CN116184654A - Coordinate system construction method, prism scanner multi-target detection scanning method and system - Google Patents
Coordinate system construction method, prism scanner multi-target detection scanning method and system Download PDFInfo
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Abstract
The invention relates to a coordinate system construction method, a multi-target detection scanning method and a multi-target detection scanning system for a prism scanner. Compared with the prior art, the method has the advantages that a multiple prism coordinate system is built, the prism movement angles of the cascaded prisms are assigned to coordinate system axes with the same dimension, one coordinate point represents the prism state at a certain moment, and the distance between the coordinate points represents the prism movement condition in a period of time; the method has the advantages that the complete description of the motion state of the prism is realized, the definition and the use difficulty of a coordinate system are reduced, the space target point planning problem is converted into prism motion path planning for directly controlling laser beams, the speed is high, the efficiency is high, the path obtained by planning is used for realizing that the operation distance of the prism is shortest or the speed is fastest as a scanning target, the overall energy consumption of a scanner is reduced, the operation smoothness of the prism is improved, meanwhile, the motor eccentric wear can be avoided by the same-direction principle, and theoretical basis and application foundation are provided for scanning and tracking of a large-range, long-distance and unordered multiple targets.
Description
Technical Field
The present invention relates to the technical field of prism scanners, and in particular, to a coordinate system construction method, a multi-target detection scanning method and a multi-target detection scanning system for a prism scanner.
Background
The active photoelectric identification scanning system is characterized in that the core is an optical axis adjustment technology, namely, the pointing end point of a visual sensor is an identification target or an interested target is always positioned in the center of a field of view by continuously adjusting the pointing of a visual axis. Researchers acquire multi-view image information by changing the pose of a vision sensor or changing the imaging view axis angle. The proposal for changing the imaging visual axis angle of the camera can be divided into three types, namely a multi-axis holder (Yang Liang, zhou Yong, liuliu), a PTZ camera-based moving object tracking control [ J ]. Weapon automation, 2014, (3): 65-68.), a reflective optical system (Shanghai technical and physical research institute of China academy of sciences; a quick mirror scanning tracking system and method for the field of aerospace imaging: CN201410020863.5[ P ]. 2014-06-25.), and a refractive optical system (Cui X.Y., zhao Y., lim K.B., et al. Selective projection model for prism-based stereoscopic Express,2015, 23:27542-27557.63). The refraction type optical variable visual axis imaging scheme has the characteristics of quick response, high precision, compact structure, good robustness and the like, and the relative pose of the vision sensor is fixed, and the imaging visual axis is changed by utilizing the deflection or the rotary motion of the front wedge-shaped optical prism. Prism-based lidar is currently used in the fields of laser communication, radar, infrared countermeasure, and the like.
When the prism scanner works, the rotation angle value and the rotation speed of each prism determine the pointing direction and the movement state of the adjustable optical axis. Thus, characterizing the state of each prism in a prism scanner is a necessary condition for active visual identification and photoelectric tracking. However, the common cartesian rectangular coordinate system, the planar polar coordinate system, the cylindrical coordinate system, the spherical coordinate system, and the like cannot intuitively and simultaneously express the angular positions of the plurality of prisms at the time t and the position change from the time t to the time t+1. Furthermore, the spatial optical axis pointing vector of the prism scanner and the angular value of each prism have high nonlinearity and strong coupling, which means that the spatial pointing scan plan under a conventional rectangular coordinate system is not the optimal solution for the prism motion and the two do not correspond linearly.
Due to the application limitation of the coordinate system, the prism scanner cannot completely express the motion path of the prism group during multi-target detection scanning, and the optimal scanning path planning is difficult to realize. A new coordinate system is needed to describe the motion of the cascaded prism set, characterize its relationship with the viewing axis adjustment, and apply to the optimal scan path planning for multi-target scout scans.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a coordinate system construction method, a multi-target detection scanning method and a multi-target detection scanning system for a prism scanner, wherein prism motion values are given to Cartesian coordinate axes to represent the motion state of the prism. In the coordinate system, the running path of the prism can be directly planned, and the unordered multi-target scanning with high speed and low energy consumption can be realized.
