2–D Lossless FIR Filter Design Using Synthesis of the Paraunitary Transfer Function Matrix

A synthesis method for designing two-dimensional lossless finite impulse response (FIR) filters for various digital signal processing tasks is proposed. The synthesis method is based on using a 2-D embedding approach to obtain the paraunitary transfer function matrix of the lossless FIR filter. The elements of the paraunitary transfer function matrix are the transfer function of a given lossy FIR structure and the transfer functions for its complementary structures. The embedding method is used to design complementary FIR filter structures for several known lossy FIR filters. The lossless FIR filter matrix obtained in this article has a size of 3 × 1 and satisfies the paraunitary conditions. The conditions are described by a set of nonlinear equations. A modified Newton method is used to solve this set of equations. The proposed design method is used to determine the lossless structures of two-dimensional FIR filters for various digital processing tasks.