 Laser surface velocimeters measure speed and length of moving surfaces on coils, strips, tubes, fiber, film, paper, foil, composite lumber, or almost any other moving material, including hot steel.LSVs can accomplish various tasks like cut-to-length control, part length and spool length measurement, speed measurement and speed control, differential speed measurement for mass flow control, encoder calibration, ink-jet marker control, and many others.Operating Principle of Laser Surface Velocimetry (Video)