CN112147625B

CN112147625B - Calibration method, device, monocular laser measurement equipment and calibration system

Info

Publication number: CN112147625B
Application number: CN202011002827.8A
Authority: CN
Inventors: 王维林
Original assignee: Autel Intelligent Technology Corp Ltd
Current assignee: Autel Intelligent Technology Corp Ltd
Priority date: 2020-09-22
Filing date: 2020-09-22
Publication date: 2024-03-01
Anticipated expiration: 2040-09-22
Also published as: WO2022062901A1; CN112147625A

Abstract

The invention relates to the technical field of laser calibration, and discloses a calibration method, a calibration device, monocular laser measurement equipment and a calibration system, wherein the method comprises the following steps: acquiring a laser line image of a target acquired by a camera; determining the laser groove depth of each groove of the groove region according to the laser line image; determining a loss function corresponding to an initial parameter value of a preset laser plane equation according to the laser groove depth of each groove and the standard groove depth corresponding to each groove one by one; and updating the initial parameter value according to the loss function to determine an updated parameter value, and determining a calibrated laser plane equation. By arranging a plurality of grooves with different depths in the groove area, constructing a loss function, updating parameter values based on the loss function to determine a calibrated laser plane equation.

Description

Calibration method, device, monocular laser measurement equipment and calibration system

Technical Field

The invention relates to the technical field of laser calibration, in particular to a calibration method, a calibration device, monocular laser measurement equipment and a calibration system.

Background

In the field of high-precision measurement, a monocular laser triangulation method occupies a very important position, and the measurement precision can be within 0.05 mm. The field of monocular laser triangulation is very wide, and particularly in certain special application scenes, such as automobile brake disc abrasion measurement and tire tread abrasion measurement, if the conventional vernier caliper is used for measurement, an automobile rim needs to be disassembled, so that the operation is inconvenient; either the selected measurement points are inconsistent or an artificial measurement error, it is difficult to obtain accurate results, and monocular laser measurement devices easily solve these problems.

In monocular laser measurement, the coordinates of the laser line reflected by the measurement target object in the camera coordinate system need to be calculated, and the plane coordinate equation of the laser light knife plane in the camera coordinate system needs to be known. The accuracy of the plane coordinate equation of the laser optical cutter has great influence on measurement precision, and the precision measurement requirement of the equipment for maintaining the precise plane parameters is very high. Especially, after the equipment leaves the factory, along with aging, deformation and other external factors of the laser, the plane equation of the laser optical knife calibrated by the factory may not be accurate any more and needs to be calibrated again, but the maintenance of the factory is difficult.

In the process of realizing the invention, the inventor finds that the current calibration method fits a laser light knife plane equation through laser linear equations on a plurality of poses, and light supplementing is needed in the measurement process, so that the calibration time is long, the influence of the environment is larger, and the calibration precision is insufficient.

Disclosure of Invention

The embodiment of the invention aims to provide a calibration method, a device, monocular laser measurement equipment and a calibration system, which solve the technical problems of long calibration time and insufficient calibration precision in the conventional calibration method, realize the reduction of the calibration time and improve the calibration accuracy.

In order to solve the technical problems, the embodiment of the invention provides the following technical scheme:

in a first aspect, an embodiment of the present invention provides a calibration method applied to a monocular laser calibration system, where the monocular laser calibration system includes a target and a monocular laser measurement device, the target includes a groove area, the groove area includes a plurality of grooves with different depths, the monocular laser measurement device includes a laser and a camera, and laser output by the laser is projected on the target, and the method includes:

acquiring a laser line image of the target acquired by the camera;

Determining the laser groove depth of each groove of the groove region according to the laser line image;

determining a loss function corresponding to an initial parameter value of a preset laser plane equation according to the laser groove depth of each groove and the standard groove depth corresponding to each groove one by one;

and updating the initial parameter value according to the loss function to determine an updated parameter value, and determining a calibrated laser plane equation.

In some embodiments, the determining the laser groove depth of each groove of the groove region from the laser line image comprises:

determining the pixel coordinates of the bottom point and the reference point of each groove according to the laser line image;

determining the laser coordinates of the bottom point of each groove and the reference point according to the pixel coordinates of the bottom point of each groove and the reference point;

determining a reference straight line corresponding to each groove according to the laser coordinates of the reference points;

and determining the laser groove depth of each groove according to the reference straight line corresponding to each groove.

In some embodiments, the determining the laser coordinates of the bottom point of each groove and the reference point according to the pixel coordinates of the bottom point of each groove and the reference point includes:

Determining camera coordinates of the bottom point of each groove and the reference point according to the pixel coordinates of the bottom point of each groove and the reference point;

and determining the laser coordinates of the bottom point of each groove and the reference point according to the camera coordinates of the bottom point of each groove and the reference point.

In some embodiments, the determining the camera coordinates of the bottom point of each groove and the reference point according to the pixel coordinates of the bottom point of each groove and the reference point comprises:

and determining the camera coordinates of the bottom point and the reference point of each groove according to the pixel coordinates of the bottom point and the reference point of each groove through the internal reference matrix of the camera.

In some embodiments, the determining the laser coordinates of the bottom point of each groove and the reference point according to the camera coordinates of the bottom point of each groove and the reference point includes:

and determining the laser coordinates of the bottom point of each groove and the reference point through a rotation matrix of the camera coordinate system and the laser coordinate system according to the camera coordinates of the bottom point of each groove and the reference point.

In some embodiments, the determining a reference line corresponding to each groove according to the laser coordinates of the reference point includes:

Determining laser coordinates of a first reference point and a second reference point corresponding to each groove;

and determining a reference straight line corresponding to each groove according to the laser coordinates of the first reference point and the second reference point corresponding to each groove.

