CN116503493B - Multi-camera calibration method, high-precision equipment and computer readable storage medium - Google Patents

Multi-camera calibration method, high-precision equipment and computer readable storage medium Download PDF

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CN116503493B
CN116503493B CN202310766913.3A CN202310766913A CN116503493B CN 116503493 B CN116503493 B CN 116503493B CN 202310766913 A CN202310766913 A CN 202310766913A CN 116503493 B CN116503493 B CN 116503493B
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camera
information
cameras
installation
calibration
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CN116503493A (en
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安宁
徐成
李义
毕海
田德天
王玉
梁振廷
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/80—Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/70—Determining position or orientation of objects or cameras
    • G06T7/73—Determining position or orientation of objects or cameras using feature-based methods

Abstract

The application relates to the technical field of high-precision equipment, and particularly provides a multi-camera calibration method, high-precision equipment and a computer readable storage medium, wherein the method comprises the following steps: s1, controlling a driving assembly to drive a calibration plate to move along the X-axis direction or the Y-axis direction, acquiring first image information of each camera, and calculating installation deflection angle information of the corresponding camera according to the first image information; s2, controlling the driving assembly to drive the calibration plate to move along the Y axis based on the preset interval so that the calibration plate sequentially enters the camera fields of all cameras, acquiring second image information of each camera, and calculating installation deviation information among the cameras according to the second image information, the installation deflection angle information and the preset interval; s3, determining pose relations among the cameras based on the installation deflection angle information and the installation deviation information; the method can reduce the calibration cost of the multi-camera calibration method, simplify the calculation process and improve the calibration precision of the multi-camera calibration method.

Description

Multi-camera calibration method, high-precision equipment and computer readable storage medium
Technical Field
The application relates to the technical field of high-precision equipment, in particular to a multi-camera calibration method, high-precision equipment and a computer readable storage medium.
Background
High-precision equipment such as an ink-jet printer, a micro light-emitting diode mass transfer device and the like comprises a workbench, a bottom shaft of a moving platform, a moving shaft of a gantry beam and a Z-direction moving shaft, and after a substrate is sliced to the workbench, an offset angle possibly exists between the substrate and the moving shaft of the gantry beam, and the offset angle can influence the working precision of the high-precision equipment, so that the substrate is required to be calibrated by utilizing image information acquired by a plurality of cameras. Because the size of the substrate is large and the camera view range of a single camera is small, there is no overlapping view between the cameras, so before calibrating the substrate, the cameras need to be calibrated first. The prior art performs multi-camera calibration by any one of the following modes: 1. the multi-camera calibration is carried out through an external auxiliary system or an auxiliary camera, for example, patent document CN1107644759 discloses a multi-camera calibration method without overlapping view fields, the calibration method carries out multi-camera calibration by utilizing an external double theodolite three-coordinate measurement system, for example, patent document CN112598749 discloses a large-scene non-common view multi-camera calibration method, and the calibration method carries out multi-camera calibration by utilizing an external pan-tilt camera; 2. patent document CN114792344a discloses a multi-camera position calibration method, which comprises moving a large calibration plate to make a plurality of characteristic regions on the large calibration plate respectively located in camera fields of view of a plurality of cameras, calibrating internal parameters and external parameters of each camera by utilizing the characteristic regions in the camera fields of view of each camera, and obtaining a conversion matrix of a camera coordinate system and a world coordinate system of each camera according to the internal parameters and the external parameters of each camera, thereby realizing calibration of the plurality of cameras. The multi-camera calibration method corresponding to the mode 1 has the conditions of high calibration cost, complex and fussy calculation process caused by the need of an external auxiliary system or an auxiliary camera. Because the large calibration plate can generate geometric errors during manufacturing, the geometric errors can cause calibration errors during calibrating internal parameters and external parameters of the cameras, and the installation deviation of a single camera is not considered during calibrating a plurality of cameras, the multi-camera calibration method corresponding to the mode 2 has the problem that the calibration precision is poor due to the geometric errors and the calibration errors and the installation deviation of the single camera is not considered, so that the calibration precision of the substrate is affected.
In view of the above problems, no effective technical solution is currently available.
Disclosure of Invention
The application aims to provide a multi-camera calibration method, equipment and a storage medium, which can effectively solve the problems of high calibration cost, complex and complicated calculation process of the multi-camera calibration method caused by the need of an external auxiliary system or an auxiliary camera and the problem of poor calibration precision caused by the occurrence of geometric errors and calibration errors and the lack of consideration of the installation deviation of a single camera.
In a first aspect, the present application provides a multi-camera calibration method, applied in a multi-camera calibration system, the multi-camera calibration system includes a calibration plate, a driving assembly and a plurality of cameras, the plurality of cameras are installed along a Y-axis direction, the camera fields of vision of the plurality of cameras are not coincident with each other, the calibration plate is connected with the driving assembly, the driving assembly is used for driving the calibration plate to move along an X-axis direction or a Y-axis direction, and the multi-camera calibration method includes the following steps:
s1, controlling a driving assembly to drive a calibration plate to move along the X-axis direction or the Y-axis direction, acquiring first image information of each camera, and calculating installation deflection angle information of a corresponding camera according to the first image information, wherein the first image information comprises at least two images of the corresponding camera moving in a camera view of the calibration plate;
S2, controlling the driving assembly to drive the calibration plate to move along the Y axis based on the preset interval so that the calibration plate sequentially enters the camera vision fields of all cameras, acquiring second image information of each camera, and calculating installation deviation information among the plurality of cameras according to the second image information, the installation deflection angle information and the preset interval, wherein the second image information comprises images which appear in the camera vision fields of the corresponding cameras when the corresponding cameras move according to the preset interval relative to the calibration plate;
and S3, determining pose relations among the cameras based on the installation deflection angle information and the installation deviation information so as to calibrate all the cameras.
According to the multi-camera calibration method provided by the application, the installation deflection angle information of the corresponding camera is calculated according to the first image information, the installation deflection angle information and the installation deviation information among the plurality of cameras are calculated according to the second image information, the installation deflection angle information and the preset distance, and finally the pose relation among the plurality of cameras is determined based on the installation deflection angle information and the installation deviation information so as to calibrate all the cameras.
Optionally, the calibration plate is provided with a feature area, and step S1 includes:
s11, controlling a driving assembly to drive the calibration plate to move along the X-axis direction or the Y-axis direction, and acquiring first image information of each camera;
s12, respectively acquiring first position information and second position information according to the first image information, wherein the first position information is the position of the characteristic region in the camera coordinate system of one image, and the second position information is the position of the characteristic region in the camera coordinate system of the other image;
s13, calculating the installation deflection angle information of the corresponding camera according to the first position information and the second position information.
Optionally, step S12 includes the steps of:
s121, repeatedly executing step S11 to acquire a plurality of first image information about each camera;
s122, acquiring a plurality of groups of first position information and second position information according to the plurality of first image information;
step S13 includes the steps of:
s131, calculating initial installation angle information according to the first position information and the corresponding second position information, and taking an average value of all the initial installation angle information as installation deflection angle information of the camera.
According to the technical scheme, the first image information is acquired for a plurality of times, the initial installation angle information corresponding to each first image information is calculated respectively, and then the average value of the initial installation angle information is used as the installation deflection angle information of the camera.
