capture_cv2.py

import cv2
import numpy as np

# create video capture
cap = cv2.VideoCapture(0)

imwidth=cap.get(cv2.cv.CV_CAP_PROP_FRAME_WIDTH)  
imheight=cap.get(cv2.cv.CV_CAP_PROP_FRAME_HEIGHT)  
print 'img width %d height %d ' % (imwidth,imheight) 

while(1):
    # read the frames
    _,frame = cap.read()

    # smooth it
    frame = cv2.blur(frame,(30,3))

    # convert to hsv and find range of colors
    hsv = cv2.cvtColor(frame,cv2.COLOR_BGR2HSV)
    thresh = cv2.inRange(hsv,np.array((0, 80, 80)), np.array((20, 255, 255)))
    thresh2 = thresh.copy()

    # find contours in the threshold image
    contours,hierarchy = cv2.findContours(thresh,cv2.RETR_LIST,cv2.CHAIN_APPROX_SIMPLE)

    # finding contour with maximum area and store it as best_cnt
    max_area = 0
    
    for cnt in contours:
        area = cv2.contourArea(cnt)
        
        if area > max_area:
            max_area = area
            best_cnt = cnt

    # finding centroids of best_cnt and draw a circle there
    # //M = cv2.moments(best_cnt)
    # //cx,cy = int(M['m10']/M['m00']), int(M['m01']/M['m00'])
    # //cv2.circle(frame,(cx,cy),5,255,-1)

    # Show it, if key pressed is 'Esc', exit the loop
    imgsize = frame.shape
    simg = cv2.resize(frame,(imgsize[1]/2,imgsize[0]/2))
    cv2.imshow('frame',simg)
    #cv2.imshow('thresh',thresh2)
    if cv2.waitKey(33)== 27:
        break

# Clean up everything before leaving
cv2.destroyAllWindows()
cap.release()