Performing in-line test, measurement and inspection in an automated, production environment requires a fast, accurate and robust system that can withstand the environmental challenges found on the factory floor. Optical measuring instruments are one way to measure in this environment because they are less vibration sensitive than contact-based alternatives. But optics have to see something to measure it--just as tactile needs to touch--which requires a part fixtured in a position that allows the measurement tool to "see" the part and make the optical probe.

One way to establish a line of sight is by making the optical system mobile. Some companies move optical probes on rails; one Israeli-based company puts them on wheels or mounts them on robots.