Optionally, the calculation formula of step S13 is as follows:
;
wherein Δθ represents the mounting deflection angle information, (x) 1 ，y 1 ) Representing the first position information, (x) 2 ，y 2 ) Representing second location information.
Optionally, the installation deviation information includes X-direction deviation information and Y-direction deviation information, the preset spacing is determined by measurement of a measuring tool, and step S2 includes the steps of:
s21, controlling the driving assembly to drive the calibration plate to move along the Y axis based on the preset interval so that the calibration plate sequentially enters the camera fields of view of the cameras, and acquiring second image information about each camera;
s22, acquiring third position information and quadrant information of the corresponding camera based on each piece of second image information, wherein the third position information is the position of the characteristic region in the camera coordinate system of the corresponding camera, and the quadrant information is the quadrant of the characteristic region in the camera coordinate system of the corresponding camera;
s23, calculating X-axis deviation information of the feature area in a corresponding camera coordinate system according to each third position information, and calculating X-direction deviation information among cameras according to the X-axis deviation information and corresponding quadrant information;
s24, calculating Y-direction deviation information among the cameras according to the third position information, the corresponding quadrant information and the preset distance.
Optionally, step S1 further includes a step performed after step S13:
s14, acquiring moving pixel distance information of a feature area in a camera view according to the first image information and actual movement amount information of a calibration plate based on a measuring tool, and calculating unit pixel information of the camera according to the moving pixel distance information and the actual movement amount information;
the step of calculating X-direction deviation information between each camera according to the X-axis deviation information and the corresponding quadrant information comprises the following steps:
calculating X-direction deviation information among cameras according to the X-axis deviation information, the corresponding quadrant information and the unit pixel information;
step S24 includes:
s241, calculating Y-direction deviation information among cameras according to the third position information, the corresponding quadrant information, the preset distance and the unit pixel information.
Optionally, the steps between step S2 and step S3 further include:
s4, repeatedly executing the step S1 and the step S2 to obtain a plurality of first deviation information groups and a plurality of second deviation information groups, and determining target installation deflection angle information and target installation deviation information according to the first deviation information groups and the corresponding second deviation information groups, wherein the first deviation information groups comprise installation deflection angle information and installation deviation information calculated based on data measured by a grating ruler, and the second deviation information groups comprise installation deflection angle information and installation deviation information calculated based on data measured by a laser interferometer;
The step S3 comprises the following steps:
s31, determining pose relations among the cameras based on the target installation deflection angle information and the target installation deviation information so as to calibrate all the cameras.
The technical scheme is equivalent to the calibration of the installation deflection angle information and the installation deviation information by using the grating ruler and the laser interferometer, so that the calculation accuracy of the installation deflection angle information and the installation deviation information is effectively improved, and the calibration accuracy of the multi-camera calibration method is further effectively improved.
Optionally, the drive assembly includes motion platform lower extreme and longmen crossbeam motion axle, and the demarcation board demountable installation is on motion platform lower extreme, and motion platform lower extreme is used for driving the demarcation board and removes along X axis direction, is equipped with L type mounting bracket on the longmen crossbeam motion axle, and demarcation board demountable installation keeps away from the one end of longmen crossbeam motion axle at L type mounting bracket, and longmen crossbeam motion axle is used for driving the demarcation board and removes along Y axis direction.
In a second aspect, the present application also provides a high precision apparatus comprising a multi-camera calibration system for performing the multi-camera calibration method as provided in the first aspect above.
According to the high-precision equipment provided by the application, the installation deflection angle information of the corresponding cameras is calculated according to the first image information, the installation deflection angle information between the plurality of cameras is calculated according to the second image information, and finally the pose relation between the plurality of cameras is determined based on the installation deflection angle information and the installation deflection information so as to calibrate all the cameras.
In a third aspect, the present application provides a computer readable storage medium having stored thereon a computer program which when executed by a processor performs steps in a method as provided in the first aspect above.
As can be seen from the above, the multi-camera calibration method, the high-precision equipment and the computer readable storage medium provided by the application are characterized in that the installation deflection angle information of the corresponding camera is calculated according to the first image information, the installation deflection angle information and the preset distance are calculated according to the second image information, and finally the pose relation between the plurality of cameras is determined based on the installation deflection angle information and the installation deflection information, so as to calibrate all the cameras.
Drawings
Fig. 1 is a flowchart of a multi-camera calibration method according to an embodiment of the present application.
Fig. 2 is a schematic top view structure of a multi-camera calibration system according to an embodiment of the present application.
Fig. 3 is a schematic diagram of first image information of a driving assembly driving a calibration plate to move along an X-axis direction according to an embodiment of the present application.
Fig. 4 is a schematic diagram of first image information of a driving assembly driving a calibration plate to move along a Y-axis direction according to an embodiment of the present application.
Fig. 5 is a schematic diagram of a calibration plate provided by an embodiment of the present application moving from a second quadrant of a first camera to a first quadrant of the second camera along a Y-axis direction.
Fig. 6 is a schematic diagram of a calibration plate provided by an embodiment of the present application moving from a second quadrant of a first camera to a second quadrant of the second camera along a Y-axis direction.
Fig. 7 is a schematic diagram of a calibration plate provided by an embodiment of the present application moving from a second quadrant of a first camera to a third quadrant of the second camera along a Y-axis direction.
Fig. 8 is a schematic diagram of a calibration plate provided by an embodiment of the present application moving from a second quadrant of a first camera to a fourth quadrant of the second camera along a Y-axis direction.
Reference numerals: 1. a camera; 2. a camera mounting rack; 3. a gantry beam movement axis; 4. a work table; 5. a calibration plate; 6. a feature region; 7. l-shaped mounting frame.
Detailed Description
The following description of the embodiments of the present application 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 application, but not all embodiments. The components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by a person skilled in the art without making any inventive effort, are intended to be within the scope of the present application.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only to distinguish the description, and are not to be construed as indicating or implying relative importance.
1-8, the present application provides a multi-camera calibration method, which is applied in a multi-camera calibration system, the multi-camera calibration system includes a calibration plate 5, a driving assembly and a plurality of cameras 1, the plurality of cameras 1 are installed along the Y-axis direction, the camera fields of vision of the plurality of cameras 1 are not coincident with each other, the calibration plate 5 is connected with the driving assembly, the driving assembly is used for driving the calibration plate 5 to move along the X-axis direction or the Y-axis direction, and the multi-camera calibration method includes the following steps:
s1, controlling a driving assembly to drive a calibration plate 5 to move along the X-axis direction or the Y-axis direction, acquiring first image information of each camera 1, and calculating installation deflection angle information of the corresponding camera 1 according to the first image information, wherein the first image information comprises at least two images of the corresponding camera 1 moving in a camera view of the calibration plate 5;
s2, controlling the driving assembly to drive the calibration plate 5 to move along the Y axis based on the preset interval so that the calibration plate 5 sequentially enters the camera vision fields of all the cameras 1, acquiring second image information of each camera 1, and calculating installation deviation information among the plurality of cameras 1 according to the second image information, the installation deflection angle information and the preset interval, wherein the second image information comprises images which appear in the camera vision fields of the corresponding cameras 1 when the calibration plate 5 moves according to the preset interval;
And S3, determining pose relations among the cameras 1 based on the installation deflection angle information and the installation deviation information so as to calibrate all the cameras 1.
