Fixing device and method for optical alignment in special-shaped glass sheet surface measuring system

Abstract

An optical inspection system is provided with a fixture for supporting a glass sheet, the fixture having an optical reference. The ultraviolet laser and associated optics form a planar, sheet-shaped laser beam that intersects the surface of the glass sheet, thereby causing the surface to fluoresce and form visible wavelength lines on the surface. The camera has an image sensor for detecting an optical reference and a visible wavelength line across at least a portion of the width of the sheet. The control system is configured to (i) image the optical reference on the stationary device, (ii) define an optical reference coordinate system from the imaged optical reference, (ii) receive a mathematical model of the glass sheet in a model coordinate system, and (iii) associate the optical reference coordinate system with the model coordinate system via at least one transformation. A method of using the non-contact optical inspection system is also provided.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application serial number 17 / 884,116 filed on August 9, 2022, the disclosure of which is hereby incorporated by reference in its entirety. Technical Field

[0003] Various embodiments are directed to fixtures and methods of using the fixtures with systems for optically measuring a surface of a shaped glass piece. Background Art

[0004] Manufacturers of glass sheets, particularly glass sheets formed into various curved shapes for use as automotive windshields, rear windows, and side windows, are interested in measuring and evaluating the surface of the glass sheets. The manufacturer may wish to determine whether the glass sheet is within predetermined metrological specifications. The manufacturer may also wish to measure and evaluate the amount of reflected optical distortion in the formed sheet, which may be perceived by a human observer, such as an external observer or an operator or passenger of a vehicle in which the glass may be installed as a windshield, rear window, side window, etc. For example, with the increased use of technology such as heads-up displays in vehicle applications, metrological metrics and reflective distortion thresholds are becoming increasingly stringent.

[0005] As part of measuring or metrology of a glass sheet, it may be necessary to determine the position of the glass sheet within a scanning system. Using conventional glass sheet support fixtures may not work with optical inspection systems that employ non-contact measurement or metrology, and the optical inspection system may not be able to precisely and / or accurately position the glass sheet without the use of a calibrated fixture. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 A schematic diagram showing one embodiment of a glass sheet inspection system according to one embodiment is shown;

[0007] Figure 1A Shown with Figure 1 A schematic diagram of an optical inspection subsystem for use with a glass sheet inspection system;

[0008] Figure 2 Shows the use of Figure 1 A flowchart of a method for optically aligning a fixture to measure a glass sheet using an optical inspection system;

[0009] Figure 3 According to one embodiment, Figure 1 A perspective view of a fixture for use with an inspection system and without a glass sheet;

[0010] Figure 4Shown is a glass sheet Figure 3 A three-dimensional diagram of the fixing device;

[0011] Figure 5A , Figure 5B and Figure 5C shows the calibration Figure 1 The optical coordinates of the various configurations of the system Figure 1 A schematic diagram of a fixture in the system; and

[0012] Fig. 6A , Figure 6B , Figure 6C and Fig.6D shows the calibration used with Figure 1 systems and Figure 2 One or more methods of using an optical coordinate system, a CMM coordinate system and a CAD coordinate system together with the method;

[0013] Figure 7 According to another embodiment, Figure 1 Inspection system and Figure 2 A perspective view of a fixture for use with the method and without a glass sheet;

[0014] Figure 8 Shown is a glass sheet Figure 7 a schematic cross-sectional view of a fixing device; and

[0015] Fig. 9 According to yet another embodiment, Figure 1 Inspection system and Figure 2 A perspective view of a fixing device used in conjunction with the method. DETAILED DESCRIPTION

[0016] As required, detailed embodiments of the present disclosure are provided herein; however, it should be understood that the disclosed embodiments are merely examples and may be embodied in various alternative forms. The drawings are not necessarily drawn to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, the specific structural and functional details disclosed herein should not be interpreted as limiting, but should only be interpreted as a representative basis for teaching those skilled in the art to adopt the present disclosure in various ways.

[0017] It should be recognized that any circuit or other electrical device disclosed herein may include any number of microprocessors, integrated circuits, memory devices (e.g., FLASH, random access memory (RAM), read-only memory (ROM), electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM) or other suitable variants thereof) and software that cooperate with each other to perform (one or more) operations disclosed herein. In addition, any one or more electrical devices disclosed herein may be configured to execute a computer program embodied in a non-transitory computer-readable medium programmed to perform any number of functions disclosed herein.

[0018] Figure 1 An inline glass sheet optical inspection system 10 is shown. Examples of subsystems used with the system 10 and fixture 14 of the present disclosure are described in PCT patent application serial number PCT / US19 / 43180, entitled “System And Method For Measuring A Surface In Contoured Glass Sheets,” filed on July 24, 2019, the disclosure of which is incorporated herein by reference in its entirety. In other examples, other non-contact optical inspection systems can be used with the present disclosure.

[0019] The inspection system 10 includes a conveyor 12 that conveys a glass sheet G (also referred to as a glass panel G) in a first direction that is generally parallel to a first dimension of the glass sheet. In the example shown, the shaped glass sheet G is a vehicle windshield or backlight that is generally trapezoidal, having a first dimension that is a relatively small dimension (and may alternatively be referred to as a height) and a relatively large second dimension (and may alternatively be referred to as a width). The glass sheet G has a third dimension of thickness that is less than the width and the height. The glass sheet G is curved about one or more axes of curvature that are generally parallel to the first direction. In other examples, the glass sheet G may have other axes of curvature, may be provided as a flat or substantially flat sheet, or may be otherwise shaped.

[0020] The conveyor 12 can be a single conveyor dedicated to transporting the glass sheet G through the inspection system 10, which can be configured and / or operated as an independent optical inspection system. In other examples, the conveyor 12 can be one of a series of conveyors that convey the glass sheet through various processing stations, such as heating stations, forming stations, and annealing or tempering stations found in typical automotive, architectural and / or solar glass sheet manufacturing systems. The conveyor of the glass sheet G can be provided by various technologies (e.g., by rollers, air flotation or belt conveyors, positioners, and robotic arms) to process the glass in the manner described. It should also be understood that each of the multiple conveyors can be independently controlled to move the glass sheet through different processing stations at a speed that effectively manages the flow and processing of the glass sheet in the entire system 10. Alternatively, the inspection system 10 can be set as a separate independent system or device without a conveyor.

[0021] The inspection system 10 may also be provided with a fixture 14 for the glass sheet G. The fixture 14 supports and positions the glass sheet G thereon. The fixture 14 may provide precise and accurate positioning of the glass sheet G. Figure 3 and Figure 4 as well as Figures 7 to 9 Describe in more detail Figure 1 A fixing device for use with a system.

[0022] Inspection subsystem 16 can be configured to translate relative to sheet G and fixture 14, for example, inspection subsystem 16 is mounted on the conveyor system and / or fixture 14 is mounted on conveyor system 12. Inspection subsystem 16 has optical elements configured to scan the surface of glass sheet G based on the movement of inspection subsystem 16 relative to fixture 14.

[0023] Inspection subsystem 16 may be used to measure the surface of a glass sheet and may also be used to metrology the sheet, measure small surface curvature defects in the sheet, and / or measure reflected optical distortion. Figure 1A Describes an example of Figure 1 The system 10 is used with the fixture 14 and an inspection subsystem 16 .

[0024] According to one example, the inspection subsystem 16 is a non-contact optical system having one or more cameras or other detectors to image or otherwise detect light used to measure and / or meter the glass sheet G. In the example shown, the inspection system 16 can detect light at visible wavelengths or non-visible wavelengths (e.g., in the ultraviolet or infrared wavelength ranges).

[0025] refer to Figure 1 and Figure 1A, and according to another non-limiting example, the subsystem 16 includes a detector 30 such as a camera and a light source 40 such as a laser. The detector 30 may be provided by a single camera or multiple cameras that image different areas of the glass sheet G. In a multi-camera system, the areas imaged by the cameras may overlap or not overlap. According to one example, the subsystem 16 has a laser 40 or other light source whose wavelength is selected at least in part based on the optical properties of the glass sheet G. The light source may output light of a visible or invisible wavelength (e.g., in the ultraviolet or infrared wavelength range). Light from the light source 40 is directed to the glass sheet G by the subsystem 16. In one example, the light source is selected to have a wavelength λ1 in a tuned narrow band to which the glass sheet G is opaque or substantially non-transmissive. The light source 40 is also selected so that the wavelength λ1 of the light source causes or causes the surface of the glass sheet G to emit light at a wavelength λ2 different from the wavelength λ2 of the light source. For example, the light source 40 is selected so that the wavelength λ1 of the light source causes or causes the surface of the glass sheet G to fluoresce or luminesce at a wavelength λ2 that is longer than the wavelength λ1 of the light source. In another example, the laser 40 is a pulsed diode laser tuned to provide ultraviolet light of a specific wavelength to which the glass sheet G is opaque or non-transmissive, or to which the glass sheet G is substantially non-transmissive, e.g., less than 5% or 2% transmittance for the laser output, while the glass sheet fluoresces in the visible spectrum.

