Abstract:
A method and apparatus for inspecting items for the presence of contraband. Trays may be used to hold items as they move through an inspection station. After use, the trays may be mechanically conveyed back to an entry region of the inspection station so that the trays may be used to move other items. Mechanically conveying the trays may enable increased throughput for inspection stations. A tray return may be constructed from multiple modules positioned to the side of an inspection machine. In use at an airport or other similar facility, the tray return may face a passenger use area at an inspection station. Passengers exiting the inspection station may place trays in the tray return. Passengers entering the inspection station may remove a tray from an end of the tray return at an entrance of the inspection station.

Description:
RELATED APPLICATIONS 
     This application is a continuation-in-part of International Application PCT/US2005/027831, which claims benefit under 35 U.S.C. § 119(e) to U.S. Provisional Application Ser. No. 60/598,934, entitled “INCREASED THROUGHPUT INSPECTION STATION,” filed on Aug. 5, 2004, which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND OF INVENTION 
     1. Field of Invention 
     The invention relates generally to inspection stations such as those used at airports to screen luggage for explosives or other contraband. This invention relates more specifically to increasing the rate at which items may flow through inspection stations. 
     2. Discussion of Related Art 
     Inspection stations are often used to screen baggage, such as carry-on baggage, at airports and secure facilities. In some inspection stations, carry-on baggage and other items may be placed on trays, and the trays may be placed on a conveyor belt to be moved through an inspection region. 
       FIG. 1  illustrates an example of an existing inspection station such as may be used at an airport to screen carry-on baggage. Inspection station  100  includes an inspection region  110 . In many cases, items in inspection region  110  may be scanned using an x-ray line scanner that forms an image of objects as they are moved through the inspection region. 
     The image may typically be displayed at a work station  112  for a human operator  114  to observe. Human operator  114  may clear an item and allow it to pass through the inspection station if no suspicious areas appear in the image. If suspicious areas appear in the image, the item may be required to undergo other levels of inspection, such as a physical search of the item. 
     Inspection station  100  may include a conveyor  120 . Conveyor  120  may be a moving belt propelled by one or more motors, illustrated schematically as motor  302 . Conveyor  120  may move items through inspection region  110  in such a way that images of the items can be formed. 
     To contain and/or protect items being passed through inspection region  110 , trays, such as trays  130 A,  130 B and  130 C are often provided at the inspection station. For example, passengers passing through an airport security checkpoint will often place keys, coins and other small objects in trays so they are not lost as they are moved through inspection region  110 . 
     Passengers also may place coats, shoes, belts or other items of clothing in trays  130  so they are not damaged as they pass through inspection region  110 . 
     As a further example, passengers may place cell phones, PDA&#39;s and other portable electronic devices in trays, which may enable a more thorough inspection of the items. 
     Typically, a stack of trays is provided at the entry region of the inspection station. Passengers may place their items in a tray  130  and set the tray on conveyor  120 , which moves the tray and the items through the inspection region  110  to an exit region on the other end of the inspection station. The trays  130  may accumulate at the exit region until an operator carries them back to the entry point of the inspection station. 
     SUMMARY OF INVENTION 
     In one aspect of the invention, items are inspected according to a method that includes mechanically conveying trays from an exit region to an entry region of the inspection station. 
     In another aspect, the invention relates to a method of inspecting items. The method includes moving the items on trays from a first region to a second region through an inspection region. The method also includes inspecting the items to detect contraband. The method further includes mechanically conveying the trays from the second region to the first region. 
     In yet another aspect, the invention relates to an inspection station for detecting contraband within items. The inspection station includes a first region, a second region, and an inspection region. The inspection station also includes a first conveyance system to convey the items on trays from the first region to the second region through the inspection region. The inspection station further includes a second conveyance system to convey the trays from the second region to the first region. 
