JP2000105565A - Halftone display method and diplay device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actively utilize the redundancy to reduce the generation of the dynamic image false profile (color false profile) of an image itself by selecting a light emitting block used for the gradation display of an optional first picture element according to a procedure predetermined from the using state of the light emitting block in a second picture element adjacent thereto. SOLUTION: In the image of a frame at a certain point of time (time 0), picture elements (a)-(d) perform a gradation display by using (lighting) two light emitting blocks D (light emitting blocks having the largest weight of luminance), and a picture element (e) performs a gradation display as displayed by 160-BB (a picture element displaying 160 gradation levels by use of three light emitting blocks of 48 gradation levels). Picture elements on and after a picture element (f) also perform the gradation display by use of three light emitting blocks according to a procedure predetermined according to the number of light emitting blocks in the picture element on the left. Further, in the image of the following frame (1F), the same gradation display is performed when the image is moved from the right to the left at a speed of 3 picture elements/ frame.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a halftone display method and a display device for displaying a halftone by a time division method within a frame or a field, and more particularly, to a method for improving halftone disturbance occurring in a moving image portion of a gas discharge panel. The present invention also relates to a halftone display method and a display device for preventing generation of a false contour of a moving image (color false contour).

In recent years, as display devices have become larger, thinner display devices have been required, and various types of thin display devices have been provided. For example, a matrix panel for displaying a digital signal as it is, that is, a gas discharge panel such as a plasma display or a DMD (Digital Micromirror Deviator).
ce), matrix panels such as EL display elements, fluorescent display tubes, and liquid crystal display elements are provided. Among such thin display devices, the gas discharge panel has a large screen because of its simple process, the screen can be easily enlarged, the self-luminous type has good display quality, and the response speed is fast. It is considered as a leading candidate for a direct-view type HDTV (high definition television) display device. However, in such a display device, in particular, there is a problem that a halftone display of a moving image portion is disturbed and display quality is impaired. In contrast, a positive or negative equalizing pulse is superimposed on an original signal. To reduce false contours. However, as the moving speed of the image increases, the disturbance of the image becomes visible. Accordingly, a halftone display technique has been proposed in which halftone display is not disturbed even for a moving image having a high moving speed, but further improvement in display quality is demanded.

[0003]

2. Description of the Related Art Conventionally, a halftone display method of a memory type gas discharge panel is performed by a time division method within a frame or a field, and one frame (or one field: each defines a 60 Hz cycle, for example). A period) is composed of N screens (sub-frames: light-emitting blocks) having different luminance weights. The field is, for example,
In the case where an interlaced operation is performed, this is a name of a device that composes one frame with two fields, or a device that composes one frame with a plurality of fields in another display operation (display processing). It is equivalent to a frame.

Conventionally, a sub-frame (light-emitting block) is
SF0, SF1, SF from the side with the smaller luminance weight
2, ..., called SF (N-1), the ratio of the weight of their brightness 2 ^0, 2 ^{1, 2} 2, and has a ... 2 ^N-1. The halftone luminance in one frame is determined by selecting the presence or absence of light emission in these subframes. The luminance perceived by the human eye is determined by the visual characteristics of human eyes, that is, the afterglow characteristics. It is represented by the sum of each luminance. At this time, there are 2 ^N combinations of light emission within one sub-frame, that is, halftone numbers that can be expressed. The lighting sequence of the subframe to which the present invention can be applied is, for example, a sequence having redundancy that allows one gradation display as shown in FIG. 19 described later to be expressed by a combination of a plurality of subframes. In Although,
First, the ratio of the luminance weight of each subframe is 2 ⁰ , 2 ¹ ,
The description will be started from the lighting sequence of 2 ² ,..., 2 ^N−1 .

FIG. 1 is a diagram showing an example of a conventional lighting sequence of each sub-frame, and shows a lighting sequence in one frame when the above-described conventional halftone display method is used. As shown in FIG. 1, one frame (1
The field (field) is composed of eight (N = 8) subframes (light emission blocks) having different luminance weights, and are called SF7, SF6,..., SF0 in descending order of the luminance weight. Here, SF7 is the most significant bit (MSB) side,
SF0 is called the least significant bit (LSB) side. Each subframe includes SF0, S in one frame.
F1,..., And SF7 are arranged in ascending order of luminance weight.

However, in the case of a lighting sequence in which subframes are arranged in a row as shown in FIG. 1 (in the case of 256 gradations), it is determined whether there is no overlap between light emitting subframes at the same luminance level. Alternatively, when the intermediate gray level which is short in time is alternately lit for each frame, the light emission of the cell becomes a half cycle of the frame frequency and flicker occurs, and display quality is significantly impaired. Are known.

FIG. 2 is a diagram showing an example of the lighting state of each sub-frame when the intermediate gradation levels are 127 and 128. As is clear from FIG. 2, at the intermediate gradation level 127, all of the sub-frames SF0 to SF6 are turned on and SF7 is turned on.
Is not lit, and at the intermediate gray level 128, only the subframes SF0 to SF6 are not lit and only the SF7 is lit.

That is, as shown in FIG. 2, for example, when the intermediate gradation levels 127 and 128 are alternately turned on for each frame, a period of one frame, a period of no light and a period of light are alternately repeated. Will be
As a result, the lighting period becomes a half of the frame period, and flicker occurs. Such a display in which specific intermediate gradation levels are alternately repeated is performed between frames (between frames or fields), for example, when A / D conversion is performed on analog video display data of a portion where the luminance is gradually changing. Are constantly generated due to the influence of the conversion error and noise in. For this reason, there has been a problem that conversion errors and noise during A / D conversion are amplified and displayed as flicker, thereby deteriorating the image quality.

On the other hand, conventionally, as a halftone display method for improving the flicker, for example, Japanese Patent Laid-Open
As shown in JP-A-145691, the subframe arrangement is defined as SF0, SF2, SF4, SF6, SF7, S
It has been proposed to improve by arranging like F5, SF3, SF1. In the halftone display of FIG. 1,
If the luminance levels are the same and there are no overlapping sub-frames that emit light, or if halftone levels that are short in time are displayed side by side, flickers will occur at those boundaries and the display quality will be poor. Is significantly inhibited. It is known that the display quality is more severely inhibited as the luminance is higher. Therefore, in order to improve the flicker, for example, as shown in Japanese Patent Application Laid-Open No. 4-127194, the light emission of the uppermost sub-frame is divided into two and arranged with a smaller sub-frame interposed therebetween. Has been proposed.

In the above-mentioned halftone display method,
The lack of smoothness in the motion of the moving image portion impairs the video quality is described in, for example, Japanese Patent Application Laid-Open No. 5-127612.
And a method of improving the same has been proposed. Japanese Patent Application Laid-Open No. 5-127612 discloses a halftone display method, in which an input section of an input image signal having a frame frequency of 70 Hz or less is provided with a means for doubling the frame frequency of the display device, and the frame frequency is doubled. , One or more regular bit subframes for displaying normal bits including a subframe for displaying the most significant bit, and one or more non-normal bit subframes for displaying bits less than the normal bits. It is configured to have a frame. For a still image portion, a frame having a double frame frequency is processed in units of two frames, and for a moving image, a halftone is displayed in a frame having a double frame frequency in units of one frame. Further, an image signal (display signal) is newly created based on an input image signal in order to newly create display data of a frame having a double frame frequency.

FIG. 3 is a diagram for explaining a lighting state in the first frame and the second frame. In FIG. 3, reference numeral 31 indicates a first frame, 32 indicates a second frame, and first and second frames 31 and 32 indicate frames whose frame frequency has been doubled. Here, a sub-frame set to have the same luminance weight between frames is referred to as a normal bit sub-frame, and 31
a, 31b, 32a, 32b. The other subframes are referred to as irregular bit subframes.

In the above-described prior art, halftone disturbance is improved in the display of a still image and a moving image part with a slow movement, but the disturbance of the halftone still occurs in a moving part with a fast movement. This halftone disturbance generating mechanism is based on the assumption that the number of subframes in a frame is six and the subframe arrangement in the frame is SF5, SF4, SF
The case of 3, SF2, SF1, SF0 (64 gradations) will be described with reference to FIGS.

FIG. 4 is a diagram for explaining an example of the cause of the halftone luminance disturbance in an example of the conventional halftone display method. FIG. FIG. 6 is a view for explaining another example of the cause of disturbance of halftone luminance in an example of a conventional halftone display method, and FIG. 7 is a view for explaining another example of a halftone level of 31. FIG. 35 is a diagram illustrating an example of a separated state of subframes when the number of subframes changes from 32 to 32.

As shown in FIG. 4, for example, in a display in which one blue vertical line of SF5 is turned on, a display is scrolled from right to left, and one frame (field) is displayed.
When one pixel is moved, the line appears to be moving on a cell of another color that is not lit, and a smooth movement is observed. This smooth motion is observed even when the number of pixels moving in one frame is considerably large, and this phenomenon is called apparent motion or β motion in the field of psychology.

Next, one vertical blue line SF5, SF4
When the display in which is turned on is scrolled from the right side to the left side by one pixel per frame, it is observed that the light emission of the sub-frame is displayed spatially separated as shown in FIG. For convenience, the light emission of SF5 is represented on the blue cell (B), but for the same reason as described above, the light emission moves as if on the red cell (R) and the green cell (G). looks like.

This is because, for example, SF4 is delayed about 2 msec from the display data writing period after SF5 is turned on.
This is because when the light is emitted, the light emission of SF5 moves in the scroll direction due to the apparent movement described above, and human eyes recognize as if the light emission of SF4 is following the light emission of SF5. Similarly, when all the sub-frames are turned on and scrolled in one frame, as shown in FIG. 5, the light emission of SF5 to SF0 appears to be spatially separated and emitted in one pixel.

FIG. 6 shows the result of observation when the pixel is moved by 2 pixels in one frame. In this case, the distance between the cells that actually emit light is 2 pixels and the movement distance is increased by the apparent movement. The speed of the moving light increases. Therefore, for example, when SF4 emits light with a time delay of about 2 msec after SF5 emits light, the light-emitting portion of SF5 has moved farther, and the spatial light-emitting interval of the subframe has increased. Looks like. From such observation results, it is understood that the spatial spread (separation) of the sub-frame at the time of occurrence of the apparent motion spreads within the pixel moved during the period of one frame.

Therefore, the light emission of each sub-frame which should be emitted by the same cell is different in the moving image part (cell).
, And the halftone luminance of the cell cannot be expressed by the sum of the subframes. As a result, the halftone luminance is disturbed in the moving image portion. As a specific example, when a monochromatic gradation display is scrolled in a gradient direction, a bright line or a dark line is generated at a boundary portion of a specific intermediate gradation level. This will be described with reference to FIGS.

In a display method in which the number of sub-frames in a frame (field) is six and the arrangement is from the top of the frame in the order of brightness, the intermediate gradation level is changed from the left side to the right side of the display screen. When the increasing blue gradation display is performed and scrolling is performed in the gradient direction of high luminance, that is, scrolling to the right, a dark line is generated at the boundary between the intermediate gradation levels where the number of lighting of the sub-frames is largely different. Specifically, for example, a dark line is generated at the boundary at the intermediate gradation levels 31 and 32, 15 and 16, 7 and 8, and the like. FIG. 7 schematically shows a state of a dark line generated at the boundary between the intermediate gradation levels 31 and 32 when the pixel is moved by two pixels per frame.

As shown in FIG. 7, in the moving image portion, spatial separation of sub-frames occurs, so that a cell that does not emit light at the boundary between the intermediate gradation levels 31 and 32 corresponds to one pixel. As a result, dark lines are generated. Further, when scrolling in the direction of a gradient with low luminance, that is, scrolling to the left, as shown in FIG.
And 32, the light emission is high and the brightness is high, resulting in a bright line. As shown in FIG. 9, even when scrolling to the right, scrolling in the gradient direction of low luminance causes the boundary between the intermediate gradation levels 31 and 32 to emit light densely and have high luminance. Will occur.

Here, if a single color display or a display without a color, that is, if the lighting sub-frame is the same for each color in a pixel, the disturbance of the halftone generated in the moving image portion occurs as a bright line or a dark line, and the display of the intermediate color is performed. That is, if the lighting sub-frame is different for each color in the pixel, a color different from that at the time of stationary occurs. A mechanism of generating a false contour of a moving image (color false contour) generated when a moving image is displayed by applying the above-described conventional technique will be described in detail with reference to FIGS.

FIG. 10 is a view showing a state where the display image is scrolled. FIG. 10 (a) shows a state where the display image is scrolled one pixel per frame from left to right, and FIG. 10 (b). Indicates a state in which the display image is scrolled by one pixel per frame from the right side to the left side. Here, in FIGS. 10A and 10B, the vertical axis represents time t, and the horizontal axis represents spatial position x. Also, 1F to 4F indicate frames (fields).

FIG. 11 is a diagram for explaining a problem that occurs when the display image is scrolled from left to right, and FIG. 12 is a diagram for explaining a problem that occurs when the display image is scrolled from right to left. It is. FIG.
As shown in FIG.
7 from the left to the right with 7 displayed side by side
When one pixel is moved per frame, the human eye has the property of following a moving object, so the coordinate origin on the retina moves on the broken arrow (ROR) in the figure. In this state, the coordinates on the retina are fixed, and the figure is redrawn as shown in FIG.
1 (a). The scale on the horizontal axis in FIG. 11A indicates the position on the retina, and the distance (length on the retina) that the display image moves in one frame period is 1.

Similarly, as shown in FIG.
If the state in which the intermediate gradation levels 128 and 127 are displayed side by side moves one pixel per frame from the right to the left, the human eye has the property of following a moving object. It moves on the dashed arrow (ROL) in the middle. FIG. 12A shows this state in which the coordinates on the retina are fixed and the figure is rewritten. In addition,
The scale on the horizontal axis in FIG. 12A is the same as the scale on the horizontal axis in FIG.

Here, the intermediate gray level 127 is a state in which all the sub-frames SF0 to SF6 are turned on and only the sub-frame SF7 is not turned on. In this state, only SF7 is turned on. FIG. 11A and FIG.
In FIG. 2A, the discharge cells are not provided with an area for the sake of simplicity.

First, as shown in FIG. 11B, when the display image is scrolled from left to right while the intermediate gradation levels 128 and 127 are displayed side by side, the image is located at the position (x) on the retina. The luminance K (x) will have a gap between the halftone levels 128 and 127. As a result, as shown in FIG. 11C, the stimulus amount L (x) on the retina falls (shows a valley) in the gap between the intermediate gradation levels 128 and 127.

That is, as shown in FIG. 11C, x = 2.5 to 3.5, 3.5 to 4.5, 4.5 to 4.5.
The integral value of each stimulus amount of 5.5 is represented by L (1), L
Assuming that (2) and L (3), L (1) ≒ L (3) >> L (2). That is, the intermediate gradation level 1
A dark line DL occurs at the boundary between 28 and 127. This phenomenon is the mechanism for generating halftone disturbances.