The multi-camera calibration system comprises a calibration plate 5, a driving assembly and a plurality of cameras 1, wherein the calibration plate 5 is a plate which needs to be used when multi-camera calibration is carried out, the size of the calibration plate 5 of the embodiment is smaller than that of a large calibration plate used in the existing multi-camera calibration mode, the plurality of cameras 1 of the embodiment are all cameras 1 with the same model and specification, the plurality of cameras 1 of the embodiment are installed along the Y-axis direction, specifically, the plurality of cameras 1 are all installed on a camera installation frame 2, the camera installation frame 2 extends along the Y-axis direction, the camera fields of the plurality of cameras 1 are not overlapped with each other, the calibration plate 5 is connected with the driving assembly, and the driving assembly can be an assembly which can drive the calibration plate 5 to move along the X-axis direction or the Y-axis direction, such as an electric driving mechanism and the like.
The installation deflection angle information in step S1 is an installation deflection angle of the camera 1, and the installation deflection angle information can reflect whether the installation of the camera 1 has deviation, specifically, if a camera coordinate system corresponding to the camera 1 is parallel to an XOY plane coordinate system (coordinate system corresponding to the XOY plane), it indicates that the installation of the camera 1 has no deviation, and the installation deflection angle information at this time is 0; if the camera coordinate system corresponding to the camera 1 is not parallel to the XOY plane coordinate system, it indicates that there is a deviation in the mounting of the camera 1, and the mounting deflection angle information at this time is not 0. The first image information includes at least two images of the corresponding camera 1 moving in the camera view of the calibration plate 5, since the camera view of the plurality of cameras 1 do not coincide with each other, the calibration plate 5 of this embodiment only appears in the camera view of one of the cameras 1 at the same time, that is, the calibration plate 5 of this embodiment does not appear in the camera view of the plurality of cameras 1 at the same time, step S1 corresponds to moving the calibration plate 5 in the X-axis direction or the Y-axis direction in the camera view of each of the cameras 1, and since the number of cameras 1 is plural, the number of the first image information of this embodiment is plural, and the first image information includes at least an image before the calibration plate 5 starts moving in the camera view of the corresponding camera or when the calibration plate 5 enters the camera view of the corresponding camera, and an image after the calibration plate 5 stops moving in the camera view thereof or before the calibration plate 5 leaves the camera view of the corresponding camera. The working principle of the step S1 is as follows: since in step S1 the driving assembly only drives the calibration plate 5 to move in the X-axis direction or the Y-axis direction, and the first image information comprises at least two images of the camera 1 moving in its camera view with respect to the calibration plate 5, i.e. the first image information comprises a plurality of images of different positions of the calibration plate 5 in the camera view, this embodiment can obtain the coordinates of the calibration plate 5 in the first image information by using the existing image positioning method, and if there is no deviation in the installation of the camera 1, the coordinates of the calibration plate 5 in these images will only change in one axial direction of the camera coordinate system (camera view); if there is a deviation in the installation of the camera 1, the coordinates of the calibration plate 5 in the images will change in two axial directions of the camera coordinate system, for example, the initial coordinates of the calibration plate 5 are (10, 5), the first image information corresponds to the two images, the driving assembly drives the calibration plate 5 to move down by 5 pixel distances along the X-axis direction, if there is no deviation in the installation of the camera 1, the coordinates of the calibration plate 5 in the two images are (10, 5) and (5, 5), respectively; if there is a deviation in the mounting of the camera 1, the coordinates of the calibration plate 5 in the two images are (10, 5) and (6, 4), respectively, so that the step S1 can calculate the mounting deflection angle information of the corresponding camera 1 from the first image information. It should be understood that, since the first image information includes at least two images corresponding to the movement of the camera 1 with respect to the calibration plate 5 in the camera view thereof, and the number of cameras 1 of this embodiment is plural, the number of pieces of the mounting deflection angle information calculated in step S1 is the same as the number of cameras 1, that is, each piece of the mounting deflection angle information corresponds to one camera 1. It should also be understood that if the moving distance of the calibration plate 5 in step S1 is too small, there will be a situation in which the corresponding camera 1 is misjudged to be free of mounting deviation due to the moving distance of the calibration plate 5 being too small, so in order to avoid a situation in which the camera 1 is misjudged to be free of mounting deviation due to the moving distance of the calibration plate 5 being too small, the moving distance of the calibration plate 5 in this embodiment is 3/4 or more of the diameter of the camera field of view, that is, the center position distance of the calibration plate having at least two images is 3/4 or more of the diameter of the camera field of view.
The preset interval in step S2 is a preset value, and the preset interval may be an interval between two cameras 1, when the distance that the driving component drives the calibration plate 5 to move is equal to the preset interval, the calibration plate 5 can move from the camera view of one camera 1 to the camera view of the other camera 1, and it should be understood that a person skilled in the art can preset the interval according to actual needs. The installation deviation information in step S2 is an offset amount between the two cameras 1, the offset amount being caused by an installation error of the two cameras 1, the offset amount including an X-axis direction offset amount and/or a Y-axis direction offset amount between the two cameras, and the installation deviation information being capable of reflecting whether there is a deviation between the two cameras 1 and whether there is a deviation between the camera coordinate systems corresponding to the two cameras 1. The working principle of the step S2 is as follows: because in step S2, the driving component drives the calibration plate 5 to move along the Y-axis direction only based on the preset spacing, the second image information includes the images of the corresponding cameras 1 moving along the preset spacing with respect to the calibration plate 5 and appearing in the camera view field thereof, and the cameras 1 are all cameras 1 of the same model and specification, i.e. the camera view field ranges of the cameras 1 are the same, if the installation deviation information is 0, the coordinates of the calibration plate 5 in the camera coordinate system will only change in the Y-axis direction; if the installation deviation information is not 0, the coordinates of the calibration plate 5 in the camera coordinate system will change in the X-axis direction and the Y-axis direction, for example, the coordinates of the calibration plate 5 in the camera coordinate system of the corresponding camera 1 before moving are (10, 5), if there is no deviation between the two cameras 1, the coordinates of the calibration plate 5 in the camera coordinate system of the corresponding camera 1 after moving may be (8, 5) or (9, 5); if there is a deviation in the installation of the camera 1, the coordinates of the calibration plate 5 in the camera coordinate system corresponding to the camera 1 after moving may be (8, 3) or (9, 6), and the installation deviation of the camera 1 itself may also generate installation deviation information, so that step S2 needs to calculate the installation deviation information between the plurality of cameras 1 according to the second image information, the installation deviation angle information and the preset distance.
Step S3 may convert the existing pose conversion algorithm or pose conversion model into a pose relationship between the plurality of cameras 1 based on the installation deflection angle information and the installation deviation information, so as to calibrate all the cameras 1. It should be understood that, step S3 may also determine, based on the installation deflection angle information and the installation deviation information, an angle between a connection line between the plurality of cameras 1 and the driving assembly, so as to calibrate the pose relationship between the cameras 1 and the substrate.
