Lifting coefficient conversion device and lifting coefficient conversion method

摘要

PPROBLEM TO BE SOLVED: To provide a lifting coefficient transforming method and lifting coefficient transforming apparatus capable of highly accurately calculating an integral lifting coefficient capable of avoiding checkerboard distortion or the like with relatively low bit precision. PSOLUTION: A lifting coefficient transforming apparatus 90 transforms, from a real coefficient to a fractionally represented integral lifting coefficient, a lifting coefficient used in lifting configurations of a demultiplexing-side filter and a multiplexing-side filter achieving discrete wavelet transform for image compression and discrete inverse wavelet transform for decoding a compressed image. A degree determination means 91 determines a degree M for a denominator of a transformed integral lifting coefficient N/2SPM/SP(N, M: integers of ≥1). Within a search range determined by a search range determining means 92, a numerator N of the integral lifting coefficient is searched so as to minimize a differential absolute value between an absolute value of the total sum of even-numbered coefficients and an absolute value of the total sum of odd-numbered coefficients among filter coefficients of the multiplexing-side filter composed of the integral lifting coefficient. PCOPYRIGHT: (C)2007,JPO&INPIT