A technique for estimating pixel motion between nearby video frames.
Optical flow is like a sports replay covered in tiny arrows. Even the hot dog wrapper gets a direction sign.
It shows how the picture moves from one frame to the next. Cars and robot cameras use it to track what moves.
Computer Vision
Optical flow gives Computer Vision a basic clue for motion in video.
SLAM
SLAM can use optical flow to track image changes and estimate pose.
Driving AI
Driving AI uses optical flow to judge how cars and people move.