Patent Publication Number: US-2009219961-A1

Title: Laser Systems and Methods Having Auto-Ranging and Control Capability

Description:
FIELD OF THE INVENTION 
     The present disclosure is directed to laser control systems, and more particularly, to laser systems and methods having an ability to automatically adjust a laser output based on a range to an object detected within a field of view to deliver a controlled exposure to the object. 
     BACKGROUND OF THE INVENTION 
     Laser systems are used in a wide variety of civilian and military applications. Laser systems may be used, for example, for illuminating objects, determining distances (or ranging), detecting events, targeting objects, communications, and for a wide variety of other purposes. Recently, high-intensity laser illumination (or “dazzling”) has been used in various security-related applications (e.g. military checkpoints, border crossings, access control stations, etc.) and has proven to be an effective deterrent of potentially-hostile activity, thereby promoting stability and saving lives. 
     As is generally known, laser systems are not entirely without risk to human vision. Many applications require laser systems to be operated at power levels that may be considered detrimental to human vision. One generally-accepted criterion for assessing whether a laser is operating at a power level detrimental to human vision is known as the Nominal Ocular Hazard Distance (NOHD). Because the power density of a laser&#39;s output decreases with increasing distance from the laser due to beam spreading, a particular laser power level may be considered safe at longer ranges, but may become hazardous within a certain operating range near the laser. The NOHD defines a near-range exposure danger zone for human vision. 
     In many situations that involve relatively high power laser systems, protection protocols and systems have been developed that attempt to minimize harmful exposure to laser irradiation that may be detrimental to human vision. Such protocols and systems may include, for example, mandatory use of laser-safe goggles, laser beam enclosures (particularly within the NOHD), door-lock systems that automatically shut off laser systems upon entry, and various other safety measures. Although desirable results have been achieved, there are situations where the use of such conventional safety systems and protocols may be impractical or impossible. 
     SUMMARY 
     The present disclosure teaches laser systems and methods having an ability to automatically determine a range to an object detected within a field of view, and to automatically adjust the laser (e.g. intensity, output power, divergence, etc.) to reduce a potential risk to the object. Embodiments of systems and methods in accordance with the teachings of the present disclosure may advantageously adjust the laser to deliver a specific exposure to the target, and thereby enhance the safety of laser operations in a variety of conditions and circumstances where conventional safety methods and protocols are impractical or impossible to implement. In some embodiments, an operator may control a desired effect the laser system will have on a target within a field of view (e.g. dazzle, hail, warn, etc.), while an auto-ranging and control capability of the laser system promotes safety by automatically adjusting the laser to control the exposure of the target to be less than a maximum permissible exposure (MPE). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present disclosure are described in detail below with reference to the following drawings. 
         FIG. 1  is an exemplary environment having a laser system in a first operating condition in accordance with an embodiment of the present disclosure. 
         FIGS. 2-4  show the exemplary environment of  FIG. 1  having the laser system in second, third, and fourth operating conditions, respectively. 
         FIG. 5  is a schematic view of the laser system of  FIG. 1  in accordance with another embodiment of the present disclosure. 
         FIG. 6  is an exemplary laser power time history of the laser system of  FIG. 5  in accordance with an alternate embodiment of the present disclosure. 
         FIG. 7  is a schematic view of a laser system in accordance with another alternate embodiment of the present disclosure. 
         FIG. 8  is an exemplary environment having a laser system in accordance with yet another embodiment of the present disclosure. 
         FIG. 9  is a process for operating a laser system in accordance with a further embodiment of the present disclosure. 
         FIG. 10  is a schematic view of a laser system in accordance with yet another embodiment of the present disclosure. 
         FIG. 11  is a table of some of the potential operating conditions that may be encountered by embodiments of laser systems in accordance with the present disclosure, including the laser system of  FIG. 10 . 
         FIG. 12  is a process for operating a laser system in accordance with another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure is directed to laser systems and methods having an ability to automatically adjust a laser output based on a range to an object detected within a field of view. Many specific details of certain embodiments in accordance with the present disclosure are set forth in the following description and in  FIGS. 1-12  to provide a thorough understanding of such embodiments. One skilled in the art, however, will understand that the present invention may have additional embodiments, or that the invention may be practiced without several of the details described in the following description. 
