Abstract:
Disclosed is a Discriminating Radial Illuminator (DRI), which is a portable illumination and obscuration system offering unique advantages over conventional methods of illumination. Exemplary uses include: Tactical illumination and obscuration for military, law enforcement and private security; special effects lighting for the entertainment industry; architectural and commercial lighting, both interior and exterior.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to lighting systems that are deployed in high threat environments, such as active combat zones, enhanced security areas, and situations requiring surveillance or crowd control. Relative lighting systems are also used, as general and specific lighting for theatrical and concert productions, sporting events, trade shows, and can be adjunct, to entertainments such as dancing. Commercial and architectural lighting systems utilized for signs and structures also relate to the present invention. 
         [0002]    Lighting can be an important factor in the management of high threat areas. Arrays of floodlights are used not only to illuminate an object, structure, or perimeter, but can be positioned specifically to blind and disorientate hostile personnel and optical equipment. Military, law enforcement, and security forces are trained to use such lights for both purposes. Likewise, spotlights, exploited for their focus, range and intensity to track and identify targets, can also be used, to blind and disorientate. Nearly ubiquitous in these applications, spotlights are often mounted on vehicles and buildings, but man-portable models of extraordinary power are available to tactical personnel. These various methods of illumination and lighting sightlines are considered in the design and operation of prisons, checkpoints, and other secure facilities. Many non-lethal weapon and deterrence systems also utilize the effects of visible light to temporarily disable personnel and optical equipment. 
         [0003]    The entertainment industry relies upon a plethora of specialized lighting fixtures and systems, not only for the primary illumination of a stage, field, or arena, but also as special effects. These components are often designed to be portable, rather than part of a permanent installation. Incandescent par cans, spotlights, strobes, lasers, and intelligent moving lights are a few of the types of fixtures commonly used. Complexity, precision, and the exact duplication of a performance are made possible by wired and wireless computerized control. These systems are commonly used to visually enhance trade shows, sporting events, and dance floors. 
         [0004]    Architectural and commercial lighting uses some fixtures and control systems similar to those found in entertainment lighting, one general design difference being the emphasis on long-term reliability and weatherproofing, rather than portability. These systems offer central control of interior and exterior lighting, and can be programmed to execute various lighting scenes on a schedule. 
       SUMMARY OF THE INVENTION 
       [0005]    Disclosed is a Discriminating Radial Illuminator (DRI), which is a portable illumination and obscuration system offering unique advantages over conventional methods of illumination. Exemplary uses include: Tactical illumination and obscuration for military, law enforcement and private security; special effects lighting for the entertainment industry; architectural and commercial lighting, both interior and exterior. 
         [0006]    A DRI comprises one or more light sources focused upon a mechanically rotated reflector, which directs the light output onto a horizontal plane. A high frequency of reflector rotation thus combines the focus and range of a tightly collimated spotlight beam with the; wash and coverage of a floodlight. A single DRI unit can provide a full 360 degrees of perimeter illumination while offering greater range and a larger area of coverage as compared to a floodlight of equal power. A programmable control system enables its operator to tailor the behavior of the DRI by selectively opening and closing the illumination. (The terms “open” and “close” are used here to denote only whether or not the DRI is projecting light, and are not meant to be suggestive of the method by which this effect is achieved.) By cycling the illumination open and closed at the same points during each rotation of the reflector, the appearance of a steady beam of light is produced. This beam of light can be widened to a full 360 degree field of coverage, or reduced to a narrow spotlight, simply by altering the duration of the open cycle. In this manner, single or multiple beams or sectors of illumination can be generated, all radiating from a single unit. The rotating optics are capable of executing rapid adjustments to the beam&#39;s vertical angle per rotation, allowing it to sweep targets located at differing elevations relative to the DRI. Furthermore, the rotating optics can make fine adjustments to the vertical spread of the beam per rotation. These basic functions can be recorded, and executed as presets, thereby allowing the precise illumination of static targets at various ranges and elevations. Additionally, a “lock, and dwell” function offers stationary (non-rotational) positioning of the light beam at any radial and vertical angle. The targeting of multiple lock points having various dwell durations can be programmed to run in a repeating sequence. 
