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#!/usr/bin/env python
'''
This sample demonstrates Canny edge detection.
Usage:
edge.py [<video source>]
Trackbars control edge thresholds.
'''
import cv2
import video
import sys
if __name__ == '__main__':
print __doc__
try: fn = sys.argv[1]
except: fn = 0
def nothing(*arg):
pass
cv2.namedWindow('edge')
cv2.createTrackbar('thrs1', 'edge', 2000, 5000, nothing)
cv2.createTrackbar('thrs2', 'edge', 4000, 5000, nothing)
cap = video.create_capture(fn)
while True:
flag, img = cap.read()
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
thrs1 = cv2.getTrackbarPos('thrs1', 'edge')
thrs2 = cv2.getTrackbarPos('thrs2', 'edge')
edge = cv2.Canny(gray, thrs1, thrs2, apertureSize=5)
vis = img.copy()
vis /= 2
vis[edge != 0] = (0, 255, 0)
cv2.imshow('edge', vis)
ch = cv2.waitKey(5)
if ch == 27:
break
cv2.destroyAllWindows()