know about laser measuring system

Hi friends,
Unique feature of laser measuring system is that they use a coherent beam of light that can be projected with minimum diffusion. High energy laser is used for welding and cutting where as lower energy laser beams are used for inspection. A photo detector on the far side of the object scenes the light beams except during the sweep period when it is interrupted by part. This period is timed with great accuracy and correlated with the part size. This system requires very short cycle time and hence can be used for high production online inspection. A microprocessors based system is used to convert time signal to linear displacement and signals other equipment for necessary correction if any. Application: roll mill operation, wire extrusion, grinding processes. Thank you.