Motion capture is the process of recording the movement of objects or people. It is used in military, entertainment, sports, medical applications, and for validation of computer vision and robots. In filmmaking and video game development, it refers to recording actions of human actors and using that information to animate digital character models in 2D or 3D computer animation. When it includes face and fingers or captures subtle expressions, it is often referred to as performance capture. In many fields, motion capture is sometimes called motion tracking, but in filmmaking and games, motion tracking usually refers more to match moving.
Reflective markers attached to skin to identify body landmarks and the 3D motion of body segments
A dancer wearing a suit used in an optical motion capture system
Markers are placed at specific points on an actor's face during facial optical motion capture.
Body motion capture
In physics, motion is when an object changes its position with respect to a reference point in a given time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed, and frame of reference to an observer, measuring the change in position of the body relative to that frame with a change in time. The branch of physics describing the motion of objects without reference to their cause is called kinematics, while the branch studying forces and their effect on motion is called dynamics.
A car is moving in high speed during a championship, with respect to the ground the position is changing according to time hence the car is in relative motion
Image: Velocity vs time graph for average acceleration that shows dependence on time