find_image.py

import sys
#import time
import numpy
from PIL import Image

def find_image(png_big, png_small):
  arr_big = numpy.array(png_big)
  arr_small = numpy.array(png_small)
  if len(arr_big) < len(arr_small):
    return [-2,-2] # unable to search a bigger picture in a smaller picture
  total = len(arr_small) * len(arr_small[0])
  for y_big in range(0, len(arr_big)-len(arr_small)):
    for x_big in range(0, len(arr_big[y_big])-len(arr_small[0])):
      found = 0
      for y_small in range(0, len(arr_small)):
        for x_small in range(0, len(arr_small[0])):
          a = x_big + x_small
          b = y_big + y_small
          p = x_small
          q = y_small
          #print('BIG={0},{1} SMALL={2},{3}'.format(a,b,p,q))
          #time.sleep(0.1)
          pixel_big = arr_big[b][a]
          pixel_small = arr_small[q][p]
          if not isinstance(pixel_big,numpy.uint8):
            pixel_big = list(arr_big[b][a])
            pixel_small = list(arr_small[q][p])
          if pixel_big != pixel_small:
            break # mismatch
          else:
            found = found + 1
            if found == total:
              # print('TOP LEFT x={0},y={1}'.format(x_big,y_big))
              return [x_big,y_big]
  return [-1,-1] # not found


png_big = Image.open(sys.argv[1])
png_small = Image.open(sys.argv[2])
print('top left = {0}'.format(find_image(png_big,png_small)))