In some embodiments, it is assumed that the laser coordinates of the first reference point are (x _L ^P1 ，y _L ^P1 ) The laser coordinates of the second reference point are (x) _L ^P2 ，y _L ^P2 ) Determining that the reference straight line is:

y=kx+m, wherein,m＝y _L ^P1 -k*x _L ^P1 。

in some embodiments, the determining the laser groove depth of each groove according to the reference straight line corresponding to each groove includes: let the laser groove depth of the ith groove be d _i And determining the depth of the laser groove as follows:

wherein d _i The laser groove depth for the ith groove, s+1 is the number of bottom points of the ith groove, (x) _Li ，y _Li ) The laser coordinates, k, of the ith reference point in the ith groove _i Slope, m of reference straight line corresponding to the ith groove _i Is the intercept of the reference line corresponding to the i-th groove.

In some embodiments, the loss function is:

wherein (a, b, c) is the initial parameter value of the preset laser plane equation, a is the first parameter, b is the second parameter, c is the third parameter, d _i Laser groove depth, D, for the (i+1) th groove _i The standard groove depth of the (i+1) th groove is the number of grooves in the groove region, and n+1 is the standard groove depth of the (i+1) th groove.

In some embodiments, said updating said initial parameter value according to said loss function to determine an updated parameter value comprises:

assuming that the initial parameter value of the preset laser plane equation is (a, b, c), then

Wherein lambda is _a Lambda is the first learning rate _b Lambda is the second learning rate _c For the third learning rate, loss (a, b, c) is a Loss function.

In some embodiments, the determining the calibrated laser plane equation includes:

according to the equation: z=ax+by+c, wherein,the calibrated laser plane equation is determined as follows: ax+by+cz+d=0.

In some embodiments, the method further comprises:

and carrying out iterative computation for a plurality of times according to the updated parameter value to update the parameter value until a termination condition is met, wherein the termination condition comprises that the loss value of the loss function is smaller than a preset loss threshold value, and/or the iterative computation times are larger than a preset times threshold value, and/or the learning rate is smaller than a preset learning rate threshold value.

In a second aspect, an embodiment of the present invention provides a calibration device applied to a monocular laser calibration system, where the monocular laser calibration system includes a target and a monocular laser measurement device, the target includes a groove area, the groove area includes a plurality of grooves with different depths, the monocular laser measurement device includes a laser and a camera, and laser output by the laser is projected on the target, where the device includes:

The laser line image unit is used for acquiring the laser line image of the target acquired by the camera;

a laser groove depth unit for determining the laser groove depth of each groove of the groove region according to the laser line image;

the loss function unit is used for determining a loss function corresponding to an initial parameter value of a preset laser plane equation according to the laser groove depth of each groove and the standard groove depth corresponding to each groove one by one;

and the calibration unit is used for updating the initial parameter value according to the loss function to determine an updated parameter value and determining a calibrated laser plane equation.

In some embodiments, the laser groove depth unit comprises:

the pixel coordinate module is used for determining the pixel coordinates of the bottom point and the reference point of each groove according to the laser line image;

the laser coordinate module is used for determining the laser coordinates of the bottom point of each groove and the reference point according to the pixel coordinates of the bottom point of each groove and the reference point;

the reference straight line module is used for determining a reference straight line corresponding to each groove according to the laser coordinates of the reference point;

and the laser groove depth module is used for determining the laser groove depth of each groove according to the reference straight line corresponding to each groove.

In some embodiments, the laser coordinate module is specifically configured to:

In some embodiments, the reference straight line module is specifically configured to:

y=kx+m, wherein,m＝y _L ^P1 -k*x _L ^P1 。

in some embodiments, the laser groove depth module is specifically configured to:

let the laser groove depth of the ith groove be d _i And determining the depth of the laser groove as follows:

wherein d _i The laser groove depth for the ith groove, s+1 is the number of bottom points of the ith groove, (x) _Lj ，y _Lj ) The laser coordinates, k, of the jth reference point in the ith groove _i Slope, m of reference straight line corresponding to the ith groove _i Is the intercept of the reference line corresponding to the i-th groove.

In some embodiments, the loss function is:

In some embodiments, the calibration unit is specifically configured to:

Wherein lambda is _a Lambda is the first learning rate _b Lambda is the second learning rate _c For the third learning rate of the first learning rate,loss (a, b, c) is a Loss function.

In some embodiments, the calibration unit is specifically configured to:

In some embodiments, the apparatus further comprises:

and the iteration unit is used for carrying out iterative computation for a plurality of times according to the updated parameter value to update the parameter value until a termination condition is met, wherein the termination condition comprises that the loss value of the loss function is smaller than a preset loss threshold value, and/or the iterative computation frequency is larger than a preset frequency threshold value, and/or the learning rate is smaller than a preset learning rate threshold value.

In a third aspect, an embodiment of the present invention provides a monocular laser measurement apparatus, including:

at least one processor; and

a memory communicatively coupled to the at least one processor; wherein,

the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the calibration method as described above.

In a fourth aspect, an embodiment of the present invention provides a monocular laser calibration system, including:

a target;

a monocular laser measuring apparatus as described above;

wherein the monocular laser measuring apparatus includes: the laser device comprises a laser and a camera, wherein laser output by the laser device is projected on the target, and the camera is used for acquiring an image of the target;

wherein the target comprises a groove region comprising a plurality of grooves of different depths.

In a fifth aspect, embodiments of the present invention provide a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements a calibration method as described above.

