How to Resize an Image in OpenCV Using Python?

Image resizing is a common task in computer vision, where it is required to change the size of an image. Image resizing can be accomplished in OpenCV using the Python programming language. In this article, we will discuss how to resize an image in OpenCV using Python.

Introduction to OpenCV

OpenCV, or Open Source Computer Vision Library, is an open-source library that allows to process images and video streams. OpenCV was originally developed in 1999 by Intel, and now it is supported by several organizations, including Google and NVIDIA.

Basic Concepts

Before proceeding to image resizing, let’s discuss some basic concepts in OpenCV:

Image Representation

In OpenCV, an image is represented by a two-dimensional matrix with each pixel containing a value that represents its color. There are three color channels in an image: Red, Green, and Blue. The value of each pixel in these channels determines the color of the pixel.

Image Resizing

Image resizing is a process of changing the size of an image. Resizing can be done by reducing or increasing the size of the image.

Resizing an Image in OpenCV using Python

Resizing an image in OpenCV can be done using the resize() function. The function takes two arguments: the original image and the desired size of the image.

Here is a sample code to resize an image in OpenCV using Python:

import cv2

# load the image
image = cv2.imread('lena.jpg')

# get the height and width of the image
height, width = image.shape[:2]

# define a new size for the image
new_size = (int(width/2), int(height/2))

# resize the image
resized_image = cv2.resize(image, new_size)

# display the original and the resized images
cv2.imshow('Original Image', image)
cv2.imshow('Resized Image', resized_image)

# wait for a key press and then close all windows
cv2.waitKey()
cv2.destroyAllWindows()

In the above code, we first load an image using the imread() function. Then we get the height and width of the image. Next, we define a new size for the image by dividing the original size by 2. Finally, we resize the image using the resize() function and display both original and resized images using the imshow() function.

Conclusion

In this article, we discussed how to resize an image in OpenCV using Python. Resizing an image is a common task in computer vision, and it can be accomplished easily in OpenCV. The resize() function is used for resizing an image, and it takes two arguments – the original image and the desired size of the image. I hope this article helps you to resize images using OpenCV and Python.