  Compressive imaging using coded apertures (CA) is a powerful technique that
can be used to recover depth, light fields, hyperspectral images and other
quantities from a single snapshot. The performance of compressive imaging
systems based on CAs mostly depends on two factors: the properties of the
mask's attenuation pattern, that we refer to as "codification" and the
computational techniques used to recover the quantity of interest from the
coded snapshot. In this work, we introduce the idea of using time-varying CAs
synchronized with spatially varying pixel shutters. We divide the exposure of a
sensor into sub-exposures at the beginning of which the CA mask changes and at
which the sensor's pixels are simultaneously and individually switched "on" or
"off". This is a practically appealing codification as it does not introduce
additional optical components other than the already present CA but uses a
change in the pixel shutter that can be easily realized electronically. We show
that our proposed time multiplexed coded aperture (TMCA) can be optimized
end-to-end and induces better coded snapshots enabling superior reconstructions
in two different applications: compressive light field imaging and
hyperspectral imaging. We demonstrate both in simulation and on real captures
(taken with prototypes we built) that this codification outperforms the
state-of-the-art compressive imaging systems by more than 4dB in those
applications.
