Calibration device and calibration method for roller surface imaging

Abstract

The invention discloses a calibration device and a calibration method for roller surface imaging, and belongs to the technical field of visual inspection. The calibration device for roller surface imaging comprises a calibration tool, an angle gauge and a target, the calibration tool is of a symmetrical structure and comprises a connecting piece and a clamping piece which are connected, the connecting piece is provided with a calibration surface and used for installing a light source, the calibration surface perpendicularly intersects with the symmetrical surface of the calibration tool, and the clamping piece is used for clamping a guide roller; the target is arranged on the connecting piece, extends in the axial direction of the guide roller and is used for being in contact fit with the guide roller, the target is provided with an imaging area, and the imaging area is in mirror symmetry relative to the symmetry plane. The calibration tool and the target are relatively fixed, the attitude of the light source is calibrated by measuring the inclination angle of the calibration surface through the angle gauge, and then the attitude of the camera is calibrated according to the imaging area on the target, so that the precision and reliability of roller surface imaging and the high efficiency and accuracy of the calibration process are realized; and an accurate imaging basis is provided for subsequent defect detection.

Description

Technical Field

[0001] The present application belongs to the field of visual inspection technology, and in particular, relates to a calibration device and a calibration method for roller surface imaging. Background Art

[0002] With the widespread application of machine vision inspection technology, more and more industries have begun to introduce CCD imaging systems to detect defects in production targets to ensure that product quality meets standards. Among them, in the production and processing of roll-type film materials, they are often transported and processed by cylindrical guide rollers. However, since the film material will shake and warp due to the running speed and vibration of the guide roller during the production process, the actual imaging angle of the imaging device is difficult to determine directly through its posture angle, and the imaging angle is different after each adjustment, which is difficult to maintain consistency, affecting the inspection efficiency and accuracy. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a calibration device and a calibration method for roller surface imaging, which can calibrate the posture of the light source and the camera in turn, achieve the accuracy and reliability of roller surface imaging, as well as the efficiency and accuracy of the calibration process, and provide an accurate imaging basis for subsequent defect detection.

[0004] In a first aspect, the present application provides a calibration device for roller surface imaging, comprising:

[0005] A calibration tool, the calibration tool is a symmetrical structure, the calibration tool comprises a connected connecting piece and a clamping piece, the connecting piece has a calibration surface and is used to install the light source, the calibration surface intersects vertically with the symmetry plane of the calibration tool, and the clamping piece is used to clamp the guide roller;

[0006] An inclinometer, used to measure the inclination angle of the calibration surface;

[0007] A target is arranged on the connecting member, the length of the target extends along the axial direction of the guide roller, and is used for contacting and cooperating with the guide roller. The target has an imaging area, and the imaging area is mirror-symmetrical with respect to the symmetry plane.

[0008] According to the calibration device for roller surface imaging of the present application, in actual implementation, the guide roller is clamped by a clamping member, and the guide roller or the calibration tool is rotated until the angle meter displays the target value, and then the relative positions of the calibration tool, the guide roller and the target are fixed. Since the light source is installed on the connecting member, even if the intersection of the center of the light beam emitted by the light source and the roller surface of the guide roller is located within the imaging point section, the calibration of the light source posture is achieved; then, since the target is installed on the connecting member and contacts the guide roller, and the imaging area is mirror-symmetrical with respect to the symmetry plane, the posture of the camera can be adjusted according to the actual image obtained by comparing the imaging area with the original image of the imaging area, until the difference between the actual image and the original image meets the requirements, thereby achieving the calibration of the camera posture.

[0009] According to an embodiment of the present application, the clamping member includes two clamping arms respectively arranged at both ends of the connecting member, and the two clamping arms both have clamping surfaces that are mirror-symmetrical with respect to the symmetry plane, and the clamping surfaces are used to cooperate with the roller surface of the guide roller; wherein,

[0010] The clamping surface is a plane, and the distance between the two clamping surfaces gradually increases in a direction away from the connecting member; or

[0011] The clamping surface is a curved surface, and the center of curvature of the clamping surface is located inside the guide roller.

[0012] According to an embodiment of the present application, the connecting member is provided with a detachable first mounting structure for fixing the light source.

[0013] According to one embodiment of the present application, the first mounting structure includes:

[0014] a first mounting member, the first mounting member being convexly disposed on the calibration surface;

[0015] The second mounting member is used to mount the light source. The second mounting member is mounted on the first mounting member in an adjustable angle. The rotation axis of the second mounting member is parallel to the axial direction and is located in the symmetry plane.

