motion_detection.py

#!/usr/bin/python

import  cv2
#      we are taking 3 frames 
def    imgdiff(x,y,z):
	img1=cv2.absdiff(x,y)
	img2=cv2.absdiff(y,z)
	com_diff=cv2.bitwise_and(img1,img2)
	return  com_diff

cap=cv2.VideoCapture(0)
#  taking 3 consistant frames
frame1=cap.read()[1]
frame2=cap.read()[1]
frame3=cap.read()[1]

#  converting  into grayscale
gray1=cv2.cvtColor(frame1,cv2.COLOR_BGR2GRAY)
gray2=cv2.cvtColor(frame2,cv2.COLOR_BGR2GRAY)
gray3=cv2.cvtColor(frame3,cv2.COLOR_BGR2GRAY)

while  cap.isOpened():
		#  passing arg to above function
		img_diff=imgdiff(gray1,gray2,gray3)
		#  showing diff
		cv2.imshow('diffimg',img_diff)
		# capturing new frames
		status,frame=cap.read()
		gray1=gray2
		gray2=gray3
		gray3=cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
		

		if  cv2.waitKey(1) &  0xFF  ==  ord('q'):
			break


cv2.destroyAllWindows()
cap.release()