Abstract:
Systems and methods are provided for projecting a virtual image of an object. A projector mounted on the object for projecting a light beam. A photographic plate is provided that includes an interference pattern imprinted onto at least one surface, wherein the interference pattern manipulates the light to form a hologram beam such that a detector detecting the hologram beam detects a virtual image of the object that has a light signature at a greater intensity than a light signature of the object.

Description:
TECHNICAL FIELD 
     The present invention relates generally to projection systems, and more particularly to systems and methods for projecting a virtual image of an object. 
     BACKGROUND OF THE INVENTION 
     Holography is a technique for recording and later reconstructing the amplitude and phase distribution of a coherent wave disturbance. Generally, the technique utilized for producing a holographic element is accomplished by imprinting a pattern of interference between two optical beams or waves. Holography was developed for displaying three-dimensional images. The beams, one reflected from an object, called the object beam and a second beam that bypasses the object is called the reference beam, are used to record the information in light sensitive recording medium, such as a holographic film or plate. 
     SUMMARY OF THE INVENTION 
     In accordance with an aspect of the present invention, a projector system is provided for projecting a virtual image of an object. A projector is mounted on the object for projecting a light beam. A photographic plate is provided that includes an interference pattern imprinted onto at least one surface, wherein the interference pattern manipulates the light beam to form a hologram beam such that a detector detecting the hologram beam detects a virtual image of the object that has a light signature at a greater intensity than a light signature of the object. 
     In accordance with another aspect of the present invention, a system is provided for providing a virtual image of an object to a detector. Means for providing a hologram beam from the object at a first location are included. Means for redirecting the hologram light beam toward the detector are also included. The hologram beam causes the detector to detect the virtual image of the object at a second location spaced apart from the first location, wherein the virtual image of the object has a light signature with a greater intensity than a light signature of the object. 
     In accordance with yet another aspect of the present invention, a method is provided for protecting an object. An incoming threat is detected at the object in a first location. At least a portion of a projection system of the object is aligned toward the threat. A hologram beam is projected toward the threat that causes the threat to detect a virtual image of the object a second location, the second location being spaced apart from the first location, wherein the virtual image of the object has a light signature with a greater intensity than a light signature of the object. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exemplary scenario that includes a projection system for projecting a virtual image of an object to a detector in accordance with an aspect of the invention. 
         FIG. 2  illustrates an exemplary system for imprinting an interference pattern onto a photographic plate in accordance with an aspect of the invention. 
         FIG. 3  illustrates another exemplary scenario for implementing a projection system in accordance with an aspect of the invention. 
         FIG. 4  illustrates yet another exemplary scenario for implementing a projection system in accordance with an aspect of the invention. 
         FIG. 5  illustrates an exemplary methodology for protecting a valuable asset in accordance with an aspect of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present system relates to a virtual image projection system that can be mounted on a valuable asset, such as an in-orbit satellite. The valuable asset can detect an incoming threat, such as a guided missile. The valuable asset can direct a projection system toward the incoming threat and project a hologram beam that causes the incoming threat to detect a virtual image of the valuable asset. Upon detection of the virtual image, the threat changes its trajectory toward the virtual image of the valuable asset, thereby missing the valuable asset. 
       FIG. 1  illustrates an example of a scenario  2  that includes a virtual image projection system  4  in accordance with an aspect of the invention. The virtual image projection system  4  includes a projector  6  that can project a light beam, which can be referred to as a reconstruction beam  8 , onto a photographic plate  10  at an angle of incidence (e.g., about 45 degrees) for the photographic plate  10 . The photographic plate  10  has an interference pattern of an object (e.g., a valuable asset such as a satellite) imprinted on at least one side of the photographic plate  10 . The virtual image projection system  4  can be configured such that when the projector  6  projects the reconstruction beam  8  onto the photographic plate  10  the photographic plate  10  manipulates the reconstruction beam  8  to create a hologram beam  12 . The hologram beam  12  can have a wavelength of about 8-10 micrometers (e.g., an infrared beam) or about 450 micrometers (e.g., an ultraviolet beam). Additionally, or alternatively, the hologram beam  12  could have multiple wavelengths, or the wavelength of the hologram beam  12  could be in a different wave band, such as the visible light wave band. The hologram beam  12  can be provided to a folding mirror  14 . The folding mirror  14  can be implemented, for example, as a mirror with an adjustable position relative to the photographic plate  10 . The folding mirror  14  could be controlled, for example, with an electric motor (not shown). 
