An environment-adaptive array target posture measurement system and method

Abstract

The present invention relates to a posture measurement system and method, and specifically to an environment-adaptive array target posture measurement system and method, which solves the technical problems that the existing array target posture measurement methods have low measurement accuracy and are difficult to achieve simultaneous and high-precision measurement of array targets. The present invention measures the posture of array targets based on laser and photogrammetry, uses a laser with known spatial posture information and a flat target to form a plurality of non-collinear laser spot centroids, obtains characteristic information of the flat target through a camera, and then performs geometric correction on the two-dimensional position information of the laser spot centroid on the flat target, and then calculates the deflection amount in the laser transmission process according to the environmental parameters on the laser light path, performs position compensation on the two-dimensional position information of the laser spot centroid, and then couples the spatial posture information of the laser beam, thereby obtaining the posture information of each flat target, and then solving the overall posture of the array target, and achieving simultaneous and high-precision measurement of the array target posture.

Description

Technical Field

[0001] The present invention relates to a posture measurement system and method, and in particular to an environment-adaptive array target posture measurement system and method. Background Art

[0002] With the rapid development of science and technology and the continuous advancement of modern production technology, in order to ensure the time uniformity and efficiency of multiple target pose measurement, the measurement task has gradually shifted from single target measurement to multi-target simultaneous measurement. For example, wind power station blades, aerospace solar photovoltaic panels, large bridge panel structures, large-aperture ground radio telescope antenna main and secondary surfaces, etc. are array targets composed of multiple flat targets, and they all require relatively fast and high-precision pose measurement at the beginning of construction, calibration or monitoring. Therefore, the demand for array target pose rapid measurement technology is becoming more and more urgent.

[0003] At present, laser trackers and machine vision measurement methods are usually used to measure the position and posture information of array targets. However, laser trackers are limited by the impact of the environment on laser transmission. Under long-distance measurement conditions, their measurement accuracy can only reach the order of 0.1mm. Although machine vision measurement methods can improve the measurement accuracy of position and posture, due to its long measurement time, it cannot meet the needs of simultaneous measurement of array targets. In addition, most of the other mainstream position and posture measurement methods currently cannot take into account the problems of achieving high-precision measurement of array targets and avoiding environmental impacts at the same time.

[0004] Therefore, there is an urgent need to design a posture measurement system and method for array targets, which can not only avoid environmental influences, but also perform simultaneous and high-precision posture measurement of array targets at medium and long distances. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problems that the existing array target posture measurement methods have low measurement accuracy and are difficult to achieve simultaneous and high-precision measurement of array targets, and to provide an environment-adaptive array target posture measurement system and method.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] An environment-adaptive array target posture measurement system, wherein the array target is composed of N flat targets, each of which has I non-collinear feature points, wherein N≥2, I≥4, and N and I are both integers; the system is special in that it includes a light source, a camera, an environment correction unit, an image processing unit, and a posture solving unit;

[0008] The light source and the camera are located on the same side of the array target, and the light source is used to emit multiple laser beams to the array target, wherein a single flat target receives J laser beams, and the coverage range of the J laser beams is greater than the movement range of the single flat target, wherein J ≥ 3 and is an integer;

[0009] The camera is electrically connected to the image processing unit, and is used to detect image information of the array target and the laser spot, and transmit a two-dimensional image of the array target to the image processing unit;

[0010] The environmental correction unit includes M groups of environmental monitoring sensors arranged in sequence along the laser light path and electrically connected to the image processing unit, the M groups of environmental monitoring sensors divide the laser light path between the light source and the array target into M+1 layers, and are used to monitor the environmental parameters between the light source and the array target in real time, wherein M is an integer greater than 0;

[0011] Each group of environmental monitoring sensors includes at least 3 thermometers and hygrometers and 3 anemometers;

[0012] The environment monitoring plane formed by the thermometer and the anemometer, the multiple laser beams emitted by the light source pass through the environment monitoring plane, and the environment monitoring plane is parallel to the array target;

[0013] The image processing unit is electrically connected to the posture solving unit, and is used to correct the two-dimensional image of the array target to obtain the two-dimensional coordinates of the centroid of the laser spot, and compensate the two-dimensional coordinates of the centroid of the laser spot according to the environmental parameters to obtain the two-dimensional coordinates of the centroid of the laser spot after environmental compensation;

[0014] The posture solving unit is used to solve the two-dimensional coordinates of the centroid of the laser spot after environmental compensation, and then fit the real-time posture of the array target.

[0015] Furthermore, 4≤I≤6, 3≤J≤6, 0<M≤L / 2.5, where L is the distance between the light source and the array target, in meters.

[0016] Furthermore, the field of view of the camera at least covers a single flat target.

[0017] The present invention also provides an environment-adaptive array target posture measurement method, which is based on the above-mentioned environment-adaptive array target posture measurement system, and is special in that it includes the following steps:

[0018] Step 1: calibrate the position of one non-collinear feature point on each flat target, establish a two-dimensional coordinate system based on the flat target, and obtain the two-dimensional coordinates of the feature point on each flat target;

[0019] Step 2: Turn on the light source, emit laser to the array target, calibrate all laser beams emitted by the light source, and obtain the equivalent spatial straight line equation of the laser beam;

[0020] Step 3: The camera collects a two-dimensional image of the array target in the current state and transmits it to the image processing unit; the image processing unit establishes a two-dimensional pixel coordinate system based on the two-dimensional image of the array target, and then obtains the centroid pixel coordinates of the feature points and laser spots on each flat target;

