Patent Publication Number: US-9429398-B2

Title: Optical tracking for controlling pyrotechnic show elements

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/001,551, filed May 21, 2014, which is incorporated herein by reference in its entirety for all purposes. 
    
    
     BACKGROUND 
     The present disclosure relates generally to the field of tracking systems and, more particularly, to methods and equipment used to enable tracking of elements in a variety of contexts through a dynamic signal to noise ratio tracking system. 
     Tracking systems have been widely used to track motion, position, orientation, and distance, among other aspects, of objects in a wide variety of contexts. Such existing tracking systems generally include an emitter that emits electromagnetic energy and a detector configured to detect the electromagnetic energy, sometimes after it has been reflected off an object. It is now recognized that traditional tracking systems have certain disadvantages and that improved tracking systems are desired for use in a variety of contexts, including amusement park attractions, workplace monitoring, sports, fireworks displays, factory floor management, robotics, security systems, parking, and transportation, among others. 
     BRIEF DESCRIPTION 
     In accordance with an embodiment of the present disclosure, an amusement park pyrotechnic show tracking and control system includes an emitter configured to emit electromagnetic radiation into a pyrotechnic show area; ordinance having pyrotechnic show elements encased within an enclosure, wherein the ordinance has a retro-reflective marker positioned on the enclosure and configured to retro-reflect the electromagnetic radiation emitted by the emitter; a detection camera having a view of the pyrotechnic show area and configured to detect retro-reflection of the electromagnetic radiation from the retro-reflective marker; and a control system communicatively coupled to the detection camera and having processing circuitry configured to: monitor the retro-reflected electromagnetic radiation from the retro-reflective marker to track movement of the retro-reflective marker in space and time; and correlate movement of the retro-reflective marker to movement of the ordinance to track the movement of the ordinance through space and time. 
     In accordance with another embodiment of the present disclosure, a method of tracking and controlling a pyrotechnic show in an amusement park includes: directing electromagnetic radiation into a pyrotechnic show area using an emitter; detecting wavelengths of electromagnetic radiation retro-reflected from within the pyrotechnic show area using a detection camera; and tracking, in space and time, a movement of an ordinance having pyrotechnic show elements based on changes in the retro-reflected electromagnetic radiation from within the pyrotechnic show area using a control system communicatively coupled to the detection camera. 
     In accordance with a further embodiment of the present disclosure, an amusement park pyrotechnic show system includes: ordinance having pyrotechnic show elements encased within an enclosure, wherein the ordinance includes a retro-reflective marker positioned on the enclosure and configured to retro-reflect electromagnetic radiation outside of the visible range of the electromagnetic spectrum. The ordinance also includes a detonation charge and an electronic fuse mechanism having an internal fuse. The detonation charge is configured to detonate the ordinance and trigger the pyrotechnic show elements in response to an applied stimulus from the internal fuse; and wherein the electronic fuse mechanism has communication circuitry configured to communicate with a remote detonation system and to initiate application of the stimulus to the detonation charge by the internal fuse in response to a control signal from the remote detonation system. 
     In accordance with a further embodiment of the present disclosure, a method of atracking and controlling a pyrotechnic show effect includes: flooding a ride vehicle path of an amusement park attraction with electromagnetic radiation using an emission subsystem having one or more emitters; detecting wavelengths of electromagnetic radiation retro-reflected from within the ride vehicle path using a detection subsystem having one or more detectors; tracking, in space and time, a movement and a location of a ride vehicle on the ride vehicle path based on changes in the retro-reflected electromagnetic radiation with a control system having processing circuitry communicatively coupled to the detection subsystem; triggering a pyrotechnic show effect when a tracked location of the ride vehicle has a predetermined relationship relative to the pyrotechnic show effect using a pyrotechnic show effect device coupled to the control system; detecting electromagnetic radiation emitted by the pyrotechnic show effect using the detection subsystem; comparing the electromagnetic radiation emitted by the pyrotechnic show effect to a reference signature of the electromagnetic radiation emitted by the pyrotechnic show effect stored in a memory of the control system; and adjusting an operating parameter of the pyrotechnic show effect device based on the comparison using the control system. 
    
    
     
       DRAWINGS 
       These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  is a schematic diagram of a tracking system utilizing a dynamic signal to noise ratio device to track objects, in accordance with an embodiment of the present disclosure; 
         FIG. 2  is a schematic diagram of another tracking system utilizing a dynamic signal to noise ratio device to track objects, in accordance with an embodiment of the present disclosure; 
         FIG. 3  is a schematic view of the tracking system of  FIG. 1  tracking a retro-reflective marker on a person, in accordance with an embodiment of the present disclosure; 
         FIG. 4  is a schematic representation of an analysis performed by the tracking system of  FIG. 1  in which position and movement of a person or object is tracked in space and time, in accordance with an embodiment of the present disclosure; 
         FIG. 5  is an overhead view of a room with a grid pattern of retro-reflective markers for tracking a position of people in the room via the tracking system of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 6  is an elevational view of the tracking system of  FIG. 1  tracking a person without tracking retro-reflective marker movement and without tracking retro-reflective marker occlusion, in accordance with an embodiment of the present disclosure; 
         FIG. 7  is an elevational view of a room with a grid pattern of retro-reflective markers disposed on a wall and a floor of the room for tracking a position of people and objects in the room via the tracking system of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 8  illustrates cross-sections of retro-reflective markers having different coatings to enable different wavelengths of electromagnetic radiation to be reflected back toward the detector of the tracking system of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIGS. 9A-9C  depict the manner in which an object may be tracked in three spatial dimensions by the tracking system of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 10  is a flow diagram illustrating an embodiment of a method of tracking reflection and controlling amusement park elements based on the tracked reflection using the tracking system of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 11  is a perspective view of the tracking system of  FIG. 1  being used in surveying equipment to determine changes in elevation or coloration of structures, in accordance with an embodiment of the present disclosure; 
         FIG. 12  is a schematic representation of the manner in which the tracking system of  FIG. 1  monitors the change in a surface condition of a structure having a retro-reflective marker positioned under the surface, in accordance with an embodiment of the present disclosure; 
         FIG. 13  is a perspective view of the tracking system of  FIG. 1  being used to survey an amusement park ride, including support structures and a track, to determine changes in structural elevation of the ride, in accordance with an embodiment of the present disclosure; 
         FIG. 14  is a perspective view of the tracking system of  FIG. 1  used to monitor an amusement park ride vehicle and a flame effect, in accordance with an embodiment of the present disclosure; 
         FIG. 15  is a cross-sectional side view of a flame-producing device monitored and controlled by the tracking system of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 16  is a perspective view of the tracking system of  FIG. 1  being used to monitor a height of ordinances in a firework show, in accordance with an embodiment of the present disclosure; 
         FIG. 17  is a cross-sectional side view of an ordinance having an electronic detonator and a retro-reflective marker attached to its outer casing to enable the ordinance to be tracked by the tracking system of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 18  is a perspective view of a firework show using robotically-actuated cannons that are controlled by the tracking system of  FIG. 1 , in accordance with an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Generally, tracking systems may use a wide variety of inputs obtained from a surrounding environment to track certain objects. The source of the inputs may depend, for instance, on the type of tracking being performed and the capabilities of the tracking system. For example, tracking systems may use sensors disposed in an environment to actively generate outputs received by a main controller. The controller may then process the generated outputs to determine certain information used for tracking One example of such tracking may include tracking the motion of an object to which a sensor is fixed. Such a system might also utilize one or more devices used to bathe an area in electromagnetic radiation, a magnetic field, or the like, where the electromagnetic radiation or magnetic field is used as a reference against which the sensor&#39;s output is compared by the controller. As may be appreciated, such active systems, if implemented to track a large number of objects or even people, could be quite expensive to employ and processor-intensive for the main controller of the tracking system. 
     Other tracking systems, such as certain passive tracking systems, may perform tracking without providing an illumination source or the like. For instance, certain tracking systems may use one or more cameras to obtain outlines or rough skeletal estimates of objects, people, and so forth. However, in situations where background illumination may be intense, such as outside on a hot and sunny day, the accuracy of such a system may be reduced due to varying degrees of noise received by detectors of the passive tracking system. 
     With the foregoing in mind, it is now recognized that traditional tracking systems have certain disadvantages and that improved tracking systems are desired for use in a variety of contexts, including amusement park attractions, workplace monitoring, sports, and security systems, among others. For instance, it is presently recognized that improved tracking systems may be utilized to enhance operations in a variety of amusement park settings and other entertainment attractions. 
     In accordance with one aspect of the present disclosure, a dynamic signal to noise ratio tracking system uses emitted electromagnetic radiation and, in some embodiments, retro-reflection, to enable detection of markers and/or objects within the field of view of the tracking system. The disclosed tracking system may include an emitter configured to emit electromagnetic radiation in a field of view, a sensing device configured to detect the electromagnetic radiation retro-reflected back from objects within the field of view, and a controller configured to perform various processing and analysis routines including interpreting signals from the sensing device and controlling automated equipment based on the detected locations of the objects or markers. The disclosed tracking system may also be configured to track several different objects at the same time (using the same emission and detection features). In some embodiments, the tracking system tracks a location of retro-reflective markers placed on the objects to estimate a location of the objects. As used herein, retro-reflective markers are reflective markers designed to retro-reflect electromagnetic radiation approximately back in the direction from which the electromagnetic radiation was emitted. More specifically, retro-reflective markers used in accordance with the present disclosure, when illuminated, reflect electromagnetic radiation back toward the source of emission in a narrow cone. In contrast, certain other reflective materials, such as shiny materials, may undergo diffuse reflection where electromagnetic radiation is reflected in many directions. Further still, mirrors, which also reflect electromagnetic radiation, do not typically undergo retro-reflection. Rather, mirrors undergo specular reflection, where an angle of light incident onto the mirror is reflected at an equal but opposite angle (away from the emission source). 
     Retro-reflective materials used in accordance with the embodiments set forth below can be readily obtained from a number of commercial sources. One example includes retro-reflective tape, which may be fitted to a number of different objects (e.g., environmental features, clothing items, toys). Due to the manner in which retro-reflection occurs using such markers in combination with the detectors  16  used in accordance with the present disclosure, the retro-reflective markers cannot be washed out by the sun or even in the presence of other emitters that emit electromagnetic radiation in wavelengths that overlap with the wavelengths of interest. Accordingly, the disclosed tracking system may be more reliable, especially in an outdoor setting and in the presence of other electromagnetic emission sources, compared to existing optical tracking systems. 
