GENERALIZED LAPPED BIORTHOGONAL TRANSFORM EMBEDDED INVERSE DISCRETE COSINE TRANSFORM AND LOW BIT RATE VIDEO SEQUENCE CODING ARTIFACT REMOVAL

摘要

A generalized lapped biorthogonal transform embedded inverse discrete cosine transform (ge-IDCT) (20), as an alternative to the inverse discrete cosine transform (IDCT) within a system for still image compression. The ge-IDCT (20) takes advantage of the DCT (18) front end of the generalized lapped biorthogonal transform (GLBT) in inverse transforming the DCT (18) coefficients. Non-linear weighting is used in the embedded lapped transform domain (16), so that the ge-IDCT (20) can reconstruct the signal with alleviated blockishness. In another embodiment, the disclosed system includes a post-processing method to reduce anomalies caused by blocking artifacts by applying a lapped orthogonal transform-embedded inverse discrete cosine transform (le-IDCT), as a substitute for the usual inverse DCT (18). For the reduction of ringing artifacts, a nonlinear robust filter is applied to the decoded picture frame.