Practical nonunitary filter banks for subband coding of images
T.A. Ramstad, E. Saltnes, S.O. Aase · 2002
The paper presents a filter bank for subband image coding which has a number of nice properties including simple implementation, high coding gain, no blocking effects, and limited ringing. All these properties can be obtained only because the filter bank is nonunitary and can be optimized for different task in the encoder and the decoder. The complexity is minimized in the decoder filter bank by forcing it into a form where most channels are equal to the channels in the standard cosine transform.>