Abstract:
The present invention relates to novel automated inspection systems and related methods of use. In particular, the present invention provides an automated threaded fastener inspection system, and related methods of use. Furthermore, the present invention provides systems and methods for identifying damaged threaded fasteners prior to industrial use.

Description:
[0001]     This is a Continuation-In-Part of U.S. patent application Ser. No. 10/698,045, filed Oct. 30, 2003 and entitled Method of Inspecting Threaded Fasteners and a System Therefor. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to automated inspection systems and methods of inspection. In particular, the present invention provides a threaded fastener inspection system, and related inspection methods. Furthermore, the present invention provides systems and methods for identifying damaged threaded fasteners prior to their industrial use.  
       BACKGROUND  
       [0003]     Threaded fasteners are used for many applications and must be transported during manufacture and use. During transit and processing, threaded fasteners may become damaged. For example, within a large batch of threaded fasteners, a small number of threaded fasteners may suffer thread damage as they come into contact with other fasteners or with handling equipment. The use of damaged threaded fasteners can result in a defective and potentially unsafe product.  
         [0004]     Damaged threaded fasteners are particularly costly for automobile manufacturers. Assembly of automobile engines relies upon threaded fasteners to seal critical engine components. The use of damaged threaded fasteners can result in an improperly sealed engine that is prone to fluid leaks. Automobile manufacturers and suppliers implement post production inspection equipment to locate defective parts such as threaded fasteners. However, post production removal of fasteners is expensive as the engine may need to be disassembled and reassembled. As such, it is desirable to locate defective fasteners prior to assembly.  
         [0005]     One inspection technique currently used is a manual inspection of each threaded fastener prior to its use within part assembly. This technique suffers from many problems. Notably, this technique is very expensive, slow, and suffers from human error.  
         [0006]     A second inspection technique currently used involves the use of a camera to photograph the threads of a threaded fastener. One problem with this approach is that the camera is unable to capture the entire thread of the threaded fastener. Only a single profile is generally observed. If a thread defect is oriented away from the photographic range of the camera, it will remain undetected.  
         [0007]     Accordingly, what is needed in the art are systems and methods for identifying damaged threaded fasteners prior to incorporation into an assembled product.  
       SUMMARY  
       [0008]     The present invention relates to automated inspection systems and methods of inspection. In particular, the present invention provides a threaded fastener inspection system, and related inspection methods. Furthermore, the present invention provides systems and methods for identifying damaged threaded fasteners prior to their industrial use.  
         [0009]     Accordingly, the present invention provides a threaded fastener inspection system. In preferred embodiments the threaded fastener inspection system comprises a conveyor, at least one imaging device, and a computer processor. In some embodiments, the imaging device images threaded fasteners at a plurality of views during rotation of a threaded fastener along the conveyor. In further embodiments, the computer processor interfaces with the imaging device. In further embodiments, the computer processor is programmed to analyze the major and minor diameters of the threaded fastener at said plurality of views and compare said major and minor diameters to predetermined values to detect threaded fastener damage.  
         [0010]     In further preferred embodiments, the conveyor comprises a rail and a belt. In some embodiments, a portion of said belt is aligned along the length of the rail so that threaded fasteners are secured between the belt and the rail and so that movement of the belt results in the rotation of a threaded fastener along the rail. In preferred embodiments, the rail is a spring loaded rail.  
         [0011]     In other preferred embodiments, the imaging device captures an image of threaded fasteners for each 30 degree rotation a threaded fastener makes as it travels within the range of view of the imaging device. In preferred embodiments, the imaging device is stationary.  
         [0012]     In some preferred embodiments, the conveyor further comprises a distal end and a sorter, wherein the sorter is positioned at the distal end of the conveyor and wherein the sorter is activated when the computer processor identifies a defective threaded fastener so that damaged threaded fasteners are sorted from undamaged threaded fasteners. In further embodiments, the sorter is a trapdoor. In even further embodiments, the threaded fasteners identified as damaged are discarded into the sorter. In further preferred embodiments, an illumination device is oriented opposite of the imaging device.  
