Abstract:
An inspection system is provided that includes at least one three-dimensional camera that is used to inspect an object to determine whether the object contains any defects. The defects that are capable of being detected by the inspection system include holes, tears, and improper thickness, and overlap. The inspection system is configured to alert a user in the event that the object contains a defect.

Description:
BACKGROUND 
       [0001]    The present embodiments relate generally to a system for inspecting an object using a three dimensional camera. 
         [0002]    Tire belt formation is a well-known practice that involves pulling multiple cords through an extrusion die. The extruder heats elastomeric material and coats the cords traveling through the die. Cooling drums adjacent to the extruder act both to pull the cords through the die and cool the fiber reinforced material before the cutting and splicing phase of production. After traveling through the cooling drums, the fiber reinforced material is allowed to hang with some slack in order to remove some residual forces. The fiber reinforced material is then drawn onto a cutting station. The cutting station includes a strip vacuum transfer, a cutter, and a belt conveyor. The strip vacuum transfer advances the fiber reinforced strip and positions it on the belt conveyor so that the cutter may cut the fiber reinforced material. The belt conveyor then indexes a predetermined distance. The strip vacuum transfer again advances the strip onto the conveyor so that the cutter again cuts it. This process results in a continuous belt of fiber reinforced material with the reinforcing cords lying at some angle typically not parallel to the central axis of the belt. 
         [0003]    Defects can occur during the tire belt formation process that could potentially render the product unusable. For example, the tire belt formation process may result in a tire belt that contains holes or tears or has an improper thickness, width, or splice. To minimize or prevent these and other common defects from occurring, inspection systems are used to inspect the product. Traditional systems rely on a two-dimensional camera to inspect the tire belt for defects. These traditional two-dimensional camera systems require a strong backlight or front light to enable the two-dimensional camera to detect certain defects, such as holes and tears. The light illuminates the inspection area and illuminates defects such as holes that pass entirely through the product. 
         [0004]    The two-dimensional camera, by its definition, is unable to detect defects that do not result in the complete penetration of the product because it is unable to detect differences in thickness. In other words, the two-dimensional camera system is limited in its ability to detect variances in height and depth that are not detectable on the X and Y-axes. It is for at least this reason that a better, improved inspection system is needed to identify defects that are not detectable using a traditional two-dimensional camera inspection system. 
       SUMMARY 
       [0005]    One embodiment of the present invention includes an inspection system having a roller assembly having a rolling surface, a first three-dimensional camera adjacent to the roller assembly and configured to measure an object on the rolling surface, a laser disposed adjacent to the first three-dimensional camera, the laser configured to project a laser beam on the rolling surface, and a monitoring system in communication with the first three-dimensional camera, where the monitoring system compares the measurement obtained from the first three-dimensional camera to a parameter. 
         [0006]    Other embodiments of the present invention further provide for a second three-dimensional camera that is disposed adjacent to the first three-dimensional camera, the first three-dimensional camera is disposed above the rolling surface, and where the laser forms part of the first three-dimensional camera, is separate from the first three-dimensional camera and is disposed between the first three-dimensional camera and the second three-dimensional camera; where the first three-dimensional camera and the second three-dimensional camera are configured to measure the width, offset, and thickness of an object and are configured to detect any holes, whether through holes or not, in an object; and where the monitoring system further comprises an alarm that notifies a user if the measurement from the first three-dimensional camera exceeds a certain parameter. 
         [0007]    Yet another embodiment of the present invention includes an inspection system having a roller assembly having a rolling surface, first and second three-dimensional cameras adjacent to the roller assembly and configured to measure an object on the rolling surface, a laser disposed between the first and second three-dimensional cameras, the laser configured to project a laser beam on the rolling surface, and a monitoring system in communication with the first three-dimensional camera, the monitoring system configured to compare a measurement from the first three-dimensional camera to a parameter. 
         [0008]    Other embodiments of the present invention include the first and second three-dimensional cameras being disposed above the rolling surface; the measurement of an object that can include the thickness, width, and offset of the object; where the laser is configured to illuminate a portion of the object that is being monitored by the first and second lasers; and where the laser is independent from the first and second three-dimensional cameras. 
         [0009]    One method of using one of the embodiments of the present invention for inspecting an object includes providing a roller assembly having a rolling surface, a first three-dimensional camera adjacent to the roller assembly, and a laser disposed adjacent to the first three-dimensional camera, placing the object on the rolling surface of the roller assembly, projecting a laser beam on a surface of the object, rotating the roller surface, measuring the object with the first three-dimensional camera, communicating the measurement to a monitoring system, and comparing the measurement to a parameter. 
