Coating system and calibration method thereof

Abstract

A coating system and a calibration method thereof. The coating system comprises: a guide roller (110), a line scan camera (120), an encoder (130), a controller (150), and a calibration ruler. The guide roller (110) comprises a first guide roller (111) and a second guide roller (112). The calibration ruler is disposed on the guide roller (110) and comprises a plurality of staggered calibration blocks. The encoder (130) is mounted coaxially with the guide roller (110) or is in contact with the guide roller (110) by means of a support-mounted press roller, and generates a first trigger signal; one or more line scan cameras (120) are disposed on one side of the guide roller (110), and the photographing field of view of the camera corresponds to the calibration ruler. Upon receipt of the first trigger signal or under the trigger of a second trigger signal in the line scan camera (120), the line scan camera (120) photographs the calibration ruler to obtain an image. The controller (150) calculates at least one of lateral precision and longitudinal precision of the line scan camera (120) on the basis of the image. The system improves the precision and accuracy of camera calibration.

Description

Coating system and calibration method thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202311646481.9, filed on December 1, 2023, entitled “Coating system and calibration method thereof,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the technical field of quality inspection of battery pole pieces, and in particular to a coating system and a calibration method thereof. Background Art

[0004] In wide-format coating visual inspection systems, both the A and B sides of the electrode need to be inspected. Due to the large width of the electrode, high inspection accuracy is required for the A side of the electrode, so dual cameras are required to take photos and stitch the images together before inspection. The same applies to the B side. In image measurement and machine vision applications, camera calibration is required to determine the relationship between the three-dimensional geometric position of a point on the surface of a spatial object and its corresponding point in the image. Related technologies suffer from poor accuracy in debugging cameras and camera calibration, which impacts the overall equipment acceptance process.

[0005] Summary of the Invention

[0006] A technical problem solved by the present application is that, in the related art, the calibration accuracy of the camera of the coating system is relatively poor.

[0007] According to one aspect of the present application, a coating system is provided, comprising: a first roller and a second roller; a calibration ruler, arranged on the first roller or the second roller, comprising a plurality of calibration blocks arranged in an staggered manner; an encoder, mounted coaxially with the first roller or the second roller, or mounted on a bracket and in contact with the first roller or the second roller by a pressure wheel mounting method, and configured to generate a first trigger signal under the drive of the first roller or the second roller; one or more line scan cameras, arranged on one side of the first roller or the second roller, wherein the photographing field of the one or more line scan cameras corresponds to the calibration ruler, and the line scan camera is configured to photograph the calibration ruler to obtain an image after receiving the first trigger signal or when triggered by a second trigger signal inside the line scan camera; and a controller for calculating at least one of the lateral accuracy and longitudinal accuracy of the line scan camera based on the image.

[0008] In the technical solution of the embodiment of the present application, a calibration ruler is set on the roller, and the encoder generates a first trigger signal driven by the roller. The photographing field of the line scan camera corresponds to the calibration ruler. The line scan camera photographs the calibration ruler under the triggering of the first trigger signal or the second trigger signal to obtain an image. The controller calculates at least one of the lateral accuracy and the longitudinal accuracy based on the image, thereby improving the calibration accuracy of the camera of the coating system.

[0009] In some embodiments, the coating system further includes: an acquisition card electrically connected to the encoder and to one or more line scan cameras, configured to receive the first trigger signal from the encoder, send the first trigger signal to the one or more line scan cameras, receive images captured by the one or more line scan cameras, and send the images to the controller. In this embodiment, the acquisition card facilitates image acquisition.

[0010] In some embodiments, the calibration ruler includes: a plurality of first calibration blocks spaced apart in a first row and a plurality of second calibration blocks spaced apart in a second row, the plurality of first calibration blocks and the plurality of second calibration blocks being arranged in an alternating pattern, with the first portion of each first calibration block and the second portion of each second calibration block being aligned in a straight line; the calibration ruler is aligned with the first roller along a positioning line on the first roller, or aligned with the second roller along a positioning line on the second roller; the line scan camera photographs the calibration ruler to obtain a first image when triggered by the second trigger signal, and photographs the calibration ruler to obtain a second image after receiving the first trigger signal. In this embodiment, by providing two rows of alternating calibration blocks, it is facilitated for the camera to capture corresponding images, thereby achieving camera accuracy calibration.

[0011] In some embodiments, the calibration ruler further includes a third calibration block located in a row different from the first row and the second row. In this embodiment, the third calibration block is provided to facilitate confirmation of the overlapping fields of view of the two cameras based on the third calibration block.

[0012] In some embodiments, the third calibration block is aligned with one of the plurality of second calibration blocks in a direction perpendicular to the direction in which the second row extends. In this embodiment, aligning the third calibration block with one of the second calibration blocks facilitates determining the overlapping fields of view of the two cameras based on the third calibration block.

[0013] In some embodiments, the controller is configured to calculate the lateral accuracy based on a first image captured by the one or more line scan cameras in response to the second trigger signal, wherein the first image includes the first portion and the second portion alternating along the same straight line. In this embodiment, the first image is captured using in-camera triggering, thereby facilitating calculation of the camera's lateral calibration accuracy.

[0014] In some embodiments, the controller is configured to calculate the longitudinal accuracy based on a second image captured by the one or more line scan cameras after receiving the first trigger signal, wherein the second image includes the plurality of first calibration blocks and the plurality of second calibration blocks. In this embodiment, the line scan cameras are triggered by an encoder to capture the second image, thereby facilitating the calculation of the longitudinal calibration accuracy of the cameras.

[0015] In some embodiments, the one or more line scan cameras include a plurality of line scan cameras, wherein the plurality of line scan cameras are arranged side by side, the imaging points of the plurality of line scan cameras are collinear, and the imaging field of view of each of the plurality of line scan cameras corresponds to a portion of the calibration scale; the controller is configured to determine the overlapping fields of view of the plurality of line scan cameras when all of the plurality of line scan cameras capture images containing the third calibration block. In this embodiment, the overlapping fields of view of the plurality of line scan cameras are determined, thereby facilitating the removal of overlapping fields of view during precision calibration and improving camera calibration accuracy.

[0016] In some embodiments, each of the plurality of line scan cameras is configured to capture a first image when triggered by the second trigger signal, thereby enabling the plurality of line scan cameras to obtain a plurality of first images; the controller is configured to remove overlapping portions of the plurality of first images based on the overlapping fields of view of the plurality of line scan cameras, stitch the plurality of first images after removing the overlapping portions into a third image, and calculate the lateral accuracy based on the third image. In this embodiment, by removing overlapping portions of the plurality of first images to stitch them into the third image, and then calculating the lateral accuracy of the camera based on the third image, the lateral calibration accuracy of the camera is improved.

[0017] In some embodiments, the controller is configured to calculate the lateral accuracy corresponding to the area between two adjacent edges in the first and second portions that are alternately arranged on the same straight line based on the lateral length of the area between the two adjacent edges and the lateral pixel positions of the two adjacent edges. This enables calculation of the camera's lateral accuracy and improves the camera's lateral calibration accuracy.

[0018] In some embodiments, each of the multiple line scan cameras is configured to capture a second image upon receiving the first trigger signal, thereby enabling the multiple line scan cameras to obtain multiple second images. The controller is configured to remove overlapping portions of the multiple second images based on the overlapping fields of view of the multiple line scan cameras, stitch the multiple second images after removing the overlapping portions into a fourth image, and calculate the longitudinal accuracy based on the fourth image. In this embodiment, by removing overlapping portions of the multiple second images, stitching them into a fourth image, and then calculating the longitudinal accuracy based on the fourth image, the longitudinal calibration accuracy of the camera is improved.

[0019] In some embodiments, the controller is configured to calculate the longitudinal accuracy corresponding to the area between the two edges based on the longitudinal length of the first calibration block or the second calibration block between the two edges of the first portion and the second portion alternately arranged on the same straight line, and the longitudinal pixel position of the lower edge and the longitudinal pixel position of the upper edge of the first calibration block or the second calibration block between the two edges. This enables calculation of the longitudinal accuracy of the camera, thereby improving the longitudinal calibration accuracy of the camera.