The embodiment of the invention has the beneficial effects that: in contrast to the situation in the prior art, the calibration method provided by the embodiment of the invention is applied to a monocular laser calibration system, the monocular laser calibration system comprises a target and monocular laser measurement equipment, the target comprises a groove area, the groove area comprises a plurality of grooves with different depths, the monocular laser measurement equipment comprises a laser and a camera, and laser output by the laser is projected on the target, and the method comprises the following steps: acquiring a laser line image of the target acquired by the camera; determining the laser groove depth of each groove of the groove region according to the laser line image; determining a loss function corresponding to an initial parameter value of a preset laser plane equation according to the laser groove depth of each groove and the standard groove depth corresponding to each groove one by one; and updating the initial parameter value according to the loss function to determine an updated parameter value, and determining a calibrated laser plane equation. By arranging a plurality of grooves with different depths in the groove area, constructing a loss function, updating parameter values based on the loss function to determine a calibrated laser plane equation.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements, and in which the figures of the drawings are not to be taken in a limiting sense, unless otherwise indicated.

FIG. 1 is a schematic diagram of a monocular laser calibration system according to an embodiment of the present invention;

FIG. 2 is a schematic flow chart of a calibration method according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a standard target groove image provided by an embodiment of the present invention;

FIG. 4 is a schematic illustration of a laser line image provided by an embodiment of the present invention;

fig. 5 is a detailed flowchart of step S20 in fig. 2;

fig. 6 is a detailed flowchart of step S22 in fig. 5;

fig. 7 is a detailed flowchart of step S23 in fig. 5;

FIG. 8 is a schematic structural diagram of a calibration device according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a monocular laser measuring apparatus according to an embodiment of the present invention.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.

In a monocular laser measurement system, the parameter equation ax+by+cy+d=0 for the laser-optical-knife plane needs to be calibrated before measurement. The traditional calibration method generally comprises the steps of arranging targets on a plurality of pose, measuring plane equations of the target planes by using a camera, starting laser, analyzing straight line equations of laser lines on the target planes, and finally fitting laser light knife plane equations by using the laser straight line equations on the plurality of pose. The calibration method needs multiple measurements, light supplementing is needed in the measurement process, the operation is inconvenient, and the efficiency is low. In addition, after the product leaves the factory, the customer can not use the product to self-calibrate due to complex operation. According to the scheme, the standard depth groove target is introduced, the gradient descent method in the deep learning is adopted to automatically calculate the plane of the laser optical cutter, so that the working efficiency can be improved, the measurement precision is optimized, the calibration operation is simplified, and the method is suitable for production of clients and factories.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a monocular laser calibration system according to an embodiment of the present invention;

As shown in fig. 1, the monocular laser calibration system 100 includes:

a monocular laser measurement device 10, a target 20, and a holder (not shown) to which the monocular laser device 10 is fixed.

Wherein the monocular laser measuring apparatus includes: the monocular laser measuring device comprises a laser 11 and a camera 12, wherein the laser 11 and the camera 12 are fixed on the support, and the monocular laser measuring device further comprises a light supplementing lamp, an optical filter, a pose adjusting device, a host, a display system, a power supply, a base and the like. The host may run a variety of platforms, such as Linux, android, windows.

The target 20 includes a base area 21 and a groove area 22, wherein the base area includes a base, the pose adjusting device is disposed at a position where the base is located, and the groove area includes a plurality of grooves with different depths. It will be appreciated that the laser may be a laser of a variety of wavelength bands, such as the red 650nm band, the green 520nm band, etc.

For the groove region of the target, the groove region comprises a plurality of grooves with different depths and a background region, wherein the colors of the groove region and the background region are different. In some embodiments, the background area may be further coated with a reflective material to increase the reflective function of the background area, while the reflective function of the groove area is weaker than the reflective function of the background area, so that the imaging difference between the groove area and the background area in the camera is larger, thereby enabling the camera to obtain a high quality target image.

For the laser and the camera, as the laser and the camera are fixed on the bracket, the positions of the laser and the camera are relatively fixed, and when the bracket moves, the camera and the laser synchronously move. Because the camera and the laser move synchronously, the position of the laser in the camera coordinate system of the camera is not changed, and similarly, the position of the laser plane output by the laser in the camera coordinate system is not changed.

Noteworthy are: the shooting direction of the camera and the laser plane where the laser output by the laser is located form a fixed included angle, and the fixed included angle is 25-30 degrees. When the support moves in the vertical direction, the positions of intersecting lines of the target and the laser plane output by the laser are different, and similarly, when the target moves in the vertical direction, the positions of intersecting lines of the target and the laser plane output by the laser are also different.

It should be noted that: because the positions of the laser and the camera are relatively fixed, the position of the laser plane output by the laser in the camera coordinate system of the camera is also fixed, even if the bracket is moved, the position of the laser plane in the camera coordinate system is not influenced, the monocular laser measuring equipment is placed in a base area of the target, line laser is vertically projected to a groove area on the target, the camera is offset from the laser projection direction by a certain angle to take a picture, the depth of the groove on the target can be measured by a laser triangulation principle, and the calibration method of the invention is specifically described below.

Referring to fig. 2, fig. 2 is a flow chart of a calibration method according to an embodiment of the invention; the calibration method is applied to a monocular laser calibration system, the monocular laser calibration system comprises a target and monocular laser measurement equipment, the target comprises a groove area, the groove area comprises a plurality of grooves with different depths, the monocular laser measurement equipment comprises a laser and a camera, laser light output by the laser is projected on the target, wherein an execution body of the calibration method is the monocular laser measurement equipment, specifically, the execution body of the calibration method is a controller of the monocular laser measurement equipment, in other embodiments, the controller 313 can also be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), ARM (Acorn RISC Machine) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components or any combination of the components; but also may be any conventional processor, controller, microcontroller, or state machine; may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other configuration. The calibration method can be used for monocular laser measuring equipment of non-handheld equipment.