     The virtual image projection system  4  can be designed such that the folding mirror  14  reflects the hologram beam  12  toward a detector  16 . The detector  16  could be mounted, for example, on a threat to the valuable asset. The threat could be implemented as a self-guided projectile, such as a guided missile, smart bomb, smart munitions, etc. The detector  16  could be implemented, for example, as an ultraviolet (UV) or infrared (IR) detector. One skilled in the art will appreciate, however, that the detector  16  could be configured to include other wavebands as well. When the reflected hologram beam  18  is provided to the detector  16 , the detector  16  perceives a virtual image  20  of the object in a direction generally opposite to a trajectory of the reflected hologram beam  18 , which direction is indicated by the arrow at  22 . The virtual image  20  can be at about one coherence length away from the object, such as about 1 kilometer. 
       FIG. 2  illustrates an example of a system  50  for storing a virtual image in accordance with an aspect of the invention. The system  50  includes a projector  52  that can project light beams  54  onto a beam splitter  56 . The beam splitter  56  could be implemented, for example, as a half-silvered mirror, a plate of glass with a pellicle film, a configuration of prisms, etc. The beam splitter  56  could be configured such that light beams  54  incident at about 45 degrees to the beam splitter  56  can be split such that about one half of the light beams  54  are transmitted as transmitted beams  58  and about one half are reflected as reflected beams  60 . 
     The transmitted beams  58  can be directed to an object  62 . The object  62  can be, for example, a valuable asset (e.g., a satellite, an aircraft, a mobile vehicle, etc.) or a model of a valuable asset. Some portion of the transmitted beams  58  can be reflected by the object  62  (referred to as an object beam  64 ) onto a photographic plate  66 . The photographic plate  66  could be implemented, for example, as a metal plate coated with photographic film. Alternatively, the photographic plate  66  can be implemented as an emulsion of salt applied to a glass plate. One skilled in the art will appreciate the various structures that could be used to implement the photographic plate  66 . Additionally, the reflected beams  60  can be provided to a mirror  68  that can reflect the reflected beams  60  (referred to as a reference beam  70 ) onto the photographic plate  66 . 
     The reference beam  70  and the object beam  64  are coherent since both the reference beam  70  and the object beam  64  originated from the light beams  54  provided by the projector  52 . Due to the coherency of the object beam  64  and the reference beam  70 , optical interference between the reference beam  70  and the object beam  64  produces a series of intensity fringes that can be imprinted on the photographic plate  66 . These fringes imprint a type of diffraction grating on the film, which can be referred to as an interference pattern  72 . When the photographic plate  66  is later illuminated by a substitute reference beam (not shown), the object beam  64  is reconstructed, producing a three dimensional virtual image of the object  62 . 
       FIG. 3  illustrates another exemplary scenario  100  of a target  102  and a threat  104  in accordance with an aspect of the invention. The target  102  could be, for example, a valuable asset, such as an in-orbit satellite, an aircraft, a vehicle, etc. The threat  104  could be, for example, a guided missile, a smart bomb, guided munitions, etc. The target  102  can include, for example, a threat detector  106 . The threat detector  106  could be implemented, for example, as an IR or UV detector that can detect the presence of an incoming threat, such as the threat  104 . For instance, the threat detector  106  can detect a plume of the threat  104 . In such a situation, the threat detector  106  can determine location information for the threat  104 . Alternatively, the threat detector  106  could be implemented as software and/or hardware that processes a signal from a ground station that warns the target  102  of the threat  104 . The incoming signal can include, for example, location information of the threat  104 . The location information can be implemented, for example, as coordinates (e.g., longitude, latitude and altitude) of the threat  104 . 
