Line laser profiler installation angle error calibration method and device and computing equipment

Abstract

This invention discloses a method, apparatus, and computing device for calibrating the installation angle error of a line laser profilometer. The method includes: acquiring first contour data of a spherical target collected by the line laser profilometer; determining the coordinates of a first center of a circle corresponding to the first contour data using a planar circle fitting algorithm; acquiring second contour data of the spherical target collected by the line laser profilometer after moving the target a distance along a linear guide rail; determining the coordinates of a second center of a circle corresponding to the second contour data using a planar circle fitting algorithm; and determining the installation angle error of the line laser profilometer based on the first center coordinates, the second center coordinates, and the target distance. Based on this, the calibration process for the installation angle error of a line laser profilometer can be simplified, calibration costs reduced, and the versatility of the calibration improved.

Description

Technical Field

[0001] This invention relates to the field of three-dimensional measurement technology, and in particular to a method for calibrating the installation angle error of a line laser profilometer, a device for calibrating the installation angle error of a line laser profilometer, and a computing device. Background Technology

[0002] Line laser profilometers are widely used in 3D measurement due to their reliable measurement accuracy, high efficiency, and non-contact operation. In practical engineering applications, line laser profilometers need to work in conjunction with mechanisms such as linear guides, relying on linear movement along the guides to assist in acquiring 3D topographic data of the target surface. However, installation angle errors can easily occur during the installation of line laser profilometers, causing them to deviate from the direction of the linear guides, which in turn leads to distortion of the acquired 3D topographic data. Therefore, calibrating the installation angle error of line laser profilometers is crucial for their engineering applications.

[0003] Calibration of the mounting angle error of a line laser profilometer is a crucial step in achieving accurate 3D topographic reconstruction, and the calibration result directly affects the accuracy of the scanning data. Currently, widely used line laser profilometer mounting angle calibration schemes mainly rely on specially shaped, high-precision calibration objects, which are costly, complex to operate, and require highly skilled personnel.

[0004] Therefore, a method for calibrating the installation angle error of a line laser profilometer is needed to solve the problems existing in the above technical solutions. Summary of the Invention

[0005] Therefore, the present invention provides a method and apparatus for calibrating the installation angle error of a line laser profilometer, so as to solve or at least alleviate the above-mentioned problems.

[0006] According to one aspect of the present invention, a method for calibrating the installation angle error of a line laser profilometer is provided, executed in a computing device, wherein the installation angle error of the line laser profilometer is the angular deviation between the line laser profilometer and the direction of a linear guide rail, the method comprising: acquiring first contour data of a spherical target collected by the line laser profilometer; determining the first center coordinates corresponding to the first contour data using a planar circle fitting algorithm; acquiring second contour data of the spherical target collected by the line laser profilometer after moving a target distance linearly along the linear guide rail; determining the second center coordinates corresponding to the second contour data using a planar circle fitting algorithm; and determining the installation angle error of the line laser profilometer based on the first center coordinates, the second center coordinates, and the target distance.

[0007] Optionally, in the method for calibrating the installation angle error of the line laser profilometer according to the present invention, acquiring the first contour data of the spherical target collected by the line laser profilometer includes: emitting a line laser to the spherical target through the line laser profilometer located at a first position to acquire the first contour data of the spherical target, wherein the first contour data is a first circular contour generated by the intersection of the first laser plane of the line laser profilometer located at the first position and the spherical target; and acquiring the first contour data of the spherical target collected by the line laser profilometer.

[0008] Optionally, in the method for calibrating the installation angle error of a line laser profilometer according to the present invention, the straight line passing through the first center coordinate and the second center coordinate is perpendicular to the first laser plane and the second laser plane; the first center coordinate is represented as (x1, y1), and the second center coordinate is represented as (x2, y2); the installation angle error of the line laser profilometer includes a first installation angle error and a second installation angle error; determining the installation angle error of the line laser profilometer based on the first center coordinate, the second center coordinate, and the target distance includes: calculating the first installation angle error and the second installation angle error according to the following formulas: α=arcsin((y2-y1) / d); β=arccos((x2-x1) / d); where α represents the first installation angle error, β represents the second installation angle error, and d represents the target distance.

[0009] Optionally, the method for calibrating the installation angle error of a line laser profilometer according to the present invention further includes: establishing a coordinate system for the line laser profilometer by taking the laser emission direction of the line laser profilometer located at the first position as the Y-axis direction, the normal direction of the first laser plane of the line laser profilometer as the Z-axis direction, and the direction perpendicular to the Y-axis direction on the first laser plane of the laser profilometer as the X-axis direction; wherein, the first installation angle error is the installation angle error of the line laser profilometer around the X-axis, and the second installation angle error is the installation angle error of the line laser profilometer around the Y-axis.

