CN219802429U

CN219802429U - Optical equipment calibration tool

Info

Publication number: CN219802429U
Application number: CN202320944412.5U
Authority: CN
Inventors: 孙光耀; 王彦良
Original assignee: Beijing Guangyao Youchuang Technology Co ltd
Current assignee: Beijing Jiahe Intelligent Technology Co.,Ltd.
Priority date: 2023-04-24
Filing date: 2023-04-24
Publication date: 2023-10-03
Anticipated expiration: 2033-04-24

Abstract

The utility model discloses an optical equipment calibration tool, which comprises a supporting platform, wherein the supporting platform is provided with a plurality of support plates; a guide rail, the axial direction of which is arranged along the direction towards the target display; the guide rail is connected with the top of the supporting platform; the surface of the target display is provided with a reflecting mirror; the sliding assembly comprises a sliding table, an upright post and an objective table; the upright post is fixedly connected with the top of the sliding table; the objective table is fixedly connected with the upright post; the sliding table is connected with the guide rail in a matched mode. The tool adopts the high-precision guide rail to enable the calibrated optical equipment to move along with the guide rail moving platform on the guide rail in a single-axis manner, the moving direction of the guide rail and the plane of the target display are regulated to be in a relative vertical pose by the aid of the light calibration assembly, and the grating ruler reads and determines the moving distance. Meanwhile, the calibration tool has wide application range, can be compatible with an area array camera and a line scanning camera, is not only used for monocular calibration, but also used for calibrating a binocular system and a multi-ocular system.

Description

Optical equipment calibration tool

Technical Field

The utility model relates to the technical field of optical equipment calibration, in particular to an optical equipment calibration tool with low cost and high positioning precision.

Background

Cameras have important applications in the industry. In production applications, the parameters of the camera need to be calibrated. The camera calibration is used as a necessary basic work for optical application, the precision level of the calibration method directly influences the precision result of the system application, not only relates to basic theoretical research of the calibration method, but also comprises requirements on the engineering level of camera calibration, and is a direct embodiment of the research level of the optical system.

The camera parameter calibration is to realize the mapping between the three-dimensional space point and the two-dimensional pixel point of the camera, namely, the mapping is converted from a well-known world coordinate system to a camera coordinate system and then from the camera coordinate system to an image coordinate system, and because each camera has a certain difference in a fine structure, the camera internal parameter and the camera external parameter need to be calibrated so as to accurately convert the world coordinate system to the image coordinate system. The camera calibration method capable of achieving high-precision calibration in the prior art comprises the following steps: traditional camera calibration methods and active vision camera calibration methods.

Traditional camera calibration method: such as Tsai two-step method, zhangshi calibration method, require high-precision calibration objects and are complex in algorithm. The equipment used for traditional calibration is a calibration plate, and some calibration tools based on the calibration plate are also available.

The active vision camera calibration method comprises the following steps: the active system controls the camera to do specific motion, such as turntable calibration, no calibration object is needed, the algorithm is simple, the robustness is high, the cost is high, and the equipment is expensive.

Calibrating a turntable, namely respectively converting a first coordinate point under a standard coordinate system to a second coordinate point under a camera coordinate system under different turntable postures to obtain a coordinate point set; respectively calculating distance errors between the first coordinate point and each coordinate point in the coordinate point set to generate a distance error set; obtaining a target loss function of a turntable calibration algorithm according to the distance error set; according to the target loss function, the turntable calibration algorithm is optimized, the point cloud precision of the characteristic points after each rotation of the current rotating shaft is improved, and the splicing precision is higher as the rotating shaft is more.

It can be seen that based on the conventional calibration method: for camera calibration for large-view-field application, in principle, the calibration precision gradually decreases from the center to the edge, and in practical high-precision imaging and measurement application, the calibration precision is limited and cannot meet the requirements.