As shown in fig. 2, the calibration method includes:

step S10: acquiring a laser line image of the target acquired by the camera;

specifically, the monocular laser measuring equipment is placed in the base area of the target, line laser output by the laser of the monocular laser measuring equipment vertically projects into the groove area of the target, the shooting direction of the camera and the laser plane where the laser output by the laser is located form a fixed included angle, the fixed included angle range is 25-30 degrees, the camera offsets the fixed included angle of the laser projection direction to shoot, obtain the laser line image of the target, and send the laser line image of the target to the controller of the monocular laser measuring equipment, so that the controller obtains the laser line image of the target collected by the camera.

Step S20: determining the laser groove depth of each groove of the groove region according to the laser line image;

referring to fig. 3 again, fig. 3 is a schematic diagram of a standard target groove image according to an embodiment of the present invention;

the method comprises the steps of placing monocular laser measuring equipment in a base area on a target, starting a laser on the monocular laser measuring equipment, projecting laser emitted by the laser to a groove area of the target, wherein the groove area comprises a plurality of grooves with different depths, each groove is a groove with standard depth, the depth of each groove is determined, each groove corresponds to one standard depth, the number of the grooves in the groove area can be flexibly configured, the shape and the groove design of the target can be non-square, the shape can be other, and a camera on the monocular laser measuring equipment acquires laser line images of the groove area of the target.

Referring to fig. 4 again, fig. 4 is a schematic diagram of a laser line image according to an embodiment of the invention;

as shown in fig. 4, the laser line image includes a plurality of grooves, where each groove corresponds to a reference point and a bottom point, where the reference point is a point on two sides of the groove, and the bottom point is a point on the bottom of the groove.

Specifically, referring to fig. 5 again, fig. 5 is a detailed flowchart of step S20 in fig. 2;

as shown in fig. 5, this step S20: determining a laser groove depth of each groove of the groove region according to the laser line image, including:

step S21: determining the pixel coordinates of the bottom point and the reference point of each groove according to the laser line image;

specifically, the bottom point of the groove is a point at the position of the groove, the reference points are points at two sides of the groove, wherein the laser line image is an image under a pixel coordinate system acquired by a camera, the position of each groove can be analyzed through the laser line image, and the pixel coordinate of the bottom point of each groove and the pixel coordinate of the reference points at two sides of the groove are determined, wherein the bottom point of each groove forms a point set Pi, and the reference points at two sides of each groove are two, for example: the reference point on the left side of the groove is a first reference point P1, and the reference point on the right side of the groove is a second reference point P2.

Step S22: determining the laser coordinates of the bottom point of each groove and the reference point according to the pixel coordinates of the bottom point of each groove and the reference point;

wherein, assuming that the pixel coordinates are (u, v), the pixel coordinates (u, v) need to be converted into camera coordinates (x) by projection transformation _c ，y _c ，z _c ) The camera coordinates (x _c ，y _c ，z _c ) Converted into laser coordinates (x _L ，y _L ，z _L )。

Specifically, referring to fig. 6 again, fig. 6 is a detailed flowchart of step S22 in fig. 5;

as shown in fig. 6, this step S22: determining laser coordinates of the bottom point and the reference point of each groove according to pixel coordinates of the bottom point and the reference point of each groove, including:

step S221: determining camera coordinates of the bottom point of each groove and the reference point according to the pixel coordinates of the bottom point of each groove and the reference point;

specifically, assuming that the pixel coordinates of the bottom point of each groove and the reference point are (u, v), thenWherein A is an internal reference matrix of the camera, and the internal reference matrix is obtained after conversion: />Wherein A is ^-1 The reference matrix of the camera is an inverse matrix of the reference matrix of the camera, wherein the reference matrix of the camera is in the prior art, and is not described herein. The pixel coordinate system can be converted into the camera coordinate system by using an internal reference matrix of the camera of the monocular laser measuring apparatus, thereby converting the pixel coordinates of the bottom point and the reference point of each groove into the camera coordinates of the bottom point and the reference point of each groove.

Step S222: and determining the laser coordinates of the bottom point of each groove and the reference point according to the camera coordinates of the bottom point of each groove and the reference point.

Specifically, it is assumed that the camera coordinates of the bottom point of each groove and the reference point are (x _c ，y _c ，z _c ) The laser coordinates of the bottom point of each groove and the reference point are (x _L ，y _L ，z _L ) ThenWherein, R is a rotation matrix, and the conversion can be carried out: />Wherein R is ^-1 Is the inverse of the rotation matrix.

It is understood that since the laser and the camera are fixedly arranged on the bracket, the laser and the camera are fixed on the bracketThe plane equation ax+by+cz+d=0 of the laser plane in the camera coordinate system and the rotation matrix R between the camera coordinate system and the laser coordinate system, the camera coordinate system and the origin of the laser coordinate system coincide, the X-axis of the laser coordinate system is parallel to the X-axis of the camera coordinate system, the normal vector of the laser planeIs Z axis, laser projection direction y _L Is the normal vector of the X-axis direction and the laser plane +.>Is a cross product of (a). By using the rotation matrix, the camera coordinate system can be converted to the laser coordinate system, thereby converting the camera coordinates of the bottom point and the reference point of each groove to the laser coordinates of the bottom point and the reference point of each groove.

