JP4698140B2 - System for identifying defects in composite structures - Google Patents

Description

BACKGROUND OF THE INVENTION This invention relates generally to the manufacture of composite structures, and more particularly to systems and methods adapted to find defects during the manufacture of composite structures.

  Composite structures have been known in the art for many years. While the composite structure can be formed in many different ways, one advantageous technique for forming the composite structure is a fiber positioning or automatic verification process. Conventional automatic matching techniques place one or more ribbons of composite material (also known as composite tows) on a substrate. The substrate may be a tool or mandrel, but is typically formed from one or more layers of a composite structure that has been previously aligned and compressed. In this regard, conventional fiber positioning processes use a heat source to assist compression of the composite structure ply at the local nip point. Specifically, the ribbon or tow of the composite material and the underlying substrate are heated at the nip point to improve the tackiness of the ply resin while being securely bonded to the substrate by exposure to compressive forces. . For example, a composite ply can be compressed by a compliant pressure roller as disclosed in US Pat. No. 5,058,497, which is hereby incorporated by reference. To complete this part, additional bands of composite material may be applied in parallel to form a layer and exposed to local heat and pressure during the consolidation process. Another conventional fiber positioning process method is disclosed in US Pat. No. 5,700,337, which is hereby incorporated by reference.

  A composite laminate produced by the fiber positioning process is typically 100% ply-by-ply checked for toe gaps, overlap and twist. The inspection is usually performed manually by the fiber positioner operator or inspector. Until the inspection is complete, the machine must be stopped and the process of arranging the materials must be interrupted. During the inspection, the operator verifies the magnitude of any abnormalities and quantifies the number of abnormalities per given unit area. Abnormalities are repaired as necessary, and the next ply is arranged. However, the manufacturing process is slowed by the inspection process, which is disadvantageous.

  To overcome the disadvantages of manual workpiece inspection, mechanical inspection systems use video and other images that are processed by a computer to detect the presence of irregularities in the object being inspected. To do. For example, U.S. Pat. No. 4,760,444 discloses a machine visual inspection apparatus having a video inspection station for determining reflectivity of various portions of a workpiece. The central processing unit digitizes the reflectance value and stores the digitized value in a storage device. The computer also includes a reference image previously stored in the storage device, which serves as a reference for the reflectance value. Thus, the computer can find anomalies by comparing the reference image with the digitized reflectance values. However, this system provides only one reference point when inspecting a workpiece, which cannot be changed by the operator.

Another inspection system is disclosed in U.S. Pat. No. 4,064,534, which compares the contour of the image of the workpiece electronically with a reference image, and the item being inspected or measured. A television camera and logic circuit that can reject or accept certain items are described. Specifically, the video image of the workpiece is captured by a camera, converted into a digital format, and recorded in a storage device. The recorded image is compared with a reference image previously loaded into the storage device. Based on these image differences, the processor determines whether the work piece passes or fails. However, this system also requires that the reference measurements are preloaded into the computer and cannot subsequently be controlled by the operator.

  Yet another conventional inspection system uses a laser and applies it to the workpiece to identify locations on the workpiece where the reflectivity of the laser changes. For example, gaps or other inconsistencies change the reflectivity of the surface. Changes in reflectivity are interpreted by the computer to identify defects.

However, each of these systems is prone to obtaining false readings due to reflections or other problems caused by ambient illumination or laser-based scanning systems. In particular, these systems cannot accurately identify defects in the contoured / curved areas of the workpiece. In this regard, conventional machine-based inspection systems provide the strong contrast necessary to find defects in all areas of the workpiece, and ambient illumination and material reflectivity interfere with defect identification. Suitable lighting to prevent is missing. The lack of suitable illumination is particularly problematic when inspecting contoured / curved surfaces. This is because the part of the contoured / curved surface that is contoured away from the light source cannot be illuminated properly, so it is impossible to identify the contoured / curved surface defects. is there. This inspection process is further complicated by the appearance of black defects on a black background during the inspection of carbon materials. Furthermore, conventional machine-based inspection systems cannot easily change the definition of a defect or observation area in a controlled manner. Instead, in conventional machine-based inspection systems, the definition of defects is usually predetermined and the size of the observation area is also predetermined, which is undesirable during the inspection process.
US Pat. No. 5,058,497 US Pat. No. 5,700,337 U.S. Pat. No. 4,760,444 U.S. Pat. No. 4,064,534

SUMMARY OF THE INVENTION The system for identifying defects in a composite structure of the present invention can identify defects in all areas of a work piece by better illuminating the surface of the work piece. Defects can also be identified in marked / curved areas. In this regard, the system includes a contoured / curved surface that provides sufficient light and distributes the light over a sufficiently large area of the workpiece to face away from the light. Properly illuminate all of the surface so that it can be fully inspected for defects. In addition, the system of the present invention changes the viewing area in a controlled manner and allows the composite structure to be observed as close as possible so that the system accurately identifies defects in the workpiece. Thus, the present invention saves the time, effort and expense required to otherwise manually inspect areas that cannot be accurately identified.

