IMAGE CODING METHOD, IMAGE CODING APPARATUS, AND IMAGING SYSTEM

摘要

The image coding method according to the present invention includes the following steps. At a histogram calculation step, a histogram of pixel values included in a block image is calculated. At a plane region detection step, a size of a plane region included in the block image is detected. At an orthogonal transformation size selection step, (i) a first processing size is selected as a processing size of orthogonal transformation for the block image when the histogram is bimodal and the size of the plane region is equal to or greater than the first threshold value, and (ii) a second processing size greater than the first processing size is selected as the processing size, when that the histogram is not bimodal or the size of the plane region is smaller than the first threshold value.