www.pudn.com > 666bandelets_toolbox.zip > compute_quadrant_selection.m

function [selx,sely] = compute_quadrant_selection(j,q) 
 
% compute_quadrant_selection - compute the indice 
%   for selecting a given quadrant at a given scale 
%   of a wavelet transform. 
% 
%   q=1 is for phi/psi (on X / on Y) 
%   q=2 is for psi/phi (on X / on Y) 
%   q=3 is for psi/psi (on X / on Y) 
% 
%   % Suppose that MW contains a wavelet transform  
%   j = 4; q = 2; 
%   [selx,sely] = compute_quadrant_selection(j,q); 
%   MWs = MW(selx,sely);    % MWs contains the quadrant. 
% 
%   Copyright (c) 2004 Gabriel Peyré 
 
if q<0 || q>3 
    error('Quadrant number is in {0,1,2,3}.'); 
end 
 
if q==0 
    selx = 1:2^j; 
    sely = 1:2^j; 
elseif q==1 % 1st quadrant 
    selx = 1:2^j; 
    sely = (2^j+1):2^(j+1); 
elseif q==2 
    selx = (2^j+1):2^(j+1); 
    sely = 1:2^j; 
else 
    selx = (2^j+1):2^(j+1); 
    sely = (2^j+1):2^(j+1); 
end