  One embodiment of a system for identifying defects in a composite structure during manufacture of the composite structure according to the present invention includes a light source, a reflective surface, and a camera. A light source is positioned relative to the composite structure and illuminates the composite structure. The light generated by the light source is reflected from the defects in the composite structure, unlike the non-defect portions of the structure. The light source may be a halogen light. Further, the light source may be movable with respect to the composite structure, and there may be a plurality of light sources at different positions relative to the composite structure to sufficiently illuminate the composite structure. The reflective surface is near the composite structure and is directed towards the illuminated portion of the composite structure. The reflecting surface may be a mirror. In addition, there may be a plurality of reflective surfaces to collaborate and direct the image of the illuminated area of the composite structure to the camera.

  The camera is directed toward the reflective surface and receives a reflected image of the illuminated portion of the composite structure. Thus, the camera may be positioned farther from the illuminated portion of the composite structure than the reflective surface, so that an image of the composite structure can be captured even if the camera cannot be positioned near the composite structure. . The camera may be an infrared sensitive camera or a visible light camera with a filter function that allows infrared light to pass through and may be movable relative to the composite structure. Furthermore, in order to observe the composite structure from the optimum position, there may be a plurality of cameras at different positions with respect to the composite structure.

  Another embodiment of the invention includes the light source and camera described above and a dispersive element. The dispersive element is near the light source and scatters the light generated by the light source across the composite structure and illuminates the composite structure uniformly. The dispersive element may have a stepped shape to scatter light uniformly across the composite structure. The dispersive element may be a parabolic shape with a stepped shape, etc., and may be at least partially curved toward the light source. Further, the dispersive element may be adjustable to direct the scattered light to a predetermined portion of the composite structure from which the camera receives an image.

  Further embodiments of the invention include a light source and a camera as described above, where the light source or camera, or both, are movable relative to the composite structure. Thus, the light source and / or camera can be properly repositioned with respect to different shaped composite structures.

  The composite structure may be made from a plurality of composite bands arranged by an automatic verification process, where the composite band is provided by the head unit and compressed against the underlying composite structure by a compression roll. In this configuration, the reflective surface and the light source are near the compression roll. In some embodiments, the reflective surface and the light source may be attached to the head unit. In embodiments including a dispersive element, the dispersive element and the light source may be attached to the head unit.

  The system of the present invention may also include a marking device for marking the composite structure when a defect is identified. In addition, a processor for processing the image and outputting a response identifying the defect based on the image may be included in the system.

  As a result of the light source and camera configuration, the system of the present invention can observe the composite structure and identify defects within the composite structure, regardless of where the defects are on the workpiece. By using dispersive elements and / or reflective surfaces in the system of the present invention, additional illuminating and observing capabilities are obtained, whereby defects in the workpiece cannot be reached even by conventional systems. It is possible to accurately identify defects in the region.

  Now that the general description of the invention is complete, reference is made to the accompanying drawings. These drawings are not necessarily drawn to scale.

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described more fully with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. However, this invention can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout.

An embodiment of a system for identifying defects in a composite structure according to the present invention is generally indicated by reference numeral 10 in FIGS. As shown in FIG. 1, the system 10 is positioned adjacent to a composite structure 22, which generally includes a plurality of adjacent tows or bands 24 of composite tape. Typically, the band 24 includes a plurality of fibers embedded in a resin or other material that becomes sticky or fluid when heated. According to automatic verification techniques known in the art, the band 24 is placed on a work surface such as a table, mandrel or other tool 26 and compressed using a compression roll 20 to form a composite structure 22. For example, Richard Sharp et al. Published in the “Journal of Thermmoplastic Composite Materials” (January 1995) “Material Selection / Manufacturing Issues for Positioning Thermoplastic Fibers ( The article entitled “Material Selection / Fabrication Issues for Thermal Plastic Fiber Placement” discusses one conventional fiber positioning process, which is incorporated by reference, and was filed on February 6, 2002. “Composite Material Collation Machine and Related Methods for High-speed Collation of Composite Materials (Composite Material Collation
US patent application Ser. No. 10 / 068,735 entitled “Machine and Associated Method for High Rate Collation of Composite Materials” discusses another fiber positioning process, which application is incorporated herein by reference.

  In general, system 10 includes a camera 12 and a light source 14. The camera 12 and the light source 14 produce a visible image that can be captured by the camera 12 with light reflected from a defect-free portion of the composite structure and light that is not reflected from the defect of the composite structure, or vice versa. , Positioned adjacent to the composite structure 22. As will be described in more detail below, the camera 12 is connected to a processor for interpreting the image and / or a storage device for storing the image. For more information on systems and methods for identifying defects in composite structures during manufacturing, see “System and Method for Identifying Defects” filed Mar. 28, 2001. US patent application Ser. No. 09/899922, entitled “in a Composite Structure”, which is incorporated herein by reference.

