work on motempl.py sample

samples/python2/motempl.py

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+import numpy as np
+import cv2, cv
+import video
+from common import nothing, clock, draw_str
+
+MHI_DURATION = 1.0
+DEFAULT_THRESHOLD = 16
+MAX_TIME_DELTA = 0.5
+MIN_TIME_DELTA = 0.05
+
+
+if __name__ == '__main__':
+    import sys
+    try: video_src = sys.argv[1]
+    except: video_src = 'synth:class=chess:bg=../cpp/lena.jpg:noise=0.01'
+
+    cv2.namedWindow('motempl')
+    visuals = ['input', 'frame_diff', 'motion_hist', 'grad_orient']
+    cv2.createTrackbar('visual', 'motempl', 2, len(visuals)-1, nothing)
+    cv2.createTrackbar('threshold', 'motempl', DEFAULT_THRESHOLD, 255, nothing)
+
+    cam = video.create_capture(video_src)
+    ret, frame = cam.read()
+    h, w = frame.shape[:2]
+    prev_frame = frame.copy()
+    motion_history = np.zeros((h, w), np.float32)
+    hsv = np.zeros((h, w, 3), np.uint8)
+    hsv[:,:,1] = 255
+    while True:
+        ret, frame = cam.read()
+        frame_diff = cv2.absdiff(frame, prev_frame)
+        gray_diff = cv2.cvtColor(frame_diff, cv.CV_BGR2GRAY)
+        thrs = cv2.getTrackbarPos('threshold', 'motempl')
+        ret, motion_mask = cv2.threshold(gray_diff, thrs, 255, cv2.THRESH_BINARY)
+        timestamp = clock()
+        cv2.updateMotionHistory(motion_mask, motion_history, timestamp, MHI_DURATION)
+        mg_mask, mg_orient = cv2.calcMotionGradient( motion_history, MAX_TIME_DELTA, MIN_TIME_DELTA, apertureSize=5 );
+
+        visual_name = visuals[cv2.getTrackbarPos('visual', 'motempl')]
+        if visual_name == 'input':
+            vis = frame.copy()
+        elif visual_name == 'frame_diff':
+            vis = frame_diff.copy()
+        elif visual_name == 'motion_hist':
+            vis = np.uint8(np.clip((motion_history-(timestamp-MHI_DURATION)) / MHI_DURATION, 0, 1)*255)
+            vis = cv2.cvtColor(vis, cv.CV_GRAY2BGR)
+        elif visual_name == 'grad_orient':
+            hsv[:,:,0] = mg_orient/2
+            hsv[:,:,2] = mg_mask*255
+            vis = cv2.cvtColor(hsv, cv.CV_HSV2BGR)
+        draw_str(vis, (20, 20), visual_name)
+        cv2.imshow('motempl', vis)
+
+        prev_frame = frame.copy()
+        if cv2.waitKey(5) == 27:
+            break