     In a further aspect, the invention relates to an inspection station for detecting contraband within items. The inspection station includes a first region, a second region, and an inspection region. The inspection station also includes a first conveyance system to convey the items on trays in a first direction from the first region to the second region through the inspection region. The inspection station further includes a second conveyance system to convey the trays from the second region to the first region. The second conveyance system is offset from the first conveyance system in a direction perpendicular to the direction in which the trays move. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings: 
         FIG. 1  is a sketch of a prior art inspection station; 
         FIG. 2  is a side view of an inspection station according to one embodiment of the invention; 
         FIG. 3  is a side view of an inspection station according to an alternative embodiment of the invention; 
         FIG. 4A  is a side view of an inspection station according to an alternative embodiment of the invention; 
         FIG. 4B  is a side view of an inspection station according to an alternative embodiment of the invention; 
         FIG. 5A  is a sketch of a further alternative embodiment of the invention; 
         FIG. 5B  is a side view of the inspection station of  FIG. 5A ; and 
         FIG. 6  is a sketch of a segment of a tray return according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Inspection stations are often used with trays that may hold items moving through the inspection station. The inventors have appreciated that it may undesirable for a human operator to carry trays from an exit region near the end of a conveyor back to the entry region of an inspection station. For example, passengers may be required to wait while the human operator carries the trays, which may be a source of frustration for passengers or others required to pass through the inspection station. As another example, requiring a human operator of the inspection station to move trays may distract the operator from providing security and ensuring the integrity of the inspections carried out at the inspection station. 
     In one aspect of the invention, trays may be mechanically conveyed from an exit region to an entry region of an inspection station. The entry region may be the region near the beginning of conveyor  120  ( FIG. 1 ) where items may be placed on trays  130  ( FIG. 1 ), and where the trays may be placed on conveyor  120 . The exit region may be the region near the end of conveyor  120  where items may be collected after they have been inspected. Mechanically conveying the trays may increase the throughput of the inspection station. 
     As used herein, the term mechanically conveying means imparting motion to an object in a mechanical system such that the object is moved from one position to another position. In some embodiments, motors, actuators and other powered mechanisms that provide motive force may be used to input motion. However, the force of gravity may also be used to impart motion to an object placed on a low-friction inclined surface. Further a human pushing an object through a conduit in a mechanical system providing a low-friction surface is another mechanism for impairing mechanical motion. Any suitable mechanism to impart mechanical motion may be used. 
     An embodiment of the invention is illustrated in  FIG. 2 . As in the system of  FIG. 1 , inspection station  200  includes an inspection region  110 . A conveyor  120  may move a tray  130 A containing items under inspection through inspection region  110 . To provide a tray return, inspection station  200  incorporates a conveyor  220  that may move in the opposite direction of conveyor  120 . As trays such as  130 A and  130 B reach the end of conveyor  120  and items are removed from the trays, the trays can be placed on conveyor  220  that may return the trays to the entry region of the inspection station. 
     Conveyor  220  may be a belt type conveyor similar to conveyors currently used in x-ray inspection stations and may be propelled by one or more motors, such as motor  304 . However, any suitable mechanical conveyance means may be used. Other possibilities include using a rubberized band, a chain or other system of linkages with a means, such as a hook, to engage a tray. As a further example, conveyor  220  may be implemented as a series of rollers placed at an incline such that a tray  130 B on conveyor  220  in the exit region of inspection station  200  may slide down conveyor  220  without human interaction. Further, it is not necessary that trays such as  130 A and  130 B rest on conveyor  220 . Conveyor  220  may impart motion to a tray such as tray  130 B by lifting or pulling the tray. For example, a motorized trolley may run on a track and the trolley may include a hook or other attachment mechanism to attach it to a tray  130 . 
       FIG. 3  shows an alternative embodiment. In this embodiment, conveyor  120  is preceded by a non-motorized segment  310  and followed by a non-motorized segment  312 . Such non-motorized segments may enable trays to be moved relatively easily toward belt  120  or away from belt  120 . These non-motorized segments  310  and  312  may include, for example, a series of rollers  314  or other low friction surface on which trays may readily slide. Trays may easily slide on the rollers and the speed of the trays on the non-motorized portions need not match the speed of conveyor  120 . These non-motorized segments may act as holding areas for trays conveying items waiting to be inspected or waiting to be reclaimed after inspection. 
     A similar arrangement may be used on conveyor  220 . Conveyor  220  may be motorized, and may be followed by a non-motorized segment  322  that forms a holding area for empty trays. Trays may be pushed by the motion of motorized conveyor  220  to the holding area formed by non-motorized segment  322 . Trays on conveyor  220  may generally move at a speed dictated by the motor for conveyor  220 . However, because non-motorized segment  322  may not be coupled to the motorized segment, trays could move through the holding area created by non-motorized segment  322  at a rate dictated by the rate at which the trays are being removed from the holding area for use in passing items through inspection station  300 . 