Where the laser plane equation ax+by+cz+d=0, can be simplified as: z=ax+by+c, wherein,wherein the rotation matrix R is a function of (a, b, c), and the rotation matrix R is defined as R (a, b, c), and can be obtained: />

According toThe method can obtain: /> I.e.In combination with the above formula z=ax+by+c, wherein +.>The method can obtain:

combined type upper partAnd +.>It can be known that: laser coordinates (x) _L ，y _L ，z _L ) Is a function of each of the parameters (a, b, c) and (x ', y'), thus x _L Can be expressed as x _L ＝f(a，b，c，x’，y’)，y _L Can be expressed as y _L =g (a, b, c, x ', y'), where f, g represent functions, i.e. x _L Is expressed as x _L ＝f(a，b，c，x’，y’)，y _L Is expressed as a function of y _L ＝g(a，b，c，x’，y’)。

It will be appreciated that the laser coordinates (x _L ，y _L ，z _L ) Is associated with the parameter values (a, b, c) of the laser plane equation, so that, in order to determine the laser coordinates, it is necessary to give the initial parameter values (a, b, c) of the laser plane equation that are preset.

Step S23: determining a reference straight line corresponding to each groove according to the laser coordinates of the reference points;

specifically, referring to fig. 7 again, fig. 7 is a detailed flowchart of step S23 in fig. 5;

as shown in fig. 7, this step S23: according to the laser coordinates of the reference points, determining a reference straight line corresponding to each groove comprises:

Step S231: determining laser coordinates of a first reference point and a second reference point corresponding to each groove;

specifically, the reference point of each groove comprises a first reference point and a second reference pointThe reference point, through the first reference point and the second reference point, can determine the reference straight line corresponding to each groove, assuming that the first reference point is P1, and the laser coordinates of P1 are (x _L ^P1 ，y _L ^P1 ) The second reference point is P2, and the laser coordinate of P2 is (x _L ^P2 ，y _L ^P2 )。

Specifically, the determining the laser coordinates of the first reference point and the second reference point corresponding to each groove includes:

fitting a groove straight line of each groove of the groove region according to a plurality of bottom points of each groove, determining leftmost points and rightmost points of the plurality of bottom points positioned on the groove straight line, determining a point positioned on the left side of the leftmost point and separated from the leftmost point by a preset distance and positioned on a laser line as a first reference point, determining a point positioned on the right side of the rightmost point and separated from the rightmost point by a preset distance and positioned on the laser line as a second reference point.

Step S232: and determining a reference straight line corresponding to each groove according to the laser coordinates of the first reference point and the second reference point corresponding to each groove.

Specifically, assuming that the reference line corresponding to each groove is y=kx+m, where k is the slope of the reference line and m is the intercept of the reference line, thenm＝y _L ^P1 -k*x _L ^P1 。

Step S24: and determining the laser groove depth of each groove according to the reference straight line corresponding to each groove.

Specifically, each groove corresponds to a reference straight line one by one, and the laser groove depth of the ith groove is assumed to be d _i The laser groove depth of each groove is determined as follows:

It will be appreciated that the laser coordinates (x _L ，y _L ，z _L ) Related to the parameter values (a, b, c) of the laser plane equation, i.e. x _L 、y _L Associated with parameter values (a, b, c), x _Li 、y _Li Is related to the parameter value (a, b, c), thus d _i Is a function of the parameter values (a, b, c).

Step S30: determining a loss function corresponding to an initial parameter value of a preset laser plane equation according to the laser groove depth of each groove and the standard groove depth corresponding to each groove one by one;

Specifically, each groove corresponds to a standard groove depth, and the initial parameter value of the preset laser plane equation is (a, b, c), where the initial parameter value may be a parameter value when leaving the factory or a parameter value when last calibrating, and in this embodiment of the present invention, the initial parameter value is preferably a parameter value when last calibrating, so as to improve the convergence speed when calibrating and reduce the convergence time.

The loss function corresponding to the initial parameter value of the determined preset laser plane equation is as follows:

It will be appreciated that due to the laser groove depth d of the ith groove _i Associated with the initial parameter value (a, b, c), thenThe loss function is related to the initial parameter values (a, b, c) of the predetermined laser plane equation.

Step S40: and updating the initial parameter value according to the loss function to determine an updated parameter value, and determining a calibrated laser plane equation.

And updating the initial parameter value based on a gradient descent method according to the loss function to determine an updated parameter value, and determining a calibrated laser plane equation based on the updated parameter value.

Specifically, assuming that the initial parameter value of the preset laser plane equation is (a, b, c), then

Wherein lambda is _a Lambda is the first learning rate _b Lambda is the second learning rate _c For a third learning rate, loss (a, b, c) is a Loss function, the first learning rate lambda _a Corresponding to the first parameter a, for updating the first parameter a, the second learning rate lambda _b Corresponding to the second parameter b, for updating the second parameter b, the third learning rate lambda _c And corresponding to the third parameter c, updating the third parameter c. It can be appreciated that the first learning rate lambda _a Second learning rate lambda _b Third learning rate lambda _c The three can be set to be the same or different according to the dynamic adjustment of the actual situation. Specifically, the method further comprises the following steps: dynamically adjusting the first learning rate lambda _a Second learning rate lambda _b Third learning rate lambda _c So as to reduce the convergence time when the gradient is reduced and improve the accuracy of the first parameter a, the second parameter b and the third parameter c.

Specifically, determining the calibrated laser plane equation based on the updated parameter value includes:

According to the equation: z=ax+by+c, wherein,determination ofThe calibrated laser plane equation is as follows: ax+by+cz+d=0.

In an embodiment of the present invention, the method further includes:

Specifically, the preset loss threshold is not greater than 0.001, the preset times threshold is not less than 10000, and the preset learning rate threshold includes a first preset learning rate threshold, a second preset learning rate threshold and a third preset learning rate threshold, where the first preset learning rate threshold, the second preset learning rate threshold and the third preset learning rate threshold are not greater than 0.001.

In an embodiment of the present invention, the method further includes:

and verifying the calibrated laser plane equation.

