www.gusucode.com > 基于matlab编程Contourlet变换在图像检索源码程序 > code1/基于matlab编程Contourlet变换在图像检索源码程序/code/nsct_toolbox/ldfilter.m
function f = ldfilter(fname) % LDFILTER Generate filter for the ladder structure network % % f = ldfilter(fname) % % Input: % fname: Available 'fname' are: % 'pkvaN': length N filter from Phoong, Kim, Vaidyanathan and Ansari switch fname case {'pkva12', 'pkva'} v = [0.6300 -0.1930 0.0972 -0.0526 0.0272 -0.0144]; case {'pkva8'} v = [0.6302 -0.1924 0.0930 -0.0403]; case {'pkva6'} v = [0.6261 -0.1794 0.0688]; otherwise error('Unrecognized ladder structure filter name'); end % Symmetric impulse response f = [v(end:-1:1), v];