  As shown in FIG. 1, the camera 12 captures an image of a predetermined portion of the composite structure, typically an image immediately downstream of the nip point where the composite tow joins the underlying structure. Located near the structure 22. Alternatively, as shown in FIG. 2, the reflective surface 16 is an image immediately downstream of the nip point where the composite tow is joined to the underlying structure, ie, an image immediately downstream of the compression roll 20, etc. The reflective surface 16 may be positioned near the composite structure (not shown in FIG. 2) and angled so as to reflect an image of a predetermined portion of the composite structure. In one embodiment of the invention, the angle of the reflective surface 16 relative to the composite structure is 65 °, but the reflective surface 16 may be at an appropriate angle to reflect an image of the illuminated portion of the composite structure to the camera 12. Any angle may be used. The camera 12 may be positioned to face the reflective surface 16 in order to capture images from a short distance of a predetermined portion of the composite structure from the reflective surface 16. In further embodiments of the invention, more than one reflective surface 16 may be used. The reflective surface 16 cooperates to direct an image of the illuminated portion of the composite structure to the camera 12.

  For composite structures with curved / contoured surfaces, it is advantageous if an image of the composite structure is captured from as close as possible to the nip point in order to obtain and process an accurate representation of the composite structure. . Thus, the configuration shown in FIG. 2 is particularly advantageous for capturing an image of the curved / contoured surface of the composite structure. This is because the reflection surface 16 reflects the image of the composite structure from a position as close as possible to the composite structure so that the camera 12 can capture it. In addition, this configuration allows the camera 12 to be placed farther from the composite structure than the reflective surface 16, so that the camera 12 does not interfere with the function of other parts of the fiber locating device and vice versa.

The camera 12 may be a commercially available camera that can take black and white images. For example, in one embodiment, the camera 12 is a television type or other type of video camera having an image sensor (not shown) and a lens 13 through which light passes when the camera is operating. Other types of cameras, such as infrared-sensitive cameras, visible-light cameras with infrared filter function, fiber optic cameras, coaxial cameras, charge-coupled devices (CCD), or complementary metal oxide sensors (CMOS) An image sensor can also be used. The camera 12 may be positioned on a stand (not shown) adjacent to the composite structure 22 or attached to a frame 28 or similar device. In an embodiment that does not include a reflective surface of the present invention, the camera 12 may be positioned about 6 inches from the surface of the composite structure and attached to the frame 28 by a bracket 30 and associated connector 32. However, in embodiments including the reflective surface of the present invention, the reflective surface 16 is positioned approximately 3 inches from the surface of the composite structure 22 and the camera 12 is directed toward the reflective surface 16 as described above, as described above. It may be positioned further away from. In a further embodiment of the invention, the reflective surface 16 is at a different distance from the surface of the composite structure 22, such as from 1 inch to 6 inches, so as to reflect the most accurate image of the surface of the composite structure toward the camera 12. It may be positioned.

  The connector 32 may be a rivet, screw, or the like that attaches the camera 12 to the frame 28 in a stationary position. Alternatively, the connector 32 may be a hinged connector that rotates the camera 12, the light source 14 and the associated assembly away from the composite structure 22. This embodiment is advantageous when other parts of the fiber positioning device, particularly those located behind the camera and associated assembly, must be accessed for maintenance, cleaning, etc. FIG. 2 is an alternative embodiment of a hinged connector 32 that attaches the camera 12, reflective surface 16, light source 14 and associated assembly (ie, camera assembly) to the frame 28 by a bracket 30. The fastener 34 may be a thumbscrew or other fastener that can be removed or loosened relatively easily and can be tightened to secure the camera assembly in an operating position, with the camera assembly being attached to the compression roll 20 and It can be removed or loosened to rotate away from other parts of the fiber positioning device.

  Further, the filter 15 may be positioned on the lens 13 to filter the light in a certain manner. Specifically, according to one embodiment, the filter 15 is designed to filter light so that only the infrared component of light or only certain infrared wavelengths can pass through the camera. Thus, the filter 15 prevents ambient visible light from entering the camera 12 and changing the appearance of the captured image. Other methods of filtering light may be used to achieve the same result. For example, the camera may be designed to include a built-in filter with corresponding optical characteristics. Furthermore, the filter may be positioned between the camera lens 13 and the image sensor. Alternatively, the camera may include an image sensor that senses only in the infrared spectrum (ie, an infrared camera) so that no filtering is necessary.

