JPH1039830A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the turbulence of assigning intensity levels without replacing the order of subfields in a field unit or the like especially by selectively flattening a signal as to parts becoming an eyesore when the turbulence of the assiging intensity levels is caused while performing the reducing of a noise component in the prescribed parts of an input image to reduce a frequency in which the turbulence of the assiging intensity levels is caused. SOLUTION: An image is divided into two areas of first and second areas by a first area selecting circuit 40 and a second area selecting circuit 50. A signal being the output of the first area selecting circuit 40 is made so that the noise component is, moreover, eliminated by a noise reducing circuit 60 to become a signal consisting of constant values in a certain section. Next, the output of a synthesizing circuit 9 obtained by synthesizing the output of the second area selecting circuit 50 and this signal is supplied to a plasma display panel 11 through a subfield control circuit 10. Thus, in the input image, image parts consisting of levels in which the turbulance of the assigning intensity levels is apt to be cansed are extracted to be selectively applied with the noise elimination.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sub-field driving method, such as a display device for displaying a multi-gradation display by dividing one field of an input image into a plurality of sub-field images and displaying them. More particularly, the present invention relates to a device for improving gradation disturbance of halftone display that occurs when displaying a moving image.

[0002]

2. Description of the Related Art Conventionally, a basic driving method of a plasma display panel using a method called a subfield driving method is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-271325.
And so on, it is intended to display a 64-tone halftone image using six subfields. However, as explained in this example,
Disorders of gray scale display have been reported, such as pseudo contours being observed when displaying a moving image in halftone. As one of the methods for reducing the disturbance of the halftone display in such a conventional image display device, Japanese Patent Application Laid-Open No.
71325. As shown in FIGS. 16, 17, 18, and 19 of the publication, this conventional improvement method can be summarized as follows: (1) The order of each subfield is changed by controlling a predetermined order. For example, the weight of each subfield is (a) 8, 16, 2, 8, 4, 1, 16, 8 or (b) 8, 16, 2, 16, 4, 1, 16, 8, etc. Switch. (2) There are two or more combinations of subfields that display a specific gradation. For example, FIG. 16 and FIG.
In No. 7, a combination using two subfields with a weight of 8 is used as a combination of subfields representing the halftone level 16, but which two of the three subfields with a weight of 8 are used. Thus, two or more combinations are made possible.

[0003] By using various combinations of these, the light emission pattern is appropriately changed and dispersed so that the gradation display pattern is not biased and the gradation display disturbance is made inconspicuous.

[0004]

Generally, the occurrence of gradation disturbance in a moving image is caused not only in a portion where gradation is continuously changed, such as a human face portion, but also in a background portion of a moving object. It has been found that significant gradation disturbance may occur even in a part where there is essentially no gradation change, such as a flat image part, but also in a part containing slight noise depending on the signal level. doing. FIG. 11 conceptually shows a relative value of the gradation display disturbance observed when the ramp waveform is moved as a moving image and is followed.
As can be seen from this figure, even when the level of the original image hardly changes, such as the background portion of the image as described above, it is particularly remarkable in a portion where the level is substantially equal to about 128, for example. The gradation display may be disturbed.

However, Japanese Patent Application Laid-Open No. 7-27132
In the conventional plasma display device disclosed in Japanese Patent Laid-Open Publication No. 5 (1999) -1995, a level portion where gradation disturbance is likely to occur is described.
Pre-processing such as noise removal is not particularly performed, and in a natural image or the like, gradation disturbance due to slight noise is apt to occur, and the improvement effect is insufficient even by the above-described method. .

Further, in this conventional method, it is necessary to change the order of subfields for each field, and when this is introduced, it is necessary to change the circuit of the part for driving the subfield. In addition, since the subfield configuration is such that there are two or more combinations of subfields that can display a specific gradation, even if the number of subfields is the same as in the related art, a single pixel can correctly represent one field. There is a big problem that the number of gradations is significantly reduced.

