Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Nippon Hoso' Kyokai

Isao Kawahara

Kazuhiro Yamada

Kunio Sekimoto

Yuichi Ninomiya

Yoshimichi Ohtsuka

Hiromu Kitaura

Takayuki Kimoto

Yoshinori Izumi

Mitsuo Isobe

Masaki Tokoi

Yoshio Hirauchi

Tadashi Kawashima

Tomohisa Tagami

Toyokastu Koga

An image display apparatus for displaying gray-scale images by writing display information to an image display area of a panel. The display information includes values of a plurality of sub-fields that constitute one field. The image display apparatus converts an input image signal into a piece of display information so that a difference between sub-fields in correspondence with each other in adjacent high gray-scale levels becomes less. The image display apparatus displays a gray-scale image in accordance with the piece of display information.

Image display apparatus for writing display information with reduced electric consumption

An image display apparatus, such as a plasma display panel, suppresses dynamic false contours with gradation levels sufficiently retained. The image display apparatus has agitation constant adder for generating a plurality of agitation constants for a gradation level corresponding to an image signal, for selecting one agitation constant therefrom, and for adding the agitation constant to the image signal. As a result, dynamic false contours can not be visually perceived because their portions are dispersed by superimposing an agitation to each image signal.

Image display apparatus for correcting dynamic false contours

An image display apparatus using a display panel such as a plasma display panel having two illumination states aims to widen a dynamic range by increasing a ratio of maximum to minimum luminance reproducible on the same screen. In the image display apparatus, one TV field period is divided into a plurality of sub-fields which respectively have luminance weights and are arranged in order of time, and a gray-scale image is displayed by selecting a combination of sub-fields for each pixel and sustaining a light emission state of each pixel during the selected sub-fields, wherein when arranged in ascending order of luminance weight, the plurality of sub-fields include at least one sub-field whose luminance weight is one-half of a luminance weight of the next sub-field.

Image display apparatus

An Image correction device for detecting an image area having movement according to an image signal, and providing the image signal with image correction and switching correction methods according to a control signal. The image correction device further detects the boundary area of the image area having movement; detects an image area with great gradational change by comparing gradation of image signals corresponding to adjoining pixels; and provides the boundary area of the image area having movement with a diffusion process in an area excluding the image area with great gradational change. The correcting methods performed by the image correcting device can be switched according to the movement signal, thereby improving image correction.

Method and device of image correction

The gradation display device contains gradient detecting circuit () for detecting a gradient of gradation values of pixels in an incoming image; time-varying gradation-value detecting circuit () for detecting changes in gradation values of the pixels with a passage of time; an image detector for detecting a magnitude and a direction of movement of the incoming image according to outputs from gradient detecting circuit () and time-varying gradation-value detecting circuit (); and gradation correcting circuit () for correcting signals of the incoming image according to the detected magnitude and direction of the image and the weight of luminance assigned to each of the sub-fields so as to display proper image.

Gradation display device

The image display device disclosed detects areas including grayscales with gradients and motions in an image signal and compensates the prescribed grayscales of the image signals to the other grayscales according to the motion amplitude and direction of the area, and the gradient amplitude and direction of the grayscale. Consequently, intermediate non-lit sub-fields causing the dynamic false contour are distributed to display image suppressing the dynamic false contour.

Image display device

The present invention provides a gray scale display method and apparatus that can be used with a large screen plasma display panel to perform illumination in a binary manner while substantially controlling flicker effects. The gray scale can be displayed by combining illumination and non-illumination periods in each of a plurality of subfields, the subfields being defined by at least a first block and a second block which have different structures. The plurality of subfields are arranged so that the luminance value of each subfield is in an ascending or descending order in the blocks.

Gradation display method capable of effectively decreasing flickers and gradation display

Image display

In an image display device equipped with a panel having first and second electrodes, a field period is divided into a plurality of sub-field periods that each have a predetermined luminance weight, and a gray-scale image for is displayed by (a) writing sub-field image data of each sub-field period obtained by dividing input image data of the field period into the plurality of sub-field periods, into the panel through the first and second electrodes, and (b) sustaining an illumination state of ON or OFF in each cell for each sub-field period using luminance equivalent to a luminance weight of each sub-field period. The image display device includes an image changing unit for changing a part of sub-field image data of a predetermined sub-field period, so that a total number of charges and discharges performed on the first electrode when writing the sub-field image data becomes smaller.

Gray-scale image display device that can reduce power consumption when writing data

A multilevel image display method performs error diffusion processing on data that is inputted as multiphase data. The display error of a target pixel is diffused into pixels included in data blocks that are inputted after the data block that includes the target pixel.

Multilevel image display method

An image display apparatus which displays images, suppressing the occurrence of the moving image false edge. The image display apparatus selects a signal level among a plurality of signal levels in accordance with a motion amount of an input image signal, where each signal level is expressed by an arbitrary combination of 0, W1, W2, . . . and WN and luminance weights W1, W2, . . . and WN are assigned to subfields.

Image display apparatus and image evaluation apparatus

There is provided a low-cost scanning line converting circuit being capable of properly converting the number of scanning lines for a video signal at various conversion ratios. Under the control of a write control signal generating circuit, an original video signal is written, on a scanning-line basis, in individual line memories. A write operation is performed to each of the line memories based on a clock and a horizontal synchronizing signal on the input side, while a read operation is performed to each of the line memories based on a clock and a horizontal synchronizing signal on the output side. A selecting circuit selects, based on a line select signal, at least one from scanning line signals stored in the individual line memories necessary to generate a post-conversion scanning line signal and outputting the selected scanning line signal. Coefficient multipliers multiply the scanning line signal selectively outputted by interpolation coefficients (1&minus;k) and k and an adder adds up the results of multiplication to output the sum as the post-conversion scanning line signal. A coefficient control circuit and a dividing circuit are capable of generating a coefficient direct signal k in accordance with a ratio for converting the number of signal lines.

Scanning line converting circuit and interpolation coefficient generating circuit

An image display apparatus which displays images, suppressing the occurrence of the moving image false edge. The image display apparatus selects a signal level among a plurality of signal levels in accordance with a motion amount of an input image signal, where each signal level is expressed by an arbitrary combination of 0, W,W,. . . and WN and luminance weights W,W,. . . and WN are assigned to subfields.

An image display apparatus is provided for reducing occurrences of moving image false-edges by preventing profound changes in &ldquo;on&rdquo;/&ldquo;off&rdquo; subfield distribution, and for displaying a sharp image that does not appear blurred. This is achieved by effectively dividing one TV field and by displaying a gray level of an input image signal using an &ldquo;on&rdquo;/&ldquo;off&rdquo; subfield combination, out of possible &ldquo;on&rdquo;/&ldquo;off&rdquo; subfield combinations for displaying the gray level, in which a number of subfields with large luminance weightings that are &ldquo;on&rdquo; is minimized.

Image display apparatus with selected combinations of subfields displayed for a gray level

A plasma display having a quartet type pixel structure provides a high grade and excellent picture quality picture and maintains good white balance and excellent intensity levels. The plasma display comprises a reference circuit .phi. for outputting a control signal based on the least significant bit of a digitized green video signal and a timing signal and an arithmetic circuit 8 for performing an arithmetic operation on the output of the reference circuit. As a result of this arrangement, the least significant bit information, that was lost by halving the green signal value to maintain the white balance is incorporated in the halved green signal based on a timing signal, thereby realizing 256 intensity levels without degrading the halftone in the video picture.

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Osaka, Japan

Isao Kawahara