Patent ID: 6658155
Filing Date: 2003-12-02
Classification: H04N

Abstract:
An image-signal conversion apparatus for converting an original-image signal to an output-image signal having a smaller amount of information than the original-image signal, comprising:intermediate-image-signal generation means for generating an intermediate-image signal having the same amount of information as the output-image signal, from the original-image signal; intermediate-image storage means for storing the pixel value of each pixel of the intermediate-image signal, the pixel value being linked to each class code; prediction-coefficient storage means for storing a prediction coefficient linked to each class code; prediction-coefficient update means for generating, according to the intermediate-image signal, the class code linked to an aimed-at pixel in the intermediate-image signal, and the original-image signal, a more-appropriate prediction coefficient linked to the class code, and for updating the prediction coefficient linked to each class code, stored in said prediction-coefficient storage means; class-code update means for selecting a more appropriate class code linked to the aimed-at pixel in the intermediate-image signal, according to the intermediate-image signal, the prediction coefficient linked to the class code linked to the pixel value of the aimed-at pixel in the intermediate-image signal, and the original-image signal, and for updating the class code linked to the pixel value of the aimed-at pixel in the intermediate-image signal, stored in said intermediate-image storage means; and determination means for determining the intermediate-image signal as the output-image signal when a predetermined condition is satisfied.