PHASE NOISE IN STRUCTURED ILLUMINATION SYSTEMS

摘要

In contrast to interferometry, structured illumination measurement systems rely on the use of incoherent light. Therefore they are robust against most of the systematic effects that influence the phase measurement error in interferometry, like vibrations and phase shifting errors and thus are dominated by stochastic effects. The majority of prior research work concerning phase noise has been done in the field of interferometry. The results are most often based on the assumption of signal independent Gaussian noise and predict a phase noise that depends linearly on the visibility (i.e. the relative fringe contrast) and a signal to noise ratio that scales linearly with the unmodulated intensity. As modern cameras are typically limited by signal-dependent photon-noise, strong deviations from this theory can be observed for high irradiations. In this paper an approach that is based on the camera model of the standard EMVA 1288 is presented that takes this into account. This results in a phase evaluation with a precision approximately proportional to the square root of the unmodulated intensity. The findings are validated by means of simulations and experiments.