CN108362266B - Auxiliary monocular vision measurement method and system based on EKF laser ranging - Google Patents

Auxiliary monocular vision measurement method and system based on EKF laser ranging Download PDF

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CN108362266B
CN108362266B CN201810153905.0A CN201810153905A CN108362266B CN 108362266 B CN108362266 B CN 108362266B CN 201810153905 A CN201810153905 A CN 201810153905A CN 108362266 B CN108362266 B CN 108362266B
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range finder
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CN108362266A (en
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朱庄生
袁学忠
刘刚
李建利
顾宾
王世博
邹思远
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Beihang University
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C11/00—Photogrammetry or videogrammetry, e.g. stereogrammetry; Photographic surveying
    • G01C11/02—Picture taking arrangements specially adapted for photogrammetry or photographic surveying, e.g. controlling overlapping of pictures
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only

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Abstract

The invention discloses an EKF laser ranging-based auxiliary monocular vision measurement method and device, and the method comprises the following steps: the camera is rigidly connected with the laser range finder, and a target with a diffuse reflection area and luminous characteristic points on the surface is designed and can be matched with the vision and the laser range finder for use; then, obtaining coordinates of the characteristic points on the target and a distance value measured by the laser range finder by using visual measurement, and obtaining coordinates of a light emitting point of the laser range finder in a camera coordinate system and a cosine value of the direction of an optical axis of the laser range finder by using an EKF method; and finally, correcting the position and the posture of the target plane relative to the camera coordinate system, which are measured by the camera, by using the distance data measured by the laser range finder. The device comprises a camera, a laser range finder, a target and a measuring module. The method and the device can be used for carrying out high-precision pose measurement on the object at night.

Description

Auxiliary monocular vision measurement method and system based on EKF laser ranging
Technical Field
The invention relates to the technical field of monocular vision measurement, in particular to an EKF laser ranging-based auxiliary monocular vision measurement method and system.
Background
The monocular vision measurement is to acquire the picture of the measured object through a camera and process the picture information to acquire the position and posture information of the measured object. Monocular vision measurement is widely used due to its characteristics such as non-contact measurement and simple operation. When the vision is used in night environment, a light source needs to be equipped, and a backlight type light source made of glass is generally used in the application situation of long distance and small target.
In monocular vision measurement, due to the limitation of a model, the displacement measurement precision in the direction of the optical axis of a camera is generally far lower than that in the direction perpendicular to the optical axis, and in order to improve the displacement measurement precision in the direction of the optical axis of the camera, a high-precision laser range finder is additionally arranged in the direction of the optical axis of the camera. The laser range finder can accurately measure the distance between the laser point and the light emitting point of the laser range finder by projecting the laser point on the surface of the measured object. However, the measurement precision of the laser range finder is affected by the surface material of the measured object, the laser points are printed on the glass, and the measurement data is inaccurate, so that the laser range finder cannot directly assist monocular vision measurement in a dark light environment, and the accuracy of the monocular vision measurement is greatly reduced.
Disclosure of Invention
The invention provides an EKF laser ranging-based auxiliary monocular vision measurement method and system, and aims to solve the problems.
The technical scheme of the invention is as follows:
the invention provides an EKF (extended Kalman Filter) based laser ranging assisted monocular vision measurement method, which comprises the following steps:
rigidly fixing a camera with a laser range finder, and designing a target with a diffuse reflection area and luminous characteristic points on the surface, wherein the diffuse reflection area is used for reflecting laser emitted by the laser range finder;
establishing a coordinate relation between the camera and the laser range finder based on an EKF method;
and transferring the measured data of the laser range finder to a camera coordinate system of the camera according to the coordinate relation, and correcting the optical axis coordinate of the characteristic point measured by the camera.
Preferably, the step of designing a target having a surface provided with feature points and diffuse reflection areas includes the steps of:
the backlight type laser range finder is characterized in that a backlight source type target made of glass materials is designed, a plurality of luminous array circles which are distributed in an even lattice mode are arranged on the surface of the target and serve as characteristic points, the area, outside the characteristic points, of the surface of the target is a diffuse reflection area, and a reflection film is plated on the diffuse reflection area and used for reflecting laser with the wavelength used by the laser range finder.
