Abstract:
A system and method for mass, automated scanning of objects, including dental study casts, housing parts, and other objects. The system and method are able to function with little or no human operator intervention, thereby facilitating high volume scanning and reducing scanning costs. The system includes a scanner having a scanning table, a conveyor mechanism adjacent the scanner for delivering objects to be scanned to the scanner, and a pick and place mechanism for taking an object from the conveyor mechanism and mounting it onto the scanning table of the scanner.

Description:
[0001]    This application claims priority from provisional application Serial No. 60/288,905, filed May 4, 2001, and which is incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates generally to scanning of objects. More particularly, the invention relates to mass automated scanning of objects, such as dental study casts, housings for electronic devices including cellular telephones and electronic organizers, and other objects.  
         BACKGROUND OF THE INVENTION  
         [0003]    Scanning of three-dimensional objects is generally known from the prior art. As disclosed in commonly assigned U.S. Pat. No. 6,217,334, dental study casts are scanned, and the data obtained from scanning the study casts is used for a variety of purposes, such as displaying a three-dimensional image of the static bite relationship of a particular patient for diagnostic and teaching purposes, or creating similar study casts in a suitable fabrication device based upon the scan data. Using the teachings from U.S. Pat. No. 6,217,34, individual objects can also be scanned for displaying a three-dimensional image of the objects or for use in fabricating similar objects based upon the scan data.  
           [0004]    Scanning can also be used to verify a mating relationship between mating housing parts, such as housing parts for electronic devices including cellular telephones and electronic organizers. When housing parts are scanned, the scan data can be used to display three-dimensional images of the parts, with the displayed images being electronically brought together and displayed as a three-dimensional image, from which the accuracy of the fit between the housing parts can be determined.  
           [0005]    Although scanning of objects is previously known, extensive human operator interaction is typically required in conventional scanning processes to monitor the process. For example, an operator typically must be present to load as well as unload the object(s) to be scanned onto and from the scanner. The need for human interaction in the scanning process creates problems. If the object is not loaded properly onto the scanner by the operator, inaccurate scan data can result. Further, the presence of an operator adds a labor cost to the scanning process, thereby increasing overall costs. Costs are increased even further if scanning is to be performed 24 hours a day, which is necessary for scanning large numbers of objects. In this case, additional employees must be hired for second and third shifts in order to operate and monitor the scanner.  
           [0006]    Therefore, there is a need for an automated scanning system and method which reduces or eliminates the need for operator interaction, thereby facilitating mass scanning operations, improving the accuracy of the scan data and reducing the costs associated with the scanning operation.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention provides a system and method for mass, automated scanning of objects, including dental study casts, housing parts, and other objects. The system and method are able to function with little or no human operator intervention, thereby facilitating high volume, automated scanning and reducing scanning costs.  
           [0008]    In one aspect of the invention, a scanning system is provided. The system comprises a scanner having a scanning table, a conveyor mechanism adjacent the scanner for delivering an object to be scanned to the scanner, and a pick and place mechanism for taking the object from the conveyor mechanism and mounting it on the scanning table of the scanner.  
           [0009]    In yet another aspect of the invention, a method of scanning of objects by a scanner having a scanning table is provided. The method comprises conveying one or more objects to be scanned to the scanner using a conveyor mechanism; picking an object from the conveyor mechanism and mounting the object on the scanning table of the scanner; scanning the object; and removing the scanned object from the scanning table and delivering the scanned object to a discharge location.  
           [0010]    In still another aspect of the invention, a system for mass, automated scanning of dental study casts is provided. The system comprises a scanner having a scanning table, and a plurality of cassettes, each of which has a maxilla and mandible study cast for a single patient mounted thereon in known positions relative to each another. The system also includes a conveyor adjacent the scanner for delivering the cassettes to the scanner; and a pick and place mechanism engageable with the cassettes for picking one of the cassettes from the conveyor and mounting the picked cassette on the scanning table.  
