Patent Publication Number: US-2011050905-A1

Title: Target-Conforming Illuminator System

Description:
GOVERNMENT INTEREST 
     The invention described herein may be manufactured, used, sold, imported, and/or licensed by or for the Government of the United States of America. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to illumination devices for illuminating and identifying objects in darkness. 
     BACKGROUND OF THE INVENTION 
     Prior art illuminators generally illuminate a fixed field of view that does not distinguish background and foreground scene clutter from military targets of interest such as people, vehicles, or animals. In cases of extreme clutter, the illumination may not improve object visibility at all, while providing ease of navigation and targeting for enemy personnel, vehicles and weapons. 
     SUMMARY OF THE INVENTION 
     Accordingly, one object of the present invention is to provide illumination which conforms to the outline of specific warm objects of interest and does not illuminate cooler or non-moving background and foreground clutter, not of interest. 
     Another object of the invention is to enable many persons, such as, for example, the members of a rescue search party, to share the benefits of a thermal imager even though they are far removed from any imager display. 
     Yet another object of the invention is to illuminate unfriendly personnel, vehicular or other targets, while minimizing the enemy exploitability normally associated with conventional illuminators such as searchlights or flares. 
     These and other objects of the invention are achieved in one aspect by an illuminator. The illuminator comprises a thermal imager for generating a thermal image of a warm object, and means for converting the thermal image to a visible light image and projecting and superimposing the visible light image back onto the object to illuminate the object with light that conforms to the outline of the object so that the object is easier to see in darkness. 
     Another aspect of the invention involves an illuminating method comprising the steps of generating a thermal image of a warm object, converting the thermal image to a visible light image, and projecting and superimposing the visible light image back onto the object to illuminate the object with light that conforms to the outline of the object so that the object is easier to see in darkness. 
     Potential applications include improved battle space and a physical security illumination system that are less susceptible to enemy countermeasures. Other applications include improved air and ground-based search and rescue illumination, the reduction of light pollution, and possible less-blinding automobile headlights. 
    
    
     
       Additional advantages and features will become apparent as the subject invention becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows the invention as embodied in a typical search and rescue aircraft. 
         FIG. 2  shows another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows the invention as embodied in a typical airborne search and rescue aircraft  11 . The aircraft  11  includes a fuselage  13  having a cargo compartment  15 . According to the invention, an illuminator  17  is placed in the open door of the cargo compartment  15  for illuminating and identifying warm objects  19  on the ground, such as a moving person or a moving vehicle, in the darkness. 
     The illuminator  17  includes a thermal imager  21 , such as the Infrared Solutions model P200 LWIR 9-14u imager, and a visible light projection means  23  connected to the thermal imager. A thermal imager is a camera that takes pictures using the infrared portion of the electromagnetic spectrum. It is also known as a forward looking infrared (FLIR) system. While the visible light projection means  23  may take a variety of forms, conveniently it may take the form of a computer projector, such as the Epson company model EMP-61 projector, or a projection television, also the Epson company model EMP-61 (which accepts both television video as well as computer video inputs), collocated with the thermal imager  21  and oriented/equipped with compatible imager objective/projector optics, so that its field of view exactly matches that of the thermal imager. 
     In operation, an aircraft  11  on a search and rescue mission, circles a search area in the darkness and directs the thermal imager  21  at the ground. The thermal imager  21  generates thermal images of warm objects  19  of interest, and feeds them to the computer projector or projection television  23 . The computer projector or projection television  23  converts the thermal images to visible light images, and projects and superimposes them onto the objects  19 . The visible light images conform to the outlines of the objects  19  making them easier to see, while the cooler or non-moving background and foreground clutter remain dark. 
       FIG. 2 , wherein like reference numerals designate like or corresponding parts, shows another embodiment of the illuminator  17  which differs from the embodiment of  FIG. 1  in that a means  27  is inserted to connect between the thermal imager  21  and the computer projector or projection television  23  for the purpose of conformal illumination of only moving objects. While a variety of such means may be used, conveniently it may take the form of a video motion detector, such as the Colorado Video company model 442, or a video scene subtractor, such as the Colorado Video company model 442 (in video scene subtraction mode). 
     It is obvious that many modifications and variations of the present invention are possible in light of the above teachings. For example, the illuminator could be placed in a trainable turret of an aircraft or helicopter. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as described.