     While the present disclosure is applicable to a number of different contexts, presently disclosed embodiments are directed to, among other things, various aspects relating to tracking changes to certain structures (e.g., building, support columns) within an amusement park, and, in some situations, controlling amusement park equipment (e.g., automated equipment) based on information obtained from such a dynamic signal to noise ratio tracking system. Indeed, it is presently recognized that by using the disclosed tracking systems, reliable and efficient amusement park operations may be carried out, even though there are a number of moving objects, guests, employees, sounds, lights, and so forth, in an amusement park, which could otherwise create high levels of noise for other tracking systems, especially other optical tracking systems that do not use retro-reflective markers in the manner disclosed herein. 
     In certain aspects of the present disclosure, a control system of the amusement park (e.g., a control system associated with a particular area of the amusement park, such as a ride) may use information obtained by the dynamic signal to noise ratio tracking system to monitor and evaluate information relating to people, machines, vehicles (e.g., guest vehicles, service vehicles), and similar features in the area to provide information that may be useful in the more efficient operation of amusement park operations. For example, the information may be used to determine whether certain automated processes may be triggered or otherwise allowed to proceed. The evaluated information pertaining to vehicles in the amusement park may include, for instance, a location, a movement, a size, or other information relating to automated machines, ride vehicles, and so forth, within certain areas of the amusement park. By way of non-limiting example, the information may be evaluated to track people and machines to provide enhanced interactivity between the people and the machines, to track and control unmanned aerial vehicles, to track and control ride vehicles and any show effects associated with the ride vehicle, and so forth. 
     Certain aspects of the present disclosure may be better understood with reference to  FIG. 1 , which generally illustrates the manner in which a dynamic signal to noise ratio tracking system  10  (hereinafter referred to as “tracking system  10 ”) may be integrated with amusement park equipment  12  in accordance with present embodiments. As illustrated, the tracking system  10  includes an emitter  14  (which may be all or a part of an emission subsystem having one or more emission devices and associated control circuitry) configured to emit one or more wavelengths of electromagnetic radiation (e.g., light such as infrared, ultraviolet, visible, or radio waves and so forth) in a general direction. The tracking system  10  also includes a detector  16  (which may be all or a part of a detection subsystem having one or more sensors, cameras, or the like, and associated control circuitry) configured to detect electromagnetic radiation reflected as a result of the emission, as described in further detail below. 
     To control operations of the emitter  14  and detector  16  (emission subsystem and detection subsystem) and perform various signal processing routines resulting from the emission, reflection, and detection process, the tracking system  10  also includes a control unit  18  communicatively coupled to the emitter  14  and detector  16 . Accordingly, the control unit  18  may include one or more processors  20  and one or more memory  22 , which may generally referred to herein as “processing circuitry.” By way of specific but non-limiting example, the one or more processors  20  may include one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), one or more general purpose processors, or any combination thereof. Additionally, the one or more memory  22  may include volatile memory, such as random access memory (RAM), and/or non-volatile memory, such as read-only memory (ROM), optical drives, hard disc drives, or solid-state drives. In some embodiments, the control unit  18  may form at least a portion of a control system configured to coordinate operations of various amusement park features, including the equipment  12 . As described below, such an integrated system may be referred to as an amusement park attraction and control system. 
     The tracking system  10  is specifically configured to detect a position of an illuminated component, such as a retro-reflective marker  24  having a properly correlated retro-reflective material relative to a grid, pattern, the emission source, stationary or moving environmental elements, or the like. In some embodiments, the tracking system  10  is designed to utilize the relative positioning to identify whether a correlation exists between one or more such illuminated components and a particular action to be performed by the amusement park equipment  12 , such as triggering of a show effect, dispatch of a ride vehicle, closure of a gate, synchronization of security cameras with movement, and so on. More generally, the action may include the control of machine movement, image formation or adaptation, and similar processes. 
     As illustrated, the retro-reflective marker  24  is positioned on an object  26 , which may correspond to any number of static or dynamic features. For instance, the object  26  may represent boundary features of an amusement park attraction, such as a floor, a wall, a gate, or the like, or may represent an item wearable by a guest, park employee, or similar object. Indeed, as set forth below, within an amusement park attraction area, many such retro-reflective markers  24  may be present, and the tracking system  10  may detect reflection from some or all of the markers  24 , and may perform various analyses based on this detection. 
     Referring now to the operation of the tracking system  10 , the emitter  14  operates to emit electromagnetic radiation, which is represented by an expanding electromagnetic radiation beam  28 electromagnetic radiation beam  28  for illustrative purposes, to selectively illuminate, bathe, or flood a detection area  30  in the electromagnetic radiation. Electromagnetic radiation beam  28  is intended to generally represent any form of electromagnetic radiation that may be used in accordance with present embodiments, such as forms of light (e.g., infrared, visible, UV) and/or other bands of the electromagnetic spectrum (e.g., radio waves and so forth). However, it is also presently recognized that, in certain embodiments, it may be desirable to use certain bands of the electromagnetic spectrum depending on various factors. For example, in one embodiment, it may be desirable to use forms of electromagnetic radiation that are not visible to the human eye or within an audible range of human hearing, so that the electromagnetic radiation used for tracking does not distract guests from their experience. Further, it is also presently recognized that certain forms of electromagnetic radiation, such as certain wavelengths of light (e.g., infrared) may be more desirable than others, depending on the particular setting (e.g., whether the setting is “dark,” or whether people are expected to cross the path of the beam). Again, the detection area  30  may correspond to all or a part of an amusement park attraction area, such as a stage show, a ride vehicle loading area, a waiting area outside of an entrance to a ride or show, and so forth. 
     The electromagnetic radiation beam  28 , in certain embodiments, may be representative of multiple light beams (beams of electromagnetic radiation) being emitted from different sources (all part of an emission subsystem). Further, in some embodiments the emitter  14  is configured to emit the electromagnetic radiation beam  28  at a frequency that has a correspondence to a material of the retro-reflective marker  24  (e.g., is able to be reflected by the retro-reflective elements of the marker  24 ). For instance, the retro-reflective marker  24  may include a coating of retro-reflective material disposed on a body of the object  26  or a solid piece of material coupled with the body of the object  26 . By way of more specific but non-limiting example, the retro-reflective material may include spherical and/or prismatic reflective elements that are incorporated into a reflective material to enable retro-reflection to occur. Again, in certain embodiments many such retro-reflective markers  24  may be present, and may be arranged in a particular pattern stored in the memory  22  to enable further processing, analysis, and control routines to be performed by the control unit  18  (e.g., control system). 
     The retro-reflective marker  24  may reflect a majority of the electromagnetic radiation (e.g., infrared, ultraviolet, visible wavelengths, or radio waves and so forth) incident from the electromagnetic radiation beam  28  back toward the detector  16  within a relatively well-defined cone having a central axis with substantially the same angle as the angle of incidence. This reflection facilitates identification of a location of the retro-reflective marker  24  by the system  10  and correlation thereof to various information stored in the memory  22  (e.g., patterns, possible locations). This location information (obtained based on the reflected electromagnetic radiation) may then be utilized by the control unit  18  to perform various analysis routines and/or control routines, for example to determine whether to cause triggering or other control of the amusement park equipment  12 . 
     Specifically, in operation, the detector  16  of the system  10  may function to detect the electromagnetic radiation beam  28  retro-reflected from the retro-reflective marker  24  and provide data associated with the detection to the control unit  18  via communication lines  31  for processing. The detector  16  may operate to specifically identify the marker  24  based on certain specified wavelengths of electromagnetic radiation emitted and reflected and, thus, avoid issues with false detections. For example, the detector  16  may be specifically configured to detect certain wavelengths of electromagnetic radiation (e.g., corresponding to those emitted by the emitter  14 ) through the use of physical electromagnetic radiation filters, signal filters, and the like. Further, the detector  16  may utilize a specific arrangement of optical detection features and electromagnetic radiation filters to capture substantially only retro-reflected electromagnetic radiation. 
     For example, the detector  16  may be configured to detect wavelengths of electromagnetic radiation retro-reflected by the retro-reflective markers  24  while filtering wavelengths of electromagnetic radiation not retro-reflected by the markers  24 , including those wavelengths of interest. Thus, the detector  16  may be configured to specifically detect (e.g., capture) retro-reflected electromagnetic radiation while not detecting (e.g., capturing) electromagnetic radiation that is not retro-reflected. In one embodiment, the detector  16  may utilize the directionality associated with retro-reflection to perform this selective filtering. Accordingly, while the detector  16  receives electromagnetic radiation from a variety of sources (including spuriously reflected electromagnetic radiation, as well as environmental electromagnetic radiation), the detector  16  is specifically configured to filter out all or substantially all spuriously reflected signals while retaining all or substantially all intended signals. Thus, the signal-to-noise ratio of signals actually processed by the detector  16  and control unit  18  is very high, regardless of the signal-to-noise ratio that exists for the electromagnetic bands of interest outside of the detector  16 . 
     For example, the detector  16  may receive retro-reflected electromagnetic radiation (e.g., from the retro-reflective markers  24 ) and ambient electromagnetic radiation from within an area (e.g., guest attraction area). The ambient electromagnetic radiation may be filtered, while the retro-reflected electromagnetic radiation, which is directional, may not be filtered (e.g., may bypass the filter). Thus, in certain embodiments, the “image” generated by the detector  16  may include a substantially dark (e.g., black or blank) background signal, with substantially only retro-reflected electromagnetic radiation producing contrast. 
     In accordance with certain embodiments, the retro-reflected electromagnetic radiation may include different wavelengths that are distinguishable from one another. In one embodiment, the filters of the detector  16  may have optical qualities and may be positioned within the detector such that the optical detection devices of the detector  16  substantially only receive electromagnetic wavelengths retro-reflected by the retro-reflective markers  24  (or other retro-reflective elements), as well as any desired background wavelengths (which may provide background or other landscape information). To produce signals from the received electromagnetic radiation, as an example, the detector  16  may be a camera having a plurality of electromagnetic radiation capturing features (e.g., charge-coupled devices (CCDs) and/or complementary metal oxide semiconductor (CMOS) sensors corresponding to pixels). In one example embodiment, the detector  16  may be an amp® high dynamic range (HDR) camera system available from Contrast Optical Design and Engineering, Inc. of Albuquerque, N. Mex. 