[0010] Optionally, in the line laser profilometer installation angle error calibration method according to the present invention, the first circle center coordinates corresponding to the first contour data are determined using a planar circle fitting algorithm, including the following steps: randomly selecting three first data points that are not on the same straight line from the first contour data; determining the first planar circle parameters fitted by the three first data points, wherein the first planar circle parameters include the first planar circle center coordinates and the first planar circle radius; calculating the root mean square error of the difference between the distance from all the first data points in the first contour data to the first planar circle center coordinates and the first planar circle radius; repeating the above steps until the number of executions reaches a predetermined number, and selecting the first planar circle center coordinates and the first planar circle radius with the smallest root mean square error. The radius of the face circle is used as the first initial circle center coordinate and the first initial radius, respectively. The deviation value between the distance of each first data point in the first contour data to the first initial circle center coordinate and the first initial radius is calculated, and the mean and variance of the deviation values ​​of all first data points are calculated. Each first data point in the first contour data whose difference between the deviation value and the mean deviation value is greater than three times the variance of the deviation value is removed to obtain the first initial contour data. Based on the first initial contour data, the first initial circle center coordinate and the first initial radius, the first target plane circle is obtained by fitting using the least squares method, and the center coordinate of the first target plane circle is determined as the first circle center coordinate corresponding to the first contour data.

[0011] Optionally, in the line laser profilometer installation angle error calibration method according to the present invention, the second circle center coordinates corresponding to the second contour data are determined using a planar circle fitting algorithm, including the following steps: randomly selecting three second data points that are not on the same straight line from the second contour data; determining the second planar circle parameters fitted by the three second data points, wherein the second planar circle parameters include the second planar circle center coordinates and the second planar circle radius; calculating the root mean square error of the difference between the distance from all second data points in the second contour data to the second planar circle center coordinates and the second planar circle radius; repeating the above steps until the number of executions reaches a predetermined number, and selecting the second planar circle center coordinates and the second planar circle radius with the smallest root mean square error. The radius of the face circle is used as the second initial circle center coordinate and the second initial radius, respectively. The deviation value between the distance of each second data point in the second contour data to the second initial circle center coordinate and the second initial radius is calculated, and the mean and variance of the deviation values ​​of all second data points are calculated. Each second data point in the second contour data whose difference between the deviation value and the mean deviation value is greater than three times the variance of the deviation value is removed to obtain the second initial contour data. Based on the second initial contour data, the second initial circle center coordinate, and the second initial radius, the second target plane circle is obtained by fitting using the least squares method, and the center coordinate of the second target plane circle is determined as the second circle center coordinate corresponding to the second contour data.

[0012] According to one aspect of the present invention, a calibration device for the installation angle error of a line laser profilometer is provided, deployed in a computing device, adapted to perform the method described above, wherein the installation angle error of the line laser profilometer is the angular deviation between the line laser profilometer and the direction of the linear guide rail, the device comprising: a first acquisition module, adapted to acquire first contour data of a spherical target collected by the line laser profilometer; a first determination module, adapted to determine the first center coordinates corresponding to the first contour data using a planar circle fitting algorithm; a second acquisition module, adapted to acquire second contour data of the spherical target collected by the line laser profilometer after moving a target distance linearly along the linear guide rail; a second determination module, adapted to determine the second center coordinates corresponding to the second contour data using a planar circle fitting algorithm; and an error determination module, adapted to determine the installation angle error of the line laser profilometer based on the first center coordinates, the second center coordinates, and the target distance.

[0013] According to one aspect of the present invention, a computing device is provided, comprising: at least one processor; and a memory storing program instructions, wherein the program instructions are configured to be executed by the at least one processor, the program instructions including instructions for performing the line laser profilometer mounting angle error calibration method as described above.

[0014] According to one aspect of the present invention, a computer program product is provided, comprising computer program instructions, wherein the computer program instructions, when executed by a processor, implement the method as described above.

[0015] According to one aspect of the present invention, a readable storage medium storing program instructions is provided, which, when read and executed by a computing device, causes the computing device to perform the line laser profilometer mounting angle error calibration method as described above.

[0016] According to the technical solution of the present invention, a method for calibrating the installation angle error of a line laser profilometer is provided. This method involves acquiring first contour data of a spherical target collected by the line laser profilometer, determining the coordinates of the first center of a circle corresponding to the first contour data using a planar circle fitting algorithm, then acquiring second contour data of the spherical target after moving the line laser profilometer a target distance along a linear guide rail, determining the coordinates of the second center of a circle corresponding to the second contour data using the planar circle fitting algorithm, and finally determining the installation angle error of the line laser profilometer based on the first center coordinates, the second center coordinates, and the target distance. This method simplifies the calibration process for the installation angle error of the line laser profilometer, reduces calibration costs, and thus improves the versatility of the line laser profilometer installation angle error calibration.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0018] To achieve the foregoing and related objectives, certain illustrative aspects are described herein in conjunction with the following description and accompanying drawings. These aspects indicate various ways in which the principles disclosed herein may be practiced, and all aspects and their equivalents are intended to fall within the scope of the claimed subject matter. The foregoing and other objectives, features, and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings. Throughout the invention, the same reference numerals generally refer to the same parts or elements.

