Create Border around Images in OpenCV

Adding a border around an image can be useful in many scenarios, such as padding, visualization, or separating images. OpenCV provides a simple way to achieve this using the copyMakeBorder() function. This function allows you to create different types of borders, including constant-colored borders and replicated borders.

Steps to Create a Border around an Image using OpenCV:

1. Setup:

Ensure you have OpenCV installed:

pip install opencv-python

Import necessary libraries:

import cv2
import numpy as np

2. Load the Image:

Load the image on which you want to add a border:

image = cv2.imread('path_to_image.jpg')

3. Add the Border:

Use the cv2.copyMakeBorder() function:

bordered_image = cv2.copyMakeBorder(image, top, bottom, left, right, borderType, value=color)

Where:

image: The source image.
top, bottom, left, right: Width of borders in the respective directions.
borderType: The type of border to be added (e.g., cv2.BORDER_CONSTANT for a colored border, cv2.BORDER_REPLICATE to replicate the edge-most content).
color: Color of the border (used only if borderType is cv2.BORDER_CONSTANT).

Example of adding a constant blue border of 10 pixels in all directions:

border_size = 10
color = [255, 0, 0]  # Blue color in BGR format
bordered_image = cv2.copyMakeBorder(image, border_size, border_size, border_size, border_size, cv2.BORDER_CONSTANT, value=color)

Example of adding a replicated border:

border_size = 10
bordered_image = cv2.copyMakeBorder(image, border_size, border_size, border_size, border_size, cv2.BORDER_REPLICATE)

4. Display the Image:

cv2.imshow('Bordered Image', bordered_image)
cv2.waitKey(0)
cv2.destroyAllWindows()

Upon running the code, you'll see your image displayed with the desired border. Depending on the parameters you choose, this can be a constant color or a replicated edge of the image.

This wraps up the tutorial on adding borders to images using OpenCV. The copyMakeBorder() function is versatile and can create various border styles by adjusting its parameters.

Adding Borders to Images in OpenCV:

Description: Introduction to basic image border addition in OpenCV.

Code:

import cv2
import numpy as np

# Read an image
img = cv2.imread('image.jpg')

# Add a border to the image
border_color = (0, 255, 0)  # Green color
border_thickness = 10
img_with_border = cv2.copyMakeBorder(img, border_thickness, border_thickness, border_thickness, border_thickness, cv2.BORDER_CONSTANT, value=border_color)

# Display the original and bordered images
cv2.imshow('Original Image', img)
cv2.imshow('Image with Border', img_with_border)
cv2.waitKey(0)
cv2.destroyAllWindows()