Laser displacement sensor calibration method and device, storage medium and electronic equipment

Abstract

Embodiments of the present application disclose a laser displacement sensor calibration method and device, a storage medium and an electronic device, and relate to the technical field of sensor measurement. The method comprises: constructing a matrix equation according to auxiliary parameters and a plurality of first plane equations; deleting any row elements of an augmented matrix and returning to the step of constructing the matrix equation according to the auxiliary parameters and the plurality of first plane equations until the matrix equation meets an accuracy condition to obtain a target matrix equation; and obtaining target measurement parameters of a target sensor according to the target matrix equation to complete calibration. The present application uses auxiliary parameters to construct a matrix equation for solving, continuously attempts to delete some data in a loop process to control the error of matrix solving, and the establishment of the matrix equation is derived from the measurement parameters of the target sensor and the thickness parameters of the calibration plate. In the optimization process, the influence of the plane measurement accuracy and the sensor itself error can be effectively reduced, and the quality of the sensor calibration method is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensor measurement, in particular to a laser displacement sensor calibration method and device, a storage medium and an electronic device. BACKGROUND

[0002] The laser displacement sensor is a non-contact distance measuring sensor, which is widely used in the industrial field and also has important application in the field of aircraft assembly, and is mainly used for normal alignment of digital hole-making tool heads. In order to realize the normal vector alignment function, it is necessary to determine the measurement starting point coordinates and the measurement direction vector of each laser displacement sensor in the same coordinate system, that is, to calibrate the measurement parameters thereof.

[0003] Currently, a plane calibration method is usually used, but this method has the following problems: the calibration calculation is easily affected by the plane measurement accuracy of the calibration plate and the sensor error, and the method itself does not have corresponding compensation measures, resulting in poor quality of the existing calibration method. SUMMARY

[0004] The main purpose of the present application is to provide a laser displacement sensor calibration method and device, a storage medium and an electronic device, which aims to solve the problem of poor quality of the existing laser displacement sensor calibration method.

[0005] To achieve the above purpose, the technical solutions adopted by the embodiments of the present application are as follows:

[0006] In a first aspect, the embodiments of the present application provide a laser displacement sensor calibration method, comprising the following steps:

[0007] According to the auxiliary parameters and the plurality of first plane equations, a matrix equation is constructed; wherein the auxiliary parameters include: the measurement parameters of the target sensor, the thickness parameters of the calibration plate and the return parameters obtained by the target sensor emitting laser to the calibration plate, the plurality of first plane equations are obtained under different postures of the calibration plate, and the matrix equation is established based on a coefficient matrix, a parameter matrix and an augmented matrix;

[0008] Any row element of the augmented matrix is deleted, and the step of constructing the matrix equation according to the auxiliary parameters and the plurality of first plane equations is returned, until the matrix equation meets the accuracy condition, and a target matrix equation is obtained;

[0009] According to the target matrix equation, the target measurement parameters of the target sensor are obtained to complete the calibration.

[0010] In a possible implementation manner of the first aspect, the step of constructing the matrix equation according to the auxiliary parameters and the plurality of first plane equations comprises:

[0011] According to the measurement parameter of the target sensor, the thickness parameter of the calibration plate, the return parameter, and the first plane equation, a simultaneous equation is obtained;

[0012] According to the simultaneous equation, a coefficient matrix, a parameter matrix, and an augmented matrix are obtained;

[0013] According to the coefficient matrix, the parameter matrix, and the augmented matrix, a matrix equation is constructed.

[0014] In a possible implementation manner of the first aspect, the plane corresponding to the first plane equation is the first face of the calibration plate, and the first face of the calibration plate is the face that receives the laser emitted by the target sensor. Before the matrix equation is constructed according to the auxiliary parameter and the first plane equation, the laser displacement sensor calibration method further includes:

[0015] According to the second plane equation and the thickness parameter of the calibration plate, a first plane equation is obtained; wherein the plane corresponding to the second plane equation is the second face of the calibration plate, and the second face of the calibration plate is the face away from the first face.

[0016] In a possible implementation manner of the first aspect, before the first plane equation is obtained according to the second plane equation and the thickness parameter of the calibration plate, the laser displacement sensor calibration method further includes:

[0017] Obtain three-dimensional point cloud data of the second face of the calibration plate under different postures of the calibration plate;

[0018] The three-dimensional point cloud data under different postures are respectively fitted to obtain a second plane equation.

[0019] In a possible implementation manner of the first aspect, obtaining the three-dimensional point cloud data of the second face of the calibration plate under different postures of the calibration plate includes:

[0020] Obtain a fringe projection image of the second face of the calibration plate under different postures of the calibration plate;

[0021] The fringe projection image is phase-unwrapped to obtain the three-dimensional point cloud data of the second face of the calibration plate.