           [0011]    These and various other advantages and features of novelty which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages and objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying description, in which there is described a preferred embodiment of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    Referring to the drawings, wherein like numerals represent like parts throughout the several views:  
         [0013]    [0013]FIG. 1 illustrates the method steps used to practice the principles of the present invention.  
         [0014]    [0014]FIG. 2 diagrammatically illustrates functional blocks associated with the scanning process and processing data from the scanner.  
         [0015]    [0015]FIG. 3 is a perspective view of an automated scanning system according to the present invention.  
         [0016]    [0016]FIG. 4 illustrates a portion of the scanner and the infeed conveyor.  
         [0017]    [0017]FIG. 5 is a perspective view of the rotary table of the scanner.  
         [0018]    [0018]FIG. 6 illustrates an exemplary tool used to implement the automated scanning system and method according to a preferred embodiment of the present invention.  
         [0019]    [0019]FIG. 7 illustrates a cassette used with the tool of FIG. 6.  
         [0020]    [0020]FIG. 8 illustrates a calibration procedure for determining reference points.  
         [0021]    [0021]FIG. 9 schematically illustrates the use of the tool and cassette in FIGS. 6 and 7.  
         [0022]    [0022]FIG. 10 schematically illustrates a pair of housing shells that can be scanned in order to verify their mating relationship. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]    A detailed discussion of a preferred embodiment of the automated scanning system and method of the present invention will be deferred pending a discussion of the concepts of the invention.  
         [0024]    1. Overview  
         [0025]    Referring first to FIG. 1, the overall method of the present invention is illustrated, and is designated generally by the numeral  10 . First, at block  12 , the object(s) to be scanned is fixedly mounted onto a cassette. Any object(s) which one finds desirable to scan can be mounted onto the cassette. Examples of suitable objects include dental study casts and mating housing parts for electronic devices such as cell phones and electronic organizers. The preferred embodiment will be described below with respect to scanning dental study casts. The cassette and the procedure for mounting dental study casts on the cassette are described below with respect to FIGS.  6 - 9 .  
         [0026]    At block  14 , the cassette is transported to the scanner by a suitable transport mechanism, and at block  16 , the cassette is picked from the transport by a picking mechanism and placed onto a table  32  of a scanner  30 . The transport mechanism and picking mechanism are described below and best seen in FIGS.  3 - 5 .  
         [0027]    Once the cassette is properly mounted, the object(s) is then scanned at block  18 . In the preferred embodiment described below, two dental study casts are mounted on the cassette and the data obtained from scanning the study casts is used to create and display study cast images. The scan data can also be used to fabricate replicas of the study casts in a fabrication device based upon the scan data. In the preferred embodiment, the scanner  30  is a laser scanner with a laser  31  that is capable of movements along x-y-z axes to permit scanning of the complex geometries of dental study casts. However, other scanning concepts can also be used to practice the system and methods described herein, such as digitizing scanning.  
         [0028]    Next, at block  20 , once the scan of the object(s) is complete, the cassette is removed from the scanner by the picking mechanism and placed onto a transport for subsequent transport away from the scanner. As described in the preferred embodiment below, the transport that conveys a scanned object(s) away from the scanner is preferably a transport mechanism that is separate from the transport mechanism that conveys the object(s) to the scanner. However, a single transport mechanism could be used to both convey the object(s) to and away from the scanner. It is also contemplated that instead of conveying the cassette away from the scanner after scanning, the cassette could be placed in a suitable discharge location for later removal.  
         [0029]    With reference to FIG. 2, the image data obtained from the scanner  30  is processed by processor  501  of a computer  500  to create the image(s) of the scanned object(s), which in the preferred embodiment is the dental study casts. The processing by the processor  501  may include converting the scan data into images for display on a video display unit  503 ; converting the scan data into CNC or other format of output for use by a fabrication device  507  (also known as a prototyping apparatus); storing the scan data in a memory location or device  504 ; and/or transmitting the scan data to a remote processor  505  via modem block  502 . A user input device  506  permits input commands to control operation of the scanner, as well as permits the input of information concerning the object(s) to be scanned.  