[0021] Step 4: The image processing unit establishes an image geometry correction model based on the two-dimensional coordinates of the feature points on each flat target obtained in step 1 and the centroid pixel coordinates of the corresponding feature points obtained in step 3; then, according to the image geometry correction model and the centroid pixel coordinates of the laser spot on each flat target obtained in step 3, the two-dimensional coordinates of the centroid of the laser spot in the two-dimensional coordinate system of the corresponding flat target are obtained;

[0022] Step 5: The environmental correction unit obtains the environmental parameters of each layer of the laser optical path and sends them to the image processing unit; the image processing unit compensates for the laser deflection caused by environmental factors during the laser transmission process according to the environmental parameters of each layer of the laser optical path, and obtains the two-dimensional coordinates of the centroid of the laser spot after environmental compensation;

[0023] Step 6, the posture solving unit calculates the spatial coordinates of the center of mass of each laser spot on each flat target based on the equivalent spatial straight line equation of the laser beam obtained in step 2 and the two-dimensional coordinates of the center of mass of the laser spot after environmental compensation obtained in step 5, and then obtains the current posture of each flat target;

[0024] Step 7: Change the position and posture of the array target, and obtain the position and posture of each flat plate target after the array target position and posture are changed according to the method of steps 3 to 6;

[0025] Step 8: The posture solving unit calculates the translation parameters and rotation parameters of the overall posture of the array target according to the current posture of each flat target and the posture of each flat target after the array target posture changes, thereby obtaining the real-time posture of the array target.

[0026] Furthermore, step 4 is specifically as follows:

[0027] 4.1. Definition: The two-dimensional coordinates of the feature point are ( x ni , y ni , 1) T , and its corresponding centroid pixel coordinates are ( x′ ni , y′ ni , 1) T ;

[0028] Then the geometric transformation relationship of the feature points is:

[0029]

[0030] in, , H n3×3 Indicates n The correction matrix for a flat plate target, n is an integer, and 1≤ n ≤N, h n11 , h n12 , h n21 and h n22 For the n The affine transformation parameters of a flat plate target, h n13 and h n23 For the n The translation transformation parameters of the flat plate target, h n31 and h n32 Indicates n The transformed edge intersection relationship of the flat plate target, h n33 For h n31 , h n32 The associated scaling factor;

[0031] ( x ni , y ni ) indicates the n Tablet target on the i The two-dimensional coordinates of the feature points, i is an integer, and 1≤ i ≤I;

[0032] ( x′ ni , y′ ni ) indicates the n Tablet target on the i The centroid pixel coordinates of feature points;

[0033] 4.2. Convert the geometric transformation relationship of the feature points to obtain:

[0034]

[0035] 4.3. Substitute the two-dimensional coordinates of the feature points on each flat target obtained in step 1 and the centroid pixel coordinates of the corresponding feature points obtained in step 3 into the formula obtained in step 4.2 to obtain the correction matrix of each flat target;

[0036] 4.4. Using the correction matrix of each flat target, convert the centroid pixel coordinates of the laser spot on each flat target obtained in step 3 into the two-dimensional coordinates of the corresponding flat target in the two-dimensional coordinate system:

[0037]

[0038] in,( x nj , y nj ) indicates the n Tablet target on the j The two-dimensional coordinates of the center of mass of the laser beam spot, j is an integer, and 1≤ j ≤J;

[0039] ( x′ nj , y′ nj ) indicates the n Tablet target on the j The pixel coordinates of the centroid of the laser beam spot.

[0040] Furthermore, step 5 is specifically as follows:

[0041] 5.1. The environmental correction unit obtains the environmental parameters of each layer of the laser optical path and sends them to the image processing unit;

[0042] 5.2. The image processing unit uses the environmental parameters of each layer of the laser light path to calculate the atmospheric refractive index of each layer of the laser light path through the following formula:

[0043]

[0044] in, N m Indicates m Layered atmospheric refractive index, m is an integer, and 1≤ m ≤M+1;

[0045] K is Kelvin temperature, K=T+273.15, T is Celsius temperature, measured by a thermometer and hygrometer;

[0046] e 0 is the saturated water vapor pressure;

[0047] p For the m The pressure of the layers is calculated based on the parameters measured by the anemometer;

[0048] Q is the m The humidity of the layers, measured by a thermohygrometer;

[0049] 5.3. Calculate the laser refraction angle of each layer of the laser optical path using the following formula:

[0050]

[0051] in, θ m Indicates m The laser refraction angle of each layer, m =1, θ m is the laser incident angle, N m+1 Indicates m+ 1 layered atmospheric refractive index, θ m+1 Indicates m+ 1 layered laser refraction angle;

[0052] 5.4. Use the laser deflection formula to calculate the laser deflection direction of each layer of the laser optical path;

[0053] 5.5. According to the laser deflection direction of each layer of the laser light path obtained in step 5.4 and the laser refraction angle of each layer of the laser light path obtained in step 5.3, calculate the offset of the laser spot centroid on the corresponding flat target, and then obtain the two-dimensional coordinates of the laser spot centroid after environmental compensation.

[0054] Furthermore, step 6 is specifically as follows:

[0055] 6.1. Based on the two-dimensional coordinates of the centroids of the laser spots after environmental compensation obtained in step 5, calculate the lengths between the centroids of the laser spots on the same flat target. Then, based on the principle that the lengths of the same spatial line segments are equal, calculate the spatial coordinates of the centroids of each laser spot on each flat target according to the equivalent spatial straight line equation of the laser beam obtained in step 2.

