo) ( Based on the data of P1), the display is simultaneously driven with the luminance ratio (α) of the first condition (j1).

  In the pixel pair (PP) on the line pair (LP) to be driven by two lines, on the odd screen (Fo), for example, the pixel pA (P1) with a vertical line on the odd line (Lo) is lit with intensity a. At the same time, the pixel pB (P2) with a horizontal line is turned on with an intensity αa multiplied by a factor α with respect to pA (when both pA and pB are turned on). On the even-numbered screen (Fo), for example, the pixel pB (P1) on the even-numbered line emits light with an intensity b, and at the same time, the pixel pA (P2) is lit with an intensity αb that is a factor α times that of pB. On the composite image (G), the intensities of the pixels pA and pB are c and d (referred to as variables c and d). The intensities c and d are expressed by a determinant such as Expression (1).

  On the other hand, (b) shows the processing contents in the second embodiment. In the method of the second embodiment, the original image (f) is first processed to generate the target image (g). For this processing, general filter processing or the like can be applied. The intensities (targets) of the pixels pA and pB of the pixel pair (PP) on the target image (g) are set to ct and dt (set to variables ct and dt). The relationship of the determinant as shown in Equation (2) using the coefficients α as the first condition (j1) in the case of two-line driving, where the intensities of the pixels pA and pB on the original image (f) are a and b. The correction amounts Δa and Δb for satisfying the above are calculated by Expression (3) (Expression (3) is obtained by developing Expression (2)). The intensity of the pixels pA and pB is corrected by the calculated value. As a result, the composite image obtained when the two-line drive is performed substantially matches the target image (g).

  (C) has shown the synthesized image (G1, G2) obtained by each of the case where the process of Embodiment 2 is applied, and the case where it is not applied. A dotted line indicates a contour line of intensity, and a smoother contour line is obtained in the composite image (G2) when the second embodiment is applied than in the composite image (G1) when the second embodiment is not applied, and the reduction in vertical resolution is suppressed. It turns out that an effect is high.

(Embodiment 3)
Next, a PDP apparatus according to Embodiment 3 of the present invention will be described with reference to FIG. In FIG. 16, as the third embodiment, the basic apparatus configuration and the like are the same as those of the first embodiment, and the processing by the interpolation described above (FIG. 7, etc.) is not a linear function but a polynomial function. The example of a structure in the case of performing by is shown.

  (A) shows an example of an image 1700 to be displayed. The white portion has high luminance (K2) and the black portion has low luminance (K1). The luminance profile along the line segment AB of the image 1700 is as shown in (b). Further, the line connecting the points indicating the emission intensity for each pixel indicates the ideal value (1702) of the luminance profile along the line segment AB. As described above, each pixel is obtained by sampling the ideal value (1702) at the cycle of the pixel.

  (C) is a case where the correction value (1703) is calculated by interpolation using a linear function (eg, 604) as in the example described above (eg, FIG. 7). Here, interpolation is performed at an intermediate point between the pixels pA and pB (when the luminance ratio (α) is 1: 1). When interpolation is performed using a linear function as in this example, the calculated point (1703) may deviate greatly from the ideal value (1704) of the luminance profile indicated by a broken line connecting the points.

  In contrast to (c), in (d), as a characteristic process of the third embodiment, pixel data changes of a plurality of pixels arranged vertically in the vertical direction with respect to the target pixel are approximated as a polynomial in pixel coordinates. The case where interpolation is performed based on the result is shown. Here, a polynomial approximation function 1706 indicated by a solid line is calculated for a plurality of pixels arranged in the vertical direction along the line segment AB including the pixels pA and pB, and an interpolation point ( 1705). In this case, since the deviation between the polynomial approximation function 1706 and the ideal value 1707 of the luminance profile is small, the deviation of the interpolation point (1705) is also small, and the correction accuracy is improved.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The present invention is applicable to a display device such as a PDP device that performs multi-gradation display processing.