The aim of the invention can be achieved by the following technical scheme:
a coordinate system construction method is applied to a cascading prism set, and comprises the following steps:
establishing an n-dimensional coordinate system, wherein n is equal to the number of prisms in the cascade prism group, and defining points under the coordinate system: each coordinate axis corresponds to the independent movement angle of different prisms, and one coordinate axis point in the coordinate system represents the prism state at a certain moment;
defining the inter-point distance in the coordinate system: the distance between two points in the coordinate system is expressed as:
in the shortest distance mode:
wherein ,θia Representing the projection value of point a on coordinate axis i, θ ib Representing the projection of point b on coordinate axis i,
representing all the coordinate axis distances between the points a and b, which are mathematically defined as Manhattan distances, the points a and b representing the time t a Next time t b Prism state d ml Representing the movement of the prism at one object point in shortest distance modeTotal distance;
since the prism rotation is performed simultaneously, in the fastest distance mode:
defining the inter-point road difference under a coordinate system:
wherein ,
representing the maximum road difference between the point a and the point b; d (D) d The maximum total road difference of the prism at the l target points is indicated.
Further, for ease of calculation, reference is made to the maximum road-to-difference ratio:
I d representing the maximum road-to-difference ratio between the i target points.
A multi-target detection scanning method of a prism scanner, wherein the prism scanner comprises a laser radar emitter, a vision guiding range finding camera, a cascading prism group and a support control system, the vision guiding range finding camera is arranged on a paraxial of the laser radar emitter, and the cascading prism group is coaxially arranged in front of the laser radar emitter in a plane parallel manner, and the scanning method comprises the following steps:
s1, calibrating camera internal parameters, obtaining an imaging model of a vision-guided ranging camera, and establishing a conversion relation between a world coordinate system and a pixel coordinate system; shooting a plurality of long-distance targets by using a vision-guided ranging camera, and identifying and marking the targets in the acquired images to obtain a target point map in a pixel coordinate system;
s2, establishing a multiple prism coordinate system by using the coordinate system construction method, wherein the movement angle of the prism is a function of time t;
s3, establishing a reverse resolving relation between an optical axis pointing angle and a motion value of each prism, and realizing conversion from a pixel coordinate system to a multiple prism coordinate system;
s4, in a multiple prism coordinate system, abstracting the prism scanner motion planning into a multipoint tourist problem, and planning multiple prism motion paths;
s5, controlling the prism scanner to sequentially complete scanning of each target point according to the planned multiple prism motion paths.
Further, the method further comprises the following steps:
s6, calculating emergent laser directions according to the planned multiple prism motion paths by using an iterative vector method, forming an estimated target point map in a world coordinate system, comparing and feeding back the estimated target point map with the target point map obtained by the actual scanning directions in the step S5, and correcting the prism scanner motion.
Further, in step S1, the camera internal parameters are calibrated using Zhang Zhengyou method.
Further, in step S4, the shortest path or the fastest path or a weighted combination of the shortest path and the fastest path is used as an optimization target.
Further, in step S4, the cascaded prism set generates 2n motion modes Mode, where n is the number of prisms.
Further, in step S4, for the obtained multiple prism motion paths, a prism motion path feature map is drawn according to the same direction operation rule, and the shortest distance, the fastest distance and the maximum road difference ratio are used as the path judgment criteria.
A prism scanner multi-target detection scanning system, the prism scanner includes laser radar transmitter, vision guide range finding camera, cascade prism group and support control system, vision guide range finding camera sets up at laser radar transmitter paraxial, cascade prism group is coaxial and the plane is parallel to be arranged in laser radar transmitter directly in front, scanning system includes:
the pixel coordinate system module is used for calibrating the internal parameters of the camera, obtaining an imaging model of the vision-guided ranging camera, and establishing a conversion relation between a world coordinate system and the pixel coordinate system; shooting a plurality of long-distance targets by using a vision-guided ranging camera, and identifying and marking the targets in the acquired images to obtain a target point map in a pixel coordinate system;
the multiple prism coordinate system module is used for establishing a multiple prism coordinate system by using the coordinate system construction method, and the movement angle of the prism is a function of time t;
the coordinate conversion module is used for establishing a reverse resolving relation between the optical axis pointing angle and the motion value of each prism and realizing conversion from a pixel coordinate system to a multiple prism coordinate system;
the planning module is used for abstracting the motion planning of the prism scanner into a multi-point travel business problem in a multi-prism coordinate system and planning a multi-prism motion path;
and the scanning control module is used for controlling the prism scanner to sequentially complete the scanning of each target point according to the planned multiple prism movement path.