[0016] According to one embodiment of the present application, the second mounting member includes:

[0017] a first section, wherein one end of the first section is mounted on the first mounting member in an angle-adjustable manner;

[0018] The second section is arranged at the other end of the first section, and the extending direction of the first section, the extending direction of the second section and the axial direction are perpendicular to each other.

[0019] According to one embodiment of the present application, the second section is provided with an adjusting member for adjusting the installation position of the light source.

[0020] According to one embodiment of the present application, the connecting member is provided with a detachable second mounting structure for fixing the target.

[0021] According to one embodiment of the present application, the second mounting structure includes:

[0022] A third mounting member, disposed on the connecting member;

[0023] A tensioning assembly is arranged on the third mounting member and is used for tensioning the target.

[0024] According to an embodiment of the present application, the third mounting member includes a main body and two oppositely arranged supporting arms, one end of each supporting arm is connected to the main body and extends along the axial direction; the tensioning assembly includes:

[0025] A first assembly part, installed between the two arms and spaced apart from the main body, and having a first mating surface;

[0026] The second assembly is mounted on the first assembly and has a second mating surface, and the end portion of the target is located between the first mating surface and the second mating surface.

[0027] According to an embodiment of the present application, both the first mating surface and the second mating surface are inclined from a direction away from the main body to a direction close to the guide roller.

[0028] In a second aspect, the present application provides a calibration method using the calibration device for roller surface imaging as described above, the calibration method comprising:

[0029] The calibration tool and the light source are relatively fixed and the calibration tool clamps the guide roller, and the measured value of the inclinometer is equal to the target value;

[0030] The calibration fixture and the guide roller are maintained, and the position and posture of the camera are adjusted based on the imaging area of ​​the target.

[0031] According to the calibration method of the present application, through the above steps and in combination with the above calibration device for roller surface imaging, relevant operators can operate according to standard calibration process steps, reducing the blindness of on-site installation and adjustment, thereby reducing the impact of human factors on imaging quality.

[0032] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0034] Figure 1 is a schematic structural diagram of a calibration device for roller surface imaging provided in an embodiment of the present application;

[0035] Figure 2 It is a structural schematic diagram of the cooperation between the calibration device for roller surface imaging and the matching component provided in the embodiment of the present application;

[0036] Figure 3 It is a schematic diagram of the structure of the target and the calibration tooling provided in the embodiment of the present application;

[0037] Figure 4 is an exploded view of a tensioning assembly provided in an embodiment of the present application;

[0038] Figure 5 It is a schematic diagram of the structure of the imaging area of ​​three targets provided in the embodiments of the present application;

[0039] Figure 6 It is a flow chart of a calibration method using a calibration device for roller surface imaging provided in an embodiment of the present application.

[0040] Reference numerals:

[0041] 100. Calibration tooling;

[0042] 110. Connecting piece; 111. Calibration surface; 121. Clamping arm;

[0043] 200, target; 201, imaging area;

[0044] 210, line pair target; 211, triangle; 2121, sub-segment; 213, second line;

[0045] 220, distorted target; 221, line image;

[0046] 230, white balance target;

[0047] 310, first mounting member; 320, second mounting member;

[0048] 321, first paragraph; 322, second paragraph;

[0049] 400, adjusting member; 410, first part; 420, second part; 430, fixing member;

[0050] 500, second installation structure;

[0051] 510, third mounting member; 511, main body; 512, supporting arm;

[0052] 520, tensioning assembly; 521, first assembly component; 5211, first mating surface; 522, second assembly component;

[0053] 810, light source; 820, camera; 830, matching parts;

[0054] 900, guide roller; 10, section of imaging point. DETAILED DESCRIPTION

[0055] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0056] Reference below Figure 1-Figure 5 The calibration device for roller surface imaging provided in an embodiment of the present application is described. The calibration device for roller surface imaging includes a calibration tool 100 , an inclinometer, and a target 200 .