         [0007]    A DRI is capable of simultaneously operating under at least two different protocols. By connecting a dedicated hand-held master controller or a computer, operational programs can be input and executed onsite. Concurrently, the DRI can track and receive commands in real time via radio frequency (RF). Upon activating a personal radio frequency controller/transmitter unit (hereafter referred to as a “transmitter”), an operative moving within a DRI&#39;s range can be painted with, illumination as the DRI tracks the; transmitter&#39;s location—the “follow spot” effect. Additionally, the operative can utilize the transmitter itself to program new patterns simply by signaling the DRI to begin recording the operator&#39;s movement through the area. Each DRI unit is able to track multiple transmitters. 
         [0008]    Operation can involve single or multiple DRI units. In a preferred embodiment, the deployment of three or more units insures full illumination coverage, as well as facilitating RF triangulation. In any given scenario, any number of units could be used, running various preset programs, and responding to transmitter signals on differing or identical frequencies. 
         [0009]    Many of the tactical functions of the DRI are based upon the differential illumination it generates. Observers experience this illumination as either a benefit or an impediment, and could thus be put into one of two categories, labeled “included” observers and “excluded” observers. The prominence of these advantages and disadvantages is dependent upon the techniques of DRI emplacement and site preparation, as well as ambient light levels and other environmental variables. 
         [0010]    DRIs are capable of being utilized specifically to visually impair excluded observers both by the sheer intensity of the light and by variable strobing effects, which can be tuned by the operator. Due to the radial coverage of the DRIs, this illumination can be difficult to avoid. Excluded observers experience this illumination as a wash of floodlight combined with multiple high-intensity spotlights aimed directly at their locations. 
         [0011]    Usage of a transmitter also enables the phenomenon of “negative illumination,” whereby the transmitter&#39;s operator is painted with “dark,” in contrast to the illumination covering the rest of the area. This provides the operator(s) with obscurity, or even invisibility. Operators using the transmitter function in this manner cannot be “blinded” by the DRIs, for the illumination is always closed as it sweeps across their position. The illumination thus appears to the operator(s) and other included observers as a smooth field of coverage with no evident source, without the deep shadows and harsh highlights that often accompany the single point illumination generated by a spotlight or floodlight. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of a DRI tower of the present invention; 
           [0013]      FIG. 2  is a side view, with portions cut away, of components of a DRI tower of the present invention; 
           [0014]      FIG. 3  is a close side view, with portions cut away, of the rotary head of a DRI tower of the present invention; 
           [0015]      FIG. 4  is a perspective view of a DRI master controller associated with a DRI tower; 
           [0016]      FIG. 5  is a perspective front view of a transmitter associated with a DRI tower; 
           [0017]      FIG. 6  is a perspective rear view of a transmitter associated with a DRI tower; 
           [0018]      FIG. 7  is a perspective view of the transmitter recharging station internal to a DRI tower, holding multiple docked transmitters; 
           [0019]      FIG. 8  is an aerial view of a single operational DRI tower providing a full 360 degrees of illumination; 
           [0020]      FIG. 9  is a side view of an operational DRI tower generating two separate beams of differing vertical trim and vertical angle; 
           [0021]      FIGS. 10-12  are aerial views of illumination and negative illumination scenarios that can be provided by the DRI tower(s) in association with one or more transmitters. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention. 
         [0023]    Referring now to  FIG. 1 , a perspective view of DRI tower  20  of the present invention is shown. In a preferred embodiment, tower  20  is a man-portable unit, the vertical dimension of which is intended to place the origin of the projected illumination just above the head, of an average adult. A single tower  20  could be used, but most circumstances will call for multiple tower  20  emplacement; three being an ideal minimum number, to insure full illumination, and to facilitate RF triangulation. Any greater number of towers  20  could be deployed, dependent upon the circumstances. Base  22  mounts four folding outriggers  24 . Outriggers  24  are lockable in an “up” position for storage and transport, or “down”, in which instance four screw jacks  26  can be used to manually stabilize and level tower  20 . Base  22  provides weatherproof connections  28  to route external electrical power and data transmission lines in, out, and through tower  20 . Central column  30  is attached to base  22  and supports rotary head  32 . Output illumination exits rotary head  32  via aperture  34 . Surrounding the midsection of central column  30  is skirt  36 , featuring transmitter recharging station access panel  38 , and master controller access panel  40 . Installed and locked into positions between skirt  36  and base  22  are four light engines  42 . Light engines  42  provide the source(s) of illumination, and are designed to be quickly interchanged with one another as required. An alternate embodiment relies upon a single light source located within central column  30 , and thus eliminates the need for four light engines  42 . However, the four light engine  42  configuration offers greater operational flexibility and reliability, and therefore is a preferred embodiment. 