For example, in an example using eight sub-fields disclosed in Japanese Patent Application Laid-Open No. Hei 7-271325, the number of gradations that can be expressed by a single pixel in one field is 64 gradations, which is the original 256 floors. The number of gray scales that can be displayed significantly decreases as compared with the tone.

For this reason, attempts have been made to approximately secure the number of gradation representations by a method such as so-called error diffusion. However, the method using error diffusion tends to add a noise sensation, particularly to a still image portion. This gives the impression that coarse noise is added to the original signal, and is a major factor in lowering the evaluation of image quality.

In order to recover the reduced number of gradations that can be expressed, if the number of subfields is to be increased, the drive pulse width must be narrowed, and a new development of a high-performance panel electrode material is required. In addition, there were serious problems such as ensuring stable operation, increasing power consumption, and increasing unnecessary radiation.

[0010]

In order to solve the above-mentioned problems, an image display device according to the present invention divides one field of an input image displayed on the display device into a plurality of sub-field images and displays the image. An image display device that performs multi-tone display by reducing noise components in a predetermined portion of the input image and displaying the input image.

According to the present invention, when reducing the halftone display disturbance generated by the subfield driving method, the original gradation display performance is reduced in a still image portion where high gradation is required to be ensured. In addition, the frequency of occurrence of gradation display disturbance is high in the moving image portion, and since noise removal is performed on this portion, the frequency of occurrence of gradation display disturbance can be significantly reduced. In a part where it is difficult to completely remove the gradation disturbance such as a continuous level change part, a predetermined modulation operation is performed on the moving image signal part to disperse the position on the screen where the gradation display disturbance occurs. Is possible, and it is possible to make the gradation display disturbance inconspicuous.

Further, according to the present invention, there is no need to change the order of the subfields for each field, so that there is no need to change the circuit for the subfield driving portion. Therefore, there is also a practical advantage that the present invention can be implemented only by adding an image signal processing portion based on the present invention to a stage preceding the display device that performs the conventional subfield processing.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Claims 1 and 2 of the present invention
The image display device according to (1), wherein an image display device that divides one field of the input image displayed on the display device into a plurality of sub-field images and displays the divided images to perform multi-gradation display, An image display device characterized in that a noise component in a predetermined portion is reduced and displayed, and a noise component in a predetermined portion of an input image in the image display device according to the present invention is reduced. An image display device characterized in that high-frequency components in a region are reduced.

As described above, by performing the noise component reduction on a predetermined portion of the input image before performing the sub-field processing, it is possible to minimize the gradation disturbance in the background portion of the moving image which is particularly conspicuous. Will be possible.

According to a third aspect of the present invention, in the image display apparatus, the reduction of the noise component in the predetermined portion of the input image is a reduction in the noise component in the motion image region of the input image and its peripheral region. It is a feature.

Since the noise component is reduced by paying particular attention to the motion image area of the input image,
Effective noise reduction processing can be performed on the moving image portion without affecting the signal for the still image portion, and the frequency of occurrence of disturbance of halftone display based on subfield driving can be significantly reduced. .

According to a fourth aspect of the present invention, in the image display apparatus, the noise component in a predetermined portion of the input image is reduced by a part or the whole of the image region in the motion image region of the input image and its peripheral region. Is an image divided into regions divided for each predetermined level.

Since the noise component is reduced by paying particular attention to the moving image area of the input image and the peripheral area thereof, the signal for the still image area is not affected and the moving image area and the surrounding area are not affected. An effective noise reduction process can be performed on a peripheral still image region that enters the field of view when a moving image portion is followed, and the frequency of occurrence of disturbance in halftone display based on subfield driving can be significantly reduced.