     Other ways to construct a holding area for trays exiting conveyor  220  may also be used in place of or in addition to a non-motorized segment of a belt. For example, a holding area for trays may be created by simply stacking the trays. Generally, trays used in inspection stations may be designed to nest, one inside the other. Trays may be nested simply by allowing them to fall off the end of the conveyor. Alternatively, a robotic arm or some other automated structure could remove trays from the conveyor and stack them in a holding area. 
       FIGS. 4A and 4B  illustrate further alternative embodiments. Trays traveling on conveyor  220  may usually be empty. Therefore, it is not necessary that trays on conveyor  220  retain the same orientation that they have on conveyor  120 . In the embodiments of  FIGS. 4A and 4B , the bottom of the tray is generally planar and adapted to rest on conveyor  120  as the trays move through inspection region  110 . In the tray return, the trays are oriented with their bottoms vertical. 
       FIG. 4A  shows that trays, such as trays  130 A and  130 B, are placed on conveyor  120  with the bottom of the tray against conveyor  120 . In the tray return, trays such as  130 C,  130 D, and  103 E are placed on their side such that a narrow dimension of the tray is parallel to conveyor  220 . Such a configuration may allow more trays to be held in a holding area, such as non-motorized segment  422 . 
       FIG. 4B  shows an alternative configuration for the trays on the return conveyor.  FIG. 4B  shows trays such as  130 C and  130 D on the return conveyor  220  with a narrow dimension parallel with the width of belt  120  and their bottoms vertical. Such a configuration may be desirable when limited space is available under inspection region  110  or when the tray return system is positioned to the side of conveyor  120 . 
     The desired orientation of the trays may be achieved by providing slots, rails or other features to hold trays in the desired orientation on conveyor  220 . The trays may be moved into the desired orientation in any suitable way. As one example, a robotic arm or other mechanical assembly may provide a means for placing the trays on conveyor  220  with the desired orientation. However, conveyor  220  may be positioned so that a human operator of the inspection station may place the trays on conveyor  220 . As an example of a further alternative, conveyor  220  may be positioned so that a person carrying items to the inspection station may place trays on conveyor  220  after they have passed through inspection region  110 . 
       FIG. 5A  shows a further alternative embodiment of an inspection system with a tray return.  FIG. 5A  shows an x-ray scanner  550  with an inspection region  510 . A conveyor  520  moves items under inspection through inspection region  510  with an x-ray scanner  550 . 
     In the pictured embodiment, items under inspection move through inspection area  510  in the direction  570 . An input holding area  514  may be formed from a set of rollers or other mechanism that forms a low friction surface on which items under inspection may be easily slid towards conveyor  520 . In the embodiment illustrated, scanner  550  may be located at a security checkpoint screening passengers about to board a vessel, such as an airplane, train, ship or bus. Passengers may load trays with items under inspection and slide them through input holding area  514 . 
     Similarly, an output holding area  512  may be formed so that items under inspection may easily slide away from conveyor  520 . Items can be held stationary in output holding area  512  until removed, allowing passengers to retrieve items that have been inspected from trays held in output holding area  512 . 
     The inspection system of  FIG. 5A  includes a tray return mechanism  520 . Tray return mechanism  520  allows trays used to hold items under inspection to be returned to the input area of the inspection system. Accordingly, trays may move in direction  572  through tray return  520  from end  580  to end  582 . 
     In the embodiment illustrated, tray return  520  forms a mechanical conveyance system. Tray return  520  may be motorized or non-motorized. In a motorized embodiment, motor driven rollers in tray return  520 , or any other suitable mechanism, may be used to drive the trays. In a non-motorized embodiment, any suitable means may be employed to impart motion to trays in direction  572 . As one example, tray return  520  may be sloped so that the force of gravity pulls trays in direction  572 . Alternatively, tray return  520  may be designed to provide a low-friction surface so that trays may be easily pushed in direction  572 . Tray return  520  may be designed so that a person wishing to place a tray at end  580  can easily push other trays already in tray return  520  in direction  572  to make room for another tray. 
