5.2-dense-optical-flow.py

import cv2 
import numpy as np

cap = cv2.VideoCapture(0)
ret, frame1 = cap.read()

prvsImg = cv2.cvtColor(frame1, cv2.COLOR_BGR2GRAY)

hsv_mask = np.zeros_like(frame1)
hsv_mask[:, :, 1] = 255

while True:
    ret, frame2 = cap.read()
    nextImg = cv2.cvtColor(frame2, cv2.COLOR_BGR2GRAY)
    
    flow = cv2.calcOpticalFlowFarneback(prvsImg, nextImg, None, 0.5, 3, 15, 3, 5, 1.2, 0)

    mag, ang = cv2.cartToPolar(flow[:, :, 0],  flow[:, :, 1], angleInDegrees=True)
    hsv_mask[:, :, 0] = ang / 2
    hsv_mask[:, :, 2] = cv2.normalize(mag, None, 0, 255, cv2.NORM_MINMAX)
    
    bgr = cv2.cvtColor(hsv_mask, cv2.COLOR_HSV2BGR)
    cv2.imshow("frame", bgr)
    
    if cv2.waitKey(30) == ord("q"):
        break

    prvsImg = nextImg

    
cap.release()
cv2.destroyAllWindows()