Stereoscopy and refocusing from axial scanning in 3D imaging

Abstract

In the present work we use a monocular camera along with an electrically tunable lens (ETL) to acquire a multi-focus stack without mechanical displacements, avoiding vibrations and misregistration during imaging acquisition. It is possible to decode and reconstruct new images of interest (images that are not part of the original acquired stack) by digital processing algorithms with a physical basis. We show how Fourier domain operations along with the knowledge of the focal distances employed for sweeping the optical axis, enable the redistribution of the information encoded in the original stack. In this way, from the multi-focus stack, it is possible to refocus digitally the scene, with synthetically reshaped apertures (changing its shape and size), obtaining extended-depth-of-field as a particular case (i.e., as captured with a pin-hole camera). We can also consider displacements of the pinhole for shifting the viewer's perspective of the 3D scene and obtaining stereoscopic pairs of images (left and right eyes images) as particular cases. Finally, it is also possible to combine both implementations and reconstruct the scene as captured from a different perspective and with a different aperture at the same time.

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