         [0030]    It will be appreciated by those of skill in the art that the computer  500  may be a personal computer (e.g., a Pentium based PC) or a special purpose computer. Further, the video display unit  503  may include any number of display devices such as cathode ray tubes, LCD displays, etc. Still further, the memory device  504  may include hard drives, floppy drives, magnetic tape, CD-ROM, random access memory, and readonly memory devices. Further, the modem  502  is illustrated to show a communications capability. Such capability may also be by way of a network, etc.  
         [0031]    Fabrication device  507  may be connected directly to the computer  500  or may be connected to the remote computer  505 . The fabrication device  507  may be any number of devices which can utilize computer generated data and create a threedimensional object from such data. One example of such a machine are the devices utilizing stereo lithography technology manufactured by 3-D Systems of Valencia, Calif. under the model designations SLA-250 and SLA-500. Another example is the device utilizing filament technology (fused deposition modeling) manufactured by Statasys Corporation of Minneapolis, Minn. under the model designation FDM1500.  
         [0032]    Further details on scanning, in the preferred embodiment, dental study casts and processing the image data can be found in U.S. Pat. Nos. 6,217,334, 6,206,693, and 6,200,135, which are incorporated herein by reference.  
         [0033]    2. Automated Scanning  
         [0034]    The preferred embodiment will now be discussed. In the preferred embodiment, a pair of dental study casts  250 ,  252  are mounted onto a cassette  100  for scanning by the scanner  30 . The study casts  250 ,  252  are three-dimensional models of a patient&#39;s maxilla (i.e. upper) and mandible (i.e. lower) sets of teeth, respectively. The specifics of creating dental study casts from impressions that are taken of a patient&#39;s teeth is well known in the art. See, for example, U.S. Pat. Nos. 6,217,334, 6,206,693, and 6,200,135.  
         [0035]    Turning now to FIGS.  3 - 5 , a system  50  to achieve automated scanning of the study casts is illustrated. Prior to explaining the system in detail, some of the difficulties that are faced in implementing automated scanning will be discussed. An automated scanning system should be able to operate with minimal or no operator input. This reduces the costs associated with scanning, and increases throughput of the system because the system is able to run essentially all the time, day and night, with minimal operator input.  
         [0036]    One of the primary factors in being able to implement automated scanning of dental study casts is the ability to achieve an accurate bite registration of the images that result from the scanned upper and lower study casts. Without some basis by which the computer is able to properly register the scanned images of the upper and lower casts, an accurate visual representation of the bite registration cannot be achieved. Therefore, a suitable method for achieving bite registration is needed. A bite registration method that is suitable for use with the automated scanning system  50  is described later in this specification, as well as in copending U.S. patent application Ser. No. 09/746,468, filed on Dec. 22, 2000.  
         [0037]    Returning now to FIGS.  3 - 5 , the automated scanning system  50  includes a scanning station  52  at which the study casts  250 ,  252  are scanned by the scanner  30 . The scanner  30  is preferably a laser scanner as discussed above. Alternatively, other scanning concepts can be used, such as a digitizing scanning. Regardless of the particular scanner that is utilized, the scanner  30  is capable of scanning both the upper and lower casts  250 ,  252 , with the scan data therefrom being processed by the computer  500  as discussed above. An operator input station  58  is provided that preferably includes a controller, such as the computer  500 , for controlling operation of the system  50 . The station  58  also preferably includes the display unit  503  and input device  506  for displaying system information and allowing operator inputs, such as system operation commands and patient data for each pair of study casts to be scanned.  
