Python OpenCV example (2.3.1) - matchTemplate

matchTemplate_example.py

import cv2
from cv2 import cv

method = cv.CV_TM_SQDIFF_NORMED

template_name = "mozicon128.png"
image_name = "test2.jpeg"

# Load
needle = cv2.imread(template_name)
haystack = cv2.imread(image_name)

# Convert to gray:
needle_g = cv2.cvtColor(needle, cv2.CV_32FC1) 

haystack_g = cv2.cvtColor(haystack, cv2.CV_32FC1) 

# Attempt match
d = cv2.matchTemplate(needle_g, haystack_g, cv2.cv.CV_TM_SQDIFF_NORMED)
 
# we want the minimum squared difference
mn,_,mnLoc,_ = cv2.minMaxLoc(d)

# Print it, for comparison
print mn

# Draw the rectangle
MPx,MPy = mnLoc

trows,tcols = needle_g.shape[:2]

# Normed methods give better results, ie matchvalue = [1,3,5], others sometimes shows errors
cv2.rectangle(haystack, (MPx,MPy),(MPx+tcols,MPy+trows),(0,0,255),2)

cv2.imshow('output',haystack)

cv2.waitKey(0)
import sys
sys.exit(0)