Patent ID: 7242814

Claim:
An apparatus for decoding an encoded signal and transforming the decoded signal in compliance with a transformation rule to reproduce an image signal, comprising: a first unit that derives a transformation base that forms said transformation rule based on the decoded signal; and a second unit that transforms the decoded signal in compliance with said transformation rule based on the derived transformation base to reproduce said image signal, wherein said first unit further comprises a base selecting unit that selects a transformation base to be used by said second unit from a plurality of predetermined transformation bases based on a characteristic of said reference signal, said base selecting unit obtains a relationship between each of said plurality of transformation bases and the characteristic of signal value distribution of said reference signal, and selects a transformation base, the relationship of which with the characteristic of signal distribution of said reference signal; said encoded signal is an encoded image signal in connection with an image; said base selecting unit obtains a similarity relationship between a base vector indicating said characteristic and said characteristic of signal value distribution of said reference signal for each one of said plurality of transformation base.