[0019] Figure 1 A schematic diagram of a computing device 100 provided according to an embodiment of the present invention is shown; Figure 2 A flowchart illustrating a method 200 for calibrating the installation angle error of a line laser profilometer according to an embodiment of the present invention is shown. Figure 3 A schematic diagram showing the positional relationship between the line laser profilometer and the linear guide rail direction according to an embodiment of the present invention is shown; Figure 4A schematic diagram illustrating the calculation of the first mounting angle error of a line laser profilometer about the X-axis according to some embodiments of the present invention is shown; Figure 5 A schematic diagram illustrating the calculation of the second mounting angle error of a line laser profilometer about the Y-axis according to some embodiments of the present invention is shown; Figure 6 A schematic diagram is shown illustrating the determination of the coordinates of the first circle center corresponding to the first contour data using a planar circle fitting algorithm according to some embodiments of the present invention; Figure 7 A schematic diagram of a line laser profilometer mounting angle error calibration device 700 provided according to an embodiment of the present invention is shown. Detailed Implementation

[0020] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0021] To address the issues of high cost and complex operation in existing line laser profilometer installation angle calibration schemes, this invention proposes a method for calibrating the installation angle error of a line laser profilometer. This method simplifies the calibration process, reduces calibration costs, and improves the versatility of line laser profilometer installation angle error calibration.

[0022] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0023] Figure 1 A schematic diagram of a computing device 100 according to an embodiment of the present invention is shown. Figure 1 As shown, in a basic configuration, computing device 100 includes at least one processing unit 102 and system memory 104. According to one aspect, depending on the configuration and type of the computing device, the processing unit 102 may be implemented as a processor. System memory 104 includes, but is not limited to, volatile memory (e.g., random access memory), non-volatile memory (e.g., read-only memory), flash memory, or any combination of such memories. According to one aspect, system memory 104 includes an operating system 105.

[0024] According to one aspect, operating system 105 is, for example, suitable for controlling the operation of computing device 100. Furthermore, examples are practiced in conjunction with graphics libraries, other operating systems, or any other applications, and are not limited to any particular application or system. Figure 1The basic configuration is illustrated by the components within the dashed lines. According to one aspect, the computing device 100 has additional features or functions. For example, according to one aspect, the computing device 100 includes additional data storage devices (removable and / or non-removable), such as disks, optical discs, or magnetic tapes. This additional storage... Figure 1 The middle part is shown by removable storage device 109 and non-removable storage device 110.

[0025] As stated above, according to one aspect, program module 103 is stored in system memory 104. According to one aspect, program module 103 may include one or more applications. The present invention does not limit the type of application; for example, applications may include: email and contact applications, word processing applications, spreadsheet applications, database applications, slideshow applications, drawing or computer-aided applications, web browser applications, etc.

[0026] According to one aspect, program module 103 may include a plurality of program instructions adapted to perform the line laser profilometer mounting angle error calibration method 200 of the present invention, such that computing device 100 is configured to perform the line laser profilometer mounting angle error calibration method 200 of the present invention.

[0027] According to one aspect, program module 103 may include a line laser profilometer mounting angle error calibration device 700, which may be configured to perform the line laser profilometer mounting angle error calibration method 200 of the present invention.

[0028] According to one aspect, examples can be practiced on circuits including discrete electronic components, packaged or integrated electronic chips containing logic gates, circuits utilizing microprocessors, or on a single chip containing electronic components or a microprocessor. For example, it can be practiced via wherein... Figure 1 Each or many of the components shown can be implemented as an example by integrating a System-on-a-Chip (SOC) on a single integrated circuit. According to one aspect, such an SOC device may include one or more processing units, graphics units, communication units, system virtualization units, and various application functions, all integrated (or “burned in”) as a single integrated circuit onto a chip substrate. When operating via the SOC, the functions described herein can be operated via dedicated logic integrated on a single integrated circuit (chip) with other components of the computing device 100. Embodiments of the invention can also be implemented using other techniques capable of performing logical operations (e.g., AND, OR, and NOT), including but not limited to mechanical, optical, fluid, and quantum technologies. Additionally, embodiments of the invention can be implemented within a general-purpose computer or in any other circuit or system.

[0029] According to one aspect, computing device 100 may also have one or more input devices 112, such as a keyboard, mouse, pen, voice input device, touch input device, etc. It may also include output devices 114, such as a display, speaker, printer, etc. The foregoing devices are examples and other devices may also be used. Computing device 100 may include one or more communication connections 116 that allow communication with other computing devices 118. Examples of suitable communication connections 116 include, but are not limited to: RF transmitter, receiver and / or transceiver circuitry; Universal Serial Bus (USB), parallel and / or serial ports.

[0030] As used herein, the term computer-readable medium includes computer storage medium. Computer storage medium can include volatile and non-volatile, removable and non-removable media implemented using any method or technology for storing information (e.g., computer-readable instructions, data structures, or program module 103). System memory 104, removable storage device 109, and non-removable storage device 110 are examples of computer storage media (i.e., memory storage). Computer storage media can include random access memory (RAM), read-only memory (ROM), electrically erasable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical storage, magnetic tape, magnetic tape, disk storage or other magnetic storage devices, or any other article of manufacture that can be used to store information and is accessible by computing device 100. According to one aspect, any such computer storage medium can be part of computing device 100. Computer storage media does not include carrier waves or other transmitted data signals.