  The system 10 also includes a unique light source 14 that illuminates the composite structure 22 so that defects 36 on or in the composite structure can be detected by the camera 12. As will be described below, the portion of the composite structure 22 to which the camera 12 or reflective surface 16 of the embodiment of FIG. 2 is directed receives a sufficient amount of illumination from the light source 14, and in some embodiments, the maximum amount. The light source 14 may be positioned relative to the composite structure 22 so as to receive the illumination and highlight the defect 36. Further, the system 10 may include more than one light source. Furthermore, the system 10 may include more than one light source. For example, the embodiment of FIG. 2 includes two light sources positioned relative to the composite structure and a compression roll 20 and camera 12 on either side of the reflective surface 16.

As described above, the light source is adjustably positioned relative to the composite structure by being attached to or attached to the attachment device 27 so that the attachment device 27 can accurately and accurately position the light source as shown in FIG. A main shaft 29, a second shaft 31, and a clamping clamp 33 are included for quick adjustment. The mounting device 27 may be attached to the frame 28, the camera 12, the bracket 30 so that the light source and the camera maintain a certain spatial relationship with each other, or a common for both the light source and the camera. You may attach to the other object which prescribes | regulates a position.

  A common problem in conventional machine observation systems is that they cannot be illuminated effectively, and therefore specific defects such as scratches on a dark background cannot be detected. In particular, the quality and extent of illuminating the surface of the composite structure is greatly influenced by the ambient illumination and the reflectivity of the material. In order to effectively illuminate dark scratches on a dark background, the system of one embodiment of the present invention is advantageous because it uses an infrared light source. In this regard, the light source 14 may be selected from infrared light or another type of light having an infrared component such as incandescent light or halogen light. In this regard, power levels in the range of about 5 W to 25 W in the wavelength range of about 700 nm to 1000 nm are sufficient. In the embodiment shown in FIG. 1, the light source 14 may include light emitting diodes (LEDs), and specifically may include a plurality of LEDs arranged in an array or cluster organization. In one specific embodiment, the light source 14 includes 24 LEDs mounted as an array on a 3 inch square printed circuit board. As a result of infrared illumination, the LED array increases the contrast between the composite structure and the defect 36 over conventional systems. In another embodiment, light source 14 includes an incandescent optical fiber that emits light that is optically sent from a remote source (not shown) to an array of optical fiber sources.

  In the embodiment shown in FIG. 2, the dispersive element 18 is near the light source 14. The dispersive element 18 decomposes and scatters the light emitted from the light source 14 so that the concentrated area of light (ie, hot spots) created by the brightest part of the light source 14 is eliminated. Hot spots are undesirable because they prevent consistent illumination of the composite structure and can cause errors in the processing of images captured by the camera 14. The dispersive element 18 is particularly advantageous for illuminating the curved / contoured surface of the composite structure. This is because a larger portion of the composite structure is illuminated by scattering light. Thus, more light illuminates areas that were not effectively illuminated by conventional systems, such as curved / outlined portions away from the light source 14.

  FIG. 3 is an enlarged view of the light source 14 and the dispersive element 18 according to the embodiment shown in FIG. The light source 14 of this embodiment is composed of four halogen bulbs 38. The dispersive element 18 is advantageously located near the light source 14 and is directed to direct the light emitted by the light source 14 towards the part of the composite structure to which the camera 12 or reflective surface 16 is directed. The dispersive element 18 may be curved toward the light source 14 as in the paraboloid shown in FIG. The dispersive element may have a step 40 on the surface facing the light source 40. The stage 40 may be substantially parallel to the light source 14 and the distance between the steps 40 resolves hot spots that are likely to occur at the dispersive element 18 so that the dispersive element 18 provides consistent illumination of the composite structure. Sufficient to do so, thereby preventing errors in the processing of images captured by the camera 14 caused by inconsistent illumination of the composite structure. Or alternatively, the shape and / or surface configuration of the dispersive element 18 may provide consistent illumination, so long as the light generated by the light source 14 is scattered over the desired portion of the composite structure. It may be changed as follows.

For example, in one embodiment, the dispersive element has a parabolic shape with 17 steps, the width of the step being from 0.125 inches at the outer edge of the element to 0.250 inches at the center of the element. In this range, the step height is uniform 0.116 inches. However, in other embodiments, there may be a different number of steps, the step width may be uniform or variable, and the step height may be uniform or variable. Further, the dispersive element 18 may be tunable to direct light generated by the light source 14 and scattered by the dispersive element 18 to a desired portion of the composite structure. For example, FIG.
The dispersive element 18 may be adjustably attached to the attachment device 27 using fasteners 42 as shown in FIG. The loosened fastener 42 can move within the slot 44 to adjust the angle of the dispersive element 18 relative to the composite structure accordingly. Once the dispersing element is properly positioned, the fasteners 42 can be tightened to secure the dispersing element in the desired position. Adjustment of the dispersive element 18 can also be by other methods known in the art, such as electrical means that allow for remote adjustment of the dispersive element 18.

