阅读说明：本技术 一种基于单扫描头激光雷达扩大建图视场的方法及系统 (Method and system for enlarging mapping view field based on single scanning head laser radar ) 是由 蒋涛 赵勤学 刘西营 赵锐 魏飞翔 商春雷 吕文强 亓孝武 王祥楷 李凯旋 于 2021-09-03 设计创作，主要内容包括：本发明属于涉及三维激光点云处理技术领域,提供了一种基于单扫描头激光雷达扩大建图视场的方法及系统。该方法包括,对单扫描头激光雷达采集的目标视场的激光点云进行区段划分；对同一区段内相邻帧依次进行数据配准；对同一区段内不相邻帧进行数据配准验证,若正确,则遍历所有区段执行数据配准过程和数据配准验证的过程,否则,加强同一区段内相邻帧数据配准过程的迭代条件,执行数据配准和数据配准验证的过程；对配准后的激光点云进行拼接。(The invention belongs to the technical field of three-dimensional laser point cloud processing, and provides a method and a system for enlarging a mapping view field based on a single scanning head laser radar. The method comprises the steps of dividing a laser point cloud of a target view field collected by a single scanning head laser radar into sections; sequentially carrying out data registration on adjacent frames in the same section; performing data registration verification on nonadjacent frames in the same section, traversing all sections to perform a data registration process and a data registration verification process if the nonadjacent frames in the same section are correct, or reinforcing the iteration condition of the data registration process of adjacent frames in the same section to perform the data registration and the data registration verification process; and splicing the registered laser point clouds.)

1. A method for enlarging a mapping view field based on a single scanning head laser radar is characterized by comprising the following steps:

dividing a section of a laser point cloud of a target view field acquired by a single scanning head laser radar;

sequentially carrying out data registration on adjacent frames in the same section;

performing data registration verification on nonadjacent frames in the same section, traversing all sections to perform a data registration process and a data registration verification process if the nonadjacent frames in the same section are correct, or reinforcing the iteration condition of the data registration process of adjacent frames in the same section to perform the data registration and the data registration verification process;

and splicing the registered laser point clouds.

2. The method of claim 1, wherein the laser point clouds of the target field of view are consecutive in time sequence and the data overlap ratio of adjacent frames is greater than 60%.

3. The method for enlarging a mapping field of view based on a single scan head lidar according to claim 1, wherein the segmentation comprises: dividing adjacent multi-frame laser point clouds into the same section, wherein the laser point clouds in the same section have scanning data aiming at the same target point.

4. The method for enlarging a mapping field of view based on a single scan head lidar according to claim 1, wherein the segmentation comprises: one section at least comprises three frames, any frame of laser point cloud is necessarily in one section, and at most the same frame of laser point cloud is included among different sections.

5. The method for enlarging the mapping field of view based on the single-scanning-head laser radar as claimed in claim 1, wherein the data registration process comprises:

obtaining an error value of the inertial navigation device based on inertial navigation pose data acquired by a single scanning head laser radar and by combining an error relation between the laser radar and the inertial navigation device;

based on the characteristic point set of the laser point cloud, combining a source point cloud matrix in two adjacent frames of laser point clouds, a target point cloud matrix and a translation matrix in the two adjacent frames of laser point clouds to obtain a deviation value of the laser point cloud;

obtaining an integral offset model based on a norm of a square sum of an error value of the inertial navigation device and a deviation value of the laser point cloud;

and carrying out iterative calculation of an ICP point cloud registration algorithm on the whole offset model based on a point set formed by adjacent frames in the same section until an initial iterative condition is reached, and finishing data registration.

6. The method for enlarging the mapping view field based on the single-scanning-head lidar according to claim 1, wherein the single-scanning-head lidar acquiring the laser point cloud of the target view field comprises:

carrying out laser point cloud collection according to a specified scanning operation standard;

the prescribed scan job criteria include:

the acquisition route forms a closed loop; or

Acquiring position point information of an initial position and position point information of an end position of an acquisition route through a geographic information module; or

The position point information of at least one target point existing in the target field of view is known.

