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view_phase_diff.py

This scripts displays the phase difference (in degrees) between corresponding pixels in the Fourier Transforms of the two input images, which must be of the same size. The Fourier Transforms honor the origin of the reference system, which is assumed to be at the center of the two images

Usage:

dng view_phase_diff.py <image1> <image2>



1 import sys
2 import math
3 import ost.img.alg
4 
5 if len(sys.argv)==2:
6  image1=io.LoadImage(sys.argv[1])
7  image2=io.LoadImage(sys.argv[2])
8 else:
9  image1=io.LoadImage('square.png')
10  image2=io.LoadImage('circle.png')
11 if image1.GetExtent() != image2.GetExtent():
12  raise RuntimeError('The input images should have the same size.')
13 image1.CenterSpatialOrigin()
14 image2.CenterSpatialOrigin()
15 image1.ApplyIP(ost.img.alg.DFT())
16 image2.ApplyIP(ost.img.alg.DFT())
17 ex_it=img.ExtentIterator(image1.GetExtent())
18 diff_image=img.CreateImage(image1.GetExtent())
19 for pixel in ex_it:
20  phase1=img.Phase(image1.GetComplex(pixel))
21  phase2=img.Phase(image2.GetComplex(pixel))
22  phase_diff=phase1-phase2
23  diff_image.SetReal(pixel,180.0*float(phase_diff)/math.pi)
24 v=gui.CreateDataViewer(diff_image,"Phase difference (in degrees)")