13.1 Image Processing

Image processing is the set of operations that turn a raw image into a cleaner, more useful version: resizing, adjusting brightness and contrast, removing noise, detecting edges, and converting between colour spaces. A digital image is just a grid of pixels, each with numbers for red, green and blue, so these operations are really mathematics applied to a matrix of values.

Imagine a photo of a national ID taken with a phone in a dim kebele office: it may be tilted, blurry and yellowish. Before any system can read it, image processing straightens it, brightens it, sharpens the text and removes the colour cast so the next stage has a clean image to work with.