Created
August 8, 2012 14:56
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Lucas Kanade Tracker (OpenCV)
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import cv2 | |
import numpy as np | |
import itertools | |
lk_params = dict( winSize = (10, 10), | |
maxLevel = 5, | |
criteria = (cv2.TERM_CRITERIA_EPS | cv2.TERM_CRITERIA_COUNT, 10, 0.03)) | |
feature_params = dict( maxCorners = 3000, | |
qualityLevel = 0.5, | |
minDistance = 3, | |
blockSize = 3) | |
def lk(): | |
cam = cv2.VideoCapture(0) | |
_, img = cam.read() | |
oldg = cv2.cvtColor(img, cv2.cv.CV_BGR2GRAY) | |
bb = [200,200,300,300] | |
old_pts=[] | |
while True: | |
try: | |
_, img = cam.read() | |
img1 = img[bb[0]:bb[2],bb[1]:bb[3]] | |
#print img1.shape | |
g = cv2.cvtColor(img1, cv2.cv.CV_BGR2GRAY) | |
#print g.shape | |
pt = cv2.goodFeaturesToTrack(g, **feature_params) | |
for i in xrange(len(pt)): | |
pt[i][0][0] = pt[i][0][0]+bb[0] | |
pt[i][0][1] = pt[i][0][1]+bb[1] | |
newg = cv2.cvtColor(img, cv2.cv.CV_BGR2GRAY) | |
p0 = np.float32(pt).reshape(-1, 1, 2) | |
p1, st, err = cv2.calcOpticalFlowPyrLK(oldg, newg, p0, None, **lk_params) | |
p0r, st, err = cv2.calcOpticalFlowPyrLK(newg, oldg, p1, None, **lk_params) | |
d = abs(p0-p0r).reshape(-1, 2).max(-1) | |
good = d < 1 | |
new_pts = [] | |
for pts, val in itertools.izip(p1, good): | |
if val: | |
new_pts.append([pts[0][0], pts[0][1]]) | |
cv2.circle(img, (pts[0][0], pts[0][1]), 5, thickness=3, color=(255,255,0)) | |
bb = predictBB(bb, old_pts, new_pts) | |
if bb[0]+bb[2] >= img.shape[0]: | |
bb[0] = img.shape[0] - bb[2] - 1 | |
if bb[1]+bb[3] >= img.shape[1]: | |
bb[1] = img.shape[1] - bb[3] - 1 | |
old_pts = new_pts | |
oldg = newg | |
cv2.rectangle(img, (bb[0],bb[1]),(bb[0]+bb[2],bb[1]+bb[3]), color=(255,0,0)) | |
cv2.imshow("LK", img) | |
cv2.waitKey(1) | |
except KeyboardInterrupt: | |
break | |
def predictBB(bb0, pt0, pt1): | |
if not pt0: | |
pt0 = pt1 | |
dx=[] | |
dy=[] | |
for p1, p2 in itertools.izip(pt0, pt1): | |
dx.append(p2[0]-p1[0]) | |
dy.append(p2[1]-p1[1]) | |
if not dx or not dy: | |
return bb0 | |
cen_dx = round(sum(dx)/len(dx)) | |
cen_dy = round(sum(dy)/len(dy)) | |
print cen_dx, cen_dy, | |
print "shift" | |
bb = [int(bb0[0]+cen_dx), int(bb0[1]+cen_dy), int(bb0[2]), int(bb0[3])] | |
if bb[0] <= 0: | |
bb[0] = 1 | |
if bb[1] <= 0: | |
bb[1] = 1 | |
return bb | |
lk() |
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Hey Jay,
I seem to get this issue,
0.0 0.0 shift
-20.0 14.0 shift
-18.0 30.0 shift
-35.0 17.0 shift
-44.0 18.0 shift
-58.0 97.0 shift
Traceback (most recent call last):
File "/media/mathew/d19f4260-bc8b-44b2-9209-1ed9bde9abfd/home/mat/Desktop/dddd.py", line 75, in
lk()
File "/media/mathew/d19f4260-bc8b-44b2-9209-1ed9bde9abfd/home/mat/Desktop/dddd.py", line 28, in lk
for i in xrange(len(pt)):
TypeError: object of type 'NoneType' has no len()