Image plane interference co-phasing technology for synthetic digital holography

Abstract

Synthetic aperture is a high-resolution imaging technique which can extend the resolution Rayleigh limit capability of an aperture, while digital holography is a useful digital imaging tool. When synthetic aperture meets digital holography, a high-resolution image can be digitally achieved without many complex optic path adjust systems. However, because of the position errors and phase errors, the synthesis is always difficult to realize. In this paper, we analyzed the sources and influences of these errors which mainly include the phase errors and the shape and position errors, then proposed a valid image plane interference based digitally co-phasing method. A combination of the SPGD (stochastic parallel gradient descent) algorithm with the KAZE-based registration algorithm was proposed to respectively correct the de-phased errors and the shape and position errors. Experiment demonstrated that a high-resolution synthesized image can be achieved with this method without any adjust of the optical path. The biggest advantage of the proposed method is that it can be applied in short and long distance situations, or one sensor is far away from another, or the sensor is large sized, or the angle among sensors is relatively big.