Patent ID: 6256417
Filing Date: 2001-07-03
Classification: H04N

Abstract:
An image coding apparatus for coding an input signal comprising an image signal being an array of pixels having pixel values, and a significant signal showing whether the image signal is significant or not, said apparatus comprising:prediction image generating means for specifying, as a target area, an area of the input image signal to be the target of coding, on the basis of the input significant signal, and generating a prediction image for the target area, using a locally reproduced image which is described later;subtraction means for dividing the prediction image into a plurality of small prediction areas, dividing the target area into a plurality of small target areas, subtracting each small prediction area from corresponding small target area, and outputting a differential signal;first area dividing means for dividing a rectangle area including significant pixels from the differential signal in a first direction using the significant signal, and outputting the rectangle area as a first significant area;pixel generating means for generating a padding pixel value using a prescribed first function on the basis of pixel values of the significant pixels in the first significant area, replacing pixel values of insignificant pixels in the significant area with the padding pixel value, and outputting a padded signal;first coding means for coding the padded signal and outputting a first coded signal;second area dividing means for dividing an area from the first coded signal in a second direction different from the first direction, and outputting the area as a second significant area;padding component generating means for generating a padding coded component using a second function on the basis of coded components of the first coded signal when the coded components of the first coded signal do not exist in the second significant area, replacing coded components which are not the coded components of the first coded signal in the second significant area, with the padding coded component, and outputting a padded coded signal;second coding means for coding the padded coded signal and outputting a second coded signal;decoding means for decoding the second coded signal and outputting a decoded signal;addition means for adding the decoded signal and the prediction image to generate a locally reproduced image; andstorage means for temporality storing the locally reproduced image for use in the prediction image generating means.