Systems and methods for detecting defect on surface and abrading surface

Abstract

A defect detection system includes a light source configured to project a fringe pattern onto a surface. The fringe pattern includes a ratio of dark portions to light portions of at least 1.5 and a fringe pattern having a period of at least 1 millimeter. The defect detection system further includes an image capturing device configured to capture an image of the projected fringe pattern. The defect detection system further includes a movement mechanism configured to move the image capturing device at an angle of between 30° and 90°, measured from perpendicular to the surface. The defect detection system further includes an image analyzer configured to detect a defect on the surface, based on the captured image. The defect detection system further includes a defect characterizer configured to provide a defect characteristic. The defect detection system further includes a communication component configured to report the defect characteristic.

Description

PA102947W002SYSTEMS AND METHODS FOR DETECTING DEFECT ON SURFACE AND ABRADING SURFACETechnical Field

[0001] The present disclosure relates to systems and methods for detecting a defect on a surface. The present disclosure further relates to a robotic abrading system. The present disclosure further relates to a method of abrading a semi-diffuse surface.Background

[0002] The automotive industry often needs to prepare surfaces of vehicle parts or replacement parts (e.g., a bumper) for various purposes (e.g., painting), or to repair surfaces of vehicle parts or replacement parts due to defects incurred during painting or coating. Typical surface preparation and repair processes include, for example, physical surface modification of vehicle surfaces such as sanding and polishing. Surface preparation and repair of defects on surfaces can utilize different tools, and materials.

[0003] Manufactured objects are typically visually inspected by personnel in order to detect flaws, imperfections, or other unwanted features on their respective surfaces. Visual inspects by personnel are costly (e.g., requiring personnel to be paid to visually inspect the produced objects), may result in worker fatigue from repeated manual inspection and repair, and are less reliable since the detection rate is based upon the various dissimilar visual abilities and the application of subjective measures by the inspectors.

[0004] To address these issues, electronic systems have been implemented which utilize cameras, lights, and computers to capture images objects and perform analysis using the images to detect defects including unwanted surface features. However, conventional electronic systems may not be suitable for detecting defects on diffuse or semi -diffuse surfaces, which reflect light in a more scattered manner than specular surfaces.

[0005] Therefore, there remains a need for improved defect detection on diffuse, semidiffuse, or reflective surfaces. Furthermore, techniques are desired for automating this process as well as other paint applications (e.g., primer sanding, clear coat defect removal, clear coat polishing, etc.) amenable to the use of abrasives and / or robotic inspection and repair on diffuse or semi-diffuse surfaces.Summary

[0006] In a first aspect, a method of detecting a defect on a surface is provided. The method includes positioning an imaging system proximate the surface. The imaging system includes a light source having a fringe pattern. The fringe pattern has a ratio of dark portions to lightportions of at least 1.5. The imaging system further includes a camera positioned at an angle with respect to the surface. The angle is between 30° and 90°, measured from perpendicular to the surface. The method further includes capturing images of the surface, using the imaging system. The method further includes analyzing the images, and based on the analysis, detecting the defect on the surface. The method further includes outputting a defect characteristic for the detected defect.

[0007] In a second aspect, a robotic abrading system is provided. The robotic abrading system includes an imaging system. The imaging system is configured to project, using a light source, a fringe pattern onto a surface. The fringe pattern has a ratio of at least 1.5 dark to light portions. The imaging system is further configured to capture, using an image capturing device, an image of the displayed fringe pattern on the surface. An image capturing device positioning mechanism positions the image capturing device at an angle with respect to the surface. The angle is between 30° and 90°, measured from perpendicular to the surface. The imaging system is further configured to analyze, using an image analyzer, the captured image and detect a defect on the surface. The imaging system is further configured to determine a defect characteristic for the detected defect based on the analysis. The robotic abrading system further includes an abrading system. The abrading system is configured to move, using a tool movement system, an abrasive tool proximate a location of the detected defect. The abrading system is further configured to move, using an abrasive movement mechanism, the abrasive tool across the surface, over the location of the detected defect. The abrading system is further configured to apply a force to the abrasive tool, using a force compliance tool.

[0008] In a third aspect, a method of abrading a semi-diffuse surface is provided. The method includes imaging the semi-diffuse surface. Imaging the semi-diffuse surface includes positioning a first image capturing device proximate the semi-diffuse surface. Imaging the semidiffuse surface further includes projecting a fringe pattern onto the semi-diffuse surface. The fringe pattern includes a ratio of dark portions to light portions of at least 1.5. Imaging the semidiffuse surface further includes imaging the projected fringe pattern. The method further includes detecting, based on the imaged fringe pattern, a defect at a defect location on the semidiffuse surface. The method further includes abrading the semi-diffuse surface, with an abrading tool, at the defect location. The method further includes imaging the semi-diffuse surface after the abrading operation. The method further includes evaluating the abrading operation.

[0009] In a fourth aspect, a defect detection system is provided. The defect detection system includes a light source configured to project a fringe pattern onto a surface. The fringe pattern includes a ratio of dark portions to light portions of at least 1.5 and a fringe pattern having a period of at least 1 mm. The defect detection system further includes an image capturing deviceconfigured to capture an image of the projected fringe pattern. The defect detection system further includes a movement mechanism configured to move the image capturing device into a position. The position includes the image capturing device at an angle with respect to the surface. The angle is between 30° and 90°, measured from perpendicular to the surface. The defect detection system further includes an image analyzer configured to, based on the captured image, detect a defect on the surface. The defect detection system further includes a defect characterizer configured to characterize at least one of a location of the defect on the surface, a depth of the defect with respect to the surface, a type of the defect, or a size of the defect. The defect detection system further includes a communication component configured to report the defect characteristic.

[0010] The details of one or more examples of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims.Brief Description of the Drawings

[0011] Exemplary embodiments disclosed herein may be more completely understood in consideration of the following detailed description in connection with the following figures. The figures are not necessarily drawn to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number.

[0012] FIG. 1 illustrates a schematic block diagram of a robotic abrading system, according to embodiments of the present disclosure;

[0013] FIG. 2 illustrates a schematic block diagram of a defect detection system, according to embodiments of the present disclosure;

[0014] FIG. 3 A illustrates a schematic diagram of an example fringe pattern, according to embodiments of the present disclosure;

[0015] FIGS. 3B-3E are photographs showing example defects on surfaces captured according to embodiments of the present disclosure;

[0016] FIG. 4 illustrates a schematic diagram showing an assembly line with a painted vehicle, a defect detection system, and a robotic abrading system that may benefit from embodiments herein;

[0017] FIG. 5 illustrates a schematic diagram of a system that may benefit from embodiments herein;

[0018] FIG. 6 illustrates a schematic diagram of an example robotic paint inspection and repair system that may benefit from embodiments herein;

[0019] FIG. 7 illustrates a flowchart of a method of detecting a defect on a surface, according to embodiments of the present disclosure;

[0020] FIG. 8 illustrates a flowchart of a method of abrading a semi-diffuse surface, according to embodiments of the present disclosure;

[0021] FIG. 9 illustrates a system architecture for embodiments herein;

[0022] FIG. 10 illustrates an example of a mobile device that can be used in the embodiments shown in previous Figures; and

[0023] FIG. 11 illustrates an example computing device that can be used in embodiments shown in previous Figures.Detailed Description

[0024] In the following description, reference is made to the accompanying figures that form a part thereof and in which various embodiments are shown by way of illustration. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense.

[0025] In the following disclosure, the following definitions are adopted.

[0026] As used herein, all numbers should be considered modified by the term “about.” As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably.

[0027] As used herein as a modifier to a property or attribute, the term “generally,” unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within + / - 20 % for quantifiable properties).

[0028] The term “substantially,” unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 10% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0029] The term “about,” unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 5% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0030] As used herein, the terms “first” and “second” are used as identifiers. Therefore, such terms should not be construed as limiting of this disclosure. The terms “first” and “second” when used in conjunction with a feature or an element can be interchanged throughout the embodiments of this disclosure.

[0031] As used herein, “at least one of A and B” should be understood to mean “only A, only B, or both A and B.”

[0032] As used herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range as well as the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0033] As used herein, the term “diffuse surface” refers to a surface that scatters light in many directions rather than reflecting the light in just one direction. Diffuse surfaces typically have a matte or non-glossy finish.

[0034] As used herein, the term “semi-diffuse surface” refers to a semi-matte surface or a semi-gloss surface, that exhibits characteristics of both diffuse and specular reflection. Semidiffuse surfaces often have a soft sheen or subtle gloss. Semi-diffuse surfaces can appear smoother than fully diffuse surfaces, but still lack sharp reflections of a fully specular surfaces.

[0035] As used herein, the term “reflective surface” refers to any surface that has reflective properties. A reflective surface may exhibit characteristics of specular reflection. Some examples of reflective surfaces include metallic surfaces, vehicle body / surfaces, painted metal, etc.

[0036] As used herein, the term “F stop” refers to a ratio of a focal length of a camera lens to a diameter of an aperture.

[0037] As used herein, the term “vehicle” is not limited to a car, and includes an automobile, a truck, a boat, an airplane, helicopter, bus, or other means of transportation.

[0038] As used herein, the term “surface” is not limited to a specular surface but can include matte, metal, or other type of surface finishes. The term “surface” need not be a painted surface in all cases.

[0039] As used herein, the term “defect” refers to an unwanted feature such a blemish or unwanted surface condition. Defects can include, but are not limited to, a hair or other fiber, an air bubble, a crater, dust or other particulate within / upon a painted surface, an area missing coating such as a scratch, dent or other type of depression upon a painted surface, and a projection, bump or raised portion of a painted surface, and / or an area of undesirable color such as a different color, in which the paint has not been properly applied or properly cured. Some examples of defects include micropops - tiny sub millimeter sized areas where solvent pop breaks through clear coat; orange peel - uneven layers of paint; mars - areas where vehicle was touched; shallow paint, and the like.

[0040] As used herein, the term “surface modification” and variations thereof refer to repair of a surface, abrading, scuffing, sanding, polishing, buffing, and the like.

[0041] As used herein, the terms “board,” “processor,” “processing assembly,” and “server” (as well as other utilized descriptive names) may be used interchangeably, and these terms are meant to generally refer to some sort of processor-based entity without limiting the referred to entity to any particular hardware or software configuration.

[0042] As used herein, the term “fluid” means any one or combination of a pure fluid, a fluid in combination with particulate such as a slurry, debris from surface modification, or any of the like.

[0043] As used herein, the term “reasonable exposure” refers to an exposure value that provides a contrast between a light portion and the dark portion of a fringe pattern, such that the light portion and the dark portion are distinguishable. A reasonable exposure may avoid saturation of any pixel (i.e., a pixel that hits “Full White” value of 255) of an image capturing device.

[0044] As used herein, the term “excessive exposure” refers to an exposure value that fails to provide a contrast between the light portion and the dark portion of a fringe pattern, such that the light portion and the dark portion are indistinguishable. The excessive exposure may cause saturation of one or more pixels (i.e., a pixel that hits “Full White” value of 255) of the image capturing device 114.

[0045] As used herein, the term “reasonable resolution” refers to a resolution value that provides enough pixels for a minimum defect size. For example, an image capturing device may provide at least 10 pixels width for a smallest defect size, or at least 40 pixels width for a normal defect size. As an example, an image capturing device may provide 0.025 millimeter or 25 microns (pm) wide pixels for a 1 mm defect size.

[0046] Referring now to the Figures, FIG. 1 illustrates a block diagram of an example robotic abrading system 100, according to embodiments of the present disclosure.

[0047] The robotic abrading system 100 includes an imaging system 110. The imaging system 110 is configured to project, using a light source 112, a fringe pattern 111 onto a surface 113. The fringe pattern 111 may include a plurality of alternating dark and light portions. The fringe pattern 111 has a ratio of at least 1.5 dark to light portions. The width of each dark portion may be greater than or equal to 1.5 times the width of each light portion. In some embodiments, the ratio of dark portions to light portions may be at least 1.8, at least 2.0, at least 2.5, or at least 3.0. The fringe pattern 111 may have a greater ratio of dark portion to light portion (i.e., greater than 1.5) than a conventional fringe pattern (e.g., 1).