It is a figure which shows the whole structure of the correction | amendment function in the PDP apparatus of Embodiment 1 of this invention. It is a figure which shows the whole block structure in the PDP apparatus of Embodiment 1 of this invention. It is a figure which shows the structural example of PDP in the PDP apparatus of Embodiment 1 of this invention. It is a figure which shows the example of a field drive sequence in the PDP apparatus of Embodiment 1 of this invention. It is a figure which shows the structure of the correction process part in the PDP apparatus of Embodiment 1 of this invention. It is a figure which shows the example of the brightness | luminance edge process in the PDP apparatus of Embodiment 1 of this invention. It is a figure for demonstrating the content example (1) and effect of a pixel pair data correction process in the PDP apparatus of Embodiment 1 of this invention. It is a figure for demonstrating the content example (2) and effect of a pixel pair data correction process in the PDP apparatus of Embodiment 1 of this invention. FIG. 6 is a diagram for explaining an example in which the processing result of the luminance edge processing function is reflected as a correction condition (third condition) in the pixel-to-data correction process in the PDP device according to the first embodiment of the present invention. is there. It is a figure for demonstrating the effect of the example of FIG. 9 in the PDP apparatus of Embodiment 1 of this invention. It is a figure for demonstrating the content and effect of an edge part pixel correction process in the PDP apparatus of Embodiment 1 of this invention. It is a figure for demonstrating the processing content for determination of the correction conditions (2nd condition) by the brightness | luminance edge processing function in the PDP apparatus of Embodiment 1 of this invention. It is a figure for demonstrating the process and effect of a filter characteristic optimization in the PDP apparatus of Embodiment 1 of this invention. It is a figure which shows the structure of the correction process part in the PDP apparatus of Embodiment 2 of this invention. It is a figure for demonstrating the processing content of the 2nd edge part pixel process part in the PDP apparatus of Embodiment 2 of this invention. It is a figure for demonstrating the content of the pixel pair data correction process in the PDP apparatus of Embodiment 3 of this invention. (A)-(d) is a figure for demonstrating the interlace display in the PDP apparatus of a prior art. (A)-(e) is a figure for demonstrating the cause of generation | occurrence | production of the flicker of the edge part of an image, etc. by the display by the 1st technique (2 line drive) in the PDP apparatus of a prior art. (A)-(c) is a figure for demonstrating the state of the vertical direction resolution degradation of the image by the display by the 1st technique (2 line drive) in the PDP apparatus of a prior art. (A), (b) is a figure for demonstrating the usage relationship etc. of the display data by the display by a 1st technique (2 line drive) in the prior art PDP apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... PDP, 21 ... Front substrate, 22 ... Back substrate, 23,26 ... Dielectric layer, 24 ... Protective layer, 27 ... Partition wall, 28 ... Phosphor, 31 ... X electrode, 32 ... Y electrode, 33 ... Address electrode , 71 ... Reset period, 72 ... Address period, 73 ... Sustain period, 100, 1400 ... Correction processing unit, 101, 601, 1701 ... Still image, 204, 205 ... Pixel pair, 301, 304, 307 ... Odd screen (Fo ), 302, 305, 308 ... even screen (Fe), 303, 306, 309 ... composite image, 401 ... correction function (correction processing function), 402, 403 ... processing, 404 ... image data (d1), 405 ... 1 condition (j1), 406 ... luminance edge processing function, 407 ... luminance conversion processing, 408 ... luminance edge portion extraction processing, 409 ... luminance edge feature extraction processing, 410 ... correction condition system Processing, 411: Pixel data correction processing function, 412 ... Pixel pair data correction processing, 413 ... Edge portion pixel correction processing, 603, 803, 1703, 1705 ... Interpolated interpolation data (correction value), 604, 804 ... Linear function, 605, 805, 905 ... pixel pairs, 804 ... polynomial, 901, 902 ... pixels, 1101 ... luminance edge intensity distribution, 1102 ... minimum value (min), 1103 ... maximum value (max), 1104 ... range (r), 1105 , 1106 ... corresponding function, 1107 ... index (s1), 1108 ... index (s2), 1201 to 1203 ... luminance contours, 1221, 1222 ... filter conditions, 1300 ... image data processing unit, 1301, 1401 ... image data (d1) 1302 ... Scan controller unit, 1303 ... Data controller unit, 1304 ... Image processing program 1304 ... Y sustain pulse controller 1307 ... Y sustain circuit 1308 ... Scan driver 1309 ... Address driver 1310 ... X sustain pulse controller 1311 ... X sustain circuit 1314 1404 ... Memory unit, 1315, 1405 ... Luminance calculation unit, 1316, 1406 ... Luminance edge calculation unit, 1318, 1408 ... Correction processing condition table, 1319, 1409 ... Pixel pair data processing unit, 1320 ... Edge portion pixel processing unit, 1402 ... Motion detection result, 1411 ... motion determination unit, 1412 ... process selection control unit, 1413 ... first edge unit pixel processing unit, 1414 ... second edge unit pixel processing unit, 1702, 1704, 1707 ... ideal value, 1706 ... polynomial approximation function.