       FIG. 1  is an exemplary environment  100  having a laser system  110  in accordance with an embodiment of the present disclosure. In a first operating condition  103 , the laser system  110  directs a laser beam  120  along a beam axis  122  toward a target  102 . The laser beam  120  may be a pulsed or non-pulsed laser beam  120 . As depicted by the gradually-decreasing shading of the laser beam  120 , an intensity (or power density) of the laser beam  120  generally decreases with increasing distance from the laser system  110  (e.g. due to beam spreading, absorption, etc.). At least part of the laser beam  120  that impinges on the target  102  is reflected as target reflections  124  (specular or non-specular) from the target  102 . In the first operating condition  103 , an intermediate object  104  (e.g. a bystander) is positioned generally outside of the laser beam  120 . 
     Although the exemplary environment  100  shown in  FIG. 1  depicts the target  102  as a vehicle, it will be appreciated that in alternate embodiments, the target  102  may be any type of object (military or civilian) that may be illuminated with the laser system  110 , including a person, a building, a natural landscape, a watercraft, an aircraft, or any other suitable object. Similarly, the laser beam  120  may be configured for a variety of purposes, including, for example, to illuminate the target  102 , to “dazzle” the target  102  (or occupants thereof), to “hail,” “warn,” or “disrupt” the target  102 , for targeting or aiming a weapon system (not shown), for inflicting damage on the target  102 , or for any other suitable purpose. 
     In the embodiment shown in  FIG. 1 , the laser system  110  includes a laser source  112  and a beam directing assembly  114  that cooperatively generate and condition the laser light that ultimately forms the laser beam  120 . A ranging system  150  is configured to determine a distance (or range) D T  to the target  102 . A control system  116  is configured to transmit control signals to one or more of the other components of the laser system  110 , including the laser source  112  and the beam directing assembly  114 . The control system  116  is also configured to receive signals from one or more of the other components of the laser system  110 , including the ranging system  150 . In some embodiments, the laser system  110  also includes a power source  118  (e.g. a battery), such as may be desired for a portable laser system, however, in alternate embodiments, the laser system  110  may rely on an external power source (not shown). 
     The ranging system  150  may be based on a variety of conventional ranging methods and techniques. For example, in some embodiments, the ranging system  150  may be configured to receive at least a portion of the target reflections  124  from the target  102 , and may include a time-of-flight (TOF) system that clocks the time required for a portion of the laser beam  120  (e.g. a laser pulse) emitted by the laser system  110  to travel to the target  102 , reflect from the target  102 , and travel back to the ranging system  150 , given by: 
       Time=(2 D   T   /c   air )=6.681 nsec/m  (1) 
     where c air  is the speed of light through air, and D T  is a distance between the laser system  110  and the target  102  (or target distance). Thus, the target distance D T  may be determined by: 
         D   T =(Time  c   air )/2=0.1497 m/nsec  (2) 
     In alternate embodiments, the ranging system  150  may be based on other suitable ranging methods, including triangulation, modulation, or any other ranging technologies. In further embodiments, the ranging system  150  need not be based on any portion of the laser beam  120  (e.g. a laser pulse), but rather, may be independent from the laser beam  120 . For example, in some embodiments, the ranging system  150  may be based on sonic (or acoustic) signals, ultrasonic signals, non-laser light signals, including signals from any suitable portion of the electromagnetic spectrum, imaging technologies, or even various non-signal-based technologies for determining range and distance (e.g. Global Positioning System technologies, physical contact sensors, etc.). Representative examples of suitable ranging technologies that may be used by the ranging system  150  include, but are not limited to, those technologies generally described in U.S. Pat. No. 7,317,872 issued to Posa et al., U.S. Pat. No. 7,271,761 issued to Natsume et al., U.S. Pat. No. 7,075,625 issued to Abe, U.S. Pat. No. 7,154,591 issued to Muenter, U.S. Pat. No. 6,697,146 issued to Shima, and U.S. Pat. No. 5,336,899 issued to Nettleton et al. 