[0057] The calibration tool 100 is a symmetrical structure. The calibration tool 100 includes a connecting piece 110 and a clamping piece connected to each other. The connecting piece 110 has a calibration surface 111 and is used to install the light source 810. The calibration surface 111 intersects perpendicularly with the symmetry plane of the calibration tool 100. The clamping piece is used to clamp the guide roller 900. The inclinometer is used to measure the inclination angle of the calibration surface 111. The target 200 is set on the connecting piece 110. The length of the target 200 extends along the axial direction of the guide roller 900, and is used to contact and cooperate with the guide roller 900. The target 200 has an imaging area 201, and the imaging area 201 is mirror-symmetrical relative to the symmetry plane. The target 200 and the guide roller 900 are in line contact or surface contact, that is, the symmetry plane sequentially passes through the imaging area 201 of the target 200 and the guide roller 900, so that the contact point between the roller surface and the target 200 is located in the imaging point section 10 (the imaging point section 10 refers to the section formed by the camera 820 and the surface of the guide roller 900). The shape of the target 200 includes but is not limited to a rectangle.

[0058] It should be noted that the angle meter displays the measured value of the angle formed between the calibration surface 111 and the horizontal plane. Since the calibration surface 111 is perpendicular to the symmetry plane of the calibration tool 100, the angle value displayed by the angle meter is also equal to the angle between the symmetry plane and the vertical plane. Since the center line of the calibration tool 100 is in the symmetry plane, the displayed angle value is also equal to the angle between the center line of the calibration tool 100 and the vertical plane. Exemplarily, when the angle between the calibration surface 111 and the horizontal plane displayed by the angle meter is 0, it means that the target 200 is placed directly above the guide roller 900, that is, the imaging point section 10 is parallel to the horizontal plane, and the normal corresponding to the imaging point section 10 is located in the symmetry plane and parallel to the vertical plane. Among them, the angle meter can be installed on the calibration surface 111 or installed outside the calibration tool 100, as long as it can measure the inclination angle between the calibration surface 111 and the horizontal plane, and this embodiment does not impose specific restrictions on this.

[0059] For ease of understanding, during detection, the light source 810 and the camera 820 are located on the same side of the guide roller 900 and on both sides of the normal corresponding to the imaging point section 10. The intersection of the center of the light beam emitted by the light source 810 and the roller surface of the guide roller 900 should also be located within the imaging point section 10 to make the imaging effect better and improve the imaging accuracy and the accuracy of defect detection.

[0060] It can be understood that, in actual implementation, the guide roller 900 is clamped by the clamping member, and the guide roller 900 or the calibration tool 100 is rotated until the inclinometer displays the target value, and then the relative positions of the calibration tool 100, the guide roller 900 and the target 200 are fixed. Since the light source 810 is installed on the connecting member 110, even if the intersection of the center of the light beam emitted by the light source 810 and the roller surface of the guide roller 900 is located within the imaging point section 10, the calibration of the posture of the light source 810 is achieved; then, since the target 200 is installed on the connecting member 110 and contacts the guide roller 900, and the imaging area 201 is mirror-symmetrical with respect to the symmetry plane, the posture of the camera 820 can be adjusted according to the actual image obtained by comparing the imaging area 201 with the calibration image of the imaging area 201 by the camera 820, until the difference between the actual image and the calibration image meets the requirements, thereby achieving the calibration of the posture of the camera 820.

[0061] The calibration device for roller surface imaging provided in the embodiment of the present application, through the relative fixation between the calibration tool 100 and the target 200, first uses the incline angle of the calibration surface 111 to measure the posture of the light source 810 using an inclinometer, and then calibrates the posture of the camera 820 according to the imaging area 201 on the target 200, thereby achieving the accuracy and reliability of roller surface imaging, as well as the efficiency and accuracy of the calibration process, providing an accurate imaging basis for subsequent defect detection.

[0062] In some embodiments, Figures 1 to 3 As shown, the clamping member includes two clamping arms 121 respectively arranged at both ends of the connecting member 110 , and the two clamping arms 121 both have clamping surfaces that are mirror-symmetrical relative to the symmetry plane, and the clamping surfaces are used to cooperate with the roller surface of the guide roller 900 .

[0063] It is understandable that the two clamping arms 121 arranged opposite to each other can closely fit the roller surface of the guide roller 900, ensuring that the calibration tool 100 is fixed on the guide roller 900 more firmly and stably, thereby providing a reliable physical basis for the calibration of the light source 810 and the camera 820. That is, the clamping surface and the roller surface of the guide rail are tangent, and combined with the geometric principle of "three points determine a circle", the imaging point section 10 is determined by the contact points between the two clamping surfaces and the roller surface of the guide roller 900, which can ensure that the symmetry plane can pass through the calibration surface 111 and the central axis of the guide roller 900, so as to accurately determine the position and posture of the calibration tool 100 on the guide roller 900, thereby realizing the subsequent accurate calibration of the light source 810 and the camera 820.