Further, the method further comprises the following steps:
the feedback correction module is used for calculating emergent laser directions by using an iterative vector method according to the planned multiple prism motion paths, forming an estimated target point map in a world coordinate system, comparing and feeding back the estimated target point map with a target point map obtained by actual scanning directions in the scanning control module, and correcting the prism scanner motion of the scanning control module.
Compared with the prior art, the invention has the following beneficial effects:
(1) Assigning each prism movement angle of the cascade prisms to coordinate system axes with the same dimension, wherein one coordinate point represents the prism state at a certain moment, and the distance between the coordinate points represents the prism movement condition in a period of time; the method not only realizes the complete description of the motion state of the prism, but also adopts the characteristics of a classical rectangular coordinate system, the motion condition of the prism can be defined by related mathematical distances, and the definition and use difficulty of the coordinate system are greatly reduced.
(2) Based on a multiple prism coordinate system, the prism reverse resolving is skillfully utilized, the directional vector of the spatial optical axis is put into the multiple prism coordinate system, the spatial target point planning problem is converted into prism motion path planning for directly controlling laser beams, the spatial target point planning is decoupled from the prism motion planning, the speed is high, the efficiency is high, the prism emergent directional speed reduction ratio is large, and the directional precision is high.
(3) The path obtained by planning is taken as a scanning target with the shortest prism running distance or the fastest speed, so that the overall energy consumption of the scanner is reduced, the running waiting time of different prisms is reduced, the running smoothness of the prisms is improved, meanwhile, the motor eccentric wear can be avoided by the same-direction principle, and a theoretical basis and an application foundation are provided for scanning and tracking of multiple targets in a large range, long distance and disorder.
Drawings
FIG. 1 is a directional planning process for a spatially unordered multi-target by a prism scanner;
FIG. 2 is a correspondence of a cascading prism set to a multiple prism coordinate system;
FIG. 3 is a transformation relationship between a camera pixel coordinate system and a multiple prism coordinate system using a rotating biprism scanner as an example; wherein (a) and (b) are the target point maps in the pixel coordinate system and the prism coordinate system, respectively;
FIG. 4 is a diagram of the path characteristics of two scan targets, four modes of motion in a multiple prism coordinate system, using a rotating biprism scanner as an example; wherein (a) is shortest path planning and (b) is fastest path planning;
FIG. 5 is a comparison of path planning results using a multiple prism coordinate system with a conventional coordinate system using a rotating biprism scanner as an example;
fig. 6 is a flowchart of a specific application of the rotating prism coordinate system according to the present invention.
Reference numerals: 1-a cascade prism group; 2-a lidar transmitter; 3-a multiple prism coordinate system; 4-a vision-guided range camera; 5-camera pixel coordinate system; 6-prism scan field of view coordinate system (world coordinate system); 7-scanning the target.
Detailed Description
The invention will now be described in detail with reference to the drawings and specific examples. The present embodiment is implemented on the premise of the technical scheme of the present invention, and a detailed implementation manner and a specific operation process are given, but the protection scope of the present invention is not limited to the following examples.
Example 1:
a coordinate system construction method is applied to a cascading prism set, and comprises the following steps:
(1) Establishing an n-dimensional coordinate system, wherein n is equal to the number of prisms in the cascade prism group, and defining points under the coordinate system: each coordinate axis corresponds to the independent movement angle of different prisms, one coordinate axis point in the coordinate system represents the prism state at a certain moment, the prism movement angles of n cascaded prisms are assigned to the coordinate system with the same dimension n, the direction of the whole prism group can be decomposed into the movement of each prism, and the movement angle of each prism is a function of time t; the n-dimensional coordinate system is utilized to disperse the movement of the prism group into a plurality of points according to time within a period of time, each point can represent the pointing state of the prism group at a certain time, and the coordinates of the points on all coordinate axes in the coordinate system represent the movement angles of all prisms in the prism group.