The stimulus amount L (x) on the retina is represented by the following equation.

[0029]

(Equation 1)

Here, λ indicates an arbitrary integer. Note that the integration range in the above equation is from λ−0.5 to λ +
Although it is set to 0.5, the way of setting this integral range is arbitrary, and it is desirable to make it approximately equal to the range in which halftone disturbance occurs. Next, as shown in FIG. 12B, when the display image is scrolled from right to left in a state where the intermediate gradation levels 128 and 127 are displayed side by side, the luminance K at the position (x) on the retina is obtained. In (x), the intermediate gradation levels 128 and 127 are continuous. as a result,
As shown in FIG. 12C, the stimulus amount L on the retina
(X) shows a peak at the boundary between the intermediate gradation levels 128 and 127.

That is, as shown in FIG. 12C, x = 2.5 to 3.5, 3.5 to 4.5, 4.5 to 4.5.
The integral value of each stimulus amount of 5.5 is represented by L (1), L
Assuming that (2) and L (3), L (1) ≒ L (3) << L (2). That is, the intermediate gradation level 1
A bright line BL is generated at the boundary between 28 and 127.

This is because, when the intermediate gray level having a color is moved, for example, the green intermediate gray levels 128 and 12 are shifted.
7. When only the red halftone level 64 is moved from right to left, a dark line is generated at the green halftone level boundary, but red is constant because there is no halftone level boundary. At the luminance level (gradation level). That is, since a person recognizes the result of combining the colors, the green dark line portion is conspicuously red, and a color outline is generated.

The above-mentioned phenomenon occurs remarkably in the skin color portion where the intermediate gradation level changes smoothly, and the red and green contours (color false contours) appear on the cheek portion in the image of the person looking back.
Will occur. That is, for example, in a plasma display panel (PDP), when a moving image is displayed, the image is disturbed by an afterimage effect of the eyes. This disorder is
Usually, it is particularly noticeable in the outline of the face and the like, and is called a moving image false outline, which is a major cause of deterioration of the image quality of the PDP. At present, as a technique for making false contours of a moving image inconspicuous, the number of gradations is reduced, and a superposition process is further performed.
Then, the number of gradations reduced by the above processing is raised to 256 gradations by performing error diffusion processing. However, if these methods are used, natural image expression cannot be performed. Therefore, in order to express a natural image up to a low gradation part, it is necessary to reduce a false contour of a moving image without reducing the number of gradations.

Therefore, the present inventors have disclosed in Japanese Patent Application Laid-Open
In Japanese Patent Application Laid-Open No. 39828/1991, when the gradation level of each pixel changes, a light-emitting block (equalization pulse) for adjusting brightness predetermined for each pixel according to the state of the change.
A halftone display method and a display device that add or reduce the halftone are proposed.

[0035]

FIG. 13 is a diagram for explaining a conventional halftone display method proposed in Japanese Patent Application Laid-Open No. 10-39828. FIG. 13A shows the light emission state I (t) of the discharge cell when the display gradation changes from the 127 level to the 128 level, and the horizontal axis t indicates time. As shown in FIG. 13A, the first 2
The frames (fields: 1F and 2F) have 127 levels, and the next two frames (3F and 4F) have 128 levels.

Observing the light emitting state I with human eyes,
The retinal stimulation intensity P (t) is as shown in FIG.
The retinal stimulus intensity P periodically changes between P1 and P2 during the period in which the 127 level is displayed, but at the beginning of the frame (3F) in which the 128 level is displayed, this value is lower than P2. I will. Furthermore, if the 128-level frame (4F,...) Continues for a sufficiently long time, the stimulus intensity returns to the oscillation between P1 and P2 again.

Due to the phenomenon that the retinal stimulus intensity P temporarily decreases, halftone is disturbed and observed in the eyes. The visually perceived intensity B (t) is obtained by integrating the intensity P (t) for stimulating the retina over a period of time similar to the afterimage, and is substantially as shown in FIG. In the figure, if the relationship of S1 <S2 <S3 is satisfied, no halftone disturbance is observed. However, FIG. 13C clearly does not satisfy this relationship. In this case, the boundary of the gradation appears darker than the original image.
Here, the intensity ΔS is supplemented to S2, and S1 <S2 + ΔS <
If S3, the halftone is not disturbed.

Therefore, according to the halftone display method proposed in Japanese Patent Application Laid-Open No.
An equalization pulse EP represented by (d) is added. FIG. 13E shows the retinal stimulation intensity P (t) by the equalizing pulse EP.
FIG. 13F shows the intensity B (t) visually recognized. FIGS. 13 (g) and 13 (h) show the light emission intensity I (t), retinal stimulus intensity P (t), and visible intensity B (t) as a result of adding such an equalization pulse EP, respectively. ,
And FIG. 13 (i).

As is clear from the comparison between FIG. 13C and FIG. 13I, it can be seen that the disturbance of the visible light emission intensity is reduced by adding the equalizing pulse EP (EPA). Here, the inserted equalization pulse EP may be negative (EPS). In this case, the width of the light-emitting block is reduced to reduce the luminance. The insertion of such an equalizing pulse is realized by, for example, a circuit shown in FIG.

FIG. 14 is a block diagram showing an example of a conventional luminance adjusting light emitting block insertion circuit. In FIG. 14, reference numeral 310 denotes a frame memory for giving a delay of one vertical synchronization period (1 V), 400 denotes a light emission block adding circuit for adjusting luminance, 410 denotes an equalizing pulse discriminating circuit, and 420 denotes an additional equalizing pulse. The circuit is shown. FIG.
In the luminance adjustment light emitting block insertion circuit shown in FIG.
And look-up table (LUT: ROM) 410
b, and the equalizing pulse adding circuit 420 is configured as an adding unit (adding circuit). Comparison section 41
0a is a comparison between the bit data of the n-th frame and the bit data of the (n + 1) -th frame following the n-th frame. "-1" is output for a bit turned on from "1", and "0" is output for a bit whose data has not changed between both frames.

The LUT 410b is configured as, for example, a ROM in which predetermined data is written in advance,
A predetermined (pre-written) equalization pulse is generated according to the output of Oa. The equalization pulse output from the LUT 410b has positive and negative signs. The adder 420 adds an equalizing pulse (signed with a positive or negative sign) to the original signal (display data 210) (if the equalizing pulse is negative, the equalizing pulse is reduced). A display signal (220) is output.

A conventional halftone display method (equalized pulse method) proposed in Japanese Patent Application Laid-Open No. 10-39828.
Is excellent in that the total luminous flux input to the eye is equal to the original signal. That is, S2 in FIG.
In the section of + ΔS, the total amount is substantially equal to S1 or S3, though the intensity that is visually recognized varies with time. Therefore, when the displayed image is viewed sufficiently away from the display device (PDP screen), the disturbance of the halftone cannot be visually recognized, and the disturbance of the halftone luminance is improved.

By the way, the content "the total luminous flux is equal to the original signal" is correct for a still image and a moving image, but has a spatial intensity which is visually recognized for a fast moving image. If the uniformity becomes severe, satisfactory image quality cannot always be obtained. In view of this, the present inventors have proposed, in Japanese Patent Application Laid-Open No. Hei 10-133623, a halftone display method and a display device capable of improving moving image color false contour of a moving image having a high moving speed. That is, according to the halftone display method proposed in Japanese Patent Application Laid-Open No. 10-133623, when the lighting pattern of a specific light-emitting block in each pixel changes between successive frames or fields, the frame of the lighting pattern Alternatively, the number of pixels in which a change that is equal to the change between fields is linearly continuous on the display screen is calculated. Further, the state of the lighting block in the frame or field of two pixels sandwiching the continuous pixels is detected, and the number of the continuous pixels, the state of the two pixels sandwiching the continuous pixels, and the change of the lighting pattern between frames or fields. A predetermined light-emitting block for luminance adjustment is selected according to the state. Then, the selected luminance adjusting light emitting block is added to or subtracted from the original signal of the continuous pixel.

FIG. 15 to FIG.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram for explaining an example of a conventional halftone display method (motion-compensated equalizing pulse method) proposed in JP-A-133623, and shows a case where a positive weighted equalizing pulse EPA is added. Here, the description of FIGS. 15 to 18 is based on the lighting sequence in which one frame shown in FIG. 1 described above is divided into 8-bit subframes SF0 to SF7 and gradation display is performed.

FIG. 15 shows a case where an image is moved from the right side to the left side at a speed of 3 pixels / frame, the vertical axis represents time t (frame time: 1F, 2F, 3F), and the horizontal axis represents the display panel. Are shown on the horizontal line (pixels A, B, C,..., P). In order to simplify the explanation, a single color display is considered here. In the case of a color display, each color (R, G, B) is considered.
What is necessary is just to add these. Further, the pixel area is assumed to be sufficiently small.

In FIG. 15, the vertical lines indicate the light emission state of each pixel. In the first frame (0 ≦ t <1F), pixels A to C
And P do not emit light, and pixels D to I have gradation levels 127 (1
(27 gradation levels), and the pixels J to O emit light at a gradation level 128 (128 gradation levels). Therefore, the pixels D to I emit light in the first half of this frame, and the pixels J to O emit light in the second half. Second frame (1F ≦ t <2
In F), since the pixels A to F emit light at the 127 gradation level and the pixels G to L emit light at the 128 gradation level, the pixels A to F emit light in the first half of the second frame and in the second half, G to L emit light. Hereinafter, it is assumed that a similar light emission pattern continues.

When the same pattern is displayed on all the horizontal lines in the panel, a vertically long belt pattern can be seen by the eyes. The six pixels in the left half of this belt are 127 gradation levels,
The six pixels in the right half emit light at the 128 gradation level, and the pattern has three pixels per frame (3 pixels /
(Frame) from the right to the left.
Although the position and temporal change of light emission are discrete, the eyes capture this as a smooth movement, and the center of the retina follows this belt pattern.

In FIG. 16 (a), the horizontal axis is the position coordinate x fixed on the retina. When the image moves from the right side to the left side, since the eyes follow the pattern, the pixels projected on the retina relatively move from the left side to the right side on the retina. Therefore, in FIG. 16 (a), it moves on a straight line descending to the right. In FIG. 16A, the left side is at 127 gradation levels, and the right side is at 128 gradation levels. Here, the pixel symbols A to P shown in the upper part of FIG. 16A are the positions at the time t = 0, and move from the left to the right with time.

FIG. 16 (b) shows a change in the spatial intensity of the light emission intensity recognized by the retina, and the light emission between time t = 0.5F and 1.5F (corresponding to the length of one frame). Is integrated. The same applies to FIG. 17 and FIG. As shown in FIG. 16B, a dark light emitting portion DP appears between the 127 and 128 gradation levels. In this time range, pixels G and H
Since the three pixels I and I shift from the 127-gradation level to the 128-gradation level between the first frame and the second frame, a period in which no light is emitted occurs for one frame (DD). This is a cause of the occurrence of the dark light emitting portion DP.

Therefore, it is necessary to apply an equalization pulse to three pixels (G, H, I). FIG. 17 (FIG. 17A)
This corresponds to the conventional halftone display method (equalized pulse method) proposed by the present inventors in Japanese Patent Application Laid-Open No. Hei 10-39828. Equalization pulse (positive weighted equalization pulse) E
The example which superimposed PA is shown. Here, the equalizing pulse E
As described with reference to FIG. 13, the size of the PA is calculated as, for example, a luminance level 63 (gray level 63).

As is clear from the comparison between FIG. 17B and FIG. 16B, as shown in FIG.
By adding A, the emission intensity recognized by the retina is shown in FIG.
It can be seen that it is improved as compared with 6 (b). In particular, 1
Since the amount that is too bright and the amount that is too dark are offset as compared with the luminance level (gradation level) of 27 or 128, when the display image is observed from a position sufficiently distant from the display panel, disturbance of the halftone is visually recognized. become unable.

However, when the panel is observed from a nearby position, the increase or decrease in the luminance is visually recognized. Further, as described with reference to the simulation results of FIGS. In the case where is larger than (in the case of 4 pixels / frame or 5 pixels / frame, etc.), the increase / decrease of the luminance becomes more conspicuous.

FIG. 18 shows an embodiment in which equalizing pulses are weighted by the halftone display method of the present invention.
This shows a case where a positive weighted equalization pulse EPA is added. As shown in FIG. 18A, in this embodiment, the equalization pulse EP of the gradation level 127 is applied to the pixel G.
A1 is added, an equalization pulse EPA2 having a gradation level 63 is added to the pixel H, and an equalization pulse EPA3 having a gradation level 0 is added to the pixel I (that is, the pixel I is equalized). No pulse is added).
The total amount of these equalization pulses (EPA1 + EPA2 + EP
A3 = 127 + 63 + 0 = 190) is set to be substantially equal to the total amount of the equalization pulses added in FIG. 17 (3 · EPA = 189).

As shown in FIG. 18B, it can be seen that the light emission intensity recognized by the retina is further improved as compared with FIG. 17B. In recent years, as the lighting sequence of the sub-frame, ⁰ 2 ratio of weights of luminance as shown in FIG. 1 described above, 2 ^1, 2 ^2, a plurality of light-emitting blocks and · · · 2 ^N-1 SF0, SF1 , SF2, ..., SF (N
-1), a plurality of light-emitting blocks having a large luminance weight (for example, the largest luminance weight) are provided, and one gradation display is combined with a plurality of subframes (light-emitting blocks). What is expressed by is becoming mainstream.

FIG. 19 is a diagram showing an example of a conventional lighting sequence of each sub-frame to which the present invention is applied. The above-described one gradation display can be expressed by a combination of a plurality of types of sub-frames. It is. As shown in FIG. 19, one frame (one field) has ten (N =
0-9) sub-frames (light-emitting blocks),
SF0, SF1,..., S
F9. Here, there are four light-emitting blocks having the largest luminance weights, SF6, SF7, SF8, and SF9, each of which has a 48 gradation level (gradation level 48: luminance level 48). In the following description, the light-emitting blocks SF6 and SF of these 48 gradation levels are used.
7, SF8 and SF9 are D1, D2, D3 and D4, respectively.
Also described.

In the lighting sequence of FIG. 19, the sum (64 + 128 = 192) of the gradation levels of the two light-emitting blocks (the two most significant bits) SF6 and SF7 in the lighting sequence of FIG. 4 light-emitting blocks SF6, SF7,
SF8 and SF9 (48 + 48 + 48 + 48 = 192). The light-emitting blocks SF0 to SF5 in the lighting sequence in FIG. 19 correspond to the light-emitting blocks SF0 to SF5 in the lighting sequence in FIG.