[0048] The imaging system 110 is further configured to capture, using an image capturing device 114, an image of the displayed fringe pattern 111 on the surface 113. The imagecapturing device 114 may include a camera or a video camera. In some embodiments, the image capturing device 114 may include a varifocal lens.

[0049] An image capturing device positioning mechanism 116 positions the image capturing device 114 at an angle with respect to the surface 113. The angle is between 30° and 90°, measured from perpendicular to the surface 113. In other words, the image capturing device 114 may be positioned at an angle of between 30° and 90° relative to a normal to the surface 113. Hereinafter, any angle described with respect to the surface 113 is considered to be measured from the perpendicular or relative to the normal to the surface 113.

[0050] The surface 113 (which may be a diffuse or semi-diffuse surface in some examples) may reflect the fringe pattern 111 more specularly at angles between 30° and 90° with respect to the surface 113 than at angles less than 30° with respect to the surface 113. Furthermore, at angles between 30° and 90° with respect to the surface 113, undesired illumination of the dark portions of the fringe pattern 111 may reduce. Therefore, the image capturing device 114 being positioned at an angle of between 30° and 90° with respect to the surface 113 may facilitate capturing images of the displayed fringe pattern 111.

[0051] In some embodiments, the image capturing device 114 may be positioned at an angle of between 45° and 90° with respect to the surface 113. In some embodiments, the image capturing device 114 may be positioned at an angle of between 60° and 90° with respect to the surface 113. In some embodiments, the image capturing device 114 may be positioned at an angle of between 75° and 90° with respect to the surface 113.

[0052] The imaging system 110 is further configured to analyze, using an image analyzer 118, the captured image and detect a defect on the surface 113. Defects on the surface 113 may cause interruptions in the fringe pattern 111 reflected by the surface 113. Such interruptions may be detected in the images of the fringe pattern 111 to detect the defects. Specifically, in some embodiments, analyzing may include detecting an interruption in the fringe pattern 111 in the captured images. The image analyzer 118 may be configured to detect interruptions in the fringe pattern 111 in the captured images to detect defects on the surface 113.

[0053] The imaging system 110 is further configured to determine a defect characteristic for the detected defect based on the analysis. The defect characteristic may include a detected location of the defect on the surface 113, a detected size of the defect, a detected type of the defect, or a detected depth of the defect with respect to the surface 113. The detected type of defect may include, for example, scratches, presence of undesired or foreign material, craters, etc. In some embodiments, the surface 113 may be a multilayered surface. The detected depth of the defect may include an indication of a layer of the multilayered surface including thedefect. For example, the imaging system 110 may characterize that the detected defect is present in a basecoat layer of a multilayered paint surface.

[0054] The imaging system 110 may provide improved detection of the defect on the surface 113. Specifically, the fringe pattern 111 having a ratio of at least 1.5 dark to light portions may reduce resolution demands for the image capturing device 114, without requiring excessive exposure (excessive exposure requirements may limit defect characterization). This may facilitate distinguishing between the dark and light portions of the fringe pattern 111 with suitable properties (e.g., resolution, aperture, and exposure) of the image capturing device 114, thereby improving defect detection. For example, as compared to a conventional fringe pattern, the fringe pattern 111 may allow the image capturing device 114 to have a wider aperture, a reasonable exposure, and a reasonable resolution, especially if the fringe patterns have a small fringe period (e.g., less than 10 millimeters fringe period).

[0055] Moreover, the imaging system 110 may be suitable for detecting defects on diffuse or semi-diffuse surfaces. The image capturing device 114 being positioned at an angle of between 30° and 90° with respect to a normal to a diffuse surface may improve detection of small or micro defects on the diffuse surface. The image capturing device 114, when positioned at an angle of between 30° and 90° with respect to the normal to the surface 113, may capture improved image(s) of the projected fringe pattern 111, even in the case of the surface 113 being diffuse or semi-diffuse. The fringe pattern 111 and the positioning of the image capturing device 114 may together enable detecting defects on diffuse or semi-diffuse surfaces. For example, the imaging system 110 may detect defects on a partially diffuse or primarily diffuse primer coat.

[0056] In some embodiments, the fringe pattern 111 may include a fringe period of at least 1 millimeter (mm), at least 2 mm, at least 3 mm, at least 4 mm, or at least 5 mm. In some embodiments, the fringe pattern 111 may include a fringe period of less than 10 mm or less than 8 mm. As the fringe period decreases, a number of dark and light portions of the fringe pattern 111 per unit length may increase. Having a fringe period of the fringe pattern 111 that is greater than 1 mm and less than 10 mm may provide a suitable number of dark and light portions per defect, thereby improving defect detection.

[0057] The image capturing device 114 may be selected or configured to further reduce detection of diffuse reflections from the surface 113. In some embodiments, the image capturing device 114 may include an F stop of at least 8, at least 10, at least 15, or at least 20. In some embodiments, the image capturing device 114 may include an F stop of less than 25. An F stop of at least 8 may limit the range of emission angles received by the image capturing device 114 for each pixel, which may reduce detection of light from ambient environment or distantportions of the surface 113. In conjunction with the fringe pattern 111 and the aforementioned angle of the image capturing device 114 with respect to the surface 113, this may further improve accuracy and precision of detecting defects.

[0058] In some embodiments, the imaging system 110 may be further configured to characterize the surface 113 proximate the detected defect. The surface characteristic may include a curvature of the surface 113 proximate the detected defect. The surface characteristic may further include a specularity or glossiness of the surface 113. In some examples, the imaging system 110 may be configured to adjust the fringe pattern 111 and / or the angle of the image capturing device 114 with respect to the surface 113 based on the surface characteristic.

[0059] The robotic abrading system 100 further includes an abrading system 120. The abrading system 120 is configured to move, using a tool movement system 105, an abrasive tool 122 proximate a location of the detected defect. The abrasive tool 122 may be any tool (e.g., abrasive disc, abrasive pad, etc.) that is capable of abrading the surface 113. In some embodiments, the abrasive tool 122 may be a sanding tool.

[0060] The abrading system 120 is further configured to move, using an abrasive movement mechanism 124, the abrasive tool 122 across the surface 113 over the location of the detected defect. The abrasive tool 122 may be moved across the surface 113 over the location of the detected defect in any suitable manner, as per desired application attributes. In some embodiments, the abrasive movement mechanism 124 may be configured to move the abrasive tool 122 in a linear, rotary, orbital, or random orbital movement pattern.

[0061] The abrading system 120 is further configured to apply a force to the abrasive tool 122, using a force compliance tool 126. The application of the force to the abrasive tool 122, along with the movement of the abrasive tool 122 across the surface 113, may cause the abrasive tool 122 to abrade a portion of the surface 113 at the location of the detected defect.

[0062] The abrading system 120 may function in cooperation with the imaging system 110 to repair the detected defect on the surface 113. The imaging system 110 may detect the defect, and the abrading system 120 may repair the detected defect. The robotic abrading system 100 may be capable of performing paint or clearcoat repair process manually or automatically. The robotic abrading system 100 may be particularly useful for identifying basecoat or clearcoat defects and performing a basecoat or clearcoat repair process.

[0063] In some embodiments, a motive robotic arm 102 may include the imaging system 110 and the abrading system 120. The motive robotic arm 102 including both the imaging system 110 and the abrading system 120 may detect defects on the surface 113 as well as perform repair operations (or abrading operations) on locations of the detected defects on the surface 113. In such embodiments, the robotic abrading system 100 may further include a modechanging mechanism 130. The mode changing mechanism 130 may change the motive robotic arm 102 from an imaging mode, where the image capturing device 114 is proximate the surface 113, to an abrading mode, where the abrasive tool 122 is proximate the surface 113. In some embodiments, the mode changing mechanism 130 may rotate an end of arm configuration of the motive robotic arm 102. The rotation of the end of arm configuration of the motive robotic arm 102 may change the motive robotic arm 102 from the imaging mode to the abrading mode.

[0064] As discussed above, the abrading system 120 is configured to move, using the tool movement system 105, the abrasive tool 122 proximate the location of the detected defect and move, using the abrasive movement mechanism 124, the abrasive tool 122 across the surface 113, over the location of the detected defect. In some embodiments, the tool movement system 105 may include the motive robotic arm 102. Furthermore, the motive robotic arm 102 may include an end-effector 108 including the abrasive movement mechanism 124.

[0065] In some other embodiments, a first motive robotic arm may include the imaging system 110 and a second motive robotic arm may include the abrading system 120. In such embodiments, the first motive robotic arm may detect defects on the surface 113 and the second motive robotic arm may perform repair operations (or abrading operations) on locations of the detected defects on the surface 113.

[0066] The robotic abrading system 100 may further include an abrasive strategy generator 140 configured to, based on the defect characteristic, generate an abrasive strategy for the abrasive tool 122. The abrasive strategy may include, for example, an angle of the abrasive tool 122 when contacting the surface 113, an applied pressure to the abrasive tool 122, and a speed of movement of the abrasive tool 122.

[0067] The abrasive strategy may be communicated to a controller of a defect repair system, for example, included as part of the robotic abrading system 100. Specifically, a control signal may be generated and transmitted to the defect repair system. The control signal may include the abrasive strategy. In some embodiments, the abrasive strategy may be automatically implemented by the robotic abrading system 100.

[0068] In some embodiments, the imaging system 110 may be further configured to do a post-abrasive operation image analysis of the location of the detected defect. In other words, the imaging system 110 may be configured to evaluate the abrading operation carried out by the abrading system 120. The post-abrasive operation image analysis of the location of the detected defect may be performed to evaluate whether the detected defect was sufficiently repaired by the abrading system 120.

[0069] FIG. 2 illustrates a block diagram of an example defect detection system 200, according to embodiments of the present disclosure.

[0070] The defect detection system 200 includes a light source 202 configured to project a fringe pattern 203 onto a surface 201. The fringe pattern 203 may include a plurality of alternating dark and light portions.

[0071] The fringe pattern 203 includes a ratio of dark portions to light portions of at least 1.5. The width of each dark portion may be greater than or equal to 1.5 times the width of each light portion. In some embodiments, the ratio of dark portions to light portions may be at least 1.8, at least 2.0, or at least 2.5. In some embodiments, the ratio of dark portions to light portions may be at least 3. The fringe pattern 203 may have a greater ratio of dark portion to light portion (i.e., greater than 1.5) than a conventional fringe pattern (e.g., 1).

[0072] Furthermore, the fringe pattern 203 of at least some embodiments herein has a fringe period of at least 1 mm. In some embodiments, the fringe pattern 203 may include a fringe period of at least 2 mm, at least 3 mm, at least 4 mm, or at least 5 mm. In some embodiments, the fringe pattern 203 may include a fringe period of less than 10 mm or less than 8 mm.

[0073] The defect detection system 200 further includes an image capturing device 204 configured to capture an image of the projected fringe pattern 203. In some embodiments, the image capturing device 204 may include a camera or a video camera. In some embodiments, the image capturing device 204 may include a varifocal lens. In various embodiments herein, a phase-offset technique may be implemented as while capturing an image of a projected fringe pattern. The phase-offset technique may include mechanically actuating the light source that projects the fringe pattern.

[0074] The defect detection system 200 further includes a movement mechanism 210 configured to move the image capturing device 204 into a position. The position includes the image capturing device 204 at an angle with respect to the surface 201. The angle is between 30° and 90°, measured from perpendicular to the surface 201. Hereinafter, any angle described with respect to the surface 201 is considered to be measured from the perpendicular or relative to the normal to the surface 201.

[0075] The surface 201 (which may be a diffuse or semi-diffuse surface in some examples) may reflect the fringe pattern 203 more specularly at angles between 30° and 90° with respect to the surface 201 than at angles less than 30° with respect to the surface 201. Furthermore, at angles between 30° and 90° with respect to the surface 201, undesired illumination of the dark portions of the fringe pattern 203 may reduce. Therefore, the image capturing device 204 being positioned at an angle of between 30° and 90° with respect to the surface 201 may facilitate capturing images of the displayed fringe pattern 203.

[0076] In some embodiments, the image capturing device 204 may be positioned at an angle of between 45° and 90° with respect to the surface 201. In some embodiments, the imagecapturing device 204 may be positioned at an angle of between 60° and 90° with respect to the surface 201. In some embodiments, the image capturing device 204 may be positioned at an angle of between 75° and 90° with respect to the surface 201.

