Image Processor, Image Processing Method, Image Encoder, Image Encoding Method, and Image Display Device
AssigneeMitsubishi Electric Corporation
InventorsNoritaka Okuda, Jun Someya, Hideki Yoshii
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Abstract
In the image processors and the image processing methods of the present invention, the number of bits for quantizing image data is adjusted on the basis of a dynamic range of each block. Therefore, the error introduced by encoding is reduced without increasing the data amount of the encoded image data, and the response speed of a liquid crystal can be controlled appropriately by preventing unnecessary voltages from being applied due to the error introduced by encoding.
Claims17
An image processor that outputs image data representing a gray-scale value of each image pixel corresponding to a voltage applied to a liquid crystal, so as to correct the gray-scale value on the basis of a change of the gray-scale value, the image processor comprising:
- an encoding means for quantizing image data of a current frame on a block basis and outputting encoded image data corresponding to the current frame image;
- a first decoding means for decoding the encoded image data outputted from the encoding means thereby outputting first decoded image data corresponding to the current frame image data;
- a delaying means for delaying the encoded image data outputted from the encoding means by a period equivalent to one frame;
- a second decoding means for decoding the encoded image data outputted from the delaying means, thereby outputting second decoded image data corresponding to image data preceding the current frame by one frame;
- a variation calculating means for calculating a variation between the first decoded image data and the second decoded image data for each pixel;
- a one-frame-preceding image calculating means for calculating reproduced image data corresponding to the image data preceding the current frame by one frame, using the variation and the current frame image data;
- and
- a compensating means for correcting the gray-scale value of the current frame image based on the current frame image data and the reproduced image data;
- wherein the encoding means adjusts the number of bits for quantizing the image data in each block of the current frame based on a dynamic range of image data in each block of the current frame.
An image processing method that outputs image data representing a gray-scale value of each image pixel corresponding to a voltage applied to a liquid crystal, so as to correct the gray-scale value on the basis of its change, the method comprising the steps of:
- quantizing image data of a current frame on a block basis and outputting encoded image data corresponding to the current frame image;
- decoding the encoded image data outputted from the encoding means thereby outputting first decoded image data corresponding to the current frame image data;
- delaying the encoded image data outputted from the encoding means by a period equivalent to one frame;
- decoding the encoded image data outputted from the delaying means thereby outputting second decoded image data corresponding to image data preceding the current frame by one frame;
- calculating a variation between the first encoded image data and the second encoded image data for each pixel;
- calculating reproduced image data corresponding to the image data preceding the current frame by one frame, using the variation and the current frame image data;
- and
- correcting the gray-scale value of the current frame image based on the current frame image data and the reproduced image data;
- wherein the number of bits for quantizing image data in each block of the current frame is adjusted based on a dynamic range of the image data in each block of the current frame.
An image encoder, comprising:
- an image-data dividing means for diving image data into image data blocks thereby outputting block image data;
- a dynamic range producing means for detecting a dynamic range of the block image data thereby outputting dynamic range data;
- an average calculating means for calculating an average of the block image data thereby outputting average data;
- a quantizing means for quantizing the block image data, using a quantization threshold value determined by the dynamic range data and the average data, thereby outputting quantization image data;
- and
- an encoded data combining means for generating encoded image data corresponding to the block image data, from the quantization image data, the dynamic range data, and the average data;
- wherein the quantizing means adjusts the number of bits for quantizing the block image data, depending on the dynamic range of the block image data.
An image encoding method, comprising the steps of:
- dividing image data into image data blocks thereby outputting block image data;
- detecting a dynamic range of the block image data thereby outputting dynamic range data;
- calculating an average of the block image data thereby outputting average data;
- quantizing the block image data, using a quantization threshold value determined by the dynamic range data and the average data, thereby outputting quantization image data;
- and
- generating encoded image data corresponding to the block image data, from the quantization image data, the dynamic range data, and the average data;
- wherein the number of bits for quantizing the block image data is adjusted depending on the dynamic range of the block image data.
Dependencies are inferred from the claim text.