         [0013]     The present invention further provides a method of identifying damaged threaded fasteners, comprising providing threaded fasteners, rotating said threaded fasteners, imaging the threaded fasteners at a plurality of views during the rotation, determining major and minor diameters of the threaded fasteners at the plurality of views, comparing the major and minor diameters to predetermined values to determine if the threaded fasteners are damaged, and sorting damaged threaded fasteners from undamaged threaded fasteners. In further embodiments, the comparing is performed by a computer processor.  
         [0014]     In even further embodiments, the threaded fasteners are rotated on a conveyor. In still further embodiments, the imaging is performed by a digital camera. In some embodiments, the at least one imaging device captures an image of the threaded fasteners for each 30 degrees of rotation a threaded fastener undergoes as said threaded fastener travels within the range of view of said at least one imaging device. In further embodiments, six views are captured.  
         [0015]     In other preferred embodiments, the present invention provides a threaded fastener inspection system comprising a light source, a light shield, a reflector having a sleeve therein for receiving a threaded fastener having a head, and an imaging device positioned to capture a back-lit image of the threaded fastener head. In further embodiments, the sleeve supports the threaded fastener head over the reflector, and the light shield and the reflector are positioned to direct light from the light source so that the threaded fastener head is back-lit. In further embodiments, the light source comprises a circular array of light emitting diodes. In further embodiments, the circular array of light emitting diodes is positioned over the light shield so that the threaded fastener head is shielded from being substantially directly illuminated by the circular array of light emitting diodes. In other embodiments, the light shield is conical in shape. In preferred embodiments, the reflector is formed from a polymeric material. In further embodiments, the reflector comprises Delran.  
         [0016]     In even further embodiments, the system further comprises a plurality of said reflectors. In further embodiments, the plurality of reflectors are arranged in a rotating tray. In preferred embodiments, the light source and the light shield are movably mounted so that the light shield and the light source can be raised and lowered over the reflector. In further embodiments, the imaging device is a digital camera. In even further embodiments, the imaging device comprises a processor. In preferred embodiments, the processor is configured to analyze images captured by the digital camera. In yet further embodiments, the system further comprises a thread damage inspection system.  
         [0017]     The present invention further provides a method of identifying damaged threaded fasteners comprising providing at least one threaded fastener having a head and an imaging device, back-lighting said head of the threaded fastener, producing a back-lit image of the head of the threaded fastener, and analyzing the back-lit image of the head of the threaded fastener to detect damaged threaded fastener heads. In further embodiments, the method further comprises the step of sorting damaged threaded fastener heads from non-damaged threaded fastener heads. In preferred embodiments, the imaging device is a digital camera. In further preferred embodiments, the imaging device comprises a processor. In preferred embodiments, the processor is configured to identify the center of the head of the threaded fastener, measure a plurality of radii from the center, and compare the measurements to pre-determined values to identify damaged threaded fastener heads. In further embodiments, the processor is further configured to compare an overlapping series of averaged radii measurements to pre-determined values to identify damaged threaded fastener heads.  
         [0018]     Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features.  
     
    
     FIGURE DESCRIPTION  
       [0019]      FIG. 1A  illustrates an undamaged threaded fastener and  FIG. 1B  illustrates a damaged threaded fastener.  
         [0020]      FIG. 2  illustrates a threaded fastener thread damage inspection system.  
         [0021]      FIG. 3  illustrates a threaded fastener in the threaded fastener thread damage inspection system of  FIG. 2 .  
         [0022]      FIG. 4  illustrates the inspection area of the threaded fastener thread damage inspection system.  
         [0023]      FIG. 5A -F illustrate the range of view of an imaging device within the threaded fastener thread damage inspection system.  
