High speed measurement for object profiling using FMCW optical sensing system

Abstract

A sensor that is beneficial to inspect small devices has been missing in life science as well as industry. Frequency modulated continuous wave (FMCW) optical sensing system has been successful in profiling the image of a coin and a printed circuit board with the measurement accuracy of 3σ = 29 μm in 10 minutes by using a DFB laser. Here we propose and demonstrate a faster profiling system using a VCSEL. We applied three conditions for high-speed FMCW optical sensing system, i.e. symmetric method with the different modulation frequency, modulation amplitude, and asymmetric method. The results show that asymmetric method is successful in profiling a coin object with a diameter of 2.25 cm in 23.13 seconds.