In the image display device according to the fifth aspect of the present invention, one field of an input image displayed on the display device is divided into a plurality of sub-field images and displayed to perform multi-tone display. An image display apparatus for performing a method, wherein after reducing a noise component in a predetermined portion of the input image, a predetermined modulation operation is performed on a signal in which the noise component is reduced and displayed. The reduction of the noise component in a predetermined portion of the input image is performed by dividing the motion image region of the input image and a part of the image region in the peripheral region into an image having a certain level. As a result, the moving image area and its surrounding area can be converted into a signal having a certain value, and a change in a signal in the area can be suppressed to suppress a disturbance in gradation display that occurs when displaying a moving image. it can.

According to a sixth aspect of the present invention, in the image display apparatus, the modulation operation is an operation of adding a signal controlled based on a pixel position and an amount of motion of an image to a signal in which the noise component is reduced. An image display device characterized by the following.

After the noise component of a predetermined portion of the input image is reduced, the signal obtained by reducing the noise component is subjected to a predetermined modulation operation and displayed. In addition to being able to suppress gradation disturbance in a portion where remarkable gradation display disturbance is likely to occur, the present invention is applicable to an image portion other than a flat portion, that is, a portion in which gradation display disturbance is likely to occur, such as a portion where an image level continuously changes. In this case, it is possible to disperse the position of the portion where the gradation display disturbance has occurred by the above-mentioned predetermined modulation operation, and it is possible to obtain the effect that the gradation display disturbance can be made inconspicuous.

In the image display device according to the present invention, after reducing a noise component of a predetermined portion of the input image, a signal in which the noise component is reduced is controlled by a pixel position and a motion amount of the image. By adding and modulating the modulated signal, the position where the gradation display disturbance occurs is dispersed, and the period of the modulation signal is controlled by the image movement, so that the image movement and the position where the gradation disturbance occurs are synchronized. Thus, it is possible to prevent gradation disturbance from becoming conspicuous.

In the image display apparatus according to a ninth aspect of the present invention, after reducing a noise component of a predetermined portion of the input image, a read position of the signal with the reduced noise component is changed to a pixel position and an image position of the image. By controlling and reading out according to the amount of movement, the position where the gradation display disturbance occurs is dispersed, and by controlling the readout position by the movement of the image, the movement of the image and the position of occurrence of the gradation disturbance are synchronized and the floor is read. It is possible to prevent the disturbance from becoming conspicuous.

(Embodiment 1) Embodiments of the present invention described in claims 1 and 2 of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes an input image signal, and reference numeral 40 denotes a first portion for selecting a portion of the input image signal in which gradation display disturbance frequently occurs, such as a flat image region concentrated near a specific level. An area selection circuit 50, a second area selection circuit for selecting a portion of the input image signal where the gradation display disturbance is relatively infrequent, 60 a noise reduction circuit for reducing a noise component of the input signal, 9 Is a synthesizing circuit for synthesizing the outputs of the second area selecting circuit 50 and the noise reducing circuit 60. The synthesizing circuit 10 divides the signal of one field of the input signal into signals composed of a plurality of subfields, and performs gradation display. A subfield control circuit 11 for performing control is a plasma display panel.

In the embodiment of the present invention configured as described above, the image is divided into first and second regions by the first region selection circuit 40 and the second region selection circuit 50. The first area may be, for example, a part of a predetermined level range centered on each of the levels 64, 128, and 192 of the input image. The second area can be another part of the input signal. FIG. 2 shows this state.
2A illustrates an input image signal, FIG. 2B illustrates an output of the first area selection circuit 40, and FIG. 2C illustrates an output of the second area selection circuit 50. FIG. 2 showing the output of the first area selection circuit 40
The noise component of the signal shown in FIG. 2B is further removed by the noise reduction circuit 60, and becomes a signal having a constant value in a certain section as shown in FIG. 2D.

Next, the combining circuit 9 combines the signals shown in FIGS. 2C and 2D to obtain FIG. 2E. The output of the synthesizing circuit 9 is supplied to the plasma display panel 11 via the subfield control circuit 10.

