[Opencv learning] DFT Transformation

Author: gnuhpc
Source: http://www.cnblogs.com/gnuhpc/

# Include "CV. H "# include" highgui. H "# include" cxcore. H "Void rotate (cvarr * src_arr, cvarr * rotate) {cvmat * TMP; cvmat q1stub, q2stub; cvmat rotate, q4stub; cvmat d1stub, d2stub; cvd3stub, d4stub; cvmat * Q1, * Q2, * Q3, * Q4; cvmat * D1, * D2, * D3, * D4; cvsize size = cvgetsize (src_arr ); cvsize dst_size = cvgetsize (dst_arr); int CX, Cy; If (dst_size.width! = Size. width) | (dst_size.height! = Size. height) {cverror (cv_stsunmatchedsizes, "cvshiftdft", "Source and Destination arrays must have the same sizes", _ file __,__ line __);} if (src_arr = dst_arr) {TMP = cvcreatemat (size. height/2, size. width/2, cvgetelemtype (src_arr);} Cx = size. width/2; // The Origin of the retrieved image. Cy = size. height/2; Q1 = cvgetsubrect (src_arr, & q1stub, cvrect (, CX, CY); // retrieve the First quadrant of the image, the Q1 Pointer Points to it q2 = cvgetsubrect (src_arr, & q2stub, cvrect (CX, 0, CX, CY); // the second quadrant of the image, directed by the Q2 pointer to it Q3 = cvgetsubrect (src_arr, & q3stub, cvrect (CX, Cy, CX, CY )); // retrieve the third quadrant of the image. The Q3 Pointer Points to it Q4 = cvgetsubrect (src_arr, & q4stub, cvrect (0, Cy, CX, CY )); // retrieve the Fourth quadrant of the image. The Q4 Pointer Points to it d1 = cvgetsubrect (src_arr, & d1stub, cvrect (, CX, CY); d2 = cvgetsubrect (src_arr, & d2stub, cvrect (CX, 0, CX, CY); D3 = cvgetsubrect (src_arr, & d3stub, cvrect (CY, Cy, CX, CY )); d4 = cvgetsubrect (src_arr, & d4stub, cvrect (0, Cy, CX, CY); If (src_arr! = Dst_arr) {If (! Cv_are_types_eq (Q1, D1) {cverror (cv_stsunmatchedsizes, "cvshiftdft", "Source and Destination arrays must have the same sizes", _ file __,__ line __);} // adjust the four quadrants of the Fourier Transform Image with the image center as the origin, // that is, the first and third quadrants are exchanged, and the second and fourth quadrants are exchanged with cvcopy (Q3, D1, 0 ); cvcopy (Q4, D2, 0); cvcopy (Q1, D3, 0); cvcopy (Q2, D4, 0 );} else {// if the source matrix is the same as the target matrix, cvcopy (Q3, TMP, 0), cvcopy (Q1, Q3, 0), and cvcopy (TMP, q1, 0); cvcopy (Q4, TMP, 0); cvcopy (Q2, Q4, 0); cvcopy (TMP, Q2, 0) ;}} int main (INT argc, char ** argv) {const char * filename = (argc> = 2? Argv [1]: "lena.jpg"); iplimage * im; iplimage * realinput, * imaginaryinput, * complexinput; iplimage * image_re, * image_im; int dft_m, dft_n; cvmat * callback; cvmat TMP; double M, M; Im = cvloadimage (filename, cv_load_image_grayscale); // load the image if (! Im) {return-1;} // allocate space realinput = cvcreateimage (cvgetsize (IM), ipl_depth_64f, 1); // single channel imaginaryinput = cvcreateimage (cvgetsize (IM), ipl_depth_64f, 1); // single channel complexinput = cvcreateimage (cvgetsize (IM), ipl_depth_64f, 2); // dual channel cvscale (IM, realinput, 1.0, 0.0 ); // # define cvscale cvconvertscale => readinput = Im cvzero (imaginaryinput); // clear the content of the image cvmerge (realinput, imaginaryinput, null, null, complexinput ); // mix the two images as two channels of complexinput/* obtain the optimal DFT size */dft_m = cvgetoptimaldftsize (im-> height-1 ); dft_n = direction (im-> width-1); dft_a = cvcreatemat (dft_m, dft_n, cv_64fc2); image_re = cvcreateimage (cvsize (dft_n, dft_m), direction, 1 ); // real-part image_im = cvcreateimage (cvsize (dft_n, dft_m), ipl_depth_64f, 1); // virtual cvgetsubrect (dft_a, & TMP, cvrect (, im-> width, im-> height); cvcopy (complexinput, & TMP, null); If (dft_a-> Cols> im-> width) // If the obtained optimal DFT size is larger than the source image in width, {cvgetsubrect (dft_a, & TMP, cvrect (im-> width, 0, dft_a-> Cols-im-> width, im-> height); cvzero (& TMP);} cvdft (dft_a, dft_a, cv_dxt_forward, complexinput-> height ); cvnamedwindow ("win", 0); cvnamedwindow ("magnhistory", 0); cvshowimage ("win", Im); // splits the real and virtual cvsplit (dft_a, image_re, image_im, 2.0); // calculate the power spectrum mag = SQRT (Re ^ 2 + Im ^ 2) cvpow (image_re, image_re, 2.0); cvpow (image_im, image_im ); cvadd (image_re, image_im, image_re, null); // image_re <= image_re + image_im cvpow (image_re, image_re, 0.5); // calculate log (1 + mag) cvadds (image_re, cvscalarall (1.0), image_re, null); cvlog (image_re, image_re); cvshiftdft (image_re, image_re); cvminmaxloc (image_re, & M, & M, null, null, null); cvscale (image_re, image_re, 1.0/(m-m), 1.0 * (-M)/(m-m); cvshowimage ("magnbench ", image_re); cvwaitkey (-1); Return 0 ;}

 

Author: gnuhpc

Source: http://www.cnblogs.com/gnuhpc/