[0026] The subsystem 16 may also include various optical elements 42 for controlling and directing light from the light source to the glass sheet G and from the glass sheet G to the detector. The optical elements 42 may be configured to provide a planar sheet-shaped laser beam to one of the two surfaces 44, 46 of the glass sheet G. The planar sheet-shaped laser beam may extend, for example, laterally across the conveyor in the x-direction. The first surface 44 and the second surface 46 are spaced apart from each other by the thickness of the glass sheet G. Since the glass sheet G is opaque or substantially non-transmissive to the wavelength λ1 of the sheet-shaped laser beam, the sheet-shaped laser beam interacts with the first surface 44 without passing through the sheet G or reaching the second surface 46, and thus excites the glass sheet G only at the first surface 44, so that visible light of wavelength λ2 appears on the surface 44. The emitted light is detected by the camera(s) 30 of the system 10.

[0027] The camera 30 may be provided with a charge coupled device (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor. In the present example, the detector 30 is provided with a CMOS sensor and is positioned so that the entire width of the glass sheet G or the entire width of the glass sheet in the x direction is captured in the image. In the example shown, the camera is provided by a 5496×3672 pixel CMOS sensor camera, which is set to a region of interest of 5496×1836 or 5496×1000 pixels in one example, or a 5120×5120 pixel CMOS sensor in another example. Various camera settings may be controlled based on laser parameters, conveyor speed, and other system factors, including lens focal length, aperture, gain, and exposure time. In one example, the camera uses a fixed lens, such as a 16 mm or 25 mm lens, and is set to an aperture of f2.4 or higher to increase depth of field, and uses an exposure time of 15-20 milliseconds and a gain of 2-15 decibels. In another example, the camera setting may use another exposure time, for example in the range of 10 milliseconds to more than 300 milliseconds, and the gain may also be set to another value in the range of 2 to 30 decibels. In other examples, the camera 30 may be positioned to image only selected areas of the sheet G. In other examples, the detector may be set as another photodetector or photosensitive element. In other examples, additional optical elements such as filters may be provided between the glass sheet G and the detector 30 to further improve the signal-to-noise ratio.

[0028] Subsystem 16 has at least one computer and / or control unit 18 including at least one processor program to execute logic for controlling an optical system including detector(s) and any light source(s), acquiring data for each glass sheet from the detector(s), analyzing the data for the glass sheet, and providing information related to the surface shape, reflected optical distortion, or other surface information or defects of the glass sheet. As shown, the computer may be integrated with a control system 20 of inspection system 10, or may be provided as a separate device in communication with control system 20. Control system 20 may include a programmable control unit or computer for detecting glass sheets as they advance on the conveyor and controlling the movement and speed of conveyor 12.

[0029] Thus, optical subsystem 16 provides a non-contact inspection system for rapidly acquiring detailed data corresponding to the surface of glass sheet G and analyzing the acquired surface data to evaluate and report the surface shape of glass sheet G and properties related to the optical properties of glass sheet G, for example, while glass sheet G is transported on conveyor 12 between or after bending, cooling, or other processing operations for a time sufficient to scan and analyze glass sheet G or provide measurements or metrology of glass sheet G or its surface.

[0030] The conveyor 12 moves the fixture 14 with or without the glass sheet G along a path or direction (shown here as the y-direction) past the optical system 16. The conveyor 12 is moved using one or more motors and support rollers or other devices.

[0031] The inspection system 10 has one or more position sensors 22 for determining the position and timing of the conveyor 12 for analyzing the glass sheet G using the subsystem 16, and for calibrating the subsystem 16 using the fixture 14. The position sensor(s) 22 may be provided by a digital encoder, an optical encoder, etc. The position sensor 22 may be used as an input to the optical system 16 to determine the timing of data acquisition, such as as a trigger for a camera.

[0032] The inspection system 10 may be provided with additional sensors, such as photoelectric sensors, etc., in communication with the control systems 18, 20 for determining that the fixture 14 or the glass sheet G is in the proper position on the conveyor 12, or has advanced to the subsystem 16. The computers 18, 20 then communicate with the subsystem 16 to activate the system 10 and begin measuring the surface of the sheet G. In other examples, the optical system 16 may operate continuously and may begin acquiring and processing data related to the glass sheet G in response to the system 10 detector registering an appropriate signal indicating that the light source has begun to interact with the glass sheet G.

[0033] In use, the system 10 can measure or meter the glass sheet G by using the light source 40 and the camera 30. The system 10 can scan and image the glass sheet G and create a three-dimensional map or point cloud of the surface of the glass sheet G.

[0034] To measure or meter the glass sheet G, the computer 18 receives image data from the camera 30 as a series of data indicating a series of visible wavelength lines measured or detected using one or more cameras, wherein each camera images a region of interest of the glass sheet G. Each visible wavelength line is processed and analyzed to determine a first coordinate and a second coordinate in a series of coordinates associated with each line, such as (x, y) coordinates of the surface of the glass sheet, and store these coordinates in a matrix or point cloud associated with the camera. The computer 18 calculates a third coordinate, such as a (z) coordinate, from the position of the laser, the position of the camera, and the first and second coordinates using triangulation, and stores the (z) coordinate in the matrix or point cloud.

[0035] Computer 18 uses the data from the image to form a matrix or point cloud, such as a cell in the matrix associated with a location on the surface 44 of the glass sheet, or as an array of points in the point cloud associated with a location on the surface 44 of the glass sheet. A three-dimensional map of the surface of the glass sheet can then be created from the matrix or point cloud based on a series of coordinates for each of a series of visible wavelength lines of the glass sheet G of the camera. Since the laser does not pass through the glass sheet G, only the surface 44 facing the inspection system is luminescent. Therefore, the point cloud with a series of coordinates provides a three-dimensional, high-resolution mathematical model of the surface 44 of the glass sheet G through a series of (x, y, z) coordinates.

[0036] Prior to measuring or metrologically measuring glass sheet G to create a point cloud or map of surface 44, it may be necessary to calibrate system 10 in order to link the point cloud to a known coordinate system. The present disclosure relates to fixtures and methods for providing such calibration for system 10.

[0037] Figure 2 A flow chart of a method 100 for calibrating an optical inspection system according to one embodiment is shown. With respect to the method 100, steps may be rearranged or omitted, or additional steps may be added according to various embodiments.

[0038] At step 102, the subsystems 16 may be internally calibrated, for example, the camera, light source, and conveyor 12 may be individually calibrated.

[0039] System 10 is externally calibrated via one or more steps associated with 104 .

[0040] At step 106, a fixture is provided for use with the system 10. Figure 3 An example of a fixing device 200 without a glass sheet G is shown in FIG. Figure 4 An example of a fixing device 200 having a glass sheet G is shown in FIG. Figure 7 Another example of a fixing device 300 without a glass sheet G is shown in FIG. Figure 8An example of a fixing device 300 having a glass sheet G is shown in FIG. Fig. 9 The fixing device 400 is shown in FIG. The fixing device 200, 300 or 400 may be configured as Figure 1 The fixing device 14 in the embodiment of the present invention. Each fixing device is described in more detail below.

[0041] refer to Figure 3 and Figure 4 , the fixture 200 has an underlying frame 202. The frame can be supported on a conveyor of the system and can be used to lift or otherwise move the fixture. The frame 202 is provided with a fixture frame 204. In the example shown, the fixture frame has a side wall 206 extending upward from the frame to an upper surface 208. The shape of the side wall can be substantially similar to the outer perimeter of the glass sheet G intended for use with the fixture. The upper surface 208 of the side wall can be molded or otherwise formed to follow the surface of the glass sheet G, such as the lower surface 46. The side wall can extend continuously around the open central area 210.

[0042] A series of standoff pins 220 are provided extending upwardly from the upper surface 208. The series of standoff pins are spaced apart from one another around the upper surface of the side wall. The standoff pins are arranged to contact and support the glass sheet on the fixture. The series of standoff pins may define an A-base line for the fixture. When the sheet G is supported on the fixture, the lower surface 46 of the sheet is spaced apart from the upper surface 208 of the side wall so that the lower surface of the sheet does not contact the upper surface of the fixture and is supported only by the standoff pins.

[0043] The exact shape, size, and surface shape and contour of the actual glass sheet G may be different from the sheet defined in the CAD or other mathematical model of the glass sheet. Thus, based on the variability of the glass sheet G, the actual glass sheet G may not be in contact with each support pin 220. For fixtures with more than three support pins, and possible deviations of the actual sheet G from the mathematically or CAD modeled sheet, the system and fixture may be over-constrained. As shown, more than three support pins may be required to fully support the glass sheet on the fixture. In the example shown, there are twelve support pins, but a greater or lesser number of support pins may also be envisioned. In this case, any measurement data acquired by the subsystem 16 of the glass sheet G cannot be used to directly align the subsystem 16 point cloud of the surface of the glass sheet G with the CAD data, because the required assumption that all support pins 220 are in contact with the glass sheet G may introduce errors into positioning the glass sheet.