[0056] 6.2. Definition: Any point on a flat plate target is the origin of the flat plate target;

[0057] 6.3. Based on the two-dimensional coordinates of the centroid of the laser spot after environmental compensation obtained in step 5, calculate the length between the centroid of each laser spot on each flat target and the origin, and then use the principle that the lengths of the same spatial line segments are equal to obtain the spatial coordinates of the origin of each flat target based on the spatial coordinates of the centroid of each laser spot on the flat target;

[0058] 6.4. Based on the spatial coordinates of the origin of each flat target and the spatial coordinates of the centroid of each laser spot on the flat target, calculate the plane normal direction of the origin of each flat target, and together with the spatial coordinates of the origin of each flat target obtained in step 6.3, constitute the current posture of each flat target.

[0059] Furthermore, step 8 is specifically as follows:

[0060] 8.1. According to the current posture of each flat target and the posture of each flat target after the array target posture is changed, the translation parameter and rotation parameter of each flat target are obtained by using the seven-parameter Bursa model space three-dimensional coordinate transformation;

[0061] 8.2. According to the translation parameters of each flat target, the translation parameters of the overall position of the array target are calculated using the following formula:

[0062]

[0063] Among them, T is the translation parameter of the overall position of the array target, For the n Translation parameters of a flat plate target;

[0064] 8.3. Construct the rotation quaternion of each flat target according to the rotation parameters of each flat target:

[0065]

[0066] in, Indicates n The rotation quaternion of a flat target, [ l nx , l ny , l nz ] = L n , L n For the n The rotation parameters of a flat plate target, l nx , l ny , l nz Respectively represent n The rotation parameters of the flat plate target in the space coordinate system x axis, y axis, z The coordinates of the axes;

[0067] 8.4. The rotation quaternions of each flat target are combined into an N×4 matrix Q. The covariance matrix C of the matrix Q is calculated by the following formula:

[0068]

[0069] 8.5. Calculate the eigenvector corresponding to the maximum eigenvalue of the covariance matrix C, and then normalize it to obtain the quaternion eigenvector;

[0070] 8.6. Convert the quaternion eigenvector into a rotation matrix to obtain the rotation parameters of the overall pose of the array target, which together with the overall pose translation parameters of the array target obtained in step 8.2 constitute the real-time pose of the array target.

[0071] Furthermore, in step 1, the specific method of establishing the two-dimensional coordinate system is:

[0072] Take any feature point on the flat target as the coordinate origin, and the line connecting the coordinate origin and another feature point as x Axis, x The perpendicular line of the axis at the origin of the coordinate system is y Axis, establish a two-dimensional coordinate system.

[0073] Furthermore, in step 3, the specific method of establishing the two-dimensional pixel coordinate system is:

[0074] Take the upper left corner of the array target two-dimensional image as the coordinate origin, so x The axis is parallel to the 2D image plane and points horizontally to the right. y The axis is parallel to the 2D image plane and runs vertically downward, with one pixel value as the unit length.

[0075] Compared with the prior art, the present invention has the following beneficial technical effects:

[0076] 1. The present invention provides an environment-adaptive array target posture measurement system, which combines laser and photogrammetry to measure the posture of array targets. It can select a suitable light source and camera according to the distance of the array target to achieve non-contact measurement, thereby achieving posture measurement at various distances;

[0077] 2. In the environment-adaptive array target posture measurement system provided by the present invention, the hardware equipment only includes a light source, a camera and an environment detection unit, and the entire measurement system has low cost and strong applicability;

[0078] 3. In an environment-adaptive array target posture measurement system provided by the present invention, the environment parameters on the laser optical path can be obtained by using the environment monitoring unit, and the environment parameters are fed back to the two-dimensional image taken by the camera. The deflection of the laser is fitted by using the environment parameters during the laser transmission process, so as to realize the high-precision extraction of the spatial coordinates of the center of mass of the laser spot, thereby improving the accuracy of the measurement and reducing the influence of the environment on the measurement system;

[0079] 4. In the environment-adaptive array target posture measurement system provided by the present invention, multiple laser beams covering the array targets are used for measurement, and the simultaneous measurement of a single target or multiple targets can be completed according to requirements, thereby improving the applicability of the system;

[0080] 5. The present invention provides an environment-adaptive array target posture measurement method, which obtains the pixel information of the feature points and laser spots on the array target through a camera, and performs geometric correction and environmental correction, thereby obtaining the high-precision two-dimensional coordinates of the center of mass of the laser spot, and further couples the spatial straight line equation of the laser beam to obtain the spatial coordinates of the center of mass of the laser spot, thereby obtaining the posture information of each flat target, and then solving the overall posture of the array target, which can realize fast and high-precision posture measurement of the array target;

[0081] 6. In an environment-adaptive array target posture measurement method provided by the present invention, a two-dimensional image of an array target is directly acquired by a camera, and geometric correction of the image is achieved by using the feature points of the array target. No requirements are made on the exterior orientation parameters of the camera, which reduces the requirements on the position stability of the camera. The image distortion caused by the camera can be directly corrected by using the feature point information of the array target itself and a straight-line-based distortion parameter estimation method, thereby finally achieving adaptive calibration of the camera parameters.

[0082] 7. In an environment-adaptive array target posture measurement method provided by the present invention, a geometric correction model is established by using feature points on a flat target. Only feature points with known two-dimensional position information and not collinear are required on the flat target. Feature information of the measured target itself, such as corner points and edges, can also be directly used. The method has strong applicability and can perform posture measurement on a variety of targets.