     Because retro-reflection by the retro-reflective markers  24  is such that a cone of reflected electromagnetic radiation is incident on the detector  16 , the control unit  18  may in turn correlate a center of the cone, where the reflected electromagnetic radiation is most intense, to a point source of the reflection. Based on this correlation, the control unit  18  may identify and track a location of this point source, or may identify and monitor a pattern of reflection by many such retro-reflective markers  24 . 
     For instance, once the control unit  18  receives the data from the detector  16 , the control unit  18  may employ known visual boundaries or an established orientation of the detector  16  to identify a location (e.g., coordinates) corresponding to the detected retro-reflective marker  24 . When multiple stationary retro-reflective markers  24  are present, the control unit  18  may store known positions (e.g., locations) of the retro-reflective markers  24  to enable reflection pattern monitoring. By monitoring a reflection pattern, the control unit  18  may identify blockage (occlusion) of certain retro-reflective markers  24  by various moving objects, guests, employees, and so forth. It should also be noted that the bases for these comparisons may be updated based on, for example, how long a particular retro-reflective marker  24  has been positioned and used in its location. For instance, the stored pattern of reflection associated with one of the markers  24  may be updated periodically during a calibration stage, which includes a time period during which no objects or people are expected to pass over the marker  24 . Such re-calibrations may be performed periodically so that a marker that has been employed for an extended period of time and has lost its retro-reflecting capability is not mistaken for a detected occlusion event. 
     In other embodiments, in addition to or in lieu of tracking one or more of the retro-reflective markers  24 , the tracking system  10  may be configured to detect and track various other objects located within the detection area  30 . Such objects  32  may include, among other things, ride vehicles, people (e.g., guests, employees), and other moving park equipment. For example, the detector  16  of the system  10  may function to detect the electromagnetic radiation beam  28  bouncing off of an object  32  (without retro-reflective markers  24 ) and provide data associated with this detection to the control unit  18 . That is, the detector  16  may detect the object  32  based entirely on diffuse or specular reflection of electromagnetic energy off the object  32 . In some embodiments, the object  32  may be coated with a particular coating that reflects the electromagnetic radiation beam  28  in a detectable and predetermined manner. Accordingly, once the control unit  18  receives the data from the detector  16 , the control unit  18  may determine that the coating associated with the object  32  reflected the electromagnetic radiation, and may also determine the source of the reflection to identify a location of the object  32 . 
     Whether the retro-reflective markers  24  are stationary or moving, the process of emitting the electromagnetic radiation beam  28 , sensing of the reflected electromagnetic radiation from the retro-reflective markers  24  (or objects  32  with no or essentially no retro-reflective material), and determining a location of the retro-reflective marker  24  or object  32  may be performed by the control unit  18  numerous times over a short period. This process may be performed at distinct intervals, where the process is initiated at predetermined time points, or may be performed substantially continuously, such that substantially immediately after the process is completed, it is re-initiated. In embodiments where the retro-reflective markers  24  are stationary and the control unit  18  performs retro-reflective pattern monitoring to identify marker blockage, the process may be performed at intervals to obtain a single retro-reflective pattern at each interval. This may be considered to represent a single frame having a reflection pattern corresponding to a pattern of blocked and unblocked retro-reflective markers  24 . 
     On the other hand, such procedures may essentially be performed continuously to facilitate identification of a path and/or trajectory through which the retro-reflective marker  24  has moved. The marker  24 , moving within the detection area  30 , would be detected over a particular timeframe or simply in continuous series. Here, the pattern of reflection would be generated and identified over a time period. 
     In accordance with the embodiments set forth above, the detector  16  and control unit  18  may operate on a variety of different timeframes depending on the tracking to be performed and the expected movement of the tracked object through space and time. As an example, the detector  16  and the control unit  18  may operate in conjunction to complete all logical processes (e.g., updating analysis and control signals, processing signals) in the time interval between the capture events of the detector  16 . Such processing speeds may enable substantially real-time tracking, monitoring, and control where applicable. By way of non-limiting example, the detector capture events may be between approximately 1/60 of a second and approximately 1/30 of a second, thus generating between 30 and 60 frames per second. The detector  16  and the control unit  18  may operate to receive, update, and process signals between the capture of each frame. However, any interval between capture events may be utilized in accordance with certain embodiments. 
     Once a particular pattern of retro-reflection has been detected, a determination may be made by the control unit  18  as to whether the pattern correlates to a stored pattern identified by the control unit  18  and corresponding to a particular action to be performed by the amusement park equipment  12 . For example, the control unit  18  may perform a comparison of a position, path, or trajectory of the retro-reflective marker  24  with stored positions, paths, or trajectories to determine an appropriate control action for the equipment  12 . Additionally or alternatively, as described in further detail below, the control unit  18  may determine whether a particular pattern obtained at a particular time point correlates to a stored pattern associated with a particular action to be performed by the amusement park equipment  12 . Further still, the control unit  18  may determine whether a set of particular patterns obtained at particular time points correlate to a stored pattern change associated with a particular action to be performed by the amusement park equipment  12 . 
     While the control unit  18  may cause certain actions to be automatically performed within the amusement park in the manner set forth above, it should be noted that similar analyses to those mentioned above may also be applied to the prevention of certain actions (e.g., where the park equipment  12  blocks action or is blocked from performing an action). For example, in situations where a ride vehicle can be automatically dispatched, the control unit  18 , based upon tracking changes in the retro-reflective markers  24 , may halt automatic dispatching, or may even prevent dispatching by a ride operator until additional measures are taken (e.g., additional confirmations that the ride vehicle is cleared for departure). This type of control may be applied to other amusement park equipment, as well. For example, flame effects, fireworks, or similar show effects may be blocked from being triggered, may be stopped, or may be reduced in intensity, due to intervention by the control unit  18  as a result of certain pattern determinations as described herein. 
     Having generally described the configuration of the system  10 , it should be noted that the arrangement of the emitter  14 , detector  16 , control unit  18 , and other features may vary based on application-specific considerations and the manner in which the control unit  18  performs evaluations based on electromagnetic radiation from the retro-reflective markers  24 . In the embodiment of the tracking system  10  illustrated in  FIG. 1 , the emitter  14  and the sensor or detector  16  are integral features such that a plane of operation associated with the detector  16  is essentially overlapping with a plane of operation associated with the emitter  14 . That is, the detector  16  is located in substantially the same position as the emitter  14 , which may be desirable due to the retro-reflectivity of the markers  24 . However, the present disclosure is not necessarily limited to this configuration. For instance, as noted above, retro-reflection may be associated with a cone of reflection, where the highest intensity is in the middle of the reflected cone. Accordingly, the detector  16  may be positioned within an area where the reflected cone of the retro-reflective markers is less intense than its center, but may still be detected by the detector  16 . 
     By way of non-limiting example, in some embodiments, the emitter  14  and the detector  16  may be concentric. However, the detector  16  (e.g., an infrared camera) may be positioned in a different location with respect to the emitter  14 , which may include an infrared light bulb, one or more diode emitters, or similar source. As illustrated in  FIG. 2 , the emitter  14  and detector  16  are separate and are positioned at different locations on an environmental feature  40  of an amusement attraction area (e.g., a wall or ceiling). Specifically, the emitter  14  of  FIG. 2  is positioned outside of a window  42  of a storefront containing other components of the system  10 . The detector  16  of  FIG. 2  is positioned away from the emitter  14 , but is still oriented to detect electromagnetic radiation reflected from the retro-reflective marker  24  and originating from the emitter  14 . 
     For illustrative purposes, arrows  44 ,  46  represent a light beam (a beam of electromagnetic radiation) being emitted from the emitter  14  (arrow  44 ) into the detection area  30 , retro-reflected by the retro-reflective marker  24  on the object  26  (arrow  46 ), and detected by the detector  16 . The light beam represented by the arrow  44  is merely one of numerous electromagnetic radiation emissions (light beams) that flood or otherwise selectively illuminate the detection area  30  from the emitter  14 . It should be noted that still other embodiments may utilize different arrangements of components of the system  10  and implementations in different environments in accordance with the present disclosure. 
     Having now discussed the general operation of the tracking system  10  to detect a position of retro-reflective markers  24  and/or objects  32 , as illustrated in  FIG. 1 , certain applications of the tracking system  10  will be described in further detail below. For example, it may be desirable to track the locations of people within a particular area through the use of the disclosed tracking systems. This may be useful, for example, for controlling lines in a ride vehicle loading area, controlling access to different areas, determining appropriate instances when show effects can be triggered, determining appropriate instances when certain automated machinery can be moved, and may also be useful for assisting a live show performance (e.g., blocking actors on a stage). That is, during performances, actors are supposed to be standing at particular positions on the stage at certain times. To ensure that the actors are hitting their appropriate positions at the right time, the tracking system  10  may be installed above the stage and used to track the positions and/or motion of all the actors on the stage. Feedback from the tracking system  10  may be utilized to evaluate how well the actors are hitting the desired spots on the stage. 
     In addition to blocking on a stage, the tracking system  10  may be used in contexts that involve tracking and/or evaluating shoppers in a store or other commercial setting. That is, a store may be outfitted with the disclosed tracking systems  10  in order to determine where guests are spending time within the store. Instead of triggering a show effect, such tracking systems  10  may be used to monitor the flow of people within the store and control the availability of certain items as a result, control the flow of movement of people, etc. For instance, information collected via the disclosed tracking systems  10  may be used to identify and evaluate which setups or displays within the store are most attractive, to determine what items for sale are the most popular, or to determine which areas of the store, if any, are too crowded. This information may be analyzed and used to improve the store layout, product development, and crowd management, among other things. 
     It should be noted that other applications may exist for tracking positions of people, objects, machines, etc. within an area other than those described above. Presently disclosed tracking systems  10  may be configured to identify and/or track the position and movement of people and/or objects within the detection area  30 . The tracking system  10  may accomplish this tracking in several different ways, which were introduced above and are explained in further detail below. It should be noted that the tracking system  10  is configured to detect a position of one or more people, one or more objects  32 , or a combination of different features, at the same time in the same detection area  30  using the single emitter  14 , detector  16 , and control unit  18 . However, the use of multiple such emitters  14 , detectors  16 , and control units  18  is also within the scope of the present disclosure. Accordingly, there may be one or more of the emitters  14  and one or more of the detectors  16  in the detection area  30 . Considerations such as the type of tracking to be performed, the desired range of tracking, for redundancy, and so forth, may at least partially determine whether multiple or a single emitter and/or detector are utilized. 
