Using Wavefront Coding in presence of non-symmetric aberrations

Wavefront coding is a hybrid technology designed to increase depth of field of conventional optics but it can also be used to compensate for other aberration and ease tolerancing. The goal of our research is to apply this technology to panoramic imager. Panoramic imagers suffer from an increase level of aberration due to the large field of view and it is also subject to a special tolerance process. They also typically have a wide variation of the point spread function (PSF) across the field of view and suffer from non-symmetric aberration like coma and astigmatism. To obtain the best result using wavefront coding, the PSF should be as invariant as possible over the whole field of view. Asymmetric phase masks, when used in systems having non-negligible asymmetric aberrations, generate variations in the final image quality. For that reason, a model that predicts the final image quality of wavefront coded system is needed. The possibility of using two surfaces for wavefront coding has been studied. The final results were analysed using a variance based image quality criterion. From these results, it is possible to optimize phase mask for panoramic imager and predict the resulting image quality.