Python cv2.OPTFLOW_FARNEBACK_GAUSSIAN Examples
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code examples of cv2.OPTFLOW_FARNEBACK_GAUSSIAN().
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Example #1
Source File: tracking_engine.py From DetectAndTrack with Apache License 2.0 | 6 votes |
def run_farneback(frames): try: return cv2.calcOpticalFlowFarneback( frames[0], frames[1], # options, defaults None, # output 0.5, # pyr_scale, 0.5 10, # levels, 3 min(frames[0].shape[:2]) // 5, # winsize, 15 10, # iterations, 3 7, # poly_n, 5 1.5, # poly_sigma, 1.2 cv2.OPTFLOW_FARNEBACK_GAUSSIAN, # flags, 0 ) except cv2.error: return None
Example #2
Source File: video_avi_flow.py From self-supervision with BSD 3-Clause "New" or "Revised" License | 4 votes |
def extract_optical_flow(fn, times, frames=8, scale_factor=1.0): cap = cv2.VideoCapture(fn) if not cap.isOpened(): return [] n_frames = cap.get(cv2.CAP_PROP_FRAME_COUNT) outputs = [] if n_frames < frames * 2: return outputs def resize(im): if scale_factor != 1.0: new_size = (int(im.shape[1] * scale_factor), int(im.shape[0] * scale_factor)) return cv2.resize(im, new_size, interpolation=cv2.INTER_LINEAR) else: return im for t in times: cap.set(cv2.CAP_PROP_POS_FRAMES, min(t * n_frames, n_frames - 1 - frames)) ret, frame0 = cap.read() im0 = resize(cv2.cvtColor(frame0, cv2.COLOR_BGR2GRAY)) mags = [] middle_frame = frame0 flows = [] for f in range(frames - 1): ret, frame1 = cap.read() if f == frames // 2: middle_frame = frame1 im1 = resize(cv2.cvtColor(frame1, cv2.COLOR_BGR2GRAY)) flow = cv2.calcOpticalFlowFarneback(im0, im1, None, 0.5, # py_scale 8, # levels int(40 * scale_factor), # winsize 10, # iterations 5, # poly_n 1.1, # poly_sigma cv2.OPTFLOW_FARNEBACK_GAUSSIAN) #mag, ang = cv2.cartToPolar(flow[...,0], flow[...,1]) #mags.append(mag) flows.append(flow) im0 = im1 flow = (np.mean(flows, 0) / 100).clip(-1, 1) #flow = np.mean(flows, 0) #flow /= (flow.mean() * 5 + 1e-5) #flow = flow.clip(-1, 1) #flows = flows / (np.mean(flows, 0, keepdims=True) + 1e-5) x = middle_frame[..., ::-1].astype(np.float32) / 255 outputs.append((x, flow)) return outputs