Calibrating a three-axis turntable: in theory, the turntable calibration stepping based on the three-axis turntable is fine enough, the global precision of the calibrated camera can be ensured, but the calibration of each pixel is realized by the dot matrix calibration method, the efficiency is quite low, and the actual scale calibration requirement cannot be met. The turntable calibration is dot matrix vector calibration, and if each pixel is calibrated, the efficiency is very low, a high-precision turntable is required to be used, and the cost is very high.

In order to solve the problems, a new calibration algorithm is provided, the calibration algorithm can perform global vector calibration on calibrated equipment, so that the global error distribution of the calibrated result is consistent, the mean value of pixel position errors is 0, and the theoretical mean square error is less than 1/1000 pixel. However, the calibration algorithm has extremely strict requirements on the acquired images, two groups of images are required to be acquired at two positions respectively, and the vector directions of the two positions are required to be absolutely perpendicular to the plane of the target display, which directly influences the calibration accuracy.

Therefore, how to provide a calibration tool can ensure that the vector directions of two positions are absolutely perpendicular to the plane of the target display when two sets of images are respectively acquired at two positions is a technical problem which is urgent to be solved by a person skilled in the art.

Disclosure of Invention

The utility model provides an optical equipment calibration tool.

The utility model provides the following scheme:

an optical device calibration tooling, comprising:

a support platform;

a guide rail, the axial direction of which is arranged along the direction towards the target display; the guide rail is connected with the top of the supporting platform; the surface of the target display is provided with a reflecting mirror;

the sliding assembly comprises a sliding table, an upright post and an objective table; the upright post is fixedly connected with the top of the sliding table; the objective table is fixedly connected with the upright post; the sliding table is connected with the guide rail in a matched manner; the sliding table is used for bearing optical equipment to be calibrated;

the light calibration assembly comprises a laser generation assembly and a first posture adjustment assembly, the laser generation assembly is used for emitting laser rays towards the target display, and the first posture adjustment assembly is used for adjusting the posture of the laser generation assembly according to the displacement condition of sampling points of the laser rays in the sliding process of the sliding assembly along the guide rail, so that the laser rays are parallel to the moving direction of the sliding assembly;

a second gesture adjustment assembly, the second gesture adjustment assembly coupled to the target display; the second posture adjusting component is used for adjusting the posture of the target display to enable the reflecting point of the laser line on the reflecting mirror to coincide with the emitting opening of the laser line.

Preferably: the device also comprises a grating ruler and a grating ruler digital display meter, wherein the grating ruler is arranged along the axial direction of the guide rail and is connected with the guide rail.

Preferably: the sliding table is characterized by further comprising a moving driving assembly, wherein the moving driving assembly is connected with the sliding table and used for driving the sliding table to slide along the guide rail.

Preferably: the mobile drive assembly, the first attitude adjustment assembly, and the second attitude adjustment assembly each include an automatic drive system.

Preferably: the supporting platform comprises a supporting frame, a mounting plate is arranged at the top of the supporting frame, and the guide rail is connected with the mounting plate through a plurality of guide rail supporting pieces; and the guide rail supports are used for realizing the adjustment of the horizontal state of the guide rail.

Preferably: the bottom of support frame is provided with the runner and a plurality of lower margin.

Preferably: the guide rail support comprises a screw, three nuts and two gaskets.

Preferably: the first gesture adjusting component is connected with the objective table, the target display is used for displaying a cross target, the laser generating component comprises a laser, the laser is used for emitting laser lines to the cross target, and the sampling point is a laser point located at the center of the cross target.

Preferably: the stand column is positioned between the support and the target display; the first posture adjusting component is connected with the bracket; the laser generating assembly comprises an autocollimator, a through hole is arranged on the upright post and positioned on a light-emitting path of the autocollimator, and the through hole is used for detachably installing a receiving end; the sampling point is located at the laser point on the receiving end.

Preferably: the auto-collimator is used for emitting parallel laser lines parallel to the moving direction of the guide rail towards the reflecting mirror, so that the parallel laser lines are projected onto the reflecting mirror through the through hole after the receiving end is removed.