FIG. 20 is a diagram for explaining a problem in the lighting sequence shown in FIG. In FIG.
The horizontal axis indicates position coordinates x fixed on the retina, and the vertical axis indicates time t. Note that 0 and 1F on the vertical axis t indicate an image (0) in a frame (field) at a certain point in time and an image (1F) in the next frame. Reference numeral AA denotes a light-emitting block of 48 gradation levels (a light-emitting block having the largest luminance weight).
(D1, D2) to perform gradation display,
Further, reference numeral BB indicates a case where gradation display is performed using three (D1, D2, D3) light emitting blocks of 48 gradation levels. That is, 159-AA indicates a pixel that displays 159 gray levels using two light emitting blocks of 48 gray levels, and 160-BB uses three light emitting blocks of 48 gray levels. Pixel that displays 160 gray levels.

The halftone display method (motion-compensated equalizing pulse method) described with reference to FIGS. 15 to 18 compares the luminance of pixels between two consecutive frames, and determines On the other hand, a false contour is reduced by superimposing a weighted equalizing pulse. This conventional halftone display method is effective when the gradation increases or decreases smoothly, but is not effective when the gradation changes minutely.

That is, as shown in FIG. 20, there are 160 levels of one pixel in 159 levels, and
For example, when the image moves from the right side to the left side at a speed of 3 pixels / frame, the pixel e becomes 15
The pixel b changes from the 159 gray level to the 160 gray level. Here, 159 gradation levels are theoretically SF0 to SF5
And two 48 gradation levels (2 of SF6 to SF9)
One: For example, display by SF6, SF7 (D1, D2)) (1 + 2 + 4 + 8 + 16 + 32 + 48 + 48 = 159)
, But with SF0-SF4 and three 48
Tone level (three of SF6 to SF9: for example, SF
6, SF7, SF8 (D1, D2, D3)) (1 + 2 + 4 + 8 + 48 + 48 + 48 = 159). In other words, the 159 gradation levels use two or three light-emitting blocks (48 gradation levels) having the largest luminance weight, so that one gradation display is a combination of two subframes (the highest luminance level). Selection of the number of used light-emitting blocks having a large weight can be expressed in two ways). It should be noted that ten combinations are possible when considering combinations of the four light-emitting blocks D1 to D4 (SF6 to SF9) having the largest luminance weight.

On the other hand, the 160 gradation level is SF
1 to SF4 and three 48 gradation levels (SF6 to SF
9: SF6, SF7, SF8 (D
1, D2, D3)) (16 + 48 + 48 + 48)
= 160). That is, for the 160 gradation levels, three light emitting blocks (48 gradation levels) having the largest luminance weight must be used, and the combination of the light emitting blocks is limited to one.

However, in the prior art, for example, when displaying 159 gradation levels, the number of light-emitting blocks (48 gradation levels) having the largest weight is minimized (2
Logically, even if it can be expressed in two ways (the number of light-emitting blocks with the highest weight can be selected in two ways), it is effectively used. The idea itself did not exist.

That is, in the prior art, as shown in FIG. 20, one 48-gray-level light-emitting block (D) changes from OFF to ON for a pixel b.
A positive equalizing pulse is applied, and for the pixel e, one 48-gray-level light-emitting block (D) is turned ON from
In order to obtain F, a negative equalizing pulse is applied to display an intermediate gradation. However, if the gradation change is smooth, that is, if the pitch (number of pixels) at which the same lightest block having the highest weight changes is larger than the image movement distance between one frame, the number of pixels to which the equalizing pulse is applied is Since it is equal to the moving speed, correct motion compensation is possible. However, it becomes difficult to accurately detect the speed of a fine pattern as shown in FIG.
The moving speed is detected as 1 pixel / frame, and as a result, the disturbance is not sufficiently reduced.

According to the present invention, in view of the above-mentioned problems of the conventional halftone display technology, there is provided a lighting device with redundancy that can express one gradation display by combining a plurality of types of sub-frames (light-emitting blocks). It is an object of the present invention to provide a halftone display method and a display device capable of reducing the occurrence of a false contour of a moving image of a video (color false contour) by positively utilizing the redundancy when using a sequence.

[0064]

According to a first aspect of the present invention, there are provided a plurality of predetermined light emitting blocks in each frame or field for displaying an image,
This is a halftone display method for displaying one gradation level by a combination of a plurality of types of light-emitting blocks. In determining a light-emitting block used for gradation display of an arbitrary first pixel,
A halftone display method, wherein a light-emitting block used by the first pixel is selected in accordance with a predetermined procedure based on a usage state of the light-emitting block in a second pixel adjacent to the first pixel. Is provided.

According to the second aspect of the present invention, each frame or field has a plurality of predetermined light-emitting blocks for displaying an image, and one gray-scale level has a plurality of light-emitting blocks. A display device for displaying in a combination of: an image display unit; a driving unit for driving the image display unit; a control unit for controlling the driving unit; Light-emitting block selection and luminance adjustment light-emitting block insertion means for inserting a light-emitting block for light-emitting blocks, wherein the light-emitting block selection and luminance adjustment light-emitting block insertion means includes a light-emitting block used for gradation display of an arbitrary first pixel. In determining
A display device, wherein a light-emitting block used by the first pixel is selected in accordance with a predetermined procedure based on a usage state of the light-emitting block in a second pixel adjacent to the first pixel. Is provided.

According to the third embodiment of the present invention, each frame or field has a plurality of predetermined light-emitting blocks for displaying an image, and a plurality of light-emitting blocks each having one gradation level. A halftone display method which can be displayed by a combination of blocks, wherein in determining a light emitting block used for gradation display of an arbitrary first pixel, at least two or more reference pixels around the first pixel are used. A halftone display method is provided, wherein a light emitting block used by the first pixel is selected from a use state of the light emitting block by a predetermined procedure.

According to the fourth aspect of the present invention, each frame or field has a plurality of predetermined light-emitting blocks for displaying an image, and a plurality of light-emitting blocks for one gradation level. A display device capable of displaying a combination of blocks, an image display unit, a driving unit that drives the image display unit, a control unit that controls the driving unit,
A light-emitting block selection and luminance-adjustment light-emitting block insertion unit for selecting a light-emitting block and inserting a luminance-adjustment light-emitting block with respect to the original signal. In determining a light emitting block to be used for gradation display of one pixel, the light emitting block used by the first pixel is determined in advance based on the usage status of the light emitting block in at least two or more reference pixels surrounding the first pixel. A display device is provided, wherein the display device is selected according to a predetermined procedure.

According to the present invention, the selection of the light-emitting block is adjusted in advance so that the motion compensation equalizing pulse method can be effectively applied even to a fine pattern. The present invention is applied to a device using a lighting sequence having redundancy that can be expressed by a combination of light emitting blocks. That is, the present invention provides one frame (1
Field) is composed of a plurality of light-emitting blocks, and a halftone display method and display using a lighting sequence in which a plurality of light-emitting blocks with a large luminance weight (light-emitting blocks with the largest luminance weight) are provided among the light-emitting blocks. Applies to equipment.

Specifically, according to the present invention, for example, 10 frames (N = 0 to 9: S
F0 to SF9), and is applied to a halftone display method and a display device using a lighting sequence using four light emitting blocks (SF6 to SF9: halftone bit data b6 to b9) having the largest luminance weight. Is done. Note that each light-emitting block (SF
0 to SF9) are 1 (SF0), 2 (SF
1), 4 (SF2), 8 (SF3), 16 (SF4),
32 (SF5), 48 (SF6: D1), 48 (SF
7: D2), 48 (SF8: D3), 48 (SF9: D
4).

In response to the lighting sequence shown in FIG. 19, as shown in Table 1 below, pixel A (first pixel)
Alternatively, the gradation level L (luminance level: 0 to 255) of the pixel B (second pixel) is divided into nine groups.

[0071]

[Table 1]

As shown in Table 1 above, the gradation levels (L) 0 to 255 correspond to the group 1 (G = G) of L = 0 to 47.
1), group 2 of L = 48 to 63 (G = 2), L = 6
Group 3 of 4 to 95 (G = 3), Group 4 of L = 96 to 111 (G = 4), Group 5 of L = 112 to 143 (G = 5), Group 6 of L = 144 to 159 (G =
6), L = 160 to 191 group 7 (G = 7), L
= 192 to 207, group 8 (G = 8), and L
= 208 to 255 (9 = G = 9).

Here, for the groups 2, 4, 6, 8 (group number G = 2, 4, 6, 8), the gradation level 4
8 as halftone bit data b4 (SF4: gradation level 1
6) and the first expression expressed using halftone bit data b5 (SF5: gradation level 32) and one 48-light emission block D (halftone bit data b6 to b9 (SF6
To SF9 or one of D1 to D4).

In the present invention, the light-emitting block having the largest luminance weight (the light-emitting block D of the gradation level 48: D
For the selection (combination) of (1, D2, D3, D4), the following procedure is used. In the following description, an arbitrary pixel (first pixel) of interest is referred to as a pixel A, a pixel adjacent to the pixel A (a second pixel) is referred to as a pixel B, and a group number (G ) Are GA and GB.

First, the group number GA of the pixel A is determined according to Table 1 described above. Next, in order to determine the number of light-emitting blocks D used by the pixel A and having the largest luminance weight (the light-emitting blocks D1 to D4 of the gradation level 48 having the largest luminance weight), the group number GA and the left A comparison is made with the group number GB of the adjacent pixel B. And pixel A
And the group number G of the pixel B on the left
B according to the comparison result with the light emitting block D of the pixel A
The number (arrangement) of selections (the light-emitting blocks of the gradation level 48 having the largest luminance weight) is determined.

Specifically, for example, when both pixel A and pixel B belong to group 4 (GA = GB = 4),
When the pixel B on the left is represented by the first expression in Table 1 (when one light-emitting block D is used), the pixel A also uses the first expression using one light-emitting block D. To display the gradation level. The group number GB of the pixel B on the left is the group number GA of the pixel A.
Is smaller than (GB <GA), specifically, for example,
When the group number of the pixel B on the left is 3 (GB = 3) and the group number of the pixel A is 4 (GA = 4), the pixel A
The display of the gradation level is performed using the number of light-emitting blocks D (one light-emitting block) determined by the first expression in Table 1.

Then, the group number G of the pixel B on the left is
B is larger than the group number GA of the pixel A (GB
> GA), for example, the group number of the pixel B on the left is 5
(GB = 5) and the group number of pixel A is 4 (GA = 4)
At this time, the pixel A displays the gradation level using the number of light-emitting blocks D (two light-emitting blocks) determined by the second expression in Table 1.

The above processing can be summarized as follows.
Is determined by using the number of light-emitting blocks D having the largest luminance weight defined by the following equations. In the case of GB <GA... First expression In the case of GB = GA... The same expression as the pixel B adjacent to the left. In the case of GB> GA... The second expression. The pixel B on the left does not actually exist, but it is assumed that the group number is 0 and that the number of light emitting blocks D to be used is 0. For example, if the pixel A (first pixel) is the top left pixel, the pixel A is compared with the pixel at the same position in the previous frame. You may be comprised so that it may compare with. Pixel B
When the (second pixel) does not exist on the display screen, the group number of the pixel B is not limited to 0, and can be assumed to be an arbitrary number (for example, 9). Further, the light-emitting block (gradation level) D is not limited to the one with the largest luminance weight, and may be, for example, the one with the second largest luminance weight in the light-emitting sequence. In this case, however, there are a plurality of light-emitting blocks having the second largest luminance weight, and a plurality of expressions need to be present to display one gradation level.

Next, four light-emitting blocks D1 are used as light-emitting blocks D of the gradation level 48 having the largest luminance weight.
Which of D4 to use is determined according to Table 2 below.
Here, in Table 2, “0” indicates no light, and
“1” indicates lighting. Therefore, for example, the arrangement (setting) of the four light emitting blocks D1 to D4 is (D1, D
(2, D3, D4) = (0101) represents the light-emitting block D of the gradation level 48 having the largest luminance weight.
Is turned on when the light-emitting blocks D2 and D4 are turned on and the light-emitting blocks D1 and D3 are turned off.

[0080]

[Table 2]

As shown in Table 2 above, for example, when the arrangement of the light emitting block D for displaying the gradation level of the pixel B adjacent to the pixel A on the left side is (0000), the pixel A If the number of the light-emitting blocks D used to display the gradation level of is two, the arrangement of the light-emitting blocks D in the pixel A is (D1, D2, D3, D
4) = (1100). Further, for example, when the arrangement of the light emitting blocks D for displaying the gradation level of the pixel B on the left is (0111), the number of the light emitting blocks D used for displaying the gradation level of the pixel A is three. If there are two, the arrangement of the light-emitting blocks D in the pixel A is (D1, D2, D3, D4) = (0111). Further, for example, when the arrangement of the light emitting blocks D for displaying the gradation level of the pixel B on the left is (1011), the number of the light emitting blocks D used for displaying the gradation level of the pixel A is two. , The arrangement of the light emitting block D in the pixel A is (D1, D2, D3, D4)
= (0011). That is, the arrangement of the light-emitting blocks D used to display the gradation level of the pixel A is determined so that the arrangement of the light-emitting blocks D for displaying the gradation level of the pixel B on the left does not change as much as possible. Has become.

Here, for example, when the arrangement of the light-emitting blocks D of the pixel B on the left is (1011), and when the number of the light-emitting blocks D used for displaying the gradation level of the pixel A is two, (D1, D2, D3, D4) = (1001) or (D1, D2, D3, D4) = (D1, D2, D3, D4) = (1001) without setting the arrangement of the light emitting block D in the pixel A to (D1, D2, D3, D4) = (0011). The light emitting block D that changes as (1010) may be determined to be a minimum (one).

By the above procedure, the light emission patterns of all the pixels on the display screen are determined. As described above, according to the present invention, when using a lighting sequence with redundancy that can express one gradation display by combining a plurality of light-emitting blocks, the redundancy is actively utilized. As a result, it is possible to reduce the occurrence of false contours of moving images (color false contours) of a video image.
The quality of the displayed image can be improved by effectively applying the motion compensation equalization pulse method proposed in Japanese Patent No. 3623. [Remarks] 1. Having a plurality of predetermined light-emitting blocks in each frame or field to display an image,
A halftone display method capable of displaying one grayscale level by a combination of a plurality of types of the light emitting blocks, wherein a first light emitting block used for grayscale display of an arbitrary first pixel is determined. A halftone display method, wherein a light-emitting block used by the first pixel is selected in accordance with a predetermined procedure based on a usage state of the light-emitting block in a second pixel close to the pixel.

2. 2. The halftone display method according to item 1, wherein the second pixel generates the same color as the first pixel, and is left, right, above, or
A halftone display method, characterized in that the pixel is the closest pixel in the downward direction. 3. Item 2. The halftone display method according to Item 2, wherein when the second pixel is not present on the display screen, the display gradation of the second pixel is set to an arbitrary constant level. Key display method.

4. 4. The halftone display method according to any one of items 1 to 3, wherein the plurality of light emitting blocks predetermined in each of the frames or fields include a plurality of light emitting blocks having the largest luminance weight. A halftone display method characterized by being configured with redundancy. 5. In the halftone display method according to item 4, the use of the light-emitting block having the largest luminance weight in the first pixel is determined based on the use state of the light-emitting block having the largest luminance weight in the second pixel. And a halftone display method.

