# BAD EXAMPLE!
#
#This bad code shows the problems with underflow/overflow that result
# if you do math with 8 bit images...
#
# Jay Summet - Summer 2015
#
# Python 2.7, OpenCV 2.4.x
import cv2

a = cv2.imread("a.jpg")
b = cv2.imread("b.jpg")

#Doing math with uint8 images will suffer from overflow and underflow!
#Pure subtraction:
c = a-b

cv2.imshow("pure subtract", c)
cv2.waitKey(0)

c = a+b
cv2.imshow("add", c)
cv2.waitKey(0)

c = a+b/2
cv2.imshow("avg", c)
cv2.waitKey(0)