[0020] According to another aspect of the present application, a calibration method for a coating system is provided, the coating system comprising: a first roller and a second roller; a calibration ruler, arranged on the first roller or the second roller, comprising a plurality of calibration blocks arranged in an staggered manner; an encoder, mounted coaxially with the first roller or the second roller, or mounted on a bracket and in contact with the first roller or the second roller by a pressure wheel mounting method; one or more line scan cameras, arranged on one side of the first roller or the second roller, wherein the photographing field of the one or more line scan cameras corresponds to the calibration ruler; and a controller; the calibration method comprising: the encoder generating a first trigger signal driven by the first roller or the second roller; the line scan camera photographing the calibration ruler to obtain an image after receiving the first trigger signal or when triggered by a second trigger signal inside the line scan camera; and the controller calculating at least one of the lateral accuracy and longitudinal accuracy of the line scan camera based on the image.

[0021] In the technical solution of the embodiment of the present application, the encoder generates a first trigger signal driven by the roller, the line scan camera takes a picture of the calibration ruler under the triggering of the first trigger signal or the second trigger signal to obtain an image, and the controller calculates at least one of the lateral accuracy and the longitudinal accuracy based on the image, thereby improving the calibration accuracy of the camera of the coating system.

[0022] In some embodiments, a calibration ruler includes: a plurality of first calibration blocks spaced apart in a first row and a plurality of second calibration blocks spaced apart in a second row, the plurality of first calibration blocks and the plurality of second calibration blocks being arranged in an alternating pattern, with the first portion of each first calibration block and the second portion of each second calibration block being aligned on the same line; the calibration ruler is aligned with the first roller along a positioning line on the first roller, or aligned with the second roller along a positioning line on the second roller; a line scan camera photographs the calibration ruler to obtain an image upon receiving a first trigger signal or triggered by a second trigger signal within the line scan camera, including: the line scan camera photographs the calibration ruler to obtain a first image upon triggering by the second trigger signal; and a controller calculates at least one of a lateral accuracy and a longitudinal accuracy of the line scan camera based on the image, including: the controller calculates the lateral accuracy based on the first image when one or more line scan cameras are triggered by the second trigger signal to obtain the first image, wherein the first image includes first and second portions alternating on the same line. In this embodiment, the first image is captured by in-camera triggering, thereby facilitating calculation of the camera's lateral calibration accuracy.

[0023] In some embodiments, after receiving a first trigger signal or triggered by a second trigger signal within the line scan camera, the line scan camera photographs the calibration ruler to obtain an image, including: the line scan camera photographs the calibration ruler to obtain a second image after receiving the first trigger signal; and the controller calculates at least one of the lateral accuracy and longitudinal accuracy of the line scan camera based on the image, including: when one or more line scan cameras photograph and obtain the second image after receiving the first trigger signal, the controller calculates the longitudinal accuracy based on the second image, wherein the second image includes multiple first calibration blocks and multiple second calibration blocks. In this embodiment, the line scan camera is triggered by an encoder to capture the second image, thereby facilitating the calculation of the camera's longitudinal calibration accuracy.

[0024] In some embodiments, the calibration ruler further includes: a third calibration block in a row different from the first and second rows; the one or more line scan cameras include multiple line scan cameras, wherein the multiple line scan cameras are arranged side by side, the photographing points of the multiple line scan cameras are collinear, and the photographing field of view of each of the multiple line scan cameras corresponds to a portion of the calibration ruler; the calibration method further includes: the controller determining the overlapping fields of view of the multiple line scan cameras when all the multiple line scan cameras photograph and obtain an image containing the third calibration block. In this embodiment, the overlapping fields of view of the multiple line scan cameras are determined, thereby facilitating the removal of overlapping fields of view during precision calibration and improving camera calibration accuracy.

[0025] In some embodiments, the line scan camera photographs the calibration ruler to obtain a first image when triggered by a second trigger signal, including: each of the plurality of line scan cameras photographs the calibration ruler to obtain a first image when triggered by the second trigger signal, thereby allowing the plurality of line scan cameras to obtain a plurality of first images; and when one or more line scan cameras photograph the calibration ruler to obtain a first image when triggered by the second trigger signal, the controller calculates the lateral accuracy based on the first image, including: the controller removes overlapping portions of the plurality of first images based on overlapping fields of view of the plurality of line scan cameras, splices the plurality of first images after removing the overlapping portions into a third image, and calculates the lateral accuracy based on the third image. In this embodiment, by removing overlapping portions of the plurality of first images to splice the images into the third image, and calculating the lateral accuracy of the camera based on the third image, the lateral calibration accuracy of the camera is improved.

[0026] In some embodiments, the controller calculating the lateral accuracy based on the third image includes: the controller calculating the lateral accuracy corresponding to the area between two adjacent edges in the first portion and the second portion that are alternately arranged on the same straight line based on the lateral length of the area between the two adjacent edges and the lateral pixel positions of the two adjacent edges. This enables calculation of the lateral accuracy of the camera and improves the lateral calibration accuracy of the camera.

[0027] In some embodiments, after receiving a first trigger signal, a line scan camera photographs the calibration ruler to obtain a second image, including: each of the plurality of line scan cameras photographs and obtains a second image after receiving the first trigger signal, thereby allowing the plurality of line scan cameras to obtain a plurality of second images; and when one or more line scan cameras photograph and obtain a second image after receiving the first trigger signal, a controller calculates longitudinal accuracy based on the second image, including: the controller removes overlapping portions of the plurality of second images based on the overlapping fields of view of the plurality of line scan cameras, splices the plurality of second images after removing the overlapping portions into a fourth image, and calculates the longitudinal accuracy based on the fourth image. In this embodiment, by removing overlapping portions of the plurality of second images and splicing them into a fourth image, and then calculating the longitudinal accuracy based on the fourth image, the longitudinal calibration accuracy of the camera is improved.

[0028] In some embodiments, the controller calculating the longitudinal accuracy based on the fourth image includes: the controller calculating the longitudinal accuracy corresponding to the area between two edges based on the longitudinal length of the first calibration block or the second calibration block between two edges of the first portion and the second portion alternately arranged on the same straight line, and the longitudinal pixel position of the lower edge and the longitudinal pixel position of the upper edge of the first calibration block or the second calibration block between the two edges. This implements the calculation of the longitudinal accuracy of the camera and improves the longitudinal calibration accuracy of the camera. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0030] FIG1 is a schematic structural diagram illustrating a coating system according to some embodiments of the present application;

[0031] FIG2 is a schematic structural diagram illustrating a coating system according to some embodiments of the present application;

[0032] FIG3 is a block diagram schematically illustrating a coating system according to some embodiments of the present application;

[0033] FIG4 is a block diagram schematically illustrating a coating system according to other embodiments of the present application;

[0034] FIG5 is a schematic diagram showing a roller according to some embodiments of the present application;

[0035] FIG6 is a schematic diagram illustrating photographing by a line scan camera according to some embodiments of the present application;

[0036] 7 is a flow chart illustrating a method for calibrating a coating system according to some embodiments of the present application;

[0037] FIG8 is a flow chart illustrating a method for calibrating a coating system according to other embodiments of the present application;

[0038] FIG9 is a schematic diagram showing a calibration ruler according to some embodiments of the present application;

[0039] FIG10 is a schematic diagram showing a partial structure of a calibration ruler according to some embodiments of the present application;

[0040] FIG11 is a schematic diagram showing an image obtained by taking a picture with a line scan camera according to some embodiments of the present application;

[0041] FIG12 is a schematic diagram showing images obtained by taking pictures with a line scan camera according to other embodiments of the present application;

[0042] FIG13 is a schematic diagram showing stitched images of a calibration ruler taken according to some embodiments of the present application;

[0043] FIG14 is a schematic diagram showing stitched images of photographed calibration rulers according to other embodiments of the present application;

[0044] FIG15 is a schematic diagram showing a stitched black and white image of a calibration ruler photographed according to some embodiments of the present application;

[0045] FIG16 is a schematic diagram showing stitched images of photographed calibration rulers according to other embodiments of the present application;

[0046] FIG17 is a schematic diagram illustrating how to obtain pole piece dimensions according to some embodiments of the present application. DETAILED DESCRIPTION

[0047] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the present application and its application or use. The present application can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present application thorough and complete and to fully convey the scope of the present application to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions, and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary, rather than as limiting.