(2) Defining the inter-point distance in the coordinate system:
in the shortest distance mode:
the movement path of the prism group is the sum of the movement paths of the prisms, so that the distance between two points is the distance between the prism group and the prism group, the distance is expressed as algebraic sum of projection differences of the two points on a coordinate axis, the mathematical expression is Manhattan distance, and the distance between the two points in a coordinate system is expressed as:
wherein ,θia Representing the projection value of point a on coordinate axis i, θ ib Representing the projection of point b on coordinate axis i,
representing the distance between points a and b, mathematically defined as Manhattan distance, points a and b representing the instant t a Next time t b Prism state of (2);
thus, for a scan of l unordered target points in space, the total motion path of the prism group for l state switches is as follows:
D ml representing the total movement distance of the prism when the three unordered target points are in the shortest distance mode;
in the fastest distance mode:
because the different prisms in the prism group move relatively independently, namely a plurality of prisms in the prism group can perform angle movement in parallel, the movement time of the prism group in the two-state switching process only depends on the maximum value of the projection difference of two state points on a coordinate axis, and the maximum value is expressed as a car-to-snow distance mathematically, so that the total movement path of the prism scanning in the fastest distance mode is as follows:
(3) Defining the inter-point road difference under a coordinate system:
between the two state points, the maximum movement distance of the prism group on the coordinate axis is the vehicle-to-snow distance, and a relative shortest distance min exists correspondingly 1≤i≤n |θ ia -θ ib I, thereby defining the maximum road difference of the prism group
wherein ,
representing the road difference between the point a and the point b;
similarly, for l unordered target points, define the maximum total road difference of the prism:
wherein ,Dd Representing the maximum total road difference of the l out-of-order target point prisms.
Taking into account the maximum total road difference D d Is complex, and refers to the maximum road-to-difference ratio to simplify the calculation:
I d representing the maximum road difference ratio between the l target points。
As shown in fig. 1, the prism scanner includes a lidar transmitter, a vision-guided range camera, a cascading prism set, and a support control system, which may be used to scan path planning for unordered multi-targets:
the laser radar transmitter is used for transmitting laser, directing the laser to the targets in the space after being refracted by the prism group, and sequentially completing the scanning of each target in a field-of-view coordinate system (world coordinate system) of the prism scanner.
The vision guiding range finding camera is arranged on a paraxial of the laser radar transmitter, adopts a high-frame frequency CCD camera and is used for shooting a plurality of discrete unordered targets in world space and imaging in a camera pixel coordinate system. The internal parameters of the camera, such as the field angle, focal length, resolution, etc., and the external position parameters (rotation matrix and translation matrix) of the camera and the optical element are synchronously adjusted according to the specific application scene change.
The cascade prism group is coaxial and the plane is parallel to be arranged right in front of the laser radar transmitter, and the cascade prism group is used for adjusting laser pointing direction and is coaxial and the plane is parallel to be arranged right in front of the laser radar transmitter. The cascade prism group is formed by connecting a plurality of coaxial wedge prisms in series, and the movement form comprises independent rotation or independent deflection. The specific optical parameters and arrangement of the optical elements are matched and adjusted according to the requirements of the field of view range and the like.
The support control system includes a series of support, adjustment, transmission, drive, and control components. The driving part can adopt modes of torque motor direct drive or gear transmission, synchronous belt transmission, worm and gear transmission and the like.
The application provides a multi-target detection scanning method of a prism scanner, which totally relates to three main coordinate systems: the scanning method comprises the following steps of:
s1, constructing a camera imaging model: calibrating camera internal parameters by using a Zhang Zhengyou method, obtaining an imaging model of a vision-guided ranging camera, and establishing a conversion relation between a world coordinate system and a camera pixel coordinate system;
forming a pixel target point map: shooting a plurality of long-distance targets by using a vision-guided ranging camera, identifying and marking characteristic parts in the images by adopting a vision identification algorithm according to the images acquired by the camera, and abstracting and simplifying the images into a target point map in a pixel coordinate system;
s2, establishing a multiple prism coordinate system: establishing a multiple prism coordinate system by using the coordinate system construction method, wherein the movement angle of the prism is a function of time t;
as shown in fig. 2, the prism scanner is formed by connecting i coaxial prisms in series, wherein the prism movement modes comprise rotation and deflection, and the movement angle is θ. The multiple prism coordinate system gives the prism movement angle theta amplitude of i cascaded prisms to rectangular coordinate axes with the same dimension n, wherein each coordinate axis n=i (i epsilon Z+) represents the independent movement state of the corresponding prism, and the movement angle is a function theta of time t i (t)。
S3, constructing a prism motion inverse solution model: establishing a reverse resolving relation between an optical axis pointing angle and a motion value of each prism, and realizing conversion from a pixel coordinate system to a multiple prism coordinate system, thereby realizing coordinate conversion among a world coordinate system (a prism scanner field coordinate system), a camera pixel coordinate system and the multiple prism coordinate system; the inverse solution may be a two-step method, a table look-up method, and an iterative method according to the accuracy requirement, which are understood by those skilled in the art and will not be described herein.