[0083] 8. In an environment-adaptive array target posture measurement method provided by the present invention, multiple laser beams emitted by a light source form multiple non-collinear laser spots on a flat target, and a redundant plane composed of the centroids of three non-collinear laser spots can characterize the posture transformation of the flat target. The posture information of the flat target is solved by using the posture information of multiple redundant planes composed of the centroids of the laser spots, which can reduce the influence of the error of a single laser spot on the posture information of the flat target and further improve the measurement accuracy.

[0084] 9. In the environment-adaptive array target posture measurement method provided by the present invention, the quaternion mean method is used to realize the measurement of the overall posture of the array target, thereby improving the applicability of the measurement method. BRIEF DESCRIPTION OF THE DRAWINGS

[0085] Figure 1 This is a structural principle diagram of an environment-adaptive array target position and posture measurement system according to an embodiment of the present invention;

[0086] Figure 2 A schematic diagram of a two-dimensional coordinate system in step 1 of an environment-adaptive array target pose measurement method according to an embodiment of the present invention;

[0087] Figure 3A schematic diagram of a two-dimensional pixel coordinate system in step 3 of an environment-adaptive array target pose measurement method according to an embodiment of the present invention;

[0088] The following are the descriptions of the reference numerals:

[0089] 1-light source, 2-camera, 3-environmental correction unit, 4-first flat plate target, 5-second flat plate target, 6-third flat plate target, 7-array target, 8-environmental monitoring plane. DETAILED DESCRIPTION

[0090] The following is a further detailed description of an environment-adaptive array target pose measurement system and method proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. The array target targeted by the present invention is composed of N flat targets, each of which has I non-collinear feature points, where N≥2, 4≤I≤6, and N and I are both integers. The feature points can be inherent surface features or additional marks, and the two-dimensional position relationship of the feature points relative to the flat plane is known, and the array target as a whole can undergo pose transformation.

[0091] Those skilled in the art should understand that these implementation modes are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0092] An environment-adaptive array target position measurement system, such as Figure 1 As shown, it includes a light source 1, a camera 2, an environment correction unit 3, an image processing unit and a posture solving unit. The light source 1 and the camera 2 are located on the same side of the array target 7. The light source 1 is used to emit multiple laser beams to the array target 7, wherein a single flat target receives J laser beams, and the coverage range of the J laser beams is greater than the range of movement of the single flat target, wherein 3≤J≤6 and is an integer, and J is 3 in this embodiment. The camera 2 is electrically connected to the image processing unit, and is used to detect the array target 7 information and the laser spot information, and transmit the original image of the array target 7 to the image processing unit. The field of view of the camera 2 covers at least a single flat target.

[0093] The environmental correction unit 3 includes M groups of environmental monitoring sensors arranged in sequence along the laser light path and electrically connected to the image processing unit. The M groups of environmental monitoring sensors divide the laser light path between the light source 1 and the array target 7 into M+1 layers for real-time monitoring of environmental parameters between the light source 1 and the array target 7, wherein 0<M≤L / 2.5, and M is an integer, and L is the distance between the light source 1 and the array target 7, in meters. In this embodiment, M is 4. Each group of environmental monitoring sensors includes at least 3 thermometers and hygrometers and 3 anemometers. In this embodiment, each group of environmental monitoring sensors includes 4 thermometers and hygrometers and 4 anemometers. The thermometers and hygrometers and anemometers form an environmental monitoring plane 8. The multiple laser beams emitted by the light source 1 pass through the environmental monitoring plane 8, and the environmental monitoring plane 8 is parallel to the array target 7.

[0094] The image processing unit is electrically connected to the posture solving unit, and is used to correct the original image of the array target 7 to obtain the two-dimensional coordinates of the laser spot mass center, and compensate the two-dimensional coordinates of the laser spot mass center according to the environmental parameters to obtain the two-dimensional coordinates of the laser spot mass center after environmental compensation. The posture solving unit is used to solve the two-dimensional coordinates of the laser spot mass center after environmental compensation to fit the real-time posture of the array target 7.

[0095] The present embodiment also provides an environment-adaptive array target posture measurement method, which is based on the above-mentioned environment-adaptive array target posture measurement system, and uses a laser beam with known spatial posture information to form multiple non-collinear laser spots with each flat target, and then obtains the feature information on each flat target through the camera 2, and obtains the two-dimensional position information of the center of mass of the laser spot on each flat target through the geometric correction method, and calculates the deflection amount of the laser beam using the environmental correction unit 3 built on the laser optical path, and performs position compensation on the two-dimensional position information of the center of mass of the laser spot, and then solves the posture of each flat target by coupling the spatial posture information of the laser beam, and finally combines the quaternion mean method to realize the measurement of the overall posture of the array target 7, and finally realizes non-contact, high-precision measurement.

[0096] Specifically, Figure 1 As shown, taking an array target 7 composed of a first flat target 4, a second flat target 5 and a third flat target 6, each of which has four non-collinear feature points as an example, an environment-adaptive array target posture measurement method provided in this embodiment includes the following steps:

[0097] Step 1: calibrate four non-collinear feature point positions A1, B1, C1 and D1 on the first flat plate target 4, such as Figure 2 As shown, A1 is used as the origin of the coordinate system, and the line connecting A1 and B1 is used as x Axis, x The perpendicular line of the axis at A1 is yAxis, establish a two-dimensional coordinate system, and obtain the two-dimensional coordinates of A1, B1, C1 and D1 ( x A1 , y A1 )、B1( x B1 , y B1 )、C1( x C1 , y C1 ) and D1 ( x D1 , y D1 ); Similarly, the two-dimensional coordinates of the feature points on the second flat plate target 5 and the third flat plate target 6 are obtained.