     When the threat  104  is detected, the threat detector  106  can provide the location information to a controller  108  that enables the controller  108  to determine a trajectory of the threat  104 . The location information can be provided continuously or intermittently. The controller  108  can employ the location information to control a projection system  110  mounted on the target  102 . The projection system  110  could be implemented, for example as the projection system  4  illustrated in  FIG. 1 . The controller  108  can activate a projector of the projection system  110 , and move a folding mirror of the projection system  110  and/or a turret to which the projection system  110  is mounted to direct a hologram beam  112  toward the threat  104 . 
     The threat  104  can include, for example a tracking system  114 . The tracking system  114  can include, for example, a UV or IR detector to guide the threat  104  toward the target  102 . However, when the threat  104  receives the hologram beam  112  from the projection system  110  of the target  102 , the threat  104  perceives a virtual image of the target  102 . The hologram beam  112  can be provided with an intensity such that the virtual image of the target  102  has a greater intensity light signature than a light signature of the target  102  such that the virtual image of the target  102  can be perceived as brighter (in the IR and/or UV spectrum) than the target  102  by the threat  104 . Accordingly, the threat  104  will be diverted toward a perceived location of the virtual image, which can be about 1 kilometer away from the target  102 . Thus, the threat  104  will miss the target  102  entirely, such that the target  102  remains undamaged. 
       FIG. 4  illustrates yet another exemplary scenario  150  that includes an in-orbit satellite  152  (e.g., a target and/or valuable asset) and an incoming guided missile  154  (e.g., a threat) that employs a projection system (such as the virtual image projection system  4  illustrated in  FIG. 1 ) in accordance with an aspect of the invention. In the present exemplary scenario  150 , the incoming guided missile  154  travels in a trajectory toward the satellite  152  indicated by an arrow at  156 . The satellite  152  is configured to detect the incoming guided missile  154 , for example, with a threat detector as discussed with respect to  FIG. 3 . Once detected, the satellite  152  is configured to project a hologram beam  158  toward the incoming guided missile  154 . In response to receiving the hologram beam  158 , the incoming guided missile  154  perceives a virtual image of the satellite  160  spaced apart from the satellite  152  by about 1 kilometer. 
     The hologram beam  158  can be provided at an intensity such that a light signature of the virtual image of the satellite  152  will have a greater intensity in the UV and/or IR spectrum than the satellite  152  itself, such that the incoming guided missile  154  will perceive the virtual image of the satellite  160  to be the location of the satellite  152 . Accordingly, the incoming guided missile  154  will be diverted toward the virtual image of the satellite  160 , indicated by an arrow at  162 . Once diverted, the incoming guided missile  154  will miss the satellite  152 , such that satellite  152  is undamaged by the incoming guided missile  154 . 
     In view of the foregoing structural and functional features described above, methodologies will be better appreciated with reference to  FIG. 5 . It is to be understood and appreciated that the illustrated actions, in other embodiments, may occur in different orders and/or concurrently with other actions. Moreover, not all illustrated features may be required to implement a method. 
       FIG. 5  illustrates a methodology for protecting a valuable asset (e.g., an in-orbit satellite, an aircraft, a vehicle, etc.) in accordance with an aspect of the invention. At  200 , an incoming threat (e.g., a guided missile, a smart bomb, guided munitions, etc.) is detected at the valuable asset. The threat could be detected, for example, with a threat detector of the valuable asset. The threat detector can provide, for example, location information that can identify a location and/or a trajectory of the incoming threat to a controller of the valuable asset. 
     At  210 , the controller of the valuable asset analyzes the location information to calculate the location and/or trajectory of the incoming threat. At  220 , the controller aligns an image projection system toward the incoming threat. The aligning can include, for example, aligning a turret to which the projection system is mounted and/or aligning a folding mirror of the projection system. At  230 , the controller causes the projection system to project a hologram beam toward the threat. The hologram beam causes the threat to detect a virtual image of the valuable asset. The hologram image can be provided with an intensity that causes a light signature of the valuable asset to be greater than an intensity of a light signature of the valuable asset. Upon detection of the virtual image, the trajectory of the threat is altered toward the perceived location of the virtual image, thereby causing the threat to miss the valuable asset. 
     What has been described above includes exemplary implementations of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to embrace all such alterations, modifications and variations that fall within the scope of the appended claims.