In the conventional driving method using the subfield method, as shown in FIG. 11, for example, it has been found that gradation display disturbance at a specific input level is likely to occur.
With the above configuration, the input image extracts an image portion including a level at which gradation display disturbance is likely to occur, and selectively performs noise removal on this portion.
The probability that the signal level fluctuates near the gradation level at which the gradation display disturbance occurs decreases, and the frequency at which the gradation display disturbance occurs due to the noise component can be reduced.

As described above, in the plasma display panel according to the embodiment of the present invention, it is not necessary to control the order of the subfields constituting the subfield drive on a field-by-field basis. When the driving method using is used, 256
It is possible to reduce the occurrence of gradation display disturbance without sacrificing the gradation display characteristics of the driving method based on the original sub-field method, such as ensuring the gradation display. large.

(Embodiment 2) An embodiment of the invention described in claim 3 of the present invention will be described below with reference to the drawings. In FIG. 3, 1 is an input image signal, 2 is a motion detection circuit for detecting a motion area portion from the input image signal,
Is a motion area extraction circuit for extracting a motion area from an input image signal based on the detection result of the motion detection circuit 2, and 5 is a still image which similarly extracts a still image area from the input image signal based on the result of the motion detection circuit 2. A region extraction circuit, 6 is a low-pass filter (hereinafter referred to as LPF) for removing high-frequency components of the input signal, 9 is a synthesis circuit, 10 is a subfield control circuit,
Reference numeral 11 denotes a plasma display panel.

In the embodiment of the present invention configured as described above, portions different from the case of FIG. 1 will be mainly described. The input image signal 1 is subjected to motion detection using a motion detection circuit 2, and based on the detection result, a motion area extraction circuit 4
A moving image area consisting of a moving image portion,
The still image area extraction circuit 5 classifies the still image area into two areas of a still image area.

The high-frequency component is further removed by the LPF 6 from the image portion determined to be a motion image area. By the processing using the LPF 6, minute fluctuations in the amplitude direction are removed from the moving image area. FIG. 4 shows an example in which the input signal of the LPF 6 is shown in FIG.
The output waveform of No. 6 is shown in FIG.

As is clear from FIG. 4A, the number of times the level crosses the level at which the gradation display is likely to be disturbed, for example, between the level 127 and the level 128, can be significantly reduced by performing the LPF processing. . In the example of FIG. 4, the number of times of crossing between the level 127 and the level 128 was three before performing the filtering process, but is reduced to only one by performing the filtering process. The frequency of display disturbance can be reduced.

As described above, according to the present embodiment, first, motion detection is performed for a portion of the input image in a moving image region where gradation display disturbance is likely to occur, and the image signal of the selected region is thereby detected. The selective high-frequency component removal using LPF is performed. For this reason, first, it becomes possible to distinguish between the moving image region of the image and the still image region. By performing LPF processing on the detected motion image area, the image signal is flattened, and the number of times of passing through a signal level at which gradation display disturbance is likely to occur is reduced, and gradation display disturbance occurs. Frequency can be reduced. On the other hand, since unnecessary LPF processing is not performed on the still image area, the original information is displayed as it is, and the overall image quality of both the still image portion and the moving image portion can be improved.

(Embodiment 3) An embodiment of the invention described in claim 4 of the present invention will be described below with reference to the drawings. 5 is substantially different from the case of FIG. 3 in that a motion area enlarging circuit 3 is introduced.
Other points are almost the same. In the embodiment of the present invention configured as described above, a motion image area is detected from an input image by using a motion detection circuit 2 from an input image signal 1. The area is further enlarged by. FIG. 6 shows the concept of this region expansion.

FIGS. 6A and 6B show input image signals of the first field and the second field, respectively. A signal (c) representing an inter-field motion area is obtained from the difference between the two. Further, the moving area is expanded around the area by the moving area expanding circuit 3 to obtain an area as shown in FIG. The extent of this area expansion is set so that the motion detection result of the motion detection circuit 2 is expanded to the size of the area where the gradation display disturbance is likely to be perceived. For example, it is conceivable to enlarge the area so as to form a circle having a radius r (for example, the radius r is 30% of the height of the display device) around the area where the motion is detected.