  It has been found that the composite structure 22 produces a strong return when illuminated across the direction of positioning of the band 24 and that the illumination is substantially reduced when illuminated along the direction of positioning of the band. While conventional systems have attempted to eliminate reversal, at least some systems and methods of embodiments of the present invention have attempted to utilize reversal. In particular, the systems and methods of these examples cast light over the top layer of the composite band in a direction substantially perpendicular to the direction of band positioning to produce a relatively large amount of reflection on the top. Utilizing the high / low-lighting phenomenon by creating in the layer. The underlying layer is much less reflective than the top layer because of its orientation, but if there is a gap or other defect in the top layer, it can be seen and easily found. In addition, top layer twists and other surface defects can change the orientation of the top layer strip and correspondingly alter the reversal of the top layer defect location, i.e., top layer defect location. Reduces the return of light.

  In addition, although high / low-lighting phenomena occur when illuminated with visible or infrared light, the filter 15 used in one embodiment of the system 10 reduces the reflection caused by ambient light. Only the reflection caused by the infrared light source is used to find the defect 36 for substantial removal. Thus, the filter 15 removes ambient light interference when examining the composite structure for defects.

  In any embodiment of the system for identifying defects in the composite structure described herein, one or more light sources 14 (with or without one or more cameras 12 and / or dispersive elements 18). Hereinafter, it may be collectively referred to as a light source). Further, one or more cameras 12 and / or one or more light sources may be movable relative to the composite structure. Multiple cameras 12 and / or multiple light sources and the movability of the camera 12 and / or light sources provide the system 10 with the flexibility to capture the most accurate images of the composite structure. Multiple and / or movable light sources can consistently and fully illuminate the desired portion of the composite structure, regardless of the shape of the composite structure. Similarly, multiple and / or movable cameras 12 can capture an accurate image in any region of the composite structure, regardless of the shape of the composite structure. For this reason, multiple and / or movable light sources and / or cameras are particularly advantageous when illuminating and capturing the curved / outlined portion of the composite structure. Multiple and / or movable light sources and / or cameras are also advantageous for illuminating and capturing a composite band having a width that is difficult to illuminate the entire band and / or difficult to capture the image. Yes, the position of the light source and / or camera may be moved across the band, and / or multiple stationary light sources and / or cameras may be positioned to cover the entire band.

As shown in FIGS. 4 and 5, the system 10 may include any combination of movable and / or stationary cameras and movable or stationary light sources. In further embodiments, the reflective surface 16 may be movable and / or stationary. FIG. 4 shows the movable camera 12 at alternative camera positions 46, 48. This embodiment also shows a stationary light source 50 and a movable light source 52. The movable light source 52 can be moved to an alternative position 54 to sufficiently illuminate the curved and contoured portion of the composite structure 56. FIG. 5 shows an embodiment that includes two movable cameras 12 and two stationary light sources 58 to capture an accurate representation of the fully illuminated and curved surface / shaped surface 60. Alternatively, one or both of the cameras 12 may be stationary and / or one or both of the light sources 58 may be movable. Movement of the camera and / or light source and / or reflective surface may be enabled by means 55 known in the art. For example, electrical or pneumatic servos may be attached to the camera and / or light source to control movement. Examples of electric or pneumatic servos are commercially available from PMA series servo systems available from Pacific Scientific, BMS N-series servo systems available from Baldor Electric Company, and from Compumotor, a division of Parker Hannifin Corporation. There are Neometric and J-Series servo systems.

  Any example system 10 described herein may include a marking device 62 to indicate the location of a defect 36 in the composite structure 22, as shown in FIG. The marking device 62 is an inkjet marking system in one embodiment, which may be mounted on the frame 28 and is activated by the processor 64 or similar device when a defect 36 to be reported to the operator is detected. Specifically, the marking device 62 sprays a color-compatible ink that is easily visible at the location of defects on the surface of the composite structure 22 to create small spots for quick access for repair and treatment. Other marking methods such as audible or visual warnings can also be used.

  The automatic verification process includes the step of guiding the composite band 24 from a material creel (not shown) to an automatic verification or fiber locator, as is known in the art. For example, such machines are manufactured by Cincinnati-Milacron and Ingersoll Milling Machines. Specifically, the composite band 24 is guided to the head unit and supplied under the compression roll 20. Thermal energy concentrated is applied to the incoming material and the underlying material previously aligned to bond the two materials. By a combination of pressure and heat, the composite band 24 is integrated into the previous layer, forming an additional layer of the composite structure 22. Unfortunately, defects 36 can sometimes occur while positioning the composite band 24 on the underlying composite structure 22. For example, in the case of fiber positioning, gaps may be formed between adjacent composite bands or the composite bands may be twisted during positioning.

