64 lines
1.9 KiB
Python
64 lines
1.9 KiB
Python
import numpy as np
|
|
import cv2 as cv
|
|
import argparse
|
|
|
|
parser = argparse.ArgumentParser(description='This sample demonstrates Lucas-Kanade Optical Flow calculation. \
|
|
The example file can be downloaded from: \
|
|
https://www.bogotobogo.com/python/OpenCV_Python/images/mean_shift_tracking/slow_traffic_small.mp4')
|
|
parser.add_argument('--image', type=str, help='path to image file', default='data/production_id 4525346 (1080p).mp4')
|
|
args = parser.parse_args()
|
|
|
|
cap = cv.VideoCapture(args.image)
|
|
|
|
# params for ShiTomasi corner detection
|
|
feature_params = dict(maxCorners=100, qualityLevel=0.3, minDistance=7, blockSize=7)
|
|
|
|
# Parameters for lucas kanade optical flow
|
|
lk_params = dict(winSize=(15, 15), maxLevel=2, criteria=(cv.TERM_CRITERIA_EPS | cv.TERM_CRITERIA_COUNT, 10, 0.03))
|
|
|
|
# Create some random colors
|
|
color = np.random.randint(0, 255, (100, 3))
|
|
|
|
# Take first frame and find corners in it
|
|
ret, old_frame = cap.read()
|
|
old_gray = cv.cvtColor(old_frame, cv.COLOR_BGR2GRAY)
|
|
p0 = cv.goodFeaturesToTrack(old_gray, mask=None, **feature_params)
|
|
|
|
# Create a mask image for drawing purposes
|
|
mask = np.zeros_like(old_frame)
|
|
|
|
while 1:
|
|
ret, frame = cap.read()
|
|
if not ret:
|
|
print('No frames grabbed!')
|
|
break
|
|
|
|
frame_gray = cv.cvtColor(frame, cv.COLOR_BGR2GRAY)
|
|
|
|
# calculate optical flow
|
|
p1, st, err = cv.calcOpticalFlowPyrLK(old_gray, frame_gray, p0, None, **lk_params)
|
|
|
|
# Select good points
|
|
if p1 is not None:
|
|
good_new = p1[st == 1]
|
|
good_old = p0[st == 1]
|
|
|
|
# draw the tracks
|
|
for i, (new, old) in enumerate(zip(good_new, good_old)):
|
|
a, b = new.ravel()
|
|
c, d = old.ravel()
|
|
mask = cv.line(mask, (int(a), int(b)), (int(c), int(d)), color[i].tolist(), 2)
|
|
frame = cv.circle(frame, (int(a), int(b)), 5, color[i].tolist(), -1)
|
|
img = cv.add(frame, mask)
|
|
|
|
cv.imshow('frame', img)
|
|
k = cv.waitKey(30) & 0xff
|
|
if k == 27:
|
|
break
|
|
|
|
# Now update the previous frame and previous points
|
|
old_gray = frame_gray.copy()
|
|
p0 = good_new.reshape(-1, 1, 2)
|
|
|
|
cv.destroyAllWindows()
|