         [0024]    Referring now to  FIG. 2 , a side view, with portions cut away, of components of tower  20  is shown. Skirt  36  houses transmitter recharging station  44  and storage space for master controller  46 . Rechargeable power cells  48  are capable of providing enough electrical power to operate tower  20  for a limited duration without connection to an external electrical power source RF transceiver  50  not only receives signal from any active transmitters  52  set to its frequency, but is also used to communicate with other towers  20  within its range, for purposes of transmitter localization, and to coordinate multi-tower  20  operation. Transceiver  50  can be tuned to a range of general, or restricted frequencies. Four power supplies  54  regulate electrical power delivery to their respective light engines  42 . Power supplies  54  may comprise ballasts, starters, microprocessors, voltage regulators, and other related components. In a preferred embodiment, light engines  42  are interchangeable among several variants, and can be pre-installed or exchanged on site by the operator to meet the requirements of the situation. For example, a light-emitting diode array offers an advantage of minimal power consumption, whereas extremely high-output illumination might require an incandescent, metal halide, or arc lamp combined with a reflector. Laser light, although potentially hazardous, may provide special purpose illumination, while infrared sources can be used for covert illumination. Any combination of these various types of light engines  42  can be installed, offering the operator a range of available types of illumination. The operator can then selectively activate one, two, three or all four light engines  42  to meet the needs of the situation. All light engines  42 , regardless of specific internal configuration, are identical in external size and shape, in order to facilitate interchange. As exemplified here, light engine  42 A comprises a light-emitting diode array, and light engine  42 B comprises an arc lamp. Terminal dock  56 A makes positive connection with contacts located on base  22  to convey data and electrical power from power supply  54 A to and from light engine  42 A. Light-emitting diode array  58  output is concentrated by collector  60 A, and focused upon first stage lens  62 A. The output of first stage lens  62 A is focused upon front surface reflector  64 A, and is thereby deflected at a 90° angle relative to the incoming light path. The illumination exits light engine  42 A at port  66 A, which is aligned with a similar opening into central column  30 . Light engine  42 B comprises parabolic reflector  68 , and arc lamp  70 , which receives power from power supply  54 B via terminal dock  56 B. Output illumination from arc lamp  70  is concentrated by collector  60 B, and focused upon first stage lens  62 B. Front surface reflector  64 B deflects illumination from first stage lens  62 B, directing it via port  66 B into central column  30 . Subsequently, outputs from all active light engines  42  are focused upon switcher assembly  72 , mounted inside central column  30 , and comprising four digital micromirror devices  74 . Each micromirror device  74  is capable of alternating between two states, as directed by master controller  46 : the open state deflects the light path from its respective light engine  42  into the second stage lens  76 . The closed state deflects the light path into one of four dedicated light-absorptive heat sinks  78  attached to the inner wall of central column  30 . Output from second stage lens  76  is focused directly into third stage lens  80 , which is mounted upon the axis of rotation inside hollow bore driveshaft  82 . In a preferred embodiment, third stage lens  80  is anamorphic, thereby outputting an oblong profile of illumination, focused upon main deflector  84 . The rotation of this aspherical profile is thus coupled to the rotation of hollow bore driveshaft  82 , causing the final output beam to assume a vertically columnar-profile, rather than a circular concentration of light. An alternate embodiment relies upon light shaping diffusion to narrow and elongate the illumination profile, eliminating third stage lens  80 , in which instance, output from second stage lens  76  is calibrated to focus through the rotating light shaping diffusion directly upon main deflector  84 . Motor  86  provides rotational force to rotary head  32  via hollow bore driveshaft  82 . Electrical energy and data passes to and from rotary head  32  via rotary electrical joint  88 . Preferably, motor  86  is capable of three different ranges of rotational rates, dependent upon the currently engaged mode of operation. In the “standard run” mode, tower  20  projects radial illumination, and the rotational rate of motor  86  is adjustable through a range of 800 rpm to 2400 rpm (approximate). The operator uses this variability to tune the output for best effect, as the situation demands. In the “loop record” mode, tower  20  records specific instructions from the operator In real time via master controller  46  or a computer. The rates of rotation in this mode range from 0.25 rpm to 10 rpm (approximate). In this instance, the variable rate of rotation permits the operator to slow the sweep of the beam, allowing precise adjustments to be made. In the “lock, and dwell” mode, motor  86  steps to preprogrammed points, and holds its position thereon for a preset duration. 
