motion.py

'''
This is a heavily cut and slightly modified version of code I found:
http://www.noah.org/wiki/movement.py  (version 3), which
has a license here:

AUTHOR

    Noah Spurrier <noah@noah.org>

LICENSE

    This license is approved by the OSI and FSF as GPL-compatible.
        http://opensource.org/licenses/isc-license.txt

    Copyright (c) 2015, Noah Spurrier
    PERMISSION TO USE, COPY, MODIFY, AND/OR DISTRIBUTE THIS SOFTWARE FOR ANY
    PURPOSE WITH OR WITHOUT FEE IS HEREBY GRANTED, PROVIDED THAT THE ABOVE
    COPYRIGHT NOTICE AND THIS PERMISSION NOTICE APPEAR IN ALL COPIES.
    THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
    MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

VERSION

    Version 3

'''


import cv2

def delta_images(t0, t1, t2):
    d1 = cv2.absdiff(t2, t0)
    return d1

def motion_detection(t_minus, t_now, t_plus):
    delta_view = delta_images(t_minus, t_now, t_plus)
    retval, delta_view = cv2.threshold(delta_view, 16, 255, 3)
    cv2.normalize(delta_view, delta_view, 0, 255, cv2.NORM_MINMAX)
    img_count_view = cv2.cvtColor(delta_view, cv2.COLOR_RGB2GRAY)
    delta_count = cv2.countNonZero(img_count_view)
    dst = cv2.addWeighted(screen,1.0, delta_view,0.6,0)
    delta_count_last = delta_count
    return delta_count