CN113077522B - Automatic calibration device, automatic calibration method, electronic device, and readable storage medium - Google Patents
Automatic calibration device, automatic calibration method, electronic device, and readable storage medium Download PDFInfo
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Abstract
The invention provides an automatic calibration device, an automatic calibration method, electronic equipment and a readable storage medium, relates to the technical field of computer vision, is used for automatically calibrating a camera at a fixed installation position, and comprises the following steps: the device comprises an electric slide rail, a measuring instrument panel and a calibration plate; the calibration plate is arranged on the electric slide rail and can move along the electric slide rail, and a checkerboard coordinate system is arranged on the calibration plate; the measuring instrument panel is horizontally suspended and fixed on the electric sliding rail and is used for installing a measuring instrument for measuring the horizontal state and the azimuth angle of the calibration plate and the actual spatial position of the boundary point of the preset checkerboard in the checkerboard coordinate system. The method and the device solve the problems that monocular camera calibration in the prior art is not suitable for a scene with a fixed camera, full automation of calibration cannot be realized, and calibration efficiency and precision are low.
Description
Technical Field
The embodiment of the invention relates to the technical field of computer vision, in particular to an automatic calibration device, an automatic calibration method, electronic equipment and a readable storage medium.
Background
The methods for realizing camera calibration in the prior art are mainly divided into two types: firstly, a common Zhangyingyou calibration algorithm is adopted to calibrate the camera, and the internal parameter, the polynomial distortion parameter and the external parameter rotation and translation coefficients of the camera can be effectively calculated by acquiring a plurality of images. According to the scheme, a plurality of images need to be acquired, so that a large amount of manual participation is needed during acquisition, the labor cost is greatly increased due to more operation steps, and the efficiency is low. And secondly, realizing distortion correction by using a plane grid model. And the solution of the ideal points in the plane mesh model is obtained by means of central part diffusion, so that the precision is not guaranteed.
Therefore, the existing monocular camera calibration technology is not suitable for a scene with a fixed camera, can not realize full automation of calibration, and has lower calibration efficiency and precision.
Disclosure of Invention
The invention provides an automatic calibration device, an automatic calibration method, electronic equipment and a readable storage medium, and aims to solve the problems that monocular camera calibration in the prior art is not suitable for a camera-fixed scene, full automation of calibration cannot be realized, and the calibration efficiency and precision are low.
In order to solve the technical problem, the invention is realized as follows:
in a first aspect, the present invention provides an automatic calibration apparatus for automatically calibrating a camera at a fixed installation position, including: the device comprises an electric slide rail, a measuring instrument panel and a calibration plate; the calibration plate is arranged on the electric slide rail and can move along the electric slide rail, and a checkerboard coordinate system is arranged on the calibration plate;
the measuring instrument panel is horizontally suspended and fixed on the electric sliding rail and is used for installing a measuring instrument for measuring the horizontal state and the azimuth angle of the calibration plate and the actual spatial position of the boundary point of the preset checkerboard in the checkerboard coordinate system.
Optionally, the method further includes:
one end of the first ranging rod is connected with the first end of the electric slide rail, one end of the second ranging rod is connected with the second end of the electric slide rail, and the other end of the first ranging rod is connected with the other end of the second ranging rod;
the connecting end of the first ranging rod and the second ranging rod is arranged right below the camera and used for adjusting the horizontal distance between the camera and the calibration plate;
the first distance measuring ruler, the second distance measuring ruler and the electric slide rail form an isosceles triangle.
Optionally, the first ranging rod and the second ranging rod both include: an inner ruler and an outer ruler;
the inner ruler is nested in the outer ruler and used for stretching the inner ruler from the outer ruler to prolong the length of the first ranging ruler or the second ranging ruler.
Optionally, the method further includes: 3 electric lifting columns are respectively arranged at the bottom of the connecting end of the first ranging rod and the bottom of the connecting end of the second ranging rod and at the bottom of the two ends of the electric sliding rail and used for adjusting the horizontal state of the calibration plate.
Optionally, the measuring instrument includes at least one of:
the level gauge is arranged on the measuring instrument panel and used for measuring the horizontal state of the calibration plate;
the azimuth instrument is arranged on the measuring instrument panel and used for measuring the azimuth angle of the calibration plate;
and the real-time dynamic difference device is arranged on the measurement instrument panel and is used for measuring the actual spatial position of the boundary point of the preset checkerboard in the checkerboard coordinate system.