     As another example of how motion may be imparted to trays in tray return  520 , tray return  520  may be constructed with a camming mechanism or other similar structure that translates a downward motion of a tray being placed at end  580  of tray return  520  into lateral motion in direction  572  of the trays already in tray return  520 . In such an embodiment, a passenger may remove a tray from end  582  of tray return  520  and use the tray for loading items to be passed through inspection region  510 . As passengers retrieve their items after inspection, they may place the trays into tray return  520  at end  580 . Trays previously placed in tray return  520  at end  580  may then be pushed in direction  572  so that they are available for use at end  582 . The force for pushing trays in direction  572  may come from a passenger or other person directly pushing on the trays. 
     In the embodiment illustrated, x-ray scanner  550  has an operator side  552  and a passenger side  554 . In the embodiment pictured, tray return  520  is positioned on passenger side  554  of x-ray scanner  550 . This configuration allows tray return  520  to deliver trays directly to passengers wishing to load items under inspection into x-ray scanner  550  at end  582 . Positioning tray return  520  on passenger side  554  also allows passengers to operate the tray return mechanism as they unload their items from x-ray scanner  550 . 
       FIG. 5B  shows a side view of x-ray scanner  550  as seen from passenger side  554 . As can be seen in  FIG. 5B , a series of trays  130 A,  130 B . . .  130 K fills tray return  520  between ends  580  and  582  so that pushing on a tray, such as tray  130 A, at end  580  would push the remaining trays towards end  582 . In embodiments in which tray return  520  is motorized, trays placed at end  580  may be moved to end  582  without being pushed. 
     As can be seen in  FIG. 5B , tray return  520  is positioned so that trays  130 A,  130 B . . .  130 K are below upper surfaces of input holding area  514 , conveyor  520  and output holding area  512 . In this way, both ends of tray return  520  are readily accessible to a passenger, but no part of tray return  520  blocks access to x-ray scanner  550  at end  580 . Accordingly, tray handling may be performed by passengers, reducing or eliminating the need for an operator of x-ray scanner to be involved in the tray handling process. 
     In the embodiment pictured in  FIGS. 5A and 5B , tray return  520  is constructed from multiple segments  530 A,  530 B . . .  530 F. Each of the segments may be identical. However, it is not necessary that each of the segments be identical. For example, end segments  530 A and  530 F may be constructed with stops to prevent trays from falling out of tray return  520 . Also, end segments  530 A and  530 F may, be designed to allow trays to be inserted or removed in a vertical direction. 
     Any suitable number of segments may be used to construct tray return  520  and more or less segments may be used to provide a desired length. In the embodiment illustrated in  FIGS. 5A and 5B , tray return  520  spans from output holding area  512  to input holding area  514 . If the inspection system pictured in  FIGS. 5A and 5B  were expanded to include tables, benches or other surfaces either preceding input holding area  514  or following output holding area  512 , tray return  520  may include additional segments extending its length to span from any position at which items are unloaded from trays to any position at which items are loaded into trays. 
     To facilitate tray return  520  having any desired size or position, in some embodiments, tray return  520  may be constructed separately from x-ray scanner  550 . If constructed separately, tray return  520  may be mounted on casters or other similar rolling device that allows it to be easily moved. If tray return  520  is easily movable, it may also contain a mechanism to hold it in place relative to x-ray scanner  550 . However, in other embodiments, tray return  520  may be constructed as a component of x-ray scanner  550 . Accordingly, the specific connection between tray return  520  and x-ray scanner  550  is not a limitation of the invention. 
       FIG. 6  shows a segment  630  that may be used to form a segment of tray return  520 . In the embodiment illustrated in  FIG. 6 , segment  630  forms a conduit  670  through which trays may pass in direction  672 . 
     As pictured, conduit  670  has a low friction floor, allowing trays to easily slide through conduit  670 . In the embodiment pictured, the floor of conduit  670  is formed from multiple parallel rollers  640 . Each of the rollers may freely turn, allowing trays to easily slide across the rollers to pass through conduit  670 . Alternatively or additionally, some or all of the rollers  640  may be driven by one or more motors or similar devices. 
