Patent ID: 8588540
Filing Date: 2013-11-19
Classification: H03M,H04N

Abstract:
1. A coding apparatus, using arithmetic coding, which generates binary data indicating a value of decimal place in a range greater than or equal to “0” and less than “1” as coded data, and outputs the coded data, comprising: an image data input unit to input image data; a frequency conversion unit to perform frequency conversion on the inputted image data; a quantization unit to quantize coefficient data which is frequency-converted by said frequency conversion unit; a binarization unit to binarize the coefficient data quantized by said quantization unit and output a binary symbol; a range dividing and selection unit to, upon each input of the binary symbol, repeat dividing of a range represented with finite precision into two ranges in accordance with a ratio between occurrence probabilities of MPS (More Probable Symbol) and LPS (Less Probable Symbol) and selection of one of the two ranges; a normalization unit to, when a length of the range selected by said range dividing and selection unit is less than a predetermined range length, perform normalization so as to increase the size of said selected range; a detection unit to detect an upper limit and a lower limit of the range to be normalized; and a reserved bit processing unit to, in a case that a value of the lower limit of the range to be normalized is less than a predetermined criterion and a value of the upper limit of the range to be normalized is not less than the predetermined criterion, determine that a value of digit of interest is unknown at this time, and, if it is determined that the value of the digit of interest is unknown at this time, increment a value of reserved bits.