Edge-based subband image coding technique for encoding the upper-frequency bands
Nader Mohsenian, Nasser M. Nasrabadi · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1991
A subband coding (SBC) scheme, exploiting the dependencies that exist across the bands, is developed which can effectively compress the upper frequency bands of the decomposed image. An edge-detecting filter is incorporated into the SBC model that extracts the edge-pixels in the base-band, and identifies the locations of their counterparts in the upper-bands accordingly without transmission of any overhead information. A memoryless vector quantizing (VQ) scheme was used to encode the base-band: Once the edge-detected reconstructed base-band became available, another VQ coding scheme was employed to encode the upper frequency components across the bands in conjunction with the error derived due to the decoded base-band, only at edge locations. High quality 512 x 512 images were reconstructed at ~ 0.7 bits/pixel.