In this article, we will see how we can do convolution of the image in mahotas. Convolution is a simple mathematical operation which is fundamental to many common image processing operators. Convolution provides a way of `multiplying together’ two arrays of numbers, generally of different sizes, but of the same dimensionality, to produce a third array of numbers of the same dimensionality.
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.convolve method
Syntax : mahotas.convolve(img, weight)
Argument : It takes image object and numpy nd array objectas 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 librariesimport mahotasimport mahotas.demosfrom pylab import gray, imshow, showimport numpy as np # loading imageimg = mahotas.demos.load('lena') # filtering imageimg = img.max(2)# otsu methodT_otsu = mahotas.otsu(img) # image values should be greater than otsu valueimg = img > T_otsu print("Image threshold using Otsu Method") # showing imageimshow(img)show() # weightweight = np.ones((5, 5), float)# convolving imagenew_img = mahotas.convolve(img, weight)print("Convolved Image")# showing imageimshow(new_img)show() |
Output :
Image threshold using Otsu Method
Convolved Image
Another example
Python3
# importing required librariesimport mahotasimport numpy as npfrom pylab import gray, imshow, showimport os # loading imageimg = mahotas.imread('dog_image.png')# filtering imageimg = img[:, :, 0] # otsu methodT_otsu = mahotas.otsu(img) # image values should be greater than otsu valueimg = img > T_otsu print("Image threshold using Otsu Method") # showing imageimshow(img)show() # weightweight = np.ones((5, 5), float)# convolving imagenew_img = mahotas.convolve(img, weight)print("Convolved Image")# showing imageimshow(new_img)show() |
Output :
Image threshold using Otsu Method
Convolved Image
