Image Annotation

In a typical computer vision task, we process images in a chained manner: an original image gets transformed into another image, which is processed into another image by a second step, and so on. We might want to annotate our intermediary images to help us understand the effect of each processing step.

The OpenCV library offers various drawing functions that we can use to annotate our images. Let’s examine a few of them.

Direct pixel value access

The most basic way to modify an image is to access its values directly, just like any NumPy array.