     For instance, as noted above, the tracking system  10  may generally be configured to track a target moving in space and in time (e.g., within the detection area  30  over time). When a single detection device (e.g., detector  16 ) is utilized, the tracking system  10  may monitor retro-reflected electromagnetic radiation from a defined orientation to track a person, object, etc. Because the detector  16  has only one perspective, such detection and tracking may, in some embodiments, be limited to performing tracking in only one plane of movement (e.g., the tracking is in two spatial dimensions). Such tracking may be utilized, as an example, in situations where the tracked target has a relatively low number of degrees of freedom, such as when movement is restricted to a constrained path (e.g., a track). In one such embodiment, the target has a determined vector orientation. 
     On the other hand, when multiple detection devices are utilized (e.g., two or more of the detectors  16 ) to track a target in both space and time, the tracking system  10  may monitor retro-reflected electromagnetic radiation from multiple orientations. Using these multiple vantage points, the tracking system  10  may be able to track targets having multiple degrees of freedom. In other words, the use of multiple detectors may provide both vector orientation and range for the tracked target. This type of tracking may be particularly useful in situations where it may be desirable to allow the tracked target to have unrestricted movement in space and time. 
     Multiple detectors may also be desirable for redundancy in the tracking. For example, multiple detection devices applied to scenarios where movement of the target is restricted, or not, may enhance the reliability of the tracking performed by the tracking system  10 . The use of redundant detectors  16  may also enhance tracking accuracy, and may help prevent geometric occlusion of the target by complex geometric surfaces, such as winding pathways, hills, folded clothing, opening doors, and so on. 
     In accordance with one aspect of the present disclosure, the tracking system  10  may track relative positions of multiple targets (e.g., people, objects, machines) positioned within the detection area  30  through the use of the retro-reflective markers  24 . As illustrated in  FIG. 3 , the retro-reflective markers  24  may be disposed on a person  70 . Additionally or alternatively, the marker  24  may be positioned on a machine or other object (e.g., object  26 ). Accordingly, the techniques disclosed herein for tracking movement of the person  70  in space and time may also be applied to movement of an object in the amusement park, either in addition to the person  70  or as an alternative to the person  70 . In such embodiments, the marker  24  may be positioned on an outside of the object  26  (e.g., a housing), as shown in  FIG. 1 . 
     In the illustrated embodiment of  FIG. 3 , the retro-reflective marker  24  is disposed on the outside of the person&#39;s clothing. For instance, the retro-reflective marker  24  may be applied as a strip of retro-reflective tape applied to an armband, headband, shirt, personal identification feature, or other article. Additionally or alternatively, the retro-reflective marker  24  may, in some embodiments, be sewn into clothing or applied to the clothing as a coating. The retro-reflective marker  24  may be disposed on the clothing of the person  70  in a position that is accessible to the electromagnetic radiation beam  28  being emitted from the emitter  14 . As the person  70  walks about the detection area  30  (in the case of the object  32 , the object  32  may move through the area  30 ), the electromagnetic radiation beam  28  reflects off the retro-reflective marker  24  and back to the detector  16 . The detector  16  communicates with the control unit  18  by sending a signal  72  to the processor  20 , this signal  72  being indicative of the reflected electromagnetic radiation detected via the detector  16 . The tracking system  10  may interpret this signal  72  to track the position or path of the person  70  (or object  32 ) moving about a designated area (i.e., track the person or object in space and time). Again, depending on the number of detectors  16  utilized, the control unit  18  may determine vector magnitude, orientation, and sense of the person and/or object&#39;s movement based on the retro-reflected electromagnetic radiation received. 
     The tracking of the person  70  (which may also be representative of a moving object) is illustrated schematically in  FIG. 4 . More specifically,  FIG. 4  illustrates a series  80  of frames  82  captured by the detector  16  (e.g., camera) over a period of time. As noted above, a plurality of such frames (e.g., between 30 and 60) may be generated every second in certain embodiments. It should be noted that  FIG. 4  may not be an actual representation of outputs produced by the tracking system  10 , but is described herein to facilitate an understanding of the tracking and monitoring performed by the control unit  18 . The frames  82  each represent the detection area  30 , and the position of the retro-reflective marker  24  within the area  30 . Alternatively, the frames  82  may instead represent marker blockage within the area  30 , for example where a grid of markers  24  are occluded by an object or person. 
     As shown, a first frame  82 A includes a first instance of the retro-reflective marker, designated as  24 A, having a first position. As the series  80  progresses in time, a second frame  82 B includes a second instance of the retro-reflective marker  24 B, which is displaced relative to the first instance, and so on (thereby producing third and fourth instances of the retro-reflective marker  24 C and  24 D). After a certain period of time, the control unit  18  has generated the series  80 , where the operation of generating the series  80  is generally represented by arrow  84 . 
     The series  80  may be evaluated by the control unit  18  in a number of different ways. In accordance with the illustrated embodiment, the control unit  18  may evaluate movement of the person  70  or object  32  by evaluating the positions of the marker  24  (or blockage of certain markers) over time. For example, the control unit  18  may obtain vector orientation, range, and sense, relating to the movement of the tracked target depending on the number of detectors  16  utilized to perform the tracking In this way, the control unit  18  may be considered to evaluate a composite frame  86  representative of the movement of the tracked retro-reflective marker  24  (or tracked blockage of markers  24 ) over time within the detection area  30 . Thus, the composite frame  86  includes the various instances of the retro-reflective marker  24  (including  24 A,  24 B,  24 C,  24 D), which may be analyzed to determine the overall movement of the marker  24  (and, therefore, the person  70  and/or object  26 , whichever the case may be). 
     As also illustrated in  FIG. 4 , this monitoring may be performed relative to certain environmental elements  88 , which may be fixed within the detection area  30  and/or may be associated with reflective materials. The control unit  18  may perform operations not only based on the detected positions of the marker  24 , but also based on extrapolated movement (e.g., a projected path of the retro-reflective marker  24  through the detection area  30  or projected positions of marker grid occlusion) in relation to the environmental elements  88 . 
     Another method for tracking one or more people  70  or objects  32  in an area is illustrated schematically in  FIG. 5 . Specifically,  FIG. 5  represents an overhead view of a group of people  70  standing in the detection area  30 . Although not illustrated, the tracking system  10  may be present directly above this detection area  30  in order to detect positions of people  70  (and other objects) present within the detection area  30  (e.g., to obtain a plan view of the detection area  30 ). In the illustrated embodiment, the retro-reflective markers  24  are positioned in a grid pattern  90  on a floor  92  of the detection area  30  (e.g., as a coating, pieces of tape, or similar attachment method). The retro-reflective markers  24  may be arranged in any desired pattern (e.g., grid, diamond, lines, circles, solid coating, etc.), which may be a regular pattern (e.g., repeating) or a random pattern. 
     This grid pattern  90  may be stored in the memory  22 , and portions of the grid pattern  90  (e.g., individual markers  24 ) may be correlated to locations of certain environmental elements and amusement park features (e.g., the amusement park equipment  12 ). In this way, the position of each of the markers  24  relative to such elements may be known. Accordingly, when the markers  24  retro-reflect the electromagnetic radiation beam  28  to the detector  16 , the location of the markers  24  that are reflecting may be determined and/or monitored by the control unit  18 . 
     As illustrated, when the people  70  or objects  32  are positioned over one or more of the retro-reflective markers  24  on the floor  92 , the occluded markers cannot reflect the emitted electromagnetic radiation back to the detector  16  above the floor  92 . Indeed, in accordance with an embodiment, the grid pattern  90  may include retro-reflective markers  24  that are spaced apart by a distance that allows the people or objects positioned on the floor  92  to be detectable (e.g., blocking at least one of the retro-reflective markers  24 ). In other words, the distance between the markers  24  may be sufficiently small so that objects or people may be positioned over at least one of the retro-reflective markers  24 . 
     In operation, the detector  16  may function to detect the electromagnetic radiation beam  28  retro-reflected from the retro-reflective markers  24  that are not covered up by people or objects located in the detection area  30 . As discussed above, the detector  16  may then provide data associated with this detection to the control unit  18  for processing. The control unit  18  may perform a comparison of the detected electromagnetic radiation beam reflected off the uncovered retro-reflective markers  24  (e.g., a detected pattern) with stored positions of the completely uncovered grid pattern  90  (e.g., a stored pattern) and/or other known grid patterns resulting from blockage of certain markers  24 . Based on this comparison, the control unit  18  may determine which markers  24  are covered to then approximate locations of the people  70  or objects  32  within the plane of the floor  92 . Indeed, the use of a grid positioned on the floor  92  in conjunction with a single detector  16  may enable the tracking of movement in two dimensions. If higher order tracking is desired, additional grids and/or additional detectors  16  may be utilized. In certain embodiments, based on the locations of the people  70  or objects  32  in the detection area  30 , the control unit  18  may adjust the operation of the amusement park equipment  12 . 
     The process of emitting the electromagnetic radiation beam  28 , sensing of the reflected electromagnetic radiation from the uncovered retro-reflective markers  24  on the floor  92 , and determining a location of the people  70  may be performed by the control unit  18  numerous times over a short period in order to identify a series of locations of the people  70  moving about the floor  92  (to track motion of the group). Indeed, such procedures may essentially be performed continuously to facilitate identification of a path through which the people  70  have moved within the detection area  30  during a particular timeframe or simply in continuous series. Once the position or path one or more of the people  70  has been detected, the control unit  18  may further analyze the position or path to determine whether any actions should be performed by the equipment  12 . 
     As discussed in detail above with respect to  FIG. 1 , the control unit  18  may be configured to identify certain objects that are expected to cross the path of the electromagnetic radiation beam  28  within the detection area  30 , including objects that are not marked with retro-reflective material. For example, as illustrated in  FIG. 6 , some embodiments of the tracking system  10  may be configured such that the control unit  18  is able to identify the person  70  (which is also intended to be representative of the object  32 ) located in the detection area  30 , without the use of the retro-reflective markers  24 . That is, the control unit  18  may receive data indicative of the electromagnetic radiation reflected back from the detection area  30 , and the control unit  18  may compare a digital signature of the detected radiation to one or more possible data signatures stored in memory  22 . That is, if the signature of electromagnetic radiation reflected back to the detector  16  matches closely enough to the signature of a person  70  or known object  32 , then the control unit  18  may determine that the person  70  or object  32  is located in the detection area  30 . For example, the control unit  18  may identify “dark spots,” or regions where electromagnetic radiation was absorbed rather than reflected, within the detection area  30 . These areas may have a geometry that the control unit  18  may analyze (e.g., by comparing to shapes, sizes, or other features of stored objects or people) to identify a presence, location, size, shape, etc., of an object (e.g., the person  70 ). 