     With continued reference to  FIG. 1 , a standoff distance D S  is shown. The standoff distance D S  may depend on various factors of the environment  100 , such as the operating conditions and purpose of the laser beam  120 , the range and identity of the target  102 , the presence and identity of the bystander  104 , or any other factors. In some embodiments, for example, the standoff distance D S  may be based on a desire to avoid a potential hazard to human vision. More specifically, the standoff distance D S  may be approximately equal to (or based on) a Nominal Ocular Hazard Distance (NOHD). The NOHD may be defined as a distance from the laser system  110  where a maximum permissible exposure (MPE) for human vision is exceeded. Of course, in alternate embodiments, other criterion for establishing the standoff distance D S  may be used. For example, because non-human species (e.g. animals, insects, etc) may have a visual acuity or sensitivity that is different from humans, the standoff distance D S  may be established based on an ocular hazard distance for such non-human species. Alternately, the standoff distance D S  may be established based on maximum exposure limits of nearby machines, sensors, electronics, or other systems, or may be established based on factors that are unrelated to vision (e.g. non-ocular factors). 
     In some embodiments, operation of the laser system  110  may begin by activating the laser system  110  to provide the laser beam  120  directed toward the target  102  to perform the desired functionality. The standoff distance D S  may be established by the operating conditions of the laser system  110 , and may initially be assumed to compare favorably with the target distance D T . The ranging system  150  may then determine the target distance D T , either simultaneously or sequentially with the generation of the laser beam  120 . 
     The laser system  110  may then compare the target distance D T  with the standoff distance D S  (e.g. using the control system  116 ). If the target distance D T  compares favorably with the standoff distance D S  (e.g. target distance D T  exceeds standoff distance D S ), the laser system  110  may continue providing the laser beam  120  without making any adjustments to the laser system  110 . Alternately, if the target distance D T  compares unfavorably with the standoff distance D S  (e.g. target distance D T  does not exceed standoff distance D S ), the laser system  110  may perform adjustments to the operating conditions of the laser system  110  (and thus the standoff distance D S ) until a favorable comparison is achieved. 
     More specifically, in some embodiments, the laser system  110  (e.g. using the control system  116 ) may controllably adjust one or more portions of the laser system  110  to adjust the laser beam  120 , and thus the standoff distance D S , until the target distance D T  meets or exceeds the standoff distance D S . For example, the control system  116  may adjust an output power of the laser source  112 , or one or more portions of the beam directing assembly  114  (e.g. beam conditioning optics, attenuators, etc.), or both the laser source  112  and the beam directing assembly  114 , to adjust the standoff distance D S . In further embodiments, other portions of the laser system  110  may be adjusted to provide a desired standoff distance D S . As operations continue, the laser system  110  may continue to monitor the target distance D T , and continue to controllably adjust the laser operating conditions so that the standoff distance D S  continues to compare favorably with (e.g. less than) the target distance D T . 
     In some embodiments, the laser system  110  may begin operating in a different way. More specifically, the operation of the laser system  110  may begin by having the ranging system  150  determine the target distance D T  (e.g. by “pinging” the target  102 ). Based on the target distance D T , the laser system  110  may initiate the laser beam  120  so that the target distance D T  compares favorably with the standoff distance D S . For example, in some embodiments, the standoff distance D S  may be established based on a desire to avoid potential hazards to human vision. In such cases, the standoff distance D S  may be based on the NOHD, and the laser system  110  may controllably generate the laser beam  120  so that the standoff distance D S  is less than (or equal to) the target distance D T . 
     In still other embodiments, the operating conditions may be set so that the standoff distance D S  may initially assume a reasonably small value. The laser system  110  may then be operated to generate and direct the laser beam  120  toward the target  102 , and the ranging system  150  may be operated, either simultaneously or sequentially with the presence of the laser beam  120 , to determine the target distance D T . The laser system  110  (e.g. via the control system  116 ) may determine whether the target distance D T  compares favorably or unfavorably with the standoff distance D S , and may perform adjustments to laser beam  120  accordingly. 