         [0038]    The system  50  further includes a conveyor mechanism  60  for transporting the cassettes  100  to and from the station  52 . The conveyor mechanism  60  includes an infeed conveyor  62  with a conveyor belt  63  upon which the cassettes  100  with the study casts  250 ,  252  mounted thereon are placed for subsequent feeding to the station  52 . The conveyor mechanism  60  further includes an outfeed conveyor  64  with a conveyor belt  65  that feeds the cassettes  100 , after scanning, to a downstream location for subsequent handling. Alternatively, the outfeed conveyor  64  could be eliminated, and the conveyor  62  extended past the station  52  so that the conveyor  62  acts both as the infeed conveyor and the outfeed conveyor. In addition, conveying mechanisms other than belts can be used.  
         [0039]    Each cassette  100  is picked by a pick and place mechanism  66 , best seen in FIGS. 3 and 4, from the infeed conveyor  62  and placed onto the table  32  of the scanner  30  where it is fixed in place for scanning. After scanning, the cassette  100  is removed from the table  32  by the pick and place mechanism  66  and placed onto the outfeed conveyor  64  for subsequent handling.  
         [0040]    The system  50  permits automated, mass scanning of dental study casts, as well as other objects. As long as the system  50  is able to correlate the scanned data from each pair of study casts with a particular patient, such as through operator input via the input station  58  or by system identification of patient identifying indicia on the cassettes  100  or study casts  250 ,  252 , the system is able to operate independently while performing its scanning and data collection functions, with little or no human operator interaction.  
         [0041]    With reference to FIGS. 3 and 4, it is seen that the scanner  30  is mounted on a support structure  70 , such as a table, located adjacent the conveyor mechanism  60 . An L-shaped support arm  72  of the scanner  30  extends upwardly from the support  70  and towards the conveyor mechanism  60 . A y-axis slide  74  is fixed on top of the support  70 , and a support  76  for the rotary table  32  is mounted on the y-axis slide  74  so as to movable along the y-axis. An actuator  78 , such as a reversible electric motor, is mounted to the slide  74  and is in driving engagement with the support  76  for actuating the support  74  along the y-axis. An actuator  80 , such as a reversible electric motor, is also mounted to the support  76  and is in driving engagement with the rotary table  32  for rotating the table  32  about a central axis X-X.  
         [0042]    An x-axis slide  82  is fixed to the overhanging portion of the support arm  72  to allow movement of the laser  31  along the x-axis. In addition, a z-axis slide  84  is mounted to the x-axis slide  82  to allow movement of the laser  31  along the z-axis. An actuator  86 , such as a reversible electric motor, is mounted to the x-axis slide  82  and is in driving engagement with the z-axis slide  84  for actuating the z-axis slide  84  along the x-axis. In addition, an actuator  88 , such as a reversible electric motor, is mounted to the z-axis slide  84  and is in driving engagement with a support arm  90  for actuating the support arm  90  along the z-axis. The support arm  90  forms part of the pick and place mechanism  66  and supports the laser  31 .  
         [0043]    Therefore, the laser  31  of the scanner  30  is mounted for linear movements along the x-axis slide  82  and the z-axis slide  84 . Further, the scanning table  32  is mounted for linear movement along the y-axis slide  74 , as well as for rotary movement about the axis X-X. The entire surface area of the study casts  250 ,  252  can thus be completely scanned through suitable movements of the laser  31  or the study casts  250 ,  252  along the x-y-z axes and about the X-X axis.  
         [0044]    [0044]FIG. 4 illustrates the details of the pick and place mechanism  66  that is used to pick a cassette  100  from the conveyor  62  and place the cassette  100  on the rotary table  32  for scanning of the study casts  250 ,  252 . The mechanism  66  is also used to remove the cassette from the rotary table and place it onto the conveyor  64 . The laser  31  is fixed to the support arm  90  of the pick and place mechanism  66  through a laser support  92 , whereby the laser  31  moves up and down along the z-axis when the arm  90  is actuated along the z-axis slide  84 . In addition, a cassette engagement finger  94  and a release finger  96  are fixed to the arm  90  at locations spaced from each other as shown in FIG. 4.  
