Adaptive Camouflage
Source: Nasatech NASA's Jet Propulsion Laboratory, Pasadena, California
Lightweight optoelectronic systems built around advanced
image sensors and display panels have been proposed for making
selected objects appear nearly transparent and thus effectively
invisible. These systems are denoted "adaptive camouflage" because
unlike traditional camouflage, they would generate displays that would
change in response to changing scenes and lighting conditions.
The basic overall function of an adaptive camouflage
system would be to project, on the near side of an object, the scene
from the far side of the object. Although adaptive camouflage was
conceived for use in battlefield settings (see figure), there are also
potential commercial uses - for example, as an electronic "window"
that would display a
nearby outdoor scene in an office that lacks a real window, or as a
home security system in place of a door peephole.
A typical adaptive camouflage system would likely
include a network of flexible electronic flat-panel display units
arrayed in the form of a blanket that would cover all observable
surfaces of an object that one seeks to cloak. Each display panel
would contain an active-pixel sensor (APS) [or possibly another
advanced image sensor] that would look outward from the panel through
an aperture that would occupy only a small fraction of the area of the
panel. The blanket would also
contain a wiring harness that would include a cross-connected
fiber-optic network, through which the image from each APS would be
transferred to a complementary display panel on the opposite side of
the cloaked object.
The positions and orientations of all the image sensors
would be slaved to the position and orientation of one image sensor
that would be designated a master imager. The orientations would be
determined by a levelling instrument sensed by the master imager. A
central controller connected to an external light meter would
automatically adjust the brightness levels of all the display panels
to make them
conform to the to ambient lighting conditions. The underside of the
cloaked object would be illuminated artificially so that the display
from the top of the cloaked object would show the ground as though in
ambient light; if this were not done, then an obvious shadow-induced
discontinuity would be seen by an observer looking down from above.
The display panels could be sized and configured so that
a common inventory of such panels could be used to cloak a variety of
objects, without need to modify the objects. Sizes and weights of
representative adaptive camouflage systems and subsystems have been
estimated: The volume of a typical image sensor would be less than
about 1 in.3 ( 16 cm3). A system to completely cloak an object 10 m
long by 3 m high by 5 m wide would weigh less than about 100 lb ( 45
kg). If the object to be cloaked were a vehicle, then the adaptive
camouflage system could readily be operated on power provided by the
vehicle electrical system, without adversely affecting the operation
of the vehicle.
The Scene From Behind an Object would be displayed on
panels on the front of the object. The effect of cloaking is
illustrated in this simulated image of an armored vehicle with
adaptive camouflage on one side only.
This work was done by Philip Moynihan of Caltech and
Maurice Langevin of Tracer Round Associates, Ltd., for NASA's Jet
Propulsion Laboratory. For further information, access the Technical
Support Package (TSP) free on-line at www.nasatech.com under the
Electronic Components and Systems category.
NPO-20706
http://www.nasatech.com/Briefs/Aug00/NPO20706.html