       FIG. 2  shows the laser system  110  in a second operating condition  105  wherein the intermediate object (or bystander)  104  has recently moved into the laser beam  120 . In the second operating condition  105 , at least part of the laser beam  120  that impinges on the intermediate object  104  is reflected as intermediate reflections  126 . The ranging system  150  automatically determines an intermediate distance D I  between the laser system  110  and the intermediate object  104 , and the control system  110  compares the intermediate distance D I  with the standoff distance D S . In the second operating condition  105  shown in  FIG. 2 , the intermediate distance D I  is less than the standoff distance D S , and thus compares unfavorably with the standoff distance D S . More specifically, in some embodiments, the bystander  104  has entered the NOHD portion of the laser beam  120  (i.e. the near-range exposure danger zone for human vision). 
     In a third operating condition  107  shown in  FIG. 3 , the laser system  110  has automatically adjusted the standoff distance D S  based on the presence of the intermediate object  104 . More specifically, the laser system  110  has automatically adjusted one or more portions of the laser system  110  to provide an adjusted laser beam  130  such that the intermediate distance D I  meets or exceeds the standoff distance D S . Although the third operating condition  107  shown in  FIG. 3  depicts that laser system  110  as providing the adjusted laser beam  130 , it will be appreciated that in some embodiments, it may be necessary to completely shut down the laser system  110  in the third operating condition  107  so that the intermediate distance D I  compares favorably with the standoff distance D S . 
     In a fourth operating condition  109  shown in  FIG. 4 , the bystander  104  has moved out of the laser beam  130 . The ranging system  150  automatically determines that the bystander  104  is no longer within the laser beam  130  (or other specified field-of-view), and that the closest object within the laser beam  130  is once again the target  102 . Based on the target distance D T , the laser system  110  automatically adjusts the laser beam  120  (and thus the standoff distance D S ) back to the initial operating condition  103 . In the fourth operating condition  109 , the laser system  110  continues to provide the laser beam  120  to perform the desired function, and may continue to monitor and adjust the operating conditions so that the target distance D T  compares favorably with the standoff distance D S . 
     Embodiments of systems and methods in accordance with the present disclosure may provide substantial advantages over conventional laser systems. For example, systems and methods having an ability to automatically adjust a laser output based on a range to an object detected within a field of view may promote safety in a wider range of operating environments in comparison with conventional systems. Because such systems may automatically detect the presence of an intermediate object, and may automatically adjust the laser system to ensure that the intermediate object is outside the standoff distance, embodiments in accordance with the present disclosure may enhance the safety of laser operations in a variety of conditions and circumstances where conventional safety methods and protocols are impractical or impossible to implement. Embodiments in accordance with the present disclosure may also enhance the safety of laser operations at substantially-reduced cost, and with improved reliability, in comparison with conventional alternatives. 
     It will be appreciated that a variety of suitable embodiments of the laser system  110  may be conceived that provide the desired operability in accordance with the teachings of the present disclosure. For example,  FIG. 5  is a schematic view of one possible embodiment of the laser system  110  of  FIG. 1 . In this embodiment, the laser source  112  includes a pulse generator  160  coupled to a laser driver  162 . A laser diode  164  is driven by the laser driver  162  to provide a laser light  166  to the beam directing assembly  114 . One or more conditioning optics  168  of the beam directing assembly  114  condition the laser light  166  to provide a collimated laser beam along the beam axis  122 . 
     In some implementations, the components of the laser system  110  may be configured to provide a pulsed laser light  166  at controlled current levels. For example, the pulses of laser light  166  may be adjustably varied within a range of approximately 10 nsec to approximately 50 nsec. Of course, in alternate embodiments, pulses of any other suitable duration may be employed. 
     With continued reference to  FIG. 5 , in this embodiment, the ranging system  150  receives a reflected portion  172  of the emitted laser beam that reflects from the distal target  102  or the intermediate object  104 . The reflected portion  172  passes through an optical bandpass filter  174  and one or more conditioning optics  176  of the ranging system  150  before impinging upon a detector  178 . In some embodiments, the detector  178  may include a photodiode, an avalanche photodiode, a photo-detector, or any other suitable detection device. Output signals from the detector  178  may be conditioned by an amplifier  180  and by an automatic gain control (AGC) component  182 . The AGC component  182  conditions the output signals so that, despite variations in the input level (e.g. the reflected portion  172 ), the average level of the output from the AGC component  182  are approximately at a predetermined value (or within a predetermined range). A timer (or counter)  184  receives the output signals from the AGC component  182  and determines the target distance D T  using, for example, Equation (2) above. 