As shown in fig. 3, the directional vector of the spatial optical axis can be put into the rotating prism coordinate system by inverse solution of the biprism, and one coordinate axis point represents the prism state at a certain moment. The spatial target point planning problem is converted into a prism motion planning problem for controlling the beam pointing. Because the cascade prism reverse solution belongs to nonlinear mapping, a plurality of groups of equivalent solutions exist, the cascade prism reverse solution is reflected in a multiple prism coordinate system, more than one group of target points exist on a target solution point map, and point elimination and selection are needed during planning. The coordinate axes of the multiple prism coordinate systems are mutually perpendicular, the distance formula and definition in the classical rectangular coordinate system can be used, the prism motion planning problem can be abstracted into a multipoint tourist problem, and the planning selection is performed by combining a mature algorithm with a tabu list.
S4, in a multiple prism coordinate system, abstracting the prism scanner motion planning into a multipoint tourist problem, and planning multiple prism motion paths; in short, a certain state of the cascaded prism group corresponds to an adjustment scheme of laser pointing, and a reasonable design scheme is required to complete scanning of all target points in the face of a plurality of unordered targets, so that the planned multiple prism movement path is a set of data containing a plurality of state points, each state point corresponds to a movement state (movement angle of each prism) of the cascaded prism group, and the prism scanner sequentially adjusts the prism angles of each prism according to the planned multiple prism movement path, thereby completing scanning. For the problem of multi-point traveller, the existing algorithm calculation such as ant colony algorithm, genetic algorithm, backtracking method, greedy method, branch limit method and the like can be utilized.
For the service life of the whole machine, the shortest path loss is minimum; but for search efficiency, the fastest path can complete a given target scan in the shortest time. Two different optimization targets exist, and in the actual planning process, one of the targets is selected according to the requirements or the two targets are combined according to a weighting mode.
In order to ensure stable driving and transmission of the prism, the prism keeps continuous and same-direction operation. The cascaded prisms generate a total of 2n motion modes Mode, where n is the number of prisms. The operation modes of the rotating biprism are, for example: all forward rotation; full inversion; prism 1 rotates forward and prism 2 rotates backward; prism 1 rotates in reverse and prism 2 rotates in forward.
And planning an optimal path according to different scanning targets, drawing a prism motion path characteristic diagram according to a homodromous operation rule, and taking the shortest distance, the fastest distance and the maximum path difference ratio as main basis and judgment standard of the whole machine target scanning path planning. In other embodiments, the evaluation criteria may be flexibly adjusted in combination with the optimization objectives.
S5, controlling the prism scanner to sequentially complete scanning of each target point according to the planned multiple prism motion paths.
S6, calculating emergent laser directions according to the planned multiple prism motion paths by using an iterative vector method, forming an estimated target point map in a world coordinate system, comparing and feeding back the estimated target point map with the target point map obtained by the actual scanning directions in the step S5, and correcting the prism scanner motion.
The application also provides a prism scanner multi-target detection scanning system, and the prism scanner includes laser radar transmitter, vision guide range finding camera, cascade prism group and support control system, and vision guide range finding camera sets up at laser radar transmitter paraxial, and cascade prism group is coaxial and the plane parallel arranges in laser radar transmitter directly in the place ahead, and scanning system includes:
the pixel coordinate system module is used for calibrating the internal parameters of the camera, obtaining an imaging model of the vision-guided ranging camera, and establishing a conversion relation between a world coordinate system and the pixel coordinate system; shooting a plurality of long-distance targets by using a vision-guided ranging camera, and identifying and marking the targets in the acquired images to obtain a target point map in a pixel coordinate system;
the multiple prism coordinate system module is used for establishing a multiple prism coordinate system by using the coordinate system construction method, and the movement angle of the prism is a function of time t;
the coordinate conversion module is used for establishing a reverse resolving relation between the optical axis pointing angle and the motion value of each prism and realizing conversion from a pixel coordinate system to a multiple prism coordinate system;
the planning module is used for abstracting the motion planning of the prism scanner into a multi-point travel business problem in a multi-prism coordinate system and planning a multi-prism motion path;
and the scanning control module is used for controlling the prism scanner to sequentially complete the scanning of each target point according to the planned multiple prism movement path.
The feedback correction module is used for calculating emergent laser directions by using an iterative vector method according to the planned multiple prism motion paths, forming an estimated target point map in a world coordinate system, comparing and feeding back the estimated target point map with a target point map obtained by actual scanning directions in the scanning control module, and correcting the prism scanner motion of the scanning control module.