  According to one embodiment of the invention, when the head unit is moved across the composite structure 22 and the composite band 24 is aligned, the camera 12 and / or reflective surface 16 may be attached to the head unit along with the light source 14 and the dispersive element 18. Well, it captures images of structures and bands in succession. If the composite structure 22 is not flat, the inspection point should be as close as possible to the nip point, as described above. If the composite structure 22 is flat, the inspection point may be further away from the positioning head unit. As will be described in detail below, the image may be stored in storage device 66 for later analysis and / or processed immediately by processor 64.

  FIG. 6 shows an example of an unprocessed camera image 68 that includes a range of pixels from black to white via a plurality of halftones. Specifically, unprocessed camera image 68 shows the contrast between a potential defect, such as a gap between composite bands 24, and the rest of the composite structure without defects. As shown in FIG. 6, the potential defect is shown as a black or gray area 70 and the remaining portion of the composite structure 22 remains substantially white 72. However, potential defects need to be further processed to determine whether they are acceptable or unacceptable, as described below. Furthermore, only a predetermined area of the camera image is inspected to minimize interference.

The processor 64 receives the image 68 from the camera 12 or from the storage device 66 where the image is initially stored. The processor 64 and storage device 66 may be components of a conventional computer such as an IBM style PC or Apple-based MAC. The processor 64 manipulates the image to facilitate reliable defect detection.

  FIG. 7 shows an image 74 of the camera, which is the same image shown in FIG. 6 after binarization by the processor 64. Specifically, all halftones above a certain threshold are changed to white, and all halftones below the threshold are changed to black, increasing the contrast of the defect 36 and improving detection accuracy. To do. Advantageously, the system also includes a user interface 76 that communicates with the processor 64. A user interface 76 such as a touch screen display driven by the processor 64 provides user controls 78 for adjusting the binarization threshold. Generally, the setting of the threshold value for binarization involves a trade-off between the accuracy of detecting a defect and the resolution for displaying the defect. However, normally, the binarization threshold is set to about 150 in the range of 0 to 255. The interface 76 may provide other controls as will be described later.

  FIG. 8 illustrates one embodiment of a portion of user interface 76 according to system 10 of the present invention. The user interface 76 operates from many software applications such as Windows® 98, Windows® / NT, Windows® 2000, Windows® CE, Linux, Unix® and the like. be able to. The user interface 76 also includes a display screen 80, such as on a computer monitor, and the operator moves the cursor over the display screen 80 to allow binarization thresholds, inspection areas, and detected defects 36 ± 0. A keyboard and mouse (not shown) may be included so that an acceptable tolerance of the maximum width of allowed defects, such as 0.03 inches, can be entered. Display screen 80 may be touch sensitive so that an operator can enter desired settings by manually pressing an area of the display screen. As shown in FIG. 8, the composite structure 22 image may be an unprocessed camera image 68 or a binarized camera image 74, but displayed for viewing by an operator. In addition to the displayed image of the composite structure 22, the display screen 80 includes a table of defects 82 that lists the defects 36 found and provides information about each defect such as location, size, and the like. The display screen 80 may also include a status indicator 84 that displays whether a particular image area is acceptable based on a predetermined criterion such as the tolerances described above.

  FIG. 9 shows another portion of the user interface 76 by the system 10 of the present invention when the two cameras 12 are capturing an image of the composite structure as described above. In this embodiment of the user interface 76, a display screen 86 similar to the display screen 80 is included. As shown in FIG. 9, the image of the composite structure 22 can be an unprocessed camera image 68 or a binarized camera image 74, which is displayed for viewing by the operator, Indicated by images 88 and 90. In addition to the displayed image of the composite structure 22, the display screen 86 also includes a table of defects 82, which lists the defects 36 found for each camera image and provides information about each defect such as location, size, etc. . The display screen 86 also includes a status display 84 that displays whether the image area is acceptable based on a predetermined criterion such as the tolerances described above. Alternatively, in order to display the images of the two cameras 12, the two user interfaces shown in FIG. 8 are used with links, and each interface displays an image from one camera, and the other camera. A link to a user interface that displays an image from may be presented. Further, in order to display the images of the plurality of cameras 12, a plurality of user interfaces shown in FIG. 8 and / or FIG. 9 are used with links to display images from one or more cameras, You may make it show the link to the user interface which displays the image from these cameras.

Accordingly, the present invention provides a composite structure by providing a light source 14 having an infrared component so that defects that are often undetectable by conventional systems, such as dark defects on a dark background or bright defects on a light background, can be identified. An improved system 10 for identifying defects 36 in 22 is provided. In particular, an advantageous embodiment of the improved system 10 for identifying defects 36 in the composite structure is most accurate in any region of the composite structure, whether curved or contoured. Reflective surface 16, dispersive element 18, and multiple and / or movable light sources and / or cameras are provided to ensure that images are captured and processed. As a result, the system 10 of the present invention allows an operator to quickly identify and correct defects 36 that would otherwise cause structural flaws or inconsistencies that could affect the integrity of the composite structure 22. This reduces wasted material, reduces the labor spent on inspection, and reduces machine downtime during the manufacturing process. Therefore, on average, the cost of the composite structure is reduced.