         [0024]      FIG. 6  illustrates a threaded fastener head inspection system.  
         [0025]      FIG. 7  illustrates a threaded fastener head top image generated with the present invention.  
         [0026]      FIG. 8  schematically illustrates a threaded fastener inspection system. 
     
    
       [0027]     Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof.  
       DETAILED DESCRIPTION  
       [0028]     The present invention provides inspection systems and methods. The illustrated and preferred embodiments discuss these techniques in the context of threaded fastener inspection systems and methods. However, it should be appreciated that the invention is applicable for use in other inspection applications.  
         [0029]     The threaded fastener inspection systems and methods of the present invention have numerous advantages over previous prior art devices including, but not limited to, a faster and more precise approach toward assessing threaded fastener damage.  FIGS. 1-8  show various preferred embodiments of the threaded fastener inspection systems and methods of the present invention. The present invention is not limited to these particular embodiments.  
         [0000]     Threaded Fastener Inspection Systems and Methods  
         [0030]     In some embodiments, the present invention provides systems and methods for detecting thread damage within threaded fasteners. Threaded fasteners refer to hardware agents comprising a threaded face and a head. Examples include, but are not limited to, threaded workpieces, nuts, screws, set screws, grub screws, threaded bolts, and the like.  
         [0031]      FIG. 1  generally illustrates an undamaged threaded fastener  10  and a damaged threaded fastener  15 . A threaded fastener thread face generally comprises a continuous helical ridge  20  formed on the inside (nut) or outside (screw) of a cylinder  25 . The apex of the ridge  20  is called the crest  30 . Between each crest is a space, called the root  35 . Threads are set at an angle to the axis  40  of the bolt or nut. This slope is called the helix angle  45 . The helix angle  45  must be sloped, either to the right (for right-hand threaded screws) or the left (for left-hand threaded screws). The threads on a threaded fastener further comprise a major diameter  50  and a minor diameter  55 . The major diameter  60  refers to the outside diameter of the thread face and is measured from the outer edge of the crest  30 . The minor diameter  55  refers to the inside diameter of the thread face and is measured from the outer edge of the root  35 . An undamaged threaded fastener  10  has predetermined or default undamaged major diameter  50  and minor diameter  55  distances. A threaded fastener with damaged threads will have major diameter  50  and minor diameter  55  distances inconsistent with the default undamaged major diameter  50  and minor diameter  55  distances. Referring to  FIG. 1 , the damaged threaded fastener  55  has a blemish  60  (e.g., a nick or a strip in the thread face) within the thread face. The blemish  60  results in a major diameter  50  distance inconsistent with the undamaged threaded fastener  10  major diameter  50  distance.  
         [0032]     The present invention provides systems and methods wherein threaded fasteners are rotatably transported during inspection. Rotatable transport of a threaded fastener refers to rotation of the threaded face along a surface (e.g., rail) resulting in the movement of the threaded fastener along the surface. The thread face may be rotated clockwise or counterclockwise depending on the desired direction of transport. Rotatable transport of a threaded fastener is not limited to a particular speed of transport. In addition, a threaded fastener may be rotatably transported such that the threaded fastener is positioned above, below, or along the direction of transport.  
         [0033]      FIG. 2  illustrates an inspection system  100  of the present invention. In preferred embodiments, the inspection system  100  comprises a conveyor  105 , an inspection area  110 , a computer processor  115 , and a sorter  120 .  
         [0034]     The conveyor  105  of the present invention rotatably transports threaded fasteners. A conveyor  105  may be driven automatically or manually. In preferred embodiments, the conveyor  105  is driven by an electric motor  145 . In some embodiments, the conveyor  105  is positioned at an incline from the conveyor proximal end  125  to the conveyor distal end  130 . The conveyor  105  may operate at any desired speed of transport. The conveyor  105  is not limited to a particular length. In preferred embodiments, the conveyor  105  comprises a rail  135  and a belt  140 .  
