Transparent graphics art: Adding a background layer | by Florian Trautweiler | January, 2025
How to process images with Alpha channel using OpenCV + Python
Recently, I needed to add a white background to a few photos with transparent backgrounds. Naturally, I used it Python with OpenCV to automate the process, I wouldn't open a photo editor for each of these photos. In my first attempt to use this, I didn't succeed and had to redo, so I thought I'd share the process with you.
If you want to follow along, be sure to enter the opencv-python again numpy package in your local Python environment. You can use the following transparent image of the figure to check it, you can download it from here.
Upload an image via the Alpha channel
In the first step, we need to load a transparent image including the alpha channel. When we upload an image normally with cv2.imread without the required parameter, it will simply ignore the alpha channel and the image will be completely black this time.
img = cv2.imread("equation.png")cv2.imshow("Image", img)
cv2.waitKey(0)
cv2.destroyAllWindows()