[0048] The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Terms such as "include" or "comprises" mean that the elements preceding the term encompass the elements listed after the term, and do not exclude the possibility of also encompassing other elements. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0049] In this application, when a specific device is described as being located between a first device and a second device, an intervening device may or may not be present between the specific device and the first device or the second device. When a specific device is described as being connected to another device, the specific device may be directly connected to the other device without an intervening device, or may be not directly connected to the other device but with an intervening device.

[0050] All terms (including technical or scientific terms) used in this application have the same meaning as those understood by ordinary technicians in the field to which this application belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or highly formal sense, unless explicitly defined herein.

[0051] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0052] In the related art, the calibration of cameras and cameras is time-consuming and has poor accuracy, which affects the overall acceptance progress of the equipment. The inventors of this application analyzed and found that the main reasons are as follows: (1) The camera calibration method used on site requires the actual size information of the pole piece produced by the main equipment, so it is necessary to wait until actual production to calibrate. The camera calibration progress is affected by the progress of the main equipment, and the dimensions required for calibration are the film width and pole width measured manually. This method has measurement errors, resulting in low calibration accuracy; (2) When the main equipment is cut and pulled, the size information of the new variety needs to be re-measured for re-calibration, which also wastes manpower and material resources; (3) In the absence of pole pieces, when the encoder is not installed on the photo roller, the encoder cannot directly trigger the camera to take pictures, resulting in the inability to calibrate the longitudinal accuracy of the camera. In addition, there is a situation where the encoder slips or the pole piece and the roller slip, which makes the longitudinal progress calculation wrong, and then makes the longitudinal size calculation of the film wrong.

[0053] In view of this, an embodiment of the present application provides a coating system to improve the calibration accuracy of a camera.

[0054] Figure 1 is a schematic diagram illustrating a coating system according to some embodiments of the present application. Figure 2 is a schematic diagram illustrating a coating system according to some embodiments of the present application. Figure 3 is a block diagram schematically illustrating a coating system according to some embodiments of the present application.

[0055] As shown in FIG1 , the coating system includes a roller 110. The roller 110 is disposed on a support 101. The roller 110 includes a first roller 111 and a second roller 112. For example, the first roller 111 and the second roller 112 are disposed in parallel on the support. For example, the first roller 111 can serve as a photo roller (i.e., a roller for being photographed by a camera), and the second roller 112 can also serve as a photo roller.

[0056] The coating system also includes a calibration ruler. For example, the calibration ruler can be a calibration ruler as shown in Figure 9. The calibration ruler is set on the roller. For example, the calibration ruler is set on the first roller 111 or the second roller 112. Figure 5 is a schematic diagram of the roller according to some embodiments of the present application. For example, as shown in Figure 5, a positioning line 201 parallel to the first roller can be set on the surface of the first roller (for example, the photo roller) 111. For example, the positioning line 201 can be silk-screened on the surface of the first roller 111. The positioning line is parallel to the roller axis of the first roller. In this way, when the calibration ruler is affixed to the roller, the calibration ruler can be attached parallel to the roller. For example, the calibration ruler is shown in Figure 9. When affixing the calibration ruler, the upper edge of the calibration ruler is attached to the surface of the first roller along the positioning line. As shown in Figure 9, the calibration ruler includes a plurality of calibration blocks arranged in an interlaced manner.

[0057] For example, the calibration ruler is made of soft film with a white background, and its accuracy can be 0.005mm.

[0058] As shown in Figures 1 to 3, the coating system also includes an encoder 130. For example, as shown in Figure 1, the encoder 130 is coaxially mounted with the first roller 111 or the second roller 112, or is mounted on the bracket 101 and contacts the first roller 111 or the second roller 112 in a pressure wheel mounting manner (i.e., the encoder pressure wheel is pressed on the photographing roller). The encoder 130 is configured to generate a first trigger signal driven by the first roller or the second roller. When the rollers rotate, the encoder can rotate synchronously. In this way, the encoder 130 can generate a first trigger signal driven by the first roller 111 or the second roller 112. The first trigger signal is used to trigger a line scan camera (described later) to take a picture of the calibration scale.

[0059] As shown in Figures 1 to 3, the coating system also includes one or more line scan cameras 120. The one or more line scan cameras 120 are electrically connected to the encoder 130. The one or more line scan cameras 120 are arranged on one side of the first roller 111 or the second roller 112. The photographing field of the one or more line scan cameras corresponds to the calibration ruler. The line scan camera is configured to take a picture of the calibration ruler to obtain an image after receiving a first trigger signal or when triggered by a second trigger signal inside the line scan camera. Here, the second trigger signal is a trigger signal sent by the clock inside the line scan camera at predetermined intervals when the line scan camera is in internal trigger mode, so as to trigger the line scan camera to take pictures at the predetermined intervals.

[0060] For example, as shown in FIG1 , the one or more line scan cameras 120 include multiple line scan cameras. For example, the multiple line scan cameras include a first line scan camera 121 and a second line scan camera 122 . The first line scan camera 121 and the second line scan camera 122 can be arranged side by side on the bracket 101 , with the imaging fields of the first line scan camera 121 and the second line scan camera 122 corresponding to the calibration scale provided on the first roller 111 . This facilitates the use of the first line scan camera 121 and the second line scan camera 122 to capture images of the calibration scale on the first roller 111 . Furthermore, as shown in FIG2 , if a pole piece is present in the coating system, the first line scan camera 121 and the second line scan camera 122 can also be configured to image the first surface 141 of the pole piece 140 .

[0061] For another example, as shown in Figure 1 or 2 , the multiple line scan cameras may further include a third line scan camera 123 and a fourth line scan camera 124. The third line scan camera 123 and the fourth line scan camera 124 may be arranged side by side on the bracket 101, with the imaging fields of the third line scan camera 123 and the fourth line scan camera 124 corresponding to the calibration scale provided on the second roller 112. This facilitates the use of the third line scan camera 123 and the fourth line scan camera 124 to capture images of the calibration scale on the second roller 112. Furthermore, as shown in Figure 2 , if a pole piece is present in the coating system, the third line scan camera 123 and the fourth line scan camera 124 are further configured to image the second surface 142 of the pole piece 140.

[0062] As shown in FIG3 , the coating system further includes a controller 150. The controller 150 is electrically connected to the one or more line scan cameras 120. For example, as shown in FIG3 , the controller 150 is electrically connected to the first line scan camera 121 and the second line scan camera 122. For another example, the controller 150 may also be electrically connected to the third line scan camera 123 and the fourth line scan camera 124. The controller 150 is configured to calculate at least one of the lateral accuracy and the longitudinal accuracy of the line scan cameras based on the images.

[0063] Here, the lateral accuracy refers to the actual lateral length represented by the lateral length of each pixel in the image captured by the line scan camera; the longitudinal accuracy refers to the actual longitudinal length represented by the longitudinal length of each pixel in the image captured by the line scan camera.

[0064] Thus, a coating system according to some embodiments of the present application is provided. The coating system includes: a first roller and a second roller; a calibration ruler disposed on the first roller or the second roller, comprising a plurality of calibration blocks arranged in an interlaced manner; an encoder coaxially mounted with the first roller or the second roller, or mounted on a bracket and contacting the first roller or the second roller using a pressure wheel mounting method, and configured to generate a first trigger signal when driven by the first roller or the second roller; one or more line scan cameras disposed on one side of the first roller or the second roller, wherein the photographing field of the one or more line scan cameras corresponds to the calibration ruler, and the line scan cameras are configured to photograph the calibration ruler to obtain an image after receiving the first trigger signal or when triggered by a second trigger signal within the line scan camera; and a controller for calculating at least one of the lateral accuracy and longitudinal accuracy of the line scan camera based on the image. In this embodiment, a calibration ruler is provided on the roller, and the encoder generates a first trigger signal driven by the roller. The photographing field of the line scan camera corresponds to the calibration ruler. The line scan camera photographs the calibration ruler under the triggering of the first trigger signal or the second trigger signal to obtain an image. The controller calculates at least one of the lateral accuracy and longitudinal accuracy of the line scan camera based on the image, thereby improving the calibration accuracy of the camera of the coating system.