         [0045]    The mechanism for fixedly mounting the cassette  100  onto the rotary table  32  will now be described with reference to FIG. 5. The rotary table  32  includes a face plate  102  on the top surface thereof. A stop  104 , a pin  106  and a spring loaded lever arm  108  are all disposed on top of the face plate  102  for interacting with the cassette  100  and retaining the cassette  100  on the rotary table  32 .  
         [0046]    The stop  104  includes a beveled surface  110  (also seen in FIG. 4) that is designed to engage a beveled edge  112  of the cassette  100 . The pin  106  is positioned to interact with a notch  114  that is formed in the side of the cassette  100  and counteract a rotational force that is applied to the cassette  100  by the lever arm  108 . The lever arm  108  includes a pivot post  116  that is pivotally mounted on the face plate  102  directly opposite the stop  104 . The post  116  is resiliently biased by a spring or other suitable resilient means in order to provide a force F in the direction of the arrow against the cassette  100  thereby forcing the cassette  100  against the stop  104  and the pin  106 . A tooling ball  118  is fixed to the lever arm  108  directly opposite the pin  106 , and engages a beveled edge  120  on the cassette  100 .  
         [0047]    When the cassette  100  is disposed on the face plate  102 , the force provided by the lever arm  108  pushes the cassette  100  against the stop  104  and the pin  106 . Further, the engagement between the beveled surface  110  of the stop and the beveled edge  112 , as well as between the tooling ball  118  and the beveled edge  120 , create a downward force that presses the cassette downward against the face plate, firmly holding the cassette in place for subsequent scanning. The pin  106 , because it is located directly opposite the tooling ball  118 , counteracts any tendency for the cassette  100  to rotate about the stop  104  as a result of the force F applied by the lever arm  108 .  
         [0048]    The procedure for picking a cassette from the conveyor  62  and placing it onto the rotary table  32  using the pick and place mechanism  66  will now be described with reference to FIGS. 4 and 5. The cassette  100  is formed with a key hole slot  130  (shown in dashed lines in FIG. 4) proximate the center thereof and extending generally parallel to the x-axis slide  82 . The cassette engagement finger  94  of the pick and place mechanism  66  includes a male tab  132  that has a shape that is complimentary to the slot  130 . The finger  94  further includes tab  134  that engages the exterior of the cassette when the male tab  132  is within the slot  130 . It is further evident from FIG. 4 that the removal finger  96 , which is intended to engage the lever arm  108  and remove the bias force F, projects a distance below the male tab  132  for a purpose which will become evident.  
         [0049]    In order to pick a cassette  100  from the conveyor  62 , the z-axis slide  84  is actuated along the x-axis (i.e. to the left in FIG. 4) so that the finger  94  is positioned over the slot  130 . The arm  90  is then actuated along the z-axis (i.e. downward in FIG. 4) so that the male tab  132  enters the slot  130 . The z-axis slide  84  is then once again moved to the left to lock the male tab  132  in the slot  130 , with the tab  134  engaging the exterior surface of the cassette  100  for stabilization purposes. The arm  90  is then lifted upward, thereby lifting the cassette  100  off of the conveyor  62 . The z-axis slide  84  is then actuated to the right to bring the cassette to a position above the rotary table  32 . The arm  90  is then lowered until the removal finger  96  is next to the inside surface of the lever arm  108 , between the post  116  and the tooling ball  118 . Then, by moving the z-axis slide  84  to the left, the finger  96  forces the lever arm  108  in the opposite direction about the post  116 . The cassette  100  can then be lowered onto the face plate  102  by lowering the arm  90  further. Once the cassette  100  is fully lowered, the z-axis slide  84  is moved slightly to the right and the arm  90  is then raised, thereby removing the male tab  132  from the slot  130 . As this occurs, the finger  96  disengages from the lever arm  108 , and the biasing force F of the lever arm forces the cassette against the stop  104  and the pin  106 , thereby firmly retaining the cassette on the rotary table for subsequent scanning.  
