CN116359890A

CN116359890A - Mobile measurement system calibration method, device and equipment

Info

Publication number: CN116359890A
Application number: CN202310389248.0A
Authority: CN
Inventors: 李永富; 王志强; 石亮亮
Original assignee: Beijing Siwei Wanxing Technology Co ltd
Current assignee: Beijing Siwei Wanxing Technology Co ltd
Priority date: 2023-04-12
Filing date: 2023-04-12
Publication date: 2023-06-30

Abstract

The embodiment of the specification discloses a mobile measurement system calibration method, a device and equipment, wherein the scheme comprises the following steps: acquiring target calibration data acquired by the mobile measurement system at a preset road section; resolving point cloud data acquired by laser radar equipment at the mobile measurement system in the target calibration data to obtain first coordinate data of a target object after data acquired along a first direction are resolved and second coordinate data of the target object after data acquired along a second direction are resolved; and adjusting the placement parameters of the laser radar according to the first coordinate data and the second coordinate data to obtain the calibrated placement parameters of the laser radar. Based on the scheme of the invention, the calibration efficiency and the calibration precision of the laser radar placement parameters are improved.

Description

Mobile measurement system calibration method, device and equipment

Technical Field

The present disclosure relates to the field of mobile measurement technologies, and in particular, to a method, an apparatus, and a device for calibrating a mobile measurement system.

Background

The mobile measurement system integrates sensors such as a laser radar, a GNSS (global navigation satellite system), an IMU (inertial measurement unit) and the like, and can rapidly acquire high-precision point cloud data of buildings around a road so as to acquire space information of the ground feature and the relief. In mobile measurement systems, the lidar, GNSS, IMU, etc. sensors are mounted on a rigid platform, and the entire platform is mounted on a mobile vehicle. In the vehicle advancing process, laser point cloud data, position data of the IMU and inertial navigation data (including pitch angle, roll angle and course angle) of the IMU are synchronously collected, and various data are strictly synchronized through time. Calibrating the placement parameters of the laser radar in the mobile measurement system is actually to solve the rotation and translation parameters of the laser coordinate system where the laser radar is located relative to the inertial navigation coordinate system where the IMU is located.

The current method for calibrating the laser radar placement parameters mainly comprises the steps of establishing a calibration field, arranging a plurality of target points in the calibration field, measuring three-dimensional coordinates of each target point by using a total station, scanning the calibration field by using the laser radar, and calculating 6 placement parameters of the laser radar by using point cloud data which are understood later and existing high-precision control point data by using a least square method.

However, the construction of the calibration field requires the use of specialized instruments and equipment such as precise total stations, base stations and the like, and the calibration field needs to be regularly maintained every year, so that more resources are required to be put into the construction and maintenance of the overall calibration field. In addition, in the traditional control point calibration method, by extracting characteristic angular points of point cloud and performing least square nonlinear fitting on the control points, the characteristic points of the point cloud are required to be clear and complete, the laser radar points are limited in frequency, the points of objects imaged by lasers are sparser when the distance is longer, so that the distance of the characteristic angular points of the fitted point cloud is limited, the calibrated parameters can possibly generate non-global solution, so that the deviation of the precision of the point cloud at the longer position is larger, the distance between the control points and the laser radar is more than 40 meters, and the calibration precision cannot be ensured after the distance exceeds 40 meters.

Disclosure of Invention

In view of this, the embodiments of the present disclosure provide a calibration method, device and equipment for a mobile measurement system, which are used for reducing calibration cost and increasing the application range of the calibration method on the basis of increasing the calibration efficiency and calibration accuracy of the laser radar installation parameters.

In order to solve the above technical problems, the embodiments of the present specification are implemented as follows:

the embodiment of the specification provides a calibration method of a mobile measurement system, which comprises the following steps:

acquiring target calibration data acquired by the mobile measurement system at a preset road section; the target calibration data are data acquired in the process that the vehicle with the mobile measurement system is respectively driven along a first direction and a second direction at the preset road section, and the second direction is opposite to the first direction.

And resolving point cloud data acquired by the laser radar equipment at the mobile measurement system in the target calibration data to obtain first coordinate data of a first position of a target object in the preset road section in a world coordinate system acquired along the first direction and second coordinate data of a second position of the target object in the preset road section in the world coordinate system acquired along the second direction.