         [0010]    The method may further include providing a second three-dimensional camera with the first three-dimensional camera, measuring the object that includes inspecting the object for any holes where measuring the object includes measuring the width, offset, and thickness of the object, notifying a user if a measurement of the object is outside of a parameter, and inputting a parameter into an inspection system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views. 
           [0012]      FIG. 1  is a perspective view of an inspection system of one embodiment of the present invention. 
           [0013]      FIG. 2  is a front view of the inspection system shown in  FIG. 1 . 
           [0014]      FIG. 3  is a perspective view of the laser used to inspect an object using the inspection system of  FIG. 1 . 
           [0015]      FIG. 4  is a partial schematic of an inspection software, encoder, and cameras used for the inspection system shown in  FIG. 1 . 
           [0016]      FIG. 5  is a perspective view of a tire belt making system that may employ the inspection system shown in  FIG. 1 . 
           [0017]      FIG. 6  is an operational flow chart depicting an exemplary inspection procedure. 
           [0018]      FIG. 7  is a partial front view of the inspection system shown in  FIG. 1  and a calibration system. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0019]    Referring to  FIGS. 1-7 , an inspection system is generally indicated by numeral  10 . The inspection system  10  may be used in any tire belt making system or any other system where defects can exist. One example of such a tire belt making system can be found in U.S. Pat. No. 7,497,241, the disclosure of which is incorporated herein by reference in its entirety. In the tire belt making system disclosed by the &#39;241 patent, the inspection system  10  is located after the bias cutter. However, this is only exemplarily in nature, and it can be appreciated that the system  10  can be configured to be placed in any desirable location and can be used to inspect any other object that may have surface defects, such as sheets made out of polymers, metals, other composite materials, and the like. 
         [0020]    As shown in  FIGS. 1 and 2 , the inspection system  10  includes a frame  12  having a bottom frame portion  14  connected to a top frame portion  16 . The top frame portion  16  includes a top cross-member  18 . Disposed within the frame is a drum  20 . The drum  20  includes a rolling surface  22  and has a first end  24  and a second end  26  that are rotatably connected to the frame  12 . This allows the drum  20  to rotate within the frame  12  during the inspection process. 
         [0021]    A motor  28  is configured to impart a rotational force on the drum  20  to allow the drum  20  to rotate within the frame  12 . The rotation of the drum  20  translates an object that is placed along the rolling surface  22  from one side of the frame  12  to the other and along to another device. It can be appreciated that the drum  20  may also consist of one or more miniature rollers to accomplish the same task of moving the object relative to the frame  12 . The speed of the drum  20  can be controlled by the PLC and loop photo-eyes. 
         [0022]    A feeding track  30 , as shown in  FIG. 1 , may also be used to orientate the object, which in this embodiment is a tire belt, prior to coming in contact with the drum  20 . The feeding track  30  can consist of a series of rollers  32  and two alignment arms  34  to align the tire belt to ensure that it is properly orientated on the rolling surface  22  for the inspection process. 
         [0023]    As shown in  FIG. 2 , coupled to the cross member  18  are two three-dimensional cameras  36 . The three-dimensional cameras  36  are positioned over the drum  20 , and specifically the rolling surface  22 , so as to inspect the object as it is being passed over the rolling surface  22  beneath the cameras  36 . The drum  20  may be calibrated so that it is completely level and perpendicular to the inspection field of the three-dimensional cameras  36 . The three-dimensional cameras  36  can measure various parameters of the object, such as its height, thickness (i.e. elevation), and depth in order to detect deformities within the object that is being manufactured or inspected. For example, the three-dimensional cameras  36  can measure parameters such as belt width, belt thickness, offset splice (i.e. dog ears), open splices, splice overlap, and splice thickness of a tire belt during the various stages of the manufacturing process. It also can detect holes and foreign objects that may be embedded within or disposed on the tire belt. One type of three-dimensional camera  36  that can be used with this system is the Sick ICD-3D 100 camera, manufactured by SICK Inc. of Minneapolis, Minn. It can be appreciated that other three-dimensional cameras with similar functionality may be used with the present invention. 