Preferably, the step of establishing the coordinate relationship of the camera and the laser range finder based on the EKF method comprises the steps of:
the state model for establishing the EKF method is as follows:
Figure BDA0001580641180000021
wherein the content of the first and second substances,
Figure BDA0001580641180000022
the cosine value of an included angle between a direction vector of a connecting line of the laser range finder light-emitting point and the origin of the camera coordinate system and an optical axis direction vector of the laser range finder is a three-dimensional coordinate of the laser range finder light-emitting point in the camera coordinate system;
the measurement model for establishing the EKF method comprises the following steps:
Figure BDA0001580641180000023
wherein, L is the measuring value of the laser range finder, and M is the distance between the laser object point and the origin of the camera coordinate system. Here, Z is a parameter commonly used in kalman filtering to represent a measurement, and a person skilled in the art should be able to clearly distinguish the parameter from the Z axis of the coordinate system, and is not the same technical concept.
Preferably, the step of transferring the measured data of the laser range finder to a camera coordinate system of the camera according to the coordinate relationship, and correcting the optical axis coordinate of the feature point measured by the camera includes the steps of:
acquiring a vector relation between the laser point and the characteristic point by using the laser point coordinate and the characteristic point coordinate on the target, and then calculating coordinate data of the characteristic point in the Z-axis direction by a cosine theorem;
taking X, Y axial direction coordinates obtained by the measurement of a camera and optical axial coordinates calculated by a cosine law as new three-dimensional coordinates of the feature points, establishing a vector by the three feature points, and calculating a new posture:
Figure BDA0001580641180000024
wherein the content of the first and second substances,
Figure BDA0001580641180000031
to activateThe three-dimensional coordinates of the light point in the camera coordinate system,
Figure BDA0001580641180000032
for the X, Y axis coordinates measured by the camera,
Figure BDA0001580641180000033
the updated Z-axis coordinate;
Figure BDA0001580641180000034
is the object coordinate of the feature point.
The invention also provides an EKF-based laser ranging assisted monocular vision measuring device, which comprises a camera, a laser range finder, a target and a measuring module;
the camera is rigidly connected with the laser range finder;
the surface of the target is provided with a diffuse reflection area and luminous characteristic points, and the diffuse reflection area is used for reflecting laser emitted by the laser range finder;
the measuring module is used for establishing a coordinate relation between the camera and the laser range finder based on an EKF method; and according to the coordinate relation, transferring the measured data of the laser range finder to a camera coordinate system of the camera, and correcting the optical axis coordinate of the characteristic point measured by the camera.
Preferably, the target is a backlight source type target made of a glass material, a plurality of luminous array circles distributed in a uniform lattice manner are arranged on the surface of the target and serve as characteristic points, the area of the surface of the target, outside the characteristic points, is a diffuse reflection area, and the diffuse reflection area is plated with a diffuse reflection film and used for reflecting laser with the wavelength used by the laser range finder.
Preferably, the measurement module is configured to:
the state model for establishing the EKF method is as follows:
Figure BDA0001580641180000035
wherein the content of the first and second substances,
Figure BDA0001580641180000036
the cosine value of an included angle between a direction vector of a connecting line of the laser range finder light-emitting point and the origin of the camera coordinate system and an optical axis direction vector of the laser range finder is a three-dimensional coordinate of the laser range finder light-emitting point in the camera coordinate system;
the measurement model for establishing the EKF method comprises the following steps:
Figure BDA0001580641180000037
wherein, L is the measuring value of the laser range finder, and M is the distance between the laser object point and the origin of the camera coordinate system.
Preferably, the measurement module is configured to:
acquiring a vector relation between the laser point and the characteristic point by using the laser point coordinate and the characteristic point coordinate on the target, and then calculating coordinate data of the characteristic point in the Z-axis direction by a cosine theorem;
taking X, Y axial direction coordinates obtained by the measurement of a camera and optical axial coordinates calculated by a cosine law as new three-dimensional coordinates of the feature points, establishing a vector by the three feature points, and calculating a new posture:
Figure BDA0001580641180000041
wherein the content of the first and second substances,
Figure BDA0001580641180000042
is the three-dimensional coordinate of the laser point in the camera coordinate system,
Figure BDA0001580641180000043
for the X, Y axis coordinates measured by the camera,
Figure BDA0001580641180000044
the updated Z-axis coordinate;
Figure BDA0001580641180000045
is the object coordinate of the feature point.
