140 lines
4.3 KiB
C
140 lines
4.3 KiB
C
#define CV_NO_BACKWARD_COMPATIBILITY
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#include <cxcore.h>
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#include <cv.h>
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#include <highgui.h>
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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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void cvShiftDFT(CvArr * src_arr, CvArr * dst_arr )
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{
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CvMat * tmp=0;
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CvMat q1stub, q2stub;
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CvMat q3stub, q4stub;
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CvMat d1stub, d2stub;
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CvMat d3stub, d4stub;
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CvMat * q1, * q2, * q3, * q4;
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CvMat * d1, * d2, * d3, * d4;
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CvSize size = cvGetSize(src_arr);
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CvSize dst_size = cvGetSize(dst_arr);
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int cx, cy;
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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", "Source and Destination arrays must have equal sizes", __FILE__, __LINE__ );
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}
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if(src_arr==dst_arr){
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tmp = cvCreateMat(size.height/2, size.width/2, cvGetElemType(src_arr));
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}
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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, &q1stub, cvRect(0,0,cx, cy) );
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q2 = cvGetSubRect( src_arr, &q2stub, cvRect(cx,0,cx,cy) );
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q3 = cvGetSubRect( src_arr, &q3stub, cvRect(cx,cy,cx,cy) );
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q4 = cvGetSubRect( src_arr, &q4stub, cvRect(0,cy,cx,cy) );
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d1 = cvGetSubRect( src_arr, &d1stub, cvRect(0,0,cx,cy) );
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d2 = cvGetSubRect( src_arr, &d2stub, cvRect(cx,0,cx,cy) );
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d3 = cvGetSubRect( src_arr, &d3stub, cvRect(cx,cy,cx,cy) );
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d4 = cvGetSubRect( src_arr, &d4stub, cvRect(0,cy,cx,cy) );
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if(src_arr!=dst_arr){
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if( !CV_ARE_TYPES_EQ( q1, d1 )){
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cvError( CV_StsUnmatchedFormats, "cvShiftDFT", "Source and Destination arrays must have the same format", __FILE__, __LINE__ );
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}
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cvCopy(q3, d1, 0);
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cvCopy(q4, d2, 0);
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cvCopy(q1, d3, 0);
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cvCopy(q2, d4, 0);
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}
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else{
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cvCopy(q3, tmp, 0);
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cvCopy(q1, q3, 0);
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cvCopy(tmp, q1, 0);
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cvCopy(q4, tmp, 0);
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cvCopy(q2, q4, 0);
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cvCopy(tmp, q2, 0);
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}
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}
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int main(int argc, char ** argv)
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{
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const char* filename = argc >=2 ? argv[1] : "lena.jpg";
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IplImage * im;
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IplImage * realInput;
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IplImage * imaginaryInput;
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IplImage * complexInput;
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int dft_M, dft_N;
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CvMat* dft_A, tmp;
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IplImage * image_Re;
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IplImage * image_Im;
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double m, M;
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im = cvLoadImage( filename, CV_LOAD_IMAGE_GRAYSCALE );
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if( !im )
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return -1;
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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, NULL, NULL, 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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cvGetSubRect( dft_A, &tmp, cvRect(0,0, im->width, im->height));
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cvCopy( complexInput, &tmp, NULL );
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if( dft_A->cols > im->width )
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{
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cvGetSubRect( dft_A, &tmp, cvRect(im->width,0, dft_A->cols - im->width, im->height));
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cvZero( &tmp );
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}
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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, 0, 0 );
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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, NULL);
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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, NULL ); // 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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cvMinMaxLoc(image_Re, &m, &M, NULL, NULL, NULL);
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cvScale(image_Re, image_Re, 1.0/(M-m), 1.0*(-m)/(M-m));
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cvShowImage("magnitude", image_Re);
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cvWaitKey(-1);
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return 0;
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}
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