         [0024]    Furthermore, it can be appreciated that the location and the number of three-dimensional cameras  36  are application dependent and may vary from application to application. For example, and without limitation, there may only be one three-dimensional camera  36  or more than two, depending on the size of the object to be inspected. For example, in one embodiment used for the tire belt, if the tire belt width is less than 230 mm, only one camera may be required. Two cameras may be used for widths up to 471 mm. Of course, these width dimensions are for one particular application that is using one particular 3-D camera, and the inspection field width of the three-dimensional camera used in the system  10  may vary depending on the type of camera used. 
         [0025]    In addition, the location of the three-dimensional cameras  36  may change depending on the orientation of the surface to be inspected. If the side or bottom surface of the object is to be inspected, then the three-dimensional cameras  36  may be disposed to the side or underneath the object, respectively. 
         [0026]    The functionality of the three-dimensional camera  36  enables inspection of an object in a manner that is not possible by a traditional two-dimensional camera. In addition to the parameters discussed above, the three-dimensional camera  36  may also be used to detect holes, open splices, or tears within the surface of the object that do not penetrate all the way through the object. Such deformities would not be detectable by a two-dimensional camera because they are only detectable by measuring the thickness of the material about an axis that is perpendicular to the surface of the object. 
         [0027]    A laser  38  is disposed between the two three-dimensional cameras  36  as shown in  FIG. 2  and mounted on the cross member  18 . The laser  38  is used to illuminate the region of the object that is being scanned or monitored by the three-dimensional cameras  36 . In this embodiment, the laser  38  is aligned with the two cameras  36 . However, it can be appreciated that the laser  38  may also be positioned at a different location, such as to one side of the three-dimensional cameras  36 . The width of the laser projection on the object may be at least as wide as the width of the inspection field generated by the three-dimensional cameras  36 . The laser  38  in this embodiment is separate and apart from the two three-dimensional cameras  36 . This is because the lasers disposed within the three-dimensional cameras  36  project beams that partially overlap with one another, which results in measurement errors by the three-dimensional cameras  36 . Unless the mechanical alignment of the two lasers is precise, the adjacent three-dimensional camera  36  may show a discontinuity in the overlap region. 
         [0028]    By using a third independent laser  38 , neither three-dimensional camera  36  sees an overlapped laser line. The data captured by the two three-dimensional cameras  36  from the overlap region captured by the three-dimensional cameras  36  may be manipulated such that the discontinuity is removed. Moreover, by using an independent laser  38 , a “Class 2” laser may be used to accomplish the measurement of wider belts at an acceptable resolution and speed. This may not be the case with the laser within the three-dimensional camera  36  because the three-dimensional camera  36  must be farther away to “see” the entire belt width and a stronger (brighter) laser may be needed, which may require eye protection. 
         [0029]    As shown in  FIG. 3 , the laser  38  has a laser beam angle a that is projected onto the object. As mentioned above, the angle a must be wide enough to cover the portion of the object that is being measured or inspected by the three-dimensional cameras  36 . It can also be appreciated that more than one laser  38  may be used if there are discrete sections of the object that need to be inspected or measured such that the two laser beams do not overlap with one another. 
         [0030]    An encoder  40 , as shown in  FIG. 2 , may be in communication with the three-dimensional cameras  36  so as to retrieve and process the data collected from the three-dimensional cameras  36  for processing by an inspection software  42 . The encoder  40  is used to clock image profiles to the camera system  36  in order to build a three-dimensional image of the belt material. This information and other related data can be recorded to log files or by a data acquisition computer. 
         [0031]    The inspection software  42 , as shown in  FIG. 4 , is in communication with the encoder  40 , which in turn is in communication with the cameras  36 . It can be appreciated that the software  42 , encoder  40 , and cameras  36  may be entirely or partially in wireless communication with one another. It is also contemplated that the three-dimensional cameras  36  may be in direct communication with the inspection software  42 . 
         [0032]    One type of inspection software  42  that can be used with the system  10  is IVC Studio 3.2, manufactured by SICK Inc. of Minneapolis, Minn. It can be appreciated that other types of software may also be used with the inspection system  10 . The inspection software  42  is designed to configure and calibrate the camera(s) to inspect or monitor the object/product and compare the characteristics of the object/product to parameters that are inputted by a user. 