Claims (15)

A plasma display panel driving method for displaying a multi-gradation moving image on the basis of input display data for a plasma display panel having a display area constituted by an odd and even display line group and a pixel matrix. ,
Based on the display of one of the odd and even lines in the display area, and based on the display data of one first line for one or more line pairs, When simultaneously driving and displaying the pixels of the other second line at the luminance of the luminance ratio of the first condition,
A correction condition for correction processing for correcting display data of the target line pair or pixel pair is determined based on the first condition, and display data of the target line pair or pixel pair is corrected based on the correction condition. Perform the correction process,
In the correction process, the luminance at the light emission centroid position between the two pixels of the pixel pair according to the luminance ratio of the first condition is set so that the luminance change between the two pixels of the pixel pair becomes gentle. A method of driving a plasma display panel, wherein correction is made so that the total luminance of the two pixels of the pixel pair at the time of individual simultaneous light emission substantially coincides. A plasma display panel driving method for displaying a multi-gradation moving image on the basis of input display data for a plasma display panel having a display area constituted by an odd and even display line group and a pixel matrix. ,
Based on the display of one of the odd and even lines in the display area, and based on the display data of one first line for one or more line pairs, When simultaneously driving and displaying the pixels of the other second line at the luminance of the luminance ratio of the first condition,
Luminance data for each pixel of an image to be displayed is acquired based on the input display data, an edge portion where a predetermined luminance change occurs and a feature thereof are extracted based on the luminance data, and the edge portion is characterized based on the feature of the edge portion. Determining a correction condition for correcting the display data of the pixel of the image, and performing a correction process of correcting the display data of the pixel of the image based on the correction condition;
In the correction process, the display data of the pixels of the edge portion in the image to be displayed is corrected according to the feature of the edge portion so as to suppress degradation of the resolution in the second direction of the image. A method for driving a plasma display panel. A scanning electrode and a common electrode are provided in the first direction, and an address electrode is provided in the second direction intersecting with the scanning electrode and the common electrode. A plasma display panel having a display area configured by a display cell matrix associated with a pixel, and a field serving as a unit for displaying an image frame in the display area is a plurality of subfields for gradation expression And the subfield includes an address period for selecting a cell and a sustain period for sustaining discharge of the selected cell, and the display is performed by selectively lighting a plurality of subfields of the field based on input display data. A plasma display device displaying a multi-tone image group in an area,
Means for driving one display of the odd and even line groups of the display area in a time-sharing manner;
For one or more line pairs, based on the display data of one first line, the pixel of one first line is compared with the pixel of the other second line and the luminance of the luminance ratio of the first condition First means for simultaneously driving and displaying,
In driving display by the first means,
A process of determining a luminance ratio of the first condition;
A process for determining a correction condition for a correction process for correcting display data of a line pair or a pixel pair to be driven by the first means based on the first condition;
Correction means for correcting display data of the line pair or pixel pair to be driven based on the correction condition;
In the correction process, the luminance at the light emission centroid position between the two pixels of the pixel pair according to the luminance ratio of the first condition is set so that the luminance change between the two pixels of the pixel pair becomes gentle. , And correct so that the total luminance at the time of individual simultaneous light emission of the two pixels of the pixel pair substantially match,
A plasma display device, wherein the panel is driven and displayed by the corrected display data. The plasma display device according to claim 3, wherein
The second means performs, as the correction process, a weighted average process between the target pixel and its surrounding pixels for each pixel to be corrected, and determines a coefficient of the weighted average process as the correction condition. A plasma display device. The plasma display device according to claim 3, wherein
In the second means, a data value at an arbitrary position between the two pixels of the pixel pair is obtained based on a linear function of coordinates between the two pixels according to the luminance ratio of the first condition. In addition, the plasma display apparatus is characterized in that the correction processing is performed using the data value of the point calculated as a point to be interpolated. The plasma display device according to claim 3, wherein
In the second means, in accordance with the luminance ratio of the first condition, a plurality of data values at arbitrary positions between the two pixels of the pixel pair are arranged in the second direction including the two pixels. A point of interpolation is calculated based on a result obtained by approximating a change in a plurality of pixel data including a pixel as a polynomial of coordinates, and the correction process is performed using a data value of the point. Plasma display device. The plasma display device according to claim 3, wherein
In the second means, referring to a positional relationship between the pixel pair and a specific part where a predetermined luminance change occurs between two pixels of the pixel pair in the image, the correction is performed as the correction condition. A plasma display device characterized by determining whether processing is valid or invalid. A scanning electrode and a common electrode are provided in the first direction, and an address electrode is provided in the second direction intersecting with the scanning electrode and the common electrode. A plasma display panel having a display area configured by a display cell matrix associated with a pixel, and a field serving as a unit for displaying an image frame in the display area is a plurality of subfields for gradation expression And the subfield includes an address period for selecting a cell and a sustain period for sustaining discharge of the selected cell, and the display is performed by selectively lighting a plurality of subfields of the field based on input display data. A plasma display device displaying a multi-tone image group in an area,
Means for driving one display of the odd and even line groups of the display area in a time-sharing manner;