In a second aspect, the present invention provides an automatic calibration method, applied to the automatic calibration apparatus according to any one of the first aspect, the method including:
adjusting the calibration plate to be vertical to the horizontal plane according to the horizontal state of the calibration plate measured by a measuring instrument;
controlling the calibration plate to slide on the electric slide rail at a constant speed, and controlling a camera to shoot the calibration plate to obtain a plurality of shot images; the shot image comprises a first image when the boundary point of the preset checkerboard passes through the fixed position of the measuring instrument panel;
calculating calibration parameters of the camera according to the checkerboard coordinate system and the plurality of shot images;
converting a camera coordinate system of the camera into a world coordinate system according to the first image, the azimuth angle measured by the measuring instrument and the actual spatial position of the boundary point of the preset checkerboard;
and calculating the actual space position of any point under the camera coordinate system under the world coordinate system according to the calibration parameters of the camera.
Optionally, the automatic calibration apparatus further includes:
one end of the first ranging rod is connected with the first end of the electric slide rail, one end of the second ranging rod is connected with the second end of the electric slide rail, and the other end of the first ranging rod is connected with the other end of the second ranging rod; the connecting end of the first ranging rod and the second ranging rod is arranged right below the camera and used for adjusting the horizontal distance between the camera and the calibration plate; the first distance measuring ruler, the second distance measuring ruler and the electric slide rail form an isosceles triangle;
the 3 electric lifting columns are respectively arranged at the bottoms of the connecting ends of the first ranging ruler and the second ranging ruler and at the bottoms of the two ends of the electric sliding rail and are used for adjusting the horizontal state of the calibration plate;
the adjusting the calibration plate to be perpendicular to the horizontal plane according to the horizontal state of the calibration plate measured by the measuring instrument comprises:
mounting a level gauge on the measuring instrument panel, and measuring the horizontal state of the calibration plate;
and automatically adjusting the electric lifting column to enable the calibration plate to be vertical to the horizontal plane according to the horizontal state of the calibration plate.
Optionally, control the calibration board is in the last at the uniform velocity of electronic slide rail slides to control the camera to right the calibration board is shot, obtains many images of shooing, includes:
controlling the calibration plate to reciprocate on the electric slide rail for multiple times at a constant speed, and controlling a camera to shoot a motion video of the calibration plate;
and extracting a plurality of frame images from the motion video to be used as the shot images.
Optionally, the measuring instrument panel is horizontally suspended and fixed at the midpoint of the electric sliding rail;
the first image is an image when the boundary point of the preset checkerboard passes through the midpoint position of the electric slide rail.
Optionally, after calculating the calibration parameters of the camera according to the checkerboard coordinate system and the plurality of shot images, the method further includes:
calculating a back projection error based on the calibration parameters;
adjusting the calibration position of the shot image according to the back projection error;
and outputting the calibrated shot image for manual verification.
Optionally, the calibration parameter includes at least one of: the camera comprises internal parameters, distortion coefficients, a rotation matrix and translation vectors.
In a third aspect, the present invention provides an electronic device, comprising a memory, a processor, and a program stored on the memory and executable on the processor; the processor, when executing the program, implements the steps in the automatic calibration method according to any one of the second aspect.
In a fourth aspect, the present invention provides a readable storage medium, on which a program is stored, which when executed by a processor implements the steps in the automatic calibration method according to any one of the second aspect.