         [0050]    Removal of the cassette  100  from the rotary table  32  after scanning occurs in a similar fashion to the mounting of the cassette. The finger  96  removes the force of the lever arm  108  as the male tab  132  is being locked into the slot  130 . When the lever arm  108  has been moved sufficiently and the male tab  132  is firmly secured in the slot  130 , the cassette  100  can be moved slightly to the left and lifted upward, thereby removing the cassette. The cassette  100  is then carried to the conveyor  64 , or other suitable discharge location, for conveyance away from the scanner  30 .  
         [0051]    It is to be realized that the x-axis slide  82  and the arm  90  must be of sufficient dimensions so as to be able to reach the two conveyors  62 ,  64 . When side-by-side conveyors  62 ,  64  are used, as illustrated in FIG. 3, the x-axis dimensions of the x-axis slide  82  and the arm  90  are generally increased. For the case of a conveyor  62  that is used as both the infeed and the outfeed, the x-axis dimensions of the x-axis slide  82  and the arm  90  need not be as large.  
         [0052]    As was described above, a suitable method for achieving an accurate bite registration of the images that result from the scanned study casts  250 ,  252  is needed. FIGS.  6 - 9  illustrate one embodiment of how an accurate bite registration can be achieved. This method can be used with study casts  250 ,  252  that have roughly formed (i.e. not machined to precise geometric specifications) bases. In this method, the study casts  250 ,  252  are initially mounted on the cassette  100  in known locations relative to each other, prior to placement of the cassette  100  onto the conveyor  62  for conveyance to the scanner  30 . Because the positioning of each study cast relative to the other is known, once scanning is complete, the scanned images can be brought into registration using predetermined reference points.  
         [0053]    FIGS.  6 - 9  illustrate the tooling and other apparatus used to implement this method. FIG. 6 illustrates a tool  256  that is provided with a precision vertical slide  258  that is mounted so as to move vertically up and down relative to the tool  256 . The tool  256  includes a base  260  and a vertical support  262  provided with a guide rail  264 . The slide  258  includes a base  266  that is slidable on the rail  264  and an arm  268  that overhangs the base  260 . The arm  268  includes a pair of locating holes  270 ,  272  on the bottom surface of the arm  268  facing the base  260 . In addition, the base  260  includes a pair of locating pins  274 ,  276 .  
         [0054]    [0054]FIG. 7 illustrates the cassette  100  upon which the study casts  250 ,  252  are to be mounted. The study cast  252  is schematically illustrated in position on the cassette  100 . The cassette  100  includes a ridge  278  that separates the cassette into two halves, the first half receiving the study cast  252  and the second half receiving the study cast  250 . A removable plate  280 , upon which the study cast  250  is to be mounted, is provided on the second half of the cassette  100 . A pair of locating holes  274 ′,  276 ′ are formed in the bottom of the cassette  100  which interact with the locating pins  274 ,  276 , respectively, so as to permit mounting of the cassette onto the base  260  of the tool  256 . In addition, the removable plate  280  includes a pair of locating pins  270 ′,  272 ′ formed on the bottom thereof that are designed to fit within the locating holes  270 ,  272 , respectively, on the arm  268  of the slide  258 . The second half of the cassette  100  includes holes (not visible) that receive the locating pins  270 ′,  272 ′ when the plate  280  is disposed on the cassette.  
         [0055]    With reference to FIG. 9, in implementing this method, the study cast  252  is first fixed onto the first half of the cassette  100  such as by using hot melt glue or other suitable temporary fastening means. The cassette  100  is then mounted onto the base  260  of the tool  256  via the locating pins  274 ,  276  and locating holes  274 ′,  276 ′, with the study cast  252  disposed underneath the arm  268  of the slide  258 .  