[0044] The fixture 200 may also be provided with an additional baseline for positioning the edge of the sheet G relative to the fixture. In the example shown, the fixture has a pair of B-baseline posts 230 and an associated B-baseline mechanism 232 for drawing the edge of the glass sheet G into contact with the B-baseline posts. The B-baseline posts may position the edge of the sheet G relative to the x-axis of the fixture. The B-baseline mechanism may be provided with a pneumatic or other operated cylinder 234 and an arm 236. The arm 236 contacts the edge of the sheet opposite the B-baseline posts and translates the sheet G along the x-axis until the sheet contacts the B-baseline posts. In other examples, there may be one B-baseline post.

[0045] In the example shown, the fixture also has a C-baseline post 240 and an associated C-baseline mechanism 242 for drawing the edge of the glass sheet G into contact with the C-baseline post. The C-baseline post can position the edge of the sheet G relative to the y-axis of the fixture. The C-baseline mechanism can be provided with a pneumatic or other operated cylinder 244 and an arm 246. The arm 246 contacts the edge of the sheet opposite the C-baseline post and translates the sheet G along the y-axis until the sheet contacts the C-baseline post. In other examples, there can be two C-baseline posts.

[0046] Although support 220 and B baseline posts 230 and C baseline posts 240 allow glass sheet G to be accurately positioned relative to fixture 200, subsystem 16 may not be able to accurately define or find the edge or boundary of the glass sheet with high accuracy and precision when imaging glass sheet G in system 10. For example, errors may be introduced in the measurement of the edge or the exact location of the edge in the point cloud of glass sheet G based on errors and artifact points generated by the interaction of light source 40 with surface 44 and edge of glass sheet G. An example of an edge effect or deviation in its measured location is caused by laser beam steering effects and / or deviations from the calculated line center of the fluorescent line on the surface of sheet G from the sheet-shaped laser beam. These effects or deviations may produce artifact points in the three-dimensional point cloud and introduce errors when locating the edge of the sheet using system 10. Since this is a non-contact inspection system 10, and it may be impossible or difficult to accurately and precisely define the definite edge of sheet G using three-dimensional point cloud data, it is still important to calibrate and align the fixture to provide a relevant coordinate system for system 10. Thus, the system 10 is used to otherwise align and calibrate the fixture 200 so that the system piece G surface data of the three-dimensional point cloud can be compared to the mathematical or CAD model to measure or measure the piece, or the alignment data of the fixture 200 can be compared to the CMM coordinate system and CAD model to verify the fixture alignment and coordinates and / or measure or measure the piece.

[0047] Therefore, the fixture 200 is provided with an optical reference 250, such as a checkerboard or other known planar calibration surface 250. In the example shown, the optical reference 250 is provided as a calibration surface within the open area 210 surrounded by the side walls of the fixture. The calibration surface can be positioned below the upper surface of the side wall so that the calibration surface remains on the fixture regardless of whether the glass sheet G is present. The calibration surface can be positioned close to the height of the adjacent glass sheet G. The optical reference 250 is positioned relative to the upper surface of the side wall so that the side wall does not obstruct a portion of the optical reference from the field of view of the associated camera. In another example, the optical reference can be removed from the fixture and positioned on the fixture only for alignment and calibration purposes and not positioned on the fixture when the system 10 is imaging the glass sheet G. In another example, the optical reference can be covered to protect it when the system 10 is measuring the glass sheet G.

[0048] In one example, an optical reference or calibration surface 250 is provided with a known number and size of chessboard squares. The calibration surface can be attached to a fixture at a known position and at a known angle, or can generally be positioned within the fixture and the relationship between the chessboard and fixture coordinates determined later. In the example shown, the calibration surface 250 is located at the center of the fixture and is formed as a plane or flat surface. When the calibration surface 250 is flat, the calibration surface can be tilted or angled relative to the fixture and / or relative to the camera viewing angle.

[0049] The optical fiducial 250 may be provided with a visual marker 252 or indicator to allow the system 10 to identify the fixture. For example, the visual indicator may be a barcode, such as a two-dimensional or three-dimensional barcode, or other visual indicator or label.

[0050] Optical fiducial 250 may also have three or more physical fiducials 270 , such as fiducial marks, for relating the position and alignment of optical fiducial 250 to physical fiducials 260 of fixture 200 .

[0051] In one example, for a system with one or more cameras, the entire optical fiducial 250 (e.g., checkerboard) is positioned to be visible to all cameras 30 or detectors of the system. In another example, for a system 10 with multiple cameras and multiple optical fiducials 250, each optical fiducial can be positioned so that it is within the entire field of view of the associated camera, with the system applying additional transformations to stitch or otherwise cross-reference multiple camera data together when creating calibrations and fixture alignments.

[0052] The fixture 200 may be provided with a physical fiducial 260, such as a tooling sphere 260 or other CMM surface, such as an edge or hole. The physical fiducial 260 may be used to correlate CMM coordinates and data with system calibration and alignment data from the optical fiducial 250 and from the fixture 200. In the example shown, the fixture 200 has three or more physical fiducials 260. The fixture may also have a physical fiducial 270 (e.g., a physical fiducial mark) on the calibration table to correlate the position and alignment of the optical fiducial 250 with the rest of the fixture in the CMM coordinate system determined from the physical fiducial 260. The use of a physical fiducial 260, such as a tooling sphere and / or CMM surface, and the CMM cannot be used alone to determine the position of the fixture in the system 10 because the system 16 uses non-contact optical inspection techniques and does not contact or otherwise physically engage the fixture.

[0053] The physical reference 260 or other fixture CMM surfaces are spaced apart from each other on the fixture. The fixture position and fixture coordinate system can be transformed into a computer-aided design (CAD) or other model coordinate system by using a coordinate measuring machine (CMM). In various examples, the CAD coordinate system can correspond to or be related to another coordinate system (such as a vehicle coordinate system or other final assembly coordinate system) used with the glass sheet G. The CMM device moves and physically contacts the tool ball or other alignment surfaces of the fixture to measure or calibrate the fixture. The CMM device determines the position of the tool ball on the fixture to provide three known coordinates of the fixture in the CMM coordinate system, for example as three known points in a Cartesian or other CMM coordinate system. For conventional systems and metrology, the surface of the glass sheet G will be contacted by tens or hundreds of probes in order to determine the points associated with the sheet and measure or measure the sheet surface.

[0054] refer to Figure 7 and Figure 8 According to another embodiment, another fixing device 300 is shown, which can be used as Figure 1 systems and / or Figure 2 For simplicity, components of the fixture 300 that are the same or similar to those shown and described above with reference to the fixture 200 are given the same reference numerals.

[0055] The fixture 300 has an underlying frame 202 that can be supported on a conveyor of the system and can be used to lift or otherwise move the fixture on a fixture frame 204. In the example shown, the fixture frame has side walls 206 that extend upwardly from the frame to an upper surface 308. The side walls 206 can be shaped substantially similar to the outer perimeter of a glass sheet G intended for use with the fixture and can extend continuously as shown.

[0056] The upper surface 308 of the fixture frame is molded or otherwise formed to correspond to or match the upper surface of the glass sheet G defined by the model or CAD data of the glass sheet G. The upper surface 308 can be set as a complete surface that extends continuously or as a solid surface and is surrounded by the side wall 206 around its perimeter. In one example, the upper surface 308 is machined into its shape based on the CAD data of the glass sheet G. In another example, the upper surface 308 can be machined or otherwise formed into its shape to substantially correspond to the center of the CAD data tolerance of the glass sheet G. In one embodiment, the upper surface 308 can be formed of or include a composite material. The upper surface 308 can be used as both a physical reference and an optical reference of the fixture 300 because the surface can be measured by both the CMM device and the system 10.

[0057] When the fixture 300 is used with a curved glass piece G, the first surface 44 of the glass piece G has a different radius of curvature than the second surface 46 of the glass piece G. In the non-limiting example shown, the first surface 44 has a larger radius of curvature than the second surface 46 of the glass piece G. The upper surface 308 of the fixture 300 has the same radius of curvature as the CAD model of the glass piece G and may represent an ideal or model first surface 44 of the glass piece G. Figure 8 A schematic cross-sectional view of a fixing device 300 with a glass pane G is shown.

[0058] A series of standoff pins 220 are provided on the fixture 300 for supporting the glass piece G above the upper surface 308 of the fixture. The standoff pins 220 extend upward from the upper surface 308 and are spaced apart from each other around the outer periphery of the upper surface 308. The standoff pins 220 provide separation between the glass piece G and the upper surface 308 of the fixture and prevent the second surface 46 of the glass piece from contacting the fixture. Since the second surface 46 of the glass piece G has a different radius of curvature than the upper surface 308 of the fixture, the standoff pins 220 may have different heights from each other, wherein the height of each standoff pin is determined using the CAD data of the glass piece G and data related to the shapes of the upper and lower surfaces of the glass piece G and the shape of the upper surface 308 of the fixture.

[0059] Note that the exact shape, size, and surface shape and contour of the actual glass piece G may differ from the CAD or other mathematical model of the glass piece G, and therefore, when the actual glass piece G is placed on the fixture 300, the actual glass piece G may not contact every support pin 220 based on the variability of the glass piece G. The support pin 220 may serve as an A-baseline for positioning the glass piece G relative to the fixture 300.

