This paper presents a general displacement reconstruction algorithm for sensors based on self-mixing (SM) interferometry suitable to work at different optical feedback conditions. The approach relies on a robust phase observation through analytic signals for the fringe detection stage, while the motion of the pointed target is retrieved by a self-adapting filter in a piece-wise basis. The implementation for real-time calculations demonstrates the feasibility of robust SM sensors for different usage conditions without the need of modifying the base device configuration.