         [0056]    A wax wafer  282 , or other similar impression material, which has been previously bit into by the patient corresponding to the study casts  250 ,  252  to record the patient&#39;s bite registration, is then placed onto the study cast  252 . The wafer  282  is placed onto the study cast so that the impression that corresponds to study cast  252  fits onto the teeth of the cast  252 . The study cast  250  is then placed on top of the wafer  282  with the teeth fitting into their corresponding impressions in the wafer. It should be realized that the wafer  282  permits the study casts  250 ,  252  to be registered with each other while on the tool  256 . Once the study casts are registered, the plate  280  is fixed onto the bottom surface of the study cast  250  such as by using hot melt glue or other fixing means.  
         [0057]    The slide  258  is then slid downward, either manually using a knob  284  fixed to the arm  268  or through suitable mechanical means (not illustrated), toward the plate  280 . The arm  268  then captures the plate  280 , with the locating pins  270 ′,  272 ′ fitting into the locating holes  270 ,  272 . A fastener  286  connected to the plate  280  extends upwardly through a hole provided in the arm  268  to permit the plate  280 , and the study cast  250  now fixed thereto, to be fixed to the arm  268  so when the slide  256  is again raised, the study cast  250  and plate  280  are raised with the slide  256 . Raising the slide  256  separates the study casts  250 ,  252  while precisely maintaining the relative positioning of the study casts so that the registration is maintained.  
         [0058]    After the slide  258  is raised, the plate  280 , with the study cast  250  fixed thereto, is removed from the arm  268 , flipped over so that the study cast  250  faces upward, and mounted onto the second half of the cassette  100  so that both study casts are now fixed on the cassette. The cassette can then be placed onto the conveyor  62  for transport to the scanner so that the study casts can be scanned to create scanned images. It should be realized that the study casts are mounted on the cassette  100  in positions that maintain the bite registration of the patient. However, what is also needed are reference points so that the images resulting from the scan can be aligned.  
         [0059]    Reference points are used in this method to achieve alignment, with the reference points being determined in accordance with a calibration process illustrated in FIG. 8. The calibration process is performed prior to mounting the study casts on the cassette. To perform calibration, the cassette  100  is provided with a removable plate  290 , in place of the plate  280 . The plate  290  includes a plurality of tooling balls  292  thereon. In the preferred embodiment, three tooling balls  292  are used, however a larger number of tooling balls could also be used. A layer of clay  294  or other impression material is placed on the other half of the cassette  100 . The cassette  100  is then mounted on the tool  256  as discussed above, with the clay  294  located underneath the arm  268 , and the plate  290  is mounted on the arm  268  with the tooling balls  292  facing downward toward the clay  294 . The slide  258  is then moved downward until the balls  292  move into the clay  294  in order to form tooling ball impressions  296 . The slide  258  is then moved upwardly and the plate  290  removed therefrom and remounted onto the cassette  100 .  
         [0060]    The cassette  100  is then mounted onto the rotary table  32  of the scanner  30 , as discussed above, and the scanner scans the tooling balls  292  and the impressions  296 . Mounting of the cassette can be done using the pick and place mechanism  66 , or manually. By scanning the tooling balls  292  and impressions  296 , the computer  500  can find the centers of the balls  292  and impressions  296 , with the centers providing fixed reference points for use in aligning subsequently scanned study casts. These fixed reference points are retained within the memory device  504 , so that the computer  500  knows ahead of time the reference points to be used. Due to the construction of the tool  256  and the cassette  100 , the relative positions of the centers of the tooling balls  282  and the centers of the impressions  296  correspond to identical positions on the study casts  250 ,  252 . Therefore, once the images of the study casts are generated, the three fixed points can be aligned to register the scanned impressions. After the points are aligned, the scanned images can be brought together by the computer  500  to a position representative of the patient&#39;s actual bite registration. The reference points are fixed in system memory, so that once the study casts are properly positioned on the cassette  100 , the scanning and registration can be completed automatically by the computer  500 , without requiring further operator input. It is further contemplated that the use of the tool  256  and the related process of positioning the study casts on the cassette  100  can be automated as well.  
