www.pudn.com > nsct_toolbox.rar > parafilters.m, change:2004-08-07,size:1552b

function [y1, y2] = parafilters( f1, f2 ) % PARAFILTERS Generate four groups of parallelogram filters. % PARAFILTERS generates four groups of parallelogram filters from a pair of % diamond filters F1 and F2 by modulation and rotation operations. % % parafilters( f1, f2 ) % % INPUT: % f1: % a matrix, the filter for the first branch. % f2: % a matrix, the filter for the second branch. % % OUTPUT: % y1: % a cell vector of matrices, four outputs for the first branch. % y2: % a cell vector of matrices, four outputs for the second branch. % % NOTE: % Refer to pp. 51, Minh N. Do's thesis. % % History: % 08/06/2004 Created by Jianping Zhou. % % See also: MODULATE2, RESAMPZ. % Initialize output y1 = cell(1, 4); y2 = cell(1, 4); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Obtain fan filters from the diamond filters %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Modulation operation y1{1} = modulate2(f1, 'r'); y2{1} = modulate2(f2, 'r'); y1{2} = modulate2(f1, 'c'); y2{2} = modulate2(f2, 'c'); % Transpose operation y1{3} = y1{1}'; y2{3} = y2{1}'; y1{4} = y1{2}'; y2{4} = y2{2}'; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Obtain parallelogram filters from the fan filters % Use the rotation sampling matrices. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% for i = 1:4 % Resample the filters by corresponding rotation matrices y1{i} = resampz( y1{i}, i ) ; y2{i} = resampz( y2{i}, i ) ; end