[0065] This high-precision calibration ruler, suitable for wide-format coating, allows camera calibration to be performed independently without waiting for the main equipment to start production. Furthermore, the coating system improves upon the mechanical structure of related technologies by providing a mechanism that links the encoder to the roller, allowing longitudinal camera calibration to be performed independently of pole piece movement.

[0066] FIG4 is a block diagram schematically illustrating a coating system according to other embodiments of the present application.

[0067] As shown in Figure 4, the coating system includes an encoder 130, one or more line scan cameras 120 (eg, a first line scan camera 121 and a second line scan camera 122), and a controller 150. Of course, as mentioned above, the coating system also includes a roller 110 and a calibration ruler.

[0068] In some embodiments, as shown in FIG4 , the coating system further includes an acquisition card 160. The acquisition card 160 is electrically connected to the encoder 130 and to one or more line scan cameras 120. The acquisition card 160 is configured to receive a first trigger signal from the encoder 130, transmit the first trigger signal to the one or more line scan cameras 120, receive images captured by the one or more line scan cameras, and transmit the images to the controller 150. For example, the acquisition card 160 transmits the first trigger signal to the first line scan camera 121 and the second line scan camera 122, receives images captured by the first line scan camera 121 and the second line scan camera 122, and transmits the images to the controller 150. In this embodiment, the acquisition card facilitates image capture.

[0069] FIG10 is a schematic diagram showing a partial structure of a calibration ruler according to some embodiments of the present application. The calibration ruler will be described in detail below in conjunction with FIG9 and FIG10.

[0070] As shown in Figures 9 and 10, the calibration ruler includes a plurality of first calibration blocks 510 spaced apart in a first row and a plurality of second calibration blocks 520 spaced apart in a second row. The plurality of first calibration blocks 510 and the plurality of second calibration blocks 520 are arranged in a staggered manner. The first portion 511 of each first calibration block 510 and the second portion 522 of each second calibration block 520 are arranged on the same straight line 540.

[0071] As previously described, the calibration ruler is aligned with the roller along the positioning line on the roller. For example, the calibration ruler is aligned with the first roller along the positioning line on the first roller, or aligned with the second roller along the positioning line on the second roller. In some embodiments, the line scan camera photographs the calibration ruler in response to a second trigger signal to obtain a first image, and photographs the calibration ruler again after receiving the first trigger signal to obtain a second image.

[0072] In the above embodiment, two rows of staggered calibration blocks are provided to facilitate the camera to capture corresponding images, so as to achieve calibration of camera accuracy.

[0073] In some embodiments, the dimensions of the first calibration block 510 are the same as the dimensions of the second calibration block 520. For example, the length h2 of the first calibration block 510 in the direction perpendicular to the extension of the calibration ruler (i.e., the X direction in FIG. 10 ) is 50 mm (millimeter) ± 0.01 mm, that is, the length h2 of the first calibration block 510 is in the range of 49.99 mm ≤ h2 ≤ 50.01 mm. Similarly, the length of the second calibration block 520 in the direction perpendicular to the extension of the calibration ruler can also be 50 mm ± 0.01 mm, that is, the length of the second calibration block 520 is in the range of 49.99 mm ≤ the length of the second calibration block 520 ≤ 50.01 mm. For another example, the width w2 of the second calibration block 520 in the extension direction parallel to the calibration ruler is 15 mm ± 0.01 mm, that is, the range of the width w2 of the second calibration block 520 is 14.99 mm ≤ w2 ≤ 15.01 mm; similarly, the width of the first calibration block 510 in the extension direction parallel to the calibration ruler is 15 mm ± 0.01 mm, that is, the range of the width of the first calibration block 510 is 14.99 mm ≤ the width of the first calibration block 510 ≤ 15.01 mm.

[0074] Of course, those skilled in the art will appreciate that the size of the first calibration block 510 may be different from the size of the second calibration block 520. The scope of the present application is not limited thereto.

[0075] In some embodiments, the first spacing w1 between adjacent first calibration blocks 510 and second calibration blocks 520 is 15 mm ± 0.01 mm, that is, the range of the first spacing w1 is 14.99 mm ≤ w1 ≤ 15.01 mm. Of course, those skilled in the art will understand that the scope of this application is not limited to the specific value of the first spacing w1.

[0076] In some embodiments, the second spacing w6 between two adjacent first calibration blocks 510 is 45 mm ± 0.01 mm, that is, the range of the second spacing w6 is 44.99 mm ≤ w6 ≤ 45.01 mm. Of course, those skilled in the art will understand that the scope of this application is not limited to the specific value of the second spacing w6.

[0077] In some embodiments, the spacing between two adjacent second calibration blocks 520 is equal to the second spacing. Of course, those skilled in the art will appreciate that the spacing between two adjacent second calibration blocks 520 may not be equal to the second spacing.

[0078] In some embodiments, a first dimension w5 of the calibration ruler parallel to the extension direction of the calibration ruler is 1600 mm ± 0.05 mm, that is, the range of the first dimension w5 of the calibration ruler is 1599.95 mm ≤ w6 ≤ 1600.05 mm; a second dimension h4 of the calibration ruler perpendicular to the extension direction of the calibration ruler is 150 mm ± 0.05 mm, that is, the range of the second dimension h4 of the calibration ruler is 149.95 mm ≤ h4 ≤ 150.05 mm. Of course, those skilled in the art will understand that the scope of this application is not limited to the specific values ​​of the first and second dimensions of the calibration ruler.

[0079] In some embodiments, the dimension h1 of the first portion 511 of the first calibration block 510 in a direction perpendicular to the extension direction of the calibration ruler is 2 mm ± 0.01 mm, that is, the range of the dimension h1 is 1.99 mm ≤ h1 ≤ 2.01 mm. Of course, those skilled in the art will understand that the scope of this application is not limited to a specific value of the dimension h1.

[0080] In some embodiments, the dimension of the second portion 522 of the second calibration block 520 in a direction perpendicular to the extension of the calibration ruler is the same as the dimension h1, that is, also 2 mm ± 0.01 mm. Of course, those skilled in the art will understand that the scope of this application is not limited to the specific value of this dimension of the second portion 522.

[0081] In some embodiments, as shown in Figures 9 and 10, the calibration ruler further includes a third calibration block 530. This third calibration block 530 is located in a row different from the first and second rows. For example, the third calibration block 530 is located above the first row of the plurality of first calibration blocks 510. In this embodiment, the provision of the third calibration block facilitates confirmation of the overlapping fields of view of the two cameras based on the third calibration block.

[0082] For example, the dimension w3 of the third calibration block 530 in the direction parallel to the extension of the calibration ruler is 15±0.01 mm, that is, the range of the dimension w3 of the third calibration block 530 is 14.99 mm ≤ w3 ≤ 15.01 mm; the dimension h3 of the third calibration block 530 in the direction perpendicular to the extension of the calibration ruler is 15±0.01 mm, that is, the range of the dimension h3 of the third calibration block 530 is 14.99 mm ≤ h3 ≤ 15.01 mm. Of course, those skilled in the art will understand that the scope of this application is not limited to the specific values ​​of the dimensions w3 and h3.

[0083] For example, the distance h5 between the third calibration block 530 and the first calibration block 510 in the direction perpendicular to the extension of the calibration ruler is 2 mm ± 0.01 mm, that is, the range of the distance h5 is 1.99 mm ≤ h5 ≤ 2.01 mm. Of course, those skilled in the art will understand that the scope of this application is not limited to a specific value of the dimension h5.

[0084] For example, the distance w4 between the third calibration block 530 and one edge of the calibration ruler is 800 mm ± 0.05 mm, that is, the range of the distance w4 is 799.95 mm ≤ w4 ≤ 800.05 mm. Of course, those skilled in the art will understand that the scope of this application is not limited to the specific value of the distance w4.

[0085] In some embodiments, as shown in Figures 9 and 10, third calibration block 530 is aligned with one of the plurality of second calibration blocks 520 in a direction perpendicular to the direction of extension of the second row. In this embodiment, aligning the third calibration block with one of the second calibration blocks facilitates confirming the overlapping fields of view of the two cameras based on the third calibration block.