     As may be appreciated with reference to  FIGS. 1, 2, 3, and 6 , the tracking system  10  may be positioned in a variety of locations to obtain different views of the detection area  30 . Indeed, it is now recognized that different locations and combinations of locations of one or more of the tracking systems  10  (or one or more elements of the tracking system  10 , such as multiple detectors  16 ) may be desirable for obtaining certain types of information relating to the retro-reflective markers  24  and the blockage thereof. For instance, in  FIG. 1 , the tracking system  10 , and in particular the detector  16 , is positioned to obtain an elevational view of at least the object  26  fitted with the retro-reflective marker  24  and the object  32 . In  FIG. 2 , the detector  16  is positioned to obtain an overhead perspective view of the detection area  30 , which enables detection of retro-reflective markers  24  positioned on a variety of environmental elements, moving objects, or people. In the embodiments of  FIGS. 3 and 6 , the detector  16  may be positioned to obtain a plan view of the detection area  30 . 
     These different views may provide information that may be utilized by the control unit  18  for specific types of analyses and, in certain embodiments, control actions that may depend on the particular setting in which they are located. For example, in  FIG. 7 , the tracking system  10 , and particularly the emitter  14  and the detector  16 , are positioned to obtain a perspective view of the person  70  (or object  32 ) in the detection area  30 . The detection area  30  includes the floor  92 , but also includes a wall  93  on which the retro-reflective markers  24  are positioned to form the grid pattern  90 . Here, the person  70  is blocking a subset of markers  24  positioned on the wall  93 . The subset of markers  24  are unable to be illuminated by the emitter  14 , are unable to retro-reflect the electromagnetic radiation back to the detector  16 , or both, because the person  70  (also intended to represent an object) is positioned between the subset of markers  24  and the emitter  14  and/or detector  16 . 
     The grid pattern  90  on the wall  93  may provide information not necessarily available from a plan view as shown in  FIGS. 3 and 6 . For example, the blockage of the retro-reflective markers  24  enables the control unit  18  to determine a height of the person  70 , a profile of the person  70 , or, in embodiments where there the object  32  is present, a size of the object  32 , a profile of the object  32 , and so forth. Such determinations may be made by the control unit  18  to evaluate whether the person  70  meets a height requirement for a ride, to evaluate whether the person  70  is associated with one or more objects  32  (e.g., bags, strollers), and may also be used to track movement of the person  70  or object  32  through the detection area  30  with a greater degree of accuracy compared to the plan view set forth in  FIGS. 3 and 6 . That is, the control unit  18  is better able to tie movement identified by blockage of the markers  24  to a particular person  70  by determining the person&#39;s profile, height, etc. Similarly, the control unit  18  is better able to track the movement of the object  32  through the detection area  30  by identifying the geometry of the object  32 , and tying identified movement specifically to the object  32 . In certain embodiments, tracking the height or profile of the person  70  may be performed by the tracking system  10  to enable the control unit 18  to provide recommendations to the person  70  based on an analysis of the person&#39;s evaluated height, profile, etc. Similar determinations and recommendations may be provided for objects  32 , such as vehicles. For example, the control unit  18  may analyze a profile of guests at an entrance to a queue area for a ride. The control unit  18  may compare the overall size, height, etc., of the person  70  with ride specifications to warn individuals or provide a confirmation that they are able to ride the ride before spending time in the queue. Similarly, the control unit  18  may analyze the overall size, length, height, etc., of a vehicle to provide parking recommendations based on available space. Additionally or alternatively, the control unit  18  may analyze the overall size, profile, etc., of an automated piece equipment before allowing the equipment to perform a particular task (e.g., movement through a crowd of people). 
     The pattern  90  may also be positioned on both the wall  93  and the floor  92 . Accordingly, the tracking system  10  may be able to receive retro-reflected electromagnetic radiation from markers  24  on the wall  93  and the floor  92 , thereby enabling detection of marker blockage and monitoring of movement in three dimensions. Specifically, the wall  93  may provide information in a height direction  94 , while the floor  92  may provide information in a depth direction  96 . Information from both the height direction  94  and the depth direction  96  may be correlated to one another using information from a width direction  98 , which is available from both the plan and elevational views. 
     Indeed, it is now recognized that if two objects  32  or people  70  overlap in the width direction  98 , they may be at least partially resolved from one another using information obtained from the depth direction  96 . Further, it is also now recognized that the use of multiple emitters  14  and detectors  16  in different positions (e.g., different positions in the width direction  98 ) may enable resolution of height and profile information when certain information may be lost or not easily resolved when only one emitter  14  and detector  16  are present. More specifically, using only one emitter  14  and detector  16  may result in a loss of certain information if there is overlap between objects  32  or people  70  in the width direction  98  (or, more generally, overlap in a direction between the markers  24  on the wall  93  and the detector  16 ). However, embodiments using multiple (e.g., at least two) detectors  16  and/or emitters  14  may cause distinct retro-reflective patterns to be produced by the markers  24  and observed from the detectors  16  and/or emitters  14  positioned at different perspectives. Indeed, because the markers  24  are retro-reflective, they will retro-reflect electromagnetic radiation back toward the electromagnetic radiation source, even when multiple sources emit at substantially the same time. Thus, electromagnetic radiation emitted from a first of the emitters  14  from a first perspective will be retro-reflected back toward the first of the emitters  14  by the markers  24 , while electromagnetic radiation emitted from a second of the emitters  14  at a second perspective will be retro-reflected back toward the second of the emitters  14  by the markers  24 , which enables multiple sets of tracking information to be produced and monitored by the control unit  18 . 
     It is also now recognized that the retro-reflective markers  24  on the wall  93  and the floor  92  may be the same, or different. Indeed, the tracking system  10  may be configured to determine which electromagnetic radiation was reflected from the wall  93  versus which electromagnetic radiation was reflected from the floor  92  using a directionality of the retro-reflected electromagnetic radiation from the wall  93  and the floor  92 . In other embodiments, different materials may be used for the markers  24  so that, for example, different wavelengths of electromagnetic radiation may be reflected back toward the emitter  14  and detector  16  by the different materials. As an example, the retro-reflective markers  24  on the floor  92  and the wall  93  may have the same retro-reflective elements, but different layers that act to filter or otherwise absorb portions of the emitted electromagnetic radiation so that electromagnetic radiation reflected by the retro-reflective markers  24  on the floor  92  and wall  93  have characteristic and different wavelengths. Because the different wavelengths would be retro-reflected, the detector  16  may detect these wavelengths and separate them from ambient electromagnetic radiation, which is filtered by filter elements within the detector  16 . 
     To help illustrate,  FIG. 8  depicts expanded cross-sectional views of example retro-reflective markers  24  disposed on the floor  92  and the wall  93  within the detection area  30 . The markers  24  on the floor  92  and the wall  93  each include a reflective layer  96  and a retro-reflective material layer  98 , which may be the same or different for the floor  92  and wall  93 . In the illustrated embodiment, they are the same. During operation, electromagnetic radiation emitted by the emitter  14  may traverse a transmissive coating  99  before striking the retro-reflective material layer  98 . Accordingly, the transmissive coating  99  may be used to adjust the wavelengths of electromagnetic radiation that are retro-reflected by the markers. In  FIG. 8 , the markers  24  on the floor  92  include a first transmissive coating  99 A, which is different than a second transmissive coating  99 B in the markers  24  on the wall  93 . In certain embodiments, different optical properties between the first and second transmissive coatings  99 A,  99 B may cause a different bandwidth of electromagnetic radiation to be reflected by the markers  24  on the floor  92  and the markers  24  on the wall  93 . While presented in the context of being disposed on the floor  92  and the wall  93 , it should be noted that markers  24  having different optical properties may be used on a variety of different elements within the amusement park, such as on people and environmental elements, people and moving equipment, and so on, to facilitate separation for processing and monitoring by the control unit  18 . 
     Any one or a combination of the techniques set forth above may be used to monitor a single object or person, or multiple objects or people. Indeed, it is presently recognized that a combination of multiple retro-reflective marker grids (e.g., on the floor  92  and wall  93  as set forth above), or a combination of one or more retro-reflective marker grids and one or more tracked retro-reflective markers  24  fixed on a movable object or person, may be utilized to enable three-dimensional tracking, even when only one detector  16  is utilized. Further, it is also recognized that using multiple retro-reflective markers  24  on the same person or object may enable the tracking system  10  to track both position and orientation. 
     In this regard,  FIG. 9A  illustrates an embodiment of the object  26  having multiple retro-reflective markers  24  positioned on different faces of the object  26 . Specifically, in the illustrated embodiment, the retro-reflective markers  24  are disposed on three different points of the object  26  corresponding to three orthogonal directions (e.g., X, Y, and Z axes) of the object  26 . However, it should be noted that other placements of the multiple retro-reflective markers  24  may be used in other embodiments. In addition, the tracking depicted in  FIG. 9A  may be performed as generally illustrated, or may also utilize a grid of the retro-reflective markers  24  as shown in  FIG. 7 . 
     As noted above, the tracking system  10  may include multiple detectors  16  configured to sense the electromagnetic radiation that is reflected back from the object  26 , for example. Each of the retro-reflective markers  24  disposed on the object  26  may retro-reflect the emitted electromagnetic radiation beam  28  at a particular, predetermined frequency of the electromagnetic spectrum of the electromagnetic radiation beam  28 . That is, the retro-reflective markers  24  may retro-reflect the same or different portions of the electromagnetic spectrum, as generally set forth above with respect to  FIG. 8 . 
     The control unit  18  is configured to detect and distinguish the electromagnetic radiation reflected at these particular frequencies and, thus, to track the motion of each of the separate retro-reflective markers  24 . Specifically, the control unit  18  may analyze the detected locations of the separate retro-reflective markers  24  to track the roll (e.g., rotation about the Y axis), pitch (e.g., rotation about the X axis), and yaw (e.g., rotation about the Z axis) of the object  26 . That is, instead of only determining the location of the object  26  in space relative to a particular coordinate system (e.g., defined by the detection area  30  or the detector  16 ), the control unit  18  may determine the orientation of the object  26  within the coordinate system, which enables the control unit  18  to perform enhanced tracking and analyses of the movement of the object  26  in space and time through the detection area  30 . For instance, the control unit  18  may perform predictive analyses to estimate a future position of the object  26  within the detection area  30 , which may enable enhanced control over the movement of the object  26  (e.g., to avoid collisions, to take a particular path through an area). 