[0060] The fixture 300 may also be provided with additional base lines for positioning the edge of the patch G relative to the fixture. In the example shown, the fixture 300 has one or more B base line posts 230 and associated B base line mechanisms 232, and one or more C base line posts 240 and associated C base line mechanisms 242.

[0061] In some embodiments, upper surface 308 of fixture 300 may be formed from a material that fluoresces in response to light from a light source in system 10 , or alternatively, upper surface 308 may have a coating that fluoresces in response to light from a light source in system 10 .

[0062] In some embodiments, the upper surface 308 of the fixture 300 can be provided with one or more optical fiducials 350. The optical fiducials 350 can be used to compare the three-dimensional point cloud representing the surface data of the patch G with the mathematical or CAD model of the patch G to measure or measure the patch, or to compare the alignment data of the fixture 300 with the CMM coordinate system and the CAD model to verify the fixture alignment and coordinates and / or measure or measure the patch. The fixture 300 can be provided with one or more optical fiducials 350 for each detector or camera in the system 10. In other embodiments, the optical fiducials 350 can be located in areas of the upper surface 308 with larger radii of curvature, such as relatively flat areas.

[0063] Each optical fiducial 350 may be provided as a shape or marking on the upper surface 308 of the fixture. In one example, the optical fiducial 350 may be provided as a triangle, diamond, or the like, and may be defined by a groove machined into the surface 308 or a protrusion extending outwardly from the surface 308. Thus, the optical fiducials 350 may be detected by the CMM device so that they may be referenced relative to other baselines of the fixture 300. Additionally, since the optical fiducials 350 may be formed into the surface 308 of the fixture, the position of the optical fiducials 350 relative to the fixture surface 308 is also known. The optical fiducials 350 may also be detected by the system 10 because they may cause a change in fluorescence that may be detected by the camera(s), for example, the optical fiducial 350 may produce a higher or lower intensity fluorescence relative to an adjacent surface 308 imaged by the camera. In alternative embodiments, a coating or other optical fiducial 350 may be used.

[0064] In one example, each camera has its own optical fiducial 350. In another example, the optical fiducial 350 can be large enough to extend across the field of view of multiple cameras. In one example, for a system with one or more cameras, at least a portion of the optical fiducial 350 is positioned to be visible to all cameras 30 or detectors of the system. In another example, for a system 10 with multiple cameras and multiple optical fiducials 350, each optical fiducial can be positioned so that it is within the entire field of view of the associated camera, where the system applies additional transformations based on the known positioning of the fiducials relative to each other when creating calibrations and fixture alignments to cross-reference multiple camera data together.

[0065] In some embodiments, the fixing device 300 may be additionally provided with a fixing device similar to that described above. Figure 3 Physical references to those shown, such as a tooling sphere or other CMM surface, such as an edge or hole.

[0066] refer to Fig. 9 , shows another embodiment and Figure 1 systems and Figure 2 For simplicity, components of the fixture 400 that are the same or similar to those shown and described above with reference to the fixture 200 are given the same reference numerals.

[0067] The fixture 400 has a base frame 202 and a fixture frame 204. In the example shown, the fixture frame has a side wall 206 extending upward from the frame to an upper surface 208. The side wall can extend continuously around an open central area 210. A series of standoff pins 220 extending upward from the upper surface 208 are provided, which are configured to contact and support the glass piece on the fixture. The series of standoff pins can define an A-baseline for the fixture.

[0068] The example glass piece G0 is provided with a fixing device and supported on the support pins 220. The first surface 44 of the glass piece G0 can be used as Figure 1 System 10 and / or Figure 2 After the calibration process or method 100, the glass sheet G0 is removed and can be provided on a fixture 400 for measurement, metrology, etc. using the system 10. The first surface of the sheet G0 can be used as both a physical reference for the fixture 300 and an optical reference for the fixture 300, since the surface can be measured by both the CMM device and the system 10. In other examples, in addition to the optical reference provided by the first surface 44 of the glass sheet G0 itself, the glass sheet G0 can also be etched or otherwise provided with an optical reference, such as described above with respect to Figure 7 and Figure 8 An optical reference 350 is described.

[0069] In further examples, a fixture having a reference, such as reference 250 and / or reference 350, may be provided for use with a fixture for use with the example glass piece G0, for example by attaching a reference to Figure 7 and Figure 8 The features of the fixing devices 200, 300 described are similar to those of Fig. 9 400 is combined with the fixture 400 described above. For clarity, in this example, the fiducials 250, 350 may also be referred to as camera optical fiducials to distinguish them from the optical fiducials provided by the first surface 44 of the glass piece G0 itself. For systems 10 with more than one camera 30, an optical fiducial 250, 350 may be provided for each camera, such that there is at least one fiducial 250, 350 for each camera 30. When used in conjunction with the glass piece G0, the optical fiducials may provide an additional feature for the alignment algorithm to reference and provide an overall solution with greater speed, accuracy, and / or precision.

[0070] The fixture 400 may also be provided with additional baselines, in the example shown the fixture has a pair of B-baseline posts 230 , associated B-baseline mechanisms 232 , a C-baseline post 240 , and associated C-baseline mechanisms 242 .

[0071] The fixture may additionally be provided with a physical reference 260, such as a tooling sphere 260 or other CMM surface, such as an edge or hole. The glass piece GO is positioned relative to the known tooling sphere position on the fixture using the baseline and standoff pins on the fixture 400.

[0072] Return to reference Figure 2 , steps 106-114 illustrate a portion of a sub-method 104 for verifying a fixture 200, 300, 400 or for associating, relating, and transforming between fixture coordinates, calibration stage coordinates, CMM coordinates, and CAD coordinates. For simplicity, the fixture 14 is generally used below with respect to the method steps, which fixture 14 may refer to the use of any of the fixtures 200, 300, or 400. In addition, the steps described for use with one of the fixtures 200, 300, 400 and the system 10 may additionally be applied to other fixtures disclosed herein.

[0073] When the fixture 14 is provided at step 106, a mathematical model of the glass piece G can be provided in a model or CAD coordinate system. For the fixture 200, the position of the fixture tool sphere 260 can also be provided in CAD coordinates, for example as a fixture tool sphere coordinate system. The relationship between the CAD coordinate system and the fixture tool sphere coordinate system is determined.

[0074] For fixtures 300 and 400, the mathematical model of glass piece G includes and corresponds to upper surface 308 of the fixture or upper surface of glass piece G0, respectively. In another example, a mathematical model or file can be generated that includes the mathematical model of the upper surface of piece G0 or upper surface 308 in CAD coordinates and also includes any tooling sphere locations on the fixture and glass baselines.

[0075] At step 108, the CMM device may be used to calibrate the fixture 14. For the fixture 200, the CMM device has a CMM coordinate system. The CMM device measures the physical reference 260 of the fixture and / or any other CMM surface on the fixture. The CMM device also measures any physical reference 270 on the optical reference. The CMM device provides an optical reference CMM surface coordinate system. The CMM device may additionally provide a fixture CMM coordinate system. Both the optical reference CMM surface coordinate system and the fixture CMM coordinate system are referred to below. FIG. 6A to FIG. 6D The fixture 200 may be measured using a CMM device to determine the positions of the first and second series of physical datums and the optical datum of the fixture in CMM coordinates.

[0076] For the fixture 300, the upper surface 308 can be measured using a CMM device to verify that the shape of the upper surface 308 corresponds to the first surface 44 of the glass sheet G in the CAD data. The CAD data can be positioned relative to the baseline and the reference on the fixture 300 known in the measured CMM data. Data in a file, for example, can be generated, which includes the CAD data, the calibration surface 308, the optical reference 350, and any other baseline positions of the reference CMM coordinate system. This can achieve a unified coordinate system between the CAD and CMM coordinate systems. In other examples, the upper surface 308 of the fixture 300 can be measured without using a CMM device, and step 108 can be omitted.

[0077] For fixture 400, the glass sheet G0 is measured using the CMM equipment to determine the shape of sheet G0 and reference sheet G0 to any tooling spheres of fixture 400. Data, such as in a file, may be generated that includes first surface 44 of sheet G0, any optical fiducials on sheet G0, and any other baseline positions referenced to the CMM coordinate system.

[0078] At step 110, the fixture 14 is positioned within the system 10. The fixture is located at a known position on the fixed conveyor 12, and the fixture is imaged using the camera 30 or other detector in the system 10. For example, when the light source is a laser and with the fixture 200, the fixture 14 can be imaged without operating the system light source 40. Alternatively, the fixture 14 can be imaged while the light source 40 is operating (e.g., when using the fixture 300 or 400).

[0079] The fixture 200 can be positioned in the system 10 without the glass sheet G, and can be positioned at a height that the fixture 200 would be positioned in the system with the sheet G.

[0080] Fixture 300 may be positioned in system 10 without glass sheet G, and may be raised in system 10 so that upper surface 308 is located at a height corresponding to the height of the upper surface of glass sheet G when glass sheet G is present on fixture 300 in system 10. This places fixture surface 308 at the same height or z-position as the upper surface of glass sheet G when glass sheet G is measured on system 10. Note that the height or position of upper surface 308 is therefore different between the calibration method and when inspecting, measuring, or metrology sheet G.