The invention discloses the technical effects that:
the invention provides a night laser ranging auxiliary monocular vision measuring method based on Extended Kalman Filtering (EKF), aiming at the problem that the monocular vision measuring camera optical axis direction position precision is low, the laser ranging auxiliary vision method is adopted to improve the camera optical axis direction position measuring precision; the special design of the target can be used as a target for visual measurement and a target for measurement of a laser range finder, so that the problem of incompatibility of laser range finding and the visual target is solved; based on an EKF method, a coordinate relation between a camera and a laser range finder is established, and measured data of the laser range finder is transferred to a camera coordinate system, and an optical axis coordinate of a characteristic point measured by the camera is corrected, so that the problem that relative pose information of the camera and the laser range finder is complex to obtain in traditional laser range finding auxiliary visual measurement is solved, the pose relation between the camera and the laser range finder is obtained based on the EKF method, the problem that the laser range finding and the camera measuring data have no unified reference is solved, and the precision of data fusion is improved. Furthermore, a backlight type coating target is designed, the problem that a laser range finder cannot be used at night is solved, and the application range of laser range finding auxiliary visual measurement is widened.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
FIG. 1 is a schematic structural diagram of an embodiment of an EKF-based laser ranging assisted monocular vision measuring device of the present invention;
FIG. 2 is a schematic diagram of a target according to an embodiment of the present invention based on an EKF laser ranging assisted monocular vision measurement method;
FIG. 3 is a schematic flow chart of an embodiment of the method for assisted monocular vision measurement based on EKF laser ranging according to 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 only a part of the embodiments of the present invention, and not all of the embodiments. 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.
The invention discloses an EKF laser ranging-based auxiliary monocular vision measurement method and device. Firstly, designing an auxiliary target for night use, which can be used in cooperation with vision and a laser range finder at the same time; then, obtaining coordinates of the characteristic points on the target and a distance value measured by the laser range finder by using visual measurement, and obtaining coordinates of a light emitting point of the laser range finder in a camera coordinate system and a cosine value of the direction of an optical axis of the laser range finder by using an EKF method; and finally, correcting the position and the posture of the target plane relative to the camera coordinate system, which are measured by the camera, by using the distance data measured by the laser range finder.
Referring to fig. 1, the apparatus for implementing EKF-based laser ranging assisted monocular vision measurement mainly comprises 3 parts, a camera 110, a laser range finder 111 and a target 112. In the working process, the target 112 is fixed, the camera 110 is fixedly connected with the laser range finder 111, the point of the laser range finder 111 is hit at the non-feature point of the target, and the camera shoots the target image.
Among them, as for the target, in order to satisfy the nighttime recognition, only a glass material is used for the backlit target. However, the glass material cannot be used in the laser range finder, and in view of this, the design of the auxiliary target of the present invention, as shown in fig. 2, is an implementation manner that a standard dot matrix target is adopted and processed into a backlight type, that is, the backlight type dot matrix target is made of the glass material. The array circle on the surface of the target emits light as a characteristic point, the rest areas do not emit light, a special film is coated on the non-light-emitting area on the surface of the target to form a diffuse reflection area (namely a coating area in figure 2), and the characteristic of the film is to reflect the light with the wavelength used by the laser range finder. This satisfies both vision and laser rangefinder applications. The target surface is therefore coated with a special thin film which is characteristic of reflecting the light of the laser wavelength used by the laser rangefinder. Thus the target can satisfy the application of vision and laser range finder at the same time.
An embodiment of the present invention for performing laser ranging assisted monocular vision measurements based on the EKF method is described in detail below.