According to the specific embodiment provided by the utility model, the utility model discloses the following technical effects:

according to the optical equipment calibration tool, the high-precision guide rail is adopted in the tool, so that the calibrated optical equipment moves along with the guide rail moving platform on the guide rail in a single-axis mode, the guide rail moving direction and the target display plane are regulated to be relatively vertical by means of the light calibration assembly in an auxiliary mode, and the grating ruler reads and determines the moving distance. Meanwhile, the calibration tool has wide application range, can be compatible with an area array camera and a line scanning camera, is not only used for monocular calibration, but also used for calibrating a binocular system and a multi-ocular system.

Of course, it is not necessary for any one product to practice the utility model to achieve all of the advantages set forth above at the same time.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a first structure of an optical device calibration tool (a laser generating component is a laser) according to an embodiment of the present utility model;

FIG. 2 is another first structural schematic diagram of an optical device calibration tool (the laser generating component is a laser) according to an embodiment of the present utility model;

fig. 3 is a second schematic structural diagram of an optical device calibration tool (the laser generating component is an auto-collimator) according to an embodiment of the present utility model.

In the figure: the optical equipment 3 to be calibrated comprises a supporting platform 11, a guide rail 12, a sliding table 13, a stand column 14, an objective table 15, a laser generating assembly 16, a first posture adjusting assembly 17, a grating scale 18, a moving driving assembly 19, a guide rail supporting piece 110, a rotating wheel 111, a ground leg 112, a bracket 113, a receiving end 114, a target display 21, a reflecting mirror 22, a second posture adjusting assembly 23 and the optical equipment 3 to be calibrated.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which are derived by a person skilled in the art based on the embodiments of the utility model, fall within the scope of protection of the utility model.

Examples

Referring to fig. 1, fig. 2, and fig. 3, an optical device calibration tool provided in an embodiment of the present utility model, as shown in fig. 1, fig. 2, and fig. 3, the calibration tool may include:

a support platform 1;

a guide rail 12, the axial direction of the guide rail 12 being arranged in a direction toward the targeting display 21; the guide rail 12 is connected with the top of the supporting platform 1; the surface of the target display 21 is provided with a mirror 22;

a slide assembly comprising a slide table 13, a column 14 and a stage 15; the upright post 14 is fixedly connected with the top of the sliding table 13; the objective table 15 is fixedly connected with the upright post 14; the sliding table 13 is connected with the guide rail 12 in a matched manner; the sliding table 13 is used for bearing the optical equipment 3 to be calibrated;

a light calibration assembly, the light calibration assembly including a laser generating assembly 16 and a first posture adjustment assembly 17, the laser generating assembly 16 being configured to emit a laser line toward the target display 21, the first posture adjustment assembly 17 being configured to adjust a posture of the laser generating assembly 16 according to a displacement of a sampling point of the laser line during a sliding process of the sliding assembly along the guide rail 12, so that the laser line is parallel to a moving direction of the sliding assembly;

a second attitude adjustment assembly 23, said second attitude adjustment assembly 23 being connected to said target display 21; the second posture adjustment component 23 is configured to adjust the posture of the target display 21, so that the reflecting point on the reflecting mirror 22 coincides with the emission opening of the laser line.

According to the optical equipment calibration tool provided by the embodiment of the utility model, the movement direction of the objective table 15 and the surface of the target display 21 can be kept vertical all the time in an auxiliary manner through the laser rays emitted by the laser generating assembly 16. Therefore, when the optical device 3 to be calibrated acquires two groups of images at two positions, the vector direction of the two positions and the plane of the target display 21 can reach an absolute vertical state after the optical device 3 to be calibrated moves along with the two positions on the guide rail of the objective table 15, and the aim of improving the calibration precision is fulfilled.

In order to accurately obtain the linear motion distance of the carrying platform on the guide rail, the embodiment of the utility model can also provide the grating scale 18 and the grating scale digital display table, wherein the long direction of the grating scale 18 is arranged along the axial direction of the guide rail 12 and is connected with the guide rail 12.

In order to facilitate driving the sliding table 13 to move relative to the guide rail, the embodiment of the present utility model may provide a movement driving assembly 19, where the movement driving assembly 19 is connected to the sliding table 13, and the movement driving assembly 19 is used to drive the sliding table 13 to slide along the guide rail.