The working principle of the embodiment is as follows: according to the multi-camera calibration method provided by the application, the installation deflection angle information of the corresponding cameras 1 is calculated according to the first image information, the installation deflection angle information and the preset spacing are calculated according to the second image information, the installation deviation information between the plurality of cameras 1 is finally determined based on the installation deflection angle information and the installation deviation information, so that all the cameras 1 can be calibrated, and the calibration of the plurality of cameras 1 can be realized according to the first image information and the second image information, so that an auxiliary system or an auxiliary camera is not required to be arranged in the method, the problems of high calibration cost and complex and complicated calculation process of the multi-camera calibration method caused by the requirement of the auxiliary system or the auxiliary camera are effectively solved, and the method does not need to use a large calibration plate for multi-camera calibration, so that the geometric errors of the large calibration plate and the calibration deviations caused by the geometric errors are eliminated, the installation deviations of the single camera 1 are considered when the plurality of the cameras 1 are calibrated, and the problem of improving the precision of the base plate caused by the geometric errors and the calibration errors and the installation deviations of the single camera 1 are not considered is effectively solved.
In some embodiments, the calibration plate 5 is provided with a feature area 6, the first image information comprising two images corresponding to the movement of the camera 1 with respect to the calibration plate 5 within its camera field of view, step S1 comprising:
s11, controlling a driving assembly to drive the calibration plate 5 to move along the X-axis direction or the Y-axis direction, and acquiring first image information of each camera 1;
s12, respectively acquiring first position information and second position information according to the first image information, wherein the first position information is the position of the characteristic region 6 in the camera coordinate system of one image, and the second position information is the position of the characteristic region 6 in the camera coordinate system of the other image;
s13, calculating the installation deflection angle information of the corresponding camera 1 according to the first position information and the second position information.
The feature area 6 of this embodiment may be in the form of a circle, a cross, a square, etc., and the feature area 6 of this embodiment is preferably a cross. The working principle of this embodiment is similar to that of the above-described step S1 and will not be discussed in detail here. The first position information is preferably the position of the center of the feature region 6 in the camera coordinate system of one of the images, and the second position information is preferably the position of the center of the feature region 6 in the camera coordinate system of the other image.
In some embodiments, the calculation formula of step S13 is shown in formula (1):
（1）
where Δθ represents the mounting deflection angle information of the camera 1, (x) 1 ，y 1 ) Representing the first position information, (x) 2i ，y 2i ) Representing second location information.
In some embodiments, step S12 includes the steps of:
s121, repeatedly executing step S11 to acquire a plurality of first image information about each camera 1;
s122, acquiring a plurality of groups of first position information and second position information according to the plurality of first image information;
step S13 includes the steps of:
s131, calculating initial installation angle information according to the first position information and the corresponding second position information, and taking an average value of all the initial installation angle information as installation deflection angle information of the camera 1.
Specifically, the calculation formula of step S131 is shown in formula (2):
（2）
where n represents the number of times of repeating step S11, Δθ represents the mounting deflection angle information of the camera 1, Δθ i Represents initial installation angle information calculated based on the first position information and the second position information acquired at the time of the ith execution of step S11, (x) 1i ，y 1i ) Represents the first position information obtained when step S11 is performed the ith time, (x) 2i ，y 2i ) Representing the second position information acquired at the ith execution of step S11. The embodiment firstly acquires a plurality of first image information, respectively calculates the initial installation angle information corresponding to each first image information, and then takes the average value of the plurality of initial installation angle information as the installation deflection angle information of the camera 1, and the embodiment is equivalent to the verification of the installation deflection angle information, so the embodiment can effectively reduce the measurement error, thereby effectively reducing the measurement error And the measurement accuracy of the installation deflection angle information is improved.
In some embodiments, the calibration plate 5 is provided with a feature area 6, the installation deviation information includes X-direction deviation information and Y-direction deviation information, the preset distance is determined by measurement of a measuring tool, and step S2 includes the steps of:
s21, controlling the driving assembly to drive the calibration plate 5 to move along the Y axis based on the preset interval, so that the calibration plate 5 sequentially enters the camera fields of all the cameras 1, and acquiring second image information about each camera 1;
s22, acquiring third position information and quadrant information of the corresponding camera 1 based on each piece of second image information, wherein the third position information is the position of the feature region 6 in the camera coordinate system of the corresponding camera 1, and the quadrant information is the quadrant of the feature region 6 in the camera coordinate system of the corresponding camera 1;
s23, calculating X-axis deviation information of the characteristic region 6 in a corresponding camera coordinate system according to each third position information, and calculating X-direction deviation information among the cameras 1 according to the X-axis deviation information and the corresponding quadrant information;
s24, calculating Y-direction deviation information among the cameras 1 according to the third position information, the corresponding quadrant information and the preset distance.
The preset spacing of this embodiment is determined by measurement by a measuring tool, which may be a grating ruler or a laser interferometer, etc. The Y-axis deviation information in step S23 is the deviation of the center of the feature region 6 in the camera coordinate system from the camera optical center of the corresponding camera 1 in the Y-axis direction, and the Y-axis deviation information is preferably the deviation of the center of the feature region 6 in the camera coordinate system from the camera optical center of the corresponding camera 1 in the Y-axis direction. The third position information of this embodiment is preferably the position of the center of the feature area 6 in the camera coordinate system of the corresponding camera 1, and the quadrant information of this embodiment is preferably the quadrant of the center of the feature area 6 in the camera coordinate system of the corresponding camera 1. Since the difference in quadrants of the feature region 6 in the camera coordinate system of the corresponding camera 1 results in the difference in calculation formulas used when calculating the Y-direction deviation information and when calculating the X-direction deviation information, this embodiment selects the corresponding calculation formulas according to the quadrant information when calculating the Y-direction deviation information and the X-direction deviation information. Preferably, this embodiment performs calculation of Y-direction deviation information and X-direction deviation information one by one with other cameras 1 with the camera field of view of the first camera 1 as a reference.
In some embodiments, step S1 further comprises the step of performing after step S13:
s14, acquiring moving pixel distance information of the feature area 6 in the field of view of the camera according to the first image information and actual movement amount information of the calibration plate 5 based on the measuring tool, and calculating unit pixel information of the camera 1 according to the moving pixel distance information and the actual movement amount information;
the step of calculating the X-direction deviation information between the cameras 1 from the X-axis deviation information and the corresponding quadrant information includes:
calculating X-direction deviation information among the cameras 1 according to the X-axis deviation information, the corresponding quadrant information and the unit pixel information;
step S24 includes:
s241, calculating Y-direction deviation information between the cameras 1 according to the third position information, the corresponding quadrant information, the preset distance and the unit pixel information.
The moving pixel distance information in step S14 is the pixel distance of the feature area 6 moving in the camera view of the corresponding camera 1, and the actual moving amount information is the actual moving distance of the calibration plate 5 in the X-axis direction or the Y-axis direction (i.e., the actual moving distance of the feature area 6) measured by using a measuring tool, which may be a grating scale or a laser interferometer, or the like. Since the first image information is at least two images of the corresponding camera 1 moving in its camera view with respect to the calibration plate 5, the moving pixel distance information may be understood as a difference in coordinates of the feature area 6 in the camera coordinate system to which the first image information corresponds, preferably the moving pixel distance information is a difference in coordinates of the center of the feature area 6 in the camera coordinate system to which the first image information corresponds. Specifically, the calculation formula of step S14 is shown in formula (3):
（3）
Where S denotes unit pixel information, Δl denotes actual movement amount information, and Δd denotes movement pixel distance information. It should be understood that if step S11 is repeatedly performed, the calculation formula of step S14 is shown in formula (4):
（4）
where S represents unit pixel information, n represents the number of times step S11 is repeatedly performed, Δl i Representing the actual movement amount information Δd obtained from the measuring tool when step S11 is executed the ith time i Indicating the moving pixel distance information acquired at the ith execution of step S11.