[0081] Fixture 400 may be positioned in the system with example sheet G0 and at a height at which fixture 200 is positioned in the system with sheet G to be measured or tested. Note that for inspection, measurement, or metrology procedures, sheet G0 is removed and replaced with sheet G. Sheet G0 may be stored for later use, such as to recalibrate fixture 400.

[0082] For a fixture used with the combined optical references 250, 350 and example glass sheet G0, as described above, the fixture can be positioned in the system a first time without the glass sheet G0 to be measured and tested, and then positioned in the system a second time with the glass sheet G0 to be measured or tested, or vice versa.

[0083] Figure 5A A schematic diagram of a fixture 14 is shown with one camera 30 or two cameras 30 positioned on either side of the fixture, such as upstream and downstream of the fixture. The fixture can be positioned in the system so that the optical reference is completely within the field of view of all cameras, as described above. Figure 5A The fixture 200 is used by way of non-limiting example.

[0084] Figure 5BA schematic diagram of a fixture 14 is shown with two cameras positioned on the same side of the fixture, such as both upstream or both downstream. The fixture can be positioned in the system so that the optical reference is completely within the field of view of both cameras, as described above. Figure 5B The fixture 200 is used by way of non-limiting example.

[0085] Figure 5C A schematic diagram of a fixture 14 and multiple cameras 30 having multiple optical fiducials 350 is shown, wherein each camera has at least one optical fiducial completely within its field of view and the positions of the optical fiducials relative to each other are otherwise known. Figure 5C The fixture 300 is used by way of non-limiting example.

[0086] Return to reference Figure 2 At step 112, the fixture and any optical references are imaged using the detector(s) 30 in the system 10. The system 10 may then create an optical reference coordinate system, and may additionally create an optical reference CMM surface coordinate system.

[0087] For fixture 200, optical fiducial(s) 250 are imaged using camera 30 to provide optical calibration of the fixture in the absence of glass sheet G and to position the optical fiducial in the system 10 coordinate system measured and referenced to the optical data and camera, e.g., as an optical fiducial coordinate system. The optical fiducial may be positioned and optically calibrated once or each time it is positioned on the conveyor.

[0088] The image data may be processed to reduce noise, such as by applying a threshold to the image, normalizing the image, transforming the image using a fast Fourier transform, filtering the image, and the like.

[0089] The computer system creates an optical fiducial coordinate system based on the optical data calibration table. The dimensions of the checkerboard squares or other features on the optical fiducial 250 are known to provide calibration in the x and y directions. The calibration in the z direction is based on the relationship between the x and y calibrations and accurately locates the optical fiducial and fixture in the image and creates an optical coordinate system. FIG. 6A to FIG. 6C The example shown describes the details of creating an optical coordinate system from an image.

[0090] According to one example, a chessboard or other optical fiducial 250 may be applied to a substrate on a fixture, such as as a decal or the like. In other examples, the chessboard may be printed directly onto the substrate, or the substrate may be formed or otherwise provided with the optical fiducial 250. Depending on how the optical fiducial is applied to the substrate, the position of the optical fiducial or chessboard on the substrate itself may vary, making it necessary to determine the position of the optical fiducial 250 relative to the fixture. Therefore, the optical fiducial 250 is also provided with an associated physical fiducial 270. The physical fiducial 270 may be formed before or after the optical fiducial 250 is applied to the fixture. At step 112, the image of the optical fiducial 250 also includes imaging the physical fiducial 270. The image analysis may locate the physical fiducial 270 in the optical fiducial CMM surface coordinate system, and locate the optical fiducial 250 in the optical fiducial coordinate system, wherein both coordinate systems are referenced to the image space. The image analysis may locate the physical fiducial 270 or marker based on the visual features of the physical fiducial 270.

[0091] For the fixture 300 and step 112, the fixture 300 can be imaged while the system light source 40 or laser is operated. The upper surface 308 of the fixture can be formed of a material that fluoresces in response to light from the laser, or alternatively, the upper surface 308 can be painted or coated so that it fluoresces in response to the light source. Each camera 30 can image its corresponding associated reference 350. Each camera 30 provides associated image data and point clouds for an associated viewing area on the upper surface 308. The system 10 provides optical calibration of the fixture 300 without the glass sheet G, and positions the upper surface 308 and (one or more) optical references 350 in the system 10 coordinate system measured and referenced to the optical data and cameras, for example as an optical reference coordinate system.

[0092] The fixture 400 may also be imaged while the system light source 40 or laser is operated at step 112. The upper surface of the patch G0 fluoresces in response to the light from the laser, and each camera 30 provides associated image data and point clouds for an associated viewing area in the system 10. The system 10 provides optical calibration of the fixture 400 using the measured and referenced optical data and example patch G0 in the system 10 coordinate system of the cameras (e.g., as an optical reference coordinate system).

[0093] For a fixture that uses a combination of optical fiducials 250, 350 and an example glass sheet G0 to provide calibration, the optical fiducials 250, 350 may be imaged as described above to provide optical calibration of the fixture in the absence of the glass sheet and the optical fiducials may be positioned in the system 10 optical fiducial coordinate system in a first data set, which may include image data from a single camera or data from multiple cameras stitched together using an appropriate transformation. The example glass sheet G0 is positioned on the fixture and the fixture is imaged relative to the example glass sheet G0 as described above to provide optical calibration of the sheet G0 in the system 10 optical fiducial coordinate system in a second data set. Image data from optical fiducials (e.g., fiducials 250, 350) may be used to generate transformations to align and combine data from multiple cameras in the system 10 optical fiducial coordinate system. Image data from the surface of the example glass sheet G0 may be used to generate transformations (one or more) to associate the system 10 optical fiducial coordinate system with a CAD coordinate system as described below, for example by associating the optical coordinate system with CMM data and coordinate systems. At step 114, the optical reference coordinate system may be associated with the CMM coordinates and / or the optical reference CMM coordinate system. A linear algebraic transformation may be applied that produces a transformation matrix that relates the CMM-determined optical reference coordinates to the optically-determined optical reference coordinates and the CAD coordinate system, as described below with reference to FIG. 6A to FIG. 6D as described in the examples.

[0094] Then, at step 130, the system 10 is ready to begin inspecting the glass sheet G on the fixture and measuring or metering the surface by comparing the point cloud matrix defining the surface with the CAD data representing what the surface of the sheet G should be. The glass sheet G is scanned using the subsystem 16 to create a point cloud or matrix of the surface of the glass sheet. The system uses the calibration and transformation matrix between the optically determined optical reference coordinate system and the CAD coordinate system to locate the sheet surface point cloud relative to the CAD data in the CAD coordinate system. The CMM data and coordinates, as well as any data of interest from the probe, the support, the sheet G surface cloud, etc., and the known position of the fixture in the CAD coordinate system, allow the correlation or transformation from the optically determined coordinates to the CAD coordinates to be obtained. These transformations align different data from different coordinate and measurement systems for comparison purposes.

[0095] Once the fixture has been verified using the CMM equipment, the fixture calibration process can continue and omit step 108 because the transformation or correlation between the optical coordinates and the CMM coordinates is already known.

[0096] In another example, the calibration process and method 100 may continue and omit step 108 and any use of CMM data and coordinates, where a direct transformation or correlation between optical coordinates and CMM coordinates based on an optical reference is built into known, precise and accurate positions in the fixture.

[0097] FIG. 6A to FIG. 6D Various methods for associating optical coordinates, CMM coordinates, and CAD coordinates are shown. The method may be implemented in whole or in part by the control system 18, 20 of the system 10. Alternatively, a portion of the method may be implemented by another system (e.g., a CMM), with the CMM coordinate system and the transformation to CAD coordinates being input into a memory connected to the control system 18, 20 of the system 10. FIG. 6A to FIG. 6D The method shown in may be embodied in other forms utilizing other transformations between various coordinate systems based on available data and systems. FIG. 6A to FIG. 6D The example shown in is intended to illustrate a method of associating a coordinate system for use with system 10. In one non-limiting example, FIG. 6A to FIG. 6C The method shown in can be used with the fixture 200, 300 or 400. In another non-limiting example, Fig. 6A , Figure 6B and Fig.6D The method shown in FIG. 4 may be used with the fixing devices 300 , 400 .

[0098] Fig. 6A A coordinate system is shown derived from three non-collinear points P1, P2, and P3 according to a non-limiting example. The three non-collinear points can represent three different points measured using a CMM and in a CMM coordinate system from a physical reference 260 (e.g., a tool ball or other CMM surface) on a fixture 14. In order to convert the three non-collinear points to a three-dimensional coordinate system, such as a Cartesian coordinate system, the controller selects P1 as the origin. The controller then defines the positive X-axis as a [unit] vector from P1 to P2. The controller defines the Y-axis as a [unit] vector perpendicular to the already defined X-axis and in the plane defined by P1, P2, and P3. Finally, the controller calculates the Z-axis as the cross product of the previously defined X-axis and Y-axis. In other examples, the controller can use other conventions to define a coordinate system from three points, as long as the conventions are consistent, and in addition, other coordinate systems can be used.