         [0025]    Referring now to  FIG. 3 , a close side view of rotary head  32 , with portions cut away, of tower  20  is shown. Third stage lens  80  focuses its output onto main deflector  84 . The light path is here deflected onto a horizontal plane. In a preferred embodiment, main deflector  84 , a lightweight front-surface reflector, pivots upon tilt yoke  90 , which also supports tilt micro-actuator  92 . Tilt micro-actuator  92  adjusts the main deflector&#39;s  84  angle as directed by master controller  46 , thereby altering the output light path&#39;s inclination and declination. Trim shutter  94  pivots upon trim yoke  96 , which also supports trim microactuator  98 . The cropping of the upper edge of the light path is executed by movement of trim shutter  94 , as directed by master controller  46 . This enables the vertical spread of the light output to be altered. Counterbalance  100  balances rotary head  32  and associated components upon the axis of rotation. The final output light path exits rotary head  32  through the optical glass of aperture  34 . 
         [0026]    Referring now to  FIG. 4 , a perspective view of a preferred embodiment of master controller  46  associated with tower  20  is shown. Master controller  46  is stored inside skirt  36  when not in use, and can be either wireless or hardwired to tower  20 . A single master controller  46  can interface with any number of towers  20  via discrete addressing. Main power button  102  is pressed to turn both tower  20  and master controller  46  on or off. Four light engine switches  104  select individual light engines  42  for programming. Transceiver settings button  106  displays tower&#39;s  20  operating RF frequency and other related settings. Main display screen  108  displays program numbers, light engine modes, status of transmitters, main power cell charge, and all other information such as diagnostics, global settings and calibration screens. Tilt thumbwheel encoder  110  controls tilt micro-actuator  92 , and thus the angle of main deflector  84 , thereby allowing vertical angling of the light beam during loop recording. Trim thumbwheel encoder  112  controls the behavior of trim micro-actuator  98  and pivoting trim shutter  94 , allowing the vertical dimension of the beam&#39;s profile to be changed during loop recording. Rotor rate encoder  114  controls the rotational rate of motor  86 . The ranges of this control are determined by the mode that tower  20  is currently executing: standard run, or loop record. Select/position thumbwheel encoder  116  is a dual function control. Its default mode selects menu items in main display screen  108 . Secondarily, when recording in lock, and dwell mode, it acts as a manual radial positioning control of the light beam. Light key  118  is pressed and held during loop recording to record an open illuminator state, and dark key  120  is pressed and held to record a closed state. Record key  122  is pressed to enter loop record mode, then pressed again to save working memory data as a preset. It is also used to record as a preset all current hold patterns that have been set up with transmitters  52 . Lock key  124  is pressed and held to enter lock and dwell mode, and pressed to set lock points at the radials selected with select position thumbwheel encoder  116 . (A dwell time is programmable for each lock point.) Pressed and held again to record lock point and dwell time data as a preset, and exits lock and dwell mode. Activate key  126  is pressed to activate the current preset, and pressed again to deactivate it. Preset selection keypad  128  is used to input numerical and typographical information, and to select presets by number. 
         [0027]    Master controller  46 , or a generic computer running dedicated software, provides the digital processing and control of the entire system. All system functions are accessed through master controller  46 , or a generic computer; some additional functions include:
       Beam spread at range: Sets the default horizontal spread of the beam at any given transmitter  52  range. This is an adjustment to the duration of the open or close cycle per revolution. For example, if the target is a person, the duration will be minimal, whereas if the target is larger, such as a vehicle, the duration can be extended.   Beam alignment on target: The target of transmitter  52  and the beam can be set to diverge in various ways. For example, the beam of light (or dark) can be set to align two degrees to the left of the target.   Address/slave/master: Configures which tower  20  issues commands, which towers  20  slave, and enables programming specific towers  20  from one master controller  46  by discrete addressing.   Priority: Determines which transmitters  52  take precedence of command or override, and how tower  20  resolves conflicts of transmitter  52  against preset program.   Synchronicity: To minimize or maximize strobe effects, multiple towers  20  can be set to rotate in variable phase relationships with one another.   Invert: A function that switches light to dark and vice-versa, could be useful in both programming and operation.       