Specifically, the verifying the calibrated laser plane equation includes:

determining the depth of the laser groove calculated by the laser plane equation according to the parameter value corresponding to the laser plane equation and combining the bottom point corresponding to any groove,

If the error between the depth of the laser groove and the depth of the standard groove, which is calculated by the laser plane equation, is smaller than a preset error threshold, the verification is successful;

if the error between the laser groove depth calculated by the laser plane equation and the standard groove depth is greater than or equal to a preset error threshold, verification fails.

The traditional calibration method has the advantages that the related environmental factors are more, the calibration precision is more difficult to further improve, the requirement on the calibration environment is less, the light supplement to the target is not needed, the placement pose of the target is identified, the cost is low, and compared with the traditional laser line calibration method, more than 30 minutes are often needed to finish one calibration, and the calibration method provided by the invention only needs to execute 10000 iterative operations within 1 minute so as to achieve the calibration precision and improve the precision.

Meanwhile, compared with the traditional method, the method has stronger skill requirements on operators, the method is simple to operate, only places equipment on a target, executes a calibration function, automatically completes calibration, and further improves the operability of the calibration.

In an embodiment of the present invention, a calibration method is provided and applied to a monocular laser calibration system, where the monocular laser calibration system includes a target and a monocular laser measurement device, the target includes a groove area, the groove area includes a plurality of grooves with different depths, the monocular laser measurement device includes a laser and a camera, and laser output by the laser is projected on the target, and the method includes: acquiring a laser line image of the target acquired by the camera; determining the laser groove depth of each groove of the groove region according to the laser line image; determining a loss function corresponding to an initial parameter value of a preset laser plane equation according to the laser groove depth of each groove and the standard groove depth corresponding to each groove one by one; and updating the initial parameter value according to the loss function to determine an updated parameter value, and determining a calibrated laser plane equation. By arranging a plurality of grooves with different depths in the groove area, constructing a loss function, updating parameter values based on the loss function to determine a calibrated laser plane equation.

Referring to fig. 8 again, fig. 8 is a schematic structural diagram of a calibration device according to an embodiment of the present invention; the device is applied to a monocular laser calibration system, the monocular laser calibration system comprises a target and monocular laser measuring equipment, the target comprises a groove area, the groove area comprises grooves with different depths, the monocular laser measuring equipment comprises a laser and a camera, and laser output by the laser is projected to the target.

As shown in fig. 8, the calibration device 80 includes:

a laser line image unit 81, configured to acquire a laser line image of the target acquired by the camera;

a laser groove depth unit 82 for determining a laser groove depth of each groove of the groove region from the laser line image;

a loss function unit 83, configured to determine a loss function corresponding to an initial parameter value of a preset laser plane equation according to a laser groove depth of each groove and a standard groove depth corresponding to each groove one by one;

a calibration unit 84 for updating the initial parameter values according to the loss function to determine updated parameter values and to determine a calibrated laser plane equation.

In an embodiment of the present invention, the laser groove depth unit includes:

In an embodiment of the present invention, the laser coordinate module is specifically configured to:

In an embodiment of the present invention, the reference straight line module is specifically configured to:

In the embodiment of the present invention, it is assumed that the laser coordinates of the first reference point are (x _L ^P1 ，y _L ^P1 ) The laser coordinates of the second reference point are (x) _L ^P2 ，y _L ^P2 ) Determining that the reference straight line is:

y=kx+m, wherein,m＝y _L ^P1 -k*x _L ^P1 。

in an embodiment of the present invention, the laser groove depth module is specifically configured to:

In the embodiment of the present invention, the loss function is:

In an embodiment of the present invention, the calibration unit is specifically configured to:

In an embodiment of the present invention, the apparatus further includes:

It should be noted that, the above device may execute the method provided by the embodiment of the present application, and has the corresponding functional modules and beneficial effects of executing the method. Technical details which are not described in detail in the device embodiments may be found in the methods provided in the embodiments of the present application.

In an embodiment of the present invention, a calibration device is provided and applied to a monocular laser calibration system, where the monocular laser calibration system includes a target and a monocular laser measurement device, the target includes a groove area, the groove area includes a plurality of grooves with different depths, the monocular laser measurement device includes a laser and a camera, and laser output by the laser is projected on the target, and the device includes: the laser line image unit is used for acquiring the laser line image of the target acquired by the camera; a laser groove depth unit for determining the laser groove depth of each groove of the groove region according to the laser line image; the loss function unit is used for determining a loss function corresponding to an initial parameter value of a preset laser plane equation according to the laser groove depth of each groove and the standard groove depth corresponding to each groove one by one; and the calibration unit is used for updating the initial parameter value according to the loss function to determine an updated parameter value and determining a calibrated laser plane equation. By arranging a plurality of grooves with different depths in the groove area, constructing a loss function, updating parameter values based on the loss function to determine a calibrated laser plane equation.

Referring to fig. 9 again, fig. 9 is a schematic structural diagram of a monocular laser measuring apparatus according to an embodiment of the present invention;

as shown in fig. 9, the monocular laser measuring device 90 includes, but is not limited to: radio frequency unit 91, network module 92, audio output unit 93, input unit 94, sensor 95, display unit 96, user input unit 97, interface unit 98, memory 99, processor 910, and power source 911, the monocular laser measuring device further includes a camera. It will be appreciated by those skilled in the art that the configuration of the monocular laser measuring device shown in fig. 9 does not constitute a limitation of the monocular laser measuring device, and that the monocular laser measuring device may include more or less components than illustrated, or certain components may be combined, or a different arrangement of components. In an embodiment of the invention, the monocular laser measuring device includes, but is not limited to, a television, a mobile phone, a tablet computer, a notebook computer, a palm computer, a vehicle-mounted terminal, a wearable device, a pedometer and the like.