     In certain embodiments, such as when the object  26  is a motorized object, the tracking system  10  may track the position and orientation of the object  26  (e.g., a ride vehicle, an automaton, an unmanned aerial vehicle) and control the object  26  to proceed along a path in a predetermined manner. The control unit  18  may, additionally or alternatively, compare the results to an expected position and orientation of the object  26 , for example to determine whether the object  26  should be controlled to adjust its operation, and/or to determine whether the object  26  is operating properly or is in need of some sort of maintenance. In addition, the estimated position and orientation of the object  26 , as determined via the tracking system  10 , may be used to trigger actions (including preventing certain actions) by other amusement park equipment  12  (e.g., show effects). As one example, the object  26  may be a ride vehicle and the amusement park equipment  12  may be a show effect. In this example, it may be desirable to only trigger the amusement park equipment  12  when the object  26  is in the expected position and/or orientation. 
     Continuing with the manner in which tracking in three spatial dimensions may be preformed,  FIG. 9B  depicts an example of the object having a first marker  24 A, a second marker  24 B, and a third marker  24 C positioned in similar positions as set forth in  FIG. 9A . However, from the perspective of a single one of the detectors  16 , the detector  16  may see a two-dimensional representation of the object  16 , and the markers  24 A,  24 B,  24 C. From this first perspective (e.g., overhead or bottom view), the control unit  18  may determine that the first and second markers  24 A,  24 B are separated by a first observed distance d 1 , the first and third markers  24 A,  24 C are separated by a second observed distance d 2 , and the second and third markers  24 B,  24 C are separated by a third observed distance d 3 . The control unit  18  may compare these distances to known or calibrated values to estimate an orientation of the object  26  in three spatial dimensions. 
     Moving to  FIG. 9C , as the object  26  rotates, the detector  16  (and, correspondingly, the control unit  18 ) may detect that the apparent shape of the object  26  is different. However, the control unit  18  may also determine that the first and second markers  24 A,  24 B are separated by an adjusted first observed distance d 1 ′, the first and third markers  24 A,  24 C are separated by an adjusted second observed distance d 2 ′, and the second and third markers  24 B,  24 C are separated by an adjusted third observed distance d 3 ′. The control unit  18  may determine a difference between the distances detected in the orientation in  FIG. 9B  and the distances detected in the orientation in FIG.  9 C to determine how the orientation of the object  26  has changed to then determine the orientation of the object  26 . Additionally or alternatively, the control unit  18  may compare the adjusted observed distances d 1 ′, d 2 ′, d 3 ′ resulting from rotation of the object  26  to stored values to estimate an orientation of the object  26  in three spatial dimensions, or to further refine an update to the orientation determined based on the change between the distances in  FIGS. 9B and 9C . 
     As set forth above, present embodiments are directed to, among other things, the use of the disclosed tracking system  10  to track objects and/or people within an amusement park environment. As a result of this tracking, the control unit  18  may, in some embodiments, cause certain automated functions to be performed within various subsystems of the amusement park. Accordingly, having described the general operation of the disclosed tracking system  10 , more specific embodiments of tracking and control operations are provided below to facilitate a better understanding of certain aspects of the present disclosure. 
     Moving now to  FIG. 10 , an embodiment of a method  100  of monitoring changes in reflected electromagnetic radiation to track movement of a target and control amusement park equipment as result of this monitoring is illustrated as a flow diagram. Specifically, the method  100  includes the use of one or more of the emitters  14  (e.g., an emission subsystem) to flood (block  102 ) the detection area  30  with electromagnetic radiation (e.g., electromagnetic radiation beam  28 ) using the emission subsystem. For instance, the control unit  18  may cause one or more of the emitters  14  to intermittently or substantially continuously flood the detection area  30  with emitted electromagnetic radiation. Again, the electromagnetic radiation may be any appropriate wavelength that is able to be retro-reflected by the retro-reflective markers  24 . This includes, but is not limited to, ultraviolet, infrared, and visible wavelengths of the electromagnetic spectrum. It will be appreciated that different emitters  14 , and in some embodiments, different markers  24 , may utilize different wavelengths of electromagnetic radiation to facilitate differentiation of various elements within the area  30 . 
     After flooding the detection area  30  with electromagnetic radiation in accordance with the acts generally represented by block  102 , the method  100  proceeds to detecting (block  104 ) electromagnetic radiation that has been reflected from one or more elements in the detection area  30  (e.g., the retro-reflective markers  24 ). The detection may be performed by one or more of the detectors  16 , which may be positioned relative to the emitter  14  as generally set forth above with respect to  FIGS. 1 and 2 . As described above and set forth in further detail below, the features that perform the detection may be any appropriate element capable of and specifically configured to capture retro-reflected electromagnetic radiation and cause the captured retro-reflective electromagnetic radiation to be correlated to a region of the detector  16  so that information transmitted from the detector  16  to the control unit  18  retains position information regarding which of the markers  24  reflected electromagnetic radiation to the detector  16 . As one specific but non-limiting example, one or more of the detectors  16  (e.g., present as a detection subsystem) may include charge coupled devices within an optical camera or similar feature. 
     As described above, during the course of operation of the tracking system  10 , and while people  70  and/or objects  26 ,  32  are present within the detection area  30 , it may be expected that changes in reflected electromagnetic radiation will occur. These changes may be tracked (block  106 ) using a combination of the one or more detectors  16  and routines performed by processing circuitry of the control unit  18 . As one example, tracking changes in the reflected electromagnetic radiation in accordance with the acts generally represented by block  106  may include monitoring changes in reflected patterns from a grid over a certain period of time, monitoring changes in spectral signatures potentially caused by certain absorptive and/or diffusively or specularly reflective elements present within the detection area  30 , or by monitoring certain moving retro-reflective elements. As described below, the control unit  18  may be configured to perform certain types of tracking of the changes in reflection depending on the nature of the control to be performed in a particular amusement park attraction environment. 
     At substantially the same time or shortly after tracking the changes in reflected electromagnetic radiation in accordance with the acts generally represented by block  106 , certain information may be evaluated (block  108 ) as a result of these changes by the control unit  18 . In accordance with one aspect of the present disclosure, the evaluated information may include information pertaining to one or more individuals (e.g., amusement park guests, amusement park employees) to enable the control unit  18  to monitor movement and positioning of various individuals, and/or make determinations relating to whether the person is appropriately positioned relative to certain amusement park features. In accordance with another aspect of the present disclosure, the information evaluated by the control unit  18  may include information relating to objects  26 ,  32 , which may be environmental objects, moving objects, the amusement park equipment  12 , or any other device, item, or other feature present within the detection area  30 . Further details regarding the manner in which information may be evaluated is described in further detail below with reference to specific examples of amusement park equipment controlled at least in part by the control unit  18 . 
     As illustrated, the method  100  also includes controlling (block  110 ) amusement park equipment based on the information (e.g., monitored and analyzed movement of people and/or objects) evaluated in accordance with acts generally represented by block  108 . It should be noted that this control may be performed in conjunction with concurrent tracking and evaluation to enable the control unit  18  to perform many of the steps set forth in method  100  on a substantially continuous basis and in real-time (e.g., on the order of the rate of capture of the detector  16 ), as appropriate. In addition, the amusement park equipment controlled in accordance with the acts generally represented by block  110  may include automated equipment such as ride vehicles, access gates, point-of-sale kiosks, informational displays, or any other actuatable amusement park device. As another example, the control unit  18  may control certain show effects such as the ignition of a flame or a firework as a result of the tracking and evaluation performed in accordance with method  100 . More details relating to certain of these specific examples are described in further detail below. 
     In accordance with a more particular aspect of the present disclosure, the present embodiments relate to the tracking of retro-reflective markers positioned on certain environmental and functional features of an amusement park attraction area using survey equipment. For example, in certain embodiments, park equipment may be monitored for degradation due to mechanical and/or environmental stresses. Using this information, the control unit  18  may provide information relating to the current state of the particular equipment and, in some embodiments, may provide recommendations for maintenance or other procedures. More specifically, the amusement park equipment  12  may include various systems configured to provide such information to ride operators, facilities engineers, and so forth. For example, the amusement park equipment  12  that may be controlled in relation to surveying certain amusement park features may include displays, report-generating features, and the like. 
     In the specific context of an amusement park, the tracking system  10  may be disposed in surveying equipment  140 , as illustrated in  FIG. 11 , to determine a variety of maintenance-related information relating to roller coasters or similar rides, and/or relating to facilities housing certain amusement attraction features. In the illustrated embodiment, the surveying equipment  140  outputs the electromagnetic radiation beam  28  with a relatively large range to capture data representative of several different components in its field of view at the same time. These components may include, for example, supports  142  (e.g., ride column) of a roller coaster  144 , building structures  146 , and any other structures that may be in the field of view of the tracking system  10  within the surveying equipment  140 . Any number of these components may be equipped with one or more of the retro-reflective markers  24 . 
     In the illustrated embodiment, certain of the retro-reflective markers  24  are disposed on each of the supports  142  and the building structure  146 . The surveying equipment  140  may survey this series of retro-reflective markers  24  nearly instantaneously, since they are all within the field of view of the tracking system  10 . As described in further detail below, by evaluating the detected locations (both individual and in reference to each other) of the retro-reflective markers  24 , it may be possible to determine whether settlement of any of these supports  142  or the building structure  146  has occurred over time. In addition, since the surveying equipment  140  can take readings of multiple such retro-reflective markers  24  at the same time via the tracking system  10 , this may reduce the amount of time it takes to survey the area. 
     In accordance with a further embodiment, the tracking system  10  in the surveying equipment  140  may be used to determine whether a spectral shift has occurred over time on building structures  146  or other structures that have been painted. Specifically, the surveying equipment  140  may be used early on, when the building structure  146  has just been painted, to determine an amount of electromagnetic radiation reflected from the newly painted building structure  146 . At a later point in time, the surveying equipment  140  may be used to detect the electromagnetic radiation reflected from the building structure  146 , compare this reflected signature to the previously stored data, and determine whether spectral shift (e.g., paint fading) has occurred and if the building structure  146  should be repainted. 