       FIG. 6  is an exemplary laser power time history  200  of the laser system  110  of  FIG. 5 . In this embodiment, the time history  200  includes a series of alternating illumination pulses  202  and ranging pulses  204 . The ranging pulses  204  are of higher intensity and shorter duration than the illumination pulses  202 , and are configured to operate as the source of the reflected signals  172  received by the ranging system  150 . Similarly, the illumination pulses  202  are configured to perform the intended purpose of the laser system  110  with respect to the target  102  (e.g. illuminate, “dazzle,” aim, damage, etc.). 
       FIG. 7  is a schematic view of a system  300  in accordance with another alternate embodiment of the present disclosure. In this embodiment, the system  300  includes a laser component  310  and a ranging component  350  powered by an external power source  305 . The laser component  310  includes a laser source  112  and a beam directing assembly  114  having substantially the same structural components and functionality as described above with respect to  FIG. 5 . A controller  320  controls the laser source  112  and the beam directing assembly  114  to provide a laser output  122  toward a distal target (not shown). 
     The ranging component  350  is operatively coupled to the laser component  310  and includes a signal generation portion  360 , a signal detection portion  370 , and a distance determination portion  380 . In this embodiment, the signal generation portion  360  includes a source  362  that emits signals  364  into a signal conditioner  366 . A ranging signal  368  is transmitted from the signal generation portion  360  toward a distal object within a field of view of the ranging component  350 . 
     As further shown in  FIG. 7 , a portion of the ranging signal  368  is reflected back from the distal object as a return signal  372 . The return signal  372  passes through a first signal conditioner  374  (e.g. a filter), a second signal conditioner  376  (e.g. focusing optics), and arrives to a detector  378 . The distance determination portion  380  receives an output from at least the signal detection portion  370  and determines the range to the distal object. The ranging component  350  outputs the range to the laser component  310  (e.g. to the controller  320 ), and continues performing ranging of distal objects within the field of view. Thus, the above-described advantages of laser systems and methods having an ability to automatically determine a range to an object detected within a field of view, and to automatically adjust the laser (e.g. illumination intensity, etc.) to reduce a potential risk to the object, may be achieved using a system  300  having separate laser and ranging components  310 ,  350  that cooperatively perform the desired functionality. 
       FIG. 8  is an exemplary environment  400  having a laser system  410  that includes a ranging system  450  in accordance with yet another embodiment of the present disclosure. The laser system  410  directs a laser beam  420  along a beam axis  422  toward a target  402 . At least part of the laser beam  420  that impinges on the target  402  is reflected as target reflections  424  (specular or non-specular) from the target  402  back toward the laser system  410 . 
     In this embodiment, the ranging system  450  monitors for the presence of objects within a field of view  430  that is larger than (and substantially inclusive of) the laser beam  420 . For example, in addition to the target  402 , a first intermediate object  404  (e.g. a vehicle) and a second intermediate object  406  (e.g. a person) are situated at least partially within the field of view  430 . Both intermediate objects  404 ,  406  are outside the laser beam  430 . 
     Ranging signals  452  are emitted by the ranging system  450  within the field of view  430 . First reflected signals  454  are reflected from the first intermediate object  404 , second reflected signals  456  are reflected from the second intermediate object  406 , and target reflected signals  458  are reflected from the target  402 . The ranging system  450  receives at least a portion of the reflected signals  454 ,  456 ,  458 , and determines a first distance D 1  to the first intermediate object  404 , a second distance D 2  to the second intermediate object  406 , and a target distance D T  to the target  402 . These distances may then be compared with a standoff distance D s , and necessary adjustments (if any) may be made, as described above. 
     Embodiments of systems and methods in accordance with the present disclosure having a ranging system that operates using a field of view that is larger than an associated laser beam may provide additional advantages. Because the field of view extends laterally beyond the laser beam, the laser system may detect intermediate objects, and make necessary adjustments to the laser beam, before the intermediate objects actually enter the laser beam. This aspect may be a valuable aspect in some applications, particularly for relatively high power laser applications. 
