opencv_capture_jpg.py

import cv2
from datetime import datetime

def capture(opt):
    RESOLUTIONS = { "480p": [640, 480], "720p": [1280, 720], "1080p": [1920, 1080] }
    res = opt.get('resolution')
    filename = opt.get('filename')
    if res not in RESOLUTIONS.keys():
        raise RuntimeError('Invalid resolution: ' + res)
    cap = cv2.VideoCapture(opt.get('device_id'), cv2.CAP_V4L)
    cap.set(cv2.CAP_PROP_FRAME_WIDTH, RESOLUTIONS[res][0])
    cap.set(cv2.CAP_PROP_FRAME_HEIGHT, RESOLUTIONS[res][1])

    resp = None
    ret, frame = cap.read()
    if ret:
        cv2.imwrite(filename, frame)

    cap.release()
    #cv2.destroyAllWindows()
    return filename

if __name__ == "__main__":
    import argparse
    from datetime import datetime
    filename = datetime.now().strftime("%Y%m%d_%H%M%S.jpg")
    parser = argparse.ArgumentParser(description='Capture single image from USB webcam.')
    parser.add_argument('filename', nargs='?', default=filename)
    parser.add_argument('-i', '--device-id', type=int, default=0)
    parser.add_argument('-r', '--resolution', default="480p")
    opt = vars(parser.parse_args())
    resp = capture(opt)