Erosion and Dilation of images using OpenCV in python
Morphological operations are a set of operations that process images based on shapes. They apply a structuring element to an input image and generate an output image.
The most basic morphological operations are two: Erosion and Dilation
Basics of Erosion:
- Erodes away the boundaries of the foreground object
- Used to diminish the features of an image.
Working of erosion:
- A kernel(a matrix of odd size(3,5,7) is convolved with the image.
- A pixel in the original image (either 1 or 0) will be considered 1 only if all the pixels under the kernel are 1, otherwise, it is eroded (made to zero).
- Thus all the pixels near the boundary will be discarded depending upon the size of the kernel.
- So the thickness or size of the foreground object decreases or simply the white region decreases in the image.
Basics of dilation:
- Increases the object area
- Used to accentuate features
Working of dilation:
- A kernel(a matrix of odd size(3,5,7) is convolved with the image
- A pixel element in the original image is ‘1’ if at least one pixel under the kernel is ‘1’.
- It increases the white region in the image or the size of the foreground object increases
- Python
# Python program to demonstrate erosion and # dilation of images. import cv2 import numpy as np # Reading the input image img = cv2.imread( 'input.png' , 0 ) # Taking a matrix of size 5 as the kernel kernel = np.ones(( 5 , 5 ), np.uint8) # The first parameter is the original image, # kernel is the matrix with which image is # convolved and third parameter is the number # of iterations, which will determine how much # you want to erode/dilate a given image. img_erosion = cv2.erode(img, kernel, iterations = 1 ) img_dilation = cv2.dilate(img, kernel, iterations = 1 ) cv2.imshow( 'Input' , img) cv2.imshow( 'Erosion' , img_erosion) cv2.imshow( 'Dilation' , img_dilation) cv2.waitKey( 0 ) |
The second image is the eroded form of the original image and the third image is the dilated form.
Last Updated on November 13, 2021 by admin