Measurement of Positions, Distances, and Displacement

Sensing of light beam length (L, distance) and position (x,y) has a lot of applications. Derivation of the continuous distance value gives the speed of an object. Continuous distance measurement determines also the displacement towards the observer (ΔL). Beam position measurement can be used to measure vertical (Δy) or horizontal (Δx) displacement and angle of the beam (a) or angular displacement (Δκ) as given in Fig. 5.1.

Lasers and light emitting diodes (LED) as a light source can effectively be used to measure distance, displacement, or position of an object. In particular, noncontacting distance measurements to a noncooperative target are of great interests for many industrial, sport, and traffic control applications.