Linear phase orthonormal filter banks

Paraunitary systems in which each individual filter in the analysis and synthesis banks has linear phase are studied. This property is often desirable for several applications, particularly in image processing. Several theoretical questions pertaining to linear phase paraunitary systems are answered. Next, a factorization for such systems is developed which is proved to be minimal as well as complete. The number of parameters in the optimization process is reduced by structurally imposing the additional condition that the filters satisfy pairwise mirror-image symmetry in the frequency domain. Examples of M-band linear phase orthonormal wavelets are presented.<>