The working content of each module in the scanning system is the same as that of the scanning method, and is not described herein.
According to the invention, the prism rotation angles of i cascaded prisms are assigned to a rectangular coordinate system axis with the same dimension n, n=i (i epsilon Z+), and one point represents the prism state at a certain moment; the prism reverse solution is skillfully utilized, and the directional vector of the space optical axis is put into a multiple prism coordinate system, so that the motion planning of the prism state point can be directly carried out; under the multiple prism coordinate system, the motion condition of the prism scanner can be defined by the existing distance in the classical rectangular coordinate system, the planning problem can be abstracted into a travel business problem, and the calculation is performed by using the existing algorithm.
The application will be described with reference to a prism scanner comprising a rotating biprism, the application flow being as shown in fig. 6:
s1, constructing a camera imaging model: calibrating a camera internal reference by using a Zhang Zhengyou method, obtaining an imaging model of an industrial CCD camera, and establishing a conversion relation between a world coordinate system and a camera pixel coordinate system;
forming a pixel target point map: and shooting the remote multi-target by using a CCD camera, identifying and marking 16 characteristic targets (namely identifying the object to be searched) in the images acquired by the camera by adopting a visual identification algorithm, abstracting and simplifying the map to be a target point map of 16 points in a pixel coordinate system, and drawing a map plane in the pixel coordinate system.
S2, establishing a multiple prism coordinate system: a classical two-dimensional coordinate system is established, the coordinate axes are mutually perpendicular, the rotation range of the prism 1 corresponds to the X axis, and the rotation range of the prism 2 corresponds to the Y axis. The prisms are independently rotated about a common axis. Let the prism rotate positive in the counter-clockwise direction and negative in the clockwise direction. In the initial state, the thin end of the prism points to the X-axis forward direction of the world coordinate system, and the rotation angle is a function theta of time t i (t)。
S21, defining points under a multiple prism coordinate system: each coordinate axis corresponds to the independent movement angle of different prisms, and one coordinate axis point in the coordinate system represents the prism state at a certain moment.
S22, defining the inter-point distance under a multiple prism coordinate system: the total motion distance of the prism is the algebraic sum of projection of all target state points on a coordinate axis, and is expressed as Manhattan distance in a mathematical way:
because the movement of different prisms is relatively independent, the movement time of the prism only depends on the maximum projection distance of the state point on the coordinate axis, and is expressed as the vehicle-to-snow distance in a mathematical way:
s23, defining the inter-point path difference under the coordinate system of the multiple prisms: the maximum movement distance of the prism on a certain coordinate axis is the car-to-snow distance, and a relative shortest distance exists correspondingly. Defining the total mileage difference of a certain path in the directions of all coordinate axes as the maximum road difference:
for ease of calculation, a maximum road-to-difference ratio is introduced:
s3, constructing a prism motion inverse solution model: converting points in a pixel coordinate system into corresponding prism rotation angle values by a two-step method, planning a point set, and passing through gamma 2 And transforming and mapping coordinates, and drawing a multi-target map in a multi-prism coordinate system. Because two groups of equivalent solutions exist in the rotating biprism, points in the 16 pixel coordinate system form a multi-target solution point map of 32 points in the rotating biprism coordinate system, and the multi-target solution point map is used as a planning target point of prism scanning movement.
S4, planning a motion path of the rotary biprism: in a multi-target solution point map of a multi-prism coordinate system, 16 points to be passed and equivalent points thereof are all arranged, each path only moves along a coordinate axis and has a certain length, and a straight line path which meets a planning target and passes through each solution point exactly once is solved. In this embodiment, the path planning is performed using an ant colony algorithm combined with a tabu table.
S41, for the service life of the whole machine, the shortest path loss is minimum; but for search efficiency, the fastest path can complete a given target scan in the shortest time. The example calculates two scanning targets in parallel and respectively plans the corresponding optimal paths.
S42, in order to ensure stable driving and transmission of the prism, the prism keeps continuous and same-direction operation. The operation mode of the rotary biprism is as follows: all forward rotation; full inversion; prism 1 rotates forward and prism 2 rotates backward; prism 1 rotates in reverse and prism 2 rotates in forward direction, labeled mode++/Mode-/mode+/mode++, respectively.