A processor 910, configured to acquire a laser line image of the target acquired by the camera; determining the laser groove depth of each groove of the groove region according to the laser line image; determining a loss function corresponding to an initial parameter value of a preset laser plane equation according to the laser groove depth of each groove and the standard groove depth corresponding to each groove one by one; and updating the initial parameter value according to the loss function to determine an updated parameter value, and determining a calibrated laser plane equation.

In the embodiment of the invention, the loss function is constructed by arranging the grooves with different depths in the groove region, and the parameter value is updated based on the loss function to determine the calibrated laser plane equation.

It should be understood that, in the embodiment of the present invention, the radio frequency unit 91 may be used for receiving and transmitting signals during the process of receiving and transmitting information or communication, specifically, receiving downlink data from the base station and then processing the received downlink data by the processor 910; and, the uplink data is transmitted to the base station. Typically, the radio frequency unit 91 includes, but is not limited to, an antenna, at least one amplifier, a transceiver, a coupler, a low noise amplifier, a duplexer, and the like. In addition, the radio frequency unit 91 may also communicate with networks and other devices through a wireless communication system.

The monocular laser measurement device 90 provides wireless broadband internet access to the user via the network module 92, such as helping the user to send and receive e-mail, browse web pages, access streaming media, and the like.

The audio output unit 93 may convert audio data received by the radio frequency unit 91 or the network module 92 or stored in the memory 99 into an audio signal and output as sound. Also, the audio output unit 93 may also provide audio output (e.g., a call signal reception sound, a message reception sound, etc.) related to a specific function performed by the monocular laser measuring device 90. The audio output unit 93 includes a speaker, a buzzer, a receiver, and the like.

The input unit 94 is for receiving an audio or video signal. The input unit 94 may include a graphics processor (Graphics Processing Unit, GPU) 941 and a microphone 942, the graphics processor 941 processing a target image of a still picture or video obtained by an image capturing device (e.g., a camera) in a video capturing mode or an image capturing mode. The processed image frames may be displayed on the display unit 96. The image frames processed by the graphics processor 941 may be stored in memory 99 (or other storage medium) or transmitted via the radio frequency unit 91 or the network module 92. Microphone 942 may receive sound and may be capable of processing such sound into audio data. The processed audio data may be converted into a format output that can be transmitted to the mobile communication base station via the radio frequency unit 91 in the case of a telephone call mode.

The monocular laser measurement device 90 also includes at least one sensor 95, such as a light sensor, a motion sensor, and other sensors. Specifically, the light sensor includes an ambient light sensor that can adjust the brightness of the display panel 961 according to the brightness of ambient light, and a proximity sensor that can turn off the display panel 961 and/or the backlight when the monocular laser measurement device 90 is moved to the ear. As one of the motion sensors, the accelerometer sensor can detect the acceleration in all directions (generally three axes), and can detect the gravity and the direction when the accelerometer sensor is stationary, and can be used for identifying the gesture (such as horizontal and vertical screen switching, related games and magnetometer gesture calibration) of the monocular laser measuring equipment, vibration identification related functions (such as pedometer and knocking) and the like; the sensor 95 may further include a fingerprint sensor, a pressure sensor, an iris sensor, a molecular sensor, a gyroscope, a barometer, a hygrometer, a thermometer, an infrared sensor, etc., which are not described herein.

The display unit 96 is used to display information input by a user or information provided to the user. The display unit 96 may include a display panel 961, and the display panel 961 may be configured in the form of a liquid crystal display (Liquid Crystal Display, LCD), an Organic Light-Emitting Diode (OLED), or the like.

The user input unit 97 may be used to receive input numerical or character information and to generate key signal inputs related to user settings and function control of the monocular laser measuring device. Specifically, the user input unit 97 includes a touch panel 971 and other input devices 972. The touch panel 971, also referred to as a touch screen, may collect touch operations thereon or thereabout by a user (e.g., operations of the user on the touch panel 971 or thereabout using any suitable object or accessory such as a finger, stylus, etc.). The touch panel 971 may include two parts, a touch detection device and a touch controller. The touch detection device detects the touch azimuth of a user, detects a signal brought by touch operation and transmits the signal to the touch controller; the touch controller receives touch information from the touch detection device, converts the touch information into touch point coordinates, sends the touch point coordinates to the processor 910, and receives and executes commands sent by the processor 910. In addition, the touch panel 971 may be implemented in various types of resistive, capacitive, infrared, surface acoustic wave, and the like. In addition to the touch panel 971, the user input unit 97 may include other input devices 972. In particular, other input devices 972 may include, but are not limited to, a physical keyboard, function keys (e.g., volume control keys, switch keys, etc.), a trackball, a mouse, and a joystick, which are not described in detail herein.

Further, the touch panel 971 may be overlaid on the display panel 961, and when the touch panel 971 detects a touch operation thereon or thereabout, the touch operation is transmitted to the processor 910 to determine a type of touch event, and the processor 910 then provides a corresponding visual output on the display panel 961 according to the type of touch event. Although in fig. 9, the touch panel 971 and the display panel 961 are two independent components to implement the input and output functions of the monocular laser measuring device, in some embodiments, the touch panel 971 may be integrated with the display panel 961 to implement the input and output functions of the monocular laser measuring device, which is not limited herein.

The interface unit 98 is an interface to which an external device is connected with the monocular laser measuring apparatus 90. For example, the external devices may include a wired or wireless headset port, an external power (or battery charger) port, a wired or wireless data port, a memory card port, a port for connecting a device having an identification module, an audio input/output (I/O) port, a video I/O port, an earphone port, and the like. The interface unit 98 may be used to receive input (e.g., data information, power, etc.) from an external device and transmit the received input to one or more elements within the monocular laser measurement apparatus 90 or may be used to transmit data between the monocular laser measurement apparatus 90 and an external device.