[0099] Figure 6B 1 shows a coordinate system derived from an optical reference (e.g., a chessboard, other calibration stage, or fixture surface) according to one non-limiting example. The coordinate system can be derived as an optical coordinate system by a control system of system 10 based on data from (one or more) detectors or cameras of system 10. In one non-limiting example, the origin defined by the controller is one of the interior corners of the chessboard, such as Figure 6BFor a Cartesian coordinate system, the controller may align the X-axis along one edge of the chessboard and the Y-axis along the other edge so that the chessboard or optical fiducial lies in the XY plane. The controller then calculates the Z-axis as the cross product of the X-axis and the Y-axis. In other examples, the controller may use other conventions to define a coordinate system from three points, and as long as the convention is consistent, other coordinate systems may be used.

[0100] Figure 6C A schematic diagram of a series of transformations that can be used to convert between various coordinate systems for use with the system 10 and method 100 according to the present disclosure is shown. According to one example, the transformation between two given coordinate systems can be provided by a transformation matrix, equation, etc. calculated via linear algebra. The transformation between the two coordinate systems can account for a translation from a first coordinate system to a second coordinate system, a rotation of the first coordinate system to the second coordinate system, and / or a scaling of the first coordinate system relative to the second coordinate system via the transformation matrix between the two respective coordinate systems.

[0101] According to the present example, the system 10, fixtures 14, 200, 300, 400 and method 100 use five coordinate systems, but other numbers of coordinate systems are possible based on the data available to the system 10. The five coordinate systems are Figure 6C , where the transformations and transformation matrices between them are schematically shown. According to this example, the five coordinate systems are as follows:

[0102] A CAD or model coordinate system is provided that can represent the glass sheet G in a product, end use, or other configuration.

[0103] A CMM coordinate system is provided which represents the default coordinate system used and measured by a CMM device.

[0104] A physical reference coordinate system is provided which represents the coordinate system of a physical reference 260 by three points given in CAD coordinates, for example a tooling sphere of the fixture 200 modeled or positioned within the CAD model or space.

[0105] An optical reference coordinate system is provided, such as a checkerboard coordinate system, which represents the coordinate system of the optical reference 250 on the fixture measured using (one or more) detectors or cameras of system 10, or the coordinate system of the calibration surface and optical reference 350 on the fixture, or the coordinate system of the surface of the example glass piece G0.

[0106] An optical reference CMM surface coordinate system is provided, which represents a coordinate system defined by three points, or can represent a calibration surface on a fixture and an optical reference 350, or the surface of an example glass sheet G0, wherein the three points are represented by physical references 270 (e.g., edges, holes, or other reference marks in a checkerboard plane) measured using (one or more) detectors or cameras of the system 10 on the optical reference.

[0107] As a non-limiting example, transformations and transformation matrices may be provided between the above reference coordinate systems as follows:

[0108] A transformation T0 from the CAD system to the fixture physical reference system may be provided. Since the tooling sphere or other physical reference 260 has been defined in CAD coordinates in this example, this can be determined directly without the need for mathematical transformations.

[0109] A transformation T1 may be provided to transform a physical reference coordinate system into a CMM coordinate system by measuring a tooling sphere or other fixture physical reference 260 in CMM coordinates via the CMM apparatus.

[0110] T0 and T1 may be used to provide and derive a transformation T2 to provide a conversion or transformation from the CAD coordinate system to the CMM coordinate system.

[0111] A transformation T3 may be provided to transform the optical reference coordinate system to the optical reference CMM surface coordinate system, for example to relate the coordinate system of a chessboard to the coordinate system of a physical reference 270 on the chessboard. In one example, the transformation T3 may be determined via measurements or data from the detector(s) or camera(s) of the system 10, since it involves only a two-dimensional transformation, i.e., the XY plane of the optical reference or chessboard. In order to determine the transformation, it may be necessary to absolutely align the optical reference of the fixture with the X and Y axes.

[0112] By measuring the physical datum 270 or CMM surface on the optical datum in CMM coordinates via the CMM apparatus, a transformation T4 may be provided as a transformation from the optical datum CMM surface coordinate system to the CMM system.

[0113] T2 and T4 may be used to provide and derive a transformation T5 to provide a conversion or transformation from the optical reference CMM surface coordinate system to the CAD coordinate system.

[0114] Finally, a transformation T6 may be provided and derived from T3 and T5 to provide a conversion or transformation from the optical reference coordinate system to the CAD coordinate system.

[0115] Using the calibration stage coordinate system related to the CAD coordinate system, a later point cloud or three-dimensional map of the surface of the patch G from the camera can be accurately and precisely positioned in the CAD model for measurement and metrology.

[0116] Computer 20 receives image data from camera 30. Computer 20 uses the data from the image to form a matrix or point cloud, such as cells in the matrix associated with locations on surface 44 of the glass sheet, or as an array of points in the point cloud associated with locations on surface 44 of the glass sheet. The control system can perform various de-noising steps as post-processing on the point cloud. System 10 sets or positions the three-dimensional map of the surface of glass sheet G determined from the point cloud relative to the coordinate system or calibration surface of the calibration stage and the optical reference. This then allows the three-dimensional map of the surface of glass sheet G to be transformed into a CAD model using a transformation matrix such as T6 so that the measured surface map can be compared with the CAD model, such as for measurement, metrology or other inspection functions.

[0117] The CAD model may include a mathematical model or a gauge model of the glass piece G in a CAD coordinate system. The gauge model may be provided using a computer-aided design (CAD) model and / or data, or other mathematical models or representations of size or shape. The control system may select the appropriate CAD model, gauge model, and transformation based on identification of the fixture using a visual indicator on the calibration stage or fixture.

[0118] Fig.6D Another schematic diagram shows a series of transformations that can be used to convert between various coordinate systems for use with the system 10 and method 100 according to the present disclosure, and can be used instead of Figure 6C The transformation shown. Fig.6D A system 10 with four detectors or cameras is shown, but it is contemplated that Fig.6D It can be modified for use with a system 10 having any number of detectors, including one detector, less than four detectors, or more than four detectors.

[0119] According to one example, the transformation between two given coordinate systems can be provided by a transformation matrix, equation, etc. calculated via linear algebra. Via the transformation matrix between the two corresponding coordinate systems, the transformation between the two coordinate systems can account for the translation from the first coordinate system to the second coordinate system, the rotation of the first coordinate system to the second coordinate system, and / or the scaling of the first coordinate system relative to the second coordinate system.

[0120] According to the present example, the system 10, fixture 14, 300, 400 and method 100 use two or three coordinate systems, but other numbers of coordinate systems are possible based on the data available to the system 10. CMM and optical reference coordinate systems are Fig.6D , where the transformations and transformation matrices therebetween are schematically shown by way of non-limiting example.

[0121] A transformation T7 may be provided or derived to provide a conversion or transformation from the CAD coordinate system to the CMM surface coordinate system. In other examples, transformation T7 may be omitted. The calibration surfaces and optical fiducials of the fixtures 300, 400 may be measured with a CMM apparatus so that they are directly referenced to the CMM surface coordinate system.

[0122] One or more transformations T8 may be provided to relate the optical reference coordinate system to the model coordinate system. A model of the glass sheet may be provided in the model coordinate system based on CAD data or based on CMM data of calibration surface 308 or sheet surface G0 and any other reference measurable by the CMM system. In further examples, transformations T7 and T8 are used to relate the optical reference coordinate system to the model coordinate system.

[0123] One or more transformations T8 may transform the optical reference coordinate system to the CMM surface coordinate system, for example, to relate the coordinate systems of the calibration surface and the optical reference to the coordinate system of the physical reference 270 on the chessboard. In one example, the transformation T8 may be determined via measurements or data from the detector(s) or camera(s) of the system 10 and the known positions of the detector 30 and the light source 40.

[0124] For example, the computer 20 can determine or calculate points along the model line based on the image data of the visible fluorescent line on the calibration surface of the fixture. Therefore, the computer 20 calculates the points of the model line as a series of coordinates or (x, y) data sets. These (x, y) data sets are then input by the computer 20 into the associated cells in the matrix or point cloud. Each data set can include an (x, y) value corresponding to the position of the calibration surface in the xy plane.

[0125] The position of the laser, the position of the camera, and the first and second coordinates can be used to triangulate a third coordinate (e.g., a (z) coordinate) of the calibration surface and store the third coordinate in a matrix or point cloud. The computer 20 can calculate the z value of the set of (x, y) coordinates associated with the z position of each set of coordinates on the calibration surface. The computer enters the (z) value into the associated cell with the corresponding (x, y) coordinate in the matrix to complete the map of the calibration surface visible to the camera 30. A method of determining an (x, y, z) data set or point cloud from a surface using the system 10 is further described in PCT patent application serial number PCT / US19 / 43180, and according to one example, the method can be used herein to determine the (x, y, z) coordinates or data set of the calibration surface of the fixture.

[0126] Once the system 10 determines the calibration surface point cloud in the optical coordinate system, the computer 20 links the optically measured calibration surface data or calibration surface point cloud data to the CMM data or CAD data of the calibration surface of the fixture. According to one example, the optically measured calibration surface data is aligned with the CMM data using a surface fitting algorithm, and a transformation T8 is created. Optical fiducials set on the calibration surface of the fixture can further help locate the optically measured calibration surface data and fit it to the CMM data, especially in flatter areas. Transformation T8 can translate and / or rotate the point cloud from each camera 30 to the associated CMM or CAD data of the same area of ​​the sheet.

