This paper presents a robust phase estimation to detect fringes of self-mixing signals for all feedback levels. It aims to avoid the need of restricting a particular working feedback regime for a sensor which is usually done by external optical/mechanical components. By removing the local offset from a set of fringes, their orthogonal representation can be obtained through the Hilbert transform allowing a unique calculation disregarding their shape in time. From it, it is possible to retrieve the displacement of a pointed target from a wide variety of usage conditions. The pertinence of the proposed approach for sensor implementation is also demonstrated.