The signal output from the moving area enlarging circuit 3 is input to a moving area extracting circuit, and as shown in the above-described embodiment, an area determined as a moving area is extracted. It is output after being removed.

As described above, in the plasma display panel according to the embodiment of the present invention, the movement area is extracted using the enlarged movement area as shown in FIG. Not only the part of the object but also a predetermined area around it can be extracted as a motion image area, and noise removal is also performed on this part.

For this reason, when the image is observed while following it,
The part in the background of the moving object will also be treated as a moving area, and it will be possible to suppress not only the moving image area but also the gradation display disturbance in the obstructive background part, and over a wider range It is possible to suppress gradation display disturbance.

(Embodiment 4) An embodiment of the invention described in claim 5 of the present invention will be described below with reference to the drawings. In FIG. 7, the difference from the case of FIG. 5 is substantially different from the case of FIG.
Is the point that has been introduced. In the embodiment of the present invention configured as described above, a portion different from the case of FIG. 5 will be mainly described.

The part extracted as a moving area in the moving area extracting circuit 4 from the input image signal 1 is a moving area in which so-called gradation display disturbance is likely to occur. As shown in FIG. 8 (a), the image signal of this portion often has noise superimposed on a normal natural image, and when a subfield driving method is used, a specific signal in which gradation display disorder is likely to occur. The number of times of crossing the level is relatively large even in the flat part of the signal.

Therefore, by using the area dividing circuit 61, in a portion where the amount of change of the signal is small, the signal is replaced with a representative value to create a constant area of the signal. For example, in FIG. 8B, the area is divided into three areas according to the representative value of the signal. In the driving method using the sub-field method, in a region where the input signal is a completely constant value, gradation display disturbance does not occur even in a moving image portion.
By performing such processing, the frequency of occurrence of gradation display disturbance can be significantly reduced.

As described above, according to the present embodiment, in the motion image area of the input image, an area having a small signal change amount is obtained by grouping the signals of the area with an appropriate representative value to obtain several flat areas. By dividing the area as a simple area,
The frequency of occurrence of gradation display disturbance can be significantly reduced.

(Embodiment 5) Embodiments of the present invention described in claims 6, 7 and 8 of the present invention will be described below with reference to the drawings. 9 differs from FIG. 5 in that a modulation signal generating circuit 7 and an adding circuit 8 are provided.

In the embodiment of the present invention configured as described above, the signal from the modulation signal generation circuit 7 is added as a modulation signal by the addition circuit 8 to the image of the noise-reduced motion area. In the modulation signal generation circuit 7, a modulation signal controlled by an area signal obtained by enlarging a motion amount and a motion area, which are outputs of the motion detection circuit 2, is generated. As this signal, for example, the signal shown in FIG. 10 can be considered.

FIG. 10A is an enlarged motion area signal obtained by enlarging the detected motion area, and FIG. 10B or FIG.
0 (c) is a modulation signal obtained from both the motion amount obtained by enlarging and the motion region obtained by enlarging, and “+ a” is applied only to a portion corresponding to the motion region obtained by enlarging. Alternatively, it is a signal having a level of “−a” (a is a predetermined numerical value of 1 or more and 255 or less), and the other portions are 0.
By the addition of the modulation signals, the pixel positions at which the gradation display disturbance occurs are displayed in a checkered pattern, so that the gradation display disturbance can be made inconspicuous. It is conceivable that the modulation signal is controlled as a different pattern depending on the magnitude of the motion amount. For example, when the motion amount per field is horizontally odd pixels (b), the motion amount per field is horizontally even pixels. In the case of (c), by controlling as shown in (c), the movement of the image is not synchronized with the position of the occurrence of the gradation disturbance, and the modulation signal added for the purpose of diffusing the place where the gradation display disturbance occurs becomes a line of sight. Can be prevented from being reduced due to the effect of the diffusion of the gradation display disturbance due to the overlap with the movement of the image.