[0098] Step 2: Turn on the light source 1, emit laser to the array target 7, calibrate all lasers emitted by the light source 1, and obtain the equivalent spatial straight line equation of the laser beam.

[0099] Step 3: The camera 2 collects a two-dimensional image of the array target 7 in the current state and transmits it to the image processing unit. The image processing unit establishes a two-dimensional pixel coordinate system based on the two-dimensional image of the array target 7, such as Figure 3 As shown, the upper left corner of the two-dimensional image of the array target 7 is taken as the coordinate origin. x The axis is parallel to the 2D image plane and points horizontally to the right. y The axis is parallel to the image plane and vertically downward, and a pixel value is used as the unit length of the two-dimensional pixel coordinate system to establish a two-dimensional pixel coordinate system. Then, the centroid pixel coordinates of the feature points A1, B1, C1 and D1 on the first flat target 4 are obtained. a 1( x a1 , y a1 )、 b 1( x b1 , y b1 )、 c 1( x c1 , y c1 )and d 1( x d1 , y d1 ), and the laser spot S 11 , S 12 and S 13 The centroid pixel coordinates S ′ 11 ( x′ 11, y′ 11 )、S ′ 12 ( x′ 12 , y′ 12 ) and S ′ 13 ( x′ 13 , y′ 13 ), similarly, the centroid pixel coordinates of the feature points and the laser spot on the second flat target 5 and the third flat target 6 are obtained.

[0100] Step 4: The image processing unit establishes an image geometry correction model based on the two-dimensional coordinates of the feature points on each flat target obtained in step 1 and the centroid pixel coordinates of the corresponding feature points obtained in step 3; then, based on the image geometry correction model and the centroid pixel coordinates of the laser spot on each flat target obtained in step 3, the two-dimensional coordinates of the centroid of the laser spot in the two-dimensional coordinate system of the corresponding flat target are obtained. Specifically:

[0101] 4.1. Definition: The two-dimensional coordinates of the feature point are ( x ni , y ni , 1) T , and its corresponding centroid pixel coordinates are ( x′ ni , y′ ni , 1) T ;

[0102] Then the geometric transformation relationship of the feature points is:

[0103]

[0104] in, , H n3×3 Indicates n The correction matrix for a flat plate target, n is an integer, and 1≤ n ≤N, h n11 , h n12 , h n21 and h n22 For the n The affine transformation parameters of a flat plate target, h n13 and h n23 For the nThe translation transformation parameters of the flat plate target, h n31 and h n32 Indicates n The transformed edge intersection relationship of the flat plate target, h n33 For h n31 , h n32 The associated scaling factor;

[0105] ( x ni , y ni ) indicates the n Tablet target on the i The two-dimensional coordinates of the feature points, i is an integer, and 1≤ i ≤I;

[0106] ( x′ ni , y′ ni ) indicates the n Tablet target on the i The centroid pixel coordinates of feature points;

[0107] 4.2. Convert the geometric transformation relationship of the feature points to obtain:

[0108]

[0109] 4.3. The two-dimensional coordinates A1 ( x A1 , y A1 )、B1( x B1 , y B1 )、C1( x C1 , y C1 ) and D1 ( x D1 , y D1 ), and the centroid pixel coordinates of the corresponding feature points a 1( x a1 , y a1 )、 b 1( x b1 , y b1 )、c 1( x c1 , y c1 )and d 1( x d1 , y d1 ) is substituted into the formula obtained in step 4.2 to obtain the correction matrix of the first flat plate target 4 Similarly, the correction matrix of the second flat plate target 5 and the third flat plate target 6 is obtained and ;

[0110] 4.4. Using the correction matrix of the first flat target 4, the centroid pixel coordinate S of the laser spot of the first flat target 4 obtained in step 3 is ′ 11 ( x′ 11 , y′ 11 )、S ′ 12 ( x′ 12 , y′ 12 ) and S ′ 13 ( x′ 13 , y′ 13 ) is converted into the two-dimensional coordinates S of the center of mass of the laser spot in the two-dimensional coordinate system of the corresponding flat target 11 ( x 11 , y 11 )、S 12 ( x 12 , y 12 ) and S 13 ( x 13 , y 13 ):

[0111]

[0112] in,( x nj , y nj ) indicates the n Tablet target on the j The two-dimensional coordinates of the center of mass of the laser beam spot, j is an integer, and 1≤ j ≤J;

[0113] ( x′ nj , y′ nj ) indicates the n Tablet target on the j The centroid pixel coordinates of the laser spot;

[0114] Similarly, the centroid pixel coordinates of the laser spots of the second flat target 5 and the third flat target 6 are obtained.

