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Mahotas – Closing Holes in Image
  • Last Updated : 10 Jul, 2020
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In this article we will see how we can close holes of the image in mahotas.  Closing holes means to remove the holes present in the image, closing is a process in which first dilation operation is performed and then erosion operation is performed. It eliminates the small holes from the obtained image, it is used for smoothening of contour and fusing of narrow breaks.

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.close_holes method



Syntax : mahotas.close_holes(img)

Argument : It takes image object 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
    
# loading iamge
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 Mehtod")
    
# showing image
imshow(img)
show()
   
  
# closing holes
new_img = mahotas.close_holes(img)
  
  
print("Closed Hole Image")
  
# showing image
imshow(new_img)
show()

Output :



Image threshold using Otsu Mehtod

Lena Otsu

Closed Hole Image

Close Holes

Another example

Python3




# importing required libraries
import mahotas
import numpy as np
from pylab import gray, imshow, show
import os
   
# loading iamge
img = mahotas.imread('dog_image.png')
  
# fltering 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 Mehtod")
    
# showing image
imshow(img)
show()
    
  
# closing holes
new_img = mahotas.close_holes(img)
  
  
print("Closed Hole Image")
  
# showing image
imshow(new_img)
show()

Output :

Image threshold using Otsu Mehtod

Closed Hole Image

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