[0022] In a possible implementation manner of the first aspect, any row element of the augmented matrix is deleted, and the step of constructing the matrix equation according to the measurement parameter of the target sensor and the first plane equation is returned until the matrix equation meets the accuracy condition, to obtain a target matrix equation, including:

[0023] Any row element of the augmented matrix is deleted, and the step of constructing the matrix equation according to the measurement parameter of the target sensor and the first plane equation is returned;

[0024] The parameter matrix is solved to obtain a predicted thickness of the calibration plate;

[0025] In a case where the thickness difference between the predicted thickness of the calibration plate and the real thickness of the calibration plate is getting smaller, return to the step of deleting any row element of the augmented matrix and constructing the matrix equation according to the measurement parameter of the target sensor and the first plane equation until the matrix equation satisfies the accuracy condition to obtain the target matrix equation.

[0026] In a possible implementation of the first aspect, before the case where the thickness difference between the predicted thickness of the calibration plate and the real thickness of the calibration plate is getting smaller, the laser displacement sensor calibration method further includes:

[0027] judging the change of the thickness difference.

[0028] In a possible implementation of the first aspect, in a case where the judgment result of the change of the thickness difference is not getting smaller, performing:

[0029] complementing the deleted element of the augmented matrix back to the augmented matrix, and returning to the step of deleting any row element of the augmented matrix and constructing the matrix equation according to the measurement parameter of the target sensor and the first plane equation.

[0030] In a possible implementation of the first aspect, the accuracy condition includes that the deleted element of the augmented matrix reaches a target row number or the thickness difference is not greater than a preset value.

[0031] In a second aspect, an embodiment of the present application provides a laser displacement sensor calibration device, including:

[0032] a construction module, the construction module being configured to construct a matrix equation according to auxiliary parameters and a plurality of first plane equations; the auxiliary parameters include a measurement parameter of a target sensor, a thickness parameter of a calibration plate, and a return parameter obtained by the target sensor emitting laser to the calibration plate, the plurality of first plane equations are obtained in different postures of the calibration plate, and the matrix equation is established based on a coefficient matrix, a parameter matrix, and an augmented matrix;

[0033] a loop module, the loop module being configured to delete any row element of the augmented matrix and return to the step of constructing the matrix equation according to the auxiliary parameters and the plurality of first plane equations until the matrix equation satisfies an accuracy condition to obtain a target matrix equation;

[0034] a solution module, the solution module being configured to obtain a target measurement parameter of the target sensor according to the target matrix equation to complete calibration.

[0035] In a third aspect, an embodiment of the present application provides a computer readable storage medium storing a computer program, and the computer program is loaded and executed by a processor to implement the laser displacement sensor calibration method provided in any one of the above first aspects.

[0036] In a fourth aspect, an electronic device is provided, comprising a processor and a memory, wherein,

[0037] The memory is configured to store a computer program;

[0038] The processor is configured to load and execute the computer program, so that the electronic device performs the laser displacement sensor calibration method provided in any one of the above first aspect.

[0039] Compared with the prior art, the present application has the following beneficial effects:

[0040] The laser displacement sensor calibration method, device, storage medium and electronic device provided by the embodiments of the present application comprise the following steps: a matrix equation is constructed according to auxiliary parameters and a plurality of first plane equations; the auxiliary parameters comprise a measurement parameter of a target sensor, a thickness parameter of a calibration plate and a return parameter obtained by the target sensor emitting laser to the calibration plate, the plurality of first plane equations are obtained under different postures of the calibration plate, and the matrix equation is established based on a coefficient matrix, a parameter matrix and an augmented matrix; any row element of the augmented matrix is deleted, and the step of constructing the matrix equation according to the auxiliary parameters and the plurality of first plane equations is returned until the matrix equation meets an accuracy condition to obtain a target matrix equation; and a target measurement parameter of the target sensor is obtained according to the target matrix equation to complete calibration. The method of the present application uses the auxiliary parameters to construct the matrix equation for solving, and the related data obtained under different postures of the calibration plate makes the final solving result universal, and improves the accuracy of calibration. Since some data is continuously tried to be deleted in the loop process to control the error of matrix solving, and the matrix equation is established based on the measurement parameter of the target sensor and the thickness parameter of the calibration plate, the influence of plane measurement accuracy and sensor self-error can be effectively reduced in the optimization process, and then the optimal matrix equation meeting the accuracy condition is obtained, the target sensor parameter with high accuracy is quickly obtained through solving of the target matrix equation to complete calibration, and the quality of the method for calibrating the sensor is improved. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 An electronic device structure schematic diagram of a hardware running environment related to the embodiments of the present application;

[0042] Figure 2 A flowchart of the laser displacement sensor calibration method provided by the embodiments of the present application;

[0043] Figure 3 An application scenario schematic diagram of the laser displacement sensor calibration method provided by the embodiments of the present application;

[0044] Figure 4A module schematic diagram of the laser displacement sensor calibration device provided by the embodiment of the application is shown in the figure.

[0045] Marked in the figure: 101-processor, 102-communication bus, 103-network interface, 104-user interface, 105-memory; 1-laser displacement sensor, 2-calibration plate, 3-industrial camera, 4-projector, 5-moving clamp. DETAILED DESCRIPTION

[0046] It should be understood that the specific embodiments described herein are merely intended to explain the application and are not intended to limit the application.

