Focal Sweep Imaging with Multi-focal Diffractive Optics

Y. Peng, X. Dun, Q. Sun, F. Heide, W. Heidrich
ICCP, (2018)

Focal Sweep Imaging with Multi-focal Diffractive Optics


Depth-dependent defocus, Computational imaging


Depth-dependent defocus results in a limited depth-of-field in consumer-level cameras. Computational imaging provides alternative solutions to resolve all-in-focus images with the assistance of designed optics and algorithms. In this work, we extend the concept of focal sweep from re- fractive optics to diffractive optics, where we fuse multi- ple focal powers onto one single element. In contrast to state-of-the-art sweep models, ours can generate better- conditioned point spread function (PSF) distributions along the expected depth range with drastically shortened (40%) sweep distance. Further by encoding axially asymmetric PSFs subject to color channels, and then sharing sharp in- formation across channels, we preserve details as well as color fidelity. We prototype two diffractive imaging systems that work in the monochromatic and RGB color domain.Experimental results indicate that the depth-of-field can be significantly extended with fewer artifacts remaining after the deconvolution.




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