[0064] In some embodiments, Figures 1 to 3 As shown, the clamping surface is a plane, and the distance between the two clamping surfaces gradually increases in the direction away from the connector 110. It should be noted that the inclination angle and size of the clamping surface can be designed according to actual needs, and the symmetry of this embodiment is not specifically limited.

[0065] It can be understood that the two clamping arms 121 can stop against the roller surface of the guide roller 900, that is, the two clamping surfaces are tangent to the roller surface of the guide roller 900. A V-shaped opening for placing the guide roller 900 can be formed between the two clamping surfaces, so as to adapt to guide rollers 900 of different diameters by utilizing the inclined setting of the clamping surfaces, and provide stable support during the clamping process, while facilitating installation and disassembly. That is, the larger the angle of the V-shaped opening, the closer the guide roller 900 is to the connecting piece 110 of the calibration tool 100, and the smaller the angle, the farther the guide roller 900 is from the connecting piece 110 of the calibration tool 100.

[0066] In other embodiments, the clamping surface is a curved surface, and the center of curvature of the clamping surface is located inside the guide roller 900 .

[0067] It can be understood that the center of curvature of the clamping surface is located inside the guide roller 900, so that the clamping surface is more closely fitted to the roller surface of the guide roller 900, increasing the contact area to provide better contact stability and clamping accuracy, making the calibration tooling 100 more firmly and stably fixed on the guide roller 900.

[0068] In some embodiments, Figure 2 As shown, in order to ensure that the position of the calibration tool 100 and the guide roller 900 remains unchanged during the calibration process, a matching piece 830 is provided on the outer side of the guide roller 900. The matching piece 830 is relatively fixedly connected to the connecting piece 110 to play the role of external clamping, thereby improving the accuracy and reliability of the calibration. This connection can be threaded, snap-fit, plug-in or other mechanical connection methods to ensure that the two will not be relatively displaced during the calibration process.

[0069] In some embodiments, Figures 1 to 3As shown, the connector 110 is provided with a detachable first mounting structure for fixing the light source 810. Exemplarily, the first connection structure may be a detachable connector 110, which includes but is not limited to a threaded connector 110, a snap connector 110 or other connectors 110.

[0070] It is understandable that after the calibration tool 100 is placed on the roller surface, the light source 810 can be installed on the connecting member 110 through the above-mentioned first installation structure, and the angle between the calibration surface 111 and the horizontal plane can be measured by using an inclinometer during the subsequent rotation of the calibration tool 100 until it is equal to the preset angle. When the detection is completed, the first installation structure can be disassembled, thereby removing the light source 810 from the calibration tool 100. This improves the overall flexibility of the calibration device for roller surface imaging, and the easy-to-disassemble design also facilitates the subsequent repair, maintenance and storage of the device.

[0071] In some embodiments, Figures 1 to 3 As shown, the first mounting structure includes a first mounting member 310 and a second mounting member 320. The first mounting member 310 is protruded from the calibration surface 111; the second mounting member 320 is used to mount the light source 810, and the second mounting member 320 is installed on the first mounting member 310 with an adjustable angle. The rotation axis of the second mounting member 320 is parallel to the axial direction and is located in the symmetry plane.

[0072] It is understandable that the first mounting member 310 is disposed on the connecting member 110 and protrudes from the calibration surface 111, and is used as a basic support structure for the installation of the light source 810, and ensures that the relative position between the light source 810 and the calibration surface 111 is stable. The second mounting member 320 is mounted on the first mounting member 310 in an adjustable manner, allowing the angle between the center of the light beam emitted by the light source 810 and the intersection of the roller surface of the guide roller 900 and the normal corresponding to the imaging point section 10 to be adjusted according to actual needs before calibrating the light source 810. The rotation axis of the second mounting member 320 is parallel to the axial direction of the guide roller 900 and is located on the symmetry plane of the calibration fixture 100, so as to ensure that when the clamping member clamps the guide roller 900, the intersection of the center of the light beam of the light source 810 and the roller surface of the guide roller 900 is exactly located in the imaging point section 10, thereby enhancing the versatility, flexibility and reliability of the calibration device for roller surface imaging.

[0073] In some embodiments, Figure 1 and Figure 2 As shown, the second mounting member 320 includes a first section 321 and a second section 322, wherein one end of the first section 321 is mounted on the first mounting member 310 with an adjustable angle; the second section 322 is disposed at the other end of the first section 321, and the extension direction of the first section 321, the extension direction of the second section 322 and the axial direction are perpendicular to each other.

