Evolution of the AWARE2 Gigapixel Camera
The AWARE2 camera has evolved since its conception in 2011
and first gigapixel images in
September 2011. Initial composites from the micro-cameras were
based off the ray trace model, which varied from the actual
camera. This caused overlap errors, uneven illumination,
unregistered overlapped regions, and pointing mismatches. Auto
focus, auto exposure, and live-view mode were unavailable, causing
many micro-cameras to under preform. In early images dynamic range was forfeited until HDR tonemapping was added to the compositer.
Overview of Advancements
The relative illumination map from the Zemax optical model varies significantly from
the actual illumination, due mainly from stray light, shown
below. The bright rings towards the edge of the field are
caused by reflections from the edges of the front doublet in the
micro-optic. To correct this, flat field images were taken and
used to divide through the image, vitually eliminating this problem.
Gaps in the Image Field
Gaps in the image field are caused by pointing errors from the
actual camera versus theoretical. A look-up table was used to
combine the images shown below, where large gaps in the field are
shown. Finding control points for registration corrects the
lookup table and eliminates most of the gaps.
The first few runs of micro-optics degraded in image quality rapidly
towards the edges. Tolerancing, diffractive optics errors,
and modeling problems caused significant blurring. Glass optics
have been designed and show excellent image quality. Improved plastic
optics are under development in order to keep the cost per
micro-camera as low as possible.
The glass micro-optics image is shown below, at 100% zoom level. The edge sharpness is nearly identical to center.
Registration errors, shown below, arise from pointing errors. Control
points were found in sets of images to build up a look-up table based on the actual
camera pointing, fixing this problem.