116 lines
3.4 KiB
Mathematica
116 lines
3.4 KiB
Mathematica
#! /usr/bin/env octave
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cv;
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highgui;
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## Rearrange the quadrants of Fourier image so that the origin is at
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## the image center
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## src & dst arrays of equal size & type
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function cvShiftDFT(src_arr, dst_arr )
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size = cvGetSize(src_arr);
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dst_size = cvGetSize(dst_arr);
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if(dst_size.width != size.width || \
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dst_size.height != size.height)
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cvError( CV_StsUnmatchedSizes, "cvShiftDFT", \
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"Source and Destination arrays must have equal sizes", \
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__FILE__, __LINE__ );
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endif
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if(swig_this(src_arr) == swig_this(dst_arr))
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tmp = cvCreateMat(size.height/2, size.width/2, cvGetElemType(src_arr));
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endif
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cx = size.width/2;
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cy = size.height/2; # image center
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q1 = cvGetSubRect( src_arr, cvRect(0,0,cx, cy) );
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q2 = cvGetSubRect( src_arr, cvRect(cx,0,cx,cy) );
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q3 = cvGetSubRect( src_arr, cvRect(cx,cy,cx,cy) );
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q4 = cvGetSubRect( src_arr, cvRect(0,cy,cx,cy) );
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d1 = cvGetSubRect( src_arr, cvRect(0,0,cx,cy) );
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d2 = cvGetSubRect( src_arr, cvRect(cx,0,cx,cy) );
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d3 = cvGetSubRect( src_arr, cvRect(cx,cy,cx,cy) );
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d4 = cvGetSubRect( src_arr, cvRect(0,cy,cx,cy) );
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if(swig_this(src_arr) != swig_this(dst_arr))
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if( !CV_ARE_TYPES_EQ( q1, d1 ))
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cvError( CV_StsUnmatchedFormats, \
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"cvShiftDFT", "Source and Destination arrays must have the same format", \
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__FILE__, __LINE__ );
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endif
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cvCopy(q3, d1);
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cvCopy(q4, d2);
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cvCopy(q1, d3);
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cvCopy(q2, d4);
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else
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cvCopy(q3, tmp);
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cvCopy(q1, q3);
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cvCopy(tmp, q1);
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cvCopy(q4, tmp);
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cvCopy(q2, q4);
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cvCopy(tmp, q2);
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endif
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endfunction
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im = cvLoadImage( argv(){1}, CV_LOAD_IMAGE_GRAYSCALE);
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realInput = cvCreateImage( cvGetSize(im), IPL_DEPTH_64F, 1);
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imaginaryInput = cvCreateImage( cvGetSize(im), IPL_DEPTH_64F, 1);
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complexInput = cvCreateImage( cvGetSize(im), IPL_DEPTH_64F, 2);
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cvScale(im, realInput, 1.0, 0.0);
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cvZero(imaginaryInput);
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cvMerge(realInput, imaginaryInput, [], [], complexInput);
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dft_M = cvGetOptimalDFTSize( im.height - 1 );
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dft_N = cvGetOptimalDFTSize( im.width - 1 );
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dft_A = cvCreateMat( dft_M, dft_N, CV_64FC2 );
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image_Re = cvCreateImage( cvSize(dft_N, dft_M), IPL_DEPTH_64F, 1);
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image_Im = cvCreateImage( cvSize(dft_N, dft_M), IPL_DEPTH_64F, 1);
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## copy A to dft_A and pad dft_A with zeros
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tmp = cvGetSubRect( dft_A, cvRect(0,0, im.width, im.height));
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cvCopy( complexInput, tmp, [] );
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if(dft_A.width > im.width)
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tmp = cvGetSubRect( dft_A, cvRect(im.width,0, dft_N - im.width, im.height));
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cvZero( tmp );
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endif
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## no need to pad bottom part of dft_A with zeros because of
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## use nonzero_rows parameter in cvDFT() call below
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cvDFT( dft_A, dft_A, CV_DXT_FORWARD, complexInput.height );
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cvNamedWindow("win", 0);
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cvNamedWindow("magnitude", 0);
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cvShowImage("win", im);
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## Split Fourier in real and imaginary parts
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cvSplit( dft_A, image_Re, image_Im, [], [] );
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## Compute the magnitude of the spectrum Mag = sqrt(Re^2 + Im^2)
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cvPow( image_Re, image_Re, 2.0);
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cvPow( image_Im, image_Im, 2.0);
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cvAdd( image_Re, image_Im, image_Re, []);
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cvPow( image_Re, image_Re, 0.5 );
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## Compute log(1 + Mag)
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cvAddS( image_Re, cvScalarAll(1.0), image_Re, [] ); # 1 + Mag
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cvLog( image_Re, image_Re ); # log(1 + Mag)
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## Rearrange the quadrants of Fourier image so that the origin is at
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## the image center
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cvShiftDFT( image_Re, image_Re );
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[min, max] = cvMinMaxLoc(image_Re);
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cvScale(image_Re, image_Re, 1.0/(max-min), 1.0*(-min)/(max-min));
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cvShowImage("magnitude", image_Re);
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cvWaitKey(-1);
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