[0074] It should be noted that the extension direction of the second section 322 is parallel to the direction in which the center of the light beam of the light source 810 is emitted.

[0075] It can be understood that the second section 322 is located at one end of the first section 321 away from the first mounting member 310, and the extension direction of the first section 321, the extension direction of the second section 322 and the axial direction are perpendicular to each other, that is, the second mounting member 320 is L-shaped, ensuring that the installation position and angle of the light source 810 always remain stable during the calibration process, reducing the possibility of imaging deviation.

[0076] In some embodiments, Figure 1 As shown, the second section 322 is provided with an adjusting member 400 for adjusting the installation position of the light source 810 to accommodate guide rollers 900 and light sources 810 of different specifications, thereby enhancing the versatility and adaptability of the calibration device for roller surface imaging.

[0077] In some embodiments, Figure 1 As shown, the light source 810 is adjustably installed in the second section 322 along the extension direction of the second section 322 so that the light source 810 is close to or away from the guide roller 900, thereby adjusting the irradiation intensity of the light beam.

[0078] In some embodiments, Figure 1 As shown, the adjustment member 400 includes a first portion 410, the first portion 410 is connected to the light source 810 and forms a first slide groove, the second section 322 extends into the first slide groove away from one end of the first section 321, one of the first slide groove and the second section 322 forms a first elongated hole, and the other of the first slide groove and the second section 322 forms a plurality of first mounting holes distributed at intervals, that is, different first mounting holes are matched with the first elongated holes, so that the light source 810 is adjustable in the installation position along the extension direction of the second section 322 and is set in the second section 322. Of course, in other embodiments, it can also be realized by using a threaded adjustment device, an elastic support or other mechanical adjustment mechanism, and this embodiment does not make specific restrictions on this.

[0079] In some embodiments, Figure 1 As shown, the installation position of the light source 810 along the axial direction is adjustably set on the second section 322, so as to adjust the irradiation angle and range of the light beam.

[0080] In some embodiments, Figure 1As shown, the adjusting member 400 also includes a second portion 420 connected to the light source 810, the second portion 420 and the first portion 410 are slidably matched along the axial direction, and the first portion 410 forms a second mounting hole, one end of the fixing member 430 passes through the second mounting hole and is threadedly connected to the second portion 420, that is, after the first portion 410 and the second portion 420 are relatively slid to a suitable position, the second portion 420 is locked in the position by the fixing member 430. The fixing member 430 includes but is not limited to screws or bolts. Of course, in other embodiments, it can also be implemented by a threaded adjustment device, an elastic support or other mechanical adjustment mechanism, and this embodiment does not make specific restrictions on this.

[0081] In some embodiments, Figure 1 As shown, in order to ensure the close fit between the target 200 and the guide roller 900 and the stability of the installation of the light source 810, two calibration fixtures 100 are axially spaced at both ends of the guide roller 900, and the first installation structure corresponds to the calibration fixtures 100 one by one.

[0082] In some embodiments, Figure 3 and Figure 4 As shown, the connecting member 110 is provided with a detachable second mounting structure 500 for fixing the target 200 .

[0083] It can be understood that the second mounting structure 500 corresponds to the calibration fixture 100 one by one. After the calibration fixture 100 is placed on the roller surface, the target 200 can be mounted on the connecting piece 110 through the second mounting structure 500, and the angle between the calibration surface 111 and the horizontal plane is measured by an inclinometer during the subsequent rotation of the calibration fixture 100 until it is equal to the preset angle. After the calibration is completed, the second mounting structure 500 can be disassembled, thereby removing the target 200 from the calibration fixture 100 to reduce the possibility of interference with the product wound on the roller surface. This improves the overall flexibility of the calibration device for roller surface imaging, and the easy-to-disassemble design also facilitates the subsequent repair, maintenance and storage of the device.

[0084] It should be noted that the products include but are not limited to lithium battery films, plastic films or rolls of paper.

[0085] In some embodiments, Figure 3 As shown, the second mounting structure 500 includes a third mounting member 510 , and the third mounting member 510 is disposed on the connecting member 110 ; the tensioning assembly 520 is disposed on the third mounting member 510 for tensioning the target 200 .

