How to create a black image and a white image using OpenCV Python?

OpenCV is an open-source computer vision and machine learning software library that is used for various image processing operations. It is widely used for creating image filters, transforming images, and detecting objects in images. In this tutorial, we’ll learn how to create a black image and a white image using OpenCV Python.

Creating a black image using OpenCV Python

To create a black image using OpenCV Python, we first need to import the OpenCV library. Once we have imported the library, we can create a black image with the help of the cv2.imread function.

import cv2

# Create a black image with the help of cv2.imread function
black_image = cv2.imread('black_image.jpg')

In the above code snippet, we have used the cv2.imread function to create a black image. The function takes the image file name as an argument and returns an array of pixel values. We have assigned this array to the variable ‘black_image’.

We can also create a black image of a specific size using the numpy.zeros function. The numpy.zeros function takes the shape of the image as an argument and returns an array of zeros of the specified shape.

import numpy as np

# Create a black image of size 400x400
black_image = np.zeros((400, 400))

In the above code snippet, we have used the numpy.zeros function to create a black image of size 400×400. We have assigned the array returned by the function to the variable ‘black_image’.

Creating a white image using OpenCV Python

To create a white image using OpenCV Python, we can make use of the numpy.ones function. The numpy.ones function takes the shape of the image as an argument and returns an array of ones of the specified shape.

import numpy as np

# Create a white image of size 400x400
white_image = np.ones((400, 400))

In the above code snippet, we have used the numpy.ones function to create a white image of size 400×400. We have assigned the array returned by the function to the variable ‘white_image’.

We can also create a white image using the cv2.imread function if we have a white image file available.

import cv2

# Create a white image with the help of cv2.imread function
white_image = cv2.imread('white_image.jpg')

In the above code snippet, we have used the cv2.imread function to create a white image. The function takes the image file name as an argument and returns an array of pixel values. We have assigned this array to the variable ‘white_image’.

Conclusion

In this tutorial, we learned how to create a black image and a white image using OpenCV Python. We explored different ways of creating these images, including using the cv2.imread and numpy.zeros or numpy.ones functions. With these techniques, you can easily create images of different sizes and colors to suit your specific image processing needs.