     Conduit  670  may be further bounded by other components of segment  630 . In the embodiment pictured in  FIG. 6 , rails  642  and  644  provide side boundaries on conduit  670  and aid in holding trays with their bottoms in a vertical orientation as pictured in  FIG. 5B . Rails  642  and  644  may be constructed of any suitable material. In one embodiment, rails  642  and  644  are formed of metal that is bent into a desired shape. As shown, each of the rails  642  and  644  has an elongated horizontal member and multiple vertical members that are affixed to the floor of conduit  670 . However, any suitable construction techniques may be used to form rails  642  and  644 . 
     As pictured in  FIG. 6 , segment  630  includes a front skin  632 . Skin  632  may be a relatively thin sheet of metal, plastic or other suitable material. Skin  632  may be partially cosmetic, providing a more finished appearance to segment  630 . However, in some embodiments, skin  632  may be structural and/or functional. As shown, front skin  632  is attached to rail  644 . If front skin  632  is formed of a material with sufficient strength, it may provide structural rigidity to rail  644 . Additionally, front skin  632  may also function to prevent items from being inserted into conduit  670  and interfering with motion of trays through segment  630 . Likewise, front skin  632  may prevent trays within conduit  670  from rotating within conduit  670 , thereby becoming jammed on vertical members of rail  644 . 
     Segment  630  may also include a back skin  634 . Back skin  634  may likewise be constructed of sheet metal, plastic or other suitable material. Back skin  634  may be attached to rail  642  and may function similarly to front skin  632 . Alternatively or additionally, back skin  634  may be attached to inspection equipment, such as x-ray scanner  550  ( FIG. 5A ), instead of or in addition to a skin as is conventionally used to cover inspection equipment. 
     In the pictured embodiment, back skin  634  contains a shelf  636  that provides a cover over conduit  670 . Shelf  636  precludes objects from being inserted into conduit  670  from above and interfering with the motion of trays through conduit  670 . 
     Back skin  634  also may be shaped to aid in retaining trays within conduit  670 . In the pictured embodiment, shelf  636  includes a lip  638 . Lip  638  may engage an upper edge of trays within conduit  670 , thereby preventing the trays from rotating forward out of conduit  670 . 
     However, it is not a limitation of the invention that segment  630  be used with trays tall enough to engage lip  638 . In the embodiment pictured, the position of shelf  636  defines the upper limit on the size of trays that may pass through conduit  670 . Shorter trays may readily pass through conduit  670  and may be readily retained within conduit  670  by rails  642  and  644 . 
     More generally, segment  630  is not limited to handling trays of any specific size. Conduit  670  has boundaries that limits the size of trays that may pass through it. However, conduit  670  may convey trays of any size that do not exceed those limits. Moreover, embodiments may be constructed without shelf  636 , which would remove a constraint on the length of trays that may be carried by segment  630 . 
     To promote modular assembly of a tray return, segment  630  may be supported by casters, of which casters  650 A and  650 B are visible in  FIG. 6 . In some embodiments, at least three casters are used per segment. In the embodiment pictured, segment  630  includes four casters, one positioned proximately in each corner of segment  630 . Casters are an example of a mechanism to facilitate both easy movement of segment  630 . Easy movement of a tray return allows the tray return to be configured in any desired location as part of an inspection station. It also allows a tray return to be removed for access to equipment in the inspection station for maintenance or other reasons. 
     Casters  650  are an example of a mechanism for fixing the position of segment  630  once it is in a desired position. Casters  650  may be casters as are conventionally available that have a locked and unlocked position. When unlocked, caster  650  roll freely, allowing segment  630  to be moved into position as part of a tray return. When locked, the casters may hold segment  630  in position. However, different or additional mechanisms may be used to hold segment  630  in position when forming a tray return. 
     If multiple segments such as segment  630  are used to form a tray return, each segment may include a mechanism  531  to engage an adjacent segment forming a portion of the tray return. Alternatively or additionally, segments may be constructed to engage support members that hold each segment in its desired position. In some embodiments, the inspection system may form the support member, and segments, such as segment  630 , forming a portion of a tray return may include a mechanism to engage an inspection system or other component of an inspection station. 
