capture_camera.py

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# Example : capture an image from an attached camera

# Author : Toby Breckon, toby.breckon@durham.ac.uk

# Copyright (c) 2015 School of Engineering & Computing Science,
#                    Durham University, UK
# License : LGPL - http://www.gnu.org/licenses/lgpl.html

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import numpy as np
import cv2
import sys

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camera_to_use = 1; # 0 if you have one camera, 1 or > 1 otherwise

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# define video capture object

cap = cv2.VideoCapture();

# define display window name

windowName = "Live Camera Input"; # window name

# open camera device (and check it worked)

if not(cap.open(camera_to_use)):
    print("Cannot open camera - check connection and operation as suggested.");
    sys.exit;

# read an image from the camera

ret, frame = cap.read();

# to avoid the black/blank first frame from many cameras
# with some (not all) cameras you need to read the first frame twice (first frame only)

ret, frame = cap.read();

# check it has loaded

if not frame is None:

    # create window by name (as resizable)

    cv2.namedWindow(windowName, cv2.WINDOW_NORMAL);

    # display image

    cv2.imshow(windowName,frame);

    # start the event loop - essential
    # wait indefinitely for any key press

    cv2.waitKey(0);

else:
    print("No image successfully loaded from camera.")

# close all windows

cv2.destroyAllWindows()

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