[0115] Step 5: The environmental correction unit 3 obtains the environmental parameters of each layer of the laser light path and sends them to the image processing unit; the image processing unit compensates for the laser deflection caused by environmental factors during the laser transmission process according to the environmental parameters of each layer of the laser light path, and obtains the two-dimensional coordinates of the centroid of the laser spot after environmental compensation. Specifically:

[0116] 5.1. The environmental correction unit 3 obtains the environmental parameters of each layer of the laser light path and sends them to the image processing unit;

[0117] 5.2. The image processing unit uses the environmental parameters of each layer of the laser light path to calculate the atmospheric refractive index of each layer of the laser light path through the following formula:

[0118]

[0119] in, N m Indicates m Layered atmospheric refractive index, m is an integer, and 1≤ m ≤M+1; K is Kelvin temperature, K=T+273.15, T is Celsius temperature, measured by a thermometer and hygrometer; e 0 is the saturated water vapor pressure; p For the m The pressure of the layer is calculated based on the parameters measured by the anemometer; Q is the m The humidity of the layers, measured by a thermohygrometer;

[0120] 5.3. Calculate the laser refraction angle of each layer of the laser optical path using the following formula:

[0121]

[0122] in, θ m Indicates m The refraction angle of each layer, θ 1 is the laser incident angle, N m+1 Indicates m+ 1 layered atmospheric refractive index, θ m+1 Indicates m+ 1 layered laser refraction angle;

[0123] 5.4. Use the laser deflection formula to calculate the laser deflection direction of each layer of the laser optical path;

[0124] 5.5. According to the laser deflection direction of each layer of the laser light path obtained in step 5.4 and the laser refraction angle of each layer of the laser light path obtained in step 5.3, calculate the offset of the laser spot mass center on the flat target, and then obtain the two-dimensional coordinate S of the laser spot mass center after environmental compensation. ′′ nj ( x′′ nj , y′′ nj ).

[0125] Step 6: The posture solving unit calculates the spatial coordinates of the center of mass of each laser spot on each flat target based on the equivalent spatial straight line equation of the laser beam obtained in step 2 and the two-dimensional coordinates of the center of mass of the laser spot after environmental compensation obtained in step 5, and then obtains the current posture of each flat target. The current posture of the flat target is described by the spatial coordinates of the origin of the flat target and the plane normal direction. Specifically:

[0126] 6.1. The two-dimensional coordinates S of the centroid of the laser spot after environmental compensation obtained in step 5 ′′ nj ( x′′ nj , y′′ nj ), calculate the length between the centroids of the laser spots on the same flat target, and then use the principle that the lengths of the same space line segments are equal, and according to the equivalent space straight line equation of the laser beam obtained in step 2, calculate the spatial coordinates of the centroid of each laser spot on each flat target;

[0127] 6.2. Definition: Any point on the first flat target 4 is the origin of the first flat target 4;

[0128] 6.3. Based on the two-dimensional coordinates of the centroid of the laser spot after environmental compensation obtained in step 5, calculate the length between the centroid of each laser spot and the origin of the first flat target 4, and then use the principle that the lengths of the same spatial line segments are equal to obtain the spatial coordinates of the origin of the first flat target 4 based on the spatial coordinates of the centroid of the laser spot on the first flat target 4;

[0129] 6.4. Based on the spatial coordinates of the origin of the first flat target 4 and the spatial coordinates of the centroid of the laser spot of the flat target, the plane normal direction of the origin of the first flat target 4 is calculated, and the spatial coordinates of the origin of the first flat target 4 obtained in step 6.3 together constitute the current posture of the first flat target 4;

[0130] 6.5. According to the method of steps 6.2 to 6.4, the current positions of the second flat plate target 5 and the third flat plate target 6 are obtained.

[0131] Step 7: Change the position and posture of the array target 7. According to the method of steps 3 to 6, obtain the position and posture of each flat plate target after the position and posture of the array target 7 is changed.

[0132] Step 8: The posture solving unit calculates the translation parameters and rotation parameters of the overall posture of the array target 7 according to the current posture of each flat target and the posture of each flat target after the posture of the array target 7 is changed, thereby obtaining the real-time posture of the array target 7. Specifically:

[0133] 8.1. According to the current posture of each flat target and the posture of each flat target after the posture of array target 7 is changed, the translation parameter and rotation parameter of each flat target are obtained by using the three-dimensional coordinate transformation of the seven-parameter Bursa model space;

[0134] 8.2. According to the translation parameters of each flat target, the translation parameters of the overall position of the array target 7 are calculated using the following formula:

[0135]

[0136] Wherein, T is the translation parameter of the overall position of the array target 7, For the n Translation parameters of a flat plate target;

[0137] 8.3. According to the rotation parameters of each flat plate target, construct the rotation quaternion of each flat plate target:

[0138]

[0139] in, Indicates n The rotation quaternion of a flat target, [ l nx , l ny , l nz ] = L n , L n For the n The rotation parameters of a flat plate target, l nx , l ny , l nz Respectively represent n The rotation parameters of the flat plate target in the space coordinate system x axis, y axis,z The coordinates of the axes;

[0140] 8.4. The rotation quaternions of each flat target are combined into an N×4 matrix Q. The covariance matrix C of the matrix Q is calculated by the following formula:

[0141]

[0142] 8.5. Calculate the eigenvector corresponding to the maximum eigenvalue of the covariance matrix C, and then normalize it to obtain the quaternion eigenvector;