6. In the halftone display method according to item 5, the number of light-emitting blocks having the highest luminance weight in the first pixel is determined from the number of light-emitting blocks having the highest luminance weight in the second pixel. A halftone display method characterized in that: 7. In the halftone display method according to item 6, all the gradation levels are grouped according to the usable number of the light-emitting blocks having the largest luminance weight, and the gradation levels are displayed by the first and second pixels. A group number is given to the group according to the grouped gradation levels,
And comparing the group number given to the second pixel, and selecting and displaying one of the plurality of combinations of the light emitting blocks for the gray level of the first pixel. Characteristic halftone display method.

8. 7. In the halftone display method according to item 7, the display gradation of each pixel is based on the first expression in which the number of light-emitting blocks with the highest luminance weight is small and the use of the light-emitting blocks with the highest luminance weight. The number of light-emitting blocks having the largest luminance weight in the first pixel is represented by the group number GA of the first pixel and the number of light-emitting blocks used in the first pixel. A halftone display method, wherein the group number GB of the second pixel is compared and determined by the following equation.

8. When GB <GA: First expression When GB = GA: Expression same as that of second pixel When GB> GA: Second expression Item 6. In the halftone display method according to Item 6, in all of the light-emitting blocks having the largest luminance weight, the selection condition of the light-emitting block having the largest luminance weight used by the first pixel is set to the second pixel. A halftone display method characterized in that it is determined according to the use condition of the light-emitting block having the largest luminance weight used by the device.

10. 10. The halftone display method according to any one of items 6 to 9, wherein a use state of one of the light-emitting blocks having the largest luminance in the first pixel changes between consecutive frames or fields. At this time, the number of pixels that show a change equal to the change in the light-emitting block having the largest luminance weight in the first pixel is detected on the display screen in a linearly continuous manner. A predetermined luminance adjustment light-emitting block is selected in accordance with a change in the light-emitting block having the largest luminance weight in the first pixel, and the selected luminance-adjustment light-emitting block is used as the source of the continuous pixel. A halftone display method characterized by giving to a signal.

11. In the halftone display method according to item 10, the pixels for giving the luminance adjustment light-emitting blocks to the original signal are arranged on the opposite side of the detected number of consecutive pixels and the second pixels. A halftone display method characterized by further comprising one pixel. 12. The halftone display method according to any one of items 6 to 9, wherein
When the use state of any of the light-emitting blocks having the highest luminance weight in the first pixel changes, a pixel showing a change equal to the change of the light-emitting block having the highest luminance weight in the first pixel is displayed. The number of pixels that are linearly continuous on the screen is detected in the horizontal direction and the vertical direction, and the smaller one of the detected number of consecutive pixels in the horizontal and vertical directions, and A predetermined luminance adjustment light-emitting block is selected according to a change in a light-emitting block having a large luminance weight, and the selected luminance adjustment light-emitting block is provided to an original signal of the continuous pixel. A halftone display method characterized by the following.

13. In the halftone display method according to item 12, a pixel that gives the luminance adjustment light-emitting block to an original signal is a pixel having a smaller one of the detected number of consecutive pixels in the horizontal and vertical directions. And a further pixel on the opposite side of the second pixel. 14. In the halftone display method according to any one of Items 10 to 13, the detection of the light-emitting block having the largest luminance weight whose use state changes between consecutive frames or fields is detected by the luminance-maximum luminance block. A halftone display method characterized in that the light-emitting blocks located on the side of the light-emitting block with the larger weight and the one with the smaller light-weight are sequentially executed.

15. In the halftone display method according to any one of Items 4 to 14, the number of the plurality of light-emitting blocks is set to 10, and the weight of the luminance of each of the light-emitting blocks is set to a gradation level of 1, 2,4,8,16,32,48,4
A halftone display method characterized in that the display is set to 8, 48, 48. 16. Having a plurality of predetermined light-emitting blocks in each frame or field for displaying an image,
A display device capable of displaying one gradation level by a combination of a plurality of types of light-emitting blocks, comprising: an image display unit;
A driving unit for driving the image display unit, a control unit for controlling the driving unit, a light-emitting block selection for inserting a light-emitting block and inserting a luminance-adjusting light-emitting block with respect to an original signal, and inserting a light-emitting block for luminance adjustment. With means,
The light-emitting block selection and brightness-adjusting light-emitting block inserting means determines a light-emitting block to be used for gradation display of an arbitrary first pixel by determining a light-emitting block in a second pixel adjacent to the first pixel. A display device, wherein a light-emitting block used by the first pixel is selected in accordance with a predetermined procedure from a use situation.

17. The display device according to item 16, wherein the second pixel generates the same color as the first pixel, and is left, right, above, or A display device, which is a pixel that is closest in the downward direction. 18. The display device according to item 17, wherein when the second pixel does not exist on the display screen, the display gradation of the second pixel is set to a constant level of an arbitrary value. apparatus.

19. The display device according to any one of Items 16 to 18, wherein the plurality of predetermined light-emitting blocks in each frame or field include a plurality of light-emitting blocks having the largest luminance weight. A display device characterized in that it is configured to have redundancy so as to include the same. 20. The display device according to item 19, wherein the use of the light-emitting block having the largest luminance weight in the first pixel is determined based on the use state of the light-emitting block having the largest luminance weight in the second pixel. A display device, comprising:

21. In the display device according to item 19, the number of light-emitting blocks having the highest luminance weight in the first pixel is determined by the number of light-emitting blocks having the highest luminance weight in the second pixel. A display device characterized in that it is determined from the following. 22. In the display device according to item 21, the light emitting block selection and luminance adjusting light emitting block inserting means includes:
A group number is assigned in accordance with the grayscale level displayed by the first and second pixels according to the grayscale level obtained by grouping all the grayscale levels according to the usable number of the light-emitting blocks having the largest luminance weight. The given group number assigning means is compared with the group numbers given to the first and second pixels, and the gradation level of the first pixel is set to one of the combinations of the plurality of light emitting blocks. A display device comprising: a light-emitting block combination selecting means for selecting.

23. In the display device according to item 22, the display gradation of each pixel is represented by the first expression in which the number of the light-emitting blocks having the largest luminance weight is small and the light emission having the largest luminance weight. The number of used blocks can be expressed in two ways of the second expression, and the number of used light-emitting blocks having the largest luminance weight in the first pixel is represented by the group of the first pixel. A display device, wherein a number GA is compared with a group number GB of the second pixel to be determined by the following equation.

24. In the display device according to item 21, when GB <GA: the first expression When GB = GA: the same expression as the second pixel When GB> GA: the second expression In all of the light-emitting blocks having the highest luminance weight, the selection condition of the plurality of light-emitting blocks having the highest luminance weight used by the first pixel is set to the highest luminance weight used by the second pixel. A display device characterized in that it is determined according to the use condition of a light emitting block having a large size.

25. In the display device according to any one of items 21 to 24, the light-emitting block selecting and luminance-adjusting light-emitting block inserting means may include a light-emitting block selecting unit and a luminance-adjusting light-emitting block inserting unit, which are connected to each other in the first pixel between consecutive frames or fields. A light-emitting block change detecting means for detecting a change in the use state of any of the light-emitting blocks having the largest luminance weight,
A continuous pixel number detecting means for detecting the number of linearly continuous pixels on the display screen that exhibit a change equal to the change in the light-emitting block having the largest luminance weight in the first pixel; A luminance adjusting light-emitting block selecting means for selecting a predetermined luminance-adjusting light-emitting block according to the number and a change in the light-emitting block having the largest luminance weight in the first pixel; A display device comprising: a luminance-adjusting light-emitting block providing unit that applies an adjusting light-emitting block to the original signals of the continuous pixels.

26. In the display device according to item 25, the pixels that provide the luminance-adjustment light-emitting blocks to the original signal include the detected consecutive number of pixels and the pixels on the opposite side of the second pixels. A display device comprising one pixel. 27. In the display device according to any one of Items 21 to 24, the light-emitting block selection and luminance-adjustment light-emitting block inserting means includes a light-emitting block selecting unit and a luminance-adjusting light-emitting block inserting unit, the light-emitting block being selected between the consecutive frames or fields. A light-emitting block change detecting means for detecting a change in the use state of one of the light-emitting blocks having the larger weight, and a pixel showing a change equal to the change of the light-emitting block having the highest luminance in the first pixel is displayed on the display screen. A continuous pixel number detecting means for detecting a linearly continuous number in the horizontal direction and the vertical direction, a smaller pixel number of the detected continuous horizontal and vertical pixels, and Luminance adjustment light emission for selecting a predetermined luminance adjustment light emission block according to a change in a light emission block having the largest luminance weight in one pixel A display device comprising: a block selecting unit; and a luminance adjusting light emitting block providing unit that applies the selected luminance adjusting light emitting block to the original signals of the continuous pixels.

28. In the display device according to item 27, a pixel that gives the luminance-adjusting light-emitting block to an original signal includes a smaller one of the detected number of pixels in the continuous horizontal and vertical directions, and And a further pixel on the opposite side of the second pixel. 29. In the display device according to any one of items 25 to 28, the light-emitting block change detecting unit detects the light-emitting block having the largest luminance weight whose use state changes between the consecutive frames or fields. The light-emitting blocks located on the side of the light-emitting block having the highest luminance weight having the lowest luminance weight are sequentially executed.

30. The display device according to any one of Items 19 to 29, wherein the number of the plurality of light-emitting blocks is 10, and the weight of the luminance of each of the light-emitting blocks is one of gradation levels 1, 2, and 2, respectively. 4, 8, 16, 32, 48, 48,
48. A display device, wherein the display device is set to 48. 31. Having a plurality of predetermined light-emitting blocks in each frame or field for displaying an image,
A halftone display method capable of displaying one grayscale level by a combination of a plurality of types of the light emitting blocks, wherein a first light emitting block used for grayscale display of an arbitrary first pixel is determined. A halftone display method, wherein a light-emitting block used by the first pixel is selected in accordance with a predetermined procedure based on the usage state of the light-emitting block in at least two or more reference pixels around the pixel.

32. The halftone display method according to item 31, wherein the reference pixel is a pixel directly adjacent to the first pixel. 33. The halftone display method according to item 31, wherein the reference pixel is a pixel directly adjacent to the first pixel or adjacent via another pixel. Method.

34. In the halftone display method according to any one of Items 32 and 33, the reference pixels are subjected to a majority decision, and the first pixels are determined based on the usage status of the light-emitting blocks exceeding a majority of the reference pixels. A halftone display method, wherein a light emitting block used by a pixel is selected. 35. In the halftone display method according to item 34, when the number of the reference pixels is even and the number of the reference pixels in the different light-emitting blocks is the same, the light-emitting block used by the first pixel is not changed. A halftone display method characterized by maintaining.

36. In the halftone display method according to any one of the items 32 and 33, the reference pixel is weighted by a positional relationship with the first pixel, and the reference pixel is weighted. A halftone display method, wherein a light-emitting block used by the first pixel is selected based on a use state of a light-emitting block of a reference pixel.

37. In the halftone display method according to item 36, if the weighted reference pixels of different light-emitting blocks are the same, the light-emitting block used by the first pixel is kept unchanged. A halftone display method characterized in that: 38. Each frame or field has a plurality of predetermined light-emitting blocks for displaying an image,
A display device capable of displaying one gradation level by a combination of a plurality of types of light-emitting blocks, comprising: an image display unit;
A driving unit for driving the image display unit, a control unit for controlling the driving unit, a light-emitting block selection for inserting a light-emitting block and inserting a luminance-adjusting light-emitting block with respect to an original signal, and inserting a light-emitting block for luminance adjustment. With means,
The light emitting block selection and brightness adjusting light emitting block inserting means determines a light emitting block to be used for gradation display of an arbitrary first pixel by emitting light in at least two or more reference pixels around the first pixel. A display device, wherein a light-emitting block used by the first pixel is selected in accordance with a predetermined procedure from a use state of the block.

39. The display device according to item 38, wherein the reference pixel is a pixel directly adjacent to the first pixel. 40. The display device according to item 38, wherein the reference pixel is a pixel directly adjacent to the first pixel or adjacent via another pixel.

41. In the display device according to any one of Items 39 and 40, the reference pixel is subjected to a majority decision, and the first pixel is determined based on a usage state of a light-emitting block exceeding a majority of the reference pixels. A display device, wherein a light-emitting block to be used is selected. 42. In the display device according to item 41, when the number of the reference pixels is even and the number of the reference pixels in the different light-emitting blocks is the same, the light-emitting block used by the first pixel is maintained without being changed. A display device characterized in that:

43. In the display device according to any one of items 39 and 40, the reference pixel includes the first pixel.
A weighting is given by the positional relationship with the pixel, and the light emitting block used by the first pixel is selected from the weighted use status of the light emitting block of the reference pixel. apparatus. 44. The display device according to item 43, wherein, when the weighted reference pixels of different light-emitting blocks are the same, the light-emitting block used by the first pixel is maintained unchanged. Display device.

45. The display device according to any one of items 38 to 44, characterized in that the display device includes lighting pattern setting means for setting the entire display screen to a predetermined lighting pattern. Display device. 46. The display device according to item 45, wherein the lighting pattern setting means sets a light emitting state in which a light emitting block having the largest luminance level weight is used as much as possible for each pixel of the entire display screen. Display device.

[0110]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a halftone display method and a display device according to the present invention. First, an example of a display device for realizing the halftone display method according to the present invention will be described with reference to FIG.

FIG. 21 is a block diagram showing an example of a display device when the above-described halftone display method according to the present invention is carried out. In FIG. 21, reference numeral 100 denotes a display device, and 200 denotes a light-emitting block selecting and luminance-adjusting light-emitting block inserting unit. Here, reference numeral 210
Denotes an original signal (display data), and 220 denotes a signal after the luminance adjustment light emitting block is inserted.

As shown in FIG. 21, the display device 100
Are an image display unit (display panel) 102, an X decoder 131 for driving the image display unit 102, an X driver 132, a Y decoder 141, and a Y driver 14.
2, and the X driver 132 and the Y driver 142
Is provided with a control unit 5 for controlling the driving of the. The image display unit 102 has n lines in the vertical direction and m pixels in the horizontal direction of each line (vertical, horizontal) =
The pixel configuration is (n, m).

Here, as shown in FIG. 19, for example, one frame of the image is displayed on the image display unit 102 while changing the gradation by a plurality of sub-frames (light-emitting blocks).
, And the plurality of sub-frames are each composed of, for example, an address period and a sustain discharge period. As a display device to which the present invention is applied, in addition to a gas discharge panel such as a plasma display, various display devices that perform halftone display by a frame or in-field time division method, for example, a DMD (Digital Mimic)
Of course, it can also be applied to a cromirror device) or an EL panel.

