In this article we will see how we can do stretching for RGB image in mahotas. Contrast stretching (often called normalization) is a simple image enhancement technique that attempts to improve the contrast in an image by `stretching’ the range of intensity values it contains to span a desired range of values, e.g. the full range of pixel values that the image type concerned allows. RGB stretching is variation of stretch() function that works per-channel on an RGB 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.regmin method
Syntax : mahotas.stretch_rgb(img)
Argument : It takes image object as argument
Return : It returns image object
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' ) print ( "Image" ) # showing image imshow(img) show() # stretching rgb image new_img = mahotas.stretch_rgb(img) # Stretched image print ( "Stretched Image" ) imshow(new_img) show() |
Output :
Image
Stretched Image
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' ) print ( "Image" ) # showing image imshow(img) show() # stretching image new_img = mahotas.stretch_rgb(img) # Stretched image print ( "Stretched Image" ) imshow(new_img) show() |
Output :
Image
Stretched Image