The automatic calibration device for the camera with the fixed installation position comprises an electric sliding rail, a measuring instrument panel and a calibration plate, wherein the distances from two ends of the electric sliding rail to the position right below the camera are equal, the calibration plate is installed on the electric sliding rail and can move along the electric sliding rail, and a checkerboard coordinate system is arranged on the calibration plate; the measuring instrument panel is horizontally suspended and fixed on the electric sliding rail and is used for installing a measuring instrument for measuring the horizontal state and the azimuth angle of the calibration plate and the actual spatial position of the boundary point of the preset checkerboard in the checkerboard coordinate system. The automatic calibration device can calculate calibration parameters of the camera by shooting images of a plurality of calibration plates on the electric sliding rail, convert a camera coordinate system into a world coordinate system by shooting the boundary points of a preset checkerboard on the calibration plates through images of a measuring instrument panel and the actual spatial positions of the boundary points of the preset checkerboard, and obtain any point on the images shot by the camera to obtain the actual spatial position of the point. The automatic calibration device is suitable for calibrating the camera at a fixed position under the environment complex working condition, and has strong adjustability.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
fig. 1 is a schematic structural diagram of an automatic calibration device according to an embodiment of the present invention;
fig. 2 is a second schematic structural diagram of an automatic calibration device according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a checkerboard coordinate system of an automatic calibration apparatus according to an embodiment of the present invention;
fig. 4 is a schematic flow chart of an automatic calibration method according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of an automatic calibration device according to an embodiment of the present invention; the embodiment of the present invention provides an automatic calibration apparatus, which is used for automatically calibrating a camera 100 at a fixed installation position, and includes: the device comprises an electric slide rail 11, a measuring instrument dial 12 and a calibration plate 13; the calibration plate 13 is mounted on the electric slide rail 11 and can move along the electric slide rail 11, and a checkerboard coordinate system is arranged on the calibration plate 13;
the measuring instrument dial 12 is horizontally suspended and fixed on the electric slide rail 11, and is used for installing a measuring instrument for measuring the horizontal state and the azimuth angle of the calibration plate 13 and the actual spatial position of the boundary point of the preset checkerboard in the checkerboard coordinate system.
In the embodiment of the present invention, the automatic calibration device is installed such that the distances from the two ends of the electric slide rail 11 to the position right below the camera 100 are equal.
In the embodiment of the invention, the automatic calibration device for the camera with the fixed installation position comprises an electric sliding rail, a measuring instrument panel and a calibration plate, wherein the distances from two ends of the electric sliding rail to the position right below the camera are equal, the calibration plate is installed on the electric sliding rail and can move along the electric sliding rail, and a checkerboard coordinate system is arranged on the calibration plate; the measuring instrument panel is horizontally suspended and fixed on the electric sliding rail and is used for installing a measuring instrument for measuring the horizontal state and the azimuth angle of the calibration plate and the actual spatial position of the boundary point of the preset checkerboard in the checkerboard coordinate system. The automatic calibration device can calculate calibration parameters of the camera by shooting images of a plurality of calibration plates on the electric sliding rail, convert a camera coordinate system into a world coordinate system by shooting the boundary points of a preset checkerboard on the calibration plates through images of a measuring instrument panel and the actual spatial positions of the boundary points of the preset checkerboard, and obtain any point on the images shot by the camera to obtain the actual spatial position of the point. The automatic calibration device is suitable for calibrating the camera at a fixed position under the environment complex working condition, and has strong adjustability.
Referring to fig. 1, the camera 100 of fig. 1 is fixed to a fixed point on a wall, the automatic calibration device is disposed on the ground at one side of the camera, and distances from two ends of the electric rail of the automatic calibration device to a position right below the camera are equal. Referring to fig. 2, fig. 2 is a second schematic structural diagram of an automatic calibration device according to an embodiment of the present invention;
in some embodiments of the present invention, optionally, the method further includes:
a first ranging rod 14 and a second ranging rod 15, wherein one end of the first ranging rod 14 is connected with a first end of the electric slide rail 11, one end of the second ranging rod 15 is connected with a second end of the electric slide rail 11, and the other end of the first ranging rod 14 is connected with the other end of the second ranging rod 15;
the connecting end of the first distance measuring ruler 14 and the second distance measuring ruler 15 is arranged right below the camera 100, and is used for adjusting the horizontal distance between the camera 100 and the calibration board 13;
the first distance measuring ruler 14, the second distance measuring ruler 15 and the electric slide rail 11 form an isosceles triangle.
In the embodiment of the invention, the automatic calibration device further comprises a first ranging rule and a second ranging rule, the first ranging rule, the second ranging rule and the electric slide rail form an isosceles triangle, and the connecting end of the first ranging rule and the second ranging rule is positioned right below the camera, so that the adjustment of the horizontal distance between the camera and the calibration plate is simply, conveniently, quickly and flexibly realized.
