关键词: 两通道图滤波器组, 正交, 迭代算法, 重构误差

Abstract:

An iterative algorithm based on second-order approximation of Taylor's series is proposed to overcome the problem that the two channel orthogonal graph filter bank possesses poor frequency characteristic.First, the design problem is formulated into a constrained optimization problem, whose objective function is the reconstruction error of the two channel orthogonal graph filter bank, and the constraint function is the stopband attenuation.Then, by means of the Taylor approximation, the highly nonlinear nonconvex objective function is approximately transformed into a convex quadratic function with respect to increments. Thus, the nonconvex optimization problem is approximated to a convex optimization problem.Finally, an iterative technique is used to solve the optimization problem.Simulation results show that the reconstruction error of the two channel orthogonal graph filter bank obtained by the new method is approximately one order of magnitude lower than that by the Bernstein polynomial approximation algorithm and that the improvement on the reconstruction error is about 8dB.

Key words: two-channel graph filter bank, orthogonality, iterative technique, reconstruction error