Normalization-free displacement reconstruction method based on fringe scaling

The knotty problems in the displacement reconstruction based on the self-mixing (SM) technique are the estimation of the self-mixing interferometry parameters and the normalization of SM signals (SMSs) since they are all very time-consuming and based on complex algorithms. This has an unfavorable effect on the real-time and low-cost natures of the SM displacement sensor. In the paper, we have presented a simple method of displacement retrieval with a high resolution, which does not require the parameter estimation and normalization. The proposed method is based on the scaling of individual fringes in SMSs and speckle noise proof. The simplicity of the method will make a great contribution to lowering the cost of the SM displacement sensor and improving the reliability and resolution of the sensor.