Python, OpenCV, Raspberry Pi-3 - Attribute Error - 'NoneType' object -

i trying track green ball v2 camera module using opencv , python (using virtualenv), keep encountering attributeerror: 'nonetype' object has no attribute 'shape'

any appreciated!

traceback (most recent call last):

 file "/home/pi/ball-track/ball_tracking.py", line 52, in <module>   frame = imutils.resize(frame, width=600)   file "/usr/local/lib/python2.7/dist-packages/imutils/convenience.py", line 45, in resize     (h, w) = image.shape[:2] attributeerror: 'nonetype' object has no attribute 'shape' 

i have tried add bit of code in amend error not work:

while true:     grabbed, frame = camera.read()      if not grabbed:         continue      # rest of program 

i have video file trying use within script , contains desired object (to tracked)

here code:

# python ball_tracking.py --video ball_tracking_example.mp4 # python ball_tracking.py  # import necessary packages collections import deque import numpy np import argparse import imutils import cv2  # construct argument parse , parse arguments ap = argparse.argumentparser() ap.add_argument("-v", "--video",     help="path (optional) video file") ap.add_argument("-b", "--buffer", type=int, default=64,     help="max buffer size") args = vars(ap.parse_args())  # define lower , upper boundaries of "green" # ball in hsv color space, initialize # list of tracked points greenlower = (29, 86, 6) greenupper = (64, 255, 255) pts = deque(maxlen=args["buffer"])  # if video path not supplied, grab reference # webcam if not args.get("video", false):     camera = cv2.videocapture(0)  # otherwise, grab reference video file else:     camera = cv2.videocapture(args["video"])  # keep looping while true:     # grab current frame     (grabbed, frame) = camera.read()      # if viewing video , did not grab frame,     # have reached end of video     if args.get("video") , not grabbed:         break      # resize frame, blur it, , convert hsv     # color space     frame = imutils.resize(frame, width=600)     # blurred = cv2.gaussianblur(frame, (11, 11), 0)     hsv = cv2.cvtcolor(frame, cv2.color_bgr2hsv)      # construct mask color "green", perform     # series of dilations , erosions remove small     # blobs left in mask     mask = cv2.inrange(hsv, greenlower, greenupper)     mask = cv2.erode(mask, none, iterations=2)     mask = cv2.dilate(mask, none, iterations=2)      # find contours in mask , initialize current     # (x, y) center of ball     cnts = cv2.findcontours(mask.copy(), cv2.retr_external,         cv2.chain_approx_simple)[-2]     center = none      # proceed if @ least 1 contour found     if len(cnts) > 0:         # find largest contour in mask, use         # compute minimum enclosing circle ,         # centroid         c = max(cnts, key=cv2.contourarea)         ((x, y), radius) = cv2.minenclosingcircle(c)         m = cv2.moments(c)         center = (int(m["m10"] / m["m00"]), int(m["m01"] / m["m00"]))          # proceed if radius meets minimum size         if radius > 10:             # draw circle , centroid on frame,             # update list of tracked points             cv2.circle(frame, (int(x), int(y)), int(radius),                 (0, 255, 255), 2)             cv2.circle(frame, center, 5, (0, 0, 255), -1)      # update points queue     pts.appendleft(center)      # loop on set of tracked points     in xrange(1, len(pts)):         # if either of tracked points none, ignore         # them         if pts[i - 1] none or pts[i] none:             continue          # otherwise, compute thickness of line ,         # draw connecting lines         thickness = int(np.sqrt(args["buffer"] / float(i + 1)) * 2.5)         cv2.line(frame, pts[i - 1], pts[i], (0, 0, 255), thickness)      # show frame our screen     cv2.imshow("frame", frame)     key = cv2.waitkey(1) & 0xff      # if 'q' key pressed, stop loop     if key == ord("q"):         break  # cleanup camera , close open windows camera.release() cv2.destroyallwindows() 

for experiencing same issue have resolved error typing command:

  sudo modprobe bcm2835-v4l2  

works charm!