To further increase the automation of the tool, embodiments of the present utility model may further provide that the movement driving assembly 19, the first posture adjustment assembly 17 and the second posture adjustment assembly 23 each comprise an automatic driving system.

It can be understood that the support platform 1 provided by the embodiment of the present utility model is used as a support structure of each component, and in practical application, the support platform can be configured according to field requirements. For example, in one implementation, as shown in fig. 1 and 2, the embodiment of the present utility model may provide that the support platform 1 includes a support frame, where a mounting plate is disposed on top of the support frame, and the guide rail 12 is connected to the mounting plate through a plurality of guide rail supports 110; a plurality of the rail supports 110 are used to achieve adjustment of the horizontal state of the rail 12.

In order to facilitate the whole movement of the tool, the embodiment of the utility model can also provide that the bottom of the supporting frame is provided with a rotating wheel 111 and a plurality of feet 112. The whole frock of can promoting to corresponding position according to the demand through runner 111 that provides, can fix through lower margin 112 after putting in place, guarantees that the frock is whole steady.

The guide rail supports 110 provided by the embodiment of the present utility model can realize adjustment of the horizontal state of the guide rail 12, and further, the embodiment of the present utility model may further provide that the guide rail supports 110 include one screw, three nuts, and two gaskets.

It can be understood that the laser emitted by the laser generating assembly 16 according to the embodiment of the present utility model may be used as an auxiliary light when the moving direction of the guide rail 12 is perpendicular to the plane of the target display 21, and the method for implementing the perpendicular adjustment may be determined according to the installation position and type of the laser generating assembly 16, for example, the embodiment of the present utility model may provide two different types of laser generating assemblies 16 and two corresponding different installation manners, which may both implement the perpendicular adjustment.

Specifically, in one implementation, the first posture adjustment assembly 17 may be provided and connected to the stage 15, the target display 21 is configured to display a cross target, the laser generating assembly 16 includes a laser, the laser is configured to emit a laser line to the cross target, and the sampling point is a laser point located at a center position of the cross target.

The tool has the remarkable effects that a calibration plate is omitted, a grating image projected by the target display is used as the calibration plate, and the tool is suitable for high-precision calibration under various medium and large visual field ranges (the visual field range is smaller than the display area of the target display). The whole calibration tool is debugged by the method, so that the relative vertical precision of the moving direction of the guide rail and the target display screen can reach a very high level. After the debugging is finished, in the subsequent calibration process, the calibration of various optical components can be carried out by only replacing the calibrated equipment on the tool.

The method for using the tool calibration in this way is described in detail below.

The calibration tool built for high-precision calibration comprises the following components: the support frame with the belt pulley with the foot 112, the guide rail 12, the grating ruler 18, a grating ruler digital display meter, a laser, a target display 21, a first posture adjusting component 17, a second posture adjusting component 23 and the like.

1. The support frame is placed in a suitable position directly in front of the target display 21, in which position the display range of the target display 21 can cover the entire field of view of all the calibrated devices.

2. The support frame ground leg 112 is adjusted so that the whole calibration tool cannot incline or shake slightly in the calibration process. The method comprises the following steps: firstly, two feet 112 on a diagonal line are adjusted, and the two feet 112 support the whole tool and have almost the same stress; the two legs 112 of the other diagonal are readjusted.

3. The posture of the guide rail 12 is adjusted by adjusting the guide rail support 110 so that the guide rail 12 is in a horizontal state. 8 rail supports 110 are used, each rail support 110 consisting of 1 screw, 3 nuts, 2 shims.

The above adjustment is to make the calibrated device move uniaxially on the guide rail 12 along with the sliding table 13, without any movement in other directions.

4. The moving direction of the guide rail 12 and the plane of the target display 21 are adjusted to a relative vertical pose by the aid of a laser.