That is, the display device 100 shown in FIG.
Can basically use any panel as long as it has a structure that performs gradation display using subframes. The present invention applies display data (original signal 210) to display data (original signal 210). What is necessary is just to supply the light to the display device 100 through the light emitting block selection and luminance adjusting light emitting block inserting means 200. Here, as described later, the light-emitting block selecting and luminance adjusting light-emitting block inserting means 200 selects, for example, a plurality of light-emitting blocks D (D1 to D4) having the largest luminance weight in an appropriate number, and According to the presence or absence of a signal change between frames (or fields) of the signal 210, a light emission block (equalization pulse: sub-frame) for luminance adjustment is added to the original signal, or a signal 220 obtained by subtraction is output. Has become.

The halftone display method and display device of the present invention are based on the lighting sequence of a sub-frame having a plurality of light-emitting blocks having a large luminance weight (for example, the largest luminance weight) as shown in FIG. It is assumed that a lighting sequence having redundancy that can express one gradation display by a combination of a plurality of types of sub-frames (light-emitting blocks) is provided. And the present invention
For example, while keeping the total amount of equalization pulses applied to the discharge cells of the plasma display panel (PDP) constant, each of the components is controlled so that the spatial change of the emission intensity pattern visually recognized with respect to the movement of the display image becomes uniform. When weighting the pulsing pulse, the redundancy of the lighting sequence is positively utilized as a preprocessing, and the generation of false contours (color false contours) of the moving image of the video is controlled by controlling the combination of the light emitting blocks. It is intended to further improve the display image.

In the present invention, it is determined which of the two light emission patterns (first expression and second expression) in Table 1 is selected according to the light emission pattern of the pixel adjacent to the left, and The motion compensation equalizing pulse can be added accurately. FIG. 22 is a diagram for explaining the principle of the halftone display method according to the present invention, and corresponds to FIG. 20 described above.

In FIG. 22, the horizontal axis represents the position coordinate x fixed on the retina, and the vertical axis represents the time t.
Note that 0 and 1F on the vertical axis t indicate an image (0) in a frame (field) at a certain point in time and an image (1F) in the next frame. Reference numeral AA denotes two light-emitting blocks (light-emitting blocks having the largest luminance weight) of 48 gradation levels (for example, D1 and D
2) shows a case where gradation display is performed by using, and reference numeral BB indicates a case where gradation display is performed using three (for example, D1, D2, and D3) light emitting blocks of 48 gradation levels. ing. That is, 159-AA indicates a pixel that displays 159 grayscale levels using two 48 grayscale light emitting blocks, and 159-BB indicates 159 that uses three 48 grayscale level light emitting blocks. A pixel that displays a gray scale level is shown, and 160-BB indicates a pixel that displays a 160 gray scale level using three light emitting blocks of 48 gray scale levels.

As shown in FIG. 22, in an image of a frame at a certain time point (time 0), pixels a, b, c, and d use two light-emitting blocks D (light-emitting blocks having the largest luminance weight) ( Illuminated) to perform gradation display, and the pixel e performs gradation display using three light-emitting blocks D. At this time, the pixels after the pixel f also have the light emitting blocks D according to the number of the light emitting blocks D in the pixel on the left.
Is used to perform gradation display. That is, in Table 1, the group numbers Gd, Ge, and Gf of the pixels d, e, and f are Gd = 6, Ge = 7, and Gf = 6. Become. Thus, pixel e will be represented by the first representation (160-BB) and pixel f will be represented by the second representation (159-BB). Note that the pixels a, b, c, and d each have a group number Ga, Gb, Gc, Gd of 6, so that G0 (0) <Ga, Ga = Gb, Gb = Gc, G
c = Gd, and the pixel a is in the first expression (159-AA)
Thus, the pixels b, c, and d are represented by the same expression (first expression: 159-AA) as the pixel on the left (a, b, c). Here, the pixel (0) on the left side of the pixel (left end pixel) a does not actually exist, but it is assumed that the group number G0 of the pixel 0 is 0 as described above.

Further, in the image of the next frame (1F), when the image moves from the right side to the left side at a speed of 3 pixels / frame, the three pixels b, c, and d all have the number of light emitting blocks D. Increase by one. That is, in Table 1, the group numbers Ga, Gb, Gc of the pixels a, b, c
Are Ga = 6, Gb = 7, Gc = 6, and when comparing the group numbers, G0 (0) <Ga, Ga <Gb,
Gb> Gc. Therefore, pixel a is represented by the first expression (15
9-AA), and the pixel b is also represented by the first expression (160
-BB) and pixel c will be represented by the second representation (159-BB). Note that pixels c, d, e, and f are group numbers Gc, G, respectively.
Since d, Ge, and Gf are 6, Gc = Gd and Gd = G
e, Ge = Gf, and the pixels d, e, f have the same expression as the pixel (c, d, e) on the left (second expression: 159-B
B). Therefore, the moving speed of the image can be correctly detected as 3 pixels / frame from the number of consecutive pixels having the same change in the number of light emitting blocks D used between two consecutive frames. For one pixel, for example,
By applying the motion-compensated equalizing pulse method proposed in JP-B-133623, it is possible to reduce the false contour of a moving image and improve the quality of a displayed image.

Next, an equalization pulse (motion compensation equalization pulse)
How to add is explained. That is, according to the present invention, the above-described processing is performed to perform the gradation display of each pixel. Further, for the plurality (four) of the light-emitting blocks D (D1 to D4) having the largest luminance weight, the following is performed. Then, a look-up table is created and motion compensation using an equalizing pulse is performed.

FIG. 23 is a flowchart schematically showing a halftone display method according to the present invention.
1 to D4) show how to add an equalizing pulse when there is a variation. As shown in the flowchart of FIG. 23, in the insertion process (addition / subtraction process) of the motion compensation equalization pulse, first, in step ST91, the change of the D block of the luminance signal between two consecutive frames (fields), that is, A change in the light-emitting blocks D (D1 to D4) having the largest luminance weight used to display the gradation level of a certain pixel between two consecutive frames is examined.
Proceed to step ST92. In step ST92, the first
It is determined whether or not the light-emitting block D1 changes. If it is determined that the light-emitting block D1 changes, step ST93 is performed.
The process proceeds to step ST94 if it is determined that the light-emitting block D1 does not change. In step ST94, similarly to step ST92, it is determined whether or not the second light-emitting block D2 changes. If it is determined that the light-emitting block D2 changes, the process proceeds to step ST95, where the light-emitting block D2 is changed.
If it is determined that does not change, the process proceeds to step ST96.

Further, in step ST96, similarly to steps ST92 and ST94, it is determined whether or not the third light-emitting block D3 changes. If it is determined that the light-emitting block D3 changes, the process proceeds to step ST97. If it is determined that D3 does not change, step ST9 is performed.
Proceed to 8. In step ST98, similarly to step ST96, it is determined whether or not the fourth light-emitting block D4 changes. If it is determined that the light-emitting block D4 has changed, the process proceeds to step ST99, and it is determined that the light-emitting block D4 does not change. Then, the process returns to step ST91, and performs the processes of steps ST91 to ST99 on the next pixel.

On the other hand, in step ST93, two consecutive
An equalizing pulse insertion process (addition / subtraction process) is performed on the first light emitting block D1 that changes between two frames. In step ST95, an equalizing pulse inserting process is performed on the second light emitting block D2. In step ST97, Third
In step ST99, an equalizing pulse is inserted into the fourth light emitting block D4, and the process returns to step ST91, and the process returns to step ST91. The processing of steps ST91 to ST99 is performed.

Here, an equalizing pulse (motion compensation equalizing pulse) inserted when each of the light emitting blocks D1 to D4 changes.
Is obtained from the following Tables 3 to 6 (look-up tables).

[0125]

[Table 3]

[0126]

[Table 4]

[0127]

[Table 5]

[0128]

[Table 6]

In Tables 3 to 6, "0" indicates that the light-emitting blocks D (D1 to D4) are turned off.
Indicates lighting of the light-emitting block D. Therefore, D1 being 0 → 1 indicates that the first light-emitting block D1 in the light-emitting block D having the largest luminance weight changes from off to on, and at this time, the number of pixels having the same change continues. Accordingly, a luminance adjustment light-emitting block (equalization pulse) is inserted (addition / subtraction processing). Further, when D2 is 1 → 0, it indicates that the second light-emitting block D2 in the light-emitting block D having the largest luminance weight changes from on to off, and at this time, the number of pixels having the same change continues. Accordingly, a luminance adjusting light-emitting block is inserted.

Specifically, as shown in Table 3, for example, when the first light-emitting block D1 changes from unlit to lit between two consecutive frames (fields) (D1
Is 0 → 1), and when three pixels having the same change continue, an equalizing pulse having a gradation level of 29, 0, 0 is given (inserted) to each of these pixels. Further, as shown in Table 4, for example, when the third light-emitting block D3 changes from off to on during two consecutive frames (D3
Is 0 → 1), and when five pixels having the same change continue, the gradation levels 47, 47, 3
1,13,0 equalizing pulses are given.

As shown in Table 5, for example, when the second light-emitting block D2 changes from lighting to non-lighting (D2 is 1 → 0) between two consecutive frames, pixels having the same change are detected. When four pixels are continuous, an equalizing pulse having a gradation level of -47, -27, 0, 0 is applied to each of these pixels. Further, as shown in Table 6, for example, when the fourth light-emitting block D4 changes from lighting to non-lighting (D4 is 1 → 0) between two consecutive frames, two pixels having the same change are consecutive. In this case, equalizing pulses of gradation levels -47 and -25 are applied to these pixels.

FIG. 24 is a flow chart for explaining an example of a halftone display method according to the present invention, and shows how to apply a motion compensation equalizing pulse to a movement in an arbitrary direction. Here, step ST191 in FIG.
Steps ST199 to ST199 basically correspond to steps ST91 to ST99 in FIG. 23 described above. As shown in the flowchart of FIG. 24, in the motion compensation equalization pulse insertion process (addition / subtraction process), first, in step ST191, the nth frame (field) and the (n + 1) th frame (field) are applied to all the pixels in the panel. ) Is checked for changes in the light-emitting blocks D (D1 to D4) having the largest luminance weights, and areas that change and areas that do not change are selected, and the process proceeds to step ST192. In step ST192, the first of the light-emitting blocks D having the largest luminance weight is set.
It is determined whether or not the light emitting block D1 changes. If it is determined that the light emitting block D1 changes, step ST19 is performed.
Then, if it is determined that the light-emitting block D1 does not change, the process proceeds to step ST194.

In step ST194, step ST1 is executed.
Similarly to 92, it is determined whether or not the second light-emitting block D2 changes. If it is determined that the light-emitting block D2 has changed, the process proceeds to step ST195. If it is determined that the light-emitting block D2 does not change, the process proceeds to step ST196. move on. Further, in step ST196, similarly to steps ST192 and ST194, it is determined whether or not the third light-emitting block D3 changes. If it is determined that the light-emitting block D3 changes, the process proceeds to step ST197, where the light-emitting block D3 is changed.
If it is determined that No. 3 does not change, the process proceeds to step ST198. In step ST198, similarly to step ST196, it is determined whether or not the fourth light-emitting block D4 changes. If it is determined that the light-emitting block D4 has changed, the process proceeds to step ST199, and it is determined that the light-emitting block D4 does not change. Then, the process returns to step ST191, and performs the processes of steps ST191 to ST199 on the next pixel.

On the other hand, in step ST193, an equalizing pulse insertion process (addition / subtraction process) is performed on the first light emitting block D1 that changes between two consecutive frames. First, the first light emitting block D1 changes. In the region, the number of pixels that continuously change in the direction of D1 from 0 → 1 (light-off to light-on) or 1 → 0 (light-on to light-off) is counted. Further, in the area where the first light-emitting block D1 changes, the number of pixels in which D1 changes 0 → 1 or 1 → 0 in the vertical direction is counted. Then, of the number of pixels in which the change of D1 from 0 → 1 or 1 → 0 is continuous in the horizontal direction and the vertical direction, the smaller one (horizontal or vertical) of the number of pixels in which the change of D1 is continuous is selected. Then, a motion compensation equalization pulse for the first light-emitting block D1 is given (inserted) according to Tables 3 to 6 described above or Table 7 described later.

In step ST195, the same processing as in step ST193 is performed on the second light emitting block D2, and a motion compensation equalizing pulse for the second light emitting block D2 is given. Similarly, in step ST197, a motion compensation equalizing pulse for the third light emitting block D3 is provided, and in step ST199, a motion compensation equalizing pulse for the fourth light emitting block D4 is provided.

As described above, in this embodiment, when the image moves in an arbitrary direction, the pixels having the same change in the light-emitting blocks D (D1 to D4) having the largest luminance weight are determined in the horizontal and vertical directions. , And the smaller continuous number (horizontal direction or vertical direction) is selected as the moving direction of the image. Further, the magnitude of the motion compensation equalization pulse is selected in the moving direction of the selected image, and is superimposed on the original signal.

[0137]

[Table 7]

Tables 3 to 6 described above show examples of equalizing pulses to be inserted (added or subtracted) when each of the light-emitting blocks D1 to D4 is changed. 6 shows another example for the second embodiment. That is, Tables 3 to
In Table 6, the equalization pulse is given to v pixels for the moving speed v [pixel / frame] of the image. However, in the example shown in Table 7, an equalizing pulse is given (inserted) to v + 1 pixels, which is one more pixel to the right.

Specifically, as shown in Table 7, for example, when the first light-emitting block D1 changes from unlit to lit between two consecutive frames (fields) (D1
Is 0 → 1), and if there is one pixel that changes equally,
An equalization pulse having a gradation level of 12 or -4 is applied to a total of two pixels including the pixel and the pixel on the right. Also, for example, when the third light-emitting block D3 changes from off to on between two consecutive frames (D3 is changed from 0 to 1),
When there are two pixels that change equally, equalizing pulses of gradation levels 47, 9, and -4 are given to the two pixels that change and the three pixels on the right. Furthermore, for example, the fourth frame between two consecutive frames
When the light-emitting block D3 changes from on to off (D
4 is 1 → 0), and when there are three pixels that change equally, the gradation levels of −14, −48,
Apply -50,2 equalization pulses.

Tables 3 to 6 and 7 show examples of the motion compensation equalizing pulse insertion processing, respectively, and the present invention is not limited to these. FIG.
26 is a flowchart showing the operation of an example of the halftone display method according to the present invention. As shown in FIG. 25, when the halftone display processing starts, step ST101
In, a pixel at coordinates (x, y) = (0, 0) is set, and the process proceeds to step ST102. Here, the display image (image display unit 102) has n lines in the vertical direction and m lines in the horizontal direction.
The row is composed of pixels of (vertical, horizontal) = (0, 0) to (n, m). Note that pixels (0, 0) to (0, m) at the left end of the display image have a gray scale level 0
The processing is performed on the assumption that the pixel of the above exists.

