title: Determination of linear displacement by envelope detection with maximum likelihood estimation.
abstract: We demonstrate in this report an envelope detection technique with maximum likelihood estimation in a least square sense for determining displacement. This technique is achieved by sampling the amplitudes of quadrature signals resulted from a heterodyne interferometer so that the resolution of displacement measurement of the order of λ/10(4) is experimentally verified. A phase unwrapping procedure is also described and experimentally demonstrated and indicates that the unambiguity range of displacement can be measured beyond a single wavelength.
authors.affiliation: Department of Computer and Communication Engineering, Nan-Kai University of Technology, 542, Taiwan.
authors.forename: Kuo-Chen
authors.initials: KC
authors.lastname: Lang
authors.forename: Hui-Kang
authors.initials: HK
authors.lastname: Teng