Linear-phase paraunitary filter banks with unequal length

We present a design and implementation of M-channel linear-phase paraunitary filter banks (LPPUFB) with unequal length filters and same center points. Our main motivation is the application in effective image coding. For low-frequency signals, long basis functions should be used to avoid the blocking effect. While, short basis functions should be used to reduce the ringing noise for high-frequency signals. LPPUFB with such characteristics can be achieved structurally by taking account of the lattice structure. Finally some design examples are shown.