As described above, according to the embodiment of the present invention, by reducing the noise component in the moving image area of the input image, the gradation of the part which is likely to be annoying when it occurs in the background part of the moving image or the like. Display disturbance can be suppressed. Furthermore, by performing a predetermined modulation operation such as amplitude modulation on the noise-reduced signal and displaying the signal, even if the gradation display disturbance remains and occurs, it becomes possible to disperse the gradation display. The display disturbance can be made more inconspicuous, and the frequency and degree of occurrence of gradation display disturbance can be significantly reduced in displaying an image using the subfield driving method.

(Embodiment 6) An embodiment according to a ninth aspect of the present invention will be described below with reference to the drawings. 11 is different from the case of FIG.
9 in that a variable delay circuit 80 is provided instead of the adder circuit 8 in FIG.

In the embodiment of the present invention configured as described above, similarly to the case of FIG. 9, the image of the motion area subjected to the noise reduction is converted by the variable delay circuit 80 into the modulated signal generating circuit 7. The delay time is controlled and output in accordance with the signal from. That is, the signal of the motion area is time-modulated by the output of the modulation signal generation circuit 7, is combined with the still image portion, and is supplied to the subfield control circuit and the plasma display panel. Since the portion where the display disturbance occurs is dispersed, there is an effect that the gradation display disturbance becomes inconspicuous. The form of the modulated signal is the same as in FIG.

As described above, according to the embodiment of the present invention, by reducing the noise component in the moving image area of the input image, the gradation of the part which is likely to be annoying when it occurs in the background part of the moving image or the like. Display disturbance can be suppressed. Further, by performing a predetermined modulation operation such as time-axis modulation on the noise-reduced signal and displaying the signal, it is possible to disperse the positions where the gradation display disturbance occurs, thereby making the gradation display disturbance less noticeable. Therefore, in displaying an image using the subfield driving method, the frequency and the degree of occurrence of gradation display disturbance can be significantly reduced.

[0051]

As described above, according to the image display device of the present invention, the following effects can be obtained.

According to the image display device of the present invention, the noise component is reduced in a predetermined portion of the input image, so that a signal which is extremely obstructive when the gradation display disturbance occurs is selectively flattened. Therefore, the frequency of occurrence of gradation display disturbance can be reduced. That is, according to the image display device of the first aspect of the present invention, it is not necessary to change the order of the subfields in a field unit or the like, so that the gradation display disturbance can be reduced. Further, since the light emission luminance weight of each subfield is not limited as in the above-described conventional example, the number of gray scales that can be displayed is not reduced, and it is extremely advantageous in that high image quality is secured. In addition, since the number of subfields is minimized, the driving pulse width can be secured and stable operation can be expected, and the effect is large in practical use.

According to the image display device of the present invention, the high-frequency component of the input image, in which the gradation display is likely to be disturbed, is selectively removed by the LPF. The signal is flattened, the frequency of occurrence of gradation display disturbance can be reduced, and the original gradation display characteristics can be secured in the still image portion.

According to the image display device of the fourth aspect of the present invention, not only the moving object itself, but also the background portion of the moving object is treated as a moving area. And the disturbance of gradation display that occurs in both cases can be suppressed. According to the image display device of the fifth aspect of the present invention, the frequency of occurrence of disturbance in gradation display is significantly reduced by integrating portions having only slight signal changes into several flat regions. Can be.

According to the image display device of the present invention, since the pixel positions where the gradation display disturbance occurs are displayed in a dispersed manner, the gradation display disturbance can be made inconspicuous.