[0086] In some embodiments, the controller 150 is configured to calculate the lateral calibration accuracy based on a first image captured by one or more line scan cameras in response to a second trigger signal, wherein the first image comprises a first portion and a second portion alternating along the same straight line. For example, the second trigger signal may be an internal camera trigger. For example, the line scan camera, in response to the second trigger signal, captures a first image of the calibration ruler and transmits the first image to the controller, which then calculates the lateral calibration accuracy of the camera based on the first image. In this embodiment, capturing the first image through internal camera triggering facilitates calculation of the camera's lateral calibration accuracy.

[0087] In some embodiments, the controller 150 is configured to calculate the longitudinal accuracy based on a second image obtained by the one or more line scan cameras after receiving a first trigger signal, wherein the second image includes the plurality of first calibration blocks and the plurality of second calibration blocks. For example, the camera triggering mode is changed to encoder triggering, the camera roller is rotated, and the line scan camera, after receiving the first trigger signal from the encoder, takes a picture of the calibration ruler to obtain a second image. The captured second image is saved and sent to the controller, which then calculates the longitudinal calibration accuracy of the camera based on the second image.

[0088] In some embodiments, the one or more line scan cameras 120 include multiple line scan cameras, wherein the multiple line scan cameras are arranged side by side, their capture points are collinear, and the field of view of each of the multiple line scan cameras corresponds to a portion of the calibration scale. For example, as shown in Figures 1 and 6, the multiple line scan cameras 120 include a first line scan camera 121 and a second line scan camera 122. The first line scan camera 121 and the second line scan camera 122 are arranged side by side, their capture points are collinear, and the field of view of the first line scan camera 121 corresponds to a portion of the calibration scale, while the field of view of the second line scan camera 122 corresponds to a portion of the calibration scale. As shown in Figure 6, in some cases, the first line scan camera 121 and the second line scan camera 122 have overlapping fields of view. For example, the length of the overlapping area can be designed to be 30 mm.

[0089] It should be noted that although two line scan cameras are described above as being arranged side by side, the scope of the present application is not limited thereto. For example, only one line scan camera may be provided, or three or more line scan cameras may be provided side by side. The number of line scan cameras is set according to actual needs.

[0090] In some embodiments, controller 150 is configured to determine the overlapping fields of view of the multiple line scan cameras when all of the multiple line scan cameras capture images containing the third calibration block. In this embodiment, the overlapping fields of view of the multiple line scan cameras are determined, thereby facilitating the removal of overlapping fields of view during precision calibration and improving camera calibration accuracy.

[0091] For example, the first part of the first calibration block and the second part of the second calibration block on the calibration ruler are moved to the camera's photo point. The camera's internal trigger is used to capture images. The camera's posture is adjusted until both cameras capture black and white images. The images are saved, indicating that the two camera photo points are collinear. The cameras are then fixed. The photo roller is rotated so that the photo point is the third calibration block in the middle of the calibration ruler. Using the internal trigger, the cameras are adjusted left and right so that the right end of the first line scan camera and the left end of the second line scan camera can both capture the third calibration block. The images are captured and saved, and the overlapping fields of view of the two cameras are confirmed based on the third calibration block in the middle of the calibration ruler. This allows for the determination of the overlapping fields of view of multiple line scan cameras.

[0092] In some embodiments, each of the plurality of line scan cameras is configured to capture a first image when triggered by the second trigger signal, thereby enabling the plurality of line scan cameras to capture multiple first images. For example, the first line scan camera 121 and the second line scan camera 122 may each capture a first image of the calibration ruler when triggered by the second trigger signal, thereby capturing two first images.

[0093] In some embodiments, controller 150 is configured to remove overlapping portions of the multiple first images based on the overlapping fields of view of the multiple line scan cameras, stitch the multiple first images after removing the overlapping portions into a third image, and calculate the lateral accuracy based on the third image. In this embodiment, by removing overlapping portions of the multiple first images to stitch the images into the third image, and then calculating the lateral accuracy of the camera based on the third image, the lateral calibration accuracy of the camera is improved.

[0094] In some embodiments, the controller 150 is configured to calculate the lateral accuracy corresponding to the area between two adjacent edges in the first and second sections that are alternately arranged on the same straight line based on the lateral length of the area between the two adjacent edges and the lateral pixel positions of the two adjacent edges. This enables calculation of the camera's lateral accuracy and improves the camera's lateral calibration accuracy.

[0095] FIG15 is a schematic diagram showing black and white images of a calibration ruler taken after stitching according to some embodiments of the present application.

[0096] For example, FIG15 shows a first portion 511 of a first calibration block 510 and a second portion 522 of a second calibration block 520 arranged alternately on the same straight line in a stitched third image. Thus, the relationship for calculating the lateral accuracy of the camera is:

[0097] Among them, H i,i+1 W is the lateral accuracy of the area between the ith edge and the i+1th edge in the first and second parts alternately arranged on the same straight line, i,i+1 is the horizontal length of the area between the ith edge and the i+1th edge, X i+1 is the horizontal pixel position of the i+1th edge, X i is the horizontal pixel position of the i-th edge, i ≥ 1 and i is a positive integer.

[0098] Here, the horizontal pixel position refers to the pixel position of the image corresponding to a certain edge in the horizontal direction (i.e., the pixel number in the horizontal direction of the image). In some embodiments, each of the plurality of line scan cameras is configured to capture a second image upon receiving the first trigger signal, thereby enabling the plurality of line scan cameras to capture a plurality of second images.

[0099] For example, the camera triggering mode is changed to encoder triggering, and the photographing roller is rotated. After receiving the first triggering signal from the encoder, the first line scan camera 121 and the second line scan camera 122 both take pictures to obtain the second image, thereby obtaining two second images.

[0100] In some embodiments, controller 150 is configured to remove overlapping portions of the plurality of second images based on the overlapping fields of view of the plurality of line scan cameras, stitch the plurality of second images after removing the overlapping portions into a fourth image, and calculate the longitudinal accuracy based on the fourth image. In this embodiment, by removing overlapping portions of the plurality of second images, stitching them into the fourth image, and then calculating the longitudinal accuracy based on the fourth image, the longitudinal calibration accuracy of the camera is improved.

[0101] In some embodiments, controller 150 is configured to calculate the longitudinal accuracy corresponding to the area between two edges in the first and second portions, which are alternately arranged on the same straight line, based on the longitudinal length of the first calibration block or the second calibration block between the two edges, and the longitudinal pixel positions of the lower edge and the upper edge of the first calibration block or the second calibration block between the two edges. This enables calculation of the longitudinal accuracy of the camera, thereby improving the longitudinal calibration accuracy of the camera.

[0102] FIG16 is a schematic diagram showing stitched images of photographed calibration rulers according to other embodiments of the present application.

[0103] For example, FIG16 shows the first calibration block 510 and the second calibration block 520 in the stitched fourth image. Thus, the relationship for calculating the longitudinal accuracy of the camera is:

[0104] Among them, L j,j+2 is the jth edge (X j ') to the j+2th edge (X j+2 ') in the longitudinal accuracy of the area between j,j+1 Y is the longitudinal length of the first calibration block or the second calibration block between the jth edge and the j+2th edge, j+1 Y is the vertical pixel position of the lower edge of the first calibration block or the second calibration block between the jth edge and the j+2th edge, j is the vertical pixel position of the upper edge of the first calibration block or the second calibration block between the jth edge and the j+2th edge, where j≥1 and j is a positive integer.

[0105] Here, the vertical pixel position refers to the pixel position of the image corresponding to a certain edge in the vertical direction (ie, the pixel number in the vertical direction of the image).

[0106] FIG7 is a flow chart illustrating a method for calibrating a coating system according to some embodiments of the present application. The coating system includes: a first roller and a second roller; a calibration ruler disposed on the first roller or the second roller, comprising a plurality of calibration blocks arranged in an interlaced manner; an encoder coaxially mounted with the first roller or the second roller, or mounted on a bracket and contacting the first roller or the second roller using a pressure wheel; one or more line scan cameras disposed on one side of the first roller or the second roller, wherein the field of view of the one or more line scan cameras corresponds to the calibration ruler; and a controller. As shown in FIG7 , the calibration method includes steps S702 to S706.

[0107] In step S702, the encoder generates a first trigger signal driven by the first roller or the second roller.

