Mahotas – Template Matching

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In this article we will see how we can do template matching in mahotas. Template is basically a part or structure of image. In this tutorial we will use “lena” image, below is the command to load it.

mahotas.demos.load('lena')

Below is the lena image

In order to do this we will use mahotas.template_match method
Syntax : mahotas.template_match(img, template)
Argument : It takes image object and template as argument
Return : It returns image object

Note : Input image should be filtered or should be loaded as grey
In order to filter the image we will take the image object which is numpy.ndarray and filter it with the help of indexing, below is the command to do this

image = image[:, :, 0]

Below is the implementation

Python3

# importing required libraries
import mahotas
import mahotas.demos
from pylab import gray, imshow, show
import numpy as np
import matplotlib.pyplot as plt
   
# loading image
img = mahotas.demos.load('lena')
   
# filtering image
img = img.max(2)
 
print("Image")
   
# showing image
imshow(img)
show()
 
# template
template = np.array([
            [1, 1, 1],
            [1, 1, 1],
            [1, 1, 1]], bool)
 
# matching template
new_img = mahotas.template_match(img, template)
  
 
# showing image
print("Matched Image")
imshow(new_img)
show()

Output :

Image

Matched Image

Another example

Python3

# importing required libraries
import mahotas
import numpy as np
from pylab import gray, imshow, show
import os
import matplotlib.pyplot as plt
  
# loading image
img = mahotas.imread('dog_image.png')
 
 
# filtering image
img = img[:, :, 0]
   
print("Image")
   
# showing image
imshow(img)
show()
# template
template = np.array([
            [1, 1, 1],
            [1, 1, 1],
            [1, 1, 1]], bool)
 
# matching template
new_img = mahotas.template_match(img, template)
  
 
# showing image
print("Matched Image")
imshow(new_img)
show()