         [0035]     In preferred embodiments, the rail  135  comprises any type of material (e.g., steel, metal, plastic, wood) or mixture of such materials. The rail  135  is not limited to a particular length or width. In preferred embodiments, the width of the rail  135  is small in comparison to the length of the threaded fastener so that only a small portion of the face of the threaded fastener is obscured by the rail  135 .  
         [0036]     In preferred embodiments, the rail  135  is a spring loaded rail  175 . In some embodiments, the spring loaded rail  175  comprises at least one spring  180  and  185 . In some embodiments, the spring  180  is positioned around a cylinder  200 . The cylinder  200  can comprise any type of material (e.g., metal, plastic) or any mixture of such materials. The cylinder  200  is not limited by a particular length or width. The springs  180  and  185  may be adjusted to create a desired tension. In preferred embodiments, the spring loaded rail  175  contains two springs  180  and  185 . In further embodiments, the two springs  180  and  185  are positioned at the proximal end  190  and the distal end  195  of the spring loaded rail  175 . In even further embodiments, the two springs  180  and  185  are positioned across from rollers  150  positioned at the proximal and distal ends of the belt  140 .  
         [0037]     The belt  140  can preferably comprise any type of material (e.g., rubber, metal, leather, plastic) or mixture of such materials. The belt  140  may be driven automatically or manually. In preferred embodiments, the belt  140  is driven by a motor  145 . The belt  140  is not limited to a particular length or width. In preferred embodiments, the belt  140  is approximately ¼ inch thick. In some embodiments, a fixed shape is maintained in the belt  140  through a plurality of rollers  150 . In preferred embodiments, rollers  150  are positioned at the belt proximal end  155  and the belt distal end  160  of the belt  140 .  
         [0038]     In preferred embodiments, threaded fasteners  136  are rotatably transported between the rail  135  and the belt  140 . The belt  140  is positioned along the rail  135 . A threaded fastener  136  enters the conveyor  105  at the proximal end  165  of the rail  135 . In some embodiments, the proximal end  165  of the rail  135  is rounded  170  to facilitate the entrance of threaded fastener  136  between the rail  135  and the belt  140 .  
         [0039]      FIG. 3  illustrates a threaded fastener between the rail  135  and the belt  140 . The upper end of the threaded fastener thread face is positioned between the rail  135  and the belt  140 . The head of the threaded fastener is positioned above the rail  135  and the belt  140 . The movement of the belt  140  results in the threaded fastener transporting along the rail  135 . Alternatively, the head of the threaded fastener can ride on a pair of spaced apart rails with the belt  140  being located beneath one of the rails.  
         [0040]     Returning to  FIG. 2 , the inspection area  110  comprises an imaging device  205  and an illumination device  210 . The imaging device  205  (e.g., digital camera) may further be positioned anywhere along the length of the rail  135 . The imaging device  205  may be held in a stationary position or may be mobile. In preferred embodiments, the imaging device  205  is stationary. The present invention is not limited to any particular type of imaging device  205 . Furthermore, the imaging device  205  may be adjusted to accommodate imaging of threaded fasteners of various sizes and shapes.  
         [0041]     The inspection area  110  further comprises an illumination device  215  (e.g., light bulb). The illumination device  215  is not limited to any particular strength (e.g., wattage). In some embodiments, the illumination device  215  is positioned beneath the belt  140  so that a threaded fastener traveling along the conveyor  105  is back-lit. The illumination device  215  is further positioned directly across from the imaging device  205 .  
         [0042]      FIG. 4  illustrates a threaded fastener within an inspection area  110 . An imaging device  205  (e.g., digital camera) is positioned below the rail  135 . In preferred embodiments, the imaging device  205  is positioned so that the upper end of the imaging device lens  210  is positioned in line with the lowest point of the rail  135 . As discussed above, a threaded fastener positioned between the rail  135  and belt  140  will have the majority of its threaded face exposed beneath the rail  135  and belt  140 . The imaging device lens  210  is further positioned so as to be within view of the entire exposed threaded face of a threaded fastener positioned between the rail  135  and belt  140 .  
