#Shift all pixels left a few spaces...
#See slide number 21 from IrfanEssa-CP-02-5-Filtering.pdf

#
# Jay Summet 2015
#
#Python 2.7, OpenCV 2.4.x
#

import cv2
import numpy as np


#Linux window/threading setup code.
cv2.startWindowThread()
cv2.namedWindow("Original")
cv2.namedWindow("Shifted")

#Load source / input image as grayscale, also works on color images...
imgIn = cv2.imread("oscar.jpg", cv2.IMREAD_GRAYSCALE)
cv2.imshow("Original", imgIn)


#Create the identity filter, but with the 1 shifted to the right!
kernel = np.zeros( (9,9), np.float32)
kernel[4,7] = 1.0   #Identity, shifted right!


#cv2.BORDER_CONSTANT default to black. Without this borderType specified,
#it will default to something else, probably replicate or reflect...
#and that makes it very hard to see the effect with only a 2 pixel shift...

custom = cv2.filter2D(imgIn, -1, kernel, borderType = cv2.BORDER_CONSTANT)
cv2.imshow("Shifted", custom)


cv2.waitKey(0)