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3rdparty/opencv-4.5.4/samples/python/texture_flow.py 1.2 KB
f4334277   Hu Chunming   提交3rdparty
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  #!/usr/bin/env python
  
  '''
  Texture flow direction estimation.
  
  Sample shows how cv.cornerEigenValsAndVecs function can be used
  to estimate image texture flow direction.
  
  Usage:
      texture_flow.py [<image>]
  '''
  
  # Python 2/3 compatibility
  from __future__ import print_function
  
  import numpy as np
  import cv2 as cv
  
  def main():
      import sys
      try:
          fn = sys.argv[1]
      except:
          fn = 'starry_night.jpg'
  
      img = cv.imread(cv.samples.findFile(fn))
      if img is None:
          print('Failed to load image file:', fn)
          sys.exit(1)
  
      gray = cv.cvtColor(img, cv.COLOR_BGR2GRAY)
      h, w = img.shape[:2]
  
      eigen = cv.cornerEigenValsAndVecs(gray, 15, 3)
      eigen = eigen.reshape(h, w, 3, 2)  # [[e1, e2], v1, v2]
      flow = eigen[:,:,2]
  
      vis = img.copy()
      vis[:] = (192 + np.uint32(vis)) / 2
      d = 12
      points =  np.dstack( np.mgrid[d/2:w:d, d/2:h:d] ).reshape(-1, 2)
      for x, y in np.int32(points):
          vx, vy = np.int32(flow[y, x]*d)
          cv.line(vis, (x-vx, y-vy), (x+vx, y+vy), (0, 0, 0), 1, cv.LINE_AA)
      cv.imshow('input', img)
      cv.imshow('flow', vis)
      cv.waitKey()
  
      print('Done')
  
  
  if __name__ == '__main__':
      print(__doc__)
      main()
      cv.destroyAllWindows()