[0141] In step ST 102, determines a group number G _xy in accordance with Table 1, the process proceeds to step ST 103. In step ST103, it is determined whether or not x = m-1 is satisfied, that is, whether or not x has reached the last pixel (m-th pixel) of the line. If x = m-1, step ST105 is performed. Proceed to step S, otherwise step S
Proceed to T104. In step ST104, x = x + 1
Then, the process returns to step ST102, and the group number G _xy is determined for the next pixel according to Table 1, and x = m−1
Are repeated until the condition is satisfied.

At step ST105, it is determined whether or not y = n-1 holds, that is, whether or not y has reached the last line (n-th line). If y = n-1, the process proceeds to step ST107. Otherwise, step ST
Proceed to 106. In step ST106, (x, y) =
Returning to step ST102 as (0, y + 1), the group number _Gxy according to Table 1 is determined for the pixels of the next line, and step ST1 is performed until y = n-1 holds.
02 to ST104 and ST106 are repeated.
With the above processing, the group number G _xy has been assigned to all the pixels.

In step ST107, (x, y) =
(0, 0) and proceed to step ST108,
According to the first expression in Table 1, the number D _0y of light-emitting blocks D having the largest luminance weight is determined. Further, in step ST109, x = x + 1 and step S109
Proceed to T110. In step ST110, the adjacent 2
It is determined whether the group number of one pixel _satisfies G _xy > G _{(x-1) y,} and if G _xy > G _{(x-1) y} holds, that is, the pixel (x, y) if the group number G _xy is the group number G _(x-1) of the left adjacent pixel (x-1, y) is greater than _y, the process proceeds to step ST111, smaller step S
Proceed to T112.

In step ST111, the number _Dxy of light-emitting blocks (D) having the largest luminance weight is determined according to the first expression in Table 1. Therefore, pixel (x, y)
If the group number G _xy is the group number G _(x-1) of the left adjacent pixel (x-1, y) is greater than _y, the pixel (x,
The number D _{xy of} light-emitting blocks having the largest luminance weight in y) is determined according to the first expression in Table 1.

In step ST112, two adjacent two
If the pixel group number is G_xy= G_{(x -1) y}Whether or not
Is determined, and G_xy= G_{(x-1) y}If it holds,
The group number G of the pixel (x, y)_xyIs the pixel on the left
Group number G of (x-1, y) _{(x-1) y}Same as
If not, the process proceeds to step ST113, otherwise (G_xy
<G _{(x-1) y}If so, proceed to step ST114.

In step ST113, D _xy = D _{(x-1) y}
As, namely, the pixel (x, y) brightest large emitting block number D _xy the left neighbor pixel of D of the weights of the (x
−1, y) is set to be the same as the number D _{(x−1) y of the} light-emitting blocks D having the largest luminance weight. Therefore, the group number G _{xy of} the pixel (x, y) is changed to the pixel (x−1,
If it is the same as the group number G _{(x-1) y of} y), the number _{Dxy of the} light-emitting blocks having the largest luminance weight in the pixel (x, y) is determined according to the first expression in Table 1. .

In step ST114, D _xy <D _{(x-1) y}
In this case, D _xy is determined according to the second expression in Table 1. Therefore, the pixel (x, y) is smaller than the group number G _{(x-1) y} group number G _xy is left adjacent pixels of the (x-1, y), the most brightness in the pixel (x, y) The number D _{xy of} light-emitting blocks having a large weight of
Is determined according to the expression.

Then, steps ST111 and ST113 are performed.
When the processing of ST114 is performed, step ST1 is performed.
Proceeding to step 15, the same as step ST103, x
= M−1, that is, whether x has reached the last pixel (m-th pixel) of the line. If x = m−1, the process proceeds to step ST116. If not, the process returns to step ST109, where x = m-1
Are repeated until the condition is satisfied.

In step ST116, it is determined whether or not y = n-1 holds, that is, whether or not y has reached the last line (the n-th line). Ends, otherwise, step ST1
Proceed to 17. In step ST117, as in step ST106, (x, y) = (0, y + 1), and the process returns to step ST108.
The processing of T115 and ST117 is repeated until y = n-1 holds. Through the above processing, the number _{Dxy of} light-emitting blocks having the largest luminance weight in all pixels is determined. If the number _{Dxy of the} light-emitting blocks having the largest luminance weight is determined for each pixel, the combination of the light-emitting blocks for displaying each gradation level is determined.

Hereinafter, the equalizing pulse processing will be described with reference to FIGS.
This will be described with reference to the flowchart of FIG. This halftone display method can be configured by a circuit or the like.
The computer may be configured as a program to be executed according to the following flowchart. In addition, the computer program is distributed through a magnetic storage medium such as a flexible disk or a hard disk, and an optical storage medium such as a CDROM or an MO disk, or written in a nonvolatile memory device. It is distributed and used.

Here, each halftone bit data b0 to b9
Is as shown in Table 8 below.

[0152]

[Table 8]

FIG. 27 is a flowchart showing an example of processing of a halftone display method to which the present invention is applied, and shows a main path (main routine) of the equalizing pulse processing. The halftone display method to which the present invention is applied presupposes a lighting sequence in which there are a plurality of light-emitting blocks having a large luminance weight as shown in FIG. FIG.
As shown in (1), equalization pulse processing (halftone display processing)
Is started, in step ST1, N = 9 is set, and the process proceeds to step ST2. Here, the reference symbol N represents a bit number of the luminance signal. For example, N = 9 is the most significant signal bit (SF9: D4; 48 gradation levels), and N = 5.
Is the lower luminance signal bit (SF5: 32 gradation levels)
It shows. Note that, for example, halftone bit data of 48 gradation levels include b6, b7, and b8 in addition to b9.
A total of four halftone bit data b6 of 48 gradation levels
To b9.

Next, in step ST2, "bit switching portion detection processing" is executed for the nth frame and the (n + 1) th frame for the luminance signal of N = 9 bits, and the bit switching portion is detected for each pixel. The detection result is stored in the storage unit. Further, the process proceeds to step ST3, in which the “moving image false contour improvement process” is executed based on the detection result of the bit switching unit in step ST2, and the process proceeds to step ST4.

In step ST4, it is determined whether or not N = 6 (the least significant bit in the 48 gradation levels SF6 to SF9: SF6) is satisfied. If N = 6 (true: Ye)
s) End the equalization pulse processing, and if N = 6 (false:
No), proceed to step ST5. In step ST5,
After executing N = N-1, the process returns to step ST2, and then proceeds to steps ST3 and ST4 in order.
Steps ST2 and ST until 4 is true (N = 6)
Step 3 is repeated. Here, the determination of N = 6 in step ST4 is performed, for example, in the lighting sequence as shown in FIG. 19, by using an equalizing pulse for all four maximum grayscale levels (48 grayscale levels SF6 to SF9). This is equivalent to performing processing. Therefore, these processes vary depending on the configuration of the lighting sequence, the bit configuration that requires equalization pulse processing, and the like. For example, the light-emitting block having the largest weight is composed of seven 32 gradation levels. In the case (SF0 to SF4 are the same as in FIG.
In the case where SF11 is all 32 gradation levels), N = 11 in step ST2, and N = 5 in step ST4.
Will be determined.

FIG. 28 is a flowchart showing an example of the bit switching section detection process (step ST2) in the flowchart of FIG. As shown in FIG. 28, when the “bit switching unit detection process ST2” in the flowchart of FIG. 27 starts, in step ST21,
Initial setting is performed with j = 0, and step ST22
, Initialization is performed with i = 0. Here, reference numerals i and j indicate the horizontal and vertical positions (pixel numbers) of the pixels. Note that the pixel number i in the horizontal direction is
And the vertical pixel number j both start from “0”,
The horizontal direction has a size of k, and the vertical direction has a size of m.
That is, the number of pixels is (k + 1) in the horizontal direction and (m + 1) in the vertical direction.

Next, the operation proceeds to step ST23, where the frame number n of the coordinates (0,0) and the halftone bit data b9 _(n) and b9 _{(n + 1)} of _{(n + 1)} are read, and the operation proceeds to step ST24. In step ST24, the halftone bits read in step ST23 are compared, and a value (y _ij ) according to Table 9 below is written in the storage means.

[0158]

[Table 9]

Further, the process proceeds to step ST25, where the coordinate numbers in the horizontal direction are compared (i = k), and the pixel number i in the horizontal direction is determined.
Does not match k (that is, if the result of the comparison indicates that the pixel number i in the horizontal direction is smaller than the number k of pixels in the horizontal direction),
Proceeds to step ST26 to set i = i + 1 and step S
Returning to T23, the same processing is repeated until i = k is satisfied in step ST25 (that is, for pixels from one end of the same line to the other). Step ST25
If it is determined that i = k holds in step ST27, step ST27
Proceed to.

In step ST27, the coordinate numbers in the vertical direction are compared (j = m), and if the pixel number j in the vertical direction does not match m (that is, as a result of the comparison, the vertical line number j is If it is smaller than the maximum display line number m, the process proceeds to step ST28, sets j = j + 1, returns to step ST22, and repeats the same processing until j = m is satisfied in step ST27. Step ST2
If it is determined in step 7 that j = m is satisfied, the bit switching unit detecting process ST2 is terminated, and the process returns to the main routine (FIG. 2).
7 to step ST3).

FIG. 29 is a flowchart showing an example of the moving image false contour improvement process (step ST3) in the flowchart of FIG. Here, this flowchart mainly shows the “motion amount detection processing subroutine (ST35)”.
And "Equalization pulse adjustment subroutine (ST3
6)], and these processes will be described later with reference to FIG.
32 and 33 to 35 will be described in detail. Here, the entire processing flow will be described without referring to the operations of the subroutines of steps ST35 and ST36.

As shown in FIG. 29, when the “moving image false contour improvement process ST3” in the flowchart of FIG. 27 is started, in step ST31, initial setting is made with j = 0, and in step ST32, i is set. =
Initial setting is made as 0. Where reference numerals i and j
Corresponds to the pixel number in the horizontal direction (search dot) and the position in the vertical direction (processing line number).

Then, the process proceeds to a step ST33, where y ₀₀ at the coordinates (0, 0) is read and the value of y ₀₀ is changed to b or c.
(Ie, carry / decrease of the intermediate gradation level) is determined. If it is determined in step ST33 that there is carry / lower, the process proceeds to step ST34, and if it is determined that there is no carry / lower, step S34 is performed.
Proceed to T37.

In step ST34, it is determined whether or not the equalizing pulse has been adjusted for the pixel currently being searched for based on the processing result of another pixel in the current frame. And
If it is determined in step ST34 that the equalization pulse has been adjusted, the process proceeds to step ST37. If it is determined that the equalization pulse has not been adjusted, the process proceeds to step ST3.
The process proceeds to step ST5, where the "motion amount detection process" is performed. Further, the process proceeds to step ST36, where the "equalization pulse adjusting process" is performed, and then the process proceeds to step ST37.

In step ST37, it is determined whether or not the horizontal position i of the pixel currently being searched is the maximum value k of the horizontal pixel, and the horizontal pixel number i is determined to be the maximum horizontal pixel k.
Does not match, the process proceeds to step ST38, where i = i +
The process returns to step ST33 as 1 and the same processing is repeated until i = k is satisfied in step ST37 (that is, for pixels from one end of the same line to the other end). If it is determined in step ST37 that i = k is satisfied, the process proceeds to step ST39.

In step ST39, if the vertical line number j does not match the maximum display line number m in the vertical direction, the process proceeds to step ST30, where j = j + 1, and the process returns to step ST32. The same processing is repeated until the condition is satisfied. Step ST39
If it is determined that j = m is satisfied, the processing of improving the false contour of the moving image ST3 is terminated, and the process returns to the main routine (proceeds to step ST4 in FIG. 27).

FIGS. 30 to 32 are flowcharts showing an example of the motion amount detection process ST35 in the flowchart of FIG. 29. The flowchart of FIG. 30 shows the motion amount detection process in the horizontal direction. The flowchart shows a vertical motion amount detection process. Here, the subroutine (motion amount detection processing ST35) shown in FIGS. 30 to 32 is performed when a carry or a carry (carry / under) occurs in the pixel ij (y _ij = b or c). Is set to start.

As shown in FIG. 30, when the motion amount detection process (horizontal motion amount search process) starts, step S is executed.
At T41, the pixel (i, j) in which the carry pulse has been added / decreased and the equalization pulse has not yet been adjusted is set as the coordinate of the motion search start pixel, and this coordinate is renewed (X _s , Y _s ).
Is stored until this subroutine ends.

Next, in step ST411, 1 is subtracted from the search start position i in the horizontal direction and is set again as i (i = i-1), and the process proceeds to step ST412. In step ST412, it is determined whether or not the search pixel is over the panel display area (i <0). If it is determined that the search pixel is over the panel display area, the process proceeds to step ST415, and If it is determined that the time has not exceeded, the process proceeds to step ST413.

In step ST413, the coordinates (Y _s, i) of the pixel being searched and the state change Y _iys, Y _XsYs of the pixel at the coordinates where the search is started are compared.
The process returns to step ST411 if they are the same, and the same processing is repeated until they become different and until the end of the horizontal display screen is reached. Step ST
At 414, 1 is added to the position i of the pixel for which the search has been completed, and the position X _ea of the leading coordinate in the state of carry / borrow (carry or borrow) in the horizontal direction is obtained (X _ea =
i + 1). Also, in step ST415, if the state of carry / borrow in the horizontal direction continues to the end of the display area, X _ea = 0 is set. In this way,
Retrieval processing of the amount of movement in the left lateral direction (upward retrieval processing) is executed.

When the processes in steps ST414 and ST415 are completed, the process proceeds to step ST416, and the following horizontal rightward motion amount search process is executed. In step ST416, the horizontal search start position i is set again as i = X _S, and the process proceeds to step ST42, where 1 is added to the horizontal search start position i, and i is again set.
(I = i + 1). Then, the process proceeds to step ST43, where it is determined whether or not i obtained in step ST42 exceeds the horizontal display area k (i> k). If it is determined that i is over, the search operation is terminated. Step ST
The process proceeds to 47, and if it is determined that there is no overrun, the process proceeds to step ST44.

[0172] In step ST44, the new lateral search pixels the coordinates (i, y _s) is made the same Determine if the bit switches state position of the search start pixel, state the same _(y iYs = y _{If XsYs} ), the process returns to step ST42, and the same processing is repeated until it is determined in step ST44 that the state is different. Then, step ST44
If it is determined that the states are different, the search process ends and the process proceeds to step ST45. Here, step ST45 is
This is executed when the end position of the search pixel in the horizontal direction does not reach the end of the display pixel, and the horizontal coordinate i of the search end position
_Is subtracted from 1 and the value is stored as X _eb (X _eb = i-1).