         [0043]     The present invention is configured to image the thread face of a threaded fastener traveling along the rail  135 . In preferred embodiments, a rotating threaded fastener passing within the range of view of the imaging device  205  will expose at least half (e.g., 180 degrees) of its face to the imaging device lens  210 . It will be recognized that the speed of the motor  145  can be varied to vary the speed of the belt  140  and thus the speed of rotation of the threaded fastener. The imaging device  205  is configured to capture a plurality of images of the thread face of a threaded fastener rotating along the rail  135 . In preferred embodiments, the imaging device  205  is programmed according to this speed of rotation so that it can capture an image of the threaded fastener for each 30 degree rotation the threaded makes as it travels within the range of view of the imaging device lens  210 . As illustrated in  FIG. 5 , in preferred embodiments the imaging device  205  captures images of the entire (e.g., 360 degree) face of a rotating object if six images are compiled of the rotating object at six successive 30 degree intervals. In addition, six images of a rotating object taken at six successive 30 degree increments ensures that overlapping profiles of the face of the rotating object are captured.  
         [0044]     In preferred embodiments, the imaging device  205  is configured to capture six images of the thread face of a threaded fastener rotating along the rail  135 . In further preferred embodiments, the imaging device  205  is configured to capture six images of the thread face of a threaded fastener at six successive 30 degree intervals as the threaded fastener rotates along the rail  135 .  
         [0045]     In preferred embodiments, the imaging device  205  provides images of the thread face of a threaded fastener to the computer processor  115 . The present invention is not limited to any type of computer processor  115 . In some embodiments, the computer processor  115  is a part of the imaging device  205 , while in other embodiments, the computer processor  115  is interfaced with imaging device  205  via a computer cable. The computer processor  115  is programmed to detect damaged threaded fastener thread faces by analyzing the images obtained from the imaging device  205  and comparing the data obtained from this analysis with a set of predetermined threaded fastener face criteria. According to one aspect of the invention, the inspection system is looking for the absence of light. If light is present during the inspection process, the system recognizes that a flaw or defect may be present in the threaded fastener. According to another aspect of the invention, default major and minor diameters for undamaged fasteners are compared to the imaged major and minor diameters. Threaded fasteners not meeting the predetermined threaded fastener face criteria are sorted via a sorter  120 . In preferred embodiments, the sorter  120  is a trapdoor.  
         [0000]     II. Threaded Fastener Head Inspection Systems and Methods  
         [0046]     Threaded fasteners may be defective or damaged in numerous manners (e.g., cracked heads, unsealed heads, split heads, burrs). The threaded fastener inspection systems of the present invention also include systems for identifying damaged threaded fastener heads.  
         [0047]     Threaded fasteners are often coated to provide threaded fasteners with different colors. One method of inspecting threaded fastener heads involves directly illuminating and imaging threaded fastener heads followed by subsequent analysis of the acquired image. Such inspection systems, however, often report false positives and negatives due to varied light reflection caused by various colors of threaded fastener heads. The present invention solves this problem by producing a back-lit image of the threaded fastener head.  
         [0048]      FIG. 6  illustrates a threaded fastener head inspection system  500  of the present invention. In preferred embodiments, the threaded fastener head inspection system  500  comprises a reflector unit  505 , a light shield  510 , a light source  515 , and an imaging device  520 .  
