Patent ID: 8265402

Claim:
An encoding device comprising: two-dimensional Haar wavelet transforming means for dividing each two-dimensional signal into a plurality of subbands represented by a set of predetermined number of coefficients; coefficient extracting means for, whenever said two-dimensional Haar wavelet transforming means transforms a predetermined number of said two-dimensional signals, extracting sets of AC-component coefficients from each of said set of predetermined number of coefficients, for every predetermined number of said set of predetermined number of coefficients which belong to the same spatial position; coefficient encoding means for encoding and concatenating the extracted AC-component coefficient sets, and generating a code sequence of a high-frequency subband; initial coefficient encoding means for encoding a DC-component as a lowest-frequency subband, and generating a code sequence of the lowest-frequency subband; code output means for outputting the code sequence of the lowest-frequency subband, and sequentially outputting the code sequence of the high-frequency subband generated by said coefficient encoding means; coefficient thinning map generating means for generating a coefficient thinning map in which a resolution at each spatial coordinate of the two-dimensional signal is set, and updated region detecting means for detecting an updated region from a plurality of sequential frames forming the two-dimensional signal, and obtaining a changing period during which a signal value changes in each region from said plurality of sequential frames, wherein said coefficient thinning map generating means sets the resolution on the basis of the changing period, and generates a coefficient thinning map in which resolution of the updated region differs from resolution of a region other than the updated region, and said coefficient extracting means refers to the coefficient thinning map, and extracts coefficients by thinning the AC-component coefficients to the resolution set for the spatial coordinate.