Firstly, acquiring a pose relation between a camera coordinate system and a laser range finder by using an Extended Kalman Filter (EKF) method to realize the unification of the coordinate system, which specifically comprises the following steps:
(1) laser spot camera coordinate system coordinate acquisition
The origin of the camera coordinate system is set as Oc(0,0, 0); the coordinates of the laser light emitting point are set as
Figure BDA0001580641180000061
The distance between the laser light emitting point D and the origin of the camera coordinate system is
Figure BDA0001580641180000062
The coordinate of the laser point S in the camera coordinate system is
Figure BDA0001580641180000063
The measured value of the laser range finder is L;
Figure BDA0001580641180000064
the characteristic points are 4 known space coordinates on the target plane, and the space coordinates of the characteristic points in the target coordinate system are respectively
Figure BDA0001580641180000065
The corresponding coordinates of the image point are respectively (u)i,vi) And i is 1,2,3, 4. Points on a plane
Figure BDA0001580641180000066
Corresponding image point (u) thereofi,vi) Satisfies the following projection model:
Figure BDA0001580641180000067
writing in matrix form:
Figure BDA0001580641180000068
2 formulas can be established for each point coordinate on the plane, and 8 projection transformation parameters a of the plane can be solved in real time by using 4 points which are not on the same straight line0,a1,a2,b0,b1,b2,c1,c2。
Then the coordinates (u) of the image point of the laser spot SS,vS) Substituting the formula to obtain the coordinates of the laser spot S in the world coordinate system
Figure BDA0001580641180000069
Figure BDA00015806411800000610
The rotation translation R, T and R measured by the camera are direction cosine matrixes formed by three-axis Euler angles of a target coordinate system relative to a camera coordinate system, and T is the three-axis position of an origin of the target coordinate system relative to the origin of the camera coordinate system. The coordinates of the laser point S in the camera coordinate system can be obtained:
Sc＝RSw+T
the projection model is derived from the camera imaging model,
Figure BDA0001580641180000071
to represent
Figure BDA0001580641180000072
And (u)i,vi) In the above formula fx,fyFor camera intrinsic parameters, trij(i, j ═ 1,2,3) th row and j column of conversion matrix tr composed of camera extrinsic parametersAnd (4) elements. When the internal and external parameters of the camera are unknown, a0,a1,a2,b0,b1,b2,c1,c2Are parameters for substitution.
(2) Then, establishing a filtering state equation, and taking the laser light-emitting point coordinate and the laser optical axis cosine value to be solved as filtering state quantities:
Figure BDA0001580641180000073
state transition matrix:
Figure BDA0001580641180000074
and (3) updating the filtering time:
xk+1/k＝Fkxk
Pk+1/k＝FkPkFk+Qk
in the above formula, xk+1/kState x at time k +1kOne step of predicting value of, Pk+1/kAnd predicting the mean square error matrix for the k +1 moment by one step. PkEstimating a mean square error matrix, Q, for a k-th time instantkIs the system noise variance matrix at the k time.
(3) Establishing a filtering measurement equation, taking a laser measurement distance value L and a distance M between a laser point and the origin center of a coordinate system of the camera as measurement quantities, and then:
Figure BDA0001580641180000075
Figure BDA0001580641180000081
establishing a Jacobian matrix:
Figure BDA0001580641180000082
measurement updating:
Figure BDA0001580641180000083
xk+1＝xk+1/k+Kk+1(zk+1-Hk+1xk+1/k)
Pk+1＝(I-Kk+1Hk+1)Pk+1/k
in the above formula, Kk+1For filter gain arrays, Rk+1For measuring the noise variance matrix, Hk+1A jacobian matrix of state quantities is measured for the quantities.
The position and pose relationship between the camera coordinate system and the laser range finder is obtained through the steps, and then the position and pose relationship between the camera coordinate system and the laser range finder is obtained, laser range data and monocular vision measurement position and pose data are fused, and the method specifically comprises the following steps:
firstly, the laser point S and the characteristic point A on the target are utilizediCoordinates S in the camera coordinate systemc、
Figure BDA0001580641180000084
Obtaining the vector relation between the laser point and the characteristic point
Figure BDA0001580641180000085
Figure BDA0001580641180000086
And then by laser point S, OcCoordinates of the point in a camera coordinate system to obtain a vector ScOc：
Figure BDA0001580641180000087
Calculating the included angle between the two vectors and the distance between the feature point and the origin of the camera coordinate system by the cosine theorem:
Figure BDA0001580641180000088
Figure BDA0001580641180000089
measured by a cameraiThe coordinates of the point in the camera coordinate system are
Figure BDA0001580641180000091
Keeping the X-axis and Y-axis coordinates obtained by the camera measurement, and correcting AiPoint Z axis coordinate:
Figure BDA0001580641180000092
three-dimensional coordinates corrected by four feature points
Figure BDA0001580641180000093
Calculating the attitude, taking
Figure BDA0001580641180000094
Constructing 3 vectors by points, and taking
Figure BDA0001580641180000095
3 vectors are constructed, the third vector is obtained by multiplying the difference, and only the posture relation exists between the vectors:
Figure BDA0001580641180000096
wherein, Oc(0,0,0) is the origin of the camera coordinate system.