[0077] The defect detection system 200 further includes an image analyzer 206 configured to detect a defect on the surface 201, based on the captured image. Specifically, the image analyzer 206 may analyze the image(s) captured by the image capturing device 204 to detect the defect on the surface 201. Defects on the surface 201 may cause interruptions in the fringe pattern 203 reflected by the surface 201. Such interruptions may be detected in the images of the fringe pattern 203 to detect the defects. Specifically, in some embodiments, analyzing may include detecting an interruption in the fringe pattern 203 in the captured images. The image analyzer 206 may be configured to detect interruptions in the fringe pattern 203 in the captured images to detect defects on the surface 201.

[0078] The defect detection system 200 further includes a defect characterizer 212 configured to characterize at least one of a location of the defect on the surface 201, a depth of the defect with respect to the surface 201, a type of the defect, and / or a size of the defect. The detected type of defect may include, for example, scratches, presence of undesired or foreign material, craters, etc. In some embodiments, the surface 201 may be a multilayered surface. The detected depth of the defect may include an indication of a layer of the multilayered surface including the defect. For example, the defect characterizer 212 may characterize that the detected defect is present in a basecoat layer of a multilayered paint surface.

[0079] The defect detection system 200 may provide improved detection of the defect on the surface 201. Specifically, the fringe pattern 203 including a ratio of dark portions to light portions of at least 1.5 may reduce resolution demands for the image capturing device 204, without requiring excessive exposure (excessive exposure requirements may limit defect characterization). This may facilitate distinguishing between the dark and light portions of the fringe pattern 203 with suitable properties (e.g., resolution, aperture, and exposure) of the image capturing device 204, thereby improving defect detection. For example, as compared to a conventional fringe pattern, the fringe pattern 203 may allow the image capturing device 204 to have a wider aperture, a reasonable exposure, and a reasonable resolution, especially if the fringe patterns have a small fringe period (e.g., less than 10 millimeters fringe period). As the fringe period decreases, a number of dark and light portions of the fringe pattern 203 per unit length may increase. The fringe period of the fringe pattern 203 being greater than 1 mm and less than 10 mm may provide a suitable number of dark and light portions per defect, thereby improving defect detection.

[0080] Moreover, the defect detection system 200 may be suitable for detecting defects on diffuse or semi-diffuse surfaces. The image capturing device 204 being positioned at an angle of between 30° and 90° with respect to a normal to a diffuse surface may improve detection of small or micro defects on the diffuse surface. The image capturing device 204, when positioned at an angle of between 30° and 90° with respect to the normal to the surface 201, may capture improved image(s) of the projected fringe pattern 203, even in the case of the surface 201 being diffuse or semi-diffuse. The fringe pattern 203 and the positioning of the image capturing device 204 may together enable detecting defects on diffuse or semi-diffuse surfaces. For example, the defect detection system 200 may detect defects on a partially diffuse or primarily diffuse primer coat.

[0081] The image capturing device 204 may be selected or configured to further reduce detection of diffuse reflections from the surface 201. In some embodiments, the image capturing device 204 may include an F stop of at least 8, at least 10, at least 15, or at least 20. In some embodiments, the image capturing device 204 may include an F stop of less than 25. An F stop of at least 8 may limit the range of emission angles received by the image capturing device 204 for each pixel, which may reduce detection of light from ambient environment or distant portions of the surface 201. In conjunction with the fringe pattern 203 and the aforementioned angle of the image capturing device 204 with respect to the surface 201, this may further improve accuracy and precision of detecting defects.

[0082] The defect detection system 200 may further include a surface characterizer 214 configured to characterize the surface 201 proximate the detected defect. The surface characteristic may include a curvature of the surface 201 proximate the detected defect. The surface characteristic may further include a specularity or glossiness of the surface 201. In some examples, the defect detection system 200 may be configured to adjust the fringe pattern 203 and / or the angle of the image capturing device 204 with respect to the surface 201 based on the surface characteristic.

[0083] The defect detection system 200 further includes a communication component 216 configured to report the defect characteristic. In some embodiments, the communication component 216 may be configured to communicate the surface characteristic. In some embodiments, the communication component 216 may communicate a control signal to a controller of an abrading system (such as the robotic abrading system 100). The control signal may include an abrasive strategy based on the defect characteristic and / or the surface characteristic. One or more parameters (e.g., angle, applied pressure, or speed) implemented by the abrading system may be modified based on the abrasive strategy.

[0084] In some embodiments, the defect detection system 200 may further include a motive robot arm 208. The movement mechanism 210 may include the motive robot arm 208. The motive robot arm 208 may position the image capturing device 204 at an angle of between 30° and 90°, measured from perpendicular to the surface 201.

[0085] FIG. 3A illustrates a schematic diagram of an example fringe pattern 300 according to embodiments of the present disclosure. The fringe pattern 300 is shown as being reflected off a surface on which the fringe pattern 300 is projected onto.

[0086] As shown in FIG. 3A, the fringe pattern 300 may include a plurality of dark portions 304 (shown with hatching) and a plurality of light portions 302 alternating with the plurality of dark portions 304. Each dark portion 304 may have a dark width 304W, and each light portion 302 may have a light width 302W.

[0087] The fringe pattern 300 may include a ratio of dark to light portions. The ratio of dark to light portions may be defined as a ratio of the dark width 304W to the light width 302W. The fringe pattern 300 may further include a fringe period 306. The fringe period 306 may be defined as the combination of one light portion 302 and one dark portion 304. The fringe period 306 may be equal to the sum of widths of adjacent light and dark portions 302, 304.

[0088] The fringe pattern 300 may be projected onto a surface, and images thereof may be analyzed for defects. As the fringe period 306 decreases, the potential to detect smaller defects may increase. The increase in defect detection potential may be attributed to the presence of additional dark and light portions in the fringe pattern 300 as the fringe period 306 decreases. However, as the fringe period 306 decreases, the difficulty to distinguish between the light portions 302 and the dark portions 304 for an image capturing device, such as a camera, may also increase. This increase in difficulty may be attributed to an increase in resolution and / or exposure requirements to distinguish between the dark and light portions of the fringe pattern 300.

[0089] Embodiments of the present disclosure may mitigate the aforementioned difficulty by increasing the ratio of dark to light portions of the fringe pattern 300. In various embodiments of the present disclosure, the ratio of dark portions to light portions may be at least 1.5. In other words, the dark width 304W may be greater than or equal to 1.5 times the light width 302W. To further improve the images captured by the image capturing device, embodiments of the present disclosure may position the image capturing device at a more “glancing angle,” that is, at an angle greater than about 30 degrees measured with respect to a normal to the surface, where the surface reflects more specularly than at angles less than about 30 degrees with respect to the normal to the surface.

[0090] Embodiments of the present disclosure may employ an image capturing device having an F stop of at least 8. An F stop of at least 8 may limit the range of emission angles received by the image capturing device for each pixel, which may reduce detection of light from ambient environment or distant portions of the surface. In conjunction with the fringe pattern and the aforementioned angle of the image capturing device with respect to the surface, this may further improve accuracy and precision of detecting defects.

[0091] Embodiments herein may enable capturing improved images of the fringe pattern 300 projected onto the surface using the image capturing device, such that the captured images may be analyzed to detect even small defects on the surface. Embodiments herein may also enable detecting small defects on a diffuse or semi-diffuse surface, such as basecoat, powder primer, etc.

[0092] FIGS. 3B-3E are photographs showing exemplary defects on diffuse surfaces (specifically, a basecoat). The photographs are captured by a defect detection system (e.g., the imaging system 110 of FIG. 1 or the defect detection system 200 of FIG. 2), according to embodiments of the present disclosure.

[0093] In FIG. 3B, defects 352 are visible in a fringe pattern 350 and characterized as field of base-pockets in the basecoat. In FIG. 3C, defects 362 are visible in a fringe pattern 360 and characterized as line impressions / base scratches in the basecoat. In FIG. 3D, a defect 372 is visible in a fringe pattern 370 and characterized as a fiber in the basecoat. In FIG. 3E, a defect 382 is visible in a fringe pattern 380 and characterized as a complex crater in the basecoat.

[0094] FIG. 4 illustrates a schematic diagram showing an assembly line with a painted vehicle, a defect scanning system, and robotic repair apparatus, that may benefit from the embodiments of the present disclosure. Embodiments of the present disclosure may be implemented in the assembly line and various components thereof.

[0095] FIG. 4 is a schematic illustrating an assembly line system 400 with a painted vehicle 402, a carriage 404, a rail system 406, a defect identification system 408, and a robotic repair apparatus 410. The robotic repair apparatus 410 can have a base 412, an arm 414, an end effector 416 and an assembly 418. As shown in FIG. 4, the assembly 418 can include a first tool 420, a second tool 422, one or more cameras 424 and a light 426. However, while FIG. 4 illustrates one example scenario in which systems described herein may be useful, it is expressly contemplated that embodiments herein may be useful in a wide variety of systems.

[0096] FIG. 4 illustrates the painted vehicle 402 mounted to the carriage 404 in a known manner. The carriage 404 can be coupled to the rail system 406 to transport the painted vehicle along the assembly line system 400 as shown by arrow A. Although a vehicle body or chassis is shown in FIG. 4, it is recognized with the present disclosure, the systems, processes, techniques,and apparatus can be utilized with any object (e.g., bumpers, hub caps) and is not limited to the automotive field. Furthermore, although FIG. 4 depicts the assembly line system 400 as a continuous process, it is understood that the systems, processes, techniques and apparatus can be utilized with a non-continuous process such as where a portion of assembly is performed in one location, fabrication is then halted and the vehicle 402 is then moved to another location (such as another facility) and other portions of the assembly are performed at the other location. The rail system 406 is purely exemplary and can include various types of transportation mechanisms.The rail system need not be continuously moveable but can be a stop station, diversion station or other type configuration as known in the art. The carriage 404 may not be coupled to the rail system 406 in some embodiments. Additionally, while FIG. 4 illustrates a system where a vehicle 402 is moved within the system, it is expressly contemplated that, in some embodiments, vehicle 402 remains stationary and abrading and / or imaging systems move with respect to the vehicle instead.

[0097] After baking to cure the paint, the painted vehicle 402 (sometime referred to as a chassis, a body or simply an object herein) mounted to the carriage 404 can enter the defect identification system 408. The defect identification system 408 can perform a global scan of all visible external facing surfaces of the painted vehicle 402 that may have defects according to some examples. However, a partial scan on only some surfaces may be performed according to further examples. The defect identification system 408 can be constructed and operate in one or more of the manners described in U.S. Patent Application Ser. No. 15 / 932,865, which was filed on May 9, 2018, and U.S. Patent Application Ser. No. 16 / 866,110, which was filed on May 4, 2020, the entire disclosures of each of which are incorporated herein by reference, or using another suitable imaging system.

[0098] The painted vehicle 402 can pass from the defect identification system 408 along the rail system 406 to a defect repair location 428 (sometimes also called a defect repair area or a second location herein). Robotic repair of the defect(s) on the painted vehicle 402 can be performed at the defect repair location 428 by the robotic repair apparatus 410, which is located within the defect repair location 428.

[0099] The base 412 can be coupled to the arm 414 of the robotic repair apparatus 410. As shown in FIG. 4, the robotic arm 414 can be capable of movement in any of six dimensions relative to the base 412, with the capability to perform translations or rotations about an x-axis, y-axis, and / or z-axis. The robotic repair apparatus 410 can have a force control unit (discussed subsequently) and the end effector 416 with the assembly 418 mounted thereto.

[0100] The first tool 420 and the second tool 422 can be configured to selectively interact with a surface such as a surface of the painted vehicle 402. The first tool 420 can be a backuppad configured to hold an abrasive for sanding, grinding and the like, in one embodiment, or another suitable abrasive tool. During an abrasive operation, the first tool 420 via an abrasive disc 430, or other suitable abrasive article, can abrade a surface of the painted vehicle 402 to remove material. The first tool 420 can be attached to the assembly 418 using adhesive, hook and loop, clip system, vacuum, or other suitable attachment system. Similarly, the second tool 422 can be a second abrasive tool such as an abrasive pad 432 configured for polishing or buffing the surface of the painted vehicle 402. However, according to further examples the second tool 422 can have other configurations as known in the art such as a wiping medium, finer grain sanding implement, and / or fluid removal tool (vacuum, air knife, etc.), etc. The second tool 422 can be attached to the assembly 418 using adhesive, hook and loop, clip system, vacuum or other suitable attachment system.