[0047] The main solution of the embodiment of the application is to propose a laser displacement sensor calibration method, device, storage medium and electronic equipment, the method comprising: constructing a matrix equation according to auxiliary parameters and a plurality of first plane equations; wherein the auxiliary parameters comprise: a measurement parameter of a target sensor, a thickness parameter of a calibration plate, and a return parameter obtained by the target sensor emitting laser to the calibration plate, the plurality of first plane equations are obtained under different postures of the calibration plate, and the matrix equation is established based on a coefficient matrix, a parameter matrix and an augmented matrix; deleting any row elements of the augmented matrix, and returning to the step of constructing the matrix equation according to the auxiliary parameters and the plurality of first plane equations, until the matrix equation meets the accuracy condition, and obtaining a target matrix equation; obtaining a target measurement parameter of the target sensor according to the target matrix equation, so as to complete the calibration.

[0048] The laser displacement sensor is a non-contact distance measuring sensor, which is widely used in the industrial field and also has important application in the field of aircraft assembly, and is mainly used for normal alignment of a digital hole-making tool head. When used for normal alignment of the digital hole-making tool head, the laser displacement sensor is generally used in groups of four, the distance of a surface to be drilled relative to the four sensors is measured, the angle of the surface to be drilled relative to the tool head is calculated, and the normal vector correction basis is provided for the digital hole-making equipment, so that the digital hole-making tool head can drill holes perpendicular to the surface to be drilled.

[0049] In order to realize the normal vector alignment function, it is necessary to determine the measurement starting point coordinates and the measurement direction vector of each laser displacement sensor in the same coordinate system. In order to determine the above parameters, a plane calibration method is usually used, that is, a plane is placed in the measurement range of the sensor, the plane is measured by a laser tracker and other equipment, the plane equation is obtained, the unknowns are substituted, and the equation group is constructed for solving.

[0050] However, the above method has the following problems: 1. The plane measurement equipment and the laser displacement sensor measure the same surface, the operating space is limited, and there is interference between the physical devices. In order to achieve calibration, the plane area needs to be increased, which requires the processing of a larger calibration plate; 2. The calibration calculation is easily affected by the plane measurement accuracy and sensor error, and the above method does not have the function of reducing or eliminating this influence; 3. The accuracy of the calibration result cannot be verified.

[0051] To this end, the present application provides a solution, which uses auxiliary parameters to construct a matrix equation for solution, and obtains relevant data under different postures of the calibration plate, so that the final solution result can be universal, thereby improving the accuracy of calibration. Since some data are continuously deleted during the loop process to control the error of the matrix solution, and the establishment of the matrix equation is based on the measurement parameters of the target sensor and the thickness parameters of the calibration plate, it can effectively reduce the influence of the plane measurement accuracy and the sensor's own error during the optimization process, and then obtain the optimal matrix equation that meets the accuracy conditions. By solving the target matrix equation, the target sensor parameters with higher accuracy can be quickly obtained to complete the calibration, thereby improving the quality of the method for calibrating the sensor.

[0052] Refer to the attached Figure 1 , attached Figure 1 This is a schematic diagram of the structure of an electronic device of the hardware operating environment involved in the embodiment of the present application. The electronic device may include: a processor 101, such as a central processing unit (CPU), a communication bus 102, a user interface 104, a network interface 103, and a memory 105. Among them, the communication bus 102 is used to realize the connection and communication between these components. The user interface 104 may include a display screen (Display), an input unit such as a keyboard (Keyboard), and the user interface 104 may also include a standard wired interface and a wireless interface. The network interface 103 may optionally include a standard wired interface and a wireless interface (such as a wireless fidelity (WIreless-FIdelity, WI-FI) interface). The memory 105 may optionally be a storage device independent of the aforementioned processor 101. The memory 105 may be a high-speed random access memory (RAM) memory, or a stable non-volatile memory (NVM), such as at least one disk memory. The processor 101 may be a general-purpose processor, including a central processing unit, a network processor, etc., or may be a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component.

[0053] Those skilled in the art will understand thatFigure 1 The structure shown in the figure does not constitute a limitation on the electronic device, and can include more or fewer components than shown, or combine certain components, or different component arrangements.

[0054] As shown in the accompanying Figure 1 The memory 105 as a storage medium can include an operating system, a data storage module, a network communication module, a user interface module, and an electronic program.

[0055] As shown in the accompanying Figure 1 In the electronic device shown in the figure, the network interface 103 is mainly used for data communication with the network server; the user interface 104 is mainly used for data interaction with the user; the processor 101 and the memory 105 in the present application can be arranged in the electronic device, and the electronic device calls the laser displacement sensor calibration device stored in the memory 105 through the processor 101, and executes the laser displacement sensor calibration method provided by the present application.

[0056] Referring to the accompanying Figure 2 , based on the hardware device of the foregoing embodiment, the embodiment of the present application provides a laser displacement sensor calibration method, comprising the following steps:

[0057] S10: Constructing a matrix equation according to the auxiliary parameters and a plurality of first plane equations; wherein the auxiliary parameters include: the measurement parameters of the target sensor, the thickness parameters of the calibration plate, and the return parameters obtained by the target sensor emitting laser to the calibration plate, the plurality of first plane equations are obtained under different postures of the calibration plate, and the matrix equation is established based on a coefficient matrix, a parameter matrix and an augmented matrix.