For at least one line pair, one pixel of the first line is simultaneously driven and displayed with the luminance ratio of the first condition using the display data of the first line with respect to the pixel of one first line. Having first means to
In driving display by the first means,
Processing for obtaining display data including luminance data for each pixel of an image to be displayed based on input display data;
Based on the luminance data, processing for extracting an edge portion where a predetermined luminance change occurs and its characteristics;
Processing for controlling and determining correction conditions for correcting display data of the pixels of the image based on the characteristics of the luminance edge portion;
Correction processing for correcting display data of pixels of the image based on the correction condition, and third means for performing correction processing,
In the correction process, in order to suppress degradation of resolution in the second direction of the image, correction is performed in accordance with the feature of the edge portion of the display data of the pixel of the edge portion in the display target image,
A plasma display device, wherein the panel is driven and displayed by the corrected display data. The plasma display device according to claim 8, wherein
The third means performs, as the correction process, a weighted average process of the target pixel and its peripheral pixels for each pixel to be corrected, and determines a coefficient of the weighted average process as the correction condition. A plasma display device. The plasma display device according to claim 8, wherein
The third means refers to a range of luminance change included in the entire image to be displayed, and normalizes the magnitude of luminance change at the position of each pixel to be corrected with respect to the range. A correction condition for the correction process is determined based on the normalized value. The plasma display device according to claim 8, wherein
The third means refers to the direction of the luminance change at the position of each pixel to be corrected and the polarity of the odd or even screen in the display of the image to be displayed, and sets the correction condition. A plasma display device characterized by being determined to be optimized. The plasma display device according to claim 8, wherein
The third means refers to the movement of each pixel targeted for the correction process, and selects the correction process based on the movement of the pixel. The plasma display device according to claim 12, wherein
When the amount of movement is 0, the third means performs the correction process as follows:
A correction amount is provided for an added image of odd and even screens reflecting the luminance ratio of the first condition in the line pair or pixel pair to be driven by the first means, and the addition is performed in consideration of the correction amount A plasma display apparatus characterized in that a process for calculating the correction amount is performed so that an image and a target image with little deterioration in image quality with a moderate luminance change at an edge portion substantially coincide with each other. A scanning electrode and a common electrode are provided in the first direction, and an address electrode is provided in the second direction intersecting with the scanning electrode and the common electrode. A plasma display panel having a display area configured by a display cell matrix associated with a pixel, and a field serving as a unit for displaying an image frame in the display area is a plurality of subfields for gradation expression And the subfield includes an address period for selecting a cell and a sustain period for sustaining discharge of the selected cell, and the display is performed by selectively lighting a plurality of subfields of the field based on input display data. A plasma display device displaying a multi-tone image group in an area,
Means for driving one display of the odd and even line groups of the display area in a time-sharing manner;
For one or more line pairs, based on the display data of one first line, the pixel of one first line is compared with the pixel of the other second line and the luminance of the luminance ratio of the first condition First means for simultaneously driving and displaying,
In driving display by the first means,
A process of determining a luminance ratio of the first condition;
A process for determining a correction condition for a correction process for correcting display data of a line pair or a pixel pair to be driven by the first means based on the first condition;
Correction means for correcting display data of the line pair or pixel pair to be driven based on the correction condition;
In the second means, a data value at an arbitrary position between the two pixels of the pixel pair is obtained based on a linear function of coordinates between the two pixels according to the luminance ratio of the first condition. In addition, the point is calculated as a point to be interpolated, and the correction process is performed using the data value of the point.
A plasma display device, wherein the panel is driven and displayed by the corrected display data. A scanning electrode and a common electrode are provided in the first direction, and an address electrode is provided in the second direction intersecting with the scanning electrode and the common electrode. A plasma display panel having a display area configured by a display cell matrix associated with a pixel, and a field serving as a unit for displaying an image frame in the display area is a plurality of subfields for gradation expression And the subfield includes an address period for selecting a cell and a sustain period for sustaining discharge of the selected cell, and the display is performed by selectively lighting a plurality of subfields of the field based on input display data. A plasma display device displaying a multi-tone image group in an area,
Means for driving one display of the odd and even line groups of the display area in a time-sharing manner;
For one or more line pairs, based on the display data of one first line, the pixel of one first line is compared with the pixel of the other second line and the luminance of the luminance ratio of the first condition First means for simultaneously driving and displaying,
In driving display by the first means,
A process of determining a luminance ratio of the first condition;
A process for determining a correction condition for a correction process for correcting display data of a line pair or a pixel pair to be driven by the first means based on the first condition;
Correction means for correcting display data of the line pair or pixel pair to be driven based on the correction condition;
In the second means, in accordance with the luminance ratio of the first condition, a plurality of data values at arbitrary positions between the two pixels of the pixel pair are arranged in the second direction including the two pixels. Based on the result of approximating the change of a plurality of pixel data including pixels as a polynomial of coordinates, it is calculated as a point for interpolation, and the correction process is performed using the data value of that point,
A plasma display device, wherein the panel is driven and displayed by the corrected display data.

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