The memory 99 may be used to store software programs as well as various data. The memory 99 may mainly include a storage program area and a storage data area, wherein the storage program area may store an application 991 (such as a sound playing function, an image playing function, etc.) and an operating system 992, etc. required for at least one function; the storage data area may store data (such as audio data, phonebook, etc.) created according to the use of the handset, etc. In addition, memory 99 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other volatile solid-state storage device.

The processor 910 is a control center of the monocular laser measuring apparatus, connects respective parts of the entire monocular laser measuring apparatus using various interfaces and lines, and performs various functions and processes data of the monocular laser measuring apparatus by running or executing software programs and/or modules stored in the memory 99 and calling data stored in the memory 99, thereby performing overall monitoring of the monocular laser measuring apparatus. Processor 910 may include one or more processing units; preferably, the processor 910 may integrate an application processor that primarily handles operating systems, user interfaces, applications, etc., with a modem processor that primarily handles wireless communications. It will be appreciated that the modem processor described above may not be integrated into the processor 910.

The monocular laser measurement device 90 may also include a power supply 911 (e.g., a battery) for powering the various components, and preferably the power supply 911 may be logically connected to the processor 910 by a power management system, such as to perform charge, discharge, and power management functions via the power management system.

In addition, the monocular laser measuring device 90 includes some functional modules, which are not shown, and are not described herein.

Preferably, the embodiment of the present invention further provides a monocular laser measurement device, which includes a processor 910, a memory 99, and a computer program stored in the memory 99 and capable of running on the processor 910, where the computer program when executed by the processor 910 implements each process of the above calibration method embodiment, and the same technical effects can be achieved, and for avoiding repetition, a detailed description is omitted herein.

The embodiment of the invention also provides a computer readable storage medium, on which a computer program is stored, which when executed by one or more processors, implements the processes of the calibration method embodiment described above, and can achieve the same technical effects, so that repetition is avoided, and no further description is provided herein. Wherein the computer readable storage medium is selected from Read-Only Memory (ROM), random access Memory (Random Access Memory, RAM), magnetic disk or optical disk.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation 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 may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The above-described embodiments of the apparatus or device are merely illustrative, in which the unit modules illustrated as separate components may or may not be physically separate, and the components shown as unit modules may or may not be physical units, may be located in one place, or may be distributed over multiple network module units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

From the above description of the embodiments, it will be clear to those skilled in the art that the above-described embodiment method may be implemented by means of software plus a necessary general hardware platform, but of course may also be implemented by means of hardware, but in many cases the former is a preferred embodiment. Based on such understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art in the form of a software product stored in a storage medium (e.g. ROM/RAM, magnetic disk, optical disk) comprising several instructions for causing a terminal (which may be a mobile terminal, a personal computer, a server, or a network device, etc.) to perform the method according to the embodiments or some parts of the embodiments of the present invention.

Finally, it should be noted that: the embodiments described above in connection with the accompanying drawings are only for illustrating the technical aspects of the present invention, and the present invention is not limited to the above-described embodiments, which are only illustrative, but not restrictive; the technical features of the above embodiments or in the different embodiments may also be combined within the idea of the invention, the steps may be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. The utility model provides a calibration method, is applied to monocular laser calibration system, its characterized in that, monocular laser calibration system includes target and monocular laser measuring equipment, the target includes the recess district, the recess district includes a plurality of different degree of depth recesses, monocular laser measuring equipment includes laser instrument, camera, the laser instrument output laser throw in the target, the method includes:

Acquiring a laser line image of the target acquired by the camera;

2. The method of claim 1, wherein determining a laser groove depth for each groove of the groove region from the laser line image comprises:

3. The method of claim 2, wherein determining the laser coordinates of the bottom point of each groove and the reference point based on the pixel coordinates of the bottom point of each groove and the reference point comprises:

4. A method according to claim 3, wherein determining the camera coordinates of the bottom point of each groove and the reference point from the pixel coordinates of the bottom point of each groove and the reference point comprises:

5. The method of claim 4, wherein determining the laser coordinates of the bottom point of each groove and the reference point based on the camera coordinates of the bottom point of each groove and the reference point comprises:

6. The method according to claim 2, wherein determining a reference line corresponding to each groove according to the laser coordinates of the reference point comprises:

7. According to claimThe method of claim 6, wherein the laser coordinates of the first reference point are assumed to be (x _L ^P1 ，y _L ^P1 ) The laser coordinates of the second reference point are (x) _L ^P2 ，y _L ^P2 ) Determining that the reference straight line is:

y=kx+m, wherein,m＝y _L ^P1 -k*x _L ^P1 。

8. the method of claim 7, wherein determining the laser groove depth for each groove based on the reference line for each groove comprises: let the laser groove depth of the ith groove be d _i And determining the depth of the laser groove as follows:

9. The method according to any one of claims 1-8, wherein the loss function is:

10. The method according to any one of claims 1-8, wherein updating the initial parameter value according to the loss function to determine an updated parameter value comprises:

11. The method of claim 10, wherein determining the calibrated laser plane equation comprises:

12. The method according to any one of claims 1-8, further comprising:

13. The utility model provides a calibration device, is applied to monocular laser calibration system, its characterized in that, monocular laser calibration system includes target and monocular laser measuring equipment, the target includes the recess district, the recess district includes the different recess of a plurality of degree of depth, monocular laser measuring equipment includes laser instrument, camera, laser instrument output laser throw in the target, the device includes:

14. A monocular laser measuring apparatus, comprising:

at least one processor; and

a memory communicatively coupled to the at least one processor; wherein,

The memory stores instructions executable by the at least one processor to enable the at least one processor to perform the calibration method of any one of claims 1-12.

15. A monocular laser calibration system, comprising:

a target;

the monocular laser measurement apparatus of claim 14;