  Many variations and other embodiments will occur to those skilled in the art to which the invention pertains having the benefit of the teachings presented in the foregoing description and the associated drawings. Therefore, it should be understood that the invention is not limited to the specific embodiments disclosed, and that variations and other embodiments are intended to be included within the scope of the claims. Although specific terms are used herein, they are used in a general and descriptive sense and not for purposes of limitation.

1 is a schematic diagram of a system for identifying defects in a composite structure during manufacture according to one embodiment of the invention. FIG. FIG. 4 is a diagram of an alternative embodiment of a system for identifying defects in a composite structure during manufacture according to the present invention. FIG. 3 is a detailed view of a light source according to one embodiment of a system for identifying defects in the composite structure shown in FIG. FIG. 2 is a diagram of an alternative embodiment of a system for identifying defects in a composite structure according to the present invention including a movable camera and a stationary light source and a movable light source. FIG. 6 is a diagram of an alternative embodiment of a system for identifying defects in a composite structure according to the present invention that includes two movable cameras and a stationary light source. 4 is a graph of computer readings for identifying defects in a composite structure according to one embodiment of the present invention. It is a graph of the binarized image of the graph of FIG. FIG. 4 is a diagram of a computer display device and selected user controls according to one embodiment of the present invention. FIG. 6 is a diagram of a computer display device and selected user controls according to an alternative embodiment of the present invention including two camera images.

Explanation of symbols

10 systems, 12 cameras, 14 light sources, 16 reflective surfaces, 18 dispersive elements, 22 composite structures.

Claims (39)