Referring to fig. 2, the camera 100 of fig. 2 is fixed on a vertical rod, the automatic calibration device is disposed on the ground on one side of the camera, the connecting end of the first distance rod and the second distance rod of the automatic calibration device is located right below the camera, and the two distance rods have the same length.
In some embodiments of the present invention, optionally, the first ranging rod 14 and the second ranging rod 15 each include: an inner ruler and an outer ruler;
the inner rule is nested in the outer rule for stretching the inner rule from the outer rule to extend the length of the first or second ranging rule 14, 15.
The first ranging rod comprises a first inner rod 142 and a first outer rod 141;
the second distance ruler comprises a second inner ruler 152 and a second outer ruler 151.
In an embodiment of the present invention, the first ranging rod and the second ranging rod each include: the inner ruler is nested in the outer ruler, the length of the corresponding distance measuring ruler can be prolonged by stretching the outer ruler, the flexible adjustment of the horizontal distance between the camera and the calibration plate is further realized, and the application scene of the automatic calibration device is optimized.
In some embodiments of the invention, optionally, a bolt is adopted at the joint of the electric slide rail and the ranging rod, so that sufficient mobility is maintained, and adverse effects of the environment can be eliminated to the maximum extent.
In some embodiments of the present invention, optionally, the method further includes: 3 electronic lift post 16 sets up respectively first ranging rod 14 with the bottom of the link of second ranging rod 15 with the bottom at electronic slide rail 11 both ends is used for adjusting calibration plate 13's horizontality.
In the embodiment of the invention, the automatic calibration device further comprises electric lifting columns positioned at the bottoms of three vertexes of an isosceles triangle formed by the first ranging ruler, the second ranging ruler and the electric sliding rail, and the automatic calibration device is matched with a measuring instrument arranged on a measuring instrument panel to realize the adjustment of the horizontal state of the calibration plate, so that the automation level of the automatic calibration device is improved.
In some embodiments of the present invention, optionally, the measuring instrument includes at least one of:
a level gauge installed on the gauge dial 12 for measuring a level state of the calibration plate 13;
the azimuth meter is arranged on the measuring instrument panel 12 and used for measuring the azimuth angle of the calibration plate 13;
a Real Time Kinematic (RTK) device, installed on the measurement instrument panel 12, for measuring an actual spatial position of a boundary point of a preset checkerboard in the checkerboard coordinate system.
In the embodiment of the invention, a level meter for measuring the horizontal state of the calibration plate, an azimuth meter for measuring the azimuth angle of the calibration plate and/or an RTK device for measuring the actual spatial position of the boundary point of the preset checkerboard on the calibration plate can be installed on the measurement instrument panel, so that the acquisition of necessary data during the automatic calibration of the automatic calibration device can be flexibly realized.
Referring to fig. 3, fig. 3 is a schematic structural diagram of a checkerboard coordinate system of an automatic calibration device according to an embodiment of the present invention;
and taking boundary points of a preset checkerboard in the checkerboard coordinate system as an original point, establishing an X axis in the transverse direction of the checkerboard, establishing a Y axis in the longitudinal direction of the checkerboard, and establishing a Z axis in the direction perpendicular to the calibration board.
Referring to fig. 4, fig. 4 is a schematic flow chart of an automatic calibration method according to an embodiment of the present invention. The embodiment of the invention also provides an automatic calibration method, which is applied to the automatic calibration device in any one of the embodiments, and the method comprises the following steps:
step 41: adjusting the calibration plate 13 to be vertical to the horizontal plane according to the horizontal state of the calibration plate 13 measured by the measuring instrument;
step 42: controlling the calibration plate 13 to slide on the electric slide rail 11 at a constant speed, and controlling the camera 100 to shoot the calibration plate 13 to obtain a plurality of shot images; the shot image comprises a first image when the boundary point of the preset checkerboard passes through the fixed position of the measuring instrument panel;
step 43: calculating calibration parameters of the camera 100 according to the boundary points of the checkerboards in the checkerboard coordinate system, the side lengths of the checkerboards and the shot images;
step 44: converting a camera coordinate system of the camera 100 into a world coordinate system according to the first image, the azimuth angle measured by the measuring instrument and the actual spatial position of the boundary point of the preset checkerboard;
step 45: and calculating the actual space position of any point under the camera coordinate system under the world coordinate system according to the calibration parameters of the camera.