[0086] It is understandable that the third mounting member 510 is provided on the connecting member 110 and is used as a basic support structure for mounting the target 200 to ensure that the target 200 remains fixed during the calibration process. At the same time, the end of the target 200 is fixed by the tensioning assembly 520 to ensure that the target 200 remains as flat and stable as possible during the calibration process, thereby reducing the possibility of partial deformation of the target 200 and affecting the imaging.

[0087] In some embodiments, Figure 1 , Figure 3 and Figure 4 As shown, the third mounting member 510 includes a main body 511 and two oppositely arranged arms 512, one end of the arm 512 is connected to the main body 511 and extends axially; the tensioning assembly 520 includes a first assembly member 521 and a second assembly member 522, the first assembly member 521 is installed between the two arms 512 and is spaced from the main body 511, and the first assembly member 521 has a first mating surface 5211; the second assembly member 522 is installed on the first assembly member 521 and has a second mating surface, and the end portion of the target 200 is located between the first mating surface 5211 and the second mating surface. The connection method between the first assembly member 521 and the second assembly member 522 includes but is not limited to a threaded connection.

[0088] It is understandable that one end of the support arm 512 is connected to the main body 511, and the other end extends axially, so that the third mounting member 510 forms a U-shaped opening to accommodate the tensioning assembly 520 and facilitate the tensioning operation of the target 200. The first assembly member 521 is installed between the two support arms 512 and is separated from the main body 511, and is used to provide a stable and convenient platform. Through the clamping effect between the first mating surface 5211 and the second mating surface, the pre-tightening force between the second assembly member 522 and the first assembly member 521 is adjusted to achieve tensioning of the target 200, reduce imaging errors caused by the uneven surface of the target 200, and thus improve calibration accuracy.

[0089] In some embodiments, Figure 4 As shown, the first mating surface 5211 and the second mating surface are both inclined from a direction away from the main body 511 to a direction close to the guide roller 900 .

[0090] It can be understood that the first mating surface 5211 and the second mating surface are arranged at an angle so that the target 200 is subjected to an inward clamping force when clamped, thereby ensuring that it remains stable during the calibration process and reducing the possibility of loosening or displacement of the target 200 due to vibration or external force.

[0091] In some embodiments, Figure 5As shown, the target 200 includes a line pair target 210, and the imaging area 201 of the line pair target 210 has a geometric figure combination image, so as to adjust the distance and angle of the camera 820 relative to the target 200 during calibration. It should be noted that the number and specific distribution of conventional geometric images can be designed according to actual needs, and this embodiment does not impose specific restrictions on this. Exemplarily, multiple geometric figure combination images are distributed at intervals along the axial direction.

[0092] In some embodiments, Figure 5 As shown, the geometric figure combined image includes two symmetrically arranged sub-images, and the sub-images include two triangles 211, a plurality of first lines and a second line 213 that are symmetrically arranged along the axis, and the plurality of first lines are located between the triangles 211 and the second line 213 along the axis. That is, the two sub-images are symmetrically arranged along the width direction of the line pair target 210, and the triangles 211, the first lines and the second lines 213 are used to provide rich and uniform feature points for the camera 820 calibration, thereby improving the robustness of the calibration process, and the stability and accuracy of the calibration results. Exemplarily, the triangle 211 is a right triangle.

[0093] In some embodiments, Figure 5 As shown, the first line includes two sub-segments 2121 spaced apart along the width direction of the line to the target 210, wherein the length of one sub-segment 2121 along the width direction of the line to the target 210 gradually increases toward the second line 213, and the length of the other sub-segment 2121 along the width direction of the line to the target 210 gradually decreases toward the second line 213.

[0094] It can be understood that the increasing and decreasing sub-segments 2121 provide unique geometric features for the line pair target 210, increase the redundancy of the feature points, thereby improving the fault tolerance of the calibration process and better adapting to different environmental conditions, such as lighting changes, reflection interference or background clutter, thereby improving the recognition effect and reducing the complexity and calculation time of feature extraction during the calibration process.

[0095] In some embodiments, Figure 5 As shown, the target 200 also includes a distortion target 220, and the imaging area 201 of the distortion target 220 has multiple line images 221, that is, by comparing the line width of each line in the line image 221 in the actual image with the line width of each line in the line image 221 in the calibration image, the distortion coefficient of the camera 820 is adjusted during calibration.

[0096] In some embodiments, Figure 5As shown, the target 200 also includes a white balance target 230. The imaging area 201 of the white balance target 230 has a pure color block image, that is, by comparing the image grayscale value in the actual image with the image grayscale value in the calibration image, the camera 820 is normally corrected during calibration. Exemplarily, the color of the pure color block image is white.