S43, according to different scan target plans, an ant colony algorithm combined with a tabu list is called, and path feature diagrams of four prism movement modes are calculated and drawn in the shortest distance/fastest distance mode.
As shown in fig. 4, the total distance of each path on the coordinate axis in the graph is the sum of angles rotated by each prism in the prism scanner, and is represented by driving energy and system loss required for completing one scanning; the difference of the moving distances of each path from the starting point to the ending point in the X direction and the Y direction is the total path difference of the operation of the biprism; the tortuosity of each path shows the smoothness of the scanning path, and reflects the acceleration and deceleration conditions and the waiting conditions of the prism.
Analyzing the shortest path, the fastest path and the maximum path difference of each path, and finally selecting the optimal path under the shortest distance target according to the forward rotation mode of the prism 1 and the reverse rotation of the prism 2 according to the scanning target; the prism 1 is inverted and the preferred path in the prism 2 inversion mode is the best path at the fastest distance target.
S5, controlling the prism scanner to sequentially complete scanning of each target point: when the host finishes the optimal searching path planning, the motion instructions are synchronously pushed into the prism motion controller by using a position-velocity-time data form, and the biprism is rotated to search targets in sequence according to the target point sequence after path optimization, so that all targets are traversed.
S6, constructing a prism movement forward direction model: and synchronously calculating the estimated laser pointing by using an iterative vector refraction method, forming an estimated target point map in a view field coordinate system of the prism scanner, and feeding back scanning pointing information.
To highlight the corner planning advantage of traversing the target trajectory under the prismatic coordinate system, a comparison is made using the target map that plans the traditional pixel coordinate system, the result is shown in fig. 5.
The present embodiment is based on a rotating biprism scanner, using a multiple prism coordinate system for prism scan path planning. The result shows that the multi-prism coordinate system can effectively improve the traversing searching efficiency. Compared with the traditional path planning, the method has the advantages that the driving energy and the system loss are obviously reduced, and the whole scanning time is reduced to half of the original time. The multiple prism coordinate system can realize complete description of the motion state of the prism scanner and provide path planning basis for scanning and tracking of a large-range, long-distance and multi-target. The planned optimal path can reduce the overall energy consumption of the prism, and has higher running smoothness and prism utilization rate.
The foregoing describes in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be made in accordance with the concepts of the invention by one of ordinary skill in the art without undue burden. Therefore, all technical solutions which can be obtained by logic analysis, reasoning or limited experiments based on the prior art by the person skilled in the art according to the inventive concept shall be within the scope of protection defined by the claims.
Claims (10)
1. A coordinate system construction method, applied to a cascading prism set, comprising:
establishing an n-dimensional coordinate system, wherein n is equal to the number of prisms in the cascade prism group, and defining points under the coordinate system: each coordinate axis corresponds to the independent movement angle of different prisms, and one coordinate axis point in the coordinate system represents the prism state at a certain moment;
defining the inter-point distance in the coordinate system: the distance between two points in the coordinate system is expressed as:
in the shortest distance mode:
wherein ,θid Representing the projection value of point a on coordinate axis i, θ ib Representing the projection of point b on coordinate axis i,
representing all coordinate axis distances between the point a and the point b, wherein the point a and the point b represent the moment t a Next time t b Prism state, D mk Representing the total movement distance of the prism when the object points are in the shortest distance mode;
since the prism rotation is performed simultaneously, in the fastest distance mode:
defining the inter-point road difference under a coordinate system:
wherein ,
representing the maximum road difference between the point a and the point b; d (D) d The maximum total road difference of the prism at the l target points is indicated.
2. A coordinate system construction method according to claim 1, characterized in that it facilitates calculation of the reference maximum road-to-difference ratio:
I d representing the maximum road-to-difference ratio between the i target points.
3. The multi-target detection scanning method of the prism scanner is characterized in that the prism scanner comprises a laser radar emitter, a vision guiding range finding camera, a cascading prism group and a support control system, wherein the vision guiding range finding camera is arranged on a paraxial of the laser radar emitter, and the cascading prism group is coaxially arranged in front of the laser radar emitter in a plane parallel manner, and the scanning method comprises the following steps:
s1, calibrating camera internal parameters, obtaining an imaging model of a vision-guided ranging camera, and establishing a conversion relation between a world coordinate system and a pixel coordinate system; shooting a plurality of long-distance targets by using a vision-guided ranging camera, and identifying and marking the targets in the acquired images to obtain a target point map in a pixel coordinate system;
s2, establishing a multiple prism coordinate system by using the coordinate system construction method according to any one of claims 1-2, wherein the movement angle of the prism is a function of time t;
s3, establishing a reverse resolving relation between an optical axis pointing angle and a motion value of each prism, and realizing conversion from a pixel coordinate system to a multiple prism coordinate system;
s4, in a multiple prism coordinate system, abstracting the prism scanner motion planning into a multipoint tourist problem, and planning multiple prism motion paths;
s5, controlling the prism scanner to sequentially complete scanning of each target point according to the planned multiple prism motion paths.