In the embodiment of the invention, aiming at the automatic calibration device of the camera with a fixed installation position, firstly, the calibration plate is adjusted to be vertical to the horizontal plane according to the horizontal state of the calibration plate measured by a measuring instrument; then controlling the calibration plate to slide on the electric sliding rail at a constant speed, and controlling a camera to shoot the calibration plate to obtain a plurality of shot images, wherein the shot images comprise a first image when boundary points of a preset checkerboard pass through a fixed position of a dial plate of the measuring instrument; calculating calibration parameters of the camera according to boundary points of a plurality of chequers in a chequer coordinate system, the side length of the chequers and a plurality of shot images; converting a camera coordinate system of the camera into a world coordinate system according to the first image, the azimuth angle measured by the measuring instrument and the actual spatial position of the boundary point of the preset checkerboard; and calculating the actual space position of any point under the camera coordinate system under the world coordinate system according to the calibration parameters of the camera. The calibration parameters of the camera are calculated by shooting images of a plurality of calibration plates on the electric slide rail, the camera coordinate system is converted into a world coordinate system through the first image and the actual spatial position of the boundary point of the preset checkerboard, and any point on the image shot by the camera is obtained to obtain the actual spatial position of the point. The automatic calibration method is suitable for camera calibration at a fixed position under a complex environment working condition, and has high automation degree and strong adjustability.
In some embodiments of the present invention, optionally, before adjusting the calibration plate to be perpendicular to the horizontal plane according to the horizontal state of the calibration plate measured by the measuring instrument, the method further includes:
and installing the automatic calibration device to enable the distances from the two ends of the electric slide rail of the automatic calibration device to the position right below the camera to be equal.
In some embodiments of the present invention, optionally, the automatic calibration apparatus further includes: the 2 electric lifting columns 16 are respectively arranged at the bottoms of the two ends of the electric sliding rail 11 and are used for adjusting the horizontal state of the calibration plate 13;
the adjusting the calibration plate 13 to be perpendicular to the horizontal plane according to the horizontal state of the calibration plate 13 measured by the measuring instrument includes:
mounting a level gauge on the measuring instrument panel 12, and measuring the horizontal state of the calibration plate 13;
according to the horizontal state of the calibration plate 13, the electric lifting column 16 is automatically adjusted to enable the calibration plate 13 to be vertical to the horizontal plane.
In some embodiments of the present invention, optionally, the automatic calibration apparatus further includes:
a first ranging rod 14 and a second ranging rod 15, wherein one end of the first ranging rod 14 is connected with a first end of the electric slide rail 11, one end of the second ranging rod 15 is connected with a second end of the electric slide rail 11, and the other end of the first ranging rod 14 is connected with the other end of the second ranging rod 15; the connecting end of the first distance measuring ruler 14 and the second distance measuring ruler 15 is arranged right below the camera 100, and is used for adjusting the horizontal distance between the camera 100 and the calibration board 13; the first distance measuring ruler 14, the second distance measuring ruler 15 and the electric slide rail 11 form an isosceles triangle;
the 3 electric lifting columns 16 are respectively arranged at the bottoms of the connecting ends of the first ranging ruler 14 and the second ranging ruler 15 and the bottoms of the two ends of the electric sliding rail 11 and are used for adjusting the horizontal state of the calibration plate 13;
the adjusting the calibration plate 13 to be perpendicular to the horizontal plane according to the horizontal state of the calibration plate 13 measured by the measuring instrument includes:
mounting a level gauge on the measuring instrument panel 12, and measuring the horizontal state of the calibration plate 13;
according to the horizontal state of the calibration plate 13, the electric lifting column 16 is automatically adjusted to enable the calibration plate 13 to be vertical to the horizontal plane.
In the embodiment of the invention, the automatic calibration device is also provided with electric lifting columns arranged at the bottoms of the two ends of the electric sliding rail, the horizontal state of the calibration plate is measured by mounting a level gauge on a measurement instrument panel, and the electric lifting columns are automatically adjusted to ensure that the calibration plate is vertical to the horizontal plane according to the horizontal state of the calibration plate. The adjustment of the horizontal state of the calibration plate is realized, and the automation level of the automatic calibration device is improved.