In the embodiment of the present invention configured as described above, the image is divided into first and second areas by the first area selection circuit 40 and the second area selection circuit 50. The first area may be, for example, a part of a predetermined level range centered on each of the levels 64, 128, and 192 of the input image. The second area can be another part of the input signal. FIG. 2 shows this state.
2A illustrates an input image signal, FIG. 2B illustrates an output of the first area selection circuit 40, and FIG. 2C illustrates an output of the second area selection circuit 50. FIG. 2 showing the output of the first area selection circuit 40
The noise component of the signal shown in FIG. 2B is further removed by the noise reduction circuit 60, and becomes a signal having a constant value in a certain section as shown in FIG. 2D. The combining circuit 9 combines FIG. 2C and FIG. 2D to obtain FIG. The output of the synthesizing circuit 9 is
0, and is supplied to the plasma display panel 11.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image display device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation of region selection according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of an image display device according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating an operation of an LPF according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram of an image display device according to a third embodiment of the present invention.

FIG. 6 is a view for explaining processing of motion detection and motion area enlargement in Embodiment 3 of the present invention.

FIG. 7 is a configuration diagram of an image display device according to a fourth embodiment of the present invention.

FIG. 8 is a diagram illustrating area division according to a fourth embodiment of the present invention.

FIG. 9 is a configuration diagram of an image display device according to a fifth embodiment of the present invention.

FIG. 10 is a diagram illustrating a modulation operation according to the fifth embodiment of the present invention.

FIG. 11 is a configuration diagram of an image display device according to a sixth embodiment of the present invention.

FIG. 12 is a diagram showing an outline of a generation level of a gradation display disturbance by a conventional subfield driving method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input image signal 2 Motion detection circuit 3 Motion area enlargement circuit 4 Motion area extraction circuit 5 Still image area extraction circuit 7 Modulation signal generation circuit 8 Addition circuit 9 Synthesis circuit 10 Subfield control circuit 11 Plasma display panel 40 First area selection Circuit 50 Second region selection circuit 60 Noise reduction circuit 80 Variable delay circuit

Claims (9)

[Claims] 1. An image display device for displaying a multi-gradation display by dividing one field of an input image displayed on a display device into a plurality of sub-field images and displaying the divided image in a plurality of sub-fields. An image display device characterized in that a noise component is reduced and displayed. 2. The method according to claim 1, wherein the input image is divided into a predetermined first area and a second area.
Means for selecting an image in the area, means for reducing a noise component in the image in the area selected in the second area, and mixing the image selected in the first area and a signal in which the noise component is reduced. Means for outputting one of the output signals of the mixing means.
An image display device that divides a field portion into images of a plurality of subfields and displays the resulting image to perform multi-tone display. 3. The image display device according to claim 1, wherein the reduction of the noise component in a predetermined portion of the input image is a reduction of a high-frequency component in a motion image region of the input image. 4. The method according to claim 1, wherein the reduction of noise components in a predetermined portion of the input image is a reduction of noise components in a motion image region and a peripheral region of the input image.
The image display device as described in the above. 5. A method for reducing a noise component in a predetermined portion of an input image, wherein a part or all of an image region in a motion image region and a peripheral region of the input image is divided into regions divided by a certain level. 2. The image display device according to claim 1, wherein the image is an image. 6. An image display device for displaying a multi-gradation display by dividing one field of an input image displayed on a display device into a plurality of sub-field images and displaying the image in a multi-gradation display. An image display device, wherein after reducing the noise component, a signal obtained by reducing the noise component is subjected to a predetermined modulation operation and displayed. 7. The method according to claim 7, wherein the input image is formed by a predetermined first area and a second area.
Means for selecting an area, a means for reducing a noise component in an image of the area selected as the second area, and a modulation means for performing a predetermined modulation operation on a signal in which the noise component is reduced. Means for mixing the selected image and the output of the modulating means in the first area, and dividing one field of the output signal of the mixing means into a plurality of subfield images for display. An image display device that performs gradation display. 8. The image display device according to claim 7, wherein the modulation operation is an operation of adding a signal controlled based on a pixel position and an amount of motion of an image to a signal in which the noise component is reduced. 9. The image display according to claim 7, wherein the modulation operation is an operation for controlling a reading position of the signal in which the noise component is reduced by a signal controlled based on a pixel position and an amount of motion of an image. apparatus.