Patent ID: 7454064
Filing Date: 2008-11-18
Classification: G06T

Abstract:
1. An image data coder for coding multivalued image data in which a value of each pixel is expressed by a plurality of bits, comprising: a reading unit operable to read the multivalued image data per predetermined number of pixels; a generating unit operable to generate, from the values of each read plurality of pixels, fixed-length gradation characteristic data expressing a gradation characteristic of the pixels, and fixed-length quantized data obtained by quantizing each pixel value into a plurality of bits using a predetermined threshold value; a dividing unit operable to divide the generated data into the gradation characteristic data, and pieces of bit data each formed from bits in a same position of bit strings, in the quantized data, corresponding one-to-one with the pixels; and a coding unit operable to entropy code at least part of the divided data.