7. The method for enlarging the field of view of a map based on a single scan head lidar according to claim 1, wherein enforcing the iteration condition comprises: and reaching a specific iteration number or converging the iteration to a specific value, wherein the specific iteration number is greater than the iteration number in the initial iteration condition, and the specific value is less than a set threshold value in the initial iteration condition.

8. A system for enlarging a mapping field of view based on a single scan head lidar, comprising:

a partitioning module configured to: dividing a section of a laser point cloud of a target view field acquired by a single scanning head laser radar;

a data registration module configured to: sequentially carrying out data registration on adjacent frames in the same section;

a data registration validation module configured to: performing data registration verification on nonadjacent frames in the same section, traversing all sections to perform a data registration process and a data registration verification process if the nonadjacent frames in the same section are correct, or reinforcing the iteration condition of the data registration process of adjacent frames in the same section to perform the data registration and the data registration verification process;

a stitching module configured to: and splicing the registered laser point clouds.

9. A computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, carries out the steps of the method for enlarging a patterned field of view based on a single-scan head lidar according to any one of claims 1 to 7.

10. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor when executing the program implements the steps in the method for enlarging a patterned field of view based on a single scan head lidar according to any of claims 1-7.

Technical Field

The invention belongs to the technical field of three-dimensional laser point cloud processing, and particularly relates to a method and a system for enlarging a mapping view field based on a single scanning head laser radar.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

At present, the laser radar can collect three-dimensional laser point cloud data in indoor and outdoor environments. An environmental image, i.e., a map, of the scanned target field of view can be reconstructed based on the three-dimensional laser point cloud data.

The scanning field of view of the single-scanning-head laser radar is usually limited, and the laser point cloud obtained by scanning is limited in a narrow range, so that the industrial requirements cannot be directly met. It is an urgent technical problem to be solved by those skilled in the art to expand the mapping field of view of the single-scan head lidar.

The existing laser point cloud splicing method cannot verify the splicing accuracy and cannot systematically judge the validity of the splicing result.

Disclosure of Invention

In order to solve the technical problems in the background art, the invention provides a method and a system for enlarging a mapping view field based on a single-scanning-head laser radar, which can efficiently and accurately enlarge the mapping view field of the single-scanning-head laser radar.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a method for enlarging a mapping view field based on a single scanning head laser radar.

A method for enlarging a mapping field of view based on a single scanning head laser radar comprises the following steps:

dividing a section of a laser point cloud of a target view field acquired by a single scanning head laser radar;

sequentially carrying out data registration on adjacent frames in the same section;

performing data registration verification on nonadjacent frames in the same section, traversing all sections to perform a data registration process and a data registration verification process if the nonadjacent frames in the same section are correct, or reinforcing the iteration condition of the data registration process of adjacent frames in the same section to perform the data registration and the data registration verification process;

and splicing the registered laser point clouds.

Further, the laser point clouds of the target view field are continuous in time sequence, and the data overlapping rate of adjacent frames is more than 60%.

Further, the process of partitioning the sector includes: dividing adjacent multi-frame laser point clouds into the same section, wherein the laser point clouds in the same section have scanning data aiming at the same target point.

Further, the process of partitioning the sector includes: one section at least comprises three frames, any frame of laser point cloud is necessarily in one section, and at most the same frame of laser point cloud is included among different sections.

Further, the process of data registration includes:

obtaining an error value of the inertial navigation device based on inertial navigation pose data acquired by a single scanning head laser radar and by combining an error relation between the laser radar and the inertial navigation device;

based on the characteristic point set of the laser point cloud, combining a source point cloud matrix in two adjacent frames of laser point clouds, a target point cloud matrix and a translation matrix in the two adjacent frames of laser point clouds to obtain a deviation value of the laser point cloud;

obtaining an integral offset model based on a norm of a square sum of an error value of the inertial navigation device and a deviation value of the laser point cloud;

and carrying out iterative calculation of an ICP point cloud registration algorithm on the whole offset model based on a point set formed by adjacent frames in the same section until an initial iterative condition is reached, and finishing data registration.

