Mahotas – Opening Process on Image

Last Updated : 29 Jul, 2021

In this article we will see how we can perform opening on the image in mahotas. Opening is a process in which first erosion operation is performed and then dilation operation is performed. It eliminates the thin protrusions of the obtained image and it is used for removing internal noise of the obtained image.

In this tutorial we will use “luispedro” image, below is the command to load it.

mahotas.demos.load('luispedro')

Below is the luispedro image

In order to do this we will use mahotas.morph.openmethod

Syntax : mahotas.morph.open(image)
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 image
luispedro = mahotas.demos.load('luispedro')
  
# filtering image
luispedro = luispedro.max(2)
  
# otsu method
T_otsu = mahotas.otsu(luispedro)
   
# image values should be greater than otsu value
img = luispedro > T_otsu
  
print("Image threshold using Otsu Method")
  
# showing image
imshow(img)
show()
 
# opening image
new_img = mahotas.morph.open(img)
  
# showing new image
print("Opened Image")
imshow(new_img)
show()

Output :

Image threshold using Otsu Method

Opened Image

Another example

Python3

# importing required libraries
import mahotas
import numpy as np
import matplotlib.pyplot as plt
import os
  
# loading image
img = mahotas.imread('dog_image.png')
       
# setting filter to the 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()
 
# opening image
new_img = mahotas.morph.open(img)
  
# showing new image
print("Opened Image")
imshow(new_img)
show()