 
         [0034]    Referring now to  FIG. 5 , a perspective front view of transmitter  52  associated with tower  20  is shown. Activate button  130  functions identically to the master controller&#39;s activate key  126 . Pressed to activate a current preset or working memory; pressed again to deactivate it. Hold button  132  is pressed and held to signal all towers  20  on the same frequency and within its range to record transmitter&#39;s  52  movements. This will result in either area illumination or area obscuration, depending upon transmitter&#39;s  52  target setting, and will be maintained independent of subsequent transmitter  52  motion. Lock button  134  is similar in function to the; master controller&#39;s lock, key  12   4 . Pressed to set a lock point with infinite dwell time at transmitter&#39;s  52  current bearing and vertical angle from all towers  20  sharing its frequency and within its range. Pressing it again results in the setting of a new lock point, deleting the previous one. Pressed and held to delete all active locks or holds, and resume normal (standard running speed) operation. Target selection switch  136  determines whether transmitter  52  is tracked in an open (light) or closed (dark) state, resulting in either a follow spot effect, or negative illumination. This also determines whether the hold function is tracked in an open or closed state. 
         [0035]    Referring now to  FIG. 6 , a perspective rear-view of transmitter  52  associated with tower  20  is shown. Power button  138  turns the transmitter on and off. Frequency selector  140  is used to select transmitter&#39;s  52  operating frequency. Display screen  142  shows transmitter&#39;s  52  remaining power cell charge, currently selected frequency, and the current RF signal strength. Recharge hub  144  couples with transmitter recharging station jack  146  to facilitate the storage and recharging of unused transmitters  52 . 
         [0036]    Referring now to  FIG. 7 , a perspective; view of transmitter recharging station  44  with multiple docked transmitters  52  within tower  20  is shown. Transmitter station access panel  38  has been removed to expose transmitter recharging station  44 , which provides constant direct current to multiple jacks  146 , allowing the recharging and storage of transmitters  52  when not in use. The individual charge status of each transmitter  52  is displayed here, and can be monitored at master controller  46  or a computer. Four transmitters  52  are shown docked and recharging, and two jacks  146  are shown without, connected transmitters  52 . 
       OPERATIONAL EXAMPLES OF THE INVENTION 
       [0037]    A DRI is able to produce a variety of optical effects, many of which can be combined to produce behavior of greater complexity. Some effects include:
       Full 360 degree perimeter illumination   Multiple static sector illumination or obscuration   Multiple static point illumination or obscuration   Multiple active tracking illumination (follow spot effect)   Multiple active tracking obscuration (negative illumination)   Dazzling and impairment of designated personnel and optical equipment   Local optical tagging and tracking of designated targets   Covert tagging, tracking, and illumination (infrared)   Selective illumination of an area with minimal impact upon designated personnel&#39;s night vision.       
 
         [0047]    A DRI can generate the long distance illumination of a spotlight combined with the area coverage of a floodlight. Referring specifically to  FIG. 8 , an aerial view of a single tower  20  providing night perimeter illumination is shown, although this operational configuration can be used for other purposes. A flat 360 degree perimeter sweep of this type is the default running mode of tower  20 , and therefore would simply need to be activated, and the rotational rate adjusted for best results. We will briefly review how it might be programmed onsite, using master controller  46  or a computer. In a preferred embodiment, the operator would first select a preset slot to record into; in this example, we will use preset  10 . The operator presses record key  122 , causing the illumination to open, and motor  86  to begin rotating in loop record mode (0.25 rpm to 10 rpm). After the beam has made at least one full rotation, record key  122  is pressed again, thus saving the data as preset  10 . Now, this preset may be activated and deactivated by pressing activate key  126  at master controller  46 , or via transmitter  52 . Alternatively, a flat perimeter sweep could be programmed by transmitter  52  signal. Walking transmitter  52  through one full orbit around tower  20  while keeping hold button  132  depressed will cause tower  20  to remain in a continuously open state. (Assuming that transmitter  52  is set to target: light). This data will remain as a “working memory” which, unless it is saved as a preset, will be deleted when a new preset is called up, or when tower  20  is turned off. 