Further, in step ST451,
X obtained in step ST45_ebIs X _eb= 0
Is determined. In step ST451, X_eb= 0
When it is determined that X is_eb
If it is determined that the value is not 0, the process proceeds to step ST46.
No. In step ST46, X_eaIs X_ea= 0
It is determined whether or not_ea= 0
Then, the process proceeds to step ST49, where X_ea= 0 not
Is determined, the process proceeds to step ST48.

On the other hand, in step ST47, pixel X_eaBut
It is determined whether or not the display has started from the display start position.
However, the search start pixel started from the display start position
(X_ea= 0), the process proceeds to step ST52,
If it is determined that it has not been started, step ST5 is executed.
You will go to 1. In step ST48, the horizontal direction
Motion amount B_XsYsTo B_XsYs= X_eb-X_ea+1 and horizontal
The pixel shape at both ends of the pixel where the direction bit was switched
State (α, β) = (Y_{Xea-1, Ys,}Y_{Xeb + 1, Ys})
To remember. In step ST49, B_XsYs= X
_eb+1 and (α, β) = (Y_{0, Ys,}Y_{Xeb + 1, Ys})When
In step ST50, B_XsYs=
1, and (α, β) = (Y_{0, Ys ,}Y_{0, Ys})
In step ST51, B_XsYs= KX_ea+
1, and (α, β) = (Y_{Xea-1, Ys,}Y_{k, Ys}As)
In step ST52, B is obtained and stored._XsYs
= K + 1 and (α, β) = (Y_{0, Ys,}Y_{k, Ys})age
Find and memorize. Thereby, each step ST48,
In ST49, ST50, ST51, ST52, horizontal
Amount of motion in two directions and two pixel states sandwiching consecutive pixels
Is searched, and then the process proceeds to step ST53.
No.

As shown in FIG. 31, step ST5
At 3, subtract 1 from the search start position j in the vertical direction, set j again (j = j-1), and proceed to step ST54. At this time, the position of the search pixels in the horizontal direction is X _s. In step ST54, it is determined whether or not the search pixel is over the panel display area (j <0). If it is determined that the search pixel is over the panel display area, the process proceeds to step ST57. If it is determined that the time has not exceeded, the process proceeds to step ST55.

In step ST55, the coordinates (X _s , j) of the pixel being searched and the state change Y _Xsj, Y _XsYs of the pixel at the coordinates where the search is started are compared.
Then, if they are the same, the process returns to step ST53, and the same processing is repeated until they become different and until the end of the vertical display screen is reached. Step ST5
In step 6, 1 is added to the position j of the pixel for which the search has been completed, and the position Y _ea of the leading coordinate in the vertical carry / carry (carry or borrow) state is obtained (Y _ea = j).
+1). Also, in step ST57, if the vertical carry / borrow state continues to the end of the display area, Y _ea = 0 is set. In this manner, the vertical motion amount search processing (upward search processing) is performed.

When the processing of steps ST56 and ST57 is completed, the process proceeds to step ST58, where the following vertical motion amount search processing (downward search processing) is executed. In step ST58, the vertical search start position j is set again as j = Y _S, and
Proceeding to 59, 1 is added to the vertical search start position j and j is set again (j = j + 1).

Next, the process proceeds to step ST60, where it is determined whether or not the position j of the search pixel exceeds the display area m in the vertical direction (j> m). If not, step S
Proceed to T61. In step ST61, it is looking for the coordinates of the pixel (X _s, j) and the pixel of the coordinates at which to start the search condition change Y _XSJ, compare Y _XSYS, Different step ST6
2 and if the same (Y _Xsj = Y _XsYs ), step S
The process returns to T59, and the same processing is repeated until it becomes different and reaches the end of the display screen in the vertical direction.

As shown in FIG. 32, step ST6
In step 2, 1 is subtracted from the pixel position j for which the search has been completed, and the position Y _eb of the coordinate on the rear side in the state of carry / borrow (carry or borrow) in the vertical direction is obtained (Y _eb = j−1). ),
Further, the process proceeds to step ST63. In step ST63, it is determined whether or not Y _eb obtained in step ST62 satisfies Y _eb = 0, and it is determined that the coordinate Y _eb = 0 on the rear side of the vertical carry / borrow state is established. The process proceeds to step ST67. If it is determined that Y _eb = 0 is not established, the process proceeds to step ST64.

In step ST64, it is determined whether or not the start coordinate Yea of the state change is at the end of the screen (= 0).
If it is not the end of the screen, the process proceeds to step ST65, and if it is the end of the screen (Yea = 0), the process proceeds to step ST66. Similarly, also in step ST68, the start coordinate Yea of the state change
Is determined to be an edge of the screen, and if it is not the edge of the screen, the process proceeds to step ST69, and if it is the edge of the screen, (Yea =
0) Go to step ST70.

In step ST65, the vertical movement amount C
_XsYsTo C_XsYs= Y_eb-Y_ea+1 and the vertical
The pixel state (γ,
δ) = (Y_{Xs, Yea-1,}Y_{Xs, Yeb + 1}Remember asking)
Then, in step ST66, C _XsYs= Y_eb+1 and
(Γ, δ) = (Y_{Xs, 0,}Y_{Xs, Yeb + 1}Remember asking)
Then, in step ST67, C_XsYs= 1 and (γ,
δ) = (Y_{Xs, 0,}Y_{Xs, 0})
In step ST69, C_XsYs= M-Y_ea+1 and (γ,
δ) = (Y_{Xs, Yea-1,}Y_{Xs, m})
Then, in step ST70, C_XsYs= M + 1, and
(Γ, δ) = (Y_{Xs, 0,}Y_{Xs, m})
You. As a result, the vertical movement as well as the horizontal movement amount
The amount of motion is also searched, and the motion amount detection process ST35 ends,
Return to the routine (proceed to step ST36 in FIG. 29).
Mu).

FIGS. 33 and 34 (FIG. 35) are flowcharts showing an example of the equalizing pulse adjusting process ST36 in the flowchart of FIG. As shown in FIG. 33, when the equalizing pulse adjusting process ST36 starts, in step ST71, the horizontal pixels (α, β) sandwiching the searched motion area are (a, d) and (d, a). (Condition 1) is determined, and the determination result is true (Ye
If s), the process proceeds to step ST72, and if false (No), the process proceeds to step ST76.

At step ST72, the searched motion area is determined.
The vertical pixels (γ, δ) sandwiching the region are (a, d) and
It is determined whether or not (d, a) (condition 2).
If the result is true, the process proceeds to step ST73.
Proceed to step ST74. Further, in step ST73
Is the amount of movement B in the horizontal and vertical directions_XsYsAnd C_XsYsBut
C _XsYs≧ B_XsYs(Condition 3), C_XsYs≧ B
_XsYsIf it is determined that the condition is satisfied, the process proceeds to step ST74.
If it is determined that the condition is not satisfied, step ST75
Proceed to.

Similarly, in step ST76, the search
The vertical pixels (γ, δ) sandwiching the moving area are (a, d)
And (d, a) are determined (condition 2), and
If the determination result is true, the process proceeds to step ST75, and
If so, the process proceeds to step ST77. Further, step ST7
7, the horizontal and vertical movement amounts B_XsYsAnd C
_XsYsIs C_XsYs≧ B_XsYs(Condition 3), C
_XsYs≧ B_XsYsIf it is determined that the condition is satisfied, step ST7 is performed.
8 and if it is determined that the condition is not satisfied, step S
Proceed to T79.

In step ST74, the motion amount V_XsYs, Dynamic
Pixel (ε, ζ) sandwiching the distance and the detection start pixel
Y_XsYsIs stored (V_XsYs= B_XsYs, (Ε, ζ) =
(Α, β), Y_XsYs). Similarly, in step ST75
Is V_XsYs= C_XsYs, (Ε, ζ) = (γ, δ), Y_XsYs
Is stored. In step ST78, the motion amount V
_{Xs Ys}, Pixel sandwiching the amount of motion, and detection start pixel Y
_XsYsIs stored (V_XsYs= B_XsYs, (Ε, ζ) =
(Α, β), Y_XsYs). Further, in step ST79
Is V_XsYs= C_XsYs, (Ε, ζ) = (γ, δ), Y_XsYs
Is stored. Then, steps ST74 and ST7
When the process of step 5 is completed, the process proceeds to step ST80, and
When the processing in steps ST78 and ST79 is completed, step
Proceeding to step ST84, the equalizing pulse for motion compensation
To adjust.

As shown in FIG. 34, step ST8
0, a look-up table (LU
The row corresponding to the motion amount V _XsYs detected by T) is selected, and the process proceeds to step ST81 to select which of the positive and negative equalization pulses is to be applied depending on the state of Y _XsYs .
Further, in step ST82, the weighting direction of the equalization pulse is determined by the pixels (ε, ζ) sandwiching the motion amount,
Proceeding to step ST83, the pixels (ε,
Weighted equalizing pulses are sequentially added to the region sandwiched by (ζ), the equalizing pulse adjusting process ST36 is completed, and the process returns to the main routine (proceeds to step ST37 in FIG. 29).

On the other hand, in step ST84, an equalization pulse similar to that of the prior art according to the state of the detection start pixel Y _XsYs by the look-up table LUT (FIGS. 27 and 3)
5) is selected. Further, step S
Proceeding to T85, the equalizing pulse is sequentially added to the region sandwiched by the pixels (ε, む) sandwiching the motion amount, the equalizing pulse adding / decreasing process ST36 ends, and the process returns to the main routine (step ST37 in FIG. 29). Proceed to).

FIG. 35 is a diagram for explaining a modification of the equalizing pulse adding / subtracting process shown in FIGS. 33 and 34.
5 (a) and FIG. 35 (b) show a modification of the process between reference characters F to G in the equalization pulse adjusting process shown in FIGS. 33 and 34, respectively. That is,
Steps ST77 to ST79 and steps 84 and ST85 in FIGS. 33 and 34 correspond to steps ST86 and ST87 shown in FIG. 35A or FIG. 35B.
Can be processed as step ST88 shown in FIG.

As shown in FIG. 33, FIG. 34 and FIG. 35 (a), in step ST76, the vertical pixels (γ, δ) sandwiching the searched motion area are (a, d) and (d, If it is determined that it is not a), the process proceeds to step ST86 in FIG. 35 (a) instead of proceeding to step ST77 in FIG. In step ST86, an equalization pulse according to the state of the detection start pixel Y _XsYs is selected by a look-up table LUT provided in advance, and further,
Proceeding to step ST87, the equalizing pulse corresponding to the state of Y _XsYs is sequentially added only to the coordinates (X _s, Y _s ), and the equalizing pulse adjusting process ST36 ends, and the process returns to the main routine (FIG. The process proceeds to step ST37 in 29). Thus, steps ST77 to ST77 in FIGS.
ST79 and steps 84 and ST85 are described in FIG.
The processing can be performed as steps ST86 and ST87 shown in FIG.

Further, FIGS. 33, 34 and 35
As shown in (b), in step ST76,
When it is determined that the vertical pixels (γ, δ) sandwiching the searched motion area are not (a, d) and (d, a),
Instead of proceeding to step ST77 in FIG.
The process proceeds to step ST88 in (b), ends the equalization pulse adjusting process ST36 without adding an equalization pulse, and returns to the main routine (proceeds to step ST37 in FIG. 29). That is, step ST in FIG. 33 and FIG.
77 to ST79 and steps 84 and ST85 in FIG.
The processing may be performed as step ST88 shown in FIG.

As described above with reference to the flowcharts of FIGS. 27 to 35, the halftone display method to which the present invention is applied is particularly suitable for moving images of various moving speeds and moving directions. For example, even for a high-speed moving image whose moving speed exceeds 5 pixels / frame, it is possible to reduce disturbance of halftone display and improve false contours of a moving image of a video.

FIG. 36 is a diagram showing an example of a display image on a display device to which the halftone display method according to the present invention is applied. FIG. 37 shows a case where the present invention is applied to the display image shown in FIG. It is a figure for demonstrating a subject, and is related to FIG.20 and FIG.22 mentioned above. In the above-described embodiment of the halftone display method according to the present invention, for example, in the display panel, only one pixel PXL32 is 160-BB.
When the other pixel is 159-AA, as shown in FIG. 37, the pixel PXL33 becomes the PXL32 (160
-BB: 160 gray level display using three 48 gray level light emitting blocks), and 159 gray level display (159-BB) using three 48 gray level light emitting blocks. The pixels PXL34 and PXL35 are also 159-BB. That is, the above-described halftone display method uses the weighting of the redundant light-emitting block to determine its own light-emitting pattern by the light-emitting pattern of an adjacent pixel. As shown in FIG. By aligning the light emission patterns of PXL33 to PXL35 with the adjacent pixels PXL32 (160-BB) (159-BB), speed detection for each line is accurately performed.

Note that, similarly to the above, the reference numeral AA
Indicates, for example, a case where gradation display is performed using two (D1, D2) light-emitting blocks of 48 gradation levels (light-emitting blocks having the largest luminance weight), and reference numeral BB
Represents three light-emitting blocks of 48 gradation levels (D1, D2,
D3) shows a case where gradation display is performed by using D3). Therefore, 159-AA is equivalent to two light emitting blocks of 48 gradation levels.
Are used to display 159 gradation levels.
59-BB indicates a pixel displaying 159 gray levels using three light emitting blocks of 48 gray levels, and
Reference numeral 160-BB denotes a pixel that displays 160 gray levels using three 48 gray level light emitting blocks.

The above description relates to one line, and when an actual flat display panel is considered, there are the following problems to be solved. That is, FIG.
6 and FIG. 37, for example, the pixel PXL
When only 32 is 160-BB and the other pixels are 159-AA, if the image on the display panel moves in the horizontal direction (horizontal direction), speed detection can be performed accurately and there is no problem. However, if this image moves in the vertical direction, the same problem as described with reference to FIG. 20 occurs in one vertical line (column), and the false contour of the moving image is hardly reduced. In addition, since the light emission states are aligned in a line (a plurality of pixels), the disturbance also occurs in a line shape. Since this line-shaped disturbance appears at a place different from the place where the false contour of the moving image normally occurs, the disturbance is easily recognized.

In another embodiment of the present invention described below, as described above, even if a singular point such as a noise having a different gradation from the surrounding pixels, if it is adjacent to the pixel, Eliminating line-like disturbances that occur to determine the light emission pattern by learning, aligning the light emission pattern as much as possible in both the horizontal and vertical directions, and reducing the adverse effects due to singular points such as noise. Is applied more effectively. Another embodiment of the present invention can be applied to the above-described display device shown in FIG. 21 as it is.

In another embodiment of the present invention, one frame (one field) is composed of a plurality of light-emitting blocks, and among the light-emitting blocks, the light-emitting block with the largest luminance weight (the light-emitting block with the largest luminance weight) is used. ) Is applied to a halftone display method and a display device using a lighting sequence in which a plurality of lighting sequences are provided. FIGS. 38 to 41 are diagrams for explaining another embodiment of the halftone display method according to the present invention. In each of the drawings, the original light emission pattern of each pixel is shown in FIG. Things (for example,
The light emission pattern is defined by minimizing the number of light emission blocks having the maximum luminance), and the pixel to be processed (pixel of interest) is the pixel PXL33. In the following description of each embodiment, in order to make it easier to understand other modes of the present invention, the original light emission pattern of each pixel will be referred to one other than that shown in FIG.

