Get frame from webcam and display it in real time

live_webcam.py

"""
    Get frame from webcam and display it in real time

    OpenCv version: 3.4.1
    Installed with command: pip install opencv-python
    Python version: 3.6.5 :: Anaconda, Inc.
"""
import cv2

"""
    config(dict): configuration window and camera to display frames in real time

    Param:
        window
            name(string): string title of window that frames are displayed
            width(int): initial window width
            height(int): initial window height
            x0(int): initial window x position on screen(display reference is corner left)
            y0(int): initial window y position on screen(display reference is corner left)
        camera
            index(int): usb camera index
            width(int): frame width acquired from camera
            height(int): frame height acquired from camera
            fps(int): frame rate acquisition
"""
config = {
    'window': {
        'name': 'live webcam',
        'width': 640,
        'height': 480,
        'x0': 0,
        'y0': 0
    },
    'camera': {
        'index': 0,
        'width': 640,
        'height': 480,
        'fps': 60
    }
}

# open camera
camera = cv2.VideoCapture(config['camera']['index'])

# check camera is open
if not camera.isOpened():
    print("Error when try to open camera")
    exit(-1)

# set frame width and height acquired from camera
camera.set(cv2.CAP_PROP_FRAME_WIDTH, config['camera']['width'])
camera.set(cv2.CAP_PROP_FRAME_HEIGHT, config['camera']['height'])

# set initial window size and position
cv2.namedWindow(config['window']['name'], cv2.WINDOW_NORMAL)
cv2.resizeWindow(config['window']['name'], config['window']
                 ['width'], config['window']['height'])
cv2.moveWindow(config['window']['name'], config['window']
               ['x0'], config['window']['y0'])

# real time frame display on window
while True:
    # acquire image
    ret, frame = camera.read()

    # check if acquisition is OK
    if not ret:
        print("Error when try to capture frame from webcam")
        break

    # display image
    cv2.imshow(config['window']['name'], frame)

    # check if key 'q' are pressed
    if cv2.waitKey(1000//config['camera']['fps']) & 0xFF == ord('q'):
        break

# destroy created window
cv2.destroyWindow(config['window']['name'])