[0058] In the specific implementation process, the target sensor is a laser displacement sensor that needs to be calibrated, the calibration plate is a flat plate with front and back surfaces set by using the plane calibration method, and the auxiliary parameters are parameters used to establish the matrix equation. Since the measurement parameters of the target sensor need to be solved and calibrated, the specific value of the parameters does not need to be known when establishing the matrix equation, that is, the parameters are assumed first, such as the measurement parameters of the laser displacement sensor including the measurement starting point coordinates, that is, the zero point coordinates (x, y, z), and the measurement direction vector of the laser displacement sensor, that is, the direction vector (l, m, n) of the emitted laser beam. Since it is also necessary to reduce the influence of the thickness of the calibration plate, the thickness parameter d of the calibration plate is introduced, and the true value of d is known according to the selected calibration plate. In the embodiment of the present application, the predicted value of d is used to compare with the true value to quantify the error size.

[0059] The return parameter is the value of the light reflected by the laser beam emitted by the transmitting end of the laser displacement sensor 1 after it hits the calibration plate 2 and is fed back by the receiving end of the laser displacement sensor 1. This value can reflect the distance measurement situation and is usually expressed by the feedback voltage value V. Figure 3 In the application scenario shown, the laser beam emitted by the laser displacement sensor 1 is the solid line at the top, and the reflected laser beam is the dotted line at the bottom. The calibration plate 2 is clamped by a movable clamp 5, and the clamp can be adjusted to change different postures.

[0060] The first plane equation is the equation that characterizes the first surface of the calibration plate 2, that is, the surface that receives the laser beam. Figure 3 The front side of the calibration plate 2 shown in the figure is denoted as Z side, and the second side of the calibration plate 2, i.e., its back side, is denoted as F side. Since the data is acquired multiple times in different postures, the number of data acquisitions is represented by i, i.e., the equation of the first plane obtained by the i-th acquisition is The return parameter is the voltage value V returned by the laser displacement sensor 1 i Since the first surface is parallel to the second surface, the second plane equation A corresponding to the second surface can be used. i x+B i y+C i z+D i =0 is obtained by combining the thickness value d, that is, the plane corresponding to the first plane equation is the first surface of the calibration plate, and the first surface of the calibration plate is the side that receives the laser emitted by the target sensor. Before constructing the matrix equation based on the auxiliary parameters and the first plane equations, the laser displacement sensor calibration method also includes:

[0061] According to the second plane equations and the thickness parameter of the calibration plate, the first plane equations are obtained; wherein the plane corresponding to the second plane equation is the second surface of the calibration plate, and the second surface of the calibration plate is the surface away from the first surface.

[0062] The multiple times in this embodiment is more than 100 times, that is, at least 100 sets of first plane equations and corresponding return parameters need to be collected.

[0063] S101: obtaining simultaneous equations according to measurement parameters of the target sensor, thickness parameters of the calibration plate, return parameters, and a plurality of first plane equations;

[0064] S102: Obtain a coefficient matrix, a parameter matrix, and an augmented matrix according to the simultaneous equations;

[0065] S103: Construct a matrix equation based on the coefficient matrix, the parameter matrix, and the augmented matrix.

[0066] In the implementation process, since the expressions of the obtained parameters are all the same, in order to combine multiple groups of data, a matrix method is used for deformation, wherein the first plane equation corresponding to the first surface of the calibration plate 2 is denoted as The return parameter is V i The coordinates of the point measured by the sensor represented by (x, y, z, l, m, n) on the first surface are (x+lV i , y+mV i , z+nV i ), and substituting it into the first plane equation can obtain the simultaneous equations as follows:

[0067]

[0068] That is:

[0069]

[0070] · [x y z l m n d] T = -D i

[0071] Therefore, the matrix equation Er=b can be determined, wherein E is a coefficient matrix:

[0072]

[0073] r is a parameter matrix:

[0074] r = [x y z l m n d] T

[0075] [E|b] is an augmented matrix, so b can be obtained as:

[0076] b = [-D1…-D i …-D 100 ] T

[0077] In an embodiment, before obtaining a plurality of first plane equations according to a plurality of second plane equations and a thickness parameter of the calibration plate, the laser displacement sensor calibration method further comprises:

[0078] obtaining three-dimensional point cloud data on the second surface of the calibration plate in different postures of the calibration plate;

[0079] obtaining three-dimensional point cloud data on the second surface of the calibration plate in different postures of the calibration plate, comprising:

[0080] obtaining a grating projection image on the second surface of the calibration plate in different postures of the calibration plate;

[0081] phase unwrapping the grating projection image to obtain three-dimensional point cloud data on the second surface of the calibration plate.