       FIG. 9  is a process  500  for operating a laser system in accordance with a further embodiment of the present disclosure. In this embodiment, the process  500  includes operating a laser system to provide a laser beam toward a target at  502 . The operating conditions of the laser system establish a standoff distance. At  504 , a ranging system is operated to determine a distance to a nearest object within a field of view (FOV). In some embodiments, the field of view is coincident with the laser beam. Alternately, the field of view may be larger than the laser beam. The ranging system may be operated simultaneously or sequentially with the laser system. In some embodiments, the ranging system provides its own ranging signals, while in other embodiments, the ranging system uses reflected laser light generated by the laser system. 
     At  506 , the process  500  determines whether the distance to the nearest object within the field of view compares favorably with the standoff distance. For example, in some embodiments, the standoff distance is based on the NOHD portion of the laser beam (i.e. the near-range exposure danger zone for human vision), and the distance to the nearest object compares favorably when it is greater than the standoff distance, and compares unfavorably when it is not greater than the standoff distance. If the comparison is favorable (at  506 ), then the process  500  returns to  502  and continues performing the above-noted activities indefinitely ( 502  through  506 ). 
     On the other hand, if the distance to the nearest object within the field of view compares unfavorably with the standoff distance (at  506 ), then the process  500  adjusts one or more of the laser operating conditions at  508 . For example, in some embodiments, a control system may controllably adjust one or more of a laser source and a beam directing assembly in order to adjust a standoff distance of the laser beam. 
     Next, after performing the adjustment at  508 , the process  500  may determine whether a limit condition has been reached at  510 . For example, the process  500  may determine whether some type of lower (or minimum) operating limit has been reached on a laser operating condition (e.g. output power, divergence angle, etc.) so that continued operation of the laser is no longer practical or suitable for its intended purpose. If the determination at  510  is affirmative, the process  500  proceeds to shutdown at  512 . Alternately, if no limit condition has been reached (at  510 ), then the process  500  returns to  502 , and continues performing the above-described actions ( 502  through  510 ) indefinitely. 
     It will be appreciated that the process  500  is one possible implementation in accordance with the present disclosure, and that the present disclosure is not limited to the particular process implementations described herein and shown in the accompanying figures. For example, in alternate implementations, certain acts need not be performed in the order described, and may be modified, and/or may be omitted entirely, depending on the circumstances. Moreover, in various implementations, the acts described may be implemented by a computer, controller, processor, programmable device, or any other suitable device, and may be based on instructions stored on one or more computer-readable media or otherwise stored or programmed into such devices. In the event that computer-readable media are used, the computer-readable media can be any available media that can be accessed by a device to implement the instructions stored thereon. 
     Embodiments of systems and methods in accordance with the present disclosure may be configured to operate while the laser system is moving, the objects within the field of view are moving, or both. For example,  FIG. 10  is a schematic view of a laser system  610  in accordance with still another embodiment of the present disclosure. The laser system  610  includes many of the same components as the laser system  110  described above with reference to  FIG. 1  (e.g. laser source  112 , beam directing assembly  114 , control system  116 , power source  118 ). In this embodiment, however, the laser system  610  includes a laser motion determination component  620  and a target state determination component  650 . 
     The laser motion determination component  620  may be configured to monitor and detect motion of the laser system  610  in one or more of the customary six-degrees of freedom of motion, including one or more of the translational motion components (e.g. x, y, and z axis) and the rotational motion components (e.g. roll, pitch, and yaw). The laser motion determination component  620  may include a variety of known components (e.g. accelerometers, gyroscopes, GPS devices, etc.) for sensing one or more components of the translational and/or rotational motion of the laser system  610 . The information collected by the laser motion determination component  620  may then be provided to the control system  116 . 
     More specifically, in some embodiments, the laser motion determination component  620  may include a single or multi-axis accelerometer or gyroscope to detect motion of the laser system  610 , and may be configured to automatically adjust, attenuate, or even shut-down the laser system  610  until motion of the beam has slowed to the point where the target state determination component  650  (or other rangefinder part of the system) has time to acquire the target and obtain a valid range estimate. For example, in some particular embodiments, the state determination (or rangefinder) component may have a range acquisition rate within a range of approximately 10&#39;s to 100&#39;s of Hz, while the motion of the beam at 100+ meters while swinging the beam around could be extremely fast (100+ m/s). This scenario could address the ‘horseplay’ problem where users in the field are swinging the lasers around and not controlling/aiming them properly like a weapon. 