Firstly, adjusting the parallelism of the laser line and the moving direction of the guide rail 12: the cross target is displayed on the target display 21, the line width of the target is 1 pixel, and the light spot diameter is not larger than the width of a single pixel on the target display 21 when the laser is at a distance of 2110 meters from the target display. The laser is activated to strike a laser spot on the screen, moving the position of the cross target center on the target display 21 to the laser spot as a sampling point. When the laser is moved on the guide rail 12 and the displacement direction of the laser spot on the target display 21 is observed, if the laser spot is moved in a certain direction, the horizontal pitch angle of the laser is adjusted by the first attitude adjusting unit to move the laser spot in the direction, and the above operation is repeated until the displacement of the laser spot is not observed, and the accuracy is about 20.63 "(10 m).

And then adjusting the perpendicularity of the laser line and the plane of the target display 21: the light spot of the laser on the plane of the target display 21 is reflected by the surface of the screen or the mirror 22 attached to the screen, and the posture of the display is adjusted by the second posture adjusting component 23 (the second posture adjusting component 23 may be a self-contained bracket 113 or a customized bracket 113 capable of being finely tuned), so that the reflecting point coincides with the laser emitting opening, and the laser line is relatively perpendicular to the plane of the target display 21.

5. After the position and the posture of the calibration tool are adjusted, starting to calibrate, shooting a group of grating images at two positions respectively, recording the moving distance of the camera through grating reading, and transmitting data to a computer provided with calibration software to finish calibration.

In order to further improve the calibration accuracy of the tool provided by the embodiment of the present utility model, in another implementation manner, as shown in fig. 3, the embodiment of the present utility model may further provide a bracket 113 connected to the support platform 1, where the upright 14 is located between the bracket 113 and the target display 21; the first posture adjustment assembly 17 is connected with the bracket 113; the laser generating assembly 16 includes an autocollimator, and a through hole is arranged on the upright post 14 and positioned on the light emitting path of the autocollimator, and the through hole is used for detachably mounting the receiving end 114; the sampling point is located at the laser point on the receiving end 114.

Further, the auto-collimator is configured to emit parallel laser lines parallel to the moving direction of the guide rail 12 toward the reflecting mirror 22, so that the parallel laser lines are projected onto the reflecting mirror 22 through the through hole after the receiving end 114 is removed.

Further reductions in systematic errors can be achieved using autocollimators instead of lasers.

Instead of using a laser, an autocollimator may be used to assist in adjusting the direction of movement of the rail 12 to be relatively perpendicular to the plane of the target display 21. The method comprises the following steps:

after each device is installed, starting to debug the tool:

step 1, the autocollimator is adjusted so that the direction of the emitted parallel light is parallel to the direction of movement of the guide rail 12. Opening the collimator to ensure that the receiving end 114 can receive the parallel light emitted by the auto-collimator, taking a laser point on the receiving end 114 as a sampling point, and reading the reading of the receiving end 114; the guide rail 12 is slowly moved, the receiving end 114 is continuously observed to read in the moving process, the number of the receiving end 114 can be read in the full stroke range of the guide rail 12, and if the number exceeds the number, the posture of the auto-collimator is finely adjusted through the first posture adjusting component 17. In the process that the receiving end 114 moves along with the guide rail 12, if the reading changes, the first posture adjusting component 17 of the collimator is used for adjusting the posture of the collimator according to the change trend until the reading does not change any more when the guide rail 12 is moved, and at the moment, the parallel light emitted by the auto-collimator is parallel to the moving direction of the guide rail 12.

If the receiving end 114 moves along the positive Z-axis direction, the reading x-value of the receiving end 114 increases and the reading y-value of the receiving end decreases, the pose of the auto-collimator is adjusted towards the positive x-axis direction and the negative y-axis direction of the receiving end 114, and the amplitude adjustment vision value variation is determined. The adjustment direction is opposite to the above steps when the receiving end moves along the negative Z-axis direction.

The above steps are repeated a number of times with less variation in the receiver readings until no more variation in the readings occurs when the rail 12 is moved.