[0108] In step S704 , after receiving the first trigger signal or being triggered by the second trigger signal inside the line scan camera, the line scan camera takes a picture of the calibration ruler to obtain an image.

[0109] In step S706 , the controller calculates at least one of a lateral accuracy and a longitudinal accuracy of the line scan camera according to the image.

[0110] Thus, a coating system calibration method according to some embodiments of the present application is provided. The calibration method includes: an encoder generates a first trigger signal driven by a first roller or a second roller; a line scan camera photographs a calibration ruler to obtain an image after receiving the first trigger signal or when triggered by a second trigger signal within the line scan camera; and a controller calculates at least one of the lateral accuracy and longitudinal accuracy of the line scan camera based on the image. This improves the calibration accuracy of the coating system's camera.

[0111] In some embodiments, a calibration ruler includes: a plurality of first calibration blocks spaced apart in a first row and a plurality of second calibration blocks spaced apart in a second row, the plurality of first calibration blocks and the plurality of second calibration blocks being arranged in an alternating pattern, with the first portion of each first calibration block and the second portion of each second calibration block being aligned on the same line; the calibration ruler is aligned with the first roller along a positioning line on the first roller, or aligned with the second roller along a positioning line on the second roller; a line scan camera photographs the calibration ruler to obtain an image upon receiving a first trigger signal or triggered by a second trigger signal within the line scan camera, including: the line scan camera photographs the calibration ruler to obtain a first image upon triggering by the second trigger signal; and a controller calculates at least one of a lateral accuracy and a longitudinal accuracy of the line scan camera based on the image, including: the controller calculates the lateral accuracy based on the first image when one or more line scan cameras are triggered by the second trigger signal to obtain the first image, wherein the first image includes first and second portions alternating on the same line. In this embodiment, the first image is captured by in-camera triggering, thereby facilitating calculation of the camera's lateral calibration accuracy.

[0112] In some embodiments, after receiving a first trigger signal or triggered by a second trigger signal within the line scan camera, the line scan camera photographs the calibration ruler to obtain an image, including: the line scan camera photographs the calibration ruler to obtain a second image after receiving the first trigger signal; and the controller calculates at least one of the lateral accuracy and longitudinal accuracy of the line scan camera based on the image, including: when one or more line scan cameras photograph and obtain the second image after receiving the first trigger signal, the controller calculates the longitudinal accuracy based on the second image, wherein the second image includes multiple first calibration blocks and multiple second calibration blocks. In this embodiment, the line scan camera is triggered by an encoder to capture the second image, thereby facilitating the calculation of the camera's longitudinal calibration accuracy.

[0113] In some embodiments, the calibration ruler further includes: a third calibration block in a row different from the first row and the second row. The one or more line scan cameras include a plurality of line scan cameras, wherein the plurality of line scan cameras are arranged side by side, the photographing points of the plurality of line scan cameras are collinear, and the photographing field of view of each of the plurality of line scan cameras corresponds to a portion of the calibration ruler. The calibration method further includes: when the plurality of line scan cameras all take photos to obtain images containing the third calibration block, the controller determines the overlapping fields of view of the plurality of line scan cameras. In this embodiment, the determination of the overlapping fields of view of the plurality of line scan cameras is realized, thereby facilitating the removal of overlapping fields of view during the precision calibration process and improving the calibration accuracy of the camera.

[0114] In some embodiments, a line scan camera photographs the calibration ruler in response to a second trigger signal to obtain a first image, including: each of the plurality of line scan cameras photographs the calibration ruler in response to the second trigger signal to obtain a first image, thereby allowing the plurality of line scan cameras to obtain a plurality of first images; and a controller calculates the lateral accuracy based on the first images when one or more line scan cameras photograph the first images in response to the second trigger signal, including: the controller removes overlapping portions of the plurality of first images based on overlapping fields of view of the plurality of line scan cameras, splices the plurality of first images after the overlapping portions are removed into a third image, and calculates the lateral accuracy based on the third image. In this embodiment, by removing overlapping portions of the plurality of first images to splice the images into the third image, and calculating the lateral accuracy of the camera based on the third image, the lateral calibration accuracy of the camera is improved.

[0115] In some embodiments, the controller calculating the lateral accuracy based on the third image includes: the controller calculating the lateral accuracy corresponding to the area between two adjacent edges in the first and second portions that are alternately arranged on the same straight line based on the lateral length of the area between the two adjacent edges and the lateral pixel positions of the two adjacent edges. This enables calculation of the lateral accuracy of the camera, thereby improving the lateral calibration accuracy of the camera.

[0116] In some embodiments, after receiving a first trigger signal, a line scan camera photographs the calibration ruler to obtain a second image, including: each of the plurality of line scan cameras photographs the calibration ruler to obtain a second image after receiving the first trigger signal, thereby allowing the plurality of line scan cameras to obtain a plurality of second images; and when one or more line scan cameras photograph the calibration ruler to obtain a second image after receiving the first trigger signal, a controller calculates the longitudinal accuracy based on the second image, including: the controller removes overlapping portions of the plurality of second images based on the overlapping fields of view of the plurality of line scan cameras, splices the plurality of second images after the overlapping portions are removed into a fourth image, and calculates the longitudinal accuracy based on the fourth image. In this embodiment, by removing overlapping portions of the plurality of second images and splicing them into the fourth image, and then calculating the longitudinal accuracy based on the fourth image, the longitudinal calibration accuracy of the camera is improved.

[0117] In some embodiments, the controller calculating the longitudinal accuracy based on the fourth image includes: the controller calculating the longitudinal accuracy corresponding to the area between the two edges based on the longitudinal length of the first calibration block or the second calibration block between the two edges in the first and second portions that are alternately arranged on the same straight line, and the longitudinal pixel positions of the lower edge and the upper edge of the first calibration block or the second calibration block between the two edges. This enables calculation of the longitudinal accuracy of the camera, thereby improving the longitudinal calibration accuracy of the camera.

[0118] FIG8 is a flow chart illustrating a method for calibrating a coating system according to another embodiment of the present invention. As shown in FIG8 , the calibration method includes steps S802 to S810. The following description is based on an example in which a line scan camera includes a first line scan camera 121 and a second line scan camera 122.

[0119] In step S802, a calibration ruler is attached to the photographing roller. For example, the photographing roller is the first roller or the second roller. The upper end of the calibration ruler is attached to the photographing roller along the positioning line of the photographing roller, as shown in FIG5 .

[0120] In step S804, the camera is adjusted using internal triggering until a black and white image is captured. For example, the horizontally overlapping portion of the black block of the calibration ruler (i.e., the first portion 511 of the first calibration block 510 and the second portion 522 of the second calibration block 520) is moved to the line scan camera's capture point. The line scan camera captures an image under the second trigger signal. That is, the camera's internal triggering is used to capture the image. The camera's posture is adjusted until both cameras capture black and white images. The image is saved, indicating that the two camera capture points are collinear. The cameras are then fixed.

[0121] In step S806, rotate the photo roller so that the photo point is located in the third calibration block. Use the internal trigger to adjust the camera left and right until both cameras can capture the third calibration block and the brightness of the white area in the picture is uniform. Fix the camera and calculate the camera overlap area based on the picture.

[0122] Figure 11 is a schematic diagram illustrating images captured by line scan cameras according to some embodiments of the present application. Figure 11 shows a first image 411 captured by a first line scan camera and a second image 412 captured by a second line scan camera. Specifically, the right end of the first line scan camera and the left end of the second line scan camera are both able to capture images of the third calibration block. The images are captured and saved, and the overlapping fields of view of the two cameras are confirmed using the third calibration block in the middle of the calibration scale.

[0123] The main processes (1) to (3) of calculating the visual field overlap area in step S806 are described in detail below.

[0124] Here, the total number of horizontal pixels of the first image 411 is T1, and the total number of horizontal pixels of the second image 412 is T2. For example, T1=T2=T.

[0125] In step (1), the right edge position or the left edge position of the third calibration block in the calibration ruler is located using the straight line search method in the image processing algorithm. For example, as shown in FIG11 , the horizontal pixel position E1 of the pixel where the right edge is located is output, and the overlapping area removed by the first line scan camera is (E1, T1].