[0143] 8.6. Convert the quaternion eigenvector into a rotation matrix to obtain the rotation parameters of the overall position of the array target, which together with the translation parameters of the overall position of the array target 7 obtained in step 8.2 constitute the real-time position of the array target 7.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. An environment-adaptive array target position and posture measurement system, wherein the array target (7) is composed of N flat targets, each of which has I non-collinear feature points, wherein: N≥2, I≥4, and N and I are both integers; characterized in that: it comprises a light source (1), a camera (2), an environment correction unit (3), an image processing unit and a posture solving unit; The light source (1) and the camera (2) are located on the same side of the array target (7), and the light source (1) is used to emit multiple laser beams to the array target (7), wherein a single flat target receives J laser beams, and the coverage range of the J laser beams is greater than the range of movement of the single flat target, wherein J ≥ 3 and is an integer; The camera (2) is electrically connected to the image processing unit, and is used to detect image information of the array target (7) and the laser spot, and transmit a two-dimensional image of the array target (7) to the image processing unit; The environmental correction unit (3) comprises M groups of environmental monitoring sensors arranged in sequence along the laser light path and electrically connected to the image processing unit, the M groups of environmental monitoring sensors dividing the laser light path between the light source (1) and the array target (7) into M+1 layers, and used for real-time monitoring of environmental parameters between the light source (1) and the array target (7), wherein M is an integer greater than 0; Each group of the environmental monitoring sensors includes at least three thermometers and three anemometers; the thermometers and anemometers form an environmental monitoring plane (8); the multiple laser beams emitted by the light source (1) pass through the environmental monitoring plane (8), and the environmental monitoring plane (8) is parallel to the array target (7); The image processing unit is electrically connected to the posture solving unit and is used to correct the two-dimensional image of the array target (7) to obtain the two-dimensional coordinates of the center of mass of the laser spot, and to compensate the two-dimensional coordinates of the center of mass of the laser spot according to the environmental parameters to obtain the two-dimensional coordinates of the center of mass of the laser spot after environmental compensation; The posture solving unit is used to solve the two-dimensional coordinates of the centroid of the laser spot after environmental compensation, and then fit the real-time posture of the array target (7).

2. The environment-adaptive array target position and posture measurement system according to claim 1, characterized in that: 4≤I≤6, 3≤J≤6, 0<M≤L / 2.5, where L is the distance between the light source (1) and the array target (7), in meters.

3. The environment-adaptive array target position and posture measurement system according to claim 2, characterized in that: The field of view of the camera (2) covers at least a single flat target.

4. An environment-adaptive array target position and posture measurement method, based on an environment-adaptive array target position and posture measurement system according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: calibrate the position of one non-collinear feature point on each flat target, establish a two-dimensional coordinate system based on the flat target, and obtain the two-dimensional coordinates of the feature point on each flat target; Step 2, turning on the light source (1), emitting laser light to the array target (7), calibrating all laser beams emitted by the light source (1), and obtaining an equivalent spatial straight line equation of the laser beam; Step 3, the camera (2) collects a two-dimensional image of the array target (7) in the current state and transmits it to the image processing unit; the image processing unit establishes a two-dimensional pixel coordinate system based on the two-dimensional image of the array target (7), and then obtains the pixel coordinates of the centroid of the feature points and the laser spot on each flat target; Step 4: The image processing unit establishes an image geometry correction model based on the two-dimensional coordinates of the feature points on each flat target obtained in step 1 and the centroid pixel coordinates of the corresponding feature points obtained in step 3; then, according to the image geometry correction model and the centroid pixel coordinates of the laser spot on each flat target obtained in step 3, the two-dimensional coordinates of the centroid of the laser spot in the two-dimensional coordinate system of the corresponding flat target are obtained; Step 5, the environmental correction unit (3) obtains the environmental parameters of each layer of the laser light path and sends them to the image processing unit; the image processing unit compensates for the laser deflection caused by environmental factors during the laser transmission process according to the environmental parameters of each layer of the laser light path, and obtains the two-dimensional coordinates of the centroid of the laser spot after environmental compensation; Step 6, the posture solving unit calculates the spatial coordinates of the center of mass of each laser spot on each flat target based on the equivalent spatial straight line equation of the laser beam obtained in step 2 and the two-dimensional coordinates of the center of mass of the laser spot after environment compensation obtained in step 5, and then obtains the current posture of each flat target; Step 7, changing the position and posture of the array target (7), and obtaining the position and posture of each flat plate target after the position and posture of the array target (7) is changed according to the method of steps 3 to 6; Step 8: The posture solving unit calculates the translation parameters and rotation parameters of the overall posture of the array target (7) according to the current posture of each flat target and the posture of each flat target after the posture of the array target (7) is changed, thereby obtaining the real-time posture of the array target (7).

5. The method for measuring the position and posture of an array target in an environment-adaptive manner according to claim 4, characterized in that: Step 4 is as follows: 4.

1. Definition: The two-dimensional coordinates of the feature point are ( x ni , y ni , 1) T , and its corresponding centroid pixel coordinates are ( x′ ni , y′ ni , 1) T ; Then the geometric transformation relationship of the feature points is: ； in, , H n3×3 Indicates n The correction matrix for a flat plate target, n is an integer, and 1≤ n ≤ N, h n11 , h n12 , h n21 and h n22 For the n The affine transformation parameters of a flat plate target, h n13 and h n23 For the n The translation transformation parameters of the flat plate target, h n31 and h n32 Indicates n The transformed edge intersection relationship of the flat plate target, h n33 For h n31 , h n32 The associated scaling factor; ( x ni , y ni ) indicates the n Tablet target on the i The two-dimensional coordinates of the feature points, i is an integer, and 1≤ i ≤I; ( x′ ni , y′ ni ) indicates the n Tablet target on the i The centroid pixel coordinates of feature points; 4.

2. Convert the geometric transformation relationship of the feature points to obtain: ； 4.

3. Substitute the two-dimensional coordinates of the feature points on each flat target obtained in step 1 and the centroid pixel coordinates of the corresponding feature points obtained in step 3 into the formula obtained in step 4.2 to calculate the correction matrix of each flat target; 4.

