An economical optical system design using phase diversity

Abstract

The resolution of an incoherent imaging system is olden limited aberrations. Phase aberrations by phase arise from a variety of sources including atmospheric turbulence, misaligned optical and improper mirror figure. Knowledge of phase aberrations affords their cohesion either by using adaptive optics or postdetection deblurring of the imagery. A well-known postdetection method called phase diversity (PD) is employed for this research. The joint estimation of an object and the aberrations of an incoherent imaging system from multiple images incorporating phase diversity is investigated. The technique requires the collection of two or more images. One of these images is the conventional focal-plane image that has been degraded by the unknown aberrations. Additional images of the same object are formed by translating the detector array along the optical axis with a known amount of defocus. This method was first introduced by Gonsalves. He derived an objective function (error matrix) for the estimation of aberration parameters. By employing combinatorial search approach, this error matrix was minimized and the aberration parameters were found out in terms of Zernike coefficients which is a well-known method for aberration parameterization. The most prominent result of this research is demonstrated by the fact that the PD method works for small aperture telescope in laboratory environment with the use of an excellent optical system installed specifically for the purpose.