[0082] In the implementation process, in order to save the operation space, the calibration method of the application is carried out from different surfaces of the calibration plate 2, the grating projection image projected on the second surface of the calibration plate is changed by changing the posture, and the phase is solved and unfolded by synchronously shooting with the industrial camera while capturing the projection image, and the three-dimensional point cloud data on the second surface is obtained.

[0083] The three-dimensional point cloud data under different postures are respectively fitted with a plane, and a plurality of second plane equations are obtained.

[0084] In the implementation process, in order to realize the obtaining of the plane, a plurality of sets of three-dimensional point cloud data are respectively fitted by adopting a plane fitting mode, that is, a virtual plane is constructed, so that as many points as possible are located on the same plane, and a plurality of fitted planes are obtained. The plane is expressed by an equation A i x+B i y+C i z+D i =0, that is, the second plane equation.

[0085] S20: deleting any row elements of the augmented matrix, and returning to the step of constructing the matrix equation according to the auxiliary parameters and the plurality of first plane equations, until the matrix equation meets the accuracy condition, and obtaining the target matrix equation.

[0086] In the implementation process, the augmented matrix is a column element added to the right side of the coefficient matrix, and the element is the value on the right side of the equation group. In order to realize the control of the solving error, the elements of a row of the augmented matrix are deleted, that is, a group of equations and their solving values are deleted, and then it is determined whether the deleted values have an influence on the solving accuracy by the judging mode provided in the application embodiment. Specifically:

[0087] Step S20: deleting any row elements of the augmented matrix, and returning to the step of constructing the matrix equation according to the measurement parameters of the target sensor and the first plane equation, until the matrix equation meets the accuracy condition, and obtaining the target matrix equation, comprising:

[0088] S201: deleting any row elements of the augmented matrix, and returning to the step of constructing the matrix equation according to the measurement parameters of the target sensor and the first plane equation;

[0089] S202: solving the parameter matrix to obtain the predicted thickness of the calibration plate;

[0090] In the implementation process, a row of elements is first deleted in a loop, then the step of constructing a matrix equation according to the measurement parameters of the target sensor and the first plane equation is returned, the matrix equation is updated, and then the parameter matrix corresponding to the updated matrix equation is solved to obtain a set of predicted thicknesses of the calibration plate. The solution can be obtained by using the least square method, r = (E T E) -1 E T b, wherein T all represent transposition, the value of d, that is, the predicted thickness, can be obtained from r, and the difference between the real thickness and the predicted thickness can be calculated to obtain the thickness difference, that is, the thickness difference Δ = |0.65-d|.

[0091] S203: judging the change of the thickness difference.

[0092] S204: in the case where the thickness difference between the predicted thickness of the calibration plate and the real thickness of the calibration plate is reduced, returning to the step of deleting any row element of the augmented matrix and returning to the step of constructing a matrix equation according to the measurement parameters of the target sensor and the first plane equation until the matrix equation meets the accuracy condition to obtain the target matrix equation.

[0093] In the implementation process, since it is not constantly updated in a loop, a plurality of thickness differences can be obtained, and the change condition is that whether the thickness difference obtained for the i-th time is smaller than Δi-1, that is, Δi. If the thickness difference is reduced, it indicates that the deleted element can optimize to improve the calibration accuracy, in which case the deletion is maintained, and the foregoing step is returned to continue the loop to update and optimize the matrix equation.

[0094] If the judgment result of judging the change of the thickness difference is not reduced, the following is performed:

[0095] The deleted element of the augmented matrix is supplemented back to the augmented matrix, and the step of deleting any row element of the augmented matrix and returning to the step of constructing a matrix equation according to the measurement parameters of the target sensor and the first plane equation is returned.

[0096] In the implementation process, if the thickness difference is not reduced, it indicates that the deleted element will more affect the calibration accuracy, in which case the deletion needs to be cancelled, the deleted element is supplemented back to the augmented matrix, and then the foregoing step is returned to delete another row element again for solving.

[0097] On the basis of the above-mentioned embodiment, in order to realize the automatic stop of the loop process, a termination condition of the loop is set, that is, a precision condition. The loop terminates when the matrix equation meets the precision condition. The precision condition can be determined by the number of valid cycles. A valid cycle means that the elements of the augmented matrix can be deleted and will not be revoked during this cycle. The precision condition at this time is that the deleted elements of the augmented matrix reach the target number of rows. In the embodiment of the present application, when the number of data groups is more than 100, the target number of rows is set to 15 rows, that is, when 15 rows of elements are successfully deleted, it is determined that the matrix equation meets the precision condition and the loop terminates. Since there is a thickness difference to quantify the error, the precision condition can be set to the thickness difference Δ not greater than the preset value. In this application, the preset value can be set to 0.01, that is, when Δ≤0.01, it is confirmed that the matrix equation meets the precision condition and the loop terminates.

[0098] S30: According to the target matrix equation, the target measurement parameters of the target sensor are obtained to complete the calibration.

