Image encoding/decoding devices and image band decomposing/composing devices

摘要

A down-sampler samples down a signal whose low frequency component is cut to 1/2. A sign inversion unit cyclically multiplies the sampled-down high-frequency sub-band signal by a negative value and outputs a sign-inverted high-frequency sub-band signal. Thus, in the frequency characteristic of the high-frequency sub-band signal, the signal power on the low frequency side can be increased.