フレーム差分により動体検知をする

motion_detect.py

import cv2
import sys
import os
import subprocess

def detect_motion(cap):
    avg = None
    while(cap.isOpened()):
        ret, frame = cap.read()
        frame = cv2.flip(frame, -1) #カメラ上下左右反転
        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
        if avg is None:
            avg = gray.copy().astype('float')
            continue

        #加重平均
        cv2.accumulateWeighted(gray, avg, 0.5)
        frameDelta = cv2.absdiff(gray, cv2.convertScaleAbs(avg))
        thresh = cv2.threshold(frameDelta, 3, 255, cv2.THRESH_BINARY)[1]

        image, contours, hierarchy = cv2.findContours(thresh.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
        max_area = 0
        target = contours[0]
        for cnt in contours:
            #輪郭の面積を求めてくれるcontourArea
            area = cv2.contourArea(cnt)
            if max_area < area and area < 10000 and area > 1000:
                max_area = area;
                target = cnt

        if max_area > 1000:
            break
    else:
        cap.release()
        #sys.exit(1)

def main():
    while(True):
        cap = cv2.VideoCapture(0)
        cap.set(3,640) # set Width
        cap.set(4,480) # set Height
        detect_motion(cap)
        print('hit! motion!')

        cap.release()

if __name__ == '__main__':
    main()