search-image.py

#!/usr/bin/env python3

# version 0.3.2
#
# find the image_to_find inside the target_image, if found optionally mark a rectangle on markfile

# Example 1:
# search-image.py examples/100-orig.png examples/menu_hamburger.png

# Example 2:
# copy examples/100-orig.png marked_result.png
# search-image.py examples/100-orig.png examples/menu_hamburger.png marked_result.png

# http://stackoverflow.com/questions/4720168/image-in-image-algorithm

import sys, subprocess, cv2
from PIL import Image, ImageDraw

if len (sys.argv) > 2:
   print (sys.argv[1], sys.argv[2])
   target_image = sys.argv[1]
   image_to_find = sys.argv[2]
else:
   print ('Specify target image, followed by the image to search for.')
   print ('Example: search-image.py target_image.png image_to_find.png [markfile.png]')
   sys.exit ()

im = cv2.imread (target_image)
tmp = cv2.imread (image_to_find)

image_size = im.shape[:2]
template_size = tmp.shape[:2]

print ('image_size (y,x)', image_size)
print ('template_size (y,x)', template_size)

# CV_TM_SQDIFF is the match method, smaller min_val means better match. min_loc is the best match location
# with other matching methods you need to look at max_val and max_loc
# http://opencv.itseez.com/doc/tutorials/imgproc/histograms/template_matching/template_matching.html
# http://docs.opencv.org/doc/tutorials/imgproc/histograms/template_matching/template_matching.html

result = cv2.matchTemplate (im, tmp, cv2.TM_SQDIFF)

min_val, max_val, min_loc, max_loc = cv2.minMaxLoc (result)

print ('min_val', min_val)
print ('max_val', max_val)
print ('min_loc', min_loc, 'X')
print ('max_loc', max_loc)

confidence = (9999999999 - min_val) / 100000000
print ('primary confidence', '%.2f %%' % confidence)

altconfidence = 100 - ((min_val / max_val) * 100)
print ('alternate confidence', '%.2f %%' % altconfidence)

topleftx = min_loc[0]
toplefty = min_loc[1]
sizex = template_size[1]
sizey = template_size[0]

if (altconfidence > 99) \
   or (confidence > 97 and altconfidence > 93) \
   or (confidence > 95.7 and altconfidence > 96.3):
   print ('The image of size', template_size, '(y,x) was found at', min_loc)
   if (len(sys.argv) > 3):
      print ('Marking', sys.argv[3], 'with a red rectangle')
      marked = Image.open(sys.argv[3])
      draw = ImageDraw.Draw(marked)
      draw.line(((topleftx,         toplefty),         (topleftx + sizex, toplefty)),           fill="red", width=2)
      draw.line(((topleftx + sizex, toplefty),         (topleftx + sizex, toplefty + sizey)),   fill="red", width=2)
      draw.line(((topleftx + sizex, toplefty + sizey), (topleftx,         toplefty + sizey)),   fill="red", width=2)
      draw.line(((topleftx,         toplefty + sizey), (topleftx,         toplefty)),           fill="red", width=2)
      del draw 
      marked.save(sys.argv[3], "PNG")
else:
   print ('The image was not found')