[0101] The assembly 418 can be configured such that that the first tool 420 and the second tool 422 share substantially parallel (and indeed substantially aligned) actuation axes Al and Bl, respectively. Put another way, the first tool 420 can have a first axis Al about which the first tool 420 is configured to rotate to perform surface modification of the workpiece. The second tool 422 can have a second axis Bl about which the second tool 422 is configured to rotate. The first axis Al and the second axis Bl can be substantially aligned along the z-axis direction in the coordinate framework shown in FIG. 4. However, the first tool 420 can be on an opposing side of the assembly 418 from the second tool 422. The first tool 420 and the second tool 422 can be any of or combination of linear, rotary, orbital or random orbital devices.

[0102] During the paint or clearcoat repair process, fluid may be dispensed on the workpiece prior to, during, or subsequent to the utilization of either of the first tool 420 or the second tool 422. This process fluid may combine with particulate matter from the process to create a slurry. The particulate matter composing this slurry is generally caused by the sanding process, which usually takes place prior to a polishing or buffing step (using the second tool 422, for example). One or more wiping tools or implements (not shown) may be employed to remove the slurry and / or excess liquid as desired.

[0103] The one or more cameras 424 can be mounted to the assembly 418 adjacent the first tool 420 and the second tool 422. The one or more cameras 424 can have an axis Cl (passing through center of the lens(es)) that can be arranged substantially perpendicular to the first axis Al and second axis Bl. However, one or more mirrors can be employed such that the one or more cameras 424 can be arranged in any manner desired relative to the first tool 420 and the second tool 422. It can be desirable to mount the one or more cameras 424 on the assembly 418 close to a center of gravity of the assembly 418 as this can reduce likelihood of obstruction and / or unwanted vibration of the one or more cameras 424. The assembly 418 can be pivoted asdesired to bring one of the first tool 420, the second tool 422, or the one or more cameras 424 into an interfacing relationship with the surface of the painted vehicle 402. In embodiments herein, the one or more cameras 424 can be positioned by the robotic repair apparatus 410 as desired to scan the surface of the painted vehicle 402 in a desired area as further discussed. The one or more cameras 424 can include a high resolution (e.g., greater than 12MP) digital camera, for example. The one or more cameras 424 can have a zoom lens, according to some examples. However, a zoom lens is not required in all examples as the robotic repair apparatus 410 can move the position of the one or more cameras 424 as desired according to some examples. Thus, the robotic repair apparatus 410 can move the one or more cameras 424 toward or away from the surface of the painted vehicle 402 as desired. According to one example, the one or more cameras 424 can be configured to focus on an area about 150 mm by 150 mm at approximately 1 m distance. However, other area sizes and distances are contemplated and the area and distance provided above are provided for exemplary purposes. With defects for the painted vehicle 402 typically being smaller than 1 mm2 various criteria such as resolution, zoom capability, distance, area, etc. can be manipulated as desired to achieve desired outcome of identifying the presence of the defect(s) on the surface of the painted vehicle 402 using the one or more cameras 424.

[0104] The light 426 can be mounted to the assembly 418 adjacent the one or more cameras 424. The light 426 can be a generic white light according to some examples. However, characteristics of the light 426 such as size, color, position relative to the one or more cameras 424, etc. can be modified as desired as discussed in U.S. Patent Application Ser. Nos. 15 / 932,865 and 16 / 866,110.

[0105] The arrangement of the one or more cameras 424 and the light 426 is purely exemplary in FIG. 4. Other arrangements and positioning relative to the first tool 420 and / or the second tool 422 are also contemplated. For example, it is also contemplated that the one or more cameras 424 and / or the light 426 can be mounted to a gantry system or other feature that is coupled to the robotic repair apparatus 410. Thus, the assembly 418 and / or the end effector 416 could be bypassed and need not be coupled to carry the one or more cameras 424 and / or the light 426 in some arrangements. In such arrangements, the gantry system or other feature may still be manipulated to move with movement of the arm 414, however.

[0106] Via mounting to the assembly 418, the end effector 416, the force control unit (discussed subsequently) and the arm 414, the first tool 420 and the second tool 422, and the one or more cameras 424 have the ability to be positioned within the provided degrees of freedom by the robotic repair apparatus 410 (6 degrees of freedom in most cases) and any other degrees of freedom (e.g., a compliant force control unit) with its reference frame. This arrangement canallow for positioning of the first tool 420 and the second tool 422, and the one or more cameras 424 as desired to perform repair and imaging. The one or more cameras 424 and the light 426 can also be manipulated to be swept over the surface of the painted vehicle 402 to gather images from multiple positions as known in defect identification systems such as U.S. Patent Application Ser. Nos. 15 / 932,865 and 16 / 866,110.

[0107] FIG. 5 shows a schematic diagram of a system 500 that may benefit from embodiments herein. The system 500 includes a controller 502, the defect identification system 408 and the robotic repair apparatus 410 according to one example. The controller 502 can electronically communicate with the defect identification system 408 and the robotic repair apparatus 410. While FIG. 4 and FIG. 5 are discussed together herein, it is expressly contemplated that FIG. 5 may be implemented in a number of other suitable arrangements.

[0108] The defect identification system 408 can be configured to detect the presence of one or more defects upon the surface of an object such as the painted vehicle 402 (FIG. 4) as previously discussed. As shown in FIG. 5, the defect identification system 408 can include a first plurality of lights 504 which are placed along the pathway or direction in which the carrier of FIG. 4 (and the conveyor of FIG. 4) transports the produced object.

[0109] Each of the first plurality of lights 504 can each configured to respectively become selectively activated or energized and to thereafter selectively and controllably emit light energy. In one non-limiting example, each of the first plurality of lights 504 comprise a light emitting diode type light, although other types of lights may be utilized. The first plurality of lights 504 can be distributed about the conveyor or movement assembly effective to produce a substantially uniform amount of light about and upon the object as the object moves along the path or direction. The first plurality of lights 504 can be arranged to produce a substantially uniform amount of intensity along this path or direction and on and about the object as it is moving.

[0110] The defect identification system 408 can further include a plurality of inspection cameras 506 which are also placed along the pathway or direction in which the carrier transports the object. The plurality of inspection cameras 506 can be to cooperatively receive reflected light energy being reflected from the surface of the object. Each of the plurality of inspection cameras 506 can be selectively energized and selectively activated once energized.

[0111] The reflected light energy gathered by the plurality of inspection cameras 506 includes first data or image data (image information) about the characteristics (e.g., visual characteristics) of the surface. This first data can be used to detect defects upon the surface of the object and for the other purposes discussed herein including in directing the one or more cameras 506 to scan particular portions of the surface of the object. The defect identification system 408 with the plurality of inspection cameras 506 and the lights 504 can be arranged tocapture first data regarding substantially an entirety of the visible surfaces of the object (the exterior surfaces of the vehicle, for example).

[0112] The defect identification system 408 can have a dedicated processing assembly 508, which may comprise several distinct computer processors acting under stored program control, or a single computer processor assembly. According to further examples, the processing assembly 508 could be a component of the controller 502.

[0113] The processing assembly 508 can have numerous features or components not specifically shown. These can include an image tracking server or processor, post processing server or processor, a “NAS” or archive server or processor, a trigger board, and an encoder, for example. The processing assembly can further include a simulator 510.

[0114] The encoder can be communicatively coupled to the tracking server. In a nonlimiting embodiment, the encoder can include a commercially available friction wheel encoder, which is manufactured and sold by Edon Controls, Inc. of Troy, Michigan. Other types of positional encoders may be utilized. The encoder can be movably coupled upon and to the conveyor or movement assembly and frictionally engages the carrier and turns (e.g., rotates) as the carrier moves along the conveyor or movement assembly. Such turning can provide continual information to the processing assembly 508 concerning the location of the carrier, and hence, the object along the path or direction. The simulator 510 can include a commercially available MATLAB® simulator with Simulink Math Works® tools. The simulator 510 can be a separate and distinct processing system from the processing assembly 508. The simulator 510 can be communicatively coupled to computer systems and monitors remote from the processing assembly 508 in some examples. Thus, the simulator 510 can be communicatively coupled to the controller 502 in a direct manner in some examples.

[0115] Tracking can also be achieved using a camera-based vision tracking system and / or can be accomplished using 3D cameras rather than the encoder. In the case of a camera-based vision system, there is a vision tracking server sending position data to the trigger board.

[0116] The processing assembly 508 can be electronically coupled to an output monitor and / or display assembly 512. The output monitor and / or display assembly 512 can include or be part of a display computer portion, operating under stored program control. The output monitor and / or display assembly 512 can include multiple display computer portions. The processing assembly 508 can be electronically coupled to each of the first plurality of cameras 506, one or more tracking cameras 514, and one or more high speed cameras 516.

[0117] The image processing server or processor can be communicatively coupled to the image capture server or processor. The post processing server or processor can be communicatively coupled to the image processing server or processor. The post processingserver or processor can be communicatively coupled to the “NAS” or archive server or processor. The trigger board, image server, image processing server, post processing server, NAS, display computer portion, and tracking server can each connected to a communications network (such as, by way of example and without limitation, an Ethernet® network) through a switch and hence are in selective communication with each other through the network. The first plurality of lights 504 may also connected to the network. The plurality of cameras 506 and the plurality of lights 504 are each respectively and selectively “energizable” or “activatable” upon the receipt of commands from the triggering board or server.

[0118] Services such as windows service (e.g., stand-alone program) are also contemplated. Example services are: PLC service - communicate with PLC to get plant data about vehicle; tracking service - communicate with trigger board and other services to coordinate scanning process; image capture service - acquires images from the camera, image processing or GPU service - performs image processing steps to find defect regions of interest in the captured frames; classification service - neural network classifies the regions found; cluster service - locates found regions on 3D surface and clusters multiple images of same defect together on the surface, sizes defect, makes final determination about defect type, then creates images and data about the found defect. The services also include a reporting service and an overhead display service (for displaying images on the output monitor). The services are distributed on the servers in various configurations.

[0119] The trigger board can be loaded with a table to map the vehicle positions where the cameras and lights will be triggered during a scan. The trigger board can input vehicle position from the encoder (or vision tracking system) and then triggers the cameras and lights at the specified locations. The trigger board can also have inputs from / to photo-eyes that are used to resynchronize to predefined tracking synchronization locations when the vehicle breaks the photoeye. The trigger board can utilize positional information from the encoder to determine the identity and sequence of lights from the first plurality of lights 504 to illuminate and the identity and sequence of the first plurality of cameras 506 to activate. In essence, raw image is captured of and along the surface of the object as it is moved along the direction or path. The raw captured image data can be communicated to the processing assembly 508 (such as to an image capture server). The raw capture image data can then be communicated to other components such as the image processing server, the controller 502, etc. for analyzation.

[0120] It is also contemplated that the controller 502 and / or the processing assembly 508 (such as via the image processing server and / or post processing server) can perform a selected sequence of image processing algorithms which are cooperatively effective to create first data (sometimes called first scan data herein) that comprises information such as a processed imageof each of the raw captured image data (from raw images received). The processed images (first data or first scan data) can contain one or more regions of interest on the surface or can comprise a global entirety of the visible surfaces. The first data can additionally include information relating to one or more defects. Analysis can be performed in order to ascertain the identity (one or more characteristics) and position of respective ones of the one or more defects upon the surface. The first data can then be communicated to the controller 502, a storage medium (e.g. NAS server) and utilized as further discussed herein. Display of the first data (and indeed the scan data discussed subsequently) can occur in “real time” (e.g. sufficiently quickly that a user does not notice a delay), near “real time” (within a delay of less than about 4 seconds) or can be retrieved for review from the storage medium.