[0031] According to one aspect, the communication medium is implemented by computer-readable instructions, data structures, program modules 103, or other data in a modulated data signal (e.g., a carrier wave or other transmission mechanism), and includes any information transmission medium. According to one aspect, the term "modulated data signal" describes a signal having one or more sets of characteristics or altered in a manner that encodes information in the signal. By way of example and not limitation, the communication medium includes wired media such as wired networks or direct wired connections, and wireless media such as acoustic, radio frequency (RF), infrared, and other wireless media.

[0032] In an embodiment of the present invention, a computing device 100 is configured to execute the line laser profilometer mounting angle error calibration method 200 of the present invention. The computing device 100 includes one or more processors and one or more readable storage media storing program instructions that, when configured to be executed by the one or more processors, cause the computing device to execute the line laser profilometer mounting angle error calibration method 200 of the present invention.

[0033] Figure 2 A schematic flowchart of a line laser profilometer mounting angle error calibration method 200 according to an embodiment of the present invention is shown. The line laser profilometer mounting angle error calibration method 200 can be executed in a computing device (e.g., the aforementioned computing device 100).

[0034] In an embodiment of the present invention, the computing device 100 used to perform the line laser profilometer mounting angle error calibration method 200 of the present invention may be a terminal or a server.

[0035] It should be noted that the installation angle error of the line laser profilometer is also the angular deviation between the line laser profilometer and the linear guide rail. In other words, the line laser profilometer installation angle error calibration method 200 according to the embodiments of the present invention can be used to calibrate the angular deviation between the line laser profilometer and the linear guide rail.

[0036] like Figure 2 As shown, the method 200 for calibrating the installation angle error of a line laser profilometer includes the following steps 210-250.

[0037] Step 210: The computing device 100 can acquire the first contour data of the spherical target collected by the line laser profilometer.

[0038] In some embodiments, the computing device 100 can be communicatively connected to a line laser profilometer. In step 210, the line laser profilometer, located at a first position (i.e., the initial position before the line laser profilometer moves linearly along the linear guide rail), firstly emits a line laser towards the spherical target to acquire first contour data of the spherical target. Subsequently, the line laser profilometer can upload the first contour data of the spherical target it has acquired to the computing device 100, so that the computing device 100 obtains the first contour data of the spherical target acquired by the line laser profilometer. It should be noted that the first contour data is also the first circular contour generated by the intersection of the first laser plane of the line laser profilometer located at the first position and the spherical target. It can be understood that the first circular contour is located on the first laser plane of the line laser profilometer.

[0039] Step 220: The computing device 100 can use a planar circle fitting algorithm to determine the coordinates of the first circle center corresponding to the first contour data.

[0040] Step 230: The computing device 100 can acquire the second contour data of the spherical target collected by the line laser profilometer after moving the target a distance d in a straight line along the linear guide rail.

[0041] In this embodiment of the invention, the position of the spherical target is fixed. The installation angle of the line laser profilometer remains fixed before and after movement, and correspondingly, the laser plane direction of the line laser profilometer remains unchanged.

[0042] In some embodiments, in step 230, the computing device 100 first controls the line laser profilometer to move a target distance d along a linear guide rail, after which the line laser profilometer is positioned at a second position. Subsequently, the line laser profilometer at the second position emits a line laser towards the spherical target to collect the second profile data of the spherical target. The line laser profilometer can upload the collected second profile data of the spherical target to the computing device 100, enabling the computing device 100 to obtain the second profile data of the spherical target collected by the line laser profilometer. It should be noted that the second profile data is the second circular profile generated by the intersection of the second laser plane of the line laser profilometer at the second position and the spherical target. It can be understood that the second circular profile is located on the second laser plane of the line laser profilometer.

[0043] Step 240: The computing device 100 can use a planar circle fitting algorithm to determine the coordinates of the second circle center corresponding to the second contour data.

[0044] Step 250: The calculation device 100 can determine the installation angle error of the line laser profilometer based on the coordinates of the first center, the coordinates of the second center, and the target distance.

[0045] This simplifies the process of calibrating the installation angle error of the line laser profilometer. With simple operation, the angular deviation between the line laser profilometer and the linear guide rail can be accurately calibrated, thereby enabling precise reconstruction of the three-dimensional shape of the target surface.

[0046] In this embodiment of the invention, the installation angle error of the line laser profilometer includes a first installation angle error and a second installation angle error.

[0047] Figure 3 A schematic diagram showing the positional relationship between the line laser profilometer and the linear guide rail direction according to an embodiment of the present invention is shown.