Further, the process of acquiring the laser point cloud of the target view field by the single scanning head laser radar comprises the following steps:

carrying out laser point cloud collection according to a specified scanning operation standard;

the prescribed scan job criteria include:

the acquisition route forms a closed loop; or

Acquiring position point information of an initial position and position point information of an end position of an acquisition route through a geographic information module; or

The position point information of at least one target point existing in the target field of view is known.

Further, the enforcing the iteration condition includes: and reaching a specific iteration number or converging the iteration to a specific value, wherein the specific iteration number is greater than the iteration number in the initial iteration condition, and the specific value is less than a set threshold value in the initial iteration condition.

A second aspect of the invention provides a system for enlarging a field of view of a build based on a single scan head lidar.

A system for enlarging a field of view of a map based on a single scan head lidar comprising:

a partitioning module configured to: dividing a section of a laser point cloud of a target view field acquired by a single scanning head laser radar;

a data registration module configured to: sequentially carrying out data registration on adjacent frames in the same section;

a data registration validation module configured to: performing data registration verification on nonadjacent frames in the same section, traversing all sections to perform a data registration process and a data registration verification process if the nonadjacent frames in the same section are correct, or reinforcing the iteration condition of the data registration process of adjacent frames in the same section to perform the data registration and the data registration verification process;

a stitching module configured to: and splicing the registered laser point clouds.

A third aspect of the invention provides a computer-readable storage medium.

A computer-readable storage medium, having stored thereon a computer program which, when being executed by a processor, carries out the steps of the method for enlarging a patterned field of view based on a single-scan-head lidar as defined in the first aspect above.

A fourth aspect of the invention provides a computer apparatus.

A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor when executing the program implementing the steps in the method for enlarging a field of view of a map based on a single scan head lidar as described in the first aspect above.

Compared with the prior art, the invention has the beneficial effects that:

the method adopts a data registration method, can enlarge the mapping view field of the single-scanning-head laser radar, effectively improves the accuracy of the data registration process and improves the mapping efficiency.

Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

FIG. 1 is a schematic flow chart of a method for enlarging a built view field based on a single-scanning-head laser radar according to the present invention;

FIG. 2A is a schematic diagram of a first embodiment of the division of the multi-frame laser point cloud segment according to the present invention;

FIG. 2B is a schematic diagram of a second embodiment of the division of the multi-frame laser point cloud segments according to the present invention;

FIG. 2C is a schematic diagram of a third embodiment of the division of the multi-frame laser point cloud segment according to the present invention;

FIG. 3 is a schematic diagram illustrating a process of implementing data registration by using a point cloud ICP algorithm according to the present invention;

fig. 4 is a schematic diagram illustrating a flow of realizing data registration by using a point cloud ICP algorithm according to the present invention.

Detailed Description

The invention is further described with reference to the following figures and examples.

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

It is noted that the flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of methods and systems according to various embodiments of the present disclosure. It should be noted that each block in the flowchart or block diagrams may represent a module, a segment, or a portion of code, which may comprise one or more executable instructions for implementing the logical function specified in the respective embodiment. It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

Example one

As shown in fig. 1, the present embodiment provides a method for enlarging a mapping field of view based on a single-scan head laser radar, including:

dividing a section of a laser point cloud of a target view field acquired by a single scanning head laser radar;

sequentially carrying out data registration on adjacent frames in the same section;

performing data registration verification on nonadjacent frames in the same section, traversing all sections to perform a data registration process and a data registration verification process if the nonadjacent frames in the same section are correct, or reinforcing the iteration condition of the data registration process of adjacent frames in the same section to perform the data registration and the data registration verification process;

and splicing the registered laser point clouds.

Specifically, the technical scheme of the invention can be realized by adopting the following steps:

step 1, carrying out laser point cloud collection on a target view field by using a single scanning head laser radar, wherein the collected laser point clouds are continuous in time sequence, and the data overlapping rate of adjacent frames is more than 60%.

The single scanning head laser radar can be a handheld laser radar so as to be convenient for collecting continuous and dynamic laser point clouds in narrow spaces such as galleries and basements.