A system for identifying defects in a composite structure during manufacturing,
A light source positioned relative to the composite structure to illuminate the composite structure, wherein light generated by the light source is reflected differently from a defect-free portion of the composite structure due to defects in the composite structure; The system further includes:
A dispersive element adjacent to the light source for scattering light generated by the light source across the composite structure, comprising a reflective surface having a stepped structure to more uniformly scatter light across the composite structure Distributed elements,
A reflective surface adjacent to the composite structure and directed toward an illuminated portion of the composite structure;
Wherein after the image from the reflecting surface is reflected, I saw including a camera directed towards said reflecting surface to receive the image of the illuminated portion of the composite structure,
The composite structure includes a plurality of composite bands, and projects the light over the top layer of the composite band in a direction substantially perpendicular to the direction of band positioning to provide a relatively large amount of reflection on the top layer. A system for identifying defects in composite structures that, by generating, takes advantage of high repetition and low repetition . The system for identifying defects in a composite structure according to claim 1, wherein the camera is positioned farther from an illuminated portion of the composite structure than the reflective surface. The system for identifying defects in a composite structure according to claim 1, wherein the reflective surface is a mirror. The system for identifying defects in a composite structure according to claim 1, wherein the reflective surface includes a plurality of reflective surfaces that cooperate to direct the image to the camera. The system for identifying defects in a composite structure according to claim 1, wherein the camera is an infrared sensitive camera. The system for identifying defects in a composite structure according to claim 1, wherein the camera is a visible light camera having a filter function to pass infrared rays. The system for identifying defects in a composite structure according to claim 1, wherein the light source is halogen light. The system for identifying defects in a composite structure according to claim 1, wherein the camera is movable relative to the composite structure. The system for identifying defects in a composite structure according to claim 1, wherein the camera includes a plurality of cameras in different portions of the composite structure. The system for identifying defects in a composite structure according to claim 1, wherein the light source is movable relative to the composite structure. The system for identifying defects in a composite structure according to claim 1, wherein the light source includes a plurality of light sources at different positions relative to the composite structure. The system for identifying defects in a composite structure according to claim 1, further comprising a marking device for indicating defects on the composite structure. The system for identifying defects in a composite structure according to claim 1, further comprising a processor for processing the image and outputting a response identifying a defect based on the image. Before SL composite strip, the composite strip is aligned by the automatic matching process to be compressed to a composite structure underlying the offered and compression rolls by the head unit, the reflecting surface and the light source is adjacent to said compression rolls, The system for identifying defects in a composite structure according to claim 1. The system for identifying defects in a composite structure according to claim 14, wherein the reflective surface and the light source are attached to the head unit. A system for identifying defects in a composite structure during manufacturing,
A light source positioned relative to the composite structure to illuminate the composite structure, and the light generated by the light source is reflected by a defect in the composite structure, unlike a defect-free portion of the composite structure; The system further includes:
A dispersive element adjacent to the light source for scattering light generated by the light source across the composite structure, comprising a reflective surface having a stepped structure to more uniformly scatter light across the composite structure Distributed elements,
Look including a camera for receiving images of the illuminated portion of the composite structure,
The composite structure includes a plurality of composite bands, and projects the light over the top layer of the composite band in a direction substantially perpendicular to the direction of band positioning to provide a relatively large amount of reflection on the top layer. A system for identifying defects in composite structures that, by generating, takes advantage of high repetition and low repetition . A system for identifying defects in a composite structure during manufacturing,
A light source positioned relative to the composite structure to illuminate the composite structure, and the light generated by the light source is reflected by a defect in the composite structure, unlike a defect-free portion of the composite structure; The system further includes:
A dispersive element adjacent to the light source for scattering light generated by the light source across the composite structure, having a parabolic shape deformed around the light source, making the light more uniform across the composite structure A dispersive element having a stepped structure that is parabolic to scatter into
Look including a camera for receiving images of the illuminated portion of the composite structure,
The composite structure includes a plurality of composite bands, and projects the light over the top layer of the composite band in a direction substantially perpendicular to the direction of band positioning to provide a relatively large amount of reflection on the top layer. A system for identifying defects in composite structures that, by generating, takes advantage of high repetition and low repetition . 18. A system for identifying defects in a composite structure for identifying defects in the composite structure according to claim 16 or 17, wherein the dispersive element is at least partially curved toward the light source. 17. The dispersive element is adjustable with respect to a composite structure such that the dispersive element scatters light over a predetermined portion of the composite structure from which the camera receives an image. Or a system for identifying defects in a composite structure according to claim 17; The system for identifying defects in a composite structure according to claim 16 or 17, wherein the camera is an infrared sensitive camera. 18. The system for identifying defects in a composite structure according to claim 16 or 17, wherein the camera is a visible light camera with a filter function that allows infrared light to pass through. The system for identifying defects in a composite structure according to claim 16 or 17, wherein the light source is halogen light. 18. A system for identifying defects in a composite structure according to claim 16 or 17, wherein the camera is movable relative to the composite structure. 18. A system for identifying defects in a composite structure according to claim 16 or 17, wherein the camera comprises a plurality of cameras at different positions relative to the composite structure. The system for identifying defects in a composite structure according to claim 16 or 17, wherein the light source is movable relative to the composite structure. 18. A system for identifying defects in a composite structure according to claim 16 or 17, wherein the light source comprises a plurality of light sources at different positions relative to the composite structure. 18. A system for identifying defects in a composite structure according to claim 16 or 17, further comprising a marking device for indicating defects on the composite structure. 18. A system for identifying defects in a composite structure according to claim 16 or 17, further comprising a processor for processing the image and outputting a response for identifying defects based on the image. Before SL composite strip, the composite strip is aligned by the automatic matching process to be compressed to a composite structure underlying the offered and compression rolls by the head unit, the camera and the light source is adjacent to said compression rolls, wherein Item 18. A system for identifying a defect in a composite structure according to Item 16 or 17. 30. The system for identifying defects in a composite structure according to claim 29, wherein the camera, the light source and the dispersive element are attached to the head unit. A system for identifying defects in a composite structure during manufacturing,
A light source positioned relative to the composite structure to illuminate the composite structure, wherein light generated by the light source is reflected by a defect in the composite structure, unlike a defect-free portion of the composite structure; The system further includes:
A camera for receiving an image of the illuminated portion of the composite structure;
A dispersive element adjacent to the light source for scattering light generated by the light source across the composite structure, the dispersive element having a stepped structure to more uniformly scatter light across the composite structure; only including,
The composite structure includes a plurality of composite bands, and projects the light over the top layer of the composite band in a direction substantially perpendicular to the direction of band positioning to provide a relatively large amount of reflection on the top layer. A system for identifying defects in composite structures that, by generating, takes advantage of high repetition and low repetition . 32. The system for identifying defects in a composite structure according to claim 31, wherein the camera is an infrared sensitive camera. 32. The system for identifying defects in a composite structure according to claim 31, wherein the camera is a visible light camera with a filter function to pass infrared light. 32. The system for identifying defects in a composite structure according to claim 31, wherein the light source is halogen light. 32. The system for identifying defects in a composite structure according to claim 31, wherein the camera includes a plurality of cameras at different positions relative to the composite structure. 32. The system for identifying defects in a composite structure according to claim 31, wherein the light source includes a plurality of light sources at different positions relative to the composite structure. 32. The system for identifying defects in a composite structure according to claim 31, further comprising a marking device for indicating defects on the composite structure. 32. The system for identifying defects in a composite structure according to claim 31, further comprising a processor for processing the image and outputting a response identifying defects based on the image. Before SL composite strip, the composite strip is aligned by the automatic matching process to be compressed to a composite structure underlying the offered and compression rolls by the head unit, the camera and the light source is adjacent to said compression rolls, wherein 32. A system for identifying a defect in a composite structure according to item 31.

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