         [0049]     Generally, the threaded fastener head inspection systems of the present invention image a threaded fastener head  525  with light reflected from a reflector unit  505 . In preferred embodiments, the light emitted from the light source  515  is directed onto a reflector upper surface  530 . In such embodiments, the light  535  emitted from the light source  515  is reflected off of the reflector upper surface  530  and directed to the threaded fastener head  525 . As such, the light source  515 , in conjunction with the reflector unit  505  and light shield  510 , generate a back-lit view (e.g., silhouette) of the threaded fastener head  525 . In some embodiments, the imaging device  520  is fixedly mounted over the light shield  510  and reflector unit  505 . In preferred embodiments, the imaging device  520  images the threaded fastener head  525  illuminated by the light source  515 . In some preferred embodiments, described in more detail below, a processor analyzes the image to identify the damaged threaded fastener heads  525 .  
         [0050]     Still referring to  FIG. 6 , the reflector unit  505  of the present invention positions the threaded fastener  540  for analysis and reflects light. In some embodiments, the reflector unit  505  comprises a reflector upper surface  530 . In some embodiments, the reflector upper surface  530  and reflector unit  505  have an opening therein. In some embodiments, a sleeve  545  is positioned in the opening. In some embodiments, the sleeve  545  is a cylinder into which a threaded fastener  540  can be inserted. In preferred embodiments, the diameter of the sleeve  545  is matched to the threaded portion of the threaded fastener so that when the threaded fastener  540  is inserted into the sleeve  545 , the threaded fastener head  525  is supported by the sleeve top lip  550 . In preferred embodiments, the entire or at least a substantial portion of the threaded fastener head  525  is exposed on the outside of the sleeve  545  and is thus available for imaging.  
         [0051]     In further preferred embodiments, the threaded fastener head inspection systems  500  of the present invention comprise a plurality of reflector units  505 . In even further preferred embodiments, the plurality of reflector units  505  are arranged in an indexed rotating tray.  
         [0052]     Still referring to  FIG. 6 , the reflector upper surface  530  serves to reflect light directed onto its surface area. The reflector upper surface  530  is not limited to a particular type of reflective material (e.g., steel, metal, mirror) or mixture of such materials. In preferred embodiments, the reflector unit  505  and reflector upper surface  530  comprises Delran. In other embodiments, the reflector upper surface  530  and the reflector unit  505  comprise different materials. The reflector upper surface  530  is not limited to a particular shape (e.g., oval, circular, square, rectangular). In preferred embodiments, the reflector upper surface  530  is circular. The reflector upper surface  530  is not limited to particular height or width. In preferred embodiments, the width of the reflector upper surface  530  is greater than the width of the threaded fastener head  525 .  
         [0053]     Still referring to  FIG. 6 , the light shield  510  comprises a light shield lower portion  555  and a light shield upper portion  560 . The light shield lower portion  555  is preferably sized to be the approximate diameter of the threaded fastener head  525 . The light shield lower portion  555  is not limited to a particular shape. In preferred embodiments, the shape of the light shield lower portion  555  is consistent with the shape of the threaded fastener head  525  (e.g., generally circular). The light shield lower portion  555  is not limited to a particular width. In preferred embodiments, the width of the light shield lower portion  555  is consistent with the width of the threaded fastener head  525 .  
         [0054]     The light shield upper portion  560  is not limited to a particular shape (e.g., oval, circular, square, rectangular). In preferred embodiments, the shape of the light shield upper portion  560  is consistent with the configuration of the light source  515 . The light shield upper portion  560  is not limited to a particular width. In preferred embodiments, the width of the light shield upper portion  560  is greater than the width of the light shield lower portion  555 .  
         [0055]     The light shield  510  is preferably sized to fit around a threaded fastener head  525  and prevent the threaded fastener head top  565  from being directly illuminated. The light shield  510  is not limited to a particular type of material (e.g., metal, wood, plastic, mirror) or mixture of such materials. In preferred embodiments, the light shield  510  is aluminum. The shield  510  is not limited to a particular height. In preferred embodiments, the height of the light shield  510  is larger than the height of the threaded fastener head  525 . The light shield  510  is not limited to a particular shape. In preferred embodiments, the light shield  510  is conical (e.g., funnel shaped).  