         [0048]    Referring now to  FIG. 9 , a side view of tower  20  in operation is shown. The rotating beam of light is only open at radials  148 A and  148 B. These two different light paths have been set to diverge from horizontal using the tilt thumbwheel encoder  110 , and each has been cropped vertically by use of the trim thumbwheel encoder  112 . 
         [0049]      FIGS. 10-12  are aerial views of illumination and obscuration scenarios that can be provided by the DRI system using a combination of preset programs and active transmitter  52  tracking and control. While the first of these examples depicts the effect, generated by a single tower  20 , in the preferred embodiment, three towers  20  is an ideal effective minimal deployment. 
         [0050]    Referring specifically to  FIG. 10 , an aerial view of a single tower  20  positioned in a street between buildings  150 A and  150 B is shown. Tower  20  is illuminating only the targeted areas, namely, doorway  152  of building  150 A, street approach  154  from the east, and windows  156 A and  156 B of building  150 B. This type of selective illumination can offer several tactical advantages over general floodlighting: included observers located in the dark areas are obscured, and can preserve their night vision, while their areas of concern are visually highlighted by precision lighting. Excluded observers located in the light areas are rendered conspicuously visible, and are subject to the effects of a blinding and disorientating spotlight locked on their positions. 
         [0051]    Let&#39;s analyze how this scenario was programmed after tower  20  had been set in place. In the preferred embodiment, the operator, using a computer or master controller  46 , first selects a preset slot in which to record. The operator then presses record key  122 , which causes the tower  20  to enter loop record, mode—the illumination opens and motor  86  begins slowly rotating. The operator allows the beam of light to sweep past doorway  152 , across eastern street approach  154 , and then uses tilt thumbwheel encoder  110  to angle the beam of light up to second story windows  156 A and  156 B. After the beam has transited across windows  156 A and  156 B, the operator uses tilt thumbwheel encoder  110  to return the beam to a horizontal plane. Now, all subsequent rotations of the beam will follow these vertical movement, instructions, unless a change is made. Now the operator uses trim thumbwheel encoder  112  to crop the upper edge of the light, beam so that it matches the vertical dimension of the various targets: doorway  152 , street approach  154 , and windows  156 A and  156 B. Finally, the operator uses light key  118  and dark key  120  to close the illumination except, during the beam&#39;s transit across the four targets. The operator may use rotor rate encoder  114  to slow the beam further for the fine-tuning of the program. Any errors made during loop recording can be overwritten during subsequent revolutions of the beam. When the operator is satisfied with the program, he again presses record key  122  to save it as a preset. Pressing activate key  126 , or transmitter&#39;s activate button  130 , will now execute this preset. 
         [0052]    Although the above example has direct tactical relevance, it could also pertain to architectural lighting; providing, for example, illumination of selected architectural features while simultaneously preventing light spill onto doorways and windows. This type of architectural lighting could be instantly converted to other purposes, simply by changing presets. It could also be responsive to motion sensors, or to select personnel, such as residents, security personnel, or law enforcement officers. 
         [0053]    Lighting of commercial advertising, such as banners and billboards could also be derived from this example, for the various presets and sequences of presets could give dynamic lighting to otherwise static imagery. This type of lighting may not be subject to legal restriction in the same way that full-motion video billboards are in many areas. 
         [0054]    A DRI&#39;s differential illumination is applicable also to theatrical and concert production, enabling the lighting director to conceal and reveal set changes or selective areas of a stage, as well as offering strobe, wash, and spotlight functions. Potential benefits to stage magic and illusion production are evident. Referring now to  FIG. 11 , an aerial view of an operating deployment of three towers  20 A,  20 B, and  20 C is shown. Areas without shading receive illumination from all three; towers  20 . Lightly shaded areas receive illumination from two towers  20 , and blacked out areas receive no illumination. The relative positioning of towers  20 A,  20 B, and  20 C is subject to the circumstances of deployment, the desired effects, and environmental factors. For instance, multiple towers  20  could be deployed in a linear arrangement, with excluded observers on one side, and included, observers on the other. The arrangement shown is arbitrary; used here to illustrate the active tracking of transmitter  52 . In the preferred embodiment, no programming is required, to configure this scenario, as towers  20 A,  20 B, and  20 C are all in their default perimeter sweep mode. Operative X  158  need only take transmitter  52  from transmitter recharging station  44 , turn it on, verify that its RF frequency matches towers&#39;  20 A,  20 B, and  20 C frequencies, set transmitter&#39;s  52  targeting to dark, and press activate button  130 . Operative X  158  is now free to move about the illuminated area, remaining always within a “box of shadow.” This will provide operative X  158  with complete illumination of the surroundings, without risk of being blinded by towers  20 A,  20 B, and  20 C, for they are always in a closed state as they sweep across operative X&#39;s  158  location. Excluded observers  160 A,  160 B, and  160 C are rendered conspicuously visible, and are subject to the impairment and disorientation caused by three high intensity spotlights aimed at them. The differential illumination produced in this scenario, enhanced by site preparation and good technique, can result in operative X  158  being rendered invisible to excluded observers  160 A,  160 B, and  160 C. Located also in the illuminated areas are excluded operative Y  162 , and guard post  164 . 
