1 #!/usr/bin/env python 2 3 ''' 4 Distance transform sample. 5 6 Usage: 7 distrans.py [<image>] 8 9 Keys: 10 ESC - exit 11 v - toggle voronoi mode 12 ''' 13 14 15 import numpy as np 16 import cv2 17 18 from common import make_cmap 19 20 if __name__ == '__main__': 21 import sys 22 try: 23 fn = sys.argv[1] 24 except: 25 fn = '../data/fruits.jpg' 26 print __doc__ 27 28 img = cv2.imread(fn, 0) 29 if img is None: 30 print 'Failed to load fn:', fn 31 sys.exit(1) 32 33 cm = make_cmap('jet') 34 need_update = True 35 voronoi = False 36 37 def update(dummy=None): 38 global need_update 39 need_update = False 40 thrs = cv2.getTrackbarPos('threshold', 'distrans') 41 mark = cv2.Canny(img, thrs, 3*thrs) 42 dist, labels = cv2.distanceTransformWithLabels(~mark, cv2.DIST_L2, 5) 43 if voronoi: 44 vis = cm[np.uint8(labels)] 45 else: 46 vis = cm[np.uint8(dist*2)] 47 vis[mark != 0] = 255 48 cv2.imshow('distrans', vis) 49 50 def invalidate(dummy=None): 51 global need_update 52 need_update = True 53 54 cv2.namedWindow('distrans') 55 cv2.createTrackbar('threshold', 'distrans', 60, 255, invalidate) 56 update() 57 58 59 while True: 60 ch = 0xFF & cv2.waitKey(50) 61 if ch == 27: 62 break 63 if ch == ord('v'): 64 voronoi = not voronoi 65 print 'showing', ['distance', 'voronoi'][voronoi] 66 update() 67 if need_update: 68 update() 69 cv2.destroyAllWindows() 70
