Estimation of global visibility for low-quality fringe pattern using Fourier-polar transform

Abstract

When the interferometers with adjustable fringe visibility is used for high precision wavefront measurement, it needs to estimate the visibility of experimental patterns so as to obtain the interference patterns with the highest visibility. A new method combining Fourier-polar transform with directional projection is developed to estimate the global visibility of carrier fringe pattern. This method can also be applied to low-quality fringe patterns such as low contrast and low signal-to-noise ratio (SNR) that often appear in the interferometer testing. Theoretical analysis shows that this method is obviously superior to the direct calculation method. In addition, an illustrative experiment based on the radial shearing interferometer is given. Results generated from this method are compared with the derived values from theoretical model of experimental system, and exemplary agreement between both is demonstrated.