Added ocv_opticalflow_dense.py

ocv_opticalflow_dense.py

@@ -0,0 +1,29 @@
+import numpy as np
+import cv2 as cv
+cap = cv.VideoCapture(cv.samples.findFile('data/production_id 4525346 (1080p).mp4'))
+ret, frame1 = cap.read()
+prvs = cv.cvtColor(frame1, cv.COLOR_BGR2GRAY)
+hsv = np.zeros_like(frame1)
+hsv[..., 1] = 255
+while(1):
+    ret, frame2 = cap.read()
+    if not ret:
+        print('No frames grabbed!')
+        break
+
+    next = cv.cvtColor(frame2, cv.COLOR_BGR2GRAY)
+    flow = cv.calcOpticalFlowFarneback(prvs, next, None, 0.5, 3, 15, 3, 5, 1.2, 0)
+    mag, ang = cv.cartToPolar(flow[..., 0], flow[..., 1])
+    hsv[..., 0] = ang*180/np.pi/2
+    hsv[..., 2] = cv.normalize(mag, None, 0, 255, cv.NORM_MINMAX)
+    bgr = cv.cvtColor(hsv, cv.COLOR_HSV2BGR)
+    cv.imshow('frame2', bgr)
+    k = cv.waitKey(30) & 0xff
+    if k == 27:
+        break
+    elif k == ord('s'):
+        cv.imwrite('opticalfb.png', frame2)
+        cv.imwrite('opticalhsv.png', bgr)
+    prvs = next
+
+cv.destroyAllWindows()