     Similarly, the target state determination component  650  may be configured to determine the range (or distance) D T  to targets or objects within the field of view of the laser system  610  as described above, and may also be configured to determine one or more aspects of the motion of such targets or objects. For example, using known techniques and technologies, including those described above for determining range (e.g. time-of-flight, triangulation, modulation, etc.), the target state determination component  650  may determine one or more components of the target&#39;s translational motion (e.g. velocities along x, y, and z axis). In further embodiments, the target state determination component  650  may be configured to determine the range and one or more components of the customary six degrees-of-freedom of motion of the target (or object), including translational motion components and rotational motion components if desired. The target state determination component  650  may then provide such target state information to the control system  116 . 
     The control system  116  is configured to receive information from the laser motion determination component  620  and the target state determination component  650 , to assess whether the target has reached the maximum permitted exposure (MPE) level for the particular operating conditions, and if necessary, to transmit appropriate control signals to one or more of the other components of the laser system  110  (e.g. laser source  112 , beam directing assembly  114 , etc.) to adjust one or more operating conditions of the laser system  610  to ensure that the MPE level is not exceeded. 
     For example, in some embodiments, the laser motion determination component  620  may provide information to the control system  116  regarding the translational and rotational motion of the laser system  610 , while the target state determination component  650  provides information to the control system  116  regarding the range and translational motion (but not rotational motion) of the targets and objects within the field of view of the laser system  610 . In other embodiments, the laser motion determination component  620  provides information to the control system  116  regarding the translational and rotational motion of the laser system  610 , while the target state determination component  650  provides only ranging (or distance) information to the control system  116  regarding the targets and objects within the field of view. In still other embodiments, one of the components  620 ,  650  may be omitted entirely, and the control system  112  may receive information from the remaining one of the components  620 ,  650 . Of course, in still other embodiments, both of the components  620 ,  650  may provide any desired combination of information regarding the six degrees-of-freedom of the laser system  610  and the range and motion of the targets and objects within the field of view. The control system  112  is configured with suitable control logic (e.g. software, hardware, firmware, or combinations thereof) to use the information received from the one or more components  620 ,  650 , and to provide appropriate control signals to adjust one or more operating conditions of the laser system  610  (e.g. intensity, output power, divergence, attenuation, wavelength, complete shutdown, etc.) as desired. For example, the control system  112  may be configured to adjust the laser system  610  to ensure that the MPE level is not exceeded. Alternately, the control system  112  may be configured to adjust the laser system  610  to react a certain way for certain operating scenarios. For example, in a particular embodiment, if a target is approaching the laser system, an adjustment of the laser system may be made (e.g. the modulation rate or power level could be automatically increased) to warn the target, or to perform any other desired function. 
       FIG. 11  is a table  700  of some of the potential operating conditions that may be encountered by embodiments of laser systems in accordance with the present disclosure, including the laser system  610  of  FIG. 10 . For example, as shown in the column entitled “Laser &amp; Target Relative Motion,” embodiments of the present disclosure may encounter one or more of the following possible operating conditions: stationary laser system and target, radial motion (moving toward or away along laser beam axis); perpendicular motion (moving across laser beam axis), angular motion (laser pitch or yaw sweeping beam across target), combinations of the above conditions, and tracking aircraft. 
     Under the column entitled “Scenario,” the table  700  provides a few representative scenarios that may be encountered for each category of “Laser &amp; Target Relative Motion.” For example, for the “Stationary” category, a possible scenario includes a human looking at the laser. For the “Radial Motion” category, the table  700  shows possible scenarios including a human walking into the laser beam, a human running into the laser beam, a car approaching the laser at highway speeds, and a moving convoy approaching an oncoming vehicle. Similarly, for the “Perpendicular Motion” category, the possible scenarios include an LRF (Laser Range Finder) update threshold, a human walking through (or across) the laser beam, a human running through (or across) the laser beam, a car crossing a checkpoint at highway speeds, and a moving convoy crossing an oncoming vehicle. For the “Angular Motion” category, the table  700  shows possible scenarios including an LRF update threshold, walking beam into target, and “horseplay” (e.g. erratic movement of the laser beam by an operator for amusement). 