[0126] In step (2), similarly, for the second image 412 taken by the second line scan camera, the right edge position or the left edge position of the third calibration block of the calibration ruler is located. For example, as shown in FIG11 , the horizontal pixel position E2 of the pixel where the right edge is located is output, and the overlapping area that needs to be removed by the second line scan camera is [0, E2].

[0127] In step (3), the images after removing the overlapping areas are spliced ​​to obtain a spliced ​​image, for example, as shown in FIG13 .

[0128] In step S808, the black and white image from step S804 is acquired again, the overlapping fields of view are removed, and then lateral calibration is performed. Here, the captured images are combined into a complete black and white image (i.e., the third image described above), and the lateral accuracy of the camera is calibrated block by block.

[0129] As shown in FIG12 , the first line scan camera captures a first image 421, and the second line scan camera captures another first image 422. The controller removes the overlapping portions of the two first images 421 and 422 based on the overlapping fields of view of the first and second line scan cameras, stitches the two first images after removing the overlapping portions into a third image (e.g., as shown in FIG15 ), and calculates the lateral accuracy based on the third image.

[0130] In step S808, the process of calibrating the camera's lateral accuracy is as follows:

[0131] (1) The first line scan camera and the second line scan camera capture images through internal triggering, and the resulting stitched image is shown in FIG15 .

[0132] (2) The relationship for calculating the lateral accuracy of the camera is:

[0133] Among them, H i,i+1 W is the lateral accuracy of the area between the ith edge and the i+1th edge in the first and second parts alternately arranged on the same straight line, i,i+1 is the horizontal length of the area between the ith edge and the (i+1)th edge (for example, the distance between two black stripes is W i,i+1 ), X i+1 is the horizontal pixel position of the i+1th edge (i.e., the pixel position of the i+1th edge in the image), X i is the horizontal pixel position of the i-th edge (i.e., the pixel position of the i-th edge in the image), i≥1 and i is a positive integer. Here,

[0134] For example, the width of each black bar and white bar (i.e., the part between the two black bars) is equal, both D mm. Use the edge grabbing tool in the image algorithm to obtain the edge position of each black and white bar {X1, X2, X3, ..., Xn-1 , X n The lateral accuracy of the area (X1, X2) is: W 1,2 / (X2-X1)=D / (X2-X1), the horizontal direction of the [X2, X3] area is: D / (X3-X2), and the same applies to the remaining areas.

[0135] In addition, the horizontal pixel accuracy of [0, X1] can use the value of (X1, X2] area calibration. Similarly, (X n , the lateral accuracy of the area T+E1-E2) is calculated using D / (X n -X n-1 ), where T+E1-E2 is the horizontal pixel position of the rightmost edge of the spliced ​​image. Here, the horizontal pixel position of the rightmost edge of the spliced ​​image is calculated as 2T-(T-E1+E2)=T+E1-E2.

[0136] In step S810, the camera triggering mode is changed to encoder triggering, and the photo roller is rotated to obtain a complete image of the calibration ruler for longitudinal calibration. For example, after the encoder triggers the camera to take a photo, the captured image is saved, and after removing the overlapping areas, the camera longitudinal calibration accuracy is calculated block by block.

[0137] For example, the first line scan camera and the second line scan camera both take pictures after receiving the first trigger signal from the encoder, thereby obtaining two second images; the controller removes the overlapping parts of the two second images according to the overlapping fields of view of the two line scan cameras, splices the two second images after removing the overlapping parts into a fourth image (for example, as shown in FIG14 ), and calculates the longitudinal accuracy based on the fourth image.

[0138] In step S810, the process of calibrating the longitudinal accuracy of the camera is as follows:

[0139] (1) After the encoder is triggered, the camera captures pictures, and the controller stitches the pictures to obtain the fourth image, as shown in FIG14 .

[0140] (2) For example, FIG16 shows the first calibration block 510 and the second calibration block 520 in the fourth image stitched together. Thus, the relationship for calculating the longitudinal accuracy of the camera is:

[0141] Among them, L j,j+2 is the jth edge (X j ') to the j+2th edge (X j+2 ') in the longitudinal accuracy of the area between j,j+1 Y is the longitudinal length of the first calibration block or the second calibration block between the jth edge and the j+2th edge, j+1Y is the vertical pixel position of the lower edge of the first calibration block or the second calibration block between the jth edge and the j+2th edge, j is the vertical pixel position of the upper edge of the first calibration block or the second calibration block between the jth edge and the j+2th edge, where j≥1 and j is a positive integer.

[0142] For example, the height of each black bar is h2, that is, H j,j+1 = h2, use the edge grabbing tool in the image algorithm to obtain the horizontal edge position of each black bar {X1', X2', X3', ..., X' n-1 , X' n The longitudinal accuracy of the area (X1', X3') is: h2 / (Y2-Y1), the longitudinal accuracy of the area (X3, X5) is: h2 / (Y4-Y3), and the same applies to the remaining areas.

[0143] In addition, the vertical pixel accuracy of [0, X1'] can use the value of (X1', X3'] area calibration. Similarly, (X' n , the longitudinal accuracy of the area T+E1-E2) can be calculated using h2 / (Y n -Y n-1 ).

[0144] So far, a calibration method for a coating system according to other embodiments of the present application is provided. In this calibration method, the camera debugging work is independent of the main equipment and does not rely on the electrode produced by the main equipment, so that the camera calibration work can be carried out independently, reducing the time for debugging the line scan camera and improving the debugging efficiency. This calibration method makes the camera calibration independent of the coating variety. When the production line is cut and pulled, the camera does not need to be recalibrated. The use of a high-precision calibration ruler reduces the human measurement error caused by manual measurement of the extremely wide film width size information, improves the calibration accuracy of the camera, and thus improves the measurement accuracy of the coating system.

[0145] FIG17 is a schematic diagram illustrating how to obtain pole piece dimensions according to some embodiments of the present application.

[0146] After the camera is calibrated, the electrode can be coated on the coating system. As shown in Figure 17, for example, the size of the area between the electrode position N0 and position N1 can be calculated as follows:

[0147] As mentioned above, D is the width of each black bar and white bar, and X1, X2, X3, and X4 are the pixel positions of the four edges.

[0148] In this way, after the above-mentioned precision calibration, the dimensions of certain parts of the pole piece can be calculated.

[0149] So far, the various embodiments of the present application have been described in detail. To avoid obscuring the concept of the present application, some details well known in the art have not been described. Based on the above description, those skilled in the art can fully understand how to implement the technical solutions disclosed herein.

[0150] Although some specific embodiments of the present application have been described in detail through examples, those skilled in the art will understand that the above examples are for illustration only and are not intended to limit the scope of the present application. Those skilled in the art will understand that the above embodiments may be modified or some technical features may be replaced with equivalents without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A coating system comprising: A first roller and a second roller; A calibration ruler, arranged on the first passing roller or the second passing roller, comprising a plurality of calibration blocks arranged in a staggered manner; An encoder is coaxially mounted with the first roller or the second roller, or is mounted on a bracket and contacts the first roller or the second roller in a pressure wheel mounting manner, and is configured to generate a first trigger signal driven by the first roller or the second roller; One or more line scan cameras are arranged on one side of the first roller or the second roller, wherein the photographing field of the one or more line scan cameras corresponds to the calibration ruler, and the line scan camera is configured to photograph the calibration ruler to obtain an image after receiving the first trigger signal or under the triggering of a second trigger signal inside the line scan camera; and A controller is configured to calculate at least one of a lateral accuracy and a longitudinal accuracy of the line scan camera based on the image.

2. The coating system according to claim 1, further comprising: The acquisition card is electrically connected to the encoder and to one or more line scan cameras, and is configured to receive the first trigger signal from the encoder, send the first trigger signal to the one or more line scan cameras, receive an image obtained by taking pictures by the one or more line scan cameras, and send the image to the controller.

3. The coating system according to claim 1 or 2, wherein: The calibration ruler comprises: a plurality of first calibration blocks spaced apart in a first row and a plurality of second calibration blocks spaced apart in a second row, the plurality of first calibration blocks and the plurality of second calibration blocks being arranged alternately, and a first portion of each first calibration block and a second portion of each second calibration block being arranged on the same straight line; The calibration ruler is attached to the first roller along the positioning line on the first roller, or is attached to the second roller along the positioning line on the second roller. The line scan camera takes a picture of the calibration ruler to obtain a first image when triggered by the second trigger signal, and takes a picture of the calibration ruler to obtain a second image after receiving the first trigger signal.