[0048] like Figure 3As shown, in some embodiments, the computing device 100 can establish a line laser profilometer coordinate system (including X-axis, Y-axis, and Z-axis) based on the line laser profilometer located at the first position, which can be represented as (X, Y, Z). Here, the Y-axis direction of the line laser profilometer coordinate system is the laser emission direction of the line laser profilometer, the Z-axis direction is the normal direction of the laser plane (first laser plane) of the line laser profilometer, and the X-axis direction is the direction perpendicular to the Y-axis direction on the laser plane (first laser plane) of the line laser profilometer. That is, the computing device 100 can establish the line laser profilometer coordinate system using the laser emission direction of the line laser profilometer located at the first position as the Y-axis direction, the normal direction of the first laser plane of the line laser profilometer as the Z-axis direction, and the direction perpendicular to the Y-axis direction on the first laser plane of the laser profilometer as the X-axis direction. Additionally, as... Figure 3 As shown, the direction of the linear guide can be represented as V, and it is fixed in the world coordinate system.

[0049] It should be noted that, under ideal conditions where there is no installation angle error in the line laser profilometer, the Z-axis direction of the line laser profilometer is parallel to the direction of the linear guide. The contour data of the target acquired by the line laser profilometer, read along the direction of the linear guide, and then stitched together in the Z-axis direction, can form complete three-dimensional topographic data of the target surface. However, due to machining and installation angle errors of the line laser profilometer, there is an angular deviation between the Z-axis direction (laser emission direction) of the line laser profilometer and the direction of the linear guide. This causes deformation when the contour data of the target acquired by the line laser profilometer is read along the direction of the linear guide and stitched together in the Z-axis direction, which in turn leads to excessive errors or failure in the three-dimensional topographic reconstruction.

[0050] In some embodiments, the mounting angle error of the line laser profilometer includes the mounting angle error of the line laser profilometer about the X-axis (i.e., the first mounting angle error) and the mounting angle error of the line laser profilometer about the Y-axis (i.e., the second mounting angle error). That is, the first mounting angle error is the mounting angle error of the line laser profilometer about the X-axis, and the second mounting angle error is the mounting angle error of the line laser profilometer about the Y-axis.

[0051] Figure 4 A schematic diagram is shown illustrating the calculation of the first mounting angle error of a line laser profilometer about the X-axis according to some embodiments of the present invention. Figure 5 A schematic diagram illustrating the calculation of the second mounting angle error of a line laser profilometer about the Y-axis is shown in some embodiments of the present invention.

[0052] It should be noted that the installation angle of the line laser profilometer remains fixed before and after movement, and the laser plane direction of the line laser profilometer remains unchanged. Therefore, the first laser plane containing the first contour data and the second laser plane containing the second contour data are parallel to each other. Based on this, the straight line passing through the first and second center coordinates is perpendicular to the first and second laser planes of the line laser profilometer. The first center coordinates can be represented as (x1, y1), and the second center coordinates can be represented as (x2, y2).

[0053] like Figure 4 As shown, the linear guide rail direction, the coordinates of the first circle center, and the coordinates of the second circle center are projected onto the YZ plane of the line laser profiler. The angle α between the Z-axis direction and the linear guide rail direction after projection is the first installation angle error of the line laser profiler around the X-axis.

[0054] from Figure 4 It can be seen that the included angle α (the first installation angle error of the line laser profilometer around the X-axis) is in a right triangle with the target distance d moved by the line laser profilometer as the hypotenuse. Therefore, the formula for calculating the included angle α (the first installation angle error) is α=arcsin((y2-y1) / d), where α represents the first installation angle error and d represents the target distance.

[0055] like Figure 5 As shown, the linear guide rail direction, the coordinates of the first circle center, and the coordinates of the second circle center are projected onto the XZ plane of the line laser profiler. The angle β between the Z-axis direction and the linear guide rail direction after projection is the second installation angle error of the line laser profiler around the Y-axis.

[0056] from Figure 5 It can be seen that the included angle β (the second installation angle error of the line laser profilometer around the Y-axis) is in a right triangle with the target distance d moved by the line laser profilometer as the hypotenuse. Therefore, the formula for calculating the included angle β (the second installation angle error) is β=arccos((x2-x1) / d), where β represents the second installation angle error and d represents the target distance.

[0057] That is, in step 250, the first installation angle error α of the line laser profiler around the X-axis and the second installation angle error β of the line laser profiler around the Y-axis can be calculated according to the above formulas α=arcsin((y2-y1) / d) and β=arccos((x2-x1) / d).

[0058] Figure 6 A schematic diagram is shown illustrating the determination of the coordinates of the first center of a circle corresponding to the first contour data using a planar circle fitting algorithm according to some embodiments of the present invention.

[0059] In some embodiments, the process by which the computing device 100 determines the coordinates of the first center of the circle corresponding to the first contour data using a planar circle fitting algorithm in step 220 includes the following steps B1 to B7: B1. Randomly select three first data points from the first contour data that are not on the same straight line. Specifically, firstly, three first data points can be randomly selected from the first contour data, and it is determined whether the three selected first data points are on the same straight line. If they are on the same straight line, then three more first data points are randomly selected from the first contour data again, until the three selected first data points are not on the same straight line; if the three selected first data points are not on the same straight line, then continue to perform the following steps B2 to B7.