In some embodiments, the driving assembly comprises a motion platform bottom shaft and a gantry beam motion shaft 3, the calibration plate 5 is detachably mounted on the motion platform bottom shaft, the motion platform bottom shaft is used for driving the calibration plate 5 to move along the X-axis direction, an L-shaped mounting frame 7 is arranged on the gantry beam motion shaft 3, the calibration plate 5 is detachably mounted at one end, far away from the gantry beam motion shaft 3, of the L-shaped mounting frame 7, and the gantry beam motion shaft 3 is used for driving the calibration plate 5 to move along the Y-axis direction. Specifically, the multi-camera calibration system of this embodiment further includes a workbench 4, the workbench 4 is connected with a bottom shaft of the moving platform, the calibration plate 5 is detachably mounted on the workbench 4, and the bottom shaft of the moving platform drives the calibration plate 5 to move in a manner of driving the workbench 4 to move. Since the gantry beam moving axis 3 is high and the working distance of the camera 1 is limited, the calibration plate 5 of this embodiment is mounted on the gantry beam moving axis 3 through the L-shaped mounting bracket 7 in order for the camera 1 to smoothly acquire the second image information. In this embodiment, the preset distance is equal to the actual movement amount of the gantry beam moving axis 3, and step S3 may determine an included angle between the connecting line between the plurality of cameras 1 and the gantry beam moving axis 3 based on the installation deflection angle information and the installation deviation information, so as to calibrate the pose relationship between the plurality of cameras 1 and the substrate. It should be understood that, in the embodiment, the motion platform bottom shaft and the gantry beam motion shaft 3 are equivalent to two independent driving mechanisms, and when the step S1 is executed, if the calibration plate 5 needs to be driven to move along the X-axis direction, the calibration plate is installed on the workbench 4, and the motion platform bottom shaft drives the calibration plate 5 to move along the X-axis direction by driving the workbench 4 to move along the X-axis direction; when the step S1 is executed, if the calibration plate 5 is required to be driven to move along the Y-axis direction, the calibration plate 5 is installed on the L-shaped installation frame 7, and the gantry beam moving shaft 3 drives the calibration plate 5 to move along the Y-axis direction in a mode of driving the L-shaped installation frame 7 to move along the Y-axis direction; when executing step S2, in this embodiment, the calibration plate 5 is mounted on the L-shaped mounting frame 7, and the gantry beam moving shaft 3 drives the calibration plate 5 to move along the Y-axis direction by driving the L-shaped mounting frame 7 to move along the Y-axis direction.
As shown in fig. 5, taking the example of calculating the mounting deviation information between the two cameras 1, the camera 1 located on the left side of fig. 5 is referred to as a first camera, the camera 1 located on the right side of fig. 5 is referred to as a second camera, the quadrant in which the feature region 6 is located in the camera coordinate system of the first camera is a second quadrant, and the quadrant in which the feature region 6 is located in the camera coordinate system of the second camera is a first quadrant. The calculation formula of step S23 is shown in formula (5):
（5）
wherein l 1 Representing the distance between the center of the feature region 6 in the camera coordinate system and the camera optical center of the first camera, (x) 3 ，y 3 ) Representing third position information corresponding to the first camera, (x) 01 ，y 01 ) Representing the coordinates of the camera optical center of the first camera in the camera coordinate system of the first camera, Δθ cam1 Representing the mounting deflection angle information (angle at a in fig. 5) of the first camera, Δθ cam1 Calculated from the formula (1) or the formula (2), θ cam1 An angle (angle at b in fig. 5) indicating an angle (d) of an included angle between a line connecting a center of the feature region 6 and a center of the first camera and a vertical direction (X-axis direction) when the feature region 6 is at the second image limit of the first camera 1 Representing X-axis deviation information corresponding to the first camera, l 2 Representing the center and second of the feature region 6 in the camera coordinate system Distance between camera optical centers of cameras, (x) 4 ，y 4 ) Representing third position information corresponding to the second camera, (x) 02 ，y 02 ) Representing the coordinates of the camera optical center of the second camera in the camera coordinate system of the second camera, Δθ cam2 Representing the mounting deflection angle information (angle at c in fig. 5) of the second camera, Δθ cam2 Calculated from the formula (1) or the formula (2), θ cam21 An angle (angle at d in fig. 5) representing an angle between a line connecting the center of the feature region 6 with the center of the second camera and a perpendicular line connecting the center of the feature region 6 with the x-axis of the camera coordinate system of the second camera when the feature region 6 is at the first quadrant of the second camera, d 2 Representing X-axis deviation information corresponding to the second camera, d x The X-direction deviation information between the first camera and the second camera is represented, and S represents unit pixel information.
The calculation formula of step S241 is shown in formula (6):
（6）
wherein d y Represents Y-direction deviation information, L represents a preset pitch determined by measurement by a measuring tool, S represents unit pixel information, L 1 Representing the distance θ between the center of the feature region 6 in the camera coordinate system and the camera optical center of the first camera cam1 An angle l representing an angle between a line connecting the center of the feature region 6 and the center of the first camera and the vertical direction, when the feature region 6 is at the second image limit of the first camera 2 Representing the distance θ between the center of the feature region 6 in the camera coordinate system and the camera optical center of the second camera cam21 An angle Δθ representing an angle between a line connecting a center of the feature region 6 with a center of the second camera and a perpendicular line connecting the center of the feature region 6 with an x-axis of a camera coordinate system of the second camera when the feature region 6 is at the first quadrant of the second camera cam2 Indicating the mounting deflection angle information of the second camera, delta theta cam2 Calculated from formula (1) or formula (2), l of this example 1 、l 2 、θ cam1 And theta cam21 Are calculated by the formula (5).
Step S3, calculating a calculation formula of an included angle between a connecting line of the first camera and the second camera and the gantry beam motion axis 3 is shown as formula (7):
; （7）/>
wherein alpha represents an included angle between a connecting line of the first camera and the second camera and a gantry beam moving axis 3, and d 1 Representing X-axis deviation information corresponding to the first camera, d 2 Representing X-axis deviation information corresponding to the second camera, d y Representing Y-direction deviation information, d of this embodiment 1 And d 2 Calculated from formula (5), d of this example y Calculated from equation (6).
As shown in fig. 6, taking the example of calculating the mounting deviation information between the two cameras 1, the camera 1 located on the left side of fig. 6 is referred to as a first camera, the camera 1 located on the right side of fig. 6 is referred to as a second camera, the quadrant in which the feature region 6 is located in the camera coordinate system of the first camera is a second quadrant, and the quadrant in which the feature region 6 is located in the camera coordinate system of the second camera is a second quadrant. The calculation formula of step S23 is shown in formula (8):
（8）
Wherein l 1 Representing the distance between the center of the feature region 6 in the camera coordinate system and the camera optical center of the first camera, (x) 3 ，y 3 ) Representing third position information corresponding to the first camera, (x) 01 ，y 01 ) Representing the coordinates of the camera optical center of the first camera in the camera coordinate system of the first camera, Δθ cam1 Representing the mounting deflection angle information (angle at a in fig. 6) of the first camera, Δθ cam1 Calculated from the formula (1) or the formula (2), θ cam1 Indicating that the characteristic region 6 is at the second image of the first camera, the center of the characteristic region 6 is aligned with the firstThe angle (angle at b in fig. 6) between the line connecting the centers of the cameras and the vertical direction (X-axis direction), d 1 Representing X-axis deviation information corresponding to the first camera, l 2 Representing the distance between the center of the feature region 6 in the camera coordinate system and the camera optical center of the second camera, (x) 4 ，y 4 ) Representing third position information corresponding to the second camera, (x) 02 ，y 02 ) Representing the coordinates of the camera optical center of the second camera in the camera coordinate system of the second camera, Δθ cam2 Representing the mounting deflection angle information (angle at c in fig. 6) of the second camera, Δθ cam2 Calculated from the formula (1) or the formula (2), θ cam22 An angle (angle at d in fig. 6) indicating an angle between a line connecting the center of the feature region 6 and the center of the second camera and a vertical direction (X-axis direction) d, when the feature region 6 is at the second image limit of the second camera 2 Representing X-axis deviation information corresponding to the second camera, d x The X-direction deviation information between the first camera and the second camera is represented, and S represents unit pixel information.
The calculation formula of step S241 is shown in formula (9):
（9）
wherein d y Represents Y-direction deviation information, L represents a preset pitch determined by measurement by a measuring tool, S represents unit pixel information, L 1 Representing the distance θ between the center of the feature region 6 in the camera coordinate system and the camera optical center of the first camera cam1 An angle l representing an angle between a line connecting the center of the feature region 6 and the center of the first camera and the vertical direction, when the feature region 6 is at the second image limit of the first camera 2 Representing the distance θ between the center of the feature region 6 in the camera coordinate system and the camera optical center of the second camera cam22 An angle representing an angle of an included angle between a line connecting a center of the feature region 6 and a center of the second camera and a vertical direction when the feature region 6 is at the second image limit of the first camera, i of this embodiment 1 、l 2 、θ cam1 And theta cam22 Are calculated by the formula (8).
Step S3, calculating a calculation formula of an included angle between a connecting line of the first camera and the second camera and the gantry beam motion axis 3 is shown as (10):
（10）
wherein alpha represents an included angle between a connecting line of the first camera and the second camera and a gantry beam moving axis 3, and d 1 Representing X-axis deviation information corresponding to the first camera, d 2 Representing X-axis deviation information corresponding to the second camera, d y Representing Y-direction deviation information, d of this embodiment 1 And d 2 Calculated from formula (8), d of this example y Calculated from formula (9).
As shown in fig. 7, taking the example of calculating the mounting deviation information between the two cameras 1, the camera 1 located on the left side of fig. 7 is referred to as a first camera, the camera 1 located on the right side of fig. 7 is referred to as a second camera, the quadrant in which the feature region 6 is located in the camera coordinate system of the first camera is a second quadrant, and the quadrant in which the feature region 6 is located in the camera coordinate system of the second camera is a third quadrant. The calculation formula of step S23 is shown in formula (11):
（11）
wherein l 1 Representing the distance between the center of the feature region 6 in the camera coordinate system and the camera optical center of the first camera, (x) 3 ，y 3 ) Representing third position information corresponding to the first camera, (x) 01 ，y 01 ) Representing the coordinates of the camera optical center of the first camera in the camera coordinate system of the first camera, Δθ cam1 Representing the mounting deflection angle information (angle at a in fig. 7) of the first camera, Δθ cam1 Calculated from the formula (1) or the formula (2), θ cam1 Indicating that the characteristic region 6 is at the second image of the first camera, the center of the characteristic region 6 is aligned with the first phase An angle (angle at b in fig. 7) of an angle between a line connecting centers of the machine and a vertical direction (X-axis direction), d 1 Representing X-axis deviation information corresponding to the first camera, l 2 Representing the distance between the center of the feature region 6 in the camera coordinate system and the camera optical center of the second camera, (x) 4 ，y 4 ) Representing third position information corresponding to the second camera, (x) 02 ，y 02 ) Representing the coordinates of the camera optical center of the second camera in the camera coordinate system of the second camera, Δθ cam2 Representing the mounting deflection angle information (angle at c in fig. 7) of the second camera, Δθ cam2 Calculated from the formula (1) or the formula (2), θ cam23 An angle (angle at d in fig. 7) representing an angle between a line connecting the center of the feature region 6 and the center of the second camera and a perpendicular line connecting the center of the feature region 6 and the x-axis of the camera coordinate system of the second camera when the feature region 6 is at the third image point of the second camera, d 2 Representing X-axis deviation information corresponding to the second camera, d x The X-direction deviation information between the first camera and the second camera is represented, and S represents unit pixel information.
The calculation formula of step S241 is shown in formula (12):
（12）
wherein d y Represents Y-direction deviation information, L represents a preset pitch determined by measurement by a measuring tool, S represents unit pixel information, L 1 Representing the distance θ between the center of the feature region 6 in the camera coordinate system and the camera optical center of the first camera cam1 An angle l representing an angle between a line connecting the center of the feature region 6 and the center of the first camera and the vertical direction, when the feature region 6 is at the second image limit of the first camera 2 Representing the distance θ between the center of the feature region 6 in the camera coordinate system and the camera optical center of the second camera cam23 Representing that the characteristic region 6 is at the third quadrant of the second camera, the line connecting the center of the characteristic region 6 with the center of the second camera and the phase of the center of the characteristic region 6 with the second cameraAngle of included angle between perpendicular lines of x-axis of machine coordinate system, i of this embodiment 1 、l 2 、θ cam1 And theta cam23 Are calculated by the formula (11).
Step S3, calculating a calculation formula of an included angle between a connecting line of the first camera and the second camera and the gantry beam motion axis 3 is shown as formula (13):
（13）
wherein alpha represents an included angle between a connecting line of the first camera and the second camera and a gantry beam moving axis 3, and d 1 Representing X-axis deviation information corresponding to the first camera, d 2 Representing X-axis deviation information corresponding to the second camera, d y Representing Y-direction deviation information, d of this embodiment 1 And d 2 Calculated from formula (11), d of this example y Calculated from equation (12).
As shown in fig. 8, taking the example of calculating the mounting deviation information between the two cameras 1, the camera 1 located on the left side of fig. 8 is referred to as a first camera, the camera 1 located on the right side of fig. 8 is referred to as a second camera, the quadrant in which the feature region 6 is located in the camera coordinate system of the first camera is a second quadrant, and the quadrant in which the feature region 6 is located in the camera coordinate system of the second camera is a fourth quadrant. The calculation formula of step S23 is shown in formula (14):
（14）
wherein l 1 Representing the distance between the center of the feature region 6 in the camera coordinate system and the camera optical center of the first camera, (x) 3 ，y 3 ) Representing third position information corresponding to the first camera, (x) 01 ，y 01 ) Representing the coordinates of the camera optical center of the first camera in the camera coordinate system of the first camera, Δθ cam1 Representing the mounting deflection angle information (angle at a in fig. 8) of the first camera, Δθ cam1 Calculated from the formula (1) or the formula (2)，θ cam1 An angle (angle at b in fig. 8) indicating an angle (d) of an included angle between a line connecting a center of the feature region 6 and a center of the first camera and a vertical direction (X-axis direction) when the feature region 6 is at the second image limit of the first camera 1 Representing X-axis deviation information corresponding to the first camera, l 2 Representing the distance between the center of the feature region 6 in the camera coordinate system and the camera optical center of the second camera, (x) 4 ，y 4 ) Representing third position information corresponding to the second camera, (x) 02 ，y 02 ) Representing the coordinates of the camera optical center of the second camera in the camera coordinate system of the second camera, Δθ cam2 Representing the mounting deflection angle information (angle at c in fig. 8) of the second camera, Δθ cam2 Calculated from the formula (1) or the formula (2), θ cam24 An angle (angle at d in fig. 8) indicating an angle between a line connecting the center of the feature region 6 and the center of the second camera and a vertical direction (X-axis direction) d, when the feature region 6 is at the fourth image limit of the second camera 2 Representing X-axis deviation information corresponding to the second camera, d x The X-direction deviation information between the first camera and the second camera is represented, and S represents unit pixel information.
The calculation formula of step S241 is shown in formula (15):
（15）
wherein d y Represents Y-direction deviation information, L represents a preset pitch determined by measurement by a measuring tool, S represents unit pixel information, L 1 Representing the distance θ between the center of the feature region 6 in the camera coordinate system and the camera optical center of the first camera cam1 An angle l representing an angle between a line connecting the center of the feature region 6 and the center of the first camera and the vertical direction, when the feature region 6 is at the second image limit of the first camera 2 Representing the distance θ between the center of the feature region 6 in the camera coordinate system and the camera optical center of the second camera cam24 Indicating that the characteristic region 6 is at the fourth quadrant of the second camera, the center of the characteristic region 6 is aligned with the second cameraIs connected with the vertical of the center of the line the angle of the included angle between the directions, l of this example 1 、l 2 、θ cam1 And theta cam24 Are calculated by equation (14).
Step S3, calculating a calculation formula of an included angle between a connecting line of the first camera and the second camera and the gantry beam motion axis 3 is shown as formula (16):
（16）
wherein alpha represents an included angle between a connecting line of the first camera and the second camera and a gantry beam moving axis 3, and d 1 Representing X-axis deviation information corresponding to the first camera, d 2 Representing X-axis deviation information corresponding to the second camera, d y Representing Y-direction deviation information, d of this embodiment 1 And d 2 Calculated from formula (14), d of this example y Calculated from equation (15).
It should be appreciated that if the center of the feature area coincides with the center of the camera coordinate system, the present application may use any of the above calculations to calculate Y-direction deviation information and X-direction deviation information. It should be further understood that the calibration plate 5 may be disposed to extend along the Y-axis direction, and the calibration plate 5 may also be configured to adjust its mounting angle according to the mounting deflection angle information of the camera 1, and the present application only shows a schematic diagram for adjusting the mounting angle of the calibration plate 5 according to the mounting deflection angle information of the camera 1.
It should be understood that the above embodiment only shows the case where the feature region 6 is located in the second quadrant of the first camera and in the four quadrants of the second camera, if the feature region 6 is located in the other three quadrants of the first camera, the X-axis deviation information of the second camera, the X-axis deviation information between the first camera and the second camera, and then the Y-axis deviation information is calculated according to the third position information, the corresponding quadrant information, the preset pitch, and the unit pixel information may be calculated using any one or more of the equation (5), the equation (8), the equation (11), and the equation (14).
In some embodiments, between step S2 and step S3 further comprises the steps of:
s4, repeatedly executing the step S1 and the step S2 to obtain a plurality of first deviation information groups and a plurality of second deviation information groups, and determining target installation deflection angle information and target installation deviation information according to the first deviation information groups and the corresponding second deviation information groups, wherein the first deviation information groups comprise installation deflection angle information and installation deviation information calculated based on data measured by a grating ruler, and the second deviation information groups comprise installation deflection angle information and installation deviation information calculated based on data measured by a laser interferometer;
The step S3 comprises the following steps:
s31, determining pose relations among the cameras 1 based on the target installation deflection angle information and the target installation deviation information so as to calibrate all the cameras 1.
Step S4, determining target installation deflection angle information and target installation deflection information according to the first deflection information group and the corresponding second deflection information group, wherein the specific flow is as follows: the deviation of the first deviation information group and the corresponding second deviation information group is calculated respectively to obtain a plurality of deviation information, specifically, the deviation information is the sum of the difference value of the installation deflection angle information corresponding to the first deviation information group and the installation deflection angle information corresponding to the second deviation information group and the difference value of the installation deflection information corresponding to the first deviation information group and the installation deflection information corresponding to the second deviation information group, then the installation deflection angle information corresponding to the first deviation information group or the installation deflection angle information corresponding to the minimum value of the deviation information is used as target installation deflection angle information, and the installation deflection information corresponding to the first deviation information group or the second deviation information group corresponding to the minimum value of the deviation information is used as target installation deflection information.
As can be seen from the above, according to the multi-camera calibration method provided by the application, the installation deflection angle information of the corresponding camera 1 is calculated according to the first image information, the installation deflection angle information and the preset distance are calculated according to the second image information, the installation deviation information between the plurality of cameras 1 is calculated according to the installation deflection angle information and the installation deviation information, and finally the pose relation between the plurality of cameras 1 is determined based on the installation deflection angle information and the installation deviation information, so as to calibrate all the cameras 1.
In a second aspect, the present application also provides a high precision apparatus comprising a multi-camera calibration system for performing the multi-camera calibration method as provided in the first aspect above.
The embodiment of the application also provides a high-precision equipment, which comprises a multi-camera calibration system, wherein the multi-camera calibration system is used for executing the multi-camera calibration method provided in the first aspect. The working principle of the high-precision equipment provided by the embodiment of the application is the same as that of the multi-camera calibration method provided by the first aspect, and the working principle is not discussed in detail here.
According to the high-precision equipment provided by the application, the installation deflection angle information of the corresponding cameras 1 is calculated according to the first image information, the installation deflection angle information and the preset distance are calculated according to the second image information, the installation deviation information between the plurality of cameras 1 is finally determined based on the installation deflection angle information and the installation deviation information, so that all the cameras 1 are calibrated, and the equipment can realize the calibration of the plurality of cameras 1 only according to the first image information and the second image information, so that an auxiliary system or an auxiliary camera is not required to be arranged, the problems that the calibration cost of the multi-camera calibration equipment is high and the calculation process is complex and complicated due to the need of the auxiliary system or the auxiliary camera are solved effectively, and the equipment does not need to use a large calibration plate for multi-camera calibration, so that the geometric errors of the large calibration plate and the calibration deviations caused by the geometric errors are eliminated, and the installation deviations of the single camera 1 are considered when the plurality of cameras 1 are calibrated, the equipment effectively solves the problem that the calibration precision of the base plate is improved due to the geometric errors and the installation deviations of the single camera 1 are not considered.
In a third aspect, the present application provides a computer readable storage medium having stored thereon a computer program which, when executed by a processor, performs a method in any of the alternative implementations of the above embodiments to implement the following functions: s1, controlling a driving assembly to drive a calibration plate 5 to move along the X-axis direction or the Y-axis direction, acquiring first image information of each camera 1, and calculating installation deflection angle information of the corresponding camera 1 according to the first image information, wherein the first image information comprises at least two images of the corresponding camera 1 moving in a camera view of the calibration plate 5; s2, controlling the driving assembly to drive the calibration plate 5 to move along the Y axis based on the preset interval so that the calibration plate 5 sequentially enters the camera vision fields of all the cameras 1, acquiring second image information of each camera 1, and calculating installation deviation information among the plurality of cameras 1 according to the second image information, the installation deflection angle information and the preset interval, wherein the second image information comprises images which appear in the camera vision fields of the corresponding cameras 1 when the calibration plate 5 moves according to the preset interval; and S3, determining pose relations among the cameras 1 based on the installation deflection angle information and the installation deviation information so as to calibrate all the cameras 1.
As can be seen from the above, the multi-camera calibration method, the high-precision equipment and the computer readable storage medium provided by the application are characterized in that the installation deflection angle information of the corresponding camera 1 is calculated according to the first image information, the installation deflection angle information and the preset distance are calculated according to the second image information, the installation deviation information between the plurality of cameras 1 is calculated according to the installation deflection angle information and the installation deviation information, and finally the pose relation between the plurality of cameras 1 is determined based on the installation deflection angle information and the installation deviation information, so as to calibrate all the cameras 1, and the method can realize the calibration of the plurality of cameras 1 according to the first image information and the second image information, so that an auxiliary system or an auxiliary camera is not required to be arranged in the method, thereby effectively solving the problems of high calibration cost and complicated calculation process of the multi-camera calibration method caused by the need of the auxiliary system or the auxiliary camera, and the method can eliminate the geometric error of the large calibration plate and the calibration deviation caused by the geometric error, and the method considers the installation deviation of the single camera 1 when the plurality of cameras 1 are calibrated, thereby effectively solving the problems of the geometric error and the calibration error caused by the fact that the single-camera calibration error and the calibration error is not considered, and the calibration precision is not poor.
In this document, relational terms such as first and second, and the like may be 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.
The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and variations will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (10)

1. The multi-camera calibration method is characterized by being applied to a multi-camera calibration system, wherein the multi-camera calibration system comprises a calibration plate, a driving assembly and a plurality of cameras, the cameras are installed along the Y-axis direction, the camera fields of vision of the cameras are not overlapped with each other, the calibration plate is connected with the driving assembly, the driving assembly is used for driving the calibration plate to move along the X-axis direction or the Y-axis direction, and the multi-camera calibration method comprises the following steps:
s1, controlling the driving assembly to drive the calibration plate to move along the X-axis direction or the Y-axis direction, acquiring first image information of each camera, and calculating installation deflection angle information of a corresponding camera according to the first image information, wherein the first image information comprises at least two images of the corresponding camera moving in a camera view of the calibration plate;
S2, controlling the driving assembly to drive the calibration plate to move along the Y axis based on a preset interval, so that the calibration plate sequentially enters the camera fields of all cameras, acquiring second image information of each camera, and calculating installation deviation information among a plurality of cameras according to the second image information, the installation deflection angle information and the preset interval, wherein the second image information comprises images of the corresponding cameras in the camera fields of the calibration plate according to the preset interval, and the installation deviation information is the offset between the two cameras;
and S3, determining pose relations among the cameras based on the installation deflection angle information and the installation deviation information so as to calibrate all the cameras.
2. The method for calibrating a multi-camera according to claim 1, wherein the calibration plate is provided with a feature area, and step S1 comprises:
s11, controlling the driving assembly to drive the calibration plate to move along the X-axis direction or the Y-axis direction, and acquiring first image information of each camera;
s12, respectively acquiring first position information and second position information according to the first image information, wherein the first position information is the position of the characteristic region in a camera coordinate system of one image, and the second position information is the position of the characteristic region in a camera coordinate system of the other image;
S13, calculating installation deflection angle information corresponding to the camera according to the first position information and the second position information.
3. The multi-camera calibration method according to claim 2, characterized in that step S12 includes the steps of:
s121, repeatedly executing step S11 to acquire a plurality of first image information about each camera;
s122, acquiring a plurality of groups of first position information and second position information according to a plurality of pieces of first image information;
step S13 includes the steps of:
s131, calculating initial installation angle information according to the first position information and the corresponding second position information, and taking the average value of all the initial installation angle information as installation deflection angle information of the camera.
4. The multi-camera calibration method according to claim 2, wherein the calculation formula of step S13 is as follows:
;
wherein Δθ represents the mounting deflection angle information, (x) 1 ，y 1 ) Representing the first position information, (x) 2 ，y 2 ) Representing second location information.
5. The multi-camera calibration method according to claim 2, wherein the installation deviation information includes X-direction deviation information and Y-direction deviation information, the preset spacing being determined by measurement by a measuring tool, step S2 comprising the steps of:
S21, controlling the driving assembly to drive the calibration plate to move along the Y axis based on a preset interval so that the calibration plate sequentially enters the camera fields of view of a plurality of cameras, and acquiring second image information about each camera;
s22, acquiring third position information and quadrant information of a corresponding camera based on each piece of second image information, wherein the third position information is the position of the characteristic region in a camera coordinate system of the corresponding camera, and the quadrant information is a quadrant of the characteristic region in the camera coordinate system of the corresponding camera;
s23, calculating X-axis deviation information of the characteristic region in a corresponding camera coordinate system according to the third position information, and calculating X-direction deviation information among cameras according to the X-axis deviation information and the corresponding quadrant information;
s24, calculating Y-direction deviation information among the cameras according to the third position information, the corresponding quadrant information and the preset distance.
6. The multi-camera calibration method according to claim 5, wherein step S1 further comprises the step of, after step S13:
s14, acquiring moving pixel distance information of the characteristic region in the camera view according to the first image information and actual moving amount information of the calibration plate based on the measuring tool, and calculating unit pixel information of a camera according to the moving pixel distance information and the actual moving amount information;
The step of calculating the X-direction deviation information between the cameras according to the X-axis deviation information and the corresponding quadrant information comprises the following steps:
calculating X-direction deviation information among cameras according to the X-axis deviation information, the corresponding quadrant information and the unit pixel information;
step S24 includes:
s241, calculating Y-direction deviation information among the cameras according to the third position information, the corresponding quadrant information, the preset distance and the unit pixel information.
7. The multi-camera calibration method according to claim 1, further comprising the steps between step S2 and step S3:
s4, repeatedly executing the step S1 and the step S2 to obtain a plurality of first deviation information groups and a plurality of second deviation information groups, and determining target installation deflection angle information and target installation deviation information according to the first deviation information groups and the corresponding second deviation information groups, wherein the first deviation information groups comprise installation deflection angle information and installation deviation information calculated based on data measured by a grating ruler, and the second deviation information groups comprise installation deflection angle information and installation deviation information calculated based on data measured by a laser interferometer;
The step S3 includes:
s31, determining pose relations among a plurality of cameras based on the target installation deflection angle information and the target installation deviation information so as to calibrate all the cameras.
8. The multi-camera calibration method according to claim 1, wherein the driving assembly comprises a moving platform bottom shaft and a gantry beam moving shaft, the calibration plate is detachably mounted on the moving platform bottom shaft, the moving platform bottom shaft is used for driving the calibration plate to move along the X-axis direction, an L-shaped mounting frame is arranged on the gantry beam moving shaft, the calibration plate is detachably mounted at one end, far away from the gantry beam moving shaft, of the L-shaped mounting frame, and the gantry beam moving shaft is used for driving the calibration plate to move along the Y-axis direction.
9. High precision equipment, characterized in that it comprises a multi-camera calibration system for performing the multi-camera calibration method according to any of claims 1-8.
10. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, performs the steps of the method according to any of claims 1-8.
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