         [0056]     Still referring to  FIG. 6 , the light source  515  serves to illuminate the reflector upper surface  530  to back-light the threaded fastener head  525 . The light source  530  is not limited to a particular illumination source (e.g., infra red light source, black light source, regular light bulb). In some embodiments, the light source  515  comprises a plurality of light emitting diodes  570  (LEDs). In preferred embodiments, the LEDs  570  are arranged in a circular array. The present invention is not limited to a particular number (e.g., 1, 2, 3, 4, 8, 16, 100) of LEDs  570 . The present invention is not limited in the spacing of the LEDs  570  with respect to the light shield  510 . In preferred embodiments, the LEDs  570  are evenly spaced around the light shield  510 . The light source  515  is not limited to a particular brightness. In some embodiments, the light source  515  is positioned on the outside of the light shield  510 . The light source  515  is not limited to a particular location with respect to the light shield  510 . In preferred embodiments, the light source  510  is positioned on the outside of the light shield upper portion  560 . In some embodiments, the light source  515  and the light shield  510  are movably mounted so that the light source  515  and the light shield  510  can be moved between raised and lowered positions over the reflector unit  505 . In the lowered position (shown), the light shield  510  extends just to or past the threaded fastener head  525  when in a lowered position.  
         [0057]     Still referring to  FIG. 6 , the imaging device  520  images the back-lit threaded fastener head  525 . In some embodiments, the imaging device  520  comprises an imaging device lens  575 . The present invention is not limited to a particular type of imaging device  520  (e.g., digital camera, manual camera). In preferred embodiments, the imaging device  520  is a digital camera having a CCD chip to capture an image. In further preferred embodiments, the imaging device is a Legend 540 DVT Smart Image Sensor. In further preferred embodiments, the imaging device  520  comprises a processor. The imaging device  520  is not limited to a particular location within the threaded fastener head inspection system  500 . In preferred embodiments, the imaging device  520  is located above the light shield  510 . The imaging device  520  is not limited in its range of view. In preferred embodiments, the range of view of the imaging device  520  is at least the entire portion of the threaded fastener head  525 . In further preferred embodiments, the imaging device  520  height is adjustable to accommodate various threaded fastener head  525  dimensions.  
         [0058]     The threaded fastener head inspection system  500  of the present invention generates an image of a threaded fastener head. In preferred embodiments, the image is a digital image. In further preferred embodiments, the digital image comprises an array of pixels that can be used to represent distances (e.g., diameter, radius) across the threaded fastener head image.  
         [0059]      FIG. 7  is a representative depiction of an image  600  of a threaded fastener head obtained from the threaded fastener head inspection systems  500  of the present invention. As illustrated in  FIG. 7 , the center area is a silhouette image  605  of the threaded fastener head ( 525 , see  FIG. 6 ); the light reflected from the reflector ( 510 , see  FIG. 6 ) is represented as a reflector circle  610  directly around the silhouette image  605 ; and the outer circle  615  represents a shadow created by the light shield ( 520 , see  FIG. 6 ). The interface  620  between the silhouette image  605  and the reflector circle  610  represents the outer circumference of the threaded fastener head ( 525 , see  FIG. 6 ).  FIG. 7  also illustrates a threaded fastener with a blemish  620 .  FIG. 7  further illustrates various points on the image  600  of the threaded fastener head that are used for subsequent image analysis: the center point  625  and the radius  630 .  
         [0060]     In some embodiments, the image is analyzed using a processor programmed with instructions for identifying damaged threaded fastener heads. In some preferred embodiments, the processor is located in the imaging device itself, while in other embodiments, the imaging device interfaces with a remote processor in a desktop computer.  
         [0061]     The present invention is limited to a particular method of image analysis. In preferred embodiments, the analysis of threaded fastener head images comprises identifying the center point on the threaded fastener head, measuring a plurality of radius distances from the center point  625  to the interface  620 , and comparing the measurements to predetermined values or ranges. Of course, it will be recognized that the predetermined values or ranges can differ for various threaded fasteners.  