4. The coating system according to claim 3, wherein: The calibration ruler further includes: a third calibration block located in a row different from the first row and the second row.

5. The coating system according to claim 4, wherein: The third calibration block is aligned with a second calibration block among the plurality of second calibration blocks in a direction perpendicular to an extension direction of the second row.

6. The coating system according to any one of claims 3 to 5, wherein: The controller is configured to calculate the lateral accuracy based on a first image when the one or more line scan cameras are triggered by the second trigger signal to take a picture to obtain a first image, wherein the first image includes the first part and the second part alternately arranged on the same straight line.

7. The coating system according to any one of claims 3 to 6, wherein: The controller is configured to calculate the longitudinal accuracy based on a second image when the one or more line scan cameras obtain a second image by photographing the second image after receiving the first trigger signal, wherein the second image includes the plurality of first calibration blocks and the plurality of second calibration blocks.

8. A coating system according to any one of claims 4 to 7, wherein: The one or more line scan cameras include a plurality of line scan cameras, wherein the plurality of line scan cameras are arranged side by side, the photographing points of the plurality of line scan cameras are collinear, and the photographing field of view of each of the plurality of line scan cameras corresponds to a portion of the calibration ruler; The controller is configured to determine the overlapping fields of view of the plurality of line scan cameras when the plurality of line scan cameras all take photos to obtain images including the third calibration block.

9. The coating system according to claim 8, wherein: Each of the plurality of line scan cameras is configured to take a photo to obtain a first image when triggered by the second trigger signal, so that the plurality of line scan cameras obtain a plurality of first images; The controller is configured to remove overlapping portions of the multiple first images according to overlapping fields of view of the multiple line scan cameras, stitch the multiple first images after removing the overlapping portions into a third image, and calculate the lateral accuracy based on the third image.

10. The coating system according to claim 6, wherein: The controller is configured to calculate a lateral accuracy corresponding to the area between two adjacent edges in the first part and the second part alternately arranged on the same straight line based on a lateral length of the area between the two adjacent edges and a lateral pixel position of the two adjacent edges.

11. The coating system according to claim 8, wherein: Each of the plurality of line scan cameras is configured to take a photo to obtain a second image after receiving the first trigger signal, so that the plurality of line scan cameras obtain a plurality of second images; The controller is configured to remove overlapping portions of the plurality of second images according to overlapping fields of view of the plurality of line scan cameras, stitch the plurality of second images after removing the overlapping portions into a fourth image, and calculate the longitudinal accuracy according to the fourth image.

12. The coating system according to claim 7, wherein: The controller is configured to determine the length of the first calibration block or the second calibration block between two edges of the first part and the second part alternately arranged on the same straight line, and the length of the first calibration block or the second calibration block between the two edges. The longitudinal pixel position of the lower edge and the longitudinal pixel position of the upper edge of the first calibration block or the second calibration block are calculated to obtain the longitudinal accuracy corresponding to the area between the two edges.

13. A method for calibrating a coating system, the coating system comprising: A first roller and a second roller; A calibration ruler, arranged on the first passing roller or the second passing roller, comprising a plurality of calibration blocks arranged in a staggered manner; An encoder is coaxially mounted with the first roller or the second roller, or is mounted on a bracket and contacts the first roller or the second roller in a pressure wheel mounting manner; One or more line scan cameras, arranged on one side of the first roller or the second roller, wherein the photographing field of the one or more line scan cameras corresponds to the calibration ruler; and a controller; The calibration method comprises: The encoder generates a first trigger signal driven by the first roller or the second roller; The line scan camera takes a picture of the calibration ruler to obtain an image after receiving the first trigger signal or under the triggering of a second trigger signal inside the line scan camera; and The controller calculates at least one of a lateral accuracy and a longitudinal accuracy of the line scan camera based on the image.

14. The calibration method according to claim 13, wherein: The calibration ruler comprises: a plurality of first calibration blocks spaced apart in a first row and a plurality of second calibration blocks spaced apart in a second row, the plurality of first calibration blocks and the plurality of second calibration blocks being arranged alternately, and a first portion of each first calibration block and a second portion of each second calibration block being arranged on the same straight line; The calibration ruler is attached to the first roller along the positioning line on the first roller, or is attached to the second roller along the positioning line on the second roller; After receiving the first trigger signal or triggered by a second trigger signal inside the line scan camera, the line scan camera takes a picture of the calibration ruler to obtain an image, comprising: the line scan camera takes a picture of the calibration ruler to obtain a first image under the triggering of the second trigger signal; The controller calculates at least one of the lateral accuracy and the longitudinal accuracy of the line scan camera based on the image, including: when the one or more line scan cameras take a picture to obtain a first image under the triggering of the second trigger signal, the controller calculates the lateral accuracy based on the first image, wherein the first image contains the first part and the second part alternately arranged on the same straight line.

15. The calibration method according to claim 14, wherein: After receiving the first trigger signal or triggered by a second trigger signal inside the line scan camera, the line scan camera takes a picture of the calibration ruler to obtain an image, comprising: after receiving the first trigger signal, the line scan camera takes a picture of the calibration ruler to obtain a second image; The controller calculates at least one of the lateral accuracy and the longitudinal accuracy of the line scan camera based on the image, including: when the one or more line scan cameras take a photo to obtain a second image after receiving the first trigger signal, the controller calculates the longitudinal accuracy based on the second image, wherein the second image includes the multiple first calibration blocks and the multiple second calibration blocks.

16. The calibration method according to any one of claims 14 to 15, wherein: The calibration ruler further includes: a third calibration block in a row different from the first row and the second row; The one or more line scan cameras include a plurality of line scan cameras, wherein the plurality of line scan cameras are arranged side by side, the photographing points of the plurality of line scan cameras are collinear, and the photographing field of view of each of the plurality of line scan cameras corresponds to a portion of the calibration ruler; The calibration method further comprises: The controller determines the overlapping fields of view of the plurality of line scan cameras when the plurality of line scan cameras all take photos to obtain images including the third calibration block.

17. The calibration method according to any one of claims 14 to 16, wherein: The line scan camera photographs the calibration ruler under the triggering of the second trigger signal to obtain a first image, comprising: each of the plurality of line scan cameras photographs under the triggering of the second trigger signal to obtain a first image, so that the plurality of line scan cameras obtain a plurality of first images; When the one or more line scan cameras take a picture to obtain a first image under the triggering of the second trigger signal, the controller calculates the lateral accuracy based on the first image, including: the controller removes the overlapping parts of the multiple first images according to the overlapping fields of view of the multiple line scan cameras, splices the multiple first images after removing the overlapping parts into a third image, and calculates the lateral accuracy based on the third image.

18. The calibration method according to claim 17, wherein: The controller calculating the lateral accuracy according to the third image includes: The controller calculates a lateral accuracy corresponding to the area between two adjacent edges in the first part and the second part alternately arranged on the same straight line according to a lateral length of the area between two adjacent edges and lateral pixel positions of the two adjacent edges.

19. The calibration method according to any one of claims 15 to 18, wherein: The line scan camera takes a picture of the calibration ruler to obtain a second image after receiving the first trigger signal, comprising: each of the plurality of line scan cameras takes a picture to obtain a second image after receiving the first trigger signal, so that the plurality of line scan cameras obtain a plurality of second images; When the one or more line scan cameras obtain a second image by photographing after receiving the first trigger signal, the controller calculates the longitudinal accuracy based on the second image, including: the controller removes overlapping parts of the multiple second images according to the overlapping fields of view of the multiple line scan cameras, splices the multiple second images after removing the overlapping parts into a fourth image, and calculates the longitudinal accuracy based on the fourth image.

20. The calibration method according to claim 19, wherein: The controller calculating the longitudinal accuracy according to the fourth image includes: The controller calculates the first calibration block or the second calibration block according to the longitudinal length of the first calibration block or the second calibration block between the two edges of the first part and the second part alternately arranged on the same straight line, and the longitudinal pixel position of the lower edge and the longitudinal pixel position of the upper edge of the first calibration block or the second calibration block between the two edges. The area between the two edges corresponds to the longitudinal accuracy.

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