In an optimized embodiment, the single scanning head laser radar is generally required to perform laser point cloud collection according to a specified scanning operation standard. The prescribed scan job criteria includes at least any one of:

1. and acquiring a route stroke closed loop. That is, the acquisition path may start from a starting point, reach a midpoint, and finally return to the starting point.

2. The initial position and the end position of the collection route can be collected by the geographic information module to obtain the position point information. That is, the initial position and the end position have known their GPS information.

3. The position point information of at least one target point existing in the target field of view is known.

The prescribed scanning operation standard can help to improve the accuracy of mapping. A verification process of data registration is facilitated.

In addition, in step 1, inertial navigation pose data, i.e., IMU data, can also be acquired using the single-scan-head lidar. The single scanning head laser radar is provided with an IMU inertial navigation unit. And synchronizing the inertial navigation pose data and the laser point cloud data clock.

And 2, carrying out section division on the collected laser point cloud.

The method comprises the steps of continuously scanning by a single scanning head laser radar to obtain multi-frame laser point clouds, dividing the adjacent multi-frame laser point clouds into the same section, and enabling the laser point clouds in the same section to have scanning data aiming at the same target point. That is, the laser point clouds in the same section all scan the same target object in the environment, and the laser point cloud data of the target object is recorded.

Any frame of laser point cloud is necessarily in one sector, i.e. no frame of laser point cloud is allocated into a sector, independent of the sector.

For example, as shown in FIG. 2A, the 1-3 frames of the laser point cloud are divided into a first section D1, the 4-6 frames are divided into a second section D2, the 7-9 frames are divided into a third section D3, and so on.

In addition, other ways of dividing the sections are also included, as shown in fig. 2B, the 1 st to 3 rd frames of the laser point cloud are divided into a first section D1, the 2 nd to 4 th frames are divided into a second section D2, the 3 rd to 5 th frames are divided into a third section D3, and so on.

As shown in FIG. 2C, the 1-3 frames of laser point cloud are divided into a first section D1, the 3-5 frames are divided into a second section D2, the 5-7 frames are divided into a third section D3, and so on.

The three division cases are only three division ways of the present invention, including but not limited to the above cases. The same frame of laser point cloud is not included among different sections of the invention, or the same frame of laser point cloud is included among different sections.

And 3, sequentially carrying out point cloud ICP algorithm on adjacent frames in the same section to realize data registration.

As shown in fig. 3, the step 3 further includes:

and 301, constructing an error formula of the laser radar and the inertial navigation device according to the inertial navigation pose data.

Constructing an error equation of the IMU inertial navigation device:

E_B＝δp_k ^k+1

E_Band representing the error of the IMU inertial navigation device. δ p_k ^k+1And the displacement error of the IMU inertial navigation device from the kth frame to the k +1 frame under the laser radar coordinate system is represented.

The IMU main offset is that the acceleration quadratic integral obtains the displacement, and in order to reduce the calculated amount, the error of the IMU inertial navigation device is simplified to E_BErrors in speed and angle are ignored.

Step 302, constructing a deviation formula E of the laser point cloud according to the laser point cloud_L。

Constructing a deviation equation of the laser point cloud according to the collected characteristic point set of the laser point cloud as follows:

wherein R represents a rotation matrix, A_iI point and B point representing source point clouds in two adjacent frames of laser point clouds_iAnd (3) representing the ith point of the target point cloud in two adjacent frames of laser point clouds, and t representing a translation matrix.

The initial conversion matrix of the two adjacent frames of laser point clouds is as follows:

wherein T is_k ^-1Represents the inverse of IMU pose corresponding to the kth frame of laser point cloud, T_k+1And representing the pose of the IMU inertial navigation unit corresponding to the point cloud of the (k + 1) th frame.

Step 303, constructing an overall offset formula according to the error formula and the deviation formula.

Global offset formula E:

and 304, performing ICP algorithm iterative computation on the overall offset formula based on the point set formed by the adjacent frames to reach an initial iterative condition, and realizing data registration.

