Velocity measurement based on multiple self-mixing interference

This study proposes a novel algorithm based on the multiple self-mixing interference (MSMI) theory to measure the velocity of a remote target without contact. The principle of MSMI is presented and the corresponding formulas for velocity measurement are derived. Fast Fourier transform is applied to detect signal frequency and calculate velocity values. A low-cost, compact, and easy-to-operate experimental setup is also constructed. Experiments are conducted to validate the correctness of our algorithm. This algorithm can improve resolution more easily than conventional self-mixing interference methods.