[0121] The defect identification system 408 can also include the one or more tracking cameras 514 which can be coupled to the tracking server (component of the processing assembly 508). These one or more tracking cameras 514 (and / or the one or more high speed cameras 516) can cooperatively provide positional information to the tracking server about the location or position of the object to be inspected as that object moves due to the movement of the conveyor or movement assembly. The one or more tracking cameras 514 and / or high-speed cameras 516 can supplement or replace the encoder. The one or more tracking cameras 514 and / or the highspeed cameras 516 can be coupled to the triggering board and the processing assembly 408 (such as the tracking server). The one or more tracking cameras 514 can collect object positional information along the path or direction to the triggering board and such information may be used in solely or in combination with the positional information from the encoder. The one or more high speed cameras 516 can gather “stereo information” such as vibration information using at least two cameras. The one or more high speed cameras 516 can be used to determine the orientation of the object within the carrier and such orientation information as desired. While the defect identification system 408 can be highly effective in identifying defects or potential defects, the defect identification system 408 can be a complex system with many components. The defect identification system 408 is not typically suitable for use in the vicinity of the robotic repair apparatus 410 due to the possibility of obstruction, vibration, or other interference, and also because a significant amount of space may be required for the robotic repair apparatus 410. As discussed previously in FIG. 4, typical practice is for the vehicle (the object) to be transported to a location separate from the defect identification system 408 for the robotic repair apparatus 410 to be performed. Moreover, in some configurations, a single defect identification system 408 may be used to supply defect information for use in more than one downstream robotic repair apparatus 410.

[0122] The robotic repair apparatus 410 as previously discussed can be used for sanding and polishing one or more defects on a surface in accordance with examples herein. The robotic repair apparatus 410 can have the one or more cameras 424 (previously discussed), which may be used to locate paint / clearcoat / mat or other defects to be repaired. The robotic repair apparatus 410 includes a moving mechanism 552, which may be used to move an end-of-arm assembly 418 (FIG. 4) into proximity of a defect repair area. The robotic repair apparatus 410 can include one or more sensor(s) 554 such as a force sensor or other sensor(s) and / or actuator(s) described herein. The robotic repair apparatus 410 can include a dedicated controller, which controls movement and sensing of the arm 414 and related components. However, it is expressly contemplated that, in some embodiments, the arm 414 and / or the components mounted thereon can have their own controllers or can be controlled by controller 502. The dedicated controller can receive and execute movement and sensing commands such as from controller 502.

[0123] The end-of-arm assembly 418 has been previously discussed and can include a variety of tools, as illustrated in previous FIG. 4, for example. However, it is expressly contemplated, as illustrated in FIG. 5, that, in other embodiments, some components may be located elsewhere (not on the assembly 418) but rather coupled to the arm 414.

[0124] The first tool 420 can be mounted on the arm 414. The first tool 420, in some embodiments, is coupled to a first end effector 556. In some examples, the second tool 422 can be mounted to the arm 414. The second tool 422, if used, may be coupled to a second end effector 558. A fluid removal tool 560 may be mounted to the arm 414. However, it is expressly contemplated that, in some examples, some of these components may not be one or may be on a separate arm from the arm 414. For example, the arm 414 could support the first tool 420, e.g., a sanding tool, and a second arm could support the one or more cameras 424, the second tool 422 and / or other components.

[0125] In one example, the arm 414 is moved into place by an arm movement mechanism 562. The first tool 420 and the second tool 422, the one or more cameras 424 and the fluid removal tool 560 may also be moved into place by the arm movement mechanism 562, in one embodiment, or may each have their own movement mechanism that moves them into position on or adjacent the surface. The robotic repair apparatus 410 can have a force control unit 564. This force control unit 564 may also be located on the arm 414 to control interactions between the arm 414, an end effector system, and a workpiece surface.

[0126] In some examples, an airline 566 and a fluid dispenser 568 can feed from the arm 414 to the assembly 418 (FIG. 4) to provide necessary air and fluid supply as may be necessary for operating the first tool 420 and / or the second tool 422. The fluid removal tool 560 can also becoupled to the force control unit 564. The fluid removal tool 560 may be, for example, a fabricbased wiping medium, an air knife, a vacuum system, or another suitable tool. However, it is also contemplated that, in some embodiments, the fluid removal tool 560 and be coupled to a separate force control unit than that used for the first tool 420 and the second tool 422. It is also contemplated that, in other embodiments, the fluid removal tool 560 could be a passive tool with no associated force control unit. In some examples, the fluid removal tool 560 may be moved through space using a mechanism that will control variables such as the pitch, tilt, and yaw of an active wiping motion of the fluid removal tool 560.

[0127] The force control unit 564 may maintain proper force or pressure between the first tool 420, the second tool 422, and / or the fluid removal tool 560 and the surface of the object. The fluid removal tool 560 may function in conjunction with a fluid removal mechanism 572, in some examples. The fluid removal mechanism 572 may be a pad, vacuum, brush, or scraping tool used to remove particulate matter, debris, liquid, or slurry from the wiping medium of the fluid removal tool 560. The fluid removal mechanism 572 may help to provide a suitably absorbent and effective wiping medium for cleaning the workpiece surface more than once.

[0128] The controller 502 can be in electronic communication with the camera (the one or more cameras 424) and the robotic paint repair apparatus 410. The controller 502 can be configured to control the one or more cameras 424 to scan an area of the surface (a portion of the entire exposed surface) based upon the first data (discussed above determined and provided by the defect identification system 408). The scan of the area by the one or more cameras 424 can collect and provide scan data representing a location and / or other information relating to one or more defects on the surface of the object at the repair location. In contrast, the first data represents information gathered by the defect identification system 408 at a location that differs from the repair location where the robotic repair apparatus 410 operates and the one or more cameras 424 are located. The controller 502 is configured to manipulate the robotic arm (the arm 614) to position the tool (either the first tool 420 or the second tool 422) based upon at least the scan data gathered by the one or more cameras 424 at the repair location.

[0129] The controller 502 can be a digital controller, having one or more processors, can be software implemented, or can be implemented by a combination of software and hardware. The controller 502 can have various functions and capability such as those of the processing assembly 508 described previously. Various other functions are contemplated including as an interface between the defect identification system 408 and the robotic repair apparatus 410. The controller 502 can have various functions. These functions can be implemented in hardware, software, firmware, or any combination thereof, located locally or remotely. If implemented in software, the functions can be stored on or transmitted over a computer-readable medium as oneor more instructions or code and executed by a hardware-based processing unit. The computer- readable media can include computer-readable storage media, which corresponds to a tangible medium such as data storage media, or communication media including any medium that facilitates transfer of a computer program from one place to another, e.g., according to a communication protocol. In this manner, the computer-readable media generally can correspond to tangible computer-readable storage media which is non-transitory, or a communication medium such as a signal or carrier wave. The data storage media can be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code, and / or data structures for implementation of the techniques described in this disclosure. A computer program product can include a computer-readable medium.

[0130] By way of example, and not limitation, such computer-readable storage media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer - readable medium. For example, if instructions are transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium.

[0131] It should be understood, however, that the computer-readable storage media and the data storage media do not include connections, carrier waves, signals, or other transitory media, but are instead directed to non-transitory, tangible storage media. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0132] Instructions can be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other equivalent integrated or discrete logic circuitry, as well as any combination of such components. Accordingly, the term “processor,” as used herein can refer to any of the foregoing structures or any other structure suitable for implementation of the techniques described herein. In addition, in some aspects, the functionality described herein can be provided within dedicated hardware and / or softwaremodules. Also, the techniques could be fully implemented in one or more circuits or logic elements.

[0133] The techniques of this disclosure can be implemented in a wide variety of devices or apparatuses, including a wireless communication device or wireless handset, a microprocessor, an integrated circuit (IC) or a set of ICs (e.g., a chip set). Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, various units can be combined in a hardware unit or provided by a collection of interoperative hardware units, including one or more processors as described above, in conjunction with suitable software and / or firmware.

[0134] The functions, techniques or algorithms described herein may be implemented in software in one example. The software may consist of computer executable instructions stored on the computer readable media or the computer readable storage device such as one or more non-transitory memories or other type of hardware-based storage devices, either local or networked. Further, such functions correspond to modules, which may be software, hardware, firmware, or any combination thereof. Multiple functions may be performed in one or more modules as desired, and the examples described are merely examples. The software may be executed on a digital signal processor, ASIC, microprocessor, or other type of processor operating on a computer system, such as a personal computer, server, or other computer system, turning such computer system into a specifically programmed machine.

[0135] FIG. 6 illustrates a schematic diagram of a robotic paint inspection and repair system 600 that may benefit from embodiments herein. The robotic paint inspection and repair system 600 can include a robotic repair unit 602 including a robotic arm 604 and a robotic inspection unit 606 (a second robot) including a robotic arm 608. The systems may be controlled by a motion controller, which may receive instructions from one or more application controllers 610. The application controller 610 may receive input, or provide output, to a user interface 612 in addition to or alternative to other controllers.

[0136] The robotic repair unit 602 includes a force control unit 614 and an end effector 616 that can be aligned with an assembly 618. The assembly 618 may include a first tool 620, a second tool 622, one or more cameras 624, and a light. The robotic inspection unit 606 can include various components including one or more cameras 624 mounted on the robotic arm 608.

[0137] The first tool 620 and the second tool 622 can be configured to selectively interact with a surface such as a surface of the painted vehicle 601. The first tool 620 can be a backup pad configured to hold an abrasive for sanding, grinding and the like, in one embodiment, oranother suitable abrasive tool. During an abrasive operation, the first tool 620 via an abrasive disc, or other suitable abrasive article, can abrade a surface of the painted vehicle 601 to remove material. The first tool 620 can be attached to the assembly 618 using adhesive, hook and loop, clip system, vacuum, or other suitable attachment system. Similarly, the second tool 622 can be a second abrasive tool such as an abrasive pad configured for polishing or buffing the surface of the painted vehicle 601. However, according to further examples the second tool 622 can have other configurations as known in the art such as a wiping medium, finer grain sanding implement, and / or fluid removal tool (vacuum, air knife, etc.), etc. The second tool 622 can be attached to the assembly 618 using adhesive, hook and loop, clip system, vacuum or other suitable attachment system. The first tool 620 can be on an opposing side of the assembly 618 from the second tool 622. The first tool 620 and the second tool 622 can be any of or combination of linear, rotary, orbital or random orbital devices.

[0138] During the paint or clearcoat repair process, fluid may be dispensed on the workpiece prior to, during, or subsequent to the utilization of either of the first tool 620 or the second tool 622. This process fluid may combine with particulate matter from the process to create a slurry. The particulate matter composing this slurry is generally caused by the sanding process, which usually takes place prior to a polishing or buffing step (using the second tool 622, for example). One or more wiping tools or implements (not shown) may be employed to remove the slurry and / or excess liquid as desired.

[0139] During the paint or clearcoat repair process, fluid may be dispensed on the workpiece prior to, during, or subsequent to the utilization of either of the first tool 620 or the second tool 622. This process fluid may combine with particulate matter from the process to create a slurry. The particulate matter composing this slurry is generally caused by the sanding process, which usually takes place prior to a polishing or buffing step (using the second tool 622, for example). One or more wiping tools or implements (not shown) may be employed to remove the slurry and / or excess liquid as desired.

[0140] The one or more cameras 624 can be mounted to the assembly 618 adjacent the first tool 620 and the second tool 622. It can be desirable to mount the one or more cameras 624 on the assembly 618 close to a center of gravity of the assembly 618 as this can reduce likelihood of obstruction and / or unwanted vibration of the one or more cameras 624. The assembly 618 can be pivoted as desired to bring one of the first tool 620, the second tool 622, or the one or more cameras 624 into an interfacing relationship with the surface of the painted vehicle 601. The one or more cameras 624 can be positioned by the robotic repair unit 602 as desired to scan the surface of the painted vehicle 601 in a desired area. The one or more cameras 624 can be include a high resolution (e.g., greater than 12MP) digital camera, for example. The one or morecameras 424 can have a zoom lens, according to some examples. The robotic repair unit 602 can move the one or more cameras 624 toward or away from the surface of the painted vehicle 601 as desired.

[0141] The light (not shown) can be mounted to the assembly 618 adjacent the one or more cameras 624. The light can be a generic white light according to some examples. However, characteristics of the light such as size, color, position relative to the one or more cameras 624, etc. can be modified depending upon different application attributes.

[0142] It is also contemplated that the one or more cameras 624 and / or the light can be mounted to a gantry system or other feature that is coupled to the robotic repair unit 602. Thus, the assembly 618 and / or the end effector 616 could be bypassed and need not be coupled to carry the one or more cameras 624 and / or the light in some arrangements. In such arrangements, the gantry system or other feature may still be manipulated to move with movement of the robotic arms 604, 608.

