Wavelet transform based de-noising method for self mixing interferometry signals

Self-mixing interferometry (SMI) signals are observed from a laser diode (LD) with optical feedbacks induced by an external target. SMI signals carry information related to both of the target and parameters of the LDs. However, the noise contained in SMI signals greatly degrades the applications of the SMI systems. This paper proposes a wavelet transform based de-noising method which can effectively eliminate noise while keeping an SMI waveform less changed. The proposed method is verified by both simulations and experiments