[0099] In the specific implementation process, after controlling the solution error, the matrix equation obtained is the optimal equation, that is, the target matrix equation. In the aforementioned embodiment, since some elements may have been deleted, the data collected at the corresponding times no longer exists. Therefore, it is only necessary to use the remaining data again using the method of the aforementioned steps to solve the matrix equation again, and the final results of x, y, z, l, m, and n as the measurement starting point and measurement vector of the sensor can be obtained to complete the calibration of the sensor.

[0100] In this embodiment, auxiliary parameters are used to construct a matrix equation for solution, and relevant data are obtained under different postures of the calibration plate, so that the final solution result can be universal, thereby improving the accuracy of calibration. Since some data are continuously deleted during the loop process to control the error of the matrix solution, and the establishment of the matrix equation is based on the measurement parameters of the target sensor and the thickness parameters of the calibration plate, the influence of the plane measurement accuracy and the sensor's own error can be effectively reduced during the optimization process, and the optimal matrix equation that meets the accuracy conditions can be obtained. By solving the target matrix equation, the target sensor parameters with higher accuracy can be quickly obtained to complete the calibration, thereby improving the quality of the method for calibrating the sensor.

[0101] Combined with attachment Figure 3 The application scenarios of the present application method shown are further explained in detail:

[0102] The laser displacement sensor 1 based on the principle of triangulation is adopted, the double-sided polished monocrystalline silicon wafer with a true thickness of 650 um (an error less than or equal to 3 um) and a surface roughness less than or equal to 1 um is used as a calibration panel 2, and an industrial camera 3 and a projector 4 form a structured light measurement system, and the laser displacement sensor 1 is located on both sides of the calibration panel, and the calibration panel 2 is clamped in the middle through a movable clamp 5.

[0103] Step one: adjust the clamp, change the attitude of the silicon wafer, the projector 4 projects the grating pattern to the F surface of the silicon wafer, the industrial camera 3 synchronously shoots and performs phase unwrapping and expansion to obtain the three-dimensional point cloud data of the F surface, fits the point cloud to a plane to obtain the plane equation A i x+B i y+C i z+D i =0, and the voltage value V returned by the laser displacement sensor is read at the same time i . Repeat the above steps until more than 100 sets of plane equations and laser displacement sensor return values are obtained.

[0104] Step two: based on the plane equation and sensor value obtained in the foregoing step, the F surface plane equation obtained for the i-th time is A i x+B i y+C i z+D i =0, since the Z surface and the F surface are parallel, the plane equation of the Z surface can be written as The sensor return value obtained for the i-th time is V i , and the coordinates of the point measured by the sensor on the plane Z are represented as (x+lV i , y+mV i , z+nV i ). Substituting the same into the plane Z equation can obtain:

[0105]

[0106] That is

[0107]

[0108] · [x y z l m n d] T = -D i

[0109] Thus, an equation group Er=b can be formed, where E is a coefficient matrix, r is a parameter matrix, and [E|b] is an augmented matrix. The least square method is used to solve r=(E T E) -1 E T b, and the value of d can be obtained from r, and Δ=|0.65-d| is calculated.

[0110] Step three: delete a row of [E|b], repeat step two, if the difference Δ between the thickness of the plate obtained by solving and the real thickness of the plate becomes smaller, keep deleting, otherwise, roll back the deleting operation (i.e. undo the deleting and add back the deleted data), select another set of data, and repeat step three.

[0111] Step four: until 15 sets of data are deleted or Δ≤0.01, repeat step two with the remaining data, and take the obtained x, y, z, l, m, n as the measurement starting point and the final result of the measurement vector of the sensor.

[0112] Referring to the drawings Figure 4 Based on the same inventive concept as in the foregoing embodiments, the embodiments of the present application also provide a laser displacement sensor calibration device, which comprises:

[0113] The construction module is configured to construct a matrix equation according to the auxiliary parameters and a plurality of first plane equations, wherein the auxiliary parameters comprise a measurement parameter of the target sensor, a thickness parameter of the calibration plate, and a return parameter obtained by the target sensor emitting laser to the calibration plate, the plurality of first plane equations are obtained under different postures of the calibration plate, and the matrix equation is established based on a coefficient matrix, a parameter matrix, and an augmented matrix;

[0114] The loop module is configured to delete any row elements of the augmented matrix and return to the step of constructing the matrix equation according to the auxiliary parameters and the plurality of first plane equations, until the matrix equation meets the accuracy condition to obtain a target matrix equation.

[0115] The solving module is configured to obtain a target measurement parameter of the target sensor according to the target matrix equation, so as to complete the calibration.

[0116] Those skilled in the art should understand that the division of each module in the embodiments is only a logical division of functions, and all or part of the modules can be integrated onto one or more actual carriers in actual applications, and the modules can all be implemented in the form of software through a processing unit, or all be implemented in the form of hardware, or be implemented in the form of software and hardware combination. It should be noted that the modules in the laser displacement sensor calibration device in the embodiments are one-to-one corresponding to the steps in the laser displacement sensor calibration method in the foregoing embodiments, and therefore, the specific embodiments of the present application can refer to the embodiments of the laser displacement sensor calibration method, which will not be described here.