[0143] Via mounting to the assembly 618, the end effector 616, the force control unit, the robotic arms 604, 608, the first tool 420 and the second tool 422, and the one or more cameras 424 have the ability to be positioned within the provided degrees of freedom by the robotic repair unit 602 (6 degrees of freedom in most cases) and any other degrees of freedom (e.g., a compliant force control unit) with its reference frame. This arrangement can allow for positioning of the first tool 620 and the second tool 622, and the one or more cameras 624 as desired to perform repair and imaging. The one or more cameras 624 and the light can also be manipulated to be swept over the surface of the painted vehicle 601 to gather images from multiple positions.

[0144] The robotic paint inspection and repair system 600 can differ from those of previous systems or apparatuses in that the one or more cameras 624 can be implemented on a separate robot assembly from the robotic repair apparatus. The one or more cameras 624 may not be directly mounted to the robotic repair unit 602, the one or more cameras 624 are in close proximity thereto when the robotic repair unit 602 performs polishing, sanding, etc.

[0145] The robotic repair unit 602 and the robotic inspection unit 606 may have a base fixed to a rail system configured to travel along with a vehicle being repaired. However, the arms 604, 608 and other components can be moveable as discussed previously. Depending on a defect location, the robotic repair unit 602 and the robotic inspection unit 606 may need to move closer, or further away from a vehicle, or may need to move higher or lower with respect to the vehicle. FIG. 6 shows a Cartesian coordinate system illustrated for reference with x-axis, y-axis, and z-axis. It is recognized that according to some examples the robotic inspection unit 606 may not be offset across the vehicle in the y-axis direction from the robotic repair unit. Rather, therobotic inspection unit 606 can be placed in another location such as on the same side of the vehicle as the robotic repair unit 602 and offset in the x-axis direction, for example. The position of the first tool 420 and the second tool 422 can be varied by manipulation as previously described.

[0146] FIG. 7 illustrates a method 700 of detecting a defect on a surface, according to embodiments of the present disclosure. The method 700 may be performed by any of the robotic abrading systems described herein, however it is expressly noted that method 700 is not bound to the systems described herein and may also be implemented using another suitable system.

[0147] In block 702, an imaging system is positioned proximate the surface. The imaging system includes a light source having a fringe pattern. The fringe pattern may include a plurality of alternating dark and light portions. The fringe pattern has a ratio of dark portions to light portions of at least 1.5. In some embodiments, the ratio of dark portions to light portions may be at least 1.8, at least 2.0, at least 2.5, or at least 3.0. The fringe pattern 111 may have a greater ratio of dark portion to light portion (i.e., greater than 1.5) than a conventional fringe pattern (e g-, 1).

[0148] The imaging system further includes a camera. In some embodiments, the camera may be a video camera. In some embodiments, the camera may include a varifocal lens. The camera is positioned at an angle with respect to the surface. The angle is between 30° and 90°, measured from perpendicular to the surface. Hereinafter, any angle described with respect to the surface is considered to be measured from the perpendicular or relative to the normal to the surface.

[0149] In some embodiments, the surface may be a semi-diffuse surface. In some embodiments, the surface may be a diffuse surface. The surface (which may be a diffuse or semi-diffuse surface in some examples) may reflect the fringe pattern more specularly at angles between 30° and 90° with respect to the surface than at angles less than 30° with respect to the surface. Furthermore, at angles between 30° and 90° with respect to the surface, undesired illumination of the dark portions of the fringe pattern may reduce. Therefore, the camera being positioned at an angle of between 30° and 90° with respect to the surface may facilitate capturing images of the displayed fringe pattern.

[0150] In some embodiments, the camera may be positioned at an angle of between 45° and 90° with respect to the surface. In some embodiments, the camera may be positioned at an angle of between 60° and 90° with respect to the surface. In some embodiments, the camera may be positioned at an angle of between 75° and 90° with respect to the surface.

[0151] In block 704, images of the surface are captured using the imaging system. Specifically, the camera of the imaging system may capture images of the fringe pattern reflected by the surface.

[0152] In block 706, the images are analyzed and the defect on the surface is detected based on the analysis. Defects on the surface may cause interruptions in the fringe pattern reflected by the surface. Such interruptions may be detected in the images of the fringe pattern to detect the defects. Specifically, in some embodiments, analyzing may include detecting an interruption in the fringe pattern in the captured images. The method 700 may employ an image analyzer that is configured to detect interruptions in the fringe pattern in the captured images to detect defects on the surface.

[0153] In block 708, a defect characteristic for the detected defect is output. The defect characteristic may include a detected location of the defect on the surface, a detected size of the defect, a detected type of the defect, or a detected depth of the defect with respect to the surface. The detected type of defect may include, for example, scratches, presence of undesired or foreign material, craters, etc. The method 700 may employ a defect characterizer to determine the defect characteristic for the detected defect.

[0154] In some embodiments, the surface may be a multilayered surface. The detected depth of the defect may include an indication of a layer of the multilayered surface including the defect. For example, the defect characterizer may characterize that the defect is in a basecoat layer of a multilayered paint surface.

[0155] The method 700 may be used to obtain improved detection of the defect on the surface. Specifically, the fringe pattern having a ratio of dark portions to light portions of at least 1.5 may reduce resolution demands for the camera, without requiring excessive exposure (excessive exposure requirements may limit defect characterization). This may facilitate distinguishing between the dark and light portions of the fringe pattern with suitable properties (e.g., resolution, aperture, and exposure) of the camera, thereby improving defect detection. For example, as compared to a conventional fringe pattern, the fringe pattern may allow the camera to have a wider aperture, a reasonable exposure, and a reasonable resolution, especially if the fringe patterns have a small fringe period (e.g., less than 10 millimeters).

[0156] Moreover, the method 700 may be suitable for detecting defects on diffuse or semidiffuse surfaces. The camera being positioned at an angle of between 30° and 90° with respect to a normal to a diffuse surface may improve detection of small or micro defects on the diffuse surface. The camera, when positioned at an angle of between 30° and 90° with respect to the normal to the surface, may capture improved image(s) of the projected fringe pattern, even in the case of the surface being diffuse or semi-diffuse. The fringe pattern and the positioning of thecamera may together enable detecting defects on diffuse or semi-diffuse surfaces. For example, the method 700 may be used to detect defects on a partially diffuse or primarily diffuse primer coat.

[0157] In some embodiments, the fringe pattern may include a fringe period of at least 1 millimeter (mm), at least 2 mm, at least 3 mm, at least 4 mm, or at least 5 mm. In some embodiments, the fringe pattern may include a fringe period of less than 10 mm or less than 8 mm. As the fringe period decreases, a number of dark and light portions of the fringe pattern per unit length may increase. The fringe period of the fringe pattern being greater than 1 mm and less than 10 mm may provide a suitable number of dark and light portions per defect, thereby improving defect detection.

[0158] The camera may be selected or configured to further reduce detection of diffuse reflections from the surface. In some embodiments, the camera may include an F stop of at least 8, at least 10, at least 15, or at least 20. In some embodiments, the camera may include an F stop of less than 25. An F stop of at least 8 may limit the range of emission angles received by the camera for each pixel, which may reduce detection of light from ambient environment or distant portions of the surface. In conjunction with the fringe pattern and the aforementioned angle of the camera with respect to the surface, this may further improve accuracy and precision of detecting defects.

[0159] In some embodiments, outputting (in block 708) may include sending a control signal to a defect repair system. The control signal may include the defect characteristic. The defect repair system may use the defect characteristic to adjust one or more parameters (e.g., angle, applied pressure, or speed) thereof for surface repairment.

[0160] In some embodiments, the method 700 may further include generating a repair strategy based on the detected defect. The repair strategy may include operational parameters (e.g., angle, applied pressure, or speed) for an abrasive tool used by a defect repair system, which may be generated based on the detected defect. In some embodiments, the abrasive tool may be a sanding tool. In some embodiments, outputting (in block 708) may include communicating the repair strategy to a controller of the defect repair system. For example, the repair strategy may be communicated to the robotic abrading system 100 of FIG. 1.

[0161] In some embodiments, a robotic arm may include the defect repair system and the imaging system. In some embodiments, the method 700 may further include switching a configuration of a robotic repair system from an imaging configuration to a repair configuration. A mode changing mechanism may be configured to switch the configuration of the robotic repair system from the imaging configuration to the repair configuration.

[0162] Switching the robotic repair system from the imaging configuration to the repair configuration may include moving the imaging system away from the surface. The mode changing mechanism may move the imaging system away from the surface. Switching the robotic repair system from the imaging configuration to the repair configuration may further include moving a repair tool to a position proximate the surface. The mode changing mechanism may move an abrasive tool to the position proximate the surface. Specifically, the position may be proximate a detected location of the detected defect.

[0163] In some embodiments, the method 700 may further include contacting the surface at the position with the repair tool. The method 700 may further include abrading the surface with the repair tool. Abrading may include moving the repair tool across the surface with a movement mechanism and applying a force to the tool using a force compliance unit. In this way, the method 700 may include performing a repair process for repairing the detected defect. The repair process may be based on the defect characteristic to further improve surface repairment.

[0164] FIG. 8 illustrates a method 800 for abrading a semi-diffuse surface, according to embodiments of the present disclosure. The method 800 may be performed by the robotic abrading system 100 of FIG. 1 and / or at least partially performed by the defect detection system 200 of FIG. 2.

[0165] In block 802, the semi-diffuse surface is imaged. Block 802 includes sub-blocks 804, 806, 808.

[0166] In sub-block 804, a first image capturing device is positioned proximate the semidiffuse surface. The first image capturing may include a camera or a video camera. In some embodiments, the first image capturing device may include a varifocal lens.

[0167] In some embodiments, the first image capturing device may be positioned at an angle of between 30° and 90° with respect to the semi-diffuse surface, measured from perpendicular to the semi-diffuse surface. As will be discussed later, positioning the first image capturing device at an angle of between 30° and 90° with respect to the semi-diffuse surface, measured from perpendicular to the semi -diffuse surface may provide certain benefits. Hereinafter, any angle described with respect to the semi-diffuse surface is considered to be measured from the perpendicular or relative to the normal to the semi-diffuse surface.

[0168] In sub-block 806, a fringe pattern is projected onto the semi-diffuse surface. The fringe pattern may include a plurality of alternating dark and light portions. The fringe pattern includes a ratio of dark portions to light portions of at least 1.5. The width of each dark portion may be greater than or equal to 1.5 times the width of each light portion. In some embodiments, the ratio of dark portions to light portions may be at least 1.8, at least 2.0, at least 2.5, or at least3.0. The fringe pattern may have a greater ratio of dark portion to light portion (i.e., greater than 1.5) than a conventional fringe pattern (e.g., 1).

[0169] In sub-block 808, the projected fringe pattern is imaged. The first image capturing device may capture images of the fringe pattern reflected by the semi-diffuse surface.

[0170] As discussed above, in some embodiments, the first image capturing device may be positioned at an angle of between 30° and 90° with respect to the semi-diffuse surface, measured from perpendicular to the semi-diffuse surface. The semi-diffuse surface may reflect the fringe pattern more specularly at angles between 30° and 90° with respect to the semi-diffuse than at angles less than 30° with respect to the semi-diffuse surface. Furthermore, at angles between 30° and 90° with respect to the semi-diffuse surface, undesired illumination of the dark portions of the fringe pattern may reduce. Therefore, the first image capturing device being positioned at an angle of between 30° and 90° with respect to the semi-diffuse surface may facilitate capturing images of the projected fringe pattern.

[0171] In some embodiments, the first image capturing device may be positioned at an angle of between 45° and 90° with respect to the semi-diffuse surface, measured from perpendicular to the semi-diffuse surface. In some embodiments, the first image capturing device may be positioned at an angle of between 60° and 90° with respect to the semi-diffuse surface, measured from perpendicular to the semi-diffuse surface. In some embodiments, the first image capturing device may be positioned at an angle of between 75° and 90° with respect to the semi-diffuse surface, measured from perpendicular to the semi-diffuse surface.