Referring to fig. 3, the steps of the above embodiment of the present invention can be summarized as follows: measuring the target distance by a laser range finder, and shooting a target image by a camera; the EKF method obtains the pose relationship between the laser range finder and the camera coordinate system, when the EKF method works normally, the laser measurement value is transferred to the camera coordinate system through the obtained pose relationship between the laser range finder and the camera coordinate system, the Z-direction value of the feature point is calculated, the measurement value of the camera is corrected, the position data is corrected, finally, the vector is constructed by the coordinates corrected by the 3 feature points, and the attitude data is calculated.
In summary, the invention provides a night laser ranging assisted monocular vision measurement method based on Extended Kalman Filter (EKF), which adopts a special target design, a laser point of a laser range finder is arranged on a target plane, a camera shoots a target image, a pose relation between a camera coordinate system and the laser range finder is obtained by using the EKF method to realize the unification of the coordinate system, then distance data of the laser range finder is merged into pose data of monocular vision measurement, a vector relation between a laser point and a characteristic point is obtained by using a laser point coordinate and a characteristic point coordinate on a target during the joint measurement of the camera and the laser range finder, and the position data of the characteristic point is calculated by cosine theorem. And finally, taking X, Y axial direction coordinates obtained by the measurement of the camera and optical axial coordinates calculated by the cosine theorem as new three-dimensional coordinates of the characteristic points, and calculating a three-dimensional Euler angle according to the new coordinates.
The embodiment of the invention also provides an EKF-based laser ranging assisted monocular vision measuring device which comprises a camera, a laser range finder, a target and a measuring module. The camera is rigidly connected with the laser range finder; the surface of the target is provided with a diffuse reflection area and a luminous characteristic point; the measuring module is used for establishing a coordinate relation between the camera and the laser range finder based on an EKF method; and according to the coordinate relation, transferring the measured data of the laser range finder to the camera coordinate system of the camera, and correcting the optical axis coordinate of the characteristic point measured by the camera.
Therefore, the invention overcomes the problems of incompatibility of laser ranging and a visual target and complex acquisition of relative pose information of a camera and a laser range finder in the traditional laser ranging assisted visual measurement, has the characteristics of high-precision three-dimensional position and strong anti-interference capability by using the EKF method, and can be used for high-precision measurement of the three-dimensional pose of an object.
Those skilled in the art will appreciate that the invention may be practiced without these specific details. The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.

