Design of generalized filter banks with unequal-length and its application of image coding
In this paper, we present a design and implementation of the M-channel linear-phase filter banks with unequal-length and same center of symmetry. The filter banks are separated into paraunitary and biorthogonal case. We discuss both cases. A novel filter bank can be regarded as a special class of generalized lapped transform with arbitrary number of channels M. In image coding applications, long basis functions should be used to avoid the blocking artifacts in low-frequency bands, while short basis functions should be used to reduce the ringing artifacts in high-frequency bands. Having the same center of symmetry is suitable for progressive image coder [SPIHT] [10]. Filter banks with such characteristics can be achieved structurally by taking acount of the lattice structure. Finally, several design and image coding examples are shown.
filter banks image coding lapped transforms