         [0061]    Periodically, the calibration process should be repeated so as to obtain updated reference points. This is necessary due to loosening of tolerances and general degradation of equipment.  
         [0062]    As part of the automation of scanning, the system  50  needs to know which of the study casts  250 ,  252  being scanned belong to which patient, so that the scan data can be saved to the appropriate memory location belonging to that patient in the memory device  504 . To accomplish this objective, the cassette  100  can be provided with a patient identification tag  150 , such as a radio frequency tag, a bar code or other suitable means. The tag  150  can contain patient data such as the patient&#39;s name and address, as well as more extensive patient data pertaining to the patient&#39;s past medical history, such as previous dental procedures. A sensor  152  is provided at a suitable location, such as on the support  76  as shown in FIG. 3, to read the tag  150 . The sensor  152 , as is shown in FIG. 2, is connected to the central processor  501  of the computer so that the information that is read from the tag  150  is provided to the computer. The sensor  152  can be located at any convenient point in the system  50 , such as on the tool  256  as shown in FIG. 6. However, it is preferred that the sensor  152  be positioned at a location so that it performs a read of the tag  150  just prior to, or immediately after, scanning of the study casts  250 ,  252 .  
         [0063]    The preferred embodiment of the invention has been described in relation to automated scanning of dental study casts. However, as discussed above, the concepts described herein can also be used in implementing automated scanning of a variety of other objects as well. For instance, automated scanning can be applied to parts that are to be mated together, such as molded housing shells for cellular phones, electronic organizers, pacemakers, and a host of other parts having complex geometries. When applied to mated parts, the accuracy of the parts, and the molds used to create the parts, can be verified by scanning the parts and determining from the scanned images whether a suitable fit between the parts will be achieved. This verification can be performed at the manufacturing level by the supplier of the molded parts as the molded parts are molded, or at an assembly level by the user of the molded parts to ensure the quality of received parts. Molded parts can include plastic molded parts, metal parts formed by metal molding techniques, and mating parts formed from other materials and other molding techniques suitable for those other materials.  
         [0064]    [0064]FIG. 10 illustrates a pair of housing shells  300 ,  302  that are to be mated together to form a housing for a device such as a cellular phone, electronic organizer or a pacemaker. The inside of each housing shell  300 ,  302  is schematically illustrated to show an example of the possible complex geometry inside each shell. In use, the shell  300  is flipped over and mated with the shell  302  to enclose the electronics and other components of the device formed by the mated shells  300 ,  302 . The shells  300 ,  302  can be scanned and images created from the scan data in order to display the mating relationship (i.e. “verify” the parts) to determine whether the shells fit together adequately. A plurality of reference points would have to be used to achieve alignment of the shell images once they are scanned. For instance, three points R, S, T on the shell  300 , and three points R′, S′, T′ on the shell  302 , corresponding to, for example, mounting posts on the shells  300 ,  302 , could be used to align the images once the shells are scanned. The method described above for registering the dental study casts could also be used to register the shells  300 ,  302 .  
         [0065]    In addition, automated scanning can be applied to single objects that are not mated or fitted with a corresponding object. For instance, single objects can be scanned for subsequent display of an image of the object created from the scan data, or the scan data can be used to fabricate a replica of the object based upon the scan data.  
         [0066]    While a particular embodiment of the invention has been described, it will be understood that by those skilled in the art that the invention is not limited by the application, embodiment or the particular devices disclosed and described herein. It will be appreciated that other devices that embody the principles of this invention and other applications therefor other than as described herein can be configured within the spirit and intent of this invention. The system described herein is provided as only one example of an embodiment that incorporates and practices the principles of this invention. Other modifications and alterations are well within the knowledge of those skilled in the art and are to be included within the broad scope of the appended claims.  
         [0067]    The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.