A cropped face is not yet comparable to another cropped face. The same person photographed from a different angle, distance, or head tilt produces a very different crop. Landmark alignment fixes this: the system locates key points such as the eye centers, nose tip, and mouth corners, then rotates, scales, and shifts the image so those points land in a standard position. After alignment, the same person photographed at different angles lands in the same normalized frame, which is what makes later comparison meaningful.
How AI Recognizes a Face: From Detection to Identity Match