4. A method of multi-target scout scanning for a prismatic scanner according to claim 3, further comprising:
s6, calculating emergent laser directions according to the planned multiple prism motion paths by using an iterative vector method, forming an estimated target point map in a world coordinate system, comparing and feeding back the estimated target point map with the target point map obtained by the actual scanning directions in the step S5, and correcting the prism scanner motion.
5. A multi-object scanning method for a prism scanner according to claim 3, wherein in step S1, the camera reference is calibrated using Zhang Zhengyou method.
6. A multi-object detection scanning method for a prism scanner according to claim 3, wherein in step S4, the shortest path or the fastest path or a weighted combination of both are used as the optimization object.
7. A multi-object scanning method for a prism scanner according to claim 3, wherein in step S4, the cascaded prism groups generate 2n types of motion modes, wherein n is the number of prisms.
8. The method of claim 3, wherein in step S4, prism motion path feature diagrams are drawn according to the rule of homodromous operation for the obtained multiple prism motion paths, and shortest distance, fastest distance and maximum road difference ratio are used as the criteria of path.
9. The utility model provides a many targets of prism scanner survey scanning system, its characterized in that, the prism scanner includes laser radar transmitter, vision guide range finding camera, cascade prism group and support control system, the vision guide range finding camera sets up at laser radar transmitter paraxial, cascade prism group is coaxial and the plane parallel is arranged in the laser radar transmitter in front, scanning system includes:
the pixel coordinate system module is used for calibrating the internal parameters of the camera, obtaining an imaging model of the vision-guided ranging camera, and establishing a conversion relation between a world coordinate system and the pixel coordinate system; shooting a plurality of long-distance targets by using a vision-guided ranging camera, and identifying and marking the targets in the acquired images to obtain a target point map in a pixel coordinate system;
a multiple prism coordinate system module for establishing a multiple prism coordinate system using the coordinate system construction method according to any one of claims 1-2, the movement angle of the prism being a function of time t;
the coordinate conversion module is used for establishing a reverse resolving relation between the optical axis pointing angle and the motion value of each prism and realizing conversion from a pixel coordinate system to a multiple prism coordinate system;
the planning module is used for abstracting the motion planning of the prism scanner into a multi-point travel business problem in a multi-prism coordinate system and planning a multi-prism motion path;
and the scanning control module is used for controlling the prism scanner to sequentially complete the scanning of each target point according to the planned multiple prism movement path.
10. The prismatic scanner multi-target detection scanning system of claim 9, further comprising:
the feedback correction module is used for calculating emergent laser directions by using an iterative vector method according to the planned multiple prism motion paths, forming an estimated target point map in a world coordinate system, comparing and feeding back the estimated target point map with a target point map obtained by actual scanning directions in the scanning control module, and correcting the prism scanner motion of the scanning control module.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116772744A (en) * | 2023-08-24 | 2023-09-19 | 成都量芯集成科技有限公司 | 3D scanning device and method based on laser ranging and vision fusion |
| CN117519212A (en) * | 2024-01-03 | 2024-02-06 | 杭州华橙软件技术有限公司 | Path tracking control method, device, terminal and computer readable storage medium |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116772744A (en) * | 2023-08-24 | 2023-09-19 | 成都量芯集成科技有限公司 | 3D scanning device and method based on laser ranging and vision fusion |
| CN116772744B (en) * | 2023-08-24 | 2023-10-24 | 成都量芯集成科技有限公司 | 3D scanning device and method based on laser ranging and vision fusion |
| CN117519212A (en) * | 2024-01-03 | 2024-02-06 | 杭州华橙软件技术有限公司 | Path tracking control method, device, terminal and computer readable storage medium |
| CN117519212B (en) * | 2024-01-03 | 2024-04-12 | 杭州华橙软件技术有限公司 | Path tracking control method, device, terminal and computer readable storage medium |
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