[0117] Based on the same inventive concept as in the foregoing embodiments, the embodiments of the present application also provide a computer readable storage medium storing a computer program, which is loaded and executed by a processor to implement the laser displacement sensor calibration method provided by the embodiments of the present application.

[0118] Based on the same inventive concept as in the foregoing embodiments, the embodiments of the present application also provide an electronic device, comprising a processor and a memory, wherein,

[0119] The memory is configured to store a computer program.

[0120] The processor is configured to load and execute the computer program, so that the electronic device performs the laser displacement sensor calibration method provided by the embodiments of the present application.

[0121] In addition, based on the same inventive concept as in the foregoing embodiments, the embodiments of the present application also provide a computer program product, comprising a computer program, when the computer program is executed, is configured to perform the laser displacement sensor calibration method provided by the embodiments of the present application.

[0122] In some embodiments, the computer readable storage medium can be a memory such as FRAM, ROM, PROM, EPROM, EEPROM, flash memory, magnetic surface memory, optical disc, or CD-ROM, etc.; or can be various devices comprising one or any combination of the above memories. The computer can be various computing devices including smart terminals and servers.

[0123] In some embodiments, the executable instructions can be in the form of programs, software, software modules, scripts or codes, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and can be deployed in any form, including being deployed as independent programs or as modules, components, subroutines or other units suitable for use in computing environments.

[0124] As an example, the executable instructions can but not necessarily correspond to files in a file system, can be stored in part of a file storing other programs or data, for example, stored in one or more scripts in a Hyper Text Markup Language (HTML) document, stored in a single file dedicated to the program in question, or stored in multiple cooperating files (for example, files storing one or more modules, subroutines or code portions).

[0125] As an example, the executable instructions can be deployed to execute on one computing device, or on multiple computing devices located at one site, or on multiple computing devices distributed at multiple sites and interconnected through a communication network.

[0126] It should be noted that, in the present document, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a" does not, without further constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0127] The above-mentioned sequence numbers of the embodiments of the present application are only for description, and do not represent advantages or disadvantages of the embodiments.

[0128] Those skilled in the art can clearly understand the above-mentioned embodiment methods from the description of the above embodiments, which can be realized by means of software and necessary general hardware platforms, of course, can also be realized by hardware, but in many cases, the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which is stored in a storage medium (such as a read-only memory / random access memory, a magnetic disk, an optical disk), and includes a plurality of instructions for enabling a multimedia terminal device (which can be a mobile phone, a computer, a television receiver, or a network device, etc.) to execute the methods described in various embodiments of the present application.

[0129] In summary, the application provides a laser displacement sensor calibration method, device, storage medium and electronic equipment, comprising: constructing a matrix equation according to auxiliary parameters and a plurality of first plane equations; wherein the auxiliary parameters include: the measurement parameters of the target sensor, the thickness parameters of the calibration plate, and the return parameters obtained by the target sensor emitting laser to the calibration plate, the plurality of first plane equations are obtained under different postures of the calibration plate, and the matrix equation is established based on a coefficient matrix, a parameter matrix and an augmented matrix; deleting any row elements of the augmented matrix, and returning to the step of constructing the matrix equation according to the auxiliary parameters and the plurality of first plane equations, until the matrix equation meets the accuracy condition to obtain a target matrix equation; obtaining the target measurement parameters of the target sensor according to the target matrix equation to complete the calibration. The method of the application uses auxiliary parameters to construct a matrix equation for solving, and the related data obtained under different postures of the calibration plate makes the final solving result universal, improves the accuracy of calibration, and since some data is constantly tried to be deleted in the loop process to control the error of matrix solving, and the establishment of the matrix equation is derived from the measurement parameters of the target sensor and the thickness parameters of the calibration plate, the influence of plane measurement accuracy and sensor self-error can be effectively reduced in the optimization process, and then the optimal matrix equation meeting the accuracy condition is obtained, and the target sensor parameters with high accuracy can be quickly obtained by solving the target matrix equation to complete the calibration, and the quality of the sensor calibration method is improved.

[0130] The above only describes the preferred embodiments of the application and is not intended to limit the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A laser displacement sensor calibration method, characterized in that: The following steps are involved: Constructing a matrix equation based on auxiliary parameters and a plurality of first plane equations; wherein the auxiliary parameters include: a measurement parameter of a target sensor, a thickness parameter of a calibration plate, and a return parameter obtained by the target sensor emitting a laser at the calibration plate; the plurality of first plane equations are obtained at different postures of the calibration plate; and the matrix equation is established based on a coefficient matrix, a parameter matrix, and an augmented matrix; Deleting any row element of the augmented matrix and returning to the step of constructing a matrix equation according to the auxiliary parameters and the plurality of first plane equations until the matrix equation satisfies the accuracy condition to obtain a target matrix equation; deleting any row element of the augmented matrix and returning to the step of constructing a matrix equation according to the auxiliary parameters and the plurality of first plane equations until the matrix equation satisfies the accuracy condition to obtain a target matrix equation, including: Deleting any row element of the augmented matrix, and returning to the step of constructing a matrix equation according to the auxiliary parameters and the first plane equations; Solving the parameter matrix to obtain the predicted thickness of the calibration plate; If the thickness difference between the predicted thickness of the calibration plate and the actual thickness of the calibration plate is decreasing, returning to delete any row element of the augmented matrix, and returning to the step of constructing a matrix equation according to the auxiliary parameters and the plurality of first plane equations until the matrix equation meets the accuracy condition, thereby obtaining a target matrix equation; According to the target matrix equation, the target measurement parameters of the target sensor are obtained to complete the calibration.

