X-Git-Url: http://vcs.maemo.org/git/?a=blobdiff_plain;f=samples%2Fswig_python%2Fdft.py;fp=samples%2Fswig_python%2Fdft.py;h=13be2f7f7c336dd93b6cc780b0fee9d9d788e87a;hb=e4c14cdbdf2fe805e79cd96ded236f57e7b89060;hp=0000000000000000000000000000000000000000;hpb=454138ff8a20f6edb9b65a910101403d8b520643;p=opencv

diff --git a/samples/swig_python/dft.py b/samples/swig_python/dft.py
new file mode 100755
index 0000000..13be2f7
--- /dev/null
+++ b/samples/swig_python/dft.py
@@ -0,0 +1,107 @@
+#!/usr/bin/python
+from opencv.cv import *
+from opencv.highgui import *
+import sys
+
+# Rearrange the quadrants of Fourier image so that the origin is at
+# the image center
+# src & dst arrays of equal size & type
+def cvShiftDFT(src_arr, dst_arr ):
+
+    size = cvGetSize(src_arr)
+    dst_size = cvGetSize(dst_arr)
+
+    if(dst_size.width != size.width or 
+            dst_size.height != size.height) :
+        cvError( CV_StsUnmatchedSizes, "cvShiftDFT", "Source and Destination arrays must have equal sizes", __FILE__, __LINE__ )    
+
+    if(src_arr is dst_arr):
+        tmp = cvCreateMat(size.height/2, size.width/2, cvGetElemType(src_arr))
+    
+    cx = size.width/2
+    cy = size.height/2 # image center
+
+    q1 = cvGetSubRect( src_arr, cvRect(0,0,cx, cy) )
+    q2 = cvGetSubRect( src_arr, cvRect(cx,0,cx,cy) )
+    q3 = cvGetSubRect( src_arr, cvRect(cx,cy,cx,cy) )
+    q4 = cvGetSubRect( src_arr, cvRect(0,cy,cx,cy) )
+    d1 = cvGetSubRect( src_arr, cvRect(0,0,cx,cy) )
+    d2 = cvGetSubRect( src_arr, cvRect(cx,0,cx,cy) )
+    d3 = cvGetSubRect( src_arr, cvRect(cx,cy,cx,cy) )
+    d4 = cvGetSubRect( src_arr, cvRect(0,cy,cx,cy) )
+
+    if(src_arr is not dst_arr):
+        if( not CV_ARE_TYPES_EQ( q1, d1 )):
+            cvError( CV_StsUnmatchedFormats, "cvShiftDFT", "Source and Destination arrays must have the same format", __FILE__, __LINE__ )    
+        
+        cvCopy(q3, d1)
+        cvCopy(q4, d2)
+        cvCopy(q1, d3)
+        cvCopy(q2, d4)
+    
+    else:
+        cvCopy(q3, tmp)
+        cvCopy(q1, q3)
+        cvCopy(tmp, q1)
+        cvCopy(q4, tmp)
+        cvCopy(q2, q4)
+        cvCopy(tmp, q2)
+
+if __name__ == "__main__":
+    
+    im = cvLoadImage( sys.argv[1], CV_LOAD_IMAGE_GRAYSCALE)
+
+    realInput = cvCreateImage( cvGetSize(im), IPL_DEPTH_64F, 1)
+    imaginaryInput = cvCreateImage( cvGetSize(im), IPL_DEPTH_64F, 1)
+    complexInput = cvCreateImage( cvGetSize(im), IPL_DEPTH_64F, 2)
+
+    cvScale(im, realInput, 1.0, 0.0)
+    cvZero(imaginaryInput)
+    cvMerge(realInput, imaginaryInput, None, None, complexInput)
+
+    dft_M = cvGetOptimalDFTSize( im.height - 1 )
+    dft_N = cvGetOptimalDFTSize( im.width - 1 )
+
+    dft_A = cvCreateMat( dft_M, dft_N, CV_64FC2 )
+    image_Re = cvCreateImage( cvSize(dft_N, dft_M), IPL_DEPTH_64F, 1)
+    image_Im = cvCreateImage( cvSize(dft_N, dft_M), IPL_DEPTH_64F, 1)
+
+    # copy A to dft_A and pad dft_A with zeros
+    tmp = cvGetSubRect( dft_A, cvRect(0,0, im.width, im.height))
+    cvCopy( complexInput, tmp, None )
+    if(dft_A.width > im.width):
+        tmp = cvGetSubRect( dft_A, cvRect(im.width,0, dft_N - im.width, im.height))
+        cvZero( tmp )
+
+    # no need to pad bottom part of dft_A with zeros because of
+    # use nonzero_rows parameter in cvDFT() call below
+
+    cvDFT( dft_A, dft_A, CV_DXT_FORWARD, complexInput.height )
+
+    cvNamedWindow("win", 0)
+    cvNamedWindow("magnitude", 0)
+    cvShowImage("win", im)
+
+    # Split Fourier in real and imaginary parts
+    cvSplit( dft_A, image_Re, image_Im, None, None )
+
+    # Compute the magnitude of the spectrum Mag = sqrt(Re^2 + Im^2)
+    cvPow( image_Re, image_Re, 2.0)
+    cvPow( image_Im, image_Im, 2.0)
+    cvAdd( image_Re, image_Im, image_Re, None)
+    cvPow( image_Re, image_Re, 0.5 )
+
+    # Compute log(1 + Mag)
+    cvAddS( image_Re, cvScalarAll(1.0), image_Re, None ) # 1 + Mag
+    cvLog( image_Re, image_Re ) # log(1 + Mag)
+
+
+    # Rearrange the quadrants of Fourier image so that the origin is at
+    # the image center
+    cvShiftDFT( image_Re, image_Re )
+
+    min, max, pt1, pt2 = cvMinMaxLoc(image_Re)
+    cvScale(image_Re, image_Re, 1.0/(max-min), 1.0*(-min)/(max-min))
+    cvShowImage("magnitude", image_Re)
+
+    cvWaitKey(0)