         [0055]    Referring now to  FIG. 12 , the previous deployment of three towers  20 A,  20 B, and  20 C is again shown. Areas with no shading receive illumination from three towers  20 . Lightly shaded areas receive illumination from two towers  20 , and darker areas receive illumination from one tower  20 . Blacked out areas receive no illumination. The towers  20  continue to track and negatively illuminate operative X  158 , and now negatively illuminate transmitter  52  protected operative Y  162 , while simultaneously obscuring guard post  164  via preset program. This demonstrates how multiple towers  20 A,  20 B, and  20 C can track multiple moving transmitters  52 , while simultaneously executing preset programs. Excluded observers  160 A and  160 B are exposed to direct illumination from towers  20 A,  20 B, and  20 C. Excluded observer  160 C, located in a partially shadowed region, is still illuminated by towers  20 A and  20 B. 
         [0056]    The further versatility of the DRI is demonstrated by contemplating some of its other possible configurations. Several DRIs could be part of a permanent installation, in which case, it would be advantageous to integrate them with the infrastructure. For example, consider an indoor operation with elevated security measures, such as a checkpoint. The DRIs have been connected with the building&#39;s interior lighting systems, but now remain unobtrusive, operating in standby status. The personnel manning this checkpoint wear transmitters  52 , powered on, and set to target: dark. If a threatening situation arises, any of the personnel may choose to activate his transmitter  52 , bringing all DRIs out of standby while simultaneously cutting the building&#39;s normal lighting. This would instantly fill the space with brilliant eye-level illumination, exempting only the checkpoint personnel who, protected by their transmitters  52 , remain obscured, and are so offered an immediate advantage in dealing with the situation. 
         [0057]    The DRI can be adapted to fit emergency response vehicles. Consider one scenario, in which several police vehicles are responding to a “shots fired” situation. Even as the officers arrive on scene, their vehicle rooftop DRIs could be active, providing full perimeter illumination. If the situation merits it, one officer could remain in his vehicle to program all of the DRIs on site, via discrete addressing. When the officers do exit their vehicles, they carry frequency-matched transmitters  52 , insuring that they will always remain obscured, and will never be impaired by their own lighting. By pressing transmitter lock button  134 , an officer could choose to ‘mark’ a detained suspect, suspicious object, or specific location with the concentrated non-rotational output of some or all DRI units present. 
         [0058]    Consider another scenario: the roadside traffic stop—a routine, yet potentially dangerous situation. Here, a preset program that illuminates ahead, and the entire right side of the suspect vehicle would be ideal. This would provide illumination of the vehicle, as well as the entire field of view on the passenger&#39;s side. This program would offer the broadest possible field of illumination, while leaving traffic approaching from either direction unimpaired by bright spotlights. Note that in the above situations, and many others of a tactical nature, personnel can be substantially relieved of the distraction of handling and aiming their own hand-held or weapon-mounted illuminators. 
         [0059]    Several incidental effects should be noted:
       The four light engine  42  configuration allows the option of lighting sectors with differing illumination, For instance, half a field could be illuminated by arc light, one quarter by infrared light-emitting diode, and one quarter by green light. Transmitters  52  could also be tracked using any single or combination of multiple light engines  42 .   If transmitters  52  have a significant range, then tower  20  could be used as a visual beacon by anyone carrying such a transmitter  52 . Conversely, tower  20  could be used as a visual indicator of the bearings of active transmitters  52 .   Due to the horizontal and radial nature of the light beam, it could be utilized as a sort of emergency aviation beacon, capable of indicating compass directions and other basic information visually.       
 
         [0063]    The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention.