Mahotas – Eccentricity of Image

In this article we will see how we can get the eccentricity of the image in mahotas. Eccentricity measures the shortest length of the paths from a given vertex v to reach any other vertex w of a connected graph. Computed for every vertex v it transforms the connectivity structure of the graph into a set of values. For a connected region of a digital image it is defined through its neighbourhood graph and the given metric. 

mahotas.demos.load('lena')

Below is the lena image 

In order to do this we will use mahotas.features.eccentricity( method
Syntax : mahotas.features.eccentricity(img)
Argument : It takes image object as argument
Return : It returns float value 

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()

# computing eccentricity value
value = mahotas.features.eccentricity(img)


# showing value
print("Eccentricity value = " + str(value))

Output :

Image

Eccentricity value = 0.0

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()

# computing eccentricity value
value = mahotas.features.eccentricity(img)


# showing value
print("Eccentricity value = " + str(value))

Output :

Image

Eccentricity value = 0.7950893156644899