www.gusucode.com > 指纹识别源代码 > 指纹识别源代码/指纹识别的matlab源码/conv2fft.m
function [out] = conv2fft(z1,z2,shape,shape2)
%CONV2FFT FFT-based two dimensional convolution.
% C = CONV2FFT(A, B) performs the 2-D convolution of matrices
% A and B. If [ma,na] = size(A) and [mb,nb] = size(B), then
% size(C) = [ma+mb-1,na+nb-1].
% C = CONV2FFT(H1, H2, A) convolves A first with the vector H1
% along the rows and then with the vector H2 along the columns.
%
% C = CONV2FFT( ... ,'shape') returns a subsection of the 2-D
% convolution with size specified by 'shape':
% 'full' - (default) returns the full 2-D convolution,
% 'same' - returns the central part of the convolution
% that is the same size as A.
% 'valid' - returns only those parts of the convolution
% that are computed without the zero-padded
% edges. size(C) = [ma-mb+1,na-nb+1] when
% all(size(A) >= size(B)), otherwise C is empty.
%
%
% Please contribute if you find this software useful.
% Report bugs to luigi.rosa@tiscali.it
%
%*****************************************************************
% Luigi Rosa
% Via Centrale 27
% 67042 Civita di Bagno
% L'Aquila --- ITALY
% email luigi.rosa@tiscali.it
% mobile +39 340 3463208
% http://utenti.lycos.it/matlab
%*****************************************************************
%
%--------------------------------------------------------------------------
%--------------------------------------------------------------------------
% 3 input arguments: matrix 1, matrix 2, shape
if ((nargin==3)&&(isa(shape,'char')))
if strcmp(shape,'same')
z1x=size(z1,1);
z1y=size(z1,2);
z2x=size(z2,1);
z2y=size(z2,2);
if any(any(imag(z1)))||any(any(imag(z2)))
out=(ifft2(fft2(z1,z1x+z2x-1,z1y+z2y-1).*fft2(z2,z1x+z2x-1,z1y+z2y-1)));
else
out=real(ifft2(fft2(z1,z1x+z2x-1,z1y+z2y-1).*fft2(z2,z1x+z2x-1,z1y+z2y-1)));
end
px=((z2x-1)+mod((z2x-1),2))/2;
py=((z2y-1)+mod((z2y-1),2))/2;
out=out(px+1:px+z1x,py+1:py+z1y);
return;
end
if strcmp(shape,'full')
z1x=size(z1,1);
z1y=size(z1,2);
z2x=size(z2,1);
z2y=size(z2,2);
if any(any(imag(z1)))||any(any(imag(z2)))
out=(ifft2(fft2(z1,z1x+z2x-1,z1y+z2y-1).*fft2(z2,z1x+z2x-1,z1y+z2y-1)));
else
out=real(ifft2(fft2(z1,z1x+z2x-1,z1y+z2y-1).*fft2(z2,z1x+z2x-1,z1y+z2y-1)));
end
return;
end
if strcmp(shape,'valid')
z1x=size(z1,1);
z1y=size(z1,2);
z2x=size(z2,1);
z2y=size(z2,2);
if ((z1x<z2x)||(z1y<z2y))
out=[];
return;
else
end
if any(any(imag(z1)))||any(any(imag(z2)))
out=(ifft2(fft2(z1,z1x+z2x-1,z1y+z2y-1).*fft2(z2,z1x+z2x-1,z1y+z2y-1)));
else
out=real(ifft2(fft2(z1,z1x+z2x-1,z1y+z2y-1).*fft2(z2,z1x+z2x-1,z1y+z2y-1)));
end
px=z2x;
py=z2y;
out=out(px:px+z1x-z2x,py:py+z1y-z2y);
return;
end
end
%--------------------------------------------------------------------------
%--------------------------------------------------------------------------
% 2 input argiments: matrix 1, matrix 2, by default shape is 'full'
if (nargin==2)
z1x=size(z1,1);
z1y=size(z1,2);
z2x=size(z2,1);
z2y=size(z2,2);
if any(any(imag(z1)))||any(any(imag(z2)))
out=(ifft2(fft2(z1,z1x+z2x-1,z1y+z2y-1).*fft2(z2,z1x+z2x-1,z1y+z2y-1)));
else
out=real(ifft2(fft2(z1,z1x+z2x-1,z1y+z2y-1).*fft2(z2,z1x+z2x-1,z1y+z2y-1)));
end
return;
end
%--------------------------------------------------------------------------
%--------------------------------------------------------------------------
% conv2(c,r,a) where c and r are arrays, a is a matrix
if (isa(shape,'double'))
%--------------------------
% by default shape is 'full'
if (nargin==3)
a=shape;
c=z1;
r=z2;
[ax,ay]=size(a);
[rx,ry]=size(r);
[cx,cy]=size(c);
if size(convfft(a(1,:),r),1)==1
for ii=1:ax
y2(ii,:)=convfft(a(ii,:),r);
end
else
for ii=1:ax
y2(ii,:)=convfft(a(ii,:),r)';
end
end
[y2x,y2y]=size(y2);
if size(convfft(y2(:,1),c),1)==1
for ii=1:y2y
y3(:,ii)=convfft(y2(:,ii),c)';
end
else
for ii=1:y2y
y3(:,ii)=convfft(y2(:,ii),c);
end
end
out=y3;
return;
end
%-------------------------
if (nargin==4)
a=shape;
c=z1;
r=z2;
[ax,ay]=size(a);
[rx,ry]=size(r);
[cx,cy]=size(c);
if cx==1
dimx=cy;
else
dimx=cx;
end
if rx==1
dimy=ry;
else
dimy=rx;
end
if size(convfft(a(1,:),r),1)==1
for ii=1:ax
y2(ii,:)=convfft(a(ii,:),r);
end
else
for ii=1:ax
y2(ii,:)=convfft(a(ii,:),r)';
end
end
[y2x,y2y]=size(y2);
if size(convfft(y2(:,1),c),1)==1
for ii=1:y2y
y3(:,ii)=convfft(y2(:,ii),c)';
end
else
for ii=1:y2y
y3(:,ii)=convfft(y2(:,ii),c);
end
end
out=y3;
[outx,outy]=size(out);
%---------------------------------------------
if strcmp(shape2,'full')
return;
end
%---------------------------------------------
if strcmp(shape2,'valid')
lx=ax-dimx+1;
ly=ay-dimy+1;
if (dimx>outx)||(dimy>outy)||(dimx+lx-1>outx)||(dimy+ly-1>outy)
out=[];
return;
else
out=out(dimx:dimx+lx-1,dimy:dimy+ly-1);
return;
end
end
%---------------------------------------------
if strcmp(shape2,'same')
lx=ax;
ly=ay;
px=((dimx-1)+mod((dimx-1),2))/2;
py=((dimy-1)+mod((dimy-1),2))/2;
out=out(px+1:px+ax,py+1:py+ay);
return;
end
%---------------------------------------------
end
%-------------------------
end