In some embodiments of the present invention, optionally, the controlling the calibration plate 13 to slide on the electric slide rail 11 at a constant speed, and controlling the camera 100 to shoot the calibration plate 13 to obtain a plurality of shot images includes:
controlling the calibration plate 13 to reciprocate on the electric slide rail 11 for a plurality of times at a constant speed, and controlling the camera 100 to shoot a motion video of the calibration plate 13;
and extracting a plurality of frame images from the motion video.
In the embodiment of the invention, a plurality of shot images are extracted from the motion video shot by the camera, so that the plurality of shot images are simply and directly obtained, and the calculation of the calibration parameters of the camera is further optimized.
In some embodiments of the present invention, optionally, the meter dial 12 is horizontally suspended and fixed at the midpoint of the electric slide rail 11;
the first image is an image when the boundary point of the preset checkerboard passes through the midpoint position of the electric slide rail 11.
In the embodiment of the invention, when the dial plate of the measuring instrument is fixed at the midpoint position of the electric slide rail, in the shot first image, the boundary point of the preset checkerboard is also located at the midpoint position of the electric slide rail, the image distortion is small, and the calculated calibration parameters are more accurate; and converting the camera coordinate system into a world coordinate system according to the actual space positions of the first image and the boundary points of the preset checkerboard is simpler, more convenient and more direct.
In some embodiments of the present invention, optionally, after calculating the calibration parameters of the camera 100 according to the checkerboard coordinate system and the plurality of captured images, the method further includes:
calculating a back projection error based on the calibration parameters;
adjusting the calibration position of the shot image according to the back projection error;
and outputting the calibrated shot image for manual verification.
In the embodiment of the invention, the back projection error can be further calculated after the calibration parameters of the camera are obtained through calculation of a plurality of shot images, the calibration position of the shot images is adjusted according to the back projection error, the calibrated shot images are verified manually, and the calibration parameters and the camera calibration effect of the camera are further optimized.
In some embodiments of the present invention, optionally, the calibration parameter includes at least one of the following: the camera 100 internal parameters, distortion coefficients, rotation matrices, and translation vectors.
In the embodiment of the invention, the calibration parameters comprise internal parameters, distortion coefficients, rotation matrixes, translation vectors and the like of the camera.
Specifically, in some embodiments of the present invention, optionally, the electric slide rail may slide laterally at a preset time, and automatically stop for 3 seconds when the boundary (left boundary or right boundary) of the calibration board passes through the midpoint of the electric slide rail, so as to ensure the clarity of the image acquired at this position; the automatic calibration method comprises the following steps:
(1) mounting and fixing of automatic calibration device
The automatic calibration device is installed and fixed, the distance of each grid of the calibration plate is recorded as a first distance, and the moving time of the calibration plate on the electric sliding rail is set to be T.
(2) Checkerboard coordinate acquisition
And starting a preset calibration program, automatically and sequentially opening a level gauge, an azimuth gauge (and RTK), respectively measuring whether a current calibration plate is horizontal, if the level gauge displays that the current device is in a non-horizontal state, automatically adjusting the electric lifting column according to the data of the level gauge to reach the horizontal state, calibrating the angle value of the plate and the actual spatial position of a preset boundary point of the calibration plate, and automatically recording the angle value of the calibration plate and the actual spatial position of the preset boundary point to provide necessary data support for subsequent coordinate system conversion.
(3) Automatic calibration initiation
And after the pre-calibration program is finished, automatically and remotely starting the camera to shoot, so that the calibration plate on the slide rail runs from the leftmost end to the rightmost end at a constant speed, repeatedly and repeatedly runs back and forth for multiple times, shooting and storing a clear video to be calibrated, and stopping running the equipment and uploading video data.
(4) Data parsing and calibration parameter acquisition
For the obtained video data, an Opencv (a cross-platform computer vision and machine learning software library based on BSD license) tool box is used for respectively extracting frames, calibrating (calculating to obtain internal parameters, distortion coefficients, a rotation matrix and a translation vector), back projecting and calculating errors, and outputting a calibrated coordinate system image (used for manually verifying whether calibration is accurate).
The number of the frames (namely the number of the pictures for calibration) can be selected from 15-30 according to the field shooting condition, so that the accuracy of the calibration parameters is improved; after calibration is finished, the error of back projection (namely, the point in the actual space coordinate system is projected to the pixel coordinate system) can be calculated based on the calibration parameters, the calibration process is adjusted according to the error, and finally, a calibration image is output for manual verification.
