mirror of
https://github.com/opencv/opencv.git
synced 2024-11-30 06:10:02 +08:00
115 lines
3.9 KiB
Python
Executable File
115 lines
3.9 KiB
Python
Executable File
#!/usr/bin/python
|
|
import cv2.cv as 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://raw.github.com/Itseez/opencv/master/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)
|
|
cv.DestroyAllWindows()
|