"atomic bomb" commit. Reorganized OpenCV directory structure

samples/python/dft.py

@@ -0,0 +1,113 @@
+#!/usr/bin/python
+import cv
+import sys
+import urllib2
+
+# 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 = cv.GetSize(src_arr)
+    dst_size = cv.GetSize(dst_arr)
+
+    if dst_size != size:
+        cv.Error( cv.CV_StsUnmatchedSizes, "cv.ShiftDFT", "Source and Destination arrays must have equal sizes", __FILE__, __LINE__ )    
+
+    if(src_arr is dst_arr):
+        tmp = cv.CreateMat(size[1]/2, size[0]/2, cv.GetElemType(src_arr))
+    
+    cx = size[0] / 2
+    cy = size[1] / 2 # image center
+
+    q1 = cv.GetSubRect( src_arr, (0,0,cx, cy) )
+    q2 = cv.GetSubRect( src_arr, (cx,0,cx,cy) )
+    q3 = cv.GetSubRect( src_arr, (cx,cy,cx,cy) )
+    q4 = cv.GetSubRect( src_arr, (0,cy,cx,cy) )
+    d1 = cv.GetSubRect( src_arr, (0,0,cx,cy) )
+    d2 = cv.GetSubRect( src_arr, (cx,0,cx,cy) )
+    d3 = cv.GetSubRect( src_arr, (cx,cy,cx,cy) )
+    d4 = cv.GetSubRect( src_arr, (0,cy,cx,cy) )
+
+    if(src_arr is not dst_arr):
+        if( not cv.CV_ARE_TYPES_EQ( q1, d1 )):
+            cv.Error( cv.CV_StsUnmatchedFormats, "cv.ShiftDFT", "Source and Destination arrays must have the same format", __FILE__, __LINE__ )    
+        
+        cv.Copy(q3, d1)
+        cv.Copy(q4, d2)
+        cv.Copy(q1, d3)
+        cv.Copy(q2, d4)
+    
+    else:
+        cv.Copy(q3, tmp)
+        cv.Copy(q1, q3)
+        cv.Copy(tmp, q1)
+        cv.Copy(q4, tmp)
+        cv.Copy(q2, q4)
+        cv.Copy(tmp, q2)
+
+if __name__ == "__main__":
+    
+    if len(sys.argv) > 1:
+        im = cv.LoadImage( sys.argv[1], cv.CV_LOAD_IMAGE_GRAYSCALE)
+    else:
+        url = 'https://code.ros.org/svn/opencv/trunk/opencv/samples/c/baboon.jpg'
+        filedata = urllib2.urlopen(url).read()
+        imagefiledata = cv.CreateMatHeader(1, len(filedata), cv.CV_8UC1)
+        cv.SetData(imagefiledata, filedata, len(filedata))
+        im = cv.DecodeImageM(imagefiledata, cv.CV_LOAD_IMAGE_GRAYSCALE)
+
+    realInput = cv.CreateImage( cv.GetSize(im), cv.IPL_DEPTH_64F, 1)
+    imaginaryInput = cv.CreateImage( cv.GetSize(im), cv.IPL_DEPTH_64F, 1)
+    complexInput = cv.CreateImage( cv.GetSize(im), cv.IPL_DEPTH_64F, 2)
+
+    cv.Scale(im, realInput, 1.0, 0.0)
+    cv.Zero(imaginaryInput)
+    cv.Merge(realInput, imaginaryInput, None, None, complexInput)
+
+    dft_M = cv.GetOptimalDFTSize( im.height - 1 )
+    dft_N = cv.GetOptimalDFTSize( im.width - 1 )
+
+    dft_A = cv.CreateMat( dft_M, dft_N, cv.CV_64FC2 )
+    image_Re = cv.CreateImage( (dft_N, dft_M), cv.IPL_DEPTH_64F, 1)
+    image_Im = cv.CreateImage( (dft_N, dft_M), cv.IPL_DEPTH_64F, 1)
+
+    # copy A to dft_A and pad dft_A with zeros
+    tmp = cv.GetSubRect( dft_A, (0,0, im.width, im.height))
+    cv.Copy( complexInput, tmp, None )
+    if(dft_A.width > im.width):
+        tmp = cv.GetSubRect( dft_A, (im.width,0, dft_N - im.width, im.height))
+        cv.Zero( tmp )
+
+    # no need to pad bottom part of dft_A with zeros because of
+    # use nonzero_rows parameter in cv.FT() call below
+
+    cv.DFT( dft_A, dft_A, cv.CV_DXT_FORWARD, complexInput.height )
+
+    cv.NamedWindow("win", 0)
+    cv.NamedWindow("magnitude", 0)
+    cv.ShowImage("win", im)
+
+    # Split Fourier in real and imaginary parts
+    cv.Split( dft_A, image_Re, image_Im, None, None )
+
+    # Compute the magnitude of the spectrum Mag = sqrt(Re^2 + Im^2)
+    cv.Pow( image_Re, image_Re, 2.0)
+    cv.Pow( image_Im, image_Im, 2.0)
+    cv.Add( image_Re, image_Im, image_Re, None)
+    cv.Pow( image_Re, image_Re, 0.5 )
+
+    # Compute log(1 + Mag)
+    cv.AddS( image_Re, cv.ScalarAll(1.0), image_Re, None ) # 1 + Mag
+    cv.Log( 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 = cv.MinMaxLoc(image_Re)
+    cv.Scale(image_Re, image_Re, 1.0/(max-min), 1.0*(-min)/(max-min))
+    cv.ShowImage("magnitude", image_Re)
+
+    cv.WaitKey(0)