         [0033]    The three-dimensional cameras  36  rely on precise calibration and alignment in order to function and operate in the intended manner. The software system  42  also includes a calibration feature that enables the three-dimensional cameras  36  to be calibrated prior to use. As shown in  FIG. 7 , the inspection system  10  may include a calibration fixture  48  to aid in the calibration process. The calibration fixture  48  allows the inspection software  42  to calibrate the three-dimensional cameras  36  by leveling the cameras  36  using the laser beams of the three-dimensional cameras  36  with respect to the calibration fixture  48  and thus the drum  20  and rolling surface  22 . Once the three-dimensional cameras  36  are leveled, the calibration fixture  48  can be flipped over such that a thin groove is showing. The inspection software  42  can then be used to align the laser beams of the cameras  36  such that they are centered inside the small groove of the calibration fixture  48 . The three-dimensional cameras  36  can be adjusted using set screws  50  within the camera brackets  52  that are attached to the cross member  18 . Alternatively, the cross member  18  includes slotted holes  54  that enable the entire cross member  18  to be adjusted to calibrate the three-dimensional cameras  36 . The three-dimensional cameras  36  can also be calibrated to measure the overall belt width by using a calibration bar. The fixture surface is calibrated by initializing the software  42  to capture the image of the surface. 
         [0034]    Another aspect of calibrating the three-dimensional cameras  36  includes using the lasers built into the three-dimensional cameras  36  to align them to the drum  20 . To do so, the laser beams of the three-dimensional cameras  36  are aligned with the laser beam that is generated by the laser  38  in a manner such that the leaser beams of the three-dimensional cameras  36  do not overlap but are collinear with one another. Once all the beams are aligned, the laser beams of the cameras  36  are turned off while the laser  38  remains on and is used during the inspection process. In addition, and to the extent necessary, the drum  20  may also be leveled using jack screws  56 . Preferably, the drum  20  is level to the cameras  36  as well such that a portion of the rotating surface  22  is perpendicular to the inspection field generated by the three-dimensional cameras  36 . 
         [0035]    Typically, as mentioned above, the inspection system  10  can be used with a tire belt making system. A discussion of one process of cutting and splicing the tire strips to manufacture a tire belt can be found in above-referenced U.S. Pat. No. 7,497,241. For example, the system  10  may be placed after the bias cutter of a tire manufacturing system. The inspection system  10  will be positioned at a location to allow it to inspect the tire strips once they have been cut and spliced together. 
         [0036]    A discussion of the operation of the inspection system  10  in the context of inspecting a tire belt follows. However, it can be appreciated that the inspection system  10  can be used for other types of materials and the discussion below is not intended to limit the scope of the present invention. 
         [0037]    As shown in  FIG. 5 , the inspection system  10  is disposed after the cutter  44  in this configuration. The tire belt  46  is positioned onto the feeding track  30  and on top of the rolling surface  22  of the drum  20 . The laser  38  projects a laser beam across the width of the tire belt  46  and the two three-dimensional cameras  36  inspect the illuminated portion of the tire belt  46  for any defects. Specifically, the two three-dimensional cameras  36  gather the thickness data of the tire belt  46  and combine it with the encoder feedback  40  to generate a three-dimensional image of the tire belt  46 . Once the three dimensional image is generated, dimensional data of the image are compared to the user inputted parameters by the inspection software  42 . As discussed above, these parameters include, but are not limited to, the belt width, splice dog-ear (i.e. offset splice), open splices, and splice thickness. In addition, the parameters may also include belt thickness to determine if there are any tears or holes in the tire belt. 
         [0038]    Referring now to  FIG. 6 , a flow chart, designated generally by the numeral  100 , is representative of one embodiment of computer readable media tangibly embodying a program of instructions that could be contained in the inspection software  42  or central control unit for inspecting the tire belt  46 . The method steps of the software may be programmed to any computer or machine-readable media, and performed by a suitable computer such as a control unit. The process begins when the inspection system  10  is initialized  102 . The central control unit may inquire if the inspection software  42  is enabled  104 . If not, the central control unit will take no further action. If the software  42  is initialized  102 , it will inspect the object, which in this embodiment is the tire belt, to determine whether the inspected section falls within the user specified parameters  106 . If the tire belt section  46  falls within the user specified parameters, no action is taken. If the tire belt section  46  falls outside of the specified parameter, the software  42  sends a notification to a user and a command to stop the manufacturing line  108 . It can be appreciated that the parameter contemplated may be a single parameter or a host of parameters and that the command to stop the manufacturing line may occur if any one of parameters are violated or if only certain parameters are violated. 
         [0039]    While various embodiments of the invention have been described, the invention is not to be restricted except in light of the attached claims and their equivalents. Moreover, the advantages described herein are not necessarily the only advantages of the invention and it is not necessarily expected that every embodiment of the invention will achieve all of the advantages described.