     As also illustrated, the surveying equipment  140 , and specifically the tracking system  10 , may, in certain embodiments, be in communication with a diagnostic system  150 . In still further embodiments, the diagnostic system  150  may be integrated as a part of the surveying equipment  140  and/or implanted within the tracking system  10  (e.g., as a part of the control unit  18 ). As one example, the tracking system  10  may obtain tracking data relating to the retro-reflective markers  24  and/or other optically detectable features of the building  146  and/or ride  144 . The tracking system  10  may provide this information to the diagnostic system  150 , which may include processing circuitry  152  such as one or more processors configured to execute diagnostic routines stored on a memory of the system  150 . The memory may also include legacy information relating to prior analyses performed on the building  146  and ride  144 , so that the state of these features may be tracked and compared over time. 
     The diagnostic system  150  may also include an information system  154  in communication with the surveying equipment  140  and the processing circuitry  152 . The information system  154  may include various user interface features  156 , such as one or more displays  158  and/or one or more report generation features  160 . The user interface features  156  may be configured to provide users (e.g., operators, facilities engineers) with perceivable indicators relating to the evaluated health of the surveyed features and/or to provide the monitored data to the users to enable the users to analyze the data directly. However, it is within the scope of the present disclosure for the tracking system  10 , the surveying equipment  140 , and/or the diagnostic system  150  to analyze and interpret the monitored data to provide an indication to the users relating to whether the tracked amusement park feature is in need of maintenance. 
     Another example of the manner in which the surveying system  140  may be utilized in the context of evaluating a paint color and/or surface integrity of the building  146  is depicted in  FIG. 12 . Specifically,  FIG. 12  depicts a portion  170  of the building  146  at different time points. The different time points of the building  146  may be considered to represent, by way of example, the effect of time as well as environmental stresses on the building  146 .  FIG. 12 , as illustrated, includes the portion  170  at a first time point of the building  146 , which is represented as  146 A. 
     As shown at the first time point of the building  146 A, the portion  170  includes one of the retro-reflective markers  24  disposed underneath a surface treatment  172 . At the first time point, these are represented as portion  170 A and surface treatment  172 A. The surface treatment  172  may include, by way of example, a coating (e.g., paint) or a covering (e.g., brick, stucco). As shown, over time and upon exposure to various environmental stresses (e.g., weather, sunlight), the first surface treatment  172 A begins to fade, thin, crack, peel, or otherwise degrade to a second surface treatment  172 B (a degraded version of the first surface treatment  172 A), which results in a portion  174  of the retro-reflective marker  24  being exposed. 
     The surveying equipment  140 , and specifically the tracking system  10 , may recognize this change by determining that the retro-reflective marker  24  is able to receive and retro-reflect the electromagnetic radiation emitted by the emitter  14  of the tracking system  10 . The diagnostic system  150  may be configured to determine the degree to which the retro-reflective marker  24  has become exposed by, for example, tracking the intensity of the retro-reflected electromagnetic radiation and comparing the intensity to a stored intensity, pattern, etc. The diagnostic system  150  may also use the degree to which the retro-reflective marker  24  has become exposed to evaluate a relative degree of degradation of the surface treatment  172 . 
     As also illustrated, the portion  170  may also progress to a third portion  170 C having a third surface treatment  172 C (a further degraded version of the second surface treatment  172 B), where the retro-reflective marker  24  has become fully exposed. In such a situation, the tracking system  10  may recognize that the retro-reflective marker  24  has become fully exposed and may cause the information system  160  to provide a user-perceivable indication that the surface treatment  170 C may need to be re-applied or otherwise repaired. 
     In accordance with an aspect of the present disclosure, the surveying equipment  140  may, additionally or alternatively, be used to monitor a position of certain amusement park structural features, such as the supports  142  and/or a track  180  supported by the supports  142  as shown in  FIG. 13 . For example, over time, the supports  142  may settle into the ground  182 , and it may be desirable to recognize and/or monitor this settling over time to determine whether maintenance may be required on the ride  144 . Also, the track  180  on the supports  142  may also shift its position over time, for example by sagging or shifting horizontally due to gravity, use (e.g., vibrations), and other factors. 
     One or more of the retro-reflective markers  24  may be positioned on the supports  142 , the track  180 , and/or on the ground  182  (which may correspond to the floor  92  if the ride  144  is an indoor attraction). The retro-reflective markers  24  may be positioned on the supports  142  and the track  180  in regions where movement, degradation, sagging, settling, etc., is recognizable and/or most likely to occur. For example, as illustrated in  FIG. 13 , a plurality of retro-reflective markers  24  are positioned along a longitudinal axis of the supports  142 , while one of the retro-reflective markers  24  is positioned on a portion of the track  180  between the supports  142 , where settling or sagging might be most likely to occur. 
     The survey equipment  140  may, accordingly, identify a position of these markers  24  relative to a position of a certain environmental feature, such as the ground. The survey equipment  140  may include any number of features configured to perform surveying techniques and, indeed, the tracking system  10  of the present disclosure may simply be used in conjunction with such features, or in place of at least some of these features. By way of example, the survey equipment  140  may include any number of survey equipment features known in the art, such as a total station, a robotic total station, an electronic distance meter, a theodolite, or any combination of these or similar features. Furthermore, the control unit  18  may include or otherwise be in communication with various surveying circuitry  184 , including (but not limited to) distance analysis circuitry  186  and/or angle analysis circuitry  188  compatible with, for example, distance meters and theodolites. 
     As one non-limiting example, all or a part of the tracking system  10 , including the retro-reflective markers  24 , may be used in combination with electronic distance measurement techniques to evaluate shifting of the different features of the ride  144 . For instance, electronic distance measurement may generally be performed based on the emission of light, the detection of light reflected from a target, and the measurement of the phase difference between the emitted and reflected light. The phase difference can be used to determine the distance of the reflecting target from the emission source. Typically, one measurement would be performed at a time. However, in accordance with present embodiments, the detector  16  may be configured to capture multiple signals from multiple reflecting targets (i.e., multiple retro-reflective markers  24 ) without a loss of phase information. Accordingly, it is now recognized that the disclosed tracking system  10  may be integrated with existing surveying equipment and methodology to greatly enhance the speed by which survey measurement may be performed. It should be noted that equipment in accordance with present embodiments may also monitor vibration (e.g., slight shifts in equipment) during operation of the monitored system (e.g., a roller coaster). This may facilitate identification of components of the system (e.g., track segments) subject to increased wear. 
     As an example of the manner in which the tracking system  10  may be integrated with electronic distance measurement survey equipment to monitor shifting or excessive vibration of the ride  144 , the emitter  14  may emit the electromagnetic radiation beam  28  into the detection area  30  including the supports  142  and track  180 . The emission may be modulated using, for example, a quartz crystal oscillator that acts as an electronic shutter. The phase of the emitted electromagnetic radiation is, therefore, established by the system in accordance with present techniques. 
     The detector  16  may then capture and record the retro-reflected electromagnetic radiation from the retro-reflective markers  24  at substantially the same time. That is, the detector  16  may record both the source and the phase of the retro-reflected electromagnetic radiation from all of the retro-reflective markers  24  at once. This information may be provided to the surveying circuitry  184 , which may compare the measured phase to the known phase of the emitted radiation. The distance to the retro-reflective markers  24  may then be calculated based, at least in part, on the difference in phase between the transmitted and the received electromagnetic radiation. 
     The calculated distances for the retro-reflective markers on the supports  142  may be compared to the markers  24  on the track  180  to identify, for instance, movement of the track  180  relative to the supports  142  (assuming that the markers  24  were positioned for a prior measurement for comparative or baseline purposes, and the markers  24  are in the same position). Settling of the supports  142  may be identified, for instance, based on changing distances between the ground (on which a reflector may be positioned, as shown), and the measured retro-reflective markers  24  on the supports  142 . The supports  142  may also be measured relative to one another to identify whether one of the supports  142  might have moved relative to another, which could affect the track  180 . As set forth above with respect to  FIG. 11 , the information obtained from these types of surveys may be relayed to the information system  154  to enable a technician to address any potential issues with the surveyed equipment. 
     In addition to or as an alternative to monitoring the structural health of various amusement park equipment, the presently disclosed tracking system  10  may also be used to track pyrotechnic show effects produced by various equipment and, if appropriate, adjust the equipment producing the pyrotechnic show effects. Such tracking and control may be applied, for example, to the production of a flame effect, to a firework show, or other setting.  FIG. 14  illustrates an example of how the tracking system  10  may be used to identify and/or monitor a flame effect  200  (or some other heating effect). The flame effect  200  may be a part of an amusement park attraction such as a ride, a stunt show, or any other application where it is desirable to regularly provide a controlled flame. The flame effect  200  may, in certain embodiments, correspond to the production of a pattern of burning material, such as in a firework. 
     As discussed above with reference to  FIG. 1 , the control unit  18  of the tracking system  10  may be able to identify an object in the detection area  30  of the tracking system  10 , without the use of the retro-reflective markers  24 . That is, the control unit  18  may receive data indicative of the electromagnetic radiation reflected back from the detection area  30 , and the control unit  18  may compare the signature of the reflected radiation to one or more possible data signatures stored in memory  22 . In some embodiments, the control unit  18  may include a thermal signature stored in the memory  22 , this thermal signature corresponding to the light from the flame effect  200  that is expected to reach the detector  16  when the flame effect  200  is operating properly. This thermal signature may be generated and stored in the memory  22  by repeatedly testing the flame effect  200  and averaging the electromagnetic radiation detected via the detector  16  over those multiple tests. Then, when the ride is operating, the control unit  18  may compare a thermal signature of detected electromagnetic radiation  202  from the flame effect  200  with the thermal signature stored in the memory  22 . 
     The control unit  18  may trigger one or more pyrotechnic show effects based on a comparison made between the actual thermal signature detected via the detector  16  and the expected thermal signature. Specifically, if the thermal signature detected via the detector  16  is not approximately the same (e.g., within certain constraints) as the expected flame effect stored in the memory  22 , the control unit  18  may signal the amusement park equipment  12  to notify a ride operator that the flame effect  200  is not functioning correctly, to actuate a sprinkler system within the ride area, to shut down the ride, and/or to stop the flame effect  200  altogether. Depending on whether the detected thermal signature is much larger or smaller than the desired thermal signature, one or more of these effects may be triggered via the control unit  18 . 
