Matlab implementation of the multiresolution Gabor filters in 1 and 2 dimensions.
filters(M, alpha, tau, flag)
function [H, G] = filters(M, alpha, tau, flag)
%
% sets up the multiresolution spline filters.
% H is the lowpass filter, G is the highpass filter
% flag = 1 (analysis), and = 0 (synthesis)
%
%
nu = (0: 1: M - 1) / M;
p = 0.5*(alpha+1) - tau;
q = 0.5*(alpha+1) + tau;
[A, A2] = autocorr(M, alpha);
H = sqrt(2) * ( (1+exp(2*sqrt(-1)*pi*nu))/2 ).^p .* ...
( (1+exp(-2*sqrt(-1)*pi*nu))/2 ).^q;
G = exp(2*sqrt(-1)*pi*nu) .* A .* H;
G = conj( [G(M/2+(1:M/2)) G(1:M/2)] );
if flag == 1
return;
else
H = (H .* A) ./ A2;
G = G ./(A2 .* [A(M/2+(1:M/2)) A(1:M/2)]);
end