     Additionally, each of the casters may have an adjustable height. The height of the casters may be independently adjusted to compensate for any irregularities in the height of the surface on which segment  630  rests. Alternatively, the height of casters on segment  630  may be adjusted to mount segment  630  with a downward slope in direction  672  so that the force of gravity urges trays within segment  630  to move in direction  672 . Such a slope may be imparted, for example, by adjusting caster  650 A to have a height greater than that of caster  650 B. If a sufficient slope is provided, motorized rollers and other structures to drive trays through the tray return may be omitted. 
     Having thus described several aspects of at least one embodiment of this invention, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art. 
     The foregoing are intended to be examples of embodiments of the invention. Various alternatives may be made. For example, it is not necessary that return conveyor  220  be physically separate from conveyor  120 . While the upper surface of conveyor  120  carries items from the input of the inspection station to the exit point of the inspection station, the lower surface of conveyor  120  moves in the opposite direction and can be used to propel trays back to the entry point of the inspection station. The trays may be coupled to the underside of belt  120  in any convenient manner such as by hooks or other fasteners. 
     Further, an x-ray line scanner is used as an example of a scanner used to inspect items at an inspection station. A computed tomography system and/or other types of inspection equipment may be used in place of a line scanner. Further, other types of radiation may be used to form images, e.g., gamma rays. Further, it is not necessary that inspection station  100  form images of objects. Other scanning technologies may be employed. For example, inspection regions that detect certain types of chemicals may be used. 
     Also, an inspection station with only one scanner is pictured. The inspection station may include several inspection systems, with a single tray return used to return trays that have passed through any of multiple scanners. For example, inspection stations used at airports to screen carry-on baggage often include several x-ray scanners arranged in a parallel configuration. Some passengers may have items that are inspected by one x-ray scanner and some passengers may have items that are inspected by a different x-ray scanner. An attendant may, for example, direct a passenger to an x-ray scanner that has the shortest line. 
     In one aspect of the invention, an inspection station may include a single device to mechanically convey trays back to an entry region of the inspection station. For example, trays may pass through several different x-ray scanners to an exit region of the inspection station, but may all be mechanically conveyed from the exit region to the entry region on the same conveyor belt. However, any suitable number of devices for mechanically conveying trays may be used, e.g., several conveyor belts. 
     As another example, an item may be inspected by multiple inspection systems before reaching an exit region of the inspection station. For example, an item may be scanned by two different types of inspection systems, such as two different types of x-ray scanners (e.g., a line scanner and a CT scanner), or an x-ray scanner and a chemical analysis system that detects traces of explosives. In inspection stations where an item is inspected by multiple inspection systems, the distance from the exit region to the entry region of the inspection station may be relatively great but a system according to an embodiment of the inventor may be used for tray return, avoiding the need for a human operator to carry trays a relatively great distance from the exit region to the entry region. 
     However, it is not necessary that the inspection station have a human operator as illustrated in  FIG. 1 . Inspection may be performed through automated threat recognition software on a computer associated with the inspection region, or with some combination of automated software and human review. 
     As another example, the inspection station may have a remote human operator. The remote human operator may be stationed at a remote location, such as across the room from the inspection station, in a different room than the inspection station or even in a different building or facility. The remote human operator may perform various tasks that a human operator may often perform while stationed in close proximity to the inspection station, e.g., viewing images of items on a display, identifying threats, and monitoring the inspection station for suspicious activity. Performing such tasks remotely may be enabled by transferring data via a network connection from the inspection station to a remote workstation. As described above in connection with the embodiments of  FIGS. 5A and 5B , a tray return may be positioned to allow passengers passing through an inspection station to both obtain trays and return them to the entry point of the inspection station. Such an embodiment of a tray return may be used with an inspection machine networked for remote operation, reducing or eliminating the need for human operations an a message station. 
     Mechanically conveying trays may provide for an environment in which a human operator stationed in close proximity to the inspection station may be replaced with a remote human operator. As a result of the trays being mechanically conveyed, the human operator may not need to be stationed in close proximity to the inspection station to manually carry the trays. 
     Also, “trays” are not limited in shape or size to the examples illustrated. A “tray” may be any component used for support of items moving through an inspection system. 
     This invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having,” “containing,” “involving,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. 
     Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description and drawings are by way of example only.