     It should be noted that the same tracking system  10  (e.g., emitter  14  and detector  16 ) may simultaneously monitor both the flame effect  200  and other portions of the ride. For example, in the illustrated embodiment, the tracking system  10  is positioned to detect both the thermal signature of electromagnetic radiation from the flame effect  200  and a position of a ride vehicle  204  moving along the track  180 . To that end, the ride vehicle  204  may include one or more retro-reflective markers  24  disposed thereon for tracking the motion of the ride vehicle  204  via the same tracking system  10  that monitors the flame effect  200 , as long as the frequency of light reflected by the retro-reflective marker  24  is distinguishable from the flame effect signature. Due to the tracking system&#39;s ability to detect the retro-reflective marker  24  even in the presence of electromagnetic radiation including the wavelengths emitted by the emitter  14 , the electromagnetic radiation from the flame effect  200  does not prevent the control unit  18  from identifying and locating the retro-reflective marker  24  on the ride vehicle  204 . Thus, one tracking system  10  may be used to accomplish what would traditionally be accomplished using two or more distinct and functionally different detection systems, one for the flame effect  200  and another for the ride vehicle  204 . Similar techniques may be applied in other contexts where it is desirable to detect a location of one object located near a flame effect (or some other bright effect) (e.g., an ordinance during a firework display). 
       FIG. 15  illustrates an embodiment of the flame effect  200  and the manner in which the tracking system  10  may be used to control and adjust the operation of the flame effect  200 . Specifically, the flame effect  200  includes a flame-producing device  210 , which includes a nozzle  212  configured to mix a fuel provided from a fuel source  214  and an oxidant provided from an oxidant source  216 . The nozzle  212  may have a respective fuel inlet  218  and a respective oxidant inlet  220  configured to receive the fuel and the oxidant into the nozzle  212 . These may constitute the inlets of the flame-producing device  210 , or may be separate from the inlets thereof. 
     The flame-producing device  210  also includes a combustion chamber  222 , where the mixed fuel and oxidant are ignited using an ignition source  224  (e.g., one or more spark plugs). The combustion produces a flame  226 , which protrudes from an outlet  228  of the flame-producing device  210 . One or more flame additives from a flame additive source  230  may be added to the flame  226  to adjust the color of the flame  226 . For example, the flame additives may include metal salts, which may change the color of the flame  226  from orange and red to blue, green etc. 
     The control unit  18 , using one or more of the detectors  16 , may monitor the optical qualities of the flame  226  and, as a result of this monitoring, may perform certain control actions to adjust the flame  226  as appropriate. For example, the control unit  18  may be communicatively coupled to any one or a combination of the fuel source  214 , oxidant source  216 , ignition source  214 , and flame additive source  230  to adjust the flame  226 . As also illustrated, control unit  18  may include flame analysis circuitry  232 , including flame shape analysis circuitry  234  configured to analyze a shape of the flame  226 , flame timing analysis circuitry  236  configured to analyze a timing of the flame  226 , and flame color analysis circuitry  238  configured to analyze the colors of the flame  226 . The control unit  18 , as an example, may control an amount of fuel and/or oxidant provided to the nozzle  212  by controlling the fuel and/or oxidant sources  214 ,  216 . Similarly, the control unit  18  may control the timing of the flame  226  by adjusting the ignition source  224 , and may adjust a color of the flame  226  by adjusting a flame additive provided by the flame additive source  230  (e.g., an amount of the additive) and/or the fuel source  214  (e.g., a flow of the fuel) and/or the oxidant source  216  (e.g., a flow of the oxidant). 
     Similar applications exist for equipment incorporating the tracking system  10  disclosed herein. For example, as illustrated in  FIG. 16 , the tracking system  10  may be used to control a firework (or ordinance) show  240  performed in a pyrotechnic show area, for example to enable enhanced monitoring and control of firework timing. Indeed, the tracking system  10  may use aspects relating to surveying (e.g., distance measurement) as well as flame monitoring in controlling the firework show  240 . Since there may inherently be some variability between how long after a fuse is lit before the individual ordinance will ignite and explode as a firework, as well as how high the ordinance has traveled upward prior to ignition, it is now recognized that more accurate systems for controlling the height at which these ordinances reach before ignition is desired. This may produce a more consistent show. 
     In accordance with present embodiments, the tracking system  10  may be used to detect and track an ordinance  242  as it travels upward through the air. The tracking system  10  may send a signal indicative of the height of the ordinance above the ground  182  to a remote detonation system  244 , which may communicate wirelessly with a detonator in the ordinance  242 . When the ordinance  242  reaches a desirable height  246  above the ground, the remote detonation system  244  may send a wireless signal to the detonator in the ordinance  242  to initiate ignition and explosion of the ordinance  242  at approximately the desired height  246 . 
       FIG. 17  illustrates an example embodiment of the ordinance  242  and the manner in which the tracking system  10  may track the ordinance  242  during flight. As illustrated in  FIG. 17 , the ordinance  242  includes an outer casing  260  enclosing various features of the ordinance  242 . In certain embodiments, the internal features include a fuse  262  (which also extends out of the casing  260 ), which is lit and is used to ignite a lift charge  264 . The lift charge  264  is typically responsible for the height that the ordinance  242  will reach in the air. However, as set forth below, the ordinance  242  may be launched using other features, such as compressed air. Accordingly, the ordinance  242  may not include the fuse  262 . The presently disclosed ordinance  242  may include electronic detonator features (e.g., an electronic fuse mechanism), such as an electronic detonator  266  and a transceiver  268  configured to receive detonation signals from the remote detonation system  244 . The ordinance  242  may include an internal fuse  270  connected to the electronic detonator  266 , or a standalone fuse  271  coupled to the lift charge  264 . The electronic detonator  266  may be configured to ignite a burst charge  272  via the internal fuse  270 . However, other embodiments may utilize the standalone fuse  271  that is not coupled to an electronic feature for detonation. The burst charge  272  causes a plurality of pyrotechnic features (pyrotechnic show elements) commonly referred to as “stars”  274 , to be released and burned. Typically, the stars  274  include a mixture of metal salts that, when burned, produce color. 
     As also illustrated, one or more of the retro-reflective markers  24  may be positioned on the outer casing  260 . The marker  24  may enable the tracking system  10  to track the ordinance  242  after the lift charge  264  is ignited and while the ordinance  242  is in the air. For example, the emitter  14  and the detector  16  may be positioned on the building  146 , and the detector  16  may track the marker  24  through the flight of the ordinance  242  to determine how high the ordinance  242  was before it burst. The triggering of the pyrotechnic show elements may be detected by the control unit  18 , for example, by detecting a pattern of electromagnetic radiation associated with the pyrotechnic show elements (the stars  274 ) stored in the memory  22 . The control unit  18  may be configured to determine a location at which the ordinance  242  detonated based on the detected triggering of the pyrotechnic show elements. Additionally or alternatively, the control unit  18  may track the movement of the ordinance  242  through the air (i.e., track its trajectory), and identify a triggering event of the ordinance  242  (detonation of the ordinance  242 ) when the retro-reflective marker  24  on the enclosure  260  is no longer visible to the detector  16  (e.g., termination of the retro-reflection by the retro-reflective marker  24  is associated with detonation of the ordinance  242 ). 
     Additionally or alternatively, the control unit  18 , using routines stored in memory  22  and executed by processor  20 , may track the ordinance  242  and relay instructions to the remote detonation system  244  to initiate detonation of the ordinance  242 . Specifically, the remote detonation system  244  may include processing circuitry such as one or more processors  280  configured to, using instructions stored in one or more memory  282 , interpret signals (e.g., data, instructions) from the control unit  18 . As a result, the remote detonation system  244  may send wireless control signals from a transceiver  284  and to the respective transceiver  268  of the ordinance  242  to initiate detonation using the detonation electronics. As one example, the control unit  18  may provide either or both of height data and/or explicit detonation instructions. 
     The tracking system  10  may also be used to adjust ordinance trajectory, where appropriate. For example, as shown in  FIG. 18 , the tracking system  10  may track a plurality of the ordinances  242  as they travel through the air by tracking the retro-reflective markers  24  positioned on their casings  260  (see  FIG. 17 ). The ordinances  242 , in some embodiments, may be fired from cannons  290  mounted on robotic arms  292  attached to a base  294  on the ground  192 . The robotic arms  292  may have articulation  296  along at least one axis, for example between one and six, to allow the ordinances  242  to be fired along any appropriate trajectories for the firework show  240 . 
     In operation, the tracking system  10  may track the ordinances  242  and may also track their associated burst patterns  298  to determine launch trajectory and the location where the ordinances  242  ultimately detonated using, for example, firework trajectory control circuitry  300 . In certain embodiments, the control unit  18  may have a predetermined firework show sequence stored in memory  22  (see  FIG. 1 ), where the show sequence includes associated burst patterns, timing, trajectory, and so forth. The control unit  18  may perform substantially real-time comparisons between the tracked locations of the ordinances  242  and their burst patterns  298  to stored locations and associated burst patterns, and the timing associated with this stored information, and, using the trajectory control circuitry  300 , cause actuation of the robotic arms  292  to adjust a position of the cannons  290 . The adjustment may be performed so that the monitored trajectories of the ordinances  242  and locations of burst patterns  298  are appropriately correlated to the corresponding information stored in memory  22  associated with the stored firework show. 
     As noted above, in certain embodiments, the ordinance  242  may not include a lift charge. Instead, the ordinance  242  may be launched out of the cannons  290  using a compressed gas (e.g., compressed air) provided by a compressed gas source  302 . In this regard, the amount of compressed gas (e.g., a pressure of the compressed gas) provided to the cannons  290  may determine, at least in part, a trajectory of the ordinance  242  through the air, how high the ordinance  242  is before it detonates, and so forth. As illustrated, the control unit  18  may be communicatively coupled to the compressed gas source  302 , and may adjust the amount of compressed gas provided by the compressed gas source  302  to the cannons  290  to adjust a launch velocity of the ordinance  242  out of the cannons  290 . For example, such adjustments may be provided based on comparisons between an expected (e.g., stored, reference) trajectory of the ordinance  242  and a measured trajectory of the ordinance  242 . In this way, subsequent ordinances  242  having substantially the same configuration as the tracked ordinances  242  may have trajectories that are adjusted by the control unit  18  to more closely match the stored or reference trajectory. 
     While only certain features of the present embodiments have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.