[0127] In a further example, if the CMM data is identical to the CAD data, then a surface fitting algorithm may be used to directly align the optically measured calibration surface data with the CAD data, otherwise transformation T7 may be applied.

[0128] In the example shown, a separate transformation T8 is determined for each detector or camera 30, which are shown as T8a, T8b, T8c and T8d. The transformations T8a-d can be maintained as separate transformations associated with different areas of the calibration surface and the sheet. Therefore, they can be easily regenerated because they do not need to be related to or combined with each other. According to one example, when the system 10 determines an invariant metric (e.g., optical reflectivity) for the sheet G on the fixture 300, 400, the system 10 uses separate transformation matrices T8a-d. According to another example, when the system 10 is used for non-contact measurement of the sheet G on the fixture 300, 400, the transformation matrices T8a-d can be combined into a single transformation matrix T8* for use with the system 10. Adjacent fields of view of the cameras may overlap each other.

[0129] The use of system 10 and fixtures 300, 400 can easily reproduce the transformation T8 for various positions of the fixture or sheet in system 10, such as at different tilt angles. In addition, the use of fixtures 300, 400 allows the transformation T8 to be easily reproduced if components of system 10 are reconfigured, or to account for drift or errors of system 10 over time.

[0130] Using the optical reference coordinate system related to the CMM and / or CAD coordinate system, the post point cloud or three-dimensional map of the surface of the patch G from the camera can be accurately and precisely positioned in the CAD model or other model for measurement and metrology using the transformation matrix T8.

[0131] When the sheet G is positioned on the fixture 300, 400 in the system 10, the computer 20 receives image data from each camera 30. The computer 20 uses the data from the images to form a matrix or point cloud, such as a cell in the matrix associated with a location on the surface 44 of the glass sheet, or as an array of points in the point cloud associated with a location on the surface 44 of the glass sheet. The control system can perform various de-noising steps as post-processing on the point cloud. The system 10 sets or positions the three-dimensional map of the surface of the glass sheet G determined from the point cloud relative to the coordinate system of the calibration surface and (one or more) optical references. This then allows the three-dimensional map of the surface of the glass sheet G to be transformed into a CAD or other model using the transformation matrix T8, or compared with CMM data, so as to compare the measured surface map with the CAD model, such as for measurement, metrology or other inspection functions.

[0132] The CAD model may include a mathematical model or metrology model of the glass sheet G in the CAD coordinate system. The calibration surface of the fixture 300 or the upper surface of the example sheet G0 may be based on or referenced to the CAD model so that they correspond directly to each other or have a known relationship based on T7. The metrology model may be provided using a computer-aided design (CAD) model and / or data, or other mathematical model or representation of size or shape. The control system may select an appropriate CMM or CAD model, metrology model, and transformation based on identification of the fixture using one or more visual indicators on the fixture 300, 400.

[0133] The method 100 provides for positioning and calibrating the glass sheet G using non-contact metrology of the surface and the glass sheet G, and using the resulting map of the sheet determined by the system compared to other metrology models or CAD in other coordinate systems. The fixture and associated calibration and inspection methods allow for accurate and precise in-line monitoring and inspection of the part, and allow for quick and easy metrology of a range of different parts, or use of multiple metrology models. Furthermore, non-contact metrology via the method 100 provides for reduced time and expense associated with metrology of the part, because the metrology model can be easily created, changed or updated using CAD data and updates to calibration transforms, and does not require the use of precision measurement metrology tools specific to the part for contact metrology.

[0134] In other embodiments, the fixture and method can be used with an optical system to calibrate a system for optically inspecting objects other than a glass sheet G. In one non-limiting example, an optical system having a laser that emits light at another wavelength (e.g., a visible wavelength) can be used to scan an object having a diffuse surface. The optical system uses one or more cameras to determine a three-dimensional surface map of the diffuse surface using the method described above.

[0135] Aspects of the present disclosure.

[0136] Aspect 1. An optical inspection system has a fixture for supporting a glass sheet, with an optical reference disposed on the fixture. An ultraviolet laser and associated optical devices form a planar sheet-shaped laser beam directed toward the glass sheet, wherein the planar sheet-shaped laser beam intersects the surface of the glass sheet, thereby causing the surface of the glass sheet to fluoresce and form visible wavelength lines on the surface. A camera has an image sensor for detecting the optical reference and for detecting visible wavelength lines across at least a portion of the width of the sheet. A control system is configured to (i) image the optical reference on the fixture, (ii) define an optical reference coordinate system from the imaged optical reference, (ii) receive a mathematical model of the glass sheet in a model coordinate system, and (iii) relate the optical reference coordinate system to the model coordinate system via at least one transformation.

[0137] Aspect 2. The system of any of Aspect 1 or subsequent aspects, wherein the control system is further configured to (i) receive image data indicating a visible wavelength line from a camera, (ii) analyze the data from the camera to determine a first coordinate and a second coordinate in a series of coordinates associated with the line, (iii) triangulate a third coordinate associated with each of the first coordinate and the second coordinate in the series of coordinates, and (iv) create a three-dimensional map of the surface of the glass sheet based on the series of coordinates.

[0138] Aspect 3. The system according to any preceding or subsequent aspect, wherein the control system is further configured to transform the three-dimensional map via at least one transformation, the three-dimensional map being associated with the model coordinate system.

[0139] Aspect 4. The system of any preceding or subsequent aspect, wherein the control system is further configured to output a metric indicative of a measurement of the glass piece in response to comparing the three-dimensional map to the mathematical model in the model coordinate system.

[0140] Aspect 5. The system of any preceding or subsequent aspect, wherein the control system is further configured to determine the metric as a simulated optical reflectivity of the surface using a comparison of the three-dimensional map of the surface with the mathematical model in the model coordinate system.

[0141] Aspect 6. The system of any preceding or subsequent aspect, wherein the control system is further configured to use the three-dimensional map of the surface to determine a metric for metering the glass sheet.

[0142] Aspect 7. The system of any of the preceding or subsequent aspects, wherein the control system is further configured to receive a series of data indicating a series of visible wavelength lines measured from a camera across the width of the sheet, each line corresponding to a different location along the surface of the glass sheet. The control system is further configured to analyze each line in the series of visible wavelength lines to determine a first coordinate and a second coordinate in a series of coordinates associated with each line, triangulate a third coordinate associated with each of the first coordinate and the second coordinate in each of the series of coordinates, and create a three-dimensional map of the surface of the glass sheet from each of the series of coordinates.

[0143] Aspect 8. The system of any preceding or subsequent aspect, wherein the wavelength of the ultraviolet laser is selected to not transmit through the glass sheet.

[0144] Aspect 9. The system of any preceding or subsequent aspect, wherein the fixture has a first series of physical references, the first series of physical references having at least three coordinates in the model coordinate system.

[0145] Aspect 10. The system of any preceding or subsequent aspect, wherein the first series of physical references of the fixture are provided by a calibration surface shaped to correspond to at least a portion of a surface of the glass sheet.

[0146] Aspect 11. The system according to any preceding or subsequent aspect, wherein the calibration surface additionally forms an optical reference.

[0147] Aspect 12. The system according to any preceding or subsequent aspect, wherein the fixture has at least one optical fiducial positioned on the calibration surface.

[0148] Aspect 13. The system according to any preceding or subsequent aspect, wherein the at least one optical fiducial additionally provides at least one physical fiducial.

[0149] Aspect 14. The system according to any preceding or subsequent aspect, wherein the control system is further configured to determine or derive a transformation from the optical reference coordinate system to the model coordinate system.

[0150] Aspect 15. The system of any preceding or subsequent aspect, wherein the fixture has a calibration surface shaped to correspond to at least a portion of a surface of a glass sheet provided by example glass sheet G0 to provide a first optical reference.

[0151] Aspect 16. The system of any preceding or subsequent aspect, wherein the fixture has a camera optical reference associated with each camera.

[0152] Aspect 17. A system according to any of the preceding or subsequent aspects, wherein the control system is further configured to image the camera optical fiducial to relate the cameras via at least one other transformation, and to image the calibration surface separately as an optical fiducial to relate the optical fiducial coordinate system to the model coordinate system via at least one transformation.

[0153] Aspect 18. The system of any preceding or subsequent aspect, wherein the control system is configured to determine or receive a transformation relating a fixture physical reference coordinate system to a model coordinate system, the transformation being determined using a first series of physical references from the fixture.

[0154] Aspect 19. The system of any preceding or subsequent aspect, wherein the optical fiducial further defines a second series of physical fiducials. The control system is configured to image the second series of physical fiducials and relate the second series of physical fiducials to the optical fiducial coordinate system.

[0155] Aspect 20. A system according to any of the preceding or subsequent aspects, wherein the control system is configured to determine or receive a transformation relating a physical reference coordinate system of the fixture to a physical reference coordinate system of the optical reference, the transformation being determined using a first series of physical references from the fixture and a second series of physical references from the optical reference.

