Large Field-of-View Imaging With Thin-Plate Optics. We design a lens with compact form factor using one (or two) optimized refractive surfaces on a
thin substrate (left). This optimization results in a dual-mixture point spread function (center-left insets), which is nearly invariant to the incident angle,
exhibiting a high-intensity peak and a large, almost constant, tail. We show the sensor measurement (center) and image reconstruction (right) in natural
lighting conditions, which demonstrate that the proposed deep image recovery effectively removes aberrations and haze resulting from the proposed thin-plate
optics. Our prototype single element lens achieves a large field-of-view of 53◦ with a clear aperture of f /1.8 and effective aperture of f /5.4, see paper.
|
Typical camera optics consist of a system of individual elements that are
designed to compensate for the aberrations of a single lens. Recent computational
cameras shift some of this correction task from the optics to
post-capture processing, reducing the imaging optics to only a few optical
elements. However, these systems only achieve reasonable image quality
by limiting the field of view (FOV) to a few degrees -- effectively ignoring
severe off-axis aberrations with blur sizes of multiple hundred pixels.
In this paper, we propose a lens design and learned reconstruction architecture
that lift this limitation and provide an order of magnitude increase
in field of view using only a single thin-plate lens element. Specifically, we
design a lens to produce spatially shift-invariant point spread functions, over
the full FOV, that are tailored to the proposed reconstruction architecture.
We achieve this with a mixture PSF, consisting of a peak and and a low-pass
component, which provides residual contrast instead of a small spot size as
in traditional lens designs. To perform the reconstruction, we train a deep
network on captured data from a display lab setup, eliminating the need
for manual acquisition of training data in the field. We assess the proposed
method in simulation and experimentally with a prototype camera system.
We compare our system against existing single-element designs, including
an aspherical lens and a pinhole, and we compare against a complex multielement
lens, validating high-quality large field-of-view (i.e. 53-deg) imaging
performance using only a single thin-plate element.
|