[0060] B2. Based on the three extracted first data points (three first data points not on the same straight line), a first plane circle is fitted, and the parameters of the first plane circle fitted by the three extracted first data points are determined. The parameters of the first plane circle include the coordinates of the center of the first plane circle and the radius of the first plane circle.

[0061] B3. Calculate the root mean square error of the difference between the distance from all first data points in the first contour data to the center coordinates of the first plane circle and the radius of the first plane circle.

[0062] B4. Repeat steps B1 to B3 until the predetermined number of executions is reached. Then, select the center coordinates and radius of the first plane circle with the smallest root mean square error, and use them as the first initial center coordinates and the first initial radius R1 (i.e., the parameters of the first initial plane circle), respectively. Based on this, the optimal first initial plane circle can be selected from the multiple first plane circles fitted within the predetermined number of executions.

[0063] B5. Calculate the deviation (L1-R1) between the distance L1 from each first data point in the first contour data to the coordinates of the first initial circle center and the first initial radius R1. Then, calculate the mean and variance of the deviation values ​​of all first data points, that is, calculate the mean and variance of the deviation (L1-R1) between the distance from each first data point in the first contour data to the coordinates of the first initial circle center and the first initial radius.

[0064] B6. Remove all first data points in the first contour data whose difference between the deviation value and the mean deviation value is greater than three times the variance of the deviation value, to obtain the first initial contour data (the remaining and unremoved first data points in the first contour data constitute the first initial contour data).

[0065] B7. Based on the first initial contour data, the first initial circle center coordinates, and the first initial radius, the first target plane circle is obtained by fitting using the least squares method. Then, the circle center coordinates of the first target plane circle can be determined, and the circle center coordinates of the first target plane circle can be used as the first circle center coordinates corresponding to the first contour data.

[0066] Similarly, in step 240, the process by which the computing device 100 determines the coordinates of the second center of the second contour data using a planar circle fitting algorithm includes the following steps D1~D7: D1. Randomly select three second data points from the second contour data that are not on the same straight line. Specifically, first, three second data points can be randomly selected from the second contour data, and it is determined whether the three selected second data points are on the same straight line. If they are on the same straight line, then three more second data points are randomly selected from the second contour data again, until the three selected second data points are not on the same straight line; if the three selected second data points are not on the same straight line, then continue to perform the following steps D2~D7.

[0067] D2. Based on the three extracted second data points (three second data points not on the same straight line), fit the second plane circle and determine the parameters of the second plane circle fitted by the three extracted second data points. The parameters of the second plane circle include the coordinates of the center of the second plane circle and the radius of the second plane circle.

[0068] D3. Calculate the root mean square error of the difference between the distance from all second data points in the second contour data to the center coordinates of the second plane circle and the radius of the second plane circle.

[0069] D4. Repeat steps D1 to D3 until the predetermined number of executions is reached. Then, select the coordinates of the center of the second plane circle with the smallest root mean square error and the radius of the second plane circle as the coordinates of the second initial circle center and the second initial radius R2 (i.e., the parameters of the second initial plane circle), respectively. Based on this, the optimal second initial plane circle can be selected from the multiple second plane circles fitted in the predetermined number of executions.

[0070] D5. Calculate the deviation (L2-R2) between the distance L2 from each second data point in the second contour data to the coordinates of the second initial circle center and the second initial radius. Then, calculate the mean and variance of the deviation values ​​of all second data points, that is, calculate the mean and variance of the deviation (L2-R2) between the distance from each second data point in the second contour data to the coordinates of the second initial circle center and the second initial radius.

[0071] D6. Remove all second data points in the second contour data whose difference between the deviation value and the mean deviation value is greater than three times the variance of the deviation value, to obtain the second initial contour data (the remaining, unremoved second data points in the second contour data constitute the second initial contour data).

[0072] D7. Based on the second initial contour data, the second initial circle center coordinates, and the second initial radius, the second target plane circle is obtained by fitting using the least squares method. Then, the center coordinates of the second target plane circle can be determined, and the center coordinates of the second target plane circle can be used as the second circle center coordinates corresponding to the second contour data.

[0073] Figure 7 A schematic diagram of a line laser profilometer mounting angle error calibration device 700 according to an embodiment of the present invention is shown. The line laser profilometer mounting angle error calibration device 700 can be deployed in a computing device 100, and the line laser profilometer mounting angle error calibration device 700 is configured to perform the line laser profilometer mounting angle error calibration method 200 of the present invention.

[0074] like Figure 7 As shown, in an embodiment of the present invention, the line laser profilometer mounting angle error calibration device 700 includes a first acquisition module 710, a first determination module 720, a second acquisition module 730, a second determination module 740, and an error determination module 750 that are sequentially connected in communication.

[0075] The first acquisition module 710 can acquire the first contour data of the spherical target collected by the line laser profilometer.

[0076] The first determining module 720 can use a planar circle fitting algorithm to determine the coordinates of the first circle center corresponding to the first contour data.

[0077] The second acquisition module 730 can acquire the second contour data of the spherical target collected by the line laser profilometer after moving the target distance linearly along the linear guide rail.

[0078] The second determining module 740 can use a planar circle fitting algorithm to determine the coordinates of the second circle center corresponding to the second contour data.

