Methods and systems for the absolute high-resolution measurement of angle of rotation of a shaft, which allow for concurrent measuring of axial displacement and/or encoded identification information, are disclosed. Included is a method for measuring characteristics of a rotating shaft comprising obtaining optical signals by optically probing one or more patterns having a leading edge and a series of symbols disposed at one or more circumferences of the shaft; oversampling the optical signals; measuring time of arrival for the leading edges and determining therefrom an amount of time between arrival of two or more of the leading edges; interpolating and extrapolating the amount of time between arrival of the leading edges; and determining therefrom one or more of shaft twist, angle of rotation and/or axial loading, translation, or displacement. The methods include optically probing a pattern disposed around the circumference of a shaft that comprises a series of wedge-shaped symbols.