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3rdparty/opencv-4.5.4/modules/python/test/test_dft.py 1.44 KB
f4334277   Hu Chunming   提交3rdparty
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  #!/usr/bin/env python
  
  '''
  Test for disctrete fourier transform (dft)
  '''
  
  # Python 2/3 compatibility
  from __future__ import print_function
  
  import cv2 as cv
  import numpy as np
  import sys
  
  from tests_common import NewOpenCVTests
  
  class dft_test(NewOpenCVTests):
      def test_dft(self):
  
          img = self.get_sample('samples/data/rubberwhale1.png', 0)
          eps = 0.001
  
          #test direct transform
          refDft = np.fft.fft2(img)
          refDftShift = np.fft.fftshift(refDft)
          refMagnitide = np.log(1.0 + np.abs(refDftShift))
  
          testDft = cv.dft(np.float32(img),flags = cv.DFT_COMPLEX_OUTPUT)
          testDftShift = np.fft.fftshift(testDft)
          testMagnitude = np.log(1.0 + cv.magnitude(testDftShift[:,:,0], testDftShift[:,:,1]))
  
          refMagnitide = cv.normalize(refMagnitide, 0.0, 1.0, cv.NORM_MINMAX)
          testMagnitude = cv.normalize(testMagnitude, 0.0, 1.0, cv.NORM_MINMAX)
  
          self.assertLess(cv.norm(refMagnitide - testMagnitude), eps)
  
          #test inverse transform
          img_back = np.fft.ifft2(refDft)
          img_back = np.abs(img_back)
  
          img_backTest = cv.idft(testDft)
          img_backTest = cv.magnitude(img_backTest[:,:,0], img_backTest[:,:,1])
  
          img_backTest = cv.normalize(img_backTest, 0.0, 1.0, cv.NORM_MINMAX)
          img_back = cv.normalize(img_back, 0.0, 1.0, cv.NORM_MINMAX)
  
          self.assertLess(cv.norm(img_back - img_backTest), eps)
  
  
  if __name__ == '__main__':
      NewOpenCVTests.bootstrap()