A simple example of using the Raspberry Pi Camera Module and python picamera for motion detection

raspberrypi-picamera-motion-detection.py

#!/usr/bin/python

import picamera
import cv2
import io
import numpy as np
import imutils


camera = picamera.PiCamera()

# Motion detection sensitivity
min_area = 100


def handle_new_frame(frame, past_frame, min_area):
    (h, w) = frame.shape[:2]
    r = 500 / float(w)
    dim = (500, int(h * r))
    frame = cv2.resize(frame, dim, cv2.INTER_AREA) # We resize the frame
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) # We apply a black & white filter
    gray = cv2.GaussianBlur(gray, (21, 21), 0) # Then we blur the picture

    # if the first frame is None, initialize it because there is no frame for comparing the current one with a previous one
    if past_frame is None:
        past_frame = gray
        return past_frame

    # check if past_frame and current have the same sizes
    (h_past_frame, w_past_frame) = past_frame.shape[:2]
    (h_current_frame, w_current_frame) = gray.shape[:2]
    if h_past_frame != h_current_frame or w_past_frame != w_current_frame: # This shouldnt occur but this is error handling
        print('Past frame and current frame do not have the same sizes {0} {1} {2} {3}'.format(h_past_frame, w_past_frame, h_current_frame, w_current_frame))
        return

    # compute the absolute difference between the current frame and first frame
    frame_detla = cv2.absdiff(past_frame, gray)
    # then apply a threshold to remove camera motion and other false positives (like light changes)
    thresh = cv2.threshold(frame_detla, 50, 255, cv2.THRESH_BINARY)[1]
    # dilate the thresholded image to fill in holes, then find contours on thresholded image
    thresh = cv2.dilate(thresh, None, iterations=2)
    cnts = cv2.findContours(thresh.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
    cnts = cnts[0] if imutils.is_cv2() else cnts[1]

    # loop over the contours
    for c in cnts:
        # if the contour is too small, ignore it
        if cv2.contourArea(c) < min_area:
            continue
        print("Motion detected!")

 
if __name__ == '__main__':
    camera.resolution = (640, 480)
    past_frame = None
    print("Starting motion detection")
    try:
        while True:
            stream = io.BytesIO()
            camera.capture(stream, format='jpeg', use_video_port=False)
            data = np.fromstring(stream.getvalue(), dtype=np.uint8)
            frame = cv2.imdecode(data, 1)
            if frame is not None:
                past_frame = handle_new_frame(frame, past_frame, min_area)
            else:
                print("No more frame")
    finally:
        print("Exiting")

getting a syntax error at line 25, any idea what's causing that?

same syntax error, line 25..

If you are having error on line 25, try to run the script with python 2.7..

 Line38       data2 = data1 . Shouldn't be data1 = data2 to get a new offset and not always comparing against the initial image in data1?