[0097] It should be noted that after the posture of the light source 810 is calibrated, the line pair target 210, the distortion target 220 and the white balance target 230 can be relatively fixedly arranged on the guide roller 900 through the second mounting structure 500 to achieve calibration of the posture and parameters of the camera 820.

[0098] An embodiment of the present application also provides a calibration method using the above-mentioned calibration device for roller surface imaging.

[0099] like Figure 6 As shown, the calibration method includes step 710 and step 720.

[0100] Step 710 , the calibration tool 100 and the light source 810 are relatively fixed and the calibration tool 100 clamps the guide roller 900 , and the measured value of the inclinometer is equal to the target value.

[0101] In actual implementation, the two clamping arms 121 of the calibration tool 100 are engaged with the roller surface of the guide roller 900, and the guide roller 900 is rotated so that the angle between the calibration surface 111 and the horizontal plane measured by the inclinometer is equal to the target value, thereby completing the calibration of the posture of the light source 810.

[0102] It should be noted that the light source 810 can be relatively fixedly installed on the calibration fixture 100 through the first installation structure, and then the clamping arm 121 is stopped and matched with the roller surface of the guide roller 900. Alternatively, after the guide roller 900 is rotated so that the measured value of the inclinometer is equal to the target value, the light source 810 can be relatively fixedly installed on the calibration fixture 100, and this embodiment does not impose specific restrictions on this.

[0103] Step 720 , maintaining the calibration fixture 100 and the guide roller 900 , and adjusting the position and posture of the camera 820 based on the imaging area 201 of the target 200 .

[0104] In actual implementation, the states of the guide roller 900 and the target 200 are kept unchanged, and the posture of the camera 820 is adjusted accordingly by comparing the actual image with the calibrated image of the imaging area 201 according to the current position of the imaging area 201 of the target 200.

[0105] It should be noted that the target 200 can be relatively fixedly installed on the connecting member 110 through the third mounting member 510 after the posture of the light source 810 is calibrated; it can also be relatively fixedly installed on the connecting member 110 before the clamping arm 121 of the calibration tooling 100 is stopped and engaged with the roller surface. This embodiment does not impose specific restrictions on this.

[0106] According to the calibration method provided in the embodiment of the present application, through steps 710 and 720, in combination with the above-mentioned calibration device for roller surface imaging, relevant operators can operate according to standard calibration process steps, thereby reducing the blindness of on-site installation and adjustment, thereby reducing the impact of human factors on imaging quality.

[0107] In some embodiments, in some embodiments, step 720 includes:

[0108] The pitch angle, yaw angle, and roll angle of the camera 820 are adjusted respectively until the actual image coincides with the calibration image.

[0109] It can be understood that adjusting the pitch angle of camera 820 is to adjust the imaging angle of camera 820 by tilting the camera 820 up and down; moving the camera 820 horizontally is to adjust the spatial position of camera 820; adjusting the yaw angle of camera 820 is to adjust the imaging angle of camera 820 by tilting the camera 820 left and right; adjusting the roll angle of camera 820 is to adjust the imaging angle of camera 820 by tilting the camera 820 back and forth.

[0110] In this way, through the design of the above scheme, the spatial position and posture of the camera 820 are adjusted, and the imaging area 201 calibrated by the target 200 is cooperated with to solve the problem of the imaging angle being unable to be determined in roller surface imaging, thereby improving the positioning accuracy of the camera 820, and greatly reducing the errors caused by human factors, thereby improving the quality of defect detection of subsequent products.

[0111] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0112] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0113] In the description of this application, "first feature" or "second feature" may include one or more of the features.

[0114] In the description of the present application, “plurality” means two or more.

[0115] In the description of the present application, a first feature being “on” or “under” a second feature may include that the first and second features are directly in contact with each other, or may include that the first and second features are not in direct contact with each other but are in contact with each other via another feature therebetween.

[0116] In the description of the present application, “above”, “over” and “above” a first feature to a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0117] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0118] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A calibration device for roller surface imaging, characterized in that: include: A calibration tool (100), the calibration tool (100) being a symmetrical structure, the calibration tool (100) comprising a connecting piece (110) and a clamping piece connected to each other, the connecting piece (110) having a calibration surface (111) and being used to install a light source (810), the calibration surface (111) being perpendicularly intersected with a symmetry plane of the calibration tool (100), and the clamping piece being used to clamp a guide roller (900); An inclinometer, used for measuring the inclination angle of the calibration surface (111); A target (200) is arranged on the connecting member (110), the length of the target (200) extends along the axial direction of the guide roller (900), and is used for contacting and cooperating with the guide roller (900), and the target (200) has an imaging area (201), and the imaging area (201) is mirror-symmetrical with respect to the symmetry plane.