The iterative computation of the ICP algorithm includes, as shown in fig. 4:

3041, get two adjacent frames of laser point clouds and record them as source point cloud A_i＝(x_i y_i z_i) And a target point cloud B_j＝(x_jy_j z_j) Wherein i belongs to (1,2, 3., n), j belongs to (1,2, 3., m), wherein (x y z) is a coordinate value of the laser point cloud under a laser radar coordinate system L, n represents the number of source point clouds, and m represents the number of target point clouds.

Step 3042, determining an angular point set and a plane point set corresponding to two adjacent frames of laser point clouds according to the principle of minimizing the euclidean distance between two points.

Step 3043, taking the initial transformation matrix as an initial value, performing ICP algorithm iterative computation on the overall offset formula E to obtain an optimal transformation matrix, where the optimal transformation matrix minimizes the overall offset equation value.

Step 3044, transforming the target point cloud by using the optimal transformation matrix to obtain a new target point cloud.

Step 3045, calculate the average distance d between the new target point cloud and the source point cloud:

in the formula B_i' denotes a new target point cloud.

Step 3046, when the average distance d meets the initial iteration condition, that is, less than the set distance threshold λ or the iteration number reaches the set iteration number N, stopping the iterative computation, and using the obtained optimal transformation matrix as the final optimal transformation matrix, implementing data registration, and thus performing laser point cloud splicing. If the initial iteration condition is not met, step 3042 is performed.

By performing the above-mentioned step 301-306 for each two adjacent frames in turn, data registration is achieved.

And 4, performing a point cloud ICP algorithm on non-adjacent frames in the same section to verify the correctness of the data registration, if the data registration is correct, executing the step 3 aiming at the next section until all the sections are traversed, and if the data registration is incorrect, executing the step 3 aiming at the section again and adopting a reinforced iteration condition. The reinforced iteration condition includes: reaching a certain number of iterations or the iterations converging to a certain value. The specific iteration number is greater than the iteration number in the initial iteration condition, and the specific value is less than a set distance threshold lambda in the initial iteration condition. I.e. the iteration is continued with more stringent iteration conditions.

In step 3, the registration is performed sequentially for adjacent frames in the same section, for example, 1 st and 2 nd frames, and 2 nd and 3 rd frames. In step 4, the registration in the section needs to be verified, namely, the registration is realized through the registration of non-adjacent frames, and the point cloud ICP algorithm in step 3 is executed on the 1 st and 3 rd frames. The point cloud ICP algorithm can also be carried out on the head frame and the tail frame in the same section.

Through the verification of the step 4, the situation that correction cannot be realized if errors occur in the process of sequentially executing the point cloud ICP algorithm on adjacent frames can be avoided. The invention can verify in the section in a staged manner at any time, and improve the accuracy of registration. Therefore, an accurate data source is provided for subsequent laser point cloud splicing.

And 5, splicing the registered laser point clouds.

Example two

The embodiment provides a system for enlarging a mapping view field based on a single-scanning-head laser radar.

A system for enlarging a field of view of a map based on a single scan head lidar comprising:

a partitioning module configured to: dividing a section of a laser point cloud of a target view field acquired by a single scanning head laser radar;

a data registration module configured to: sequentially carrying out data registration on adjacent frames in the same section;

a data registration validation module configured to: performing data registration verification on nonadjacent frames in the same section, traversing all sections to perform a data registration process and a data registration verification process if the nonadjacent frames in the same section are correct, or reinforcing the iteration condition of the data registration process of adjacent frames in the same section to perform the data registration and the data registration verification process;

a stitching module configured to: and splicing the registered laser point clouds.

It should be noted here that the dividing module, the data registration verification module, and the splicing module are the same as the examples and application scenarios realized by the corresponding steps of the embodiment, but are not limited to the disclosure of the first embodiment. It should be noted that the modules described above as part of a system may be implemented in a computer system such as a set of computer-executable instructions.

EXAMPLE III

The present embodiment provides a computer-readable storage medium, on which a computer program is stored, which when executed by a processor implements the steps in the method for enlarging a patterned field of view based on a single-scan-head lidar as described in the first embodiment above.

Example four

The embodiment provides a computer device, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor executes the program to realize the steps of the method for enlarging the mapping field based on the single-scanning-head laser radar as described in the first embodiment.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), or the like.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.