     For each combination of the above-listed categories and scenarios, the table  700  also provides exemplary values for relative velocity (translational and rotational), effective NOHD, and exposure time. Of course, it will be appreciated that the table  700  is merely representative of some possible operating conditions, and is not exhaustive of all possible operating conditions that may be experienced by embodiments of methods and systems in accordance with the present disclosure. 
       FIG. 12  is a process  750  for operating a laser system in accordance with another embodiment of the present disclosure. In this embodiment, the process  750  includes operating a laser system to provide a laser beam toward a target at  752 . At  754 , a control system receives information from one or more of a laser motion determination component and a target/object state determination component. As described above, in various alternate embodiments, the control system may receive information from either the laser motion determination component or the target/object state determination component, or both, and one or both of the components may provide any desired combination of information regarding the six degrees-of-freedom and ranges of the laser system and the targets/objects within the field of view. In some embodiments, the field of view is coincident with the laser beam. Alternately, the field of view may be larger than the laser beam. The motion and state determination components may be operated simultaneously or sequentially with each other and with the laser system. In some embodiments, the target state determination component provides its own sensing signals, while in other embodiments, the target state determination component uses reflected laser light generated by the laser system, or any other source of state determination signals (e.g. GPS signals, contact sensors, images, etc.). 
     At  756 , the process  750  analyzes the information received at  754  and determines whether the maximum permissible exposure has been exceeded for any of the one or more targets and objects within the field of view. For example, with reference to the table  700  shown in  FIG. 11 , some of the objects and targets within the field of view may be stationary with respect to the laser system, while others may be moving radially, perpendicularly, or angularly with respect to the laser system. If it is determined that the MPE has not been exceeded (at  756 ), then the process  750  returns to  752  and continues performing the above-noted activities indefinitely ( 752  through  756 ). 
     On the other hand, if the MPE has been exceeded (at  756 ), then the process  750  adjusts one or more of the laser operating conditions at  758 . For example, in some embodiments, a control system may controllably adjust one or more characteristics of the laser system (e.g. a laser source, a beam directing assembly, etc.) in order to adjust one or more characteristics of the laser beam (e.g. intensity, output power, divergence, attenuation, wavelength, complete shutdown, etc.). 
     After performing the adjustment at  758 , the process  750  may optionally determine whether a limit condition has been reached at  760 . For example, the process  750  may determine whether some type of lower (or minimum) operating limit has been reached on a laser operating condition (e.g. output power, divergence angle, etc.) so that continued operation of the laser is no longer practical or suitable for its intended purpose. If the determination at  760  is affirmative, the process  750  may proceed to a shutdown at  762  or any other suitable activity. Alternately, if no limit condition has been reached (at  760 ), then the process  750  may return to  752 , and may continue performing the above-described actions ( 752  through  760 ) indefinitely. 
     Embodiments of systems and methods having capabilities to determine the state and/or motion of the laser system and/or the target (or both) may provide significant advantages. Because such embodiments are able to determine the translational and rotational motions of the laser system and target, as well as range to the target, such embodiments may be better able to perform the desired functionality over a broader range of operating conditions. For example, such embodiments may be better able to provide the desired auto-control capabilities when one or more of the objects and targets within the field of view are moving radially, perpendicularly, or angularly with respect to the laser system. Such embodiments may even provide improved capability to perform the desired functionality during off-design conditions such as horseplay by the operator, or bumping, dropping, or other accidental movement of the laser system. Thus, embodiments of systems and methods in accordance with the present disclosure may advantageously enhance the safety of laser operations in a variety of conditions and circumstances where conventional safety methods and protocols are impractical or impossible to implement. 
     The detailed descriptions of the above embodiments are not exhaustive descriptions of all embodiments contemplated by the inventors to be within the scope of the invention. Indeed, persons skilled in the art will recognize that certain elements of the above-described embodiments may variously be combined or eliminated to create further embodiments, and such further embodiments fall within the scope and teachings of the invention. It will also be apparent to those of ordinary skill in the art that the above-described embodiments may be combined in whole or in part to create additional embodiments within the scope and teachings of the present disclosure. Accordingly, the scope of the invention should be determined from the following claims.