[0172] In block 810, a defect at a defect location on the semi-diffuse surface is detected based on the imaged fringe pattern. Defects on the semi-diffuse surface may cause interruptions in the fringe pattern reflected by the semi-diffuse surface. Such interruptions may be detected in the images of the fringe pattern to detect the defects and the defect locations. Specifically, in some embodiments, detecting may include detecting an interruption in the fringe pattern in the captured image. The method 800 may employ an image analyzer that is configured to detect interruptions in the fringe pattern in the captured images to detect defects on the semi-diffuse surface.

[0173] In block 812, the semi-diffuse surface is abraded with an abrasive tool at the defect location. The abrading tool may be of any suitable type, such as an abrasive pad, an abrasive disc, and so forth. In some embodiments, the abrasive tool may include a sanding tool.

[0174] In some embodiments, abrading the semi-diffuse surface may include contacting the semi-diffuse surface at the defect location with the abrasive tool. In some embodiments, contacting may further include applying a force against the abrasive tool using a force compliance unit. In some embodiments, abrading the semi-diffuse surface may further includemoving the abrasive tool against the semi-diffuse surface. The abrasive tool may be moved against the semi-diffuse surface using any suitable motion, such as linear, rotary, or random motion. Specifically, moving may include linear movement, rotational movement, orbital movement, or random orbital movement. The application of the force to the abrasive tool, along with the movement of the abrasive tool across the semi-diffuse surface, may cause the abrasive tool to abrade a portion of the surface at the location of the detected defect.

[0175] In block 814, the semi-diffuse surface is imaged after the abrading operation. Specifically, after the abrading operation, an image capturing device may be positioned proximate the semi-diffuse surface, a fringe pattern may be projected onto the semi-diffuse surface, and the projected fringe pattern may be imaged.

[0176] In block 816, the abrading operation is evaluated. Specifically, the abrading operation may be evaluated based on the projected fringe pattern imaged after the abrading operation (in block 814).

[0177] In some embodiments, evaluating the abrading operation may include imaging the semi-diffuse surface with a second image capturing device proximate the defect location. Evaluating may further include evaluating whether the detected defect was sufficiently repaired. If no defects or defect remnants are detected after the abrading operation, then the abrading operation may be considered as sufficient. In contrast, if one or more defects are detected after the abrading operation, then the abrading operation may need to be reperformed.

[0178] In some embodiments, the second image capturing device may be the first image capturing device. In other words, in some embodiments, the first image capturing device may image the semi-diffuse surface before and after the abrading operation for evaluation.

[0179] The method 800 may be used to repair the semi-diffuse surface by abrading the semidiffuse surface at the defect location. Further, the method 800 may be used to evaluate whether the abrading process has sufficiently repaired the detected defect on the semi-diffuse surface. For example, the method 800 may be used to perform a paint or clearcoat repair process.

[0180] The method 800 may utilize various improved image analysis parameters for detection of the defect on the semi-diffuse surface. Specifically, the fringe pattern having a ratio of at least 1.5 dark to light portions may reduce resolution demands for the first image capturing device, without requiring excessive exposure (excessive exposure requirements may limit defect characterization). This may facilitate distinguishing between the dark and light portions of the fringe pattern with suitable properties (e.g., resolution, aperture, and exposure) of the first image capturing device, thereby improving defect detection. For example, as compared to a conventional fringe pattern, the fringe pattern may allow the first image capturing device to have a wider aperture, a reasonable exposure, and a reasonable resolution, especially if the fringepatterns have a small fringe period (e.g., less than 10 millimeters fringe period). Further, in some embodiments, the first image capturing device being positioned at an angle of between 30° and 90° with respect to a normal to the semi-diffuse surface may improve detection of small or micro defects on the semi-diffuse surface. The fringe pattern and the positioning of the first image capturing device may together enable detecting defects on the semi-diffuse surface.

[0181] In some embodiments, the fringe pattern may include a fringe period of at least 1 millimeter (mm), at least 2 mm, at least 3 mm, at least 4 mm, or at least 5 mm. In some embodiments, the fringe pattern may include a fringe period of less than 10 mm or less than 8 mm. As the fringe period decreases, a number of dark and light portions of the fringe pattern per unit length may increase. The fringe period of the fringe pattern being greater than 1 mm and less than 10 mm may provide a suitable number of dark and light portions per defect, thereby improving defect detection.

[0182] Furthermore, the first and / or second image capturing device may be selected or configured to further reduce detection of diffuse reflections from the semi-diffuse surface. In some embodiments, the first image capturing device may include an F stop of at least 8, at least 10, at least 15, or at least 20. In some embodiments, the first image capturing device may include an F stop of less than 25. An F stop of at least 8 may limit the range of emission angles received by the first image capturing device for each pixel, which may reduce detection of light from ambient environment or distant portions of the semi-diffuse surface. In conjunction with the fringe pattern and the aforementioned angle of the first image capturing device with respect to the semi-diffuse surface, this may improve accuracy and precision of detecting defects.

[0183] As discussed above, the first image capturing device is positioned proximate the semi-diffuse surface. In some embodiments, the first image capturing device may be positioned on a motive robotic arm. That is, positioning the first image capturing device proximate the semi-diffuse surface may include the motive robotic arm positioning the first image capturing device proximate the semi-diffuse surface. Furthermore, in some embodiments, positioning may include the motive robotic arm positioning the first image capturing device at an angle with respect to the semi-diffuse surface, the angle being between 30° and 90°.

[0184] In some embodiments, positioning may further include automatically positioning the first image capturing device based on location data regarding the semi-diffuse surface. In some embodiments, the location data may be absolute position data. In some other embodiments, the location data may be relative to a location of the motive robot arm. For example, a robotic controller may be configured to control the robotic arm to position the first image capturing device at the position based on the location data.

[0185] In some embodiments, the motive robotic arm may further include the abrasive tool (that is used for abrading the semi-diffuse surface). In some embodiments, before abrading the semi-diffuse surface, the method 800 may further include changing a configuration of the motive robotic arm from an imaging configuration to an abrading configuration. Changing the configuration may include rotating an end-effector of the motive robotic arm to move the abrading tool closer to the semi -diffuse surface and the first image capturing device away from the semi-diffuse surface.

[0186] The method 800 may further include characterizing the detected defect. In some embodiments, the defect characteristic may include a detected size of the defect, a detected type of the defect, or a detected depth of the defect with respect to the semi-diffuse surface.

[0187] The method 800 may further include characterizing the semi-diffuse surface proximate the detected defect. In some embodiments, the surface characteristic may include a degree of surface curvature at the defect location. The surface characteristic may further include a specularity or glossiness of the surface. In some examples, the method 800 may further include adjusting the fringe pattern and / or the angle of the first image capturing device with respect to the surface based on the surface characteristic.

[0188] In some embodiments, the method 800 may further include generating an abrasive plan for the detected defect based on the defect characteristic. In some embodiments, the abrasive plan may be generated further based on a detected surface characteristic of the semidiffuse surface proximate the detected defect.

[0189] As discussed above, the semi-diffuse surface is abraded with an abrasive tool at the defect location. In some embodiments, abrading the semi-diffuse surface may include executing the generated abrasive plan with the abrasive tool. In some embodiments, abrading the semidiffuse surface may include automatically executing the generated abrasive plan with the abrasive tool. For example, the abrasive strategy may be communicated to a controller of a defect repair system, such as the robotic abrading system 100 of FIG. 1. A control signal may be transmitted to the defect repair system to instruct the defect repair system to implement the generated abrasive plan.

[0190] FIG. 9 is a networked architecture 900 for a defect detection system 910.Architecture 900 illustrates one embodiment of an implementation of the defect detection system 910, however others are possible. In various embodiments, remote servers can deliver the services over a wide area network, such as the internet, using appropriate protocols. For instance, remote servers can deliver applications over a wide area network, and they can be accessed through a web browser or any other computing component.

[0191] Software or components, as well as the corresponding data, can be stored on servers at a remote location. The computing resources in a remote server environment can be consolidated at a remote data center location or they can be dispersed. Remote server infrastructures can deliver services through shared data centers, even though they appear as a single point of access for the user. Thus, the components and functions described herein can be provided from a remote server at a remote location using a remote server architecture.Alternatively, they can be provided by a conventional server, installed on client devices directly, or in other ways.

[0192] As described herein, defect detection system 910 selects operational settings for components of a robotic abrading system based on information received from an image capturing device 970 which may detect information about defect of a surface. As illustrated, defect detection system 910 may communicate directly with the image capturing device 970, in some embodiments herein.

[0193] FIG. 9 specifically shows that a system 910 can be located at a remote server location 902. Therefore, computing device 920 accesses those systems through remote server location 902. User 950 can use computing device 920 to access user interfaces 922 as well. For example, user interface 922 may provide an information of the defects present on a surface.

[0194] FIG. 9 shows that it is also contemplated that some elements of systems described herein are disposed at remote server location 902 while others are not. By way of example, storage 930, machine learning model 940, or image capturing device 970 can be disposed at a location separate from location 902 and accessed through the remote server at location 902. Regardless of where they are located, they can be accessed directly by computing device 920, through a network (either a wide area network or a local area network), hosted at a remote site by a service, provided as a service, or accessed by a connection service that resides in a remote location. Also, the data can be stored in substantially any location and intermittently accessed by, or forwarded to, interested parties. For instance, physical carriers can be used instead of, or in addition to, electromagnetic wave carriers.

[0195] It will also be noted that the elements of systems described herein, or portions of them, can be disposed on a wide variety of different devices. Some of those devices include servers, desktop computers, laptop computers, imbedded computer, industrial controllers, tablet computers, or other mobile devices, such as palm top computers, cell phones, smart phones, multimedia players, personal digital assistants, etc.

[0196] FIG. 10 shows that a device 1000 can be a smart phone 1071. Smart phone 1071 has a touch sensitive display 1073 that displays icons or tiles or other user input mechanisms 1075. Mechanisms 1075 can be used by a user to run applications, make calls, perform data transferoperations, etc. In general, smart phone 1071 is built on a mobile operating system and offers more advanced computing capability and connectivity than a feature phone. Note that other forms of the devices 1071 are possible.

[0197] FIG. 11 illustrates an example computing device that can be used in embodiments shown in previous Figures. FIG. 11 is one example of a computing environment 1100 in which elements of systems and methods described herein, or parts of them (for example), can be deployed. With reference to FIG. 11, an example system for implementing some embodiments includes a general-purpose computing device in the form of a computer 1110. Components of computer 1110 may include, but are not limited to, a processing unit 1120 (which can comprise a processor), a system memory 1130, and a system bus 1121 that couples various system components including the system memory to the processing unit 1120. The system bus 1121 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. Memory and programs described with respect to systems and methods described herein can be deployed in corresponding portions of FIG. 11.

[0198] Computer 1110 typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by computer 1110 and includes both volatile / nonvolatile media and removable / non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media is different from, and does not include a modulated data signal or carrier wave. It includes hardware storage media including both volatile / nonvolatile and removable / non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computer 1110. Communication media may embody computer readable instructions, data structures, program modules or other data in a transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal.

[0199] The system memory 1130 includes computer storage media in the form of volatile and / or nonvolatile memory such as read only memory (ROM) 1131 and random access memory (RAM) 1132. A basic input / output system 1133 (BIOS) containing the basic routines that helpto transfer information between elements within computer 1110, such as during start-up, is typically stored in ROM 1131. RAM 1132 typically contains data and / or program modules that are immediately accessible to and / or presently being operated on by processing unit 1120. By way of example, and not limitation, FIG. 12 illustrates operating system 1134, application programs 1135, other program modules 1136, and program data 1137.

[0200] The computer 1110 may also include other removable / non-removable and volatile / nonvolatile computer storage media. By way of example only, FIG. 11 illustrates a hard disk drive 1141 that reads from or writes to non-removable, nonvolatile magnetic media, nonvolatile magnetic disk 1152, an optical disk drive 1155, and nonvolatile optical disk 1156. The hard disk drive 1141 is typically connected to the system bus 1121 through a non-removable memory interface such as interface 1140, and optical disk drive 1155 are typically connected to the system bus 1121 by a removable memory interface, such as interface 1150.

[0201] Alternatively, or in addition, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (e.g., ASICs), Applicationspecific Standard Products (e.g., ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), etc.