[0079] The error determination module 750 can determine the installation angle error of the line laser profilometer based on the coordinates of the first center, the coordinates of the second center, and the target distance.

[0080] It should be noted that the first acquisition module 710, the first determination module 720, the second acquisition module 730, the second determination module 740, and the error determination module 750 are respectively used to execute the aforementioned steps 210 to 250. Here, the specific execution logic of each unit can be found in the description of steps 210 to 250 in the previous method 200, and will not be repeated here.

[0081] According to the line laser profilometer installation angle error calibration method 200 of this embodiment, the method acquires first contour data of a spherical target collected by the line laser profilometer, determines the first center coordinates of the circle corresponding to the first contour data using a planar circle fitting algorithm, then acquires second contour data of the spherical target collected by the line laser profilometer after moving it linearly along a linear guide rail for a target distance, determines the second center coordinates of the circle corresponding to the second contour data using a planar circle fitting algorithm, and finally determines the installation angle error of the line laser profilometer based on the first center coordinates, the second center coordinates, and the target distance. This simplifies the line laser profilometer installation angle error calibration process, reduces calibration costs, and thus improves the versatility of the line laser profilometer installation angle error calibration.

[0082] The various techniques described herein can be implemented in combination with hardware or software, or a combination thereof. Thus, the methods and apparatus of the present invention, or certain aspects or portions thereof, can take the form of program code (i.e., instructions) embedded in a tangible medium, such as a removable hard disk, USB flash drive, floppy disk, CD-ROM, or any other machine-readable storage medium, wherein when the program is loaded into and executed by a machine such as a computer, the machine becomes an apparatus for practicing the present invention.

[0083] When the program code is executed on a programmable computer, the mobile terminal generally includes a processor, a processor-readable storage medium (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device. The memory is configured to store program code; the processor is configured to execute the line laser profilometer mounting angle error calibration method of the present invention according to instructions in the program code stored in the memory.

[0084] By way of example, and not limitation, readable media include readable storage media and communication media. Readable storage media stores information such as computer-readable instructions, data structures, program modules, or other data. Communication media generally embodies computer-readable instructions, data structures, program modules, or other data in the form of modulated data signals such as carrier waves or other transmission mechanisms, and includes any information delivery medium. Any combination of the above is also included within the scope of readable media.

[0085] In the specification provided herein, the algorithms and displays are not inherently related to any particular computer, virtual system, or other device. Various general-purpose systems can also be used with the examples of this invention. The required structure for constructing such systems is apparent from the above description. Furthermore, this invention is not directed to any particular programming language. It should be understood that the contents of the invention described herein can be implemented using various programming languages, and the above description of specific languages ​​is for the purpose of disclosing the best mode of implementation of the invention.

[0086] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0087] Similarly, it should be understood that, in order to streamline this disclosure and aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof.

[0088] Those skilled in the art will understand that modules, units, or components of the devices disclosed in the examples herein can be arranged in the devices described in this embodiment, or alternatively, can be located in one or more devices different from the devices in this example. The modules in the foregoing examples can be combined into a single module or, in addition, can be divided into multiple sub-modules.

[0089] Unless otherwise specified, the use of ordinal numbers such as “first,” “second,” “third,” etc., to describe ordinary objects merely indicates different instances of similar objects and is not intended to imply that the objects being described must have a given order in time, space, ordering, or any other manner.

Claims

1. A method for calibrating the installation angle error of a line laser profilometer, executed in a computing device, wherein the installation angle error of the line laser profilometer is the angular deviation between the line laser profilometer and the direction of the linear guide rail, the method comprising: Acquire the first contour data of the spherical target collected by the line laser profilometer; The coordinates of the first circle center corresponding to the first contour data are determined using a planar circle fitting algorithm. Acquire the second contour data of the spherical target after the line laser profilometer has moved the target a distance in a straight line along the linear guide rail; The coordinates of the second circle center corresponding to the second contour data are determined using a planar circle fitting algorithm. The installation angle error of the line laser profilometer is determined based on the coordinates of the first center of the circle, the coordinates of the second center of the circle, and the target distance.

2. The method of claim 1, wherein, Acquiring the first contour data of the spherical target collected by the line laser profilometer includes: The line laser profilometer located at the first position emits a line laser towards the spherical target to collect the first contour data of the spherical target. The first contour data is the first circular contour generated by the intersection of the first laser plane of the line laser profilometer located at the first position and the spherical target. The first contour data of the spherical target collected by the line laser profilometer is obtained.

3. The method of claim 2, wherein, Acquiring the second contour data of the spherical target, collected by the line laser profilometer after it has moved the target a distance in a straight line along the linear guide rail, includes: The line laser profilometer is controlled to move linearly along the linear guide rail a target distance so that the line laser profilometer is located in the second position. A line laser is emitted towards the spherical target using a line laser profilometer located at the second position to collect the second contour data of the spherical target. The second contour data is the second circular contour generated by the intersection of the second laser plane of the line laser profilometer located at the second position and the spherical target. The second contour data of the spherical target collected by the line laser profilometer is obtained.