(5) Coordinate system conversion
Based on the obtained internal and external parameters, if the camera coordinate system needs to be converted into a world coordinate system, the actual spatial position (in a cartesian coordinate system) of each point in the camera coordinate system can be calculated by using the camera imaging principle for the first distance and the angle value of the calibration plate. Since the actual spatial position is the origin of the coordinate system, the origin of the coordinate system is only required to be replaced by the actual spatial position, and the position of any spatial point in the world coordinate system (such as GPS) can be obtained.
Referring to fig. 5, fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present invention; the embodiment of the present invention provides an electronic device 50, which includes a memory 51, a processor 52, and a program stored in the memory 51 and capable of running on the processor 52; the processor 52 executes the program to implement the steps of the automatic calibration method according to any one of the above embodiments.
The embodiment of the present invention further provides a readable storage medium, where a program is stored on the readable storage medium, and when the program is executed by a processor, the program implements each process of the above-described automatic calibration method embodiment, and can achieve the same technical effect, and in order to avoid repetition, details are not described here again. The readable storage medium may be any available medium or data storage device that can be accessed by a processor, including but not limited to magnetic memory (e.g., floppy disk, hard disk, magnetic tape, magneto-optical disk (MO), etc.), optical memory (e.g., CD, DVD, BD, HVD, etc.), and semiconductor memory (e.g., ROM, EPROM, EEPROM, nonvolatile memory (NAND FLASH), Solid State Disk (SSD)), etc.
While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (12)
1. An automatic calibration device, which is used for automatically calibrating a camera with a fixed installation position, comprises: the device comprises an electric slide rail, a measuring instrument panel and a calibration plate;
the calibration plate is arranged on the electric slide rail and can move along the electric slide rail, and a checkerboard coordinate system is arranged on the calibration plate;
the measuring instrument panel is horizontally suspended and fixed on the electric sliding rail and is used for installing a measuring instrument for measuring the horizontal state and the azimuth angle of the calibration plate and the actual spatial position of the boundary point of the preset checkerboard in the checkerboard coordinate system;
the automatic calibration device further comprises:
one end of the first ranging rod is connected with the first end of the electric slide rail, one end of the second ranging rod is connected with the second end of the electric slide rail, and the other end of the first ranging rod is connected with the other end of the second ranging rod;
the connecting end of the first ranging rod and the second ranging rod is arranged right below the camera and used for adjusting the horizontal distance between the camera and the calibration plate;
the first distance measuring ruler, the second distance measuring ruler and the electric slide rail form an isosceles triangle.
2. The automatic calibration device of claim 1, wherein the first ranging rod and the second ranging rod each comprise: an inner ruler and an outer ruler;
the inner ruler is nested in the outer ruler and used for stretching the inner ruler from the outer ruler to prolong the length of the first ranging ruler or the second ranging ruler.
3. The automatic calibration device according to claim 1, further comprising: 3 electric lifting columns are respectively arranged at the bottom of the connecting end of the first ranging rod and the bottom of the connecting end of the second ranging rod and at the bottom of the two ends of the electric sliding rail and used for adjusting the horizontal state of the calibration plate.
4. The automatic calibration device according to claim 1, wherein the measuring instrument comprises at least one of:
the level gauge is arranged on the measuring instrument panel and used for measuring the horizontal state of the calibration plate;
the azimuth instrument is arranged on the measuring instrument panel and used for measuring the azimuth angle of the calibration plate;
and the real-time dynamic difference device is arranged on the measurement instrument panel and is used for measuring the actual spatial position of the boundary point of the preset checkerboard in the checkerboard coordinate system.
5. An automatic calibration method, applied to the automatic calibration apparatus according to any one of claims 1 to 4, the method comprising:
adjusting the calibration plate to be vertical to the horizontal plane according to the horizontal state of the calibration plate measured by a measuring instrument;
controlling the calibration plate to slide on the electric slide rail at a constant speed, and controlling a camera to shoot the calibration plate to obtain a plurality of shot images; the shot image comprises a first image when the boundary point of the preset checkerboard passes through the fixed position of the measuring instrument panel;
calculating calibration parameters of the camera according to the checkerboard coordinate system and the plurality of shot images;
converting a camera coordinate system of the camera into a world coordinate system according to the first image, the azimuth angle measured by the measuring instrument and the actual spatial position of the boundary point of the preset checkerboard;
and calculating the actual space position of any point under the camera coordinate system under the world coordinate system according to the calibration parameters of the camera.