FIG. 38 is a diagram for explaining a first embodiment of another embodiment of the halftone display method according to the present invention. FIG.
In the first embodiment, as shown in FIG.
33, four surrounding pixels (reference pixels) PX
The light-emitting block used by the pixel of interest PXL33 is defined with reference to the light-emitting block used by L22, PXL23, PXL24, and PXL32. Specifically, in the case of FIG. 38, three reference pixels PXL2
2, PXL23 and PXL24 are 159-AA, and one reference pixel PXL32 is 160-BB.
The majority determination of these four reference pixels is performed, and the usage state of the light-emitting blocks exceeding the majority (159-AA: two light-emitting blocks of 48 gradation levels are used) indicates the target pixel PXL3.
The light emission pattern of No. 3 is defined as 159-AA (two light emission blocks of 48 gradation levels are used).

Here, for example, in FIG. 38, three reference pixels PXL22, PXL23 and PXL24 are 160
In the case of −BB, if one reference pixel PXL32 is 159-AA, the pixel of interest is determined based on the usage status of the light-emitting block that exceeds the majority (160-BB: three light-emitting blocks of 48 gradation levels are used). The light emission pattern of the PXL 33 is 159-BB (3 light emission blocks of 48 gradation levels).
Use).

For example, in FIG. 38, when the two reference pixels PXL22 and PXL23 are 159-AA and the two reference pixels PXL24 and PXL32 are 160-BB, that is, when the result of the majority decision is the same, Is
15 without changing the light emission pattern of the pixel of interest PXL33
9-AA (specifying the light emission pattern with the number of light emission blocks having the maximum luminance being the minimum) may be used. If the target pixel is the upper left pixel PXL11, there is no reference pixel for the target pixel PXL11. In this case, for example, a light-emitting block having the highest luminance (for example, 48 gradations) The processing may be performed by setting the number of light emitting blocks of the level to 0 (therefore, the target pixel PX)
L11 maintains the original light emission pattern).

Accordingly, as in the description of the halftone display method of the present invention described above, for example, the first expression in which the number of used light-emitting blocks having the largest luminance weight for one gray scale and the least luminance weight When the number of large light-emitting blocks that can be used can be expressed in two ways in the second expression, the number of light-emitting blocks with the largest luminance weight in the target pixel PXL33 is determined by the reference pixels PXL22 and PXL2.
3, the number of light-emitting blocks having the largest luminance weight in PXL24 and PXL32 is determined by majority decision.
That is, the number of light-emitting blocks having the largest luminance weight used in the target pixel PXL33 is the reference pixel PXL2.
2, when the number of light-emitting blocks having the largest luminance weight in PXL23, PXL24, and PXL32 is different (group numbers GA and GB: see Table 1), the number NA of reference pixels of group number GA and the reference pixels of group number GB Is determined by majority decision with the number NB.

When NB <NA: first expression (expression by group number GA) When NB = NA ... (original expression of target pixel) When NB> NA: second expression (group number GA) FIG. 39 shows a second half of another embodiment of the halftone display method according to the present invention.
It is a figure for explaining an example.

In the above-described first embodiment, even when the number of reference pixels is even, there is a case where the number of reference pixels is the same by majority, but in the second embodiment, the number of reference pixels is odd. That is, in the second embodiment, 4 in FIG.
Reference pixels PXL22, PXL23, PXL24, P
One reference pixel PXL42 is added to XL32 to make five (odd) reference pixels. here,
As the reference pixels, the original light emission pattern of each pixel (a light emission pattern in which the number of light emission blocks having the maximum luminance is defined as a minimum) may be used, but the light emission pattern after performing the sequential processing is used. You may. Therefore, for example, the target pixel moves from left to right (PXL11 → PXL12 → PXL13, →) in each line (for example, Y1), and further moves downward from above (Y1 → Y2 → Y3 →).
In the second embodiment, when the processing is performed while moving, the reference pixels PXL22, PXL23, PXL24, and PXL32 are pixels having the light emission pattern after the processing, and the reference pixel PXL42 is the pixel having the original light emission pattern before the processing. Pixel.

FIG. 40 is a diagram for explaining a third embodiment of another embodiment of the halftone display method according to the present invention. In the first and second embodiments shown in FIG. 38 and FIG. 39 described above, pixels (PXL22, PXL23, PXL24, PXL32;
PXL42) as a reference pixel,
In the third embodiment shown in FIG. 40, four pixels (PXL22, PXL2) directly adjacent to the pixel of interest PXL33.
3, PXL24, PXL32) as well as the target pixel P
Seven pixels (PXL11, PXL12, PXL13, PXL14, PXL11, PXL12, PXL14,
PXL15, PXL21, and PXL31) are also used as reference pixels, that is, majority processing is performed using eleven reference pixels around the target pixel PXL33.

FIG. 41 is a view for explaining a fourth embodiment of another embodiment of the halftone display method according to the present invention. Book 4
In the embodiment, the same pixels PXL22, PXL23, PXL24, PXL32, PXL as in the second embodiment shown in FIG.
Although XL42 is used as a reference pixel, each reference pixel is weighted. Specifically, the reference pixel PXL
22 is weighted by “3”, and the reference pixel PXL2
3, weight PXL32 with “2”, and
The reference pixels PXL24 and PXL42 are weighted by “1”. Therefore, in the above-mentioned majority decision processing, the magnitude of the designated weight is multiplied for each reference pixel, and the result is decided by majority decision.

For example, when processing is performed based on the original light emission pattern, in FIG. 41, when the reference pixel PXL22 is also 160-BB, that is, the reference pixel PXL22 having the weight “3” and the reference pixel PXL32 having the weight “2” Is 1
60-BB and other reference pixels PXL23, PXL24, P
When XL42 is 159-AA, the pixel of interest PXL33 is 159-AA in the above-described second embodiment, but the pixel of interest PXL33 is 159-BB in the fourth embodiment.

As described above, in the first to fourth embodiments of the other embodiments of the present invention, how to determine each reference pixel or the number of reference pixels,
Further, how to assign weights to the reference pixels and the like are merely examples, and it goes without saying that various changes can be made. As described above, according to another embodiment of the present invention, for example, even if there is a singular point such as noise having different gradation from the surroundings, the light emission state of each pixel can be made uniform in a planar manner. A more accurate motion compensation equalization pulse can be effectively added.

As a display device to which the present invention is applied, in addition to a gas discharge panel such as a plasma display,
Various display devices that perform halftone display by a time division method within a frame or a field, such as a DMD (Digital Microm
As described above, the present invention can be applied to an irror device) or an EL panel.

[0208]

As described above in detail, according to the present invention, there is provided a lighting sequence having redundancy which can express one gradation display by combining a plurality of types of sub-frames (light-emitting blocks). When used, it is possible to reduce the occurrence of false contours (color false contours) of video by actively utilizing the redundancy, and display by applying the motion compensation equalization pulse method effectively. Image quality can be further improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a conventional lighting sequence of each subframe.

FIG. 2 is a diagram illustrating an example of a lighting state of each sub-frame when intermediate gray levels are 127 and 128;

FIG. 3 is a diagram illustrating lighting states in a first frame and a second frame.

FIG. 4 is a diagram for explaining an example of a cause of occurrence of disturbance of halftone luminance in an example of a conventional halftone display method.

FIG. 5 is a diagram for explaining another example of a cause of occurrence of disturbance of halftone luminance in an example of a conventional halftone display method.

FIG. 6 is a diagram for explaining still another example of a cause of occurrence of disturbance of halftone luminance in an example of a conventional halftone display method.

FIG. 7 is a diagram illustrating an example of a subframe separation state when the intermediate gray level changes from 31 to 32;

8 is a diagram illustrating an example of a separated state of subframes when rightward scrolling is performed in the specific example illustrated in FIG. 7;

FIG. 9 is a diagram illustrating an example of a subframe separation state when the intermediate gray level changes from 32 to 31;

FIG. 10 is a diagram showing a state where a display image is scrolled.

FIG. 11 is a diagram for explaining a problem that occurs when a display image is scrolled from left to right.

FIG. 12 is a diagram for explaining a problem that occurs when a display image is scrolled from right to left.

FIG. 13 is a diagram for explaining another example of a conventional halftone display method.

FIG. 14 is a block diagram showing an example of a conventional luminance adjusting light emitting block insertion circuit.

FIG. 15 is a diagram (part 1) for explaining still another example of the conventional halftone display method.

FIG. 16 is a diagram (part 2) for explaining still another example of the conventional halftone display method.

FIG. 17 is a diagram (part 3) for explaining still another example of the conventional halftone display method.

FIG. 18 is a diagram (part 4) for explaining still another example of the conventional halftone display method.

FIG. 19 is a diagram showing an example of a conventional lighting sequence of each sub-frame targeted by the present invention.

20 is a diagram for describing a problem in the lighting sequence shown in FIG.

FIG. 21 is a block diagram schematically showing an example of a display device to which the present invention is applied.

FIG. 22 is a diagram for explaining the principle of the halftone display method according to the present invention.

FIG. 23 is a flowchart schematically showing a halftone display method according to the present invention.

FIG. 24 is a flowchart illustrating an example of a halftone display method according to the present invention.

FIG. 25 is a flowchart (part 1) illustrating an operation of an example of a halftone display method according to the present invention.

FIG. 26 is a flowchart (part 2) illustrating an operation of an example of a halftone display method according to the present invention.

FIG. 27 is a flowchart illustrating an example of processing of a halftone display method to which the present invention is applied.

FIG. 28 is a flowchart illustrating an example of a bit switching unit detection process in the flowchart of FIG. 27;

FIG. 29 is a flowchart illustrating an example of a moving image false contour improvement process in the flowchart of FIG. 27;

FIG. 30 is a flowchart (part 1) illustrating an example of a motion amount detection process in the flowchart of FIG. 29;

FIG. 31 is a flowchart (part 2) illustrating an example of a motion amount detection process in the flowchart of FIG. 29;

FIG. 32 is a flowchart (part 3) illustrating an example of a motion amount detection process in the flowchart of FIG. 29;

FIG. 33 is a flowchart (part 1) illustrating an example of an equalizing pulse adjusting process in the flowchart of FIG. 29;

FIG. 34 is a flowchart (part 2) illustrating an example of the equalization pulse adjusting process in the flowchart of FIG. 29;

FIG. 35 is a diagram for explaining a modification of the equalization pulse adding / subtracting process shown in FIGS. 33 and 34.

FIG. 36 is a diagram showing an example of a display image on a display device to which the halftone display method according to the present invention is applied.

FIG. 37 is a diagram for describing a problem when the present invention is applied to the display image shown in FIG. 36;

FIG. 38 is a diagram for explaining a first embodiment of another mode of the halftone display method according to the present invention.

FIG. 39 is a diagram illustrating a second embodiment of another mode of the halftone display method according to the present invention.

FIG. 40 is a diagram for explaining a third embodiment of another mode of the halftone display method according to the present invention.

FIG. 41 is a diagram for explaining a fourth embodiment of another mode of the halftone display method according to the present invention.

[Explanation of symbols]

Reference Signs List 100 display apparatus 102 image display unit 131 X decoder 132 X driver 141 Y decoder 142 Y driver 105 control unit 200 light emitting block selection and luminance adjustment light emitting block insertion means 310 delay means 400 luminance adjustment Light emitting block adding means for use 410 ... Equalizing pulse discriminating means 410a ... Comparison unit 410b ... Lookup table (LUT) 420 ... Equalizing pulse adding means D (D1 to D4) ... Light emitting block with the largest luminance weight (48 gradations) EPA, EPS ... Equalization pulse

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tomokazu Shiga 568 Kitanocho, Hachioji-shi, Tokyo 506 Fort Kitano 506 (72) Inventor Ewen Zoo 5-26-3 Tamagawa, Chofu-shi, Tokyo Heights Kuji 103 (72) Inventor Kazuki Sawa Spring Court 108 2-39-3 Ueishihara, Chofu City, Tokyo (72) Inventor Kiyoshi Igarashi 1-46-15, Honan, Suginami-ku, Tokyo (72) Inventor Kosaku Toda Kamikodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture 4-1-1, Fujitsu Limited (72) Inventor Takayuki Oe 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited (72) Inventor, Toshio Ueda Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture 4-1-1 1-1 Fujitsu Limited (72) Inventor Noriharu Kariya 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Inside the corporation

Claims (4)

[Claims] 1. A halftone which has a plurality of predetermined light-emitting blocks in each frame or field for displaying an image, and is capable of displaying one gradation level by a combination of a plurality of light-emitting blocks. A display method, comprising: determining a light emitting block to be used for gradation display of an arbitrary first pixel based on a use state of the light emitting block in a second pixel adjacent to the first pixel. Wherein a light emitting block to be used is selected by a predetermined procedure. 2. A display device having a plurality of predetermined light-emitting blocks in each frame or field for displaying an image and capable of displaying one gradation level by combining a plurality of light-emitting blocks. An image display unit, a driving unit that drives the image display unit, a control unit that controls the driving unit, and a light emitting unit that selects a light emitting block and inserts a luminance adjusting light emitting block with respect to an original signal. A light-emitting block insertion unit for block selection and brightness adjustment, wherein the light-emitting block selection and brightness adjustment light-emitting block insertion unit includes a first light-emitting block for determining a light-emitting block used for gradation display of an arbitrary first pixel. The light emitting block used by the first pixel is selected in accordance with a predetermined procedure from the usage status of the light emitting block in the second pixel close to the pixel. Display device, characterized in that turned. 3. A halftone which has a plurality of predetermined light-emitting blocks in each frame or field for displaying an image, and which can display one gradation level by a combination of a plurality of light-emitting blocks. A display method, comprising: determining a light-emitting block to be used for gradation display of an arbitrary first pixel based on a usage state of the light-emitting block in at least two or more reference pixels surrounding the first pixel.
A light-emitting block to be used by the pixel is selected by a predetermined procedure. 4. A display device having a plurality of predetermined light-emitting blocks in each frame or field for displaying an image and capable of displaying one gradation level by a combination of a plurality of light-emitting blocks. An image display unit, a driving unit for driving the image display unit, a control unit for controlling the driving unit, and light emission for selecting a light emitting block and inserting a luminance adjusting light emitting block with respect to an original signal. A light-emitting block insertion unit for block selection and brightness adjustment, wherein the light-emitting block selection and brightness adjustment light-emitting block insertion unit includes a first light-emitting block for determining a light-emitting block used for gradation display of an arbitrary first pixel. From the usage status of the light-emitting block in at least two or more reference pixels around the pixel
A light-emitting block to be used by the pixel of the display device is selected by a predetermined procedure.