digital_display_ocr.py 文件源码

def normalize_contrs(img,cntr_pts):
  ratio = img.shape[0] / 300.0
  norm_pts = np.zeros((4,2), dtype="float32")

  s = cntr_pts.sum(axis=1)
  norm_pts[0] = cntr_pts[np.argmin(s)]
  norm_pts[2] = cntr_pts[np.argmax(s)]

  d = np.diff(cntr_pts,axis=1)
  norm_pts[1] = cntr_pts[np.argmin(d)]
  norm_pts[3] = cntr_pts[np.argmax(d)]

  norm_pts *= ratio

  (top_left, top_right, bottom_right, bottom_left) = norm_pts

  width1 = np.sqrt(((bottom_right[0] - bottom_left[0]) ** 2) + ((bottom_right[1] - bottom_left[1]) ** 2))
  width2 = np.sqrt(((top_right[0] - top_left[0]) ** 2) + ((top_right[1] - top_left[1]) ** 2))
  height1 = np.sqrt(((top_right[0] - bottom_right[0]) ** 2) + ((top_right[1] - bottom_right[1]) ** 2))
  height2 = np.sqrt(((top_left[0] - bottom_left[0]) ** 2) + ((top_left[1] - bottom_left[1]) ** 2))

  max_width = max(int(width1), int(width2))
  max_height = max(int(height1), int(height2))

  dst = np.array([[0,0], [max_width -1, 0],[max_width -1, max_height -1],[0, max_height-1]], dtype="float32")
  persp_matrix = cv2.getPerspectiveTransform(norm_pts,dst)
  return cv2.warpPerspective(img,persp_matrix,(max_width,max_height))