4. The method of claim 3, wherein, The straight line passing through the first center coordinate and the second center coordinate is perpendicular to the first laser plane and the second laser plane; the first center coordinate is represented as (x1, y1), and the second center coordinate is represented as (x2, y2); the installation angle error of the line laser profilometer includes a first installation angle error and a second installation angle error; Based on the coordinates of the first center of the circle, the coordinates of the second center of the circle, and the target distance, the installation angle error of the line laser profilometer is determined, including: The first installation angle error and the second installation angle error are calculated using the following formulas: α = arcsin((y2-y1) / d); β=arccos((x2-x1) / d); Where α represents the first installation angle error, β represents the second installation angle error, and d represents the target distance.

5. The method of claim 4, wherein, Also includes: A coordinate system for the line laser profilometer is established by taking the laser emission direction of the line laser profilometer located at the first position as the Y-axis direction, the normal direction of the first laser plane of the line laser profilometer as the Z-axis direction, and the direction perpendicular to the Y-axis direction on the first laser plane of the laser profilometer as the X-axis direction. Wherein, the first installation angle error is the installation angle error of the line laser profilometer around the X-axis, and the second installation angle error is the installation angle error of the line laser profilometer around the Y-axis.

6. The method of any one of claims 1-5, wherein, The coordinates of the first circle center corresponding to the first contour data are determined using a planar circle fitting algorithm, including the following steps: Three first data points that are not on the same straight line are randomly selected from the first contour data; Determine the first planar circle parameters fitted to the three first data points, wherein the first planar circle parameters include the coordinates of the center of the first planar circle and the radius of the first planar circle; Calculate the root mean square error of the difference between the distance from all first data points in the first contour data to the center coordinates of the first plane circle and the radius of the first plane circle; Repeat the above steps until the predetermined number of executions is reached. Then, select the center coordinates and radius of the first plane circle with the smallest root mean square error as the first initial center coordinates and the first initial radius, respectively. Calculate the deviation between the distance from each first data point in the first contour data to the coordinates of the first initial circle center and the first initial radius, and calculate the mean and variance of the deviation values ​​of all first data points. First data points in the first contour data whose difference between the deviation value and the mean of the deviation value is greater than three times the variance of the deviation value are removed to obtain the first initial contour data. Based on the first initial contour data, the first initial circle center coordinates, and the first initial radius, the first target plane circle is obtained by fitting using the least squares method, and the circle center coordinates of the first target plane circle are determined as the first circle center coordinates corresponding to the first contour data.

7. The method of any one of claims 1-6, wherein, The coordinates of the second circle center corresponding to the second contour data are determined using a planar circle fitting algorithm, including the following steps: Three second data points that are not on the same straight line are randomly selected from the second contour data; Determine the second plane circle parameters fitted to the three second data points, wherein the second plane circle parameters include the coordinates of the center of the second plane circle and the radius of the second plane circle; Calculate the root mean square error of the difference between the distance from all second data points in the second contour data to the center coordinates of the second plane circle and the radius of the second plane circle; Repeat the above steps until the predetermined number of executions is reached. Then, select the coordinates of the center of the second plane circle with the smallest root mean square error and the radius of the second plane circle as the second initial center coordinates and the second initial radius, respectively. Calculate the deviation between the distance from each second data point in the second contour data to the coordinates of the second initial circle center and the second initial radius, and calculate the mean and variance of the deviation values ​​of all second data points; Remove all second data points in the second contour data whose difference between the deviation value and the mean of the deviation value is greater than three times the variance of the deviation value, so as to obtain the second initial contour data. Based on the second initialized contour data, the second initialized circle center coordinates, and the second initialized radius, the second target plane circle is obtained by fitting using the least squares method, and the circle center coordinates of the second target plane circle are determined as the second circle center coordinates corresponding to the second contour data.

8. A calibration device for the installation angle error of a line laser profilometer, deployed in a computing device, suitable for performing the method as described in any one of claims 1-7, wherein the installation angle error of the line laser profilometer is the angular deviation between the line laser profilometer and the direction of the linear guide rail, the device comprising: The first acquisition module is adapted to acquire the first contour data of the spherical target collected by the line laser profilometer; The first determining module is adapted to use a planar circle fitting algorithm to determine the coordinates of the first circle center corresponding to the first contour data; The second acquisition module is adapted to acquire the second contour data of the spherical target after the line laser profilometer moves the target distance in a straight line along the linear guide rail; The second determining module is adapted to use a planar circle fitting algorithm to determine the coordinates of the second circle center corresponding to the second contour data; The error determination module is adapted to determine the installation angle error of the line laser profilometer based on the first center coordinates, the second center coordinates, and the target distance.

9. A computing device, comprising: At least one processor; and A memory storing program instructions, wherein the program instructions are configured to be processed by the at least one processor, the program instructions including instructions for processing the method as described in any one of claims 1-7.

10. A computer program product comprising computer program instructions, wherein, When the computer program instructions are executed by the processor, they implement the method as described in any one of claims 1-7.

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