[0202] The drives and their associated computer storage media discussed above and illustrated in FIG. 11, provide storage of computer readable instructions, data structures, program modules and other data for the computer 1110. In FIG. 11, for example, hard disk drive 1141 is illustrated as storing operating system 1144, application programs 1145, other program modules 1146, and program data 1147. Note that these components can either be the same as or different from operating system 1134, application programs 1135, other program modules 1136, and program data 1137.

[0203] A user may enter commands and information into the computer 1110 through input devices such as a keyboard 1162, a microphone 1163, and a pointing device 1161, such as a mouse, trackball or touch pad. Other input devices (not shown) may include a joystick, game pad, satellite receiver, scanner, or the like. These and other input devices are often connected to the processing unit 1120 through a user input interface 1160 that is coupled to the system bus, but may be connected by other interface and bus structures. A visual display 1191 or other type of display device is also connected to the system bus 1121 via an interface, such as a video interface 1190. In addition to the monitor, computers may also include other peripheral output devices such as speakers 1197 and printer 1196, which may be connected through an output peripheral interface 1195.

[0204] The computer 1110 is operated in a networked environment using logical connections, such as a Local Area Network (LAN) or Wide Area Network (WAN) to one or more remote computers, such as a remote computer 1180.

[0205] When used in a LAN networking environment, the computer 1110 is connected to the LAN 1171 through a network interface or adapter 1170. When used in a WAN networking environment, the computer 1110 typically includes a modem 1172 or other means for establishing communications over the WAN 1173, such as the Internet. In a networked environment, program modules may be stored in a remote memory storage device. FIG. 11 illustrates, for example, that remote application programs 1185 can reside on remote computer 1180.

[0206] It will be apparent to those skilled in the art that the specific exemplary embodiments, elements, structures, features, details, arrangements, configurations, etc., that are disclosed herein can be modified and / or combined in numerous ways. In summary, numerous variations and combinations are contemplated as being within the bounds of the conceived invention, not merely those representative designs that were chosen to serve as exemplary illustrations. Thus, the scope of the present invention should not be limited to the specific illustrative structures described herein, but rather extends at least to the structures described by the language of the claims, and the equivalents of those structures. Any of the elements that are positively recited in this specification as alternatives may be explicitly included in the claims or excluded from the claims, in any combination as desired. Any of the elements or combinations of elements that are recited in this specification in open-ended language (e.g., comprise and derivatives thereof), are considered to additionally be recited in closed-ended language (e.g., consist and derivatives thereof) and in partially closed-ended language (e.g., consist essentially, and derivatives thereof). Although various theories and possible mechanisms may have been discussed herein, in no event should such discussions serve to limit the claimable subject matter. To the extent that there is any conflict or discrepancy between this specification as written and the disclosure in any document that is incorporated by reference herein but to which no priority is claimed, this specification as written will control. In the present detailed description of the preferred embodiments, reference is made to the accompanying drawings, which illustrate specific embodiments in which the invention may be practiced. The illustrated embodiments are not intended to be exhaustive of all embodiments according to the invention. It is to be understood that other embodiments may be utilized, and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0207] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

[0208] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and / or” unless the content clearly dictates otherwise.

[0209] Spatially related terms, including but not limited to, “proximate,” “distal,” “lower,” “upper,” “beneath,” “below,” “above,” and “on top,” if used herein, are utilized for ease of description to describe spatial relationships of an element(s) to another. Such spatially related terms encompass different orientations of the device in use or operation in addition to the particular orientations depicted in the figures and described herein. For example, if an object depicted in the figures is turned over or flipped over, portions previously described as below or beneath other elements would then be above or on top of those other elements.

[0210] As used herein, when an element, component, or layer for example is described as forming a “coincident interface” with, or being “on,” “connected to,” “coupled with,” “stacked on” or “in contact with” another element, component, or layer, it can be directly on, directly connected to, directly coupled with, directly stacked on, in direct contact with, or intervening elements, components or layers may be on, connected, coupled or in contact with the particular element, component, or layer, for example. When an element, component, or layer for example is referred to as being “directly on,” “directly connected to,” “directly coupled with,” or “directly in contact with” another element, there are no intervening elements, components, or layers for example.

[0211] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

CLAIMS:What is claimed is:

1. A method of detecting a defect on a surface, the method comprising: positioning an imaging system proximate the surface, wherein the imaging system comprises: a light source having a fringe pattern, the fringe pattern having a ratio of dark portions to light portions of at least 1.5; and a camera positioned at an angle with respect to the surface, the angle being between 30° and 90°, measured from perpendicular to the surface; capturing images of the surface, using the imaging system; analyzing the images, and based on the analysis, detecting the defect on the surface; and outputting a defect characteristic for the detected defect.

2. The method of claim 1, wherein the defect characteristic comprises a detected location of the defect on the surface, a detected size of the defect, a detected type of the defect, or a detected depth of the defect with respect to the surface.

3. The method of claim 1, and further comprising, based on the detected defect, generating a repair strategy, and wherein outputting comprises communicating the repair strategy to a controller of a defect repair system.

4. The method of claim 3, wherein a robotic arm comprises the defect repair system and the imaging system.

5. The method of claim 3, and further comprising: switching a configuration of a robotic repair system from an imaging configuration to a repair configuration, wherein switching comprises moving the imaging system away from the surface, and moving a repair tool to a position proximate the surface.

6. The method of claim 5, and further comprising: contacting the surface, at the position, with the repair tool, wherein the position is proximate a detected location of the detected defect; andabrading the surface with the repair tool, wherein abrading comprises moving the repair tool across the surface, with a movement mechanism and applying a force to the tool, using a force compliance unit.

7. The method of claim 1, wherein the ratio of dark portions to light portions is at least 1.8.

8. The method of claim 1, wherein the fringe pattern comprises a fringe period of at least 1 mm.

9. The method of claim 1, wherein the fringe pattern comprises a fringe period of less than 10 mm.

10. The method of claim 1, wherein the camera comprises an F stop of at least 8.

11. The method of claim 1, wherein the camera comprises an F stop of less than 25.

12. The method of claim 1, wherein analyzing comprises detecting an interruption in the fringe pattern in the captured images.

13. The method of claim 1, wherein the camera is positioned at an angle of between 45° and 90° with respect to the surface.

14. A robotic abrading system comprising: an imaging system configured to: project, using a light source, a fringe pattern onto a surface, wherein the fringe pattern has a ratio of at least 1.5 dark to light portions; capture, using an image capturing device, an image of the displayed fringe pattern on the surface, wherein an image capturing device positioning mechanism positions the image capturing device at an angle with respect to the surface, wherein the angle is between 30° and 90°, measured from perpendicular to the surface; analyze, using an image analyzer, the captured image and detect a defect on the surface; and determine a defect characteristic for the detected defect based on the analysis; an abrading system configured to:move, using a tool movement system, an abrasive tool proximate a location of the detected defect; move, using an abrasive movement mechanism, the abrasive tool across the surface, over the location of the detected defect; and apply a force to the abrasive tool, using a force compliance tool.

15. The robotic abrading system of claim 14, wherein a motive robotic arm comprises the imaging system and the abrading system, and further comprising a mode changing mechanism that changes the robotic arm from an imaging mode, where the image capturing device is proximate the surface, to an abrading mode, where the abrasive tool is proximate the surface.

16. The robotic abrading system of claim 15, wherein the robotic arm comprises an endeffector, and wherein the end-effector comprises the abrasive movement mechanism.

17. The robotic abrading system of claim 14, wherein the defect characteristic comprises a detected location of the defect on the surface, a detected size of the defect, a detected type of the defect, or a detected depth of the defect with respect to the surface.

18. The robotic abrading system of claim 14, and further comprising an abrasive strategy generator configured to, based on the defect characteristic, generate an abrasive strategy for the abrasive tool.

19. The robotic abrading system of claim 14, wherein the ratio of dark portions to light portions is at least 1.8.

20. The robotic abrading system of claim 14, wherein the fringe pattern comprises a fringe period of at least 1 mm.

21. The robotic abrading system of claim 14, wherein the fringe pattern comprises a fringe period of less than 10 mm.

22. The robotic abrading system of claim 14, wherein the image capturing device comprises an F stop of at least 8.

23. The robotic abrading system of claim 14, wherein the image capturing device comprises an F stop of less than 25.

24. The robotic abrading system of claim 14, wherein analyzing comprises detecting an interruption in the fringe pattern in the captured images.

25. The robotic abrading system of claim 14, wherein the image capturing device is positioned at an angle of between 45° and 90° with respect to the surface.

26. A method of abrading a semi-diffuse surface, the method comprising: imaging the semi-diffuse surface, wherein imaging the semi-diffuse surface comprises: positioning a first image capturing device proximate the semi -diffuse surface; projecting a fringe pattern onto the semi-diffuse surface, wherein the fringe pattern comprises a ratio of dark portions to light portions of at least 1.5; and imaging the projected fringe pattern; detecting, based on the imaged fringe pattern, a defect at a defect location on the semidiffuse surface; abrading the semi-diffuse surface, with an abrasive tool, at the defect location; imaging the semi-diffuse surface after the abrading operation; and evaluating the abrading operation.

27. The method of claim 26, wherein evaluating comprises: imaging, with a second image capturing device, the semi-diffuse surface proximate the defect location; and evaluating whether the detected defect was sufficiently repaired.

28. The method of claim 27, wherein the second image capturing device is the first image capturing device.

29. The method of claim 26, wherein the first image capturing device is positioned on a motive robotic arm, and wherein positioning the first image capturing device proximate the semi-diffuse surface comprises the motive robotic arm positioning the first image capturing device proximate the semi-diffuse surface.

30. The method of claim 29, wherein positioning comprises the motive robotic arm positioning the first image capturing device at an angle with respect to the semi-diffuse surface, the angle being between 30° and 90°.

31. The method of claim 29, wherein positioning comprises automatically positioning the first image capturing device based on location data regarding the semi-diffuse surface.

32. The method of claim 29, wherein the motive robotic arm comprises the abrasive tool.

33. The method of claim 32, wherein the method further comprises: before abrading the semi-diffuse surface, changing a configuration of the motive robotic arm from an imaging configuration to an abrading configuration.

34. The method of claim 26, wherein abrading the semi-diffuse surface comprises contacting the semi-diffuse surface, at the defect location, with the abrasive tool.

35. The method of claim 34, wherein abrading the semi-diffuse surface further comprises moving the abrasive tool against the semi-diffuse surface wherein moving comprises linear movement, rotational movement, orbital movement, or random orbital movement.

36. The method of claim 34, wherein contacting comprises applying a force against the abrasive tool, using a force compliance unit.

37. The method of claim 26, and further comprising characterizing the detected defect, wherein the defect characteristic comprises a detected size of the defect, a detected type of the defect, or a detected depth of the defect with respect to the semi-diffuse surface.

38. The method of claim 36, and further comprising characterizing the semi-diffuse surface proximate the detected defect.

39. The method of claim 38, wherein the surface characteristic comprises a degree of surface curvature at the defect location.

40. The method of claim 26, wherein the abrasive tool comprises a sanding tool.

41. The method of claim 26, wherein the ratio of dark portions to light portions is at least 1.8.

42. The method of claim 26, wherein the fringe pattern comprises a fringe period of less than 10 mm.

43. The method of claim 26, wherein the first image capturing device comprises an F stop of less than 25.

44. The method of claim 26, wherein detecting comprises detecting an interruption in the fringe pattern in the captured image.

45. The method of claim 26, wherein the first image capturing device is positioned at an angle of between 30° and 90° with respect to the semi-diffuse surface, measured from perpendicular to the semi-diffuse surface.

46. A defect detection system comprising: a light source configured to project a fringe pattern onto a surface, wherein the fringe pattern comprises a ratio of dark portions to light portions of at least 1.5, and wherein the fringe pattern has a fringe period of at least 1 mm; an image capturing device configured to capture an image of the projected fringe pattern; a movement mechanism configured to move the image capturing device into a position, wherein the position comprises the image capturing device at an angle with respect to the surface, wherein the angle is between 30° and 90°, measured from perpendicular to the surface; an image analyzer configured to, based on the captured image, detect a defect on the surface; a defect characterizer configured to characterize at least one of a location of the defect on the surface, a depth of the defect with respect to the surface, a type of the defect, or a size of the defect; and a communication component configured to report the defect characteristic.

Images