Enhanced Lenses
During past several decades, L-3 Brashear manufactured
and delivered more than 150 range lenses with focal lengths
of 50, 100, and 150 inches (SR-50, SR-100, and SR-150 respectively).
They have been widely used for training, testing, research,
target detection and tracking at many test ranges and launch
pads. We continue working on improving these products and
plan to offer “Enhanced Lens Options” including:
1. Hyper Focal Lens (HFL)
The HFL increases the depth of field and resolution. It
has been shown that non-Gaussian light beams have a good
potential for longer focal depth and higher resolution
imaging, particularly in limited visibility conditions.
The depth of field of view, for example, can be increased
5 to 10 times and image “dancing” in turbulent
atmospheric conditions reduced significantly. The latter
improves image spatial resolution. All Brashear range lenses
will be enhanced by adding a special snap-on waveplate,
providing conversion to non-Gaussian light beams in order
to increase the depth of field and spatial resolution.
Currently, the waveplate for SR-50 is in production and
will be tested in the lab and in the field during this
year. The next step will be development of the waveplates
for all models of our standard range lenses. High field
depth is exceptionally important for tracking fast moving
targets.
2. Broad Band Lens
The Broad Band Lens expands the spectral range to SWIR.
Some of our range lenses have low aberrations, combined
with acceptable performance of AR coating in a broad spectral
range 0.4 – 3 microns. It would be beneficial for
detecting/tracking targets to extend the work spectral
band beyond the range of sensitivity of silicon detectors.
The experiments are currently under way to couple an SR-100
lens with a SWIR one-megapixel video camera. Also, two
cameras may be coupled to the same lens to cover a broad
spectral band 0.4 – 3 microns in each acquired frame.
Resulting images can be used separately or fused into a
synthetic broadband image to increase the amount of detected
details as well the detection range.
For further information, please contact
L-3 Brashear
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