Non-Distorted Image Resizing with OpenCV

Introduction

When we resize an image, we usually want to maintain its aspect ratio and avoid any distortion. In this article, we will discuss how to achieve non-distorted image resizing using OpenCV.

Resizing an Image with OpenCV

The OpenCV library provides a function called resize() which can be used to resize an image. However, if we simply use this function, it may result in a distorted image. To avoid distortion, we need to use the correct interpolation method.

Interpolation Methods

Interpolation is the method used to estimate the color of a pixel after resizing an image. OpenCV provides various interpolation methods, including:

• cv2.INTER_NEAREST: Nearest neighbor interpolation, which simply takes the value of the nearest pixel.
• cv2.INTER_LINEAR: Bilinear interpolation, which takes a weighted average of the four nearest pixels.
• cv2.INTER_CUBIC: Bicubic interpolation, which takes a weighted average of the 16 nearest pixels.
• cv2.INTER_LANCZOS4: Lanczos interpolation, which takes a weighted average of the 8 nearest pixels.

Non-Distorted Resizing

To achieve non-distorted resizing, we need to use the correct interpolation method. In most cases, cv2.INTER_LINEAR is a good choice, as it provides a good balance between speed and quality. However, if we need higher quality, we can use cv2.INTER_CUBIC or cv2.INTER_LANCZOS4, although these methods are slower.

Example Code

Here is an example code snippet that demonstrates how to achieve non-distorted resizing using OpenCV:

import cv2

# Load an image
img = cv2.imread("image.jpg")

# Set the new size
new_size = (640, 480)

# Resize the image using bilinear interpolation
resized_img = cv2.resize(img, new_size, interpolation=cv2.INTER_LINEAR)

In this example, we first load an image using cv2.imread(). We then set the new size using a tuple, and finally, we resize the image using cv2.resize() with cv2.INTER_LINEAR as the interpolation method.

Conclusion

In conclusion, non-distorted image resizing can be achieved using OpenCV by selecting the correct interpolation method. By using cv2.INTER_LINEAR, cv2.INTER_CUBIC, or cv2.INTER_LANCZOS4, we can resize images while maintaining their aspect ratio and avoiding distortion.