initial commit

samples/python/distrans.py

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+#!/usr/bin/env python
+
+'''
+Distance transform sample.
+
+Usage:
+  distrans.py [<image>]
+
+Keys:
+  ESC   - exit
+  v     - toggle voronoi mode
+'''
+
+# Python 2/3 compatibility
+from __future__ import print_function
+
+import numpy as np
+import cv2 as cv
+
+from common import make_cmap
+
+def main():
+    import sys
+    try:
+        fn = sys.argv[1]
+    except:
+        fn = 'fruits.jpg'
+
+    fn = cv.samples.findFile(fn)
+    img = cv.imread(fn, cv.IMREAD_GRAYSCALE)
+    if img is None:
+        print('Failed to load fn:', fn)
+        sys.exit(1)
+
+    cm = make_cmap('jet')
+    need_update = True
+    voronoi = False
+
+    def update(dummy=None):
+        global need_update
+        need_update = False
+        thrs = cv.getTrackbarPos('threshold', 'distrans')
+        mark = cv.Canny(img, thrs, 3*thrs)
+        dist, labels = cv.distanceTransformWithLabels(~mark, cv.DIST_L2, 5)
+        if voronoi:
+            vis = cm[np.uint8(labels)]
+        else:
+            vis = cm[np.uint8(dist*2)]
+        vis[mark != 0] = 255
+        cv.imshow('distrans', vis)
+
+    def invalidate(dummy=None):
+        global need_update
+        need_update = True
+
+    cv.namedWindow('distrans')
+    cv.createTrackbar('threshold', 'distrans', 60, 255, invalidate)
+    update()
+
+
+    while True:
+        ch = cv.waitKey(50)
+        if ch == 27:
+            break
+        if ch == ord('v'):
+            voronoi = not voronoi
+            print('showing', ['distance', 'voronoi'][voronoi])
+            update()
+        if need_update:
+            update()
+
+    print('Done')
+
+
+if __name__ == '__main__':
+    print(__doc__)
+    main()
+    cv.destroyAllWindows()