And 2, removing the receiving end 114 arranged on the upright post 14 of the guide rail 12 (taking care not to change the pose of the guide rail 12 in the removing process), enabling the parallel light emitted by the auto-collimator to directly strike on the reflecting mirror 22 (the included angle between the reflecting direction of the reflecting mirror 22 and the installation plane is 90+/-0.01 ℃) on the target display 21, and adjusting the pose of the target display 21 by using the second pose adjusting component 23 according to the reading of the auto-collimator, so that the parallel light emitted by the collimator coincides with the received parallel light, and the direction of the collimator is perpendicular to the plane of the target display 21.

The guide rail 12, the laser adjusting platform and the display two-dimensional adjustment are changed into motor control, so that one-key calibration of the whole process is realized.

The laser line adjustment is carried out by using a laser or an autocollimator, after human eyes are required to identify and judge the displacement direction of the laser, the pose of the laser can be manually adjusted, and the two-dimensional rotation of the laser and the target display 21 can be controlled by adding a machine vision identification laser point and a PLC, so that one-key calibration from tool debugging to image acquisition to calibration result acquisition is finally realized. The laser adjustment used enables a final accuracy of about 20.63 "(10 m), with a resolution of 5 μm for the grating scale 18, and the overall system accuracy can be further improved if a higher accuracy autocollimator and grating scale 18 are used.

In a word, the optical equipment calibration tool provided by the utility model adopts the high-precision guide rail to enable the calibrated optical equipment to move along with the guide rail moving platform on the guide rail in a single-axis manner, the guide rail moving direction and the target display plane are regulated to be in a relatively vertical pose by the aid of the light calibration component, and the grating ruler reads and determines the moving distance. Meanwhile, the calibration tool has wide application range, can be compatible with an area array camera and a line scanning camera, is not only used for monocular calibration, but also used for calibrating a binocular system and a multi-ocular system.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, 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 foregoing description is only of the preferred embodiments of the present utility model and is not intended to limit the scope of the present utility model. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model are included in the protection scope of the present utility model.

Claims

1. An optical device calibration tool, comprising:

a support platform;

2. The optical equipment calibration fixture of claim 1, further comprising a grating scale and a grating scale digital display meter, wherein the length direction of the grating scale is arranged along the axial direction of the guide rail and is connected with the guide rail.

3. The optical device calibration tooling of claim 1, further comprising a movement drive assembly coupled to the slide table, the movement drive assembly configured to drive the slide table to slide along the guide rail.

4. An optical device calibration fixture as recited in claim 3, wherein the mobile drive assembly, the first attitude adjustment assembly, and the second attitude adjustment assembly each comprise an automated drive system.

5. The optical equipment calibration fixture according to claim 1, wherein the support platform comprises a support frame, a mounting plate is arranged on the top of the support frame, and the guide rail is connected with the mounting plate through a plurality of guide rail supporting pieces; and the guide rail supports are used for realizing the adjustment of the horizontal state of the guide rail.

6. The optical equipment calibration fixture of claim 5, wherein the bottom of the support frame is provided with a rotating wheel and a plurality of feet.

7. The optical device calibration fixture of claim 5, wherein the rail support comprises one screw, three nuts, and two shims.

8. The optical device calibration tooling of claim 5, wherein the first attitude adjustment assembly is coupled to the stage, the target display is configured to display a cross target, the laser generation assembly comprises a laser configured to emit a laser line toward the cross target, and the sampling point is a laser point located at a center position of the cross target.

9. The optical device calibration tooling of claim 1, further comprising a bracket coupled to the support platform, the post being positioned between the bracket and the target display; the first posture adjusting component is connected with the bracket; the laser generating assembly comprises an autocollimator, a through hole is arranged on the upright post and positioned on a light-emitting path of the autocollimator, and the through hole is used for detachably installing a receiving end; the sampling point is located at the laser point on the receiving end.

10. The optical device calibration fixture of claim 9, wherein the auto-collimator is configured to emit parallel laser lines parallel to the moving direction of the guide rail toward the mirror, such that the parallel laser lines are projected onto the mirror through the through hole after the receiving end is removed.