An algorithm for finding image clues stable under zoom and rotation.
SIFT is like sticking tiny name tags on the corners of a photo. Turn the photo or stand farther away, and the tags still say, “Yep, same spot.”
It is used for photo stitching and object matching. It is old-school Computer Vision muscle.
Computer Vision
SIFT was a classic tool for image matching in Computer Vision.
Feature-engineering
SIFT hand-builds comparable features from local texture.
RANSAC
After SIFT matches points, RANSAC often removes bad matches.
CNN
CNN later replaced many hand-built features with learned ones.