Mahotas – Local Maxima in Image

In this article we will see how we can find local maxima of the image in mahotas. Local maxima is basically local peaks in the image. 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.locmax method
Syntax : mahotas.locmax(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
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()

# getting local maxima of the image
new_img = mahotas.locmax(img)


# showing image
print("Local Maxima")
imshow(new_img)
show()

Output :

Image

Local Maxima

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()

# getting local maxima of the image
new_img = mahotas.locmax(img)


# showing image
print("Local Maxima")
imshow(new_img)
show()

Output :

Image

Local Maxima