Claims (4)

1. An EKF-based laser ranging assisted monocular vision measurement method is characterized by comprising the following steps:
rigidly fixing a camera with a laser range finder, and designing a target with a diffuse reflection area and luminous characteristic points on the surface, wherein the diffuse reflection area is used for reflecting laser emitted by the laser range finder;
establishing a coordinate relation between the camera and the laser range finder based on an EKF method;
according to the coordinate relation, transferring the measured data of the laser range finder to a camera coordinate system of the camera, and correcting the optical axis coordinate of the characteristic point measured by the camera;
the step of establishing the coordinate relationship between the camera and the laser range finder based on the EKF method comprises the steps of:
the state model for establishing the EKF method is as follows:
Figure FDA0002276964000000011
wherein the content of the first and second substances,
Figure FDA0002276964000000012
the cosine value of an included angle between a direction vector of a connecting line of the laser range finder light-emitting point and the origin of the camera coordinate system and an optical axis direction vector of the laser range finder is a three-dimensional coordinate of the laser range finder light-emitting point in the camera coordinate system;
the measurement model Z for establishing the EKF method is as follows:
Figure FDA0002276964000000013
wherein, L is a measurement value of the laser range finder, and M is a distance between a laser object point and an origin of a camera coordinate system;
the step of transferring the measured data of the laser range finder to a camera coordinate system of the camera according to the coordinate relationship to correct the optical axis coordinate of the characteristic point measured by the camera includes the following steps:
acquiring a vector relation between the laser point and the characteristic point by using the laser point coordinate and the characteristic point coordinate on the target, and then calculating coordinate data of the characteristic point in the Z-axis direction by a cosine theorem;
taking X, Y axial direction coordinates obtained by the measurement of a camera and optical axial coordinates calculated by a cosine law as new three-dimensional coordinates of the feature points, establishing a vector by the three feature points, and calculating a new posture:
Figure FDA0002276964000000021
wherein the content of the first and second substances,
Figure FDA0002276964000000022
is the three-dimensional coordinate of the laser point in the camera coordinate system,
Figure FDA0002276964000000023
for the X, Y axis coordinates measured by the camera,
Figure FDA0002276964000000024
the updated Z-axis coordinate;
Figure FDA0002276964000000025
is the object coordinate of the feature point.
2. The EKF laser ranging-based assisted monocular vision measuring method of claim 1, wherein: the step of designing a target with a surface provided with characteristic points and a diffuse reflection area comprises the following steps:
the backlight type laser range finder is characterized in that a backlight source type target made of glass materials is designed, a plurality of luminous array circles which are distributed in an even lattice mode are arranged on the surface of the target and serve as characteristic points, the area, outside the characteristic points, of the surface of the target is a diffuse reflection area, and a reflection film is plated on the diffuse reflection area and used for reflecting laser with the wavelength used by the laser range finder.
3. An auxiliary monocular vision measuring device based on EKF laser ranging is characterized by comprising a camera, a laser range finder, a target and a measuring module;
the camera is rigidly connected with the laser range finder;
the surface of the target is provided with a diffuse reflection area and luminous characteristic points, and the diffuse reflection area is used for reflecting laser emitted by the laser range finder;
the measuring module is used for establishing a coordinate relation between the camera and the laser range finder based on an EKF method; according to the coordinate relation, transferring the measured data of the laser range finder to a camera coordinate system of the camera, and correcting the optical axis coordinate of the characteristic point measured by the camera;
the measurement module is configured to:
the state model for establishing the EKF method is as follows:
Figure FDA0002276964000000026
wherein the content of the first and second substances,
Figure FDA0002276964000000031
the cosine value of an included angle between a direction vector of a connecting line of the laser range finder light-emitting point and the origin of the camera coordinate system and an optical axis direction vector of the laser range finder is a three-dimensional coordinate of the laser range finder light-emitting point in the camera coordinate system;
the measurement model for establishing the EKF method comprises the following steps:
Figure FDA0002276964000000032
wherein, L is the measuring value of the laser range finder, and M is the distance between the laser object point and the origin of the camera coordinate system.
The measurement module is configured to:
acquiring a vector relation between the laser point and the characteristic point by using the laser point coordinate and the characteristic point coordinate on the target, and then calculating coordinate data of the characteristic point in the Z-axis direction by a cosine theorem;
taking X, Y axial direction coordinates obtained by the measurement of a camera and optical axial coordinates calculated by a cosine law as new three-dimensional coordinates of the feature points, establishing a vector by the three feature points, and calculating a new posture:
Figure FDA0002276964000000033
wherein the content of the first and second substances,
Figure FDA0002276964000000034
is the three-dimensional coordinate of the laser point in the camera coordinate system,
Figure FDA0002276964000000035
for the X, Y axis coordinates measured by the camera,
Figure FDA0002276964000000036
the updated Z-axis coordinate;
Figure FDA0002276964000000037
is the object coordinate of the feature point.
4. The EKF-based laser ranging assisted monocular vision measuring device according to claim 3, wherein the target is a backlight type target made of glass material, the surface of the target is provided with a plurality of luminous array circles distributed in a uniform lattice manner as feature points, the area of the surface of the target other than the feature points is a diffuse reflection area, and the diffuse reflection area is coated with a reflection film for reflecting the laser with the wavelength used by the laser range finder.
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