[0156] Aspect 21. The system of any preceding or subsequent aspect, wherein the control system is further configured to determine or receive a transformation relating the fixture physical reference coordinate system to the second series of physical references.

[0157] Aspect 22. The system according to any preceding or subsequent aspect, wherein the control system is further configured to determine or derive a transformation from the model coordinate system to the second series of physical references.

[0158] Aspect 23. The system according to any preceding or subsequent aspect, wherein the control system is further configured to determine or derive a transformation from the optical reference coordinate system to the model coordinate system.

[0159] Aspect 24. The system of any preceding or subsequent aspect, wherein the fixture has a series of supports for supporting the glass piece, a first baseline for positioning the glass piece relative to the fixture, and a second baseline for positioning the glass piece relative to the fixture.

[0160] Aspect 25. A method of using a non-contact optical inspection system is provided. A fixture is provided for supporting a glass sheet, the fixture being provided with an optical fiducial. The optical fiducial on the fixture is imaged via a camera in an inspection assembly. An optical fiducial coordinate system is defined via a control system by analyzing the imaged optical fiducial. A mathematical model of the glass sheet in a model coordinate system is received via the control system. The optical fiducial coordinate system is related to the model coordinate system via at least one transformation via the control system.

[0161] Aspect 26. A method according to any of the preceding or subsequent aspects, wherein a planar sheet-shaped laser beam is formed by an ultraviolet laser and associated optical devices of the inspection assembly and directed toward the surface of the glass sheet on the fixture. The surface of the glass sheet is excited at the intersection of the planar sheet-shaped laser beam and the surface of the glass sheet to form visible wavelength lines on the surface of the glass sheet. The visible wavelength lines are imaged using a camera. A first coordinate and a second coordinate in a series of coordinates associated with the visible wavelength lines are determined by analyzing imaging data from the camera. A third coordinate associated with each of the first coordinate and the second coordinate in the series of coordinates associated with the visible wavelength lines is determined by triangulation. A three-dimensional map of the surface of the glass sheet is created based on the series of coordinates.

[0162] Aspect 27. The method of any of the preceding or subsequent aspects, wherein the three-dimensional map is transformed via at least one transformation to relate the three-dimensional map to a model coordinate system. The three-dimensional map is compared with a mathematical model of the surface in the model coordinate system to calculate an invariant metric. The invariant metric is output.

[0163] Aspect 28. The method according to any preceding or subsequent aspect, wherein at least one transformation is provided as at least one transformation matrix.

[0164] Although exemplary embodiments are described above, these embodiments are not intended to describe all possible forms of the present invention and / or the present disclosure. On the contrary, the words used in the specification are descriptive rather than restrictive words, and it should be understood that various changes can be made without departing from the spirit and scope of the present invention. In addition, the features of various implementation embodiments can be combined to form other embodiments of the present invention.

Claims

1. An optical inspection system, comprising: a fixture for supporting the glass sheet, the fixture having an optical reference disposed thereon; an ultraviolet laser and associated optics that form a planar sheet-shaped laser beam directed toward the glass sheet, wherein the planar sheet-shaped laser beam intersects the surface of the glass sheet, thereby causing the surface of the glass sheet to fluoresce and form visible wavelength lines on the surface; a camera having an image sensor for detecting the optical fiducial and for detecting visible wavelength lines spanning at least a portion of the width of the sheet; as well as A control system configured to (i) image the optical fiducial on the fixture, (ii) define an optical fiducial coordinate system from the imaged optical fiducial, (iii) receive a mathematical model of the glass piece in a model coordinate system, and (iii) relate the optical fiducial coordinate system to the model coordinate system via at least one transformation.

2. The system of claim 1 , wherein the control system is further configured to (i) receive image data indicating the visible wavelength line from the camera, (ii) analyze the data from the camera to determine a first coordinate and a second coordinate in a series of coordinates associated with the line, (iii) triangulate a third coordinate associated with each of the first coordinate and the second coordinate in the series of coordinates, and (iv) create a three-dimensional map of the surface of the glass sheet based on the series of coordinates. 3 . The system of claim 2 , wherein the control system is further configured to transform the three-dimensional map via the at least one transformation so that the three-dimensional map is associated with the model coordinate system.

4. The system of claim 3, wherein the control system is further configured to output a metric indicative of a measurement of the glass sheet in response to comparing the three-dimensional map to the mathematical model in the model coordinate system.

5. The system of claim 4, wherein the control system is further configured to determine the metric as a simulated optical reflectivity of the surface using the three-dimensional map of the surface in comparison with the mathematical model in the model coordinate system.

6. The system of claim 4, wherein the control system is further configured to use the three-dimensional map of the surface to determine a metric for metering the glass sheet.

7. The system of claim 4, wherein the control system is further configured to receive a series of data indicating a series of visible wavelength lines measured across the width of the sheet from the camera, each line corresponding to a different location along the surface of the glass sheet; and Wherein the control system is further configured to analyze each line in the series of visible wavelength lines to determine a first coordinate and a second coordinate in a series of coordinates associated with each line, triangulate a third coordinate associated with each of the first coordinate and the second coordinate in each of the series of coordinates, and create the three-dimensional map of the surface of the glass sheet based on each of the series of coordinates.

8. The system of claim 7, wherein the wavelength of the ultraviolet laser is selected so as not to be transmitted through the glass sheet.

9. The system of claim 1, wherein the fixture has a first series of physical references having at least three coordinates in the model coordinate system.

10. The system of claim 9, wherein the first series of physical references of the fixture are provided by calibration surfaces shaped to correspond to at least a portion of the surface of the glass sheet. The system of claim 10 , wherein the calibration surface additionally forms an optical reference.

12. The system of claim 10, wherein the fixture has at least one optical fiducial positioned on the calibration surface.

13. The system of claim 12, wherein the at least one optical reference additionally provides at least one physical reference.

14. The system of claim 10, wherein the control system is further configured to determine or derive a transformation from the optical reference coordinate system to the model coordinate system.

15. The system of claim 9, wherein the fixture has a calibration surface shaped to correspond to at least a portion of a surface of a glass sheet provided by example glass sheet G0 to provide a first optical reference.

16. The system of claim 15, wherein the fixture has a camera optical reference associated with each camera.

17. A system according to claim 16, wherein the control system is further configured to image the camera optical reference to associate the cameras via at least one other transformation, and to image the calibration surface separately as an optical reference to associate the optical reference coordinate system with the model coordinate system via at least one transformation.

18. The system of claim 9, wherein the control system is configured to determine or receive a transformation relating a fixture physical reference coordinate system to the model coordinate system, the transformation determined using the first series of physical references from the fixture.

19. The system of claim 9, wherein the optical fiducials further define a second series of physical fiducials; and Wherein the control system is configured to image the second series of physical fiducials and associate the second series of physical fiducials with the optical fiducial coordinate system.

20. The system of claim 19, wherein the control system is configured to determine or receive a transformation that relates the fixture physical reference coordinate system to the physical reference coordinate system of the optical reference, the transformation being determined using the first series of physical references from the fixture and the second series of physical references from the optical reference.

21. The system of claim 19, wherein the control system is further configured to determine or receive a transformation relating the fixture physical reference coordinate system to the second series of physical references.

22. The system of claim 21, wherein the control system is further configured to determine or derive a transformation from the model coordinate system to the second series of physical references.

23. The system of claim 22, wherein the control system is further configured to determine or derive a transformation from the optical reference coordinate system to the model coordinate system.

24. The system of claim 1, wherein the fixture has a series of stands for supporting the glass piece, a first baseline for positioning the glass piece relative to the fixture, and a second baseline for positioning the glass piece relative to the fixture.

25. A method of using a non-contact optical inspection system, comprising: Providing a fixture for supporting the glass sheet, the fixture being provided with an optical reference; imaging the optical reference on the fixture via a camera in an inspection assembly; defining an optical reference coordinate system by analyzing the imaged optical reference via a control system; receiving, via the control system, a mathematical model of the glass sheet in a model coordinate system; as well as The optical reference coordinate system is related to the model coordinate system via at least one transformation via the control system.

26. The method of claim 25, further comprising: The ultraviolet laser of the inspection assembly and the associated optical device form a planar sheet-shaped laser beam and direct the planar sheet-shaped laser beam toward the surface of the glass sheet on the fixture; exciting the surface of the glass sheet at the intersection of the planar sheet-shaped laser beam and the surface of the glass sheet to form visible wavelength lines on the surface of the glass sheet; imaging the visible wavelength line using the camera; determining a first coordinate and a second coordinate in a series of coordinates associated with the visible wavelength line by analyzing imaging data from the camera; determining a third coordinate by triangulation, the third coordinate being associated with each of the first coordinate and the second coordinate in the series of coordinates associated with the visible wavelength line; as well as A three-dimensional map of the surface of the glass sheet is created based on the series of coordinates.

27. The method of claim 26, further comprising: transforming the three-dimensional graph via the at least one transformation to associate the three-dimensional graph with the model coordinate system; calculating an invariant metric using the three-dimensional map in comparison with a mathematical model of the surface in the model coordinate system; as well as The invariant metric is output.

28. The method of claim 27, wherein the at least one transformation is provided as at least one transformation matrix.

Images