optflow_utils.py 文件源码

def sparse_optical_flow(im1, im2, pts, fb_threshold=-1, 
                        window_size=15, max_level=2, 
                        criteria=(cv2.TERM_CRITERIA_EPS | cv2.TERM_CRITERIA_COUNT, 10, 0.03)): 

    # Forward flow
    p1, st, err = cv2.calcOpticalFlowPyrLK(im1, im2, pts, None, 
                                           winSize=(window_size, window_size), 
                                           maxLevel=max_level, criteria=criteria )

    # Backward flow
    if fb_threshold > 0:     
        p0r, st0, err = cv2.calcOpticalFlowPyrLK(im2, im1, p1, None, 
                                           winSize=(window_size, window_size), 
                                           maxLevel=max_level, criteria=criteria)
        p0r[st0 == 0] = np.nan

        # Set only good
        fb_good = (np.fabs(p0r-p0) < fb_threshold).all(axis=1)

        p1[~fb_good] = np.nan
        st = np.bitwise_and(st, st0)
        err[~fb_good] = np.nan

    return p1, st, err