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from PIL import Image
from numpy import *
from pylab import *
from scipy import ndimage


    

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import cv2


    

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cap = cv2.VideoCapture(-1)


    

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ret, im = cap.read()
print ret


    

    




True

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while True:
    ret, im = cap.read()
    if not ret:
        break
    cv2.imshow('video', im)
    key = cv2.waitKey(10)
    if key == 27:
        break
cv2.destroyAllWindows()


    

In [78]:

    

# Parameters
lk_params = dict(winSize=(15, 15), maxLevel=2,
                criteria=(cv2.TERM_CRITERIA_EPS | cv2.TERM_CRITERIA_COUNT, 10, 0.03))
subpix_params = dict(zeroZone=(-1, -1), winSize=(10, 10), 
                     criteria=(cv2.TERM_CRITERIA_COUNT | cv2.TERM_CRITERIA_EPS, 20, 0.03))
feature_params = dict(maxCorners=500, qualityLevel=0.01, minDistance=10)
cycle = 20
draw_flow = True

# Initialize
nbr_fetures = 0
prev = []
features = []
tracks = []
count = 0
while True:
    ret, im = cap.read()
    if not ret:
        print "Image Capture Error"
        break
    image = im.copy()
    if prev!=[]:
        # for the first frame or after reset, detect points
        if features==[]:
            features = cv2.goodFeaturesToTrack(prev, **feature_params)
            cv2.cornerSubPix(prev, features, **subpix_params)
            tracks = [[p] for p in features.reshape((-1, 2))]
            nbr_fetures = len(features)
        
        # find the features in the new frame
        img_gray = cv2.cvtColor(im, cv2.COLOR_BGR2GRAY)
        tmp = float32(features). reshape(-1, 1, 2)
        fs, status, track_error = cv2.calcOpticalFlowPyrLK(prev, img_gray, tmp, None, **lk_params)
        features = [p for (st, p) in zip(status, fs) if st]
        fs = array(fs).reshape((-1, 2))
        for i, f in enumerate(fs):
            tracks[i].append(f)
        ndx = [i for (i, st) in enumerate(status) if not st]
        ndx.reverse()
        for i in ndx:
            tracks.pop(i)
        prev = img_gray
        
        for point in features:
            cv2.circle(image, (int(point[0][0]), int(point[0][1])), 3, (0, 255, 0), -1)
        if draw_flow:
            for t in tracks:
                cv2.line(image, tuple(t[-1]), tuple(t[-2]), (0, 0, 255))
    else:
        prev = cv2.cvtColor(im, cv2.COLOR_BGR2GRAY)
    cv2.imshow('video', image)
    key = cv2.waitKey(10)
    if key == 27:
        break
    count += 1
    if (count>=cycle or len(features)<nbr_fetures/2 or key==ord(' ')):
        count = 0
        features = []
cv2.destroyAllWindows()


    

    




/usr/local/lib/python2.7/dist-packages/ipykernel_launcher.py:22: DeprecationWarning: elementwise != comparison failed; this will raise an error in the future.

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