In this article, we will see how we can get the euler number of the image in mahotas. The Euler number is a measure of the topology of an image. It is defined as the total number of objects in the image minus the number of holes in those objects. You can use either 4- or 8-connected neighborhoods.
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.euler method
Syntax : mahotas.euler(img)
Argument : It takes image object as argument
Return : It returns integer
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
# importing required libraries import mahotas
import mahotas.demos
from pylab import gray, imshow, show
import numpy as np
# loading image img = mahotas.demos.load( 'lena' )
# filtering image img = img. max ( 2 )
# otsu method T_otsu = mahotas.otsu(img)
# image values should be greater than otsu value img = img > T_otsu
print ( "Image threshold using Otsu Method" )
# creating a labeled image marker, n_nucleus = mahotas.label(img)
# showing image imshow(img) show() # euler number of image of image euler = mahotas.euler(img)
print ( "Euler Number of Image : " + str (euler))
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Output :
Image threshold using Otsu Method
Euler Number of Image : 54.25
Another example
# importing required libraries import mahotas
import numpy as np
from pylab import gray, imshow, show
import os
# loading image img = mahotas.imread( 'dog_image.png' )
# filtering image img = img[:, :, 0 ]
# otsu method T_otsu = mahotas.otsu(img)
# image values should be greater than otsu value img = img > T_otsu
print ( "Image threshold using Otsu Method" )
# showing image imshow(img) show() # euler number of image of image euler = mahotas.euler(img)
print ( "Euler Number of Image : " + str (euler))
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Output :
Image threshold using Otsu Method
Euler Number of Image : 76.75