  Retrieving the reflectance spectrum from objects is an essential task for
many classification and detection problems, since many materials and processes
have a unique spectral behaviour. In many cases, it is highly desirable to
capture hyperspectral images due to the high spectral flexibility. Often, it is
even necessary to capture hyperspectral videos or at least to be able to record
a hyperspectral image at once, also called snapshot hyperspectral imaging, to
avoid spectral smearing. For this task, a high-resolution snapshot
hyperspectral camera array using a hexagonal shape is introduced.The hexagonal
array for hyperspectral imaging uses off-the-shelf hardware, which enables high
flexibility regarding employed cameras, lenses and filters. Hence, the spectral
range can be easily varied by mounting a different set of filters. Moreover,
the concept of using off-the-shelf hardware enables low prices in comparison to
other approaches with highly specialized hardware. Since classical industrial
cameras are used in this hyperspectral camera array, the spatial and temporal
resolution is very high, while recording 37 hyperspectral channels in the range
from 400 nm to 760 nm in 10 nm steps. A registration process is required for
near-field imaging, which maps the peripheral camera views to the center view.
It is shown that this combination using a hyperspectral camera array and the
corresponding image registration pipeline is superior in comparison to other
popular snapshot approaches. For this evaluation, a synthetic hyperspectral
database is rendered. On the synthetic data, the novel approach outperforms its
best competitor by more than 3 dB in reconstruction quality. This synthetic
data is also used to show the superiority of the hexagonal shape in comparison
to an orthogonal-spaced one. Moreover, a real-world high resolution
hyperspectral video database is provided.