2. The calibration device for roller surface imaging according to claim 1, characterized in that: The clamping member comprises two clamping arms (121) respectively arranged at two ends of the connecting member (110), and the two clamping arms (121) both have clamping surfaces that are mirror-symmetrical with respect to the symmetry plane, and the clamping surfaces are used to cooperate with the roller surface of the guide roller (900); wherein, The clamping surface is a plane, and the distance between the two clamping surfaces gradually increases in a direction away from the connecting member (110); or The clamping surface is a curved surface, and the center of curvature of the clamping surface is located inside the guide roller (900).

3. The calibration device for roller surface imaging according to claim 1, characterized in that: The connecting member (110) is provided with a detachable first mounting structure for fixing the light source (810).

4. The calibration device for roller surface imaging according to claim 3, characterized in that: The first mounting structure comprises: A first mounting member (310), the first mounting member (310) being protruding from the calibration surface (111); The second mounting member (320) is used to mount the light source (810); the second mounting member (320) is mounted on the first mounting member (310) in an angle-adjustable manner; the rotation axis of the second mounting member (320) is parallel to the axial direction and is located within the symmetry plane.

5. The calibration device for roller surface imaging according to claim 4, characterized in that: The second mounting member (320) comprises: A first section (321), wherein one end of the first section (321) is mounted on the first mounting member (310) in an angle-adjustable manner; The second section (322) is arranged at the other end of the first section (321), and the extension direction of the first section (321), the extension direction of the second section (322) and the axial direction are perpendicular to each other.

6. The calibration device for roller surface imaging according to claim 5, characterized in that: The second section (322) is provided with an adjusting member (400) for adjusting the installation position of the light source (810).

7. The calibration device for roller surface imaging according to claim 1, characterized in that: The connecting member (110) is provided with a detachable second mounting structure (500) for fixing the target (200).

8. The calibration device for roller surface imaging according to claim 7, characterized in that: The second mounting structure (500) comprises: A third mounting member (510) is arranged on the connecting member (110); A tensioning assembly (520) is disposed on the third mounting member (510) and is used to tension the target (200).

9. The calibration device for roller surface imaging according to claim 8, characterized in that: The third mounting member (510) comprises a main body (511) and two supporting arms (512) arranged opposite to each other, one end of each supporting arm (512) being connected to the main body (511) and extending along the axial direction; the tensioning assembly (520) comprises: A first assembly part (521), installed between the two supporting arms (512) and spaced apart from the main body (511), and the first assembly part (521) has a first mating surface (5211); The second assembly part (522) is mounted on the first assembly part (521) and has a second mating surface, and the end portion of the target (200) is located between the first mating surface (5211) and the second mating surface.

10. The calibration device for roller surface imaging according to claim 9, characterized in that: The first mating surface (5211) and the second mating surface are both inclined in a direction away from the main body (511) and toward a direction close to the guide roller (900).

11. The calibration device for roller surface imaging according to any one of claims 1 to 10, characterized in that: The target (200) includes a line pair target (210), wherein an imaging area (201) of the line pair target (210) has a geometrically combined image, wherein the geometrically combined image includes two symmetrically arranged sub-images, wherein the sub-images include two triangles (211) symmetrically arranged along an axial direction, a plurality of first lines and a second line (213), wherein the plurality of first lines are axially located between the triangles (211) and the second lines (213).

12. The calibration device for roller surface imaging according to claim 11, characterized in that: The first line comprises two sub-segments (2121) spaced apart along the width direction of the line pair target (210), wherein the length of one of the sub-segments (2121) along the width direction of the line pair target (210) gradually increases in a direction approaching the second line (213), and the length of the other sub-segment (2121) along the width direction of the line pair target (210) gradually decreases in a direction approaching the second line (213).

13. A calibration method using the calibration device for roller surface imaging according to any one of claims 1 to 12, characterized in that: include: The calibration tool (100) and the light source (810) are relatively fixed and the calibration tool (100) clamps the guide roller (900), and the measured value of the angle meter is equal to the target value; The calibration tool (100) and the guide roller (900) are maintained, and the position and posture of the camera (820) are adjusted based on the imaging area (201) of the target (200).

Images