         [0062]     The present invention is not limited to a particular method of identifying a threaded fastener head center point in the image. In preferred embodiments, the processor is programmed with an algorithm for identifying the center point  625  of a threaded fastener head. In some embodiments, the center point  625  is identified by locating the interface  635  between the silhouette image  605  and the reflector circle  610 . The processor then analyzes the interface  620  in varying increments and calculates the center of the silhouette image  605 . In a preferred embodiment, the increments are 20.2 degree increments.  
         [0063]     In some embodiments, the calculated center point is then used as the basis for producing a plurality of threaded fastener head image radius measurements. The present invention is not limited to a particular method of obtaining a plurality of threaded fastener head image radius measurements. In preferred embodiments, the processor is programmed with an algorithm for obtaining threaded fastener head image radius measurements. In preferred embodiments, the processor is programmed to determine the distance (represented by pixels or fractions of pixels) from the threaded fastener center point  625  to the interface  635 . The present invention is not limited to a particular number of threaded fastener head image radius measurements. In preferred embodiments, the processor is programmed to determine the radius distance for each 0.5 degree incremental rotation along the interface  635 . Accordingly, in some embodiments  720  incremental radius measurements are calculated.  
         [0064]     In preferred embodiments, the processor is programmed to determine the difference between radius measurements at each 0.5 degree interval. These measurements are then compared to a predetermined value or range (e.g., the maximum allowable distance between two successive measurements). Threaded fastener heads that produce measurements not in accordance with the predetermined range or value (e.g., threaded fastener heads with blemishes) are designated with a fail condition.  
         [0065]     The present invention is not limited in the amount or type of radius distance comparisons. In some preferred embodiments, the processor is programmed to make a series of radius distance comparisons for a particular degree range (e.g., 0.0 degrees to 10.0 degrees, 5.0 degrees to 15.0 degrees, 350.0 degrees to 360.0 degrees, 355.0 degrees to 5.0 degrees, etc.) along the interface. Each degree range (e.g., 10 degrees) along the interface  635  comprises a number of radius measurements (e.g., for radius measurements of 0.5 degrees, a 10 degree range has 20 radius measurements) that are averaged for comparison purposes. By staggering the radius distance comparisons for a particular degree range (e.g., 0.0 degrees to 10.0 degrees, 5.0 degrees to 15.0 degrees, 350.0 degrees to 360.0 degrees, 355.0 degrees to 5.0 degrees, etc.), an overlap in the comparison process along the interface  635  is obtained. The processor is programmed to compare radius distance comparisons for a particular degree range obtained from the image  600  to a predetermined range for the radius distance comparison. Threaded fasteners not falling within the predetermined range are identified as damaged and are assigned a fail condition. In preferred embodiments, threaded fasteners assigned a failed condition are removed from the line by an index shift mechanism.  
         [0066]      FIG. 8  schematically illustrates a threaded fastener inspection system embodiment for inspecting a plurality of threaded fasteners. In particular, a threaded fastener head damage inspection system  800  interfaces with a first discard location  805  and/or a threaded fastener thread damage inspection system  810 . The threaded fastener thread damage inspection system  810  interfaces with either a second discard location  815  or an acceptance location  820 . The present invention is not limited to a particular threaded fastener inspection system configuration. Indeed, in some embodiments the present invention provides only a threaded fastener head damage inspection system  800  or only a threaded fastener thread damage inspection system  810 . In preferred embodiments, the present invention provides both a threaded fastener head damage inspection system  800  and a threaded fastener thread damage inspection system  810 .  
         [0067]     All publications and patents mentioned in the above specification are herein incorporated by reference. Variations and modifications of the foregoing are within the scope of the present invention. It is understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art.  
         [0068]     Various features of the invention are set forth in the following claims.