Fourier-Mellin based Image Registration (with GUI): crosspowerspectrum(in1,in2) - File Exchange

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Highlights from
Fourier-Mellin based Image Registration (with GUI)

fm_gui.m
crosspowerspectrum(in1,in2) USAGE : cps = crosspowerspectrum(in1,in2)
fm_guifun(action) GUI functions for Fourier-Mellin transform GUI
fm_parse_inputs(data) fm_parse_inputs(data)
fourier_mellin(data) USAGE : [combImage,registered1,registered2,reg_output,cps_rs,cps_trans] = fourier_mellin(data)
hipass_filter(ht,wd) hi-pass filter function
image_scale(input,lower,upper) USAGE : output = image_scale(input,lower,upper)
imlogpolar(varargin) IMLOGPOLAR Compute logarithmic polar transformation of image.
parse_inputs(varargin)
readpgm( filename )
transformImage(A,Ar,Ac,Nrho,N...
w=window1d(p,wtype,param) USAGE: w=window1d(p,wtype,param)
w=window2d(p,q,wtype,param)
zeropad(i1,i2,centre_flag)
fft_resize_test.m
help_fm.html
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from Fourier-Mellin based Image Registration (with GUI) by Adam Wilmer
GUI-implementation of the Fourier-Mellin transform for simple image rotation, scale and translation.

crosspowerspectrum(in1,in2)

function cps = crosspowerspectrum(in1,in2)
% USAGE : cps = crosspowerspectrum(in1,in2)
%
% function to calculate the PHASE-CORRELATION, hence function name may be a bit misleading!!
%
% Adam Wilmer, 3-9-02

F1 = fft2(in1);
F2 = fft2(in2);

% Create phase difference matrix
pdm = exp(i*(angle(F1)-angle(F2)));

% turn into cross phase-correlation
cps = real(ifft2(pdm));

% had problems with NaN's coming out so check this
if(mean(mean(isnan(cps)))>0.95)
    disp('PROBLEM ALERT: phasecorrelation contains a lot of NaNs (check FFTs exist as they cannot cope with certain inputs for some reason)')
    return
end

Highlights from Fourier-Mellin based Image Registration (with GUI)

Highlights from
Fourier-Mellin based Image Registration (with GUI)