6. The automatic calibration method according to claim 5, wherein the automatic calibration device further comprises:
one end of the first ranging rod is connected with the first end of the electric slide rail, one end of the second ranging rod is connected with the second end of the electric slide rail, and the other end of the first ranging rod is connected with the other end of the second ranging rod; the connecting end of the first ranging rod and the second ranging rod is arranged right below the camera and used for adjusting the horizontal distance between the camera and the calibration plate; the first distance measuring ruler, the second distance measuring ruler and the electric slide rail form an isosceles triangle;
the 3 electric lifting columns are respectively arranged at the bottoms of the connecting ends of the first ranging ruler and the second ranging ruler and at the bottoms of the two ends of the electric sliding rail and are used for adjusting the horizontal state of the calibration plate;
the adjusting the calibration plate to be perpendicular to the horizontal plane according to the horizontal state of the calibration plate measured by the measuring instrument comprises:
mounting a level gauge on the measuring instrument panel, and measuring the horizontal state of the calibration plate;
and automatically adjusting the electric lifting column to enable the calibration plate to be vertical to the horizontal plane according to the horizontal state of the calibration plate.
7. The automatic calibration method according to claim 5, wherein the controlling the calibration plate to slide on the electric slide rail at a constant speed and the controlling the camera to shoot the calibration plate to obtain a plurality of shot images comprises:
controlling the calibration plate to reciprocate on the electric slide rail for multiple times at a constant speed, and controlling a camera to shoot a motion video of the calibration plate;
and extracting a plurality of frame images from the motion video to be used as the shot images.
8. The automatic calibration method according to claim 5, wherein the measuring instrument panel is horizontally suspended and fixed at the midpoint of the electric slide rail;
the first image is an image when the boundary point of the preset checkerboard passes through the midpoint position of the electric slide rail.
9. The automatic calibration method according to claim 5, wherein after calculating calibration parameters of the camera according to the checkerboard coordinate system and the plurality of captured images, the method further comprises:
calculating a back projection error based on the calibration parameters;
adjusting the calibration position of the shot image according to the back projection error;
and outputting the calibrated shot image for manual verification.
10. The automatic calibration method according to claim 5, wherein the calibration parameters comprise at least one of: the camera comprises internal parameters, distortion coefficients, a rotation matrix and translation vectors.
11. An electronic device comprising a memory, a processor, and a program stored on the memory and executable on the processor; characterized in that the processor, when executing the program, implements the steps in the automatic calibration method according to any one of claims 5 to 10.
12. A readable storage medium, on which a program is stored, which program, when being executed by a processor, carries out the steps of the automatic calibration method as claimed in one of claims 5 to 10.
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| CN104897051B (en) * | 2014-03-03 | 2019-01-11 | 卡尔蔡司显微镜有限责任公司 | For measuring the calibration plate and its application method of calibration to digit microscope |
| CN106504290B (en) * | 2016-10-20 | 2019-10-18 | 北京化工大学 | A kind of high-precision video camera dynamic calibrating method |
| CN107817005B (en) * | 2017-10-09 | 2020-01-24 | 大连理工大学 | Integrated flexible experimental method for monocular pose measurement accuracy evaluation |
| CN111681286B (en) * | 2020-06-09 | 2023-11-28 | 商汤集团有限公司 | Calibration method, device, system, electronic equipment and storage medium |
| CN112229323B (en) * | 2020-09-29 | 2022-07-05 | 华南农业大学 | Six-degree-of-freedom measurement method of checkerboard cooperative target based on monocular vision of mobile phone and application of six-degree-of-freedom measurement method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104764441A (en) * | 2015-04-13 | 2015-07-08 | 公安部交通管理科学研究所 | Rapid calibration equipment and system for road traffic accident field measurement |
| CN112333443A (en) * | 2020-11-24 | 2021-02-05 | 苏州协尔智能光电有限公司 | Lens performance detection system and method |
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