4. Using the correction matrix of each flat target, convert the pixel coordinates of the centroid of the laser spot on each flat target obtained in step 3 into the two-dimensional coordinates of the centroid of the laser spot in the two-dimensional coordinate system of the corresponding flat target: ； in,( x nj , y nj ) indicates the n Tablet target on the j The two-dimensional coordinates of the center of mass of the laser beam spot, j is an integer, and 1≤ j ≤J; ( x′ nj , y′ nj ) indicates the n Tablet target on the j The pixel coordinates of the centroid of the laser spot.

6. The method for measuring the position and posture of an array target in an environment-adaptive manner according to claim 5, characterized in that: Step 5 is as follows: 5.

1. The environmental correction unit (3) obtains the environmental parameters of each layer of the laser light path and sends them to the image processing unit; 5.

2. The image processing unit uses the environmental parameters of each layer of the laser light path to calculate the atmospheric refractive index of each layer of the laser light path through the following formula: ； in, N m Indicates m Layered atmospheric refractive index, m is an integer, and 1≤ m ≤M+1; K is Kelvin temperature, K=T+273.15, T is Celsius temperature, measured by a thermometer and hygrometer; e 0 is the saturated water vapor pressure; p For the m The pressure of the layers is calculated based on the parameters measured by the anemometer; Q is the m The humidity of the layers, measured by a thermohygrometer; 5.

3. Calculate the laser refraction angle of each layer of the laser optical path using the following formula: ； in, θ m Indicates m The laser refraction angle of each layer, m =1, θ m is the laser incident angle, N m+1 Indicates m+ 1 layered atmospheric refractive index, θ m+1 Indicates m+ 1 layered laser refraction angle; 5.

4. Use the laser deflection formula to calculate the laser deflection direction of each layer of the laser optical path; 5.

5. According to the laser deflection direction of each layer of the laser light path obtained in step 5.4 and the laser refraction angle of each layer of the laser light path obtained in step 5.3, calculate the offset of the laser spot centroid on the corresponding flat target, and then obtain the two-dimensional coordinates of the laser spot centroid after environmental compensation.

7. The method for measuring the position and posture of an array target in an environment-adaptive manner according to claim 6, characterized in that: Step 6 is as follows: 6.

1. Based on the two-dimensional coordinates of the centroids of the laser spots after environmental compensation obtained in step 5, calculate the lengths between the centroids of the laser spots on the same flat target. Then, based on the principle that the lengths of the same spatial line segments are equal, calculate the spatial coordinates of the centroids of each laser spot on each flat target according to the equivalent spatial straight line equation of the laser beam obtained in step 2. 6.

2. Definition: Any point on a flat plate target is the origin of the flat plate target; 6.

3. Based on the two-dimensional coordinates of the centroid of the laser spot after environmental compensation obtained in step 5, calculate the length between the centroid of each laser spot on each flat target and the origin, and then use the principle that the lengths of the same spatial line segments are equal to obtain the spatial coordinates of the origin of each flat target based on the spatial coordinates of the centroid of each laser spot on the flat target; 6.

4. Based on the spatial coordinates of the origin of each flat target and the spatial coordinates of the centroid of each laser spot on the flat target, calculate the plane normal direction of the origin of each flat target, and together with the spatial coordinates of the origin of each flat target obtained in step 6.3, constitute the current posture of each flat target.

8. The method for measuring the position and posture of an array target in an environment-adaptive manner according to claim 7, characterized in that: Step 8 is as follows: 8.

1. Based on the current posture of each flat target and the posture of each flat target after the posture of the array target (7) is changed, the translation parameter and rotation parameter of each flat target are obtained by using the seven-parameter Bursa model space three-dimensional coordinate transformation; 8.

2. Based on the translation parameters of each flat target, the translation parameters of the overall position of the array target (7) are calculated using the following formula: ； Among them, T is the translation parameter of the overall position of the array target, For the n Translation parameters of a flat plate target; 8.

3. According to the rotation parameters of each flat plate target, construct the rotation quaternion of each flat plate target: ； in, Indicates n The rotation quaternion of a flat target, [ l nx , l ny , l nz ] = L n , L n For the n The rotation parameters of a flat plate target, l nx , l ny , l nz Respectively represent n The rotation parameters of the flat plate target in the space coordinate system x axis, y axis, z The coordinates of the axes; 8.

4. The rotation quaternions of each flat target are combined into an N×4 matrix Q. The covariance matrix C of the matrix Q is calculated by the following formula: ； 8.

5. Calculate the eigenvector corresponding to the maximum eigenvalue of the covariance matrix C, and then normalize it to obtain the quaternion eigenvector; 8.

6. Convert the quaternion eigenvector into a rotation matrix to obtain the rotation parameters of the overall posture of the array target (7), which together with the translation parameters of the overall posture of the array target (7) obtained in step 8.2 constitute the real-time posture of the array target (7).

9. An environment-adaptive array target position and posture measurement method according to any one of claims 4 to 8, characterized in that: In step 1, the specific method of establishing the two-dimensional coordinate system is: Take any feature point on the flat target as the coordinate origin, and the line connecting the coordinate origin and another feature point as x Axis, x The perpendicular line of the axis at the origin of the coordinate system is y Axis, establish a two-dimensional coordinate system.

10. The method for measuring array target pose in an environment-adaptive manner according to claim 9, characterized in that: In step 3, the specific method of establishing the two-dimensional pixel coordinate system is: Take the upper left corner of the two-dimensional image of the array target (7) as the coordinate origin, so x The axis is parallel to the 2D image plane and points horizontally to the right. y The axis is parallel to the 2D image plane and runs vertically downward, with one pixel value as the unit length.

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