window.cpp:366: error: (-215:Assertion failed) size.width>0 && size.height>0 in function 'cv::imshow'

Question

i work on hand detection with tensorflow api but when i extract the hand which in the drowning box get this error

args = parser.parse_args()
print(args.video_source)
cap = cv2.VideoCapture(0)
#cap.set(cv2.CAP_PROP_FRAME_WIDTH, args.width)
#cap.set(cv2.CAP_PROP_FRAME_HEIGHT, args.height)

start_time = datetime.datetime.now()
num_frames = 0
im_width, im_height = (cap.get(3), cap.get(4))
# max number of hands we want to detect/track
num_hands_detect = 2

cv2.namedWindow('Single-Threaded Detection', cv2.WINDOW_NORMAL)

while True:
    # Expand dimensions since the model expects images to have shape: [1, None, None, 3]
    ret, image_np = cap.read()
    image_np = cv2.flip(image_np, 1)
    try:
        image_np = cv2.cvtColor(image_np, cv2.COLOR_BGR2RGB)
    except:
        print("Error converting to RGB")

    # actual detection
    boxes, scores = detector_utils.detect_objects(
        image_np, detection_graph, sess)
    
    res= detector_utils.get_box_image(
        num_hands_detect, args.score_thresh, scores, boxes, im_width, im_height, image_np)

    # draw bounding boxes
    detector_utils.draw_box_on_image(
        num_hands_detect, args.score_thresh, scores, boxes, im_width, im_height, image_np)

    # Calculate Frames per second (FPS)
    num_frames += 1
    elapsed_time = (datetime.datetime.now() -
                    start_time).total_seconds()
    fps = num_frames / elapsed_time

    if (args.display > 0):
        # Display FPS on frame
        if (args.fps > 0):
            detector_utils.draw_fps_on_image(
                "FPS : " + str(int(fps)), image_np)

        cv2.imshow('Single-Threaded Detection', cv2.cvtColor(
            image_np, cv2.COLOR_RGB2BGR))
        cv2.imshow("b",res)
        if cv2.waitKey(25) & 0xFF == ord('q'):
            cv2.destroyAllWindows()
            break
    else:
        print("frames processed: ",  num_frames,
              "elapsed time: ", elapsed_time, "fps: ", str(int(fps)))

cv2.imshow("b",res)

error: OpenCV(3.4.6) D:\Build\OpenCV\opencv-

3.4.6\modules\highgui\src\window.cpp:366: error: (-215:Assertion failed)

size.width>0 && size.height>0 in function 'cv::imshow'

score 0 · Answer 1 · answered Jun 02 '19 at 19:21

0

this error in OpenCV generally means that the "res" variable that you send to cv2.imshow is a None for some reason, is this the case?

answered Jun 02 '19 at 19:21

T. Kelher

1,096
9
9

yes how can i solve it – Ahmed Sultan Jun 02 '19 at 19:39
is image_np also None? – T. Kelher Jun 02 '19 at 19:50
no it is run and make rectangle around the hand but when i write this line cv.imshow("b",res) the error is appear – Ahmed Sultan Jun 02 '19 at 19:58
yes, but it is due to res being None, now I'm wondering if image_np is also None, if this is not the case, then detector_utils.get_box_image most likely screws everything up – T. Kelher Jun 02 '19 at 20:11

window.cpp:366: error: (-215:Assertion failed) size.width>0 && size.height>0 in function 'cv::imshow'

1 Answers1