Performance limits of binary annular phase masks codesigned for depth-of-field extension

Rafael Falcón (1) , François Goudail (1) , Caroline Kulcsár (1) , Hervé Sauer (1)

1 Laboratoire Charles Fabry / Spim

We investigate the performance limits of hybrid imaging systems including annular binary phase masks optimized for depth-of-field (DoF) extension, as a function of the number of rings and the desired DoF range. The mask parameters are optimized taking into account deconvolution of the acquired raw image in the expression of the global performance of the imaging system. We prove that masks with a limited number of rings are sufficient to obtain near-optimal performance. Moreover, the best achievable image quality decreases as the required DoF range increases, so that for a given required image quality, the DoF extension reachable with binary phase masks is bounded. Finally, these conclusions are shown to be robust against different optical system aberrations and models of scene power spectral density. These results are important in practice to decide if annular binary phase masks are the relevant solution for a given imaging problem and for mask manufacturing, since the number and thickness of the rings reachable at affordable cost by technology are generally limited.

Mots clés: encoding; optical system codesign; phase-only filters; phase-only filters; wavefront encoding; image processing; binary phase masks; optical system co-design; wavefront; binary phase masks

Domaines: Optique / photonique; Traitement du signal et de l'image [eess.SP]

Rafael Falcón, François Goudail, Caroline Kulcsár, Hervé Sauer. Performance limits of binary annular phase masks codesigned for depth-of-field extension. Optical Engineering, 2017, 56 (6), pp.065104. ⟨10.1117/1.OE.56.6.065104⟩. ⟨hal-01682896⟩