2. The laser displacement sensor calibration method according to claim 1, characterized in that: The matrix equation is constructed based on the auxiliary parameters and the first plane equations, including: Obtaining simultaneous equations according to the measurement parameters of the target sensor, the thickness parameters of the calibration plate, the return parameters, and a plurality of first plane equations; According to the simultaneous equations, a coefficient matrix, a parameter matrix and an augmented matrix are obtained; A matrix equation is constructed according to the coefficient matrix, the parameter matrix and the augmented matrix.

3. The laser displacement sensor calibration method according to claim 1, characterized in that: The plane corresponding to the first plane equation is the first surface of the calibration plate, and the first surface of the calibration plate is the surface on which the laser emitted by the target sensor is received. Before constructing the matrix equation based on the auxiliary parameters and the plurality of first plane equations, the laser displacement sensor calibration method further includes: According to several second plane equations and the thickness parameter of the calibration plate, several first plane equations are obtained; wherein the plane corresponding to the second plane equation is the second surface of the calibration plate, and the second surface of the calibration plate is the surface away from the first surface thereof.

4. The laser displacement sensor calibration method according to claim 3, characterized in that: Before obtaining the plurality of first plane equations according to the plurality of second plane equations and the thickness parameter of the calibration plate, the laser displacement sensor calibration method further includes: Obtaining three-dimensional point cloud data on the second surface of the calibration plate in different postures of the calibration plate; Plane fitting is performed on the three-dimensional point cloud data in different postures to obtain a plurality of second plane equations.

5. The laser displacement sensor calibration method according to claim 4, characterized in that: The obtaining of three-dimensional point cloud data on the second surface of the calibration plate in different postures of the calibration plate includes: Obtaining grating projection images on the second surface of the calibration plate at different postures of the calibration plate; De-phase the grating projection image to obtain three-dimensional point cloud data on the second surface of the calibration plate.

6. The laser displacement sensor calibration method according to claim 1, characterized in that: Before the thickness difference between the predicted thickness of the calibration plate and the actual thickness of the calibration plate changes to a smaller value, the laser displacement sensor calibration method further includes: Determine the change in the thickness difference.

7. The laser displacement sensor calibration method according to claim 6, characterized in that: If the result of determining the change in the thickness difference is not that the thickness difference is decreasing, executing: The deleted elements of the augmented matrix are added back to the augmented matrix, and the process of deleting any row element of the augmented matrix and constructing the matrix equation according to the measurement parameters of the target sensor and the first plane equation is returned.

8. The laser displacement sensor calibration method according to claim 1, characterized in that: The accuracy condition includes: the number of deleted elements in the augmented matrix reaches a target number of rows or the thickness difference is not greater than a preset value.

9. A laser displacement sensor calibration device, characterized in that: include: A construction module, the construction module being configured to construct a matrix equation based on auxiliary parameters and a plurality of first plane equations; wherein the auxiliary parameters include: a measurement parameter of a target sensor, a thickness parameter of a calibration plate, and a return parameter obtained by the target sensor emitting a laser at the calibration plate; the plurality of first plane equations are obtained at different postures of the calibration plate; and the matrix equation is established based on a coefficient matrix, a parameter matrix, and an augmented matrix; A loop module is configured to delete any row element of the augmented matrix and return to the step of constructing a matrix equation according to the auxiliary parameters and the plurality of first plane equations until the matrix equation satisfies the accuracy condition and obtains the target matrix equation; the step of deleting any row element of the augmented matrix and returning to the step of constructing a matrix equation according to the auxiliary parameters and the plurality of first plane equations until the matrix equation satisfies the accuracy condition and obtains the target matrix equation, including: Deleting any row element of the augmented matrix, and returning to the step of constructing a matrix equation according to the auxiliary parameters and the first plane equations; Solving the parameter matrix to obtain the predicted thickness of the calibration plate; If the thickness difference between the predicted thickness of the calibration plate and the actual thickness of the calibration plate is decreasing, returning to delete any row element of the augmented matrix, and returning to the step of constructing a matrix equation according to the auxiliary parameters and the plurality of first plane equations until the matrix equation meets the accuracy condition, thereby obtaining a target matrix equation; A solution module is used to obtain target measurement parameters of the target sensor according to the target matrix equation to complete calibration.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is loaded and executed by a processor, the laser displacement sensor calibration method according to any one of claims 1 to 8 is implemented.

11. An electronic device, characterized in that: comprising a processor and a memory, wherein: The memory is used to store computer programs; The processor is configured to load and execute the computer program so that the electronic device executes the laser displacement sensor calibration method according to any one of claims 1 to 8.

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