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> 

import sys
import math
import ost.img.alg
 
if len(sys.argv)==2:
  image1=io.LoadImage(sys.argv[1])
  image2=io.LoadImage(sys.argv[2])
else:
  image1=io.LoadImage('square.png')
  image2=io.LoadImage('circle.png')
if image1.GetExtent() != image2.GetExtent():
  raise RuntimeError('The input images should have the same size.')
image1.CenterSpatialOrigin()
image2.CenterSpatialOrigin()
image1.ApplyIP(ost.img.alg.DFT())
image2.ApplyIP(ost.img.alg.DFT())
ex_it=img.ExtentIterator(image1.GetExtent())
diff_image=img.CreateImage(image1.GetExtent())
for pixel in ex_it:
  phase1=img.Phase(image1.GetComplex(pixel))
  phase2=img.Phase(image2.GetComplex(pixel))
  phase_diff=phase1-phase2
  diff_image.SetReal(pixel,180.0*float(phase_diff)/math.pi)
v=gui.CreateDataViewer(diff_image,"Phase difference (in degrees)")