And taking the first position and the second position of the target object as adjustment targets, and adjusting the placement parameters of the laser radar according to the first coordinate data and the second coordinate data to obtain the placement parameters after calibration of the laser radar.

The embodiment of the specification provides a mobile measurement system calibration device, which comprises:

the first acquisition module is used for acquiring target calibration data acquired by the mobile measurement system at a preset road section; the target calibration data are data acquired in the process that the vehicle with the mobile measurement system is respectively driven along a first direction and a second direction at the preset road section, and the second direction is opposite to the first direction.

The calculation module is used for calculating the point cloud data acquired by the laser radar equipment at the mobile measurement system in the target calibration data to obtain first coordinate data of a first position of a target object in the preset road section in a world coordinate system acquired along the first direction and second coordinate data of a second position of the target object in the preset road section in the world coordinate system acquired along the second direction.

And the adjusting module is used for adjusting the placement parameters of the laser radar according to the first coordinate data and the second coordinate data by taking the superposition of the first position and the second position of the target object as an adjusting target, so as to obtain the placement parameters after the calibration of the laser radar.

at least one processor; the method comprises the steps of,

a memory communicatively coupled to the at least one processor; wherein,,

the memory stores instructions executable by the at least one processor to enable the at least one processor to:

At least one embodiment provided in this specification enables the following benefits:

after target calibration data acquired by the mobile measurement system at a preset road section are acquired by the calibration system, the point cloud data in the target calibration data are resolved, first coordinate data and second coordinate data of a target object can be obtained, then the placement parameters of the laser radar at the mobile measurement system are adjusted according to the first coordinate data and the second coordinate data of the target object, and finally the placement parameters after the calibration of the laser radar are obtained. Based on the scheme of the invention, a professional calibration field is not required to be established in advance, thereby being beneficial to reducing the cost of calibrating the laser radar setting parameters and improving the calibration efficiency and accuracy of the laser radar setting parameters.

In addition, in the scheme of the invention, the target object aimed at by the point cloud data acquisition can be a characteristic surface instead of the traditional calibration by using the control points, so that the laser radar has smaller point frequency limit, can be suitable for the target object farther away from the laser radar, and is further beneficial to improving the calibration precision of the laser radar placement parameters and the application range of the calibration scheme.

Drawings

In order to more clearly illustrate the embodiments of the present description or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present application, and that other drawings may be obtained according to these drawings without inventive effort to a person skilled in the art.

Fig. 1 is a schematic diagram of an application scenario of a calibration method of a mobile measurement system according to an embodiment of the present disclosure;

FIG. 2 is a schematic flow chart of a calibration method of a mobile measurement system according to an embodiment of the present disclosure;

FIG. 3 is a schematic structural diagram of a calibration device of the mobile measurement system corresponding to FIG. 2 according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a calibration device of the mobile measurement system corresponding to fig. 2 according to an embodiment of the present disclosure.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of one or more embodiments of the present specification more clear, the technical solutions of one or more embodiments of the present specification will be clearly and completely described below in connection with specific embodiments of the present specification and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present specification. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without undue burden, are intended to be within the scope of one or more embodiments herein.

The following describes in detail the technical solutions provided by the embodiments of the present specification with reference to the accompanying drawings.

In the prior art, the method for calibrating the laser radar placement parameters mainly comprises the steps of pre-establishing a calibration field, then scanning the calibration field by using the laser radar, and obtaining the placement parameters of the laser radar by using point cloud data which are understood later and existing high-precision control point data. However, the construction and maintenance of the calibration field requires more resources. In addition, in the traditional control point calibration method, the characteristic angular points of the point cloud are extracted to perform least square nonlinear fitting with the control points, so that the characteristic points of the point cloud are required to be clear and complete, the laser radar points are limited in frequency, the number of the object points imaged by the laser is sparse the farther the distance is, the point cloud precision deviation at the farther position is larger, and the accuracy of the calibration result of the placement parameters of the laser radar is lower.

In order to solve the drawbacks of the prior art, the present solution provides the following embodiments:

fig. 1 is a schematic diagram of an application scenario of a calibration method of a mobile measurement system according to an embodiment of the present disclosure.

As shown in fig. 1, in the present embodiment, the mobile measurement system 101 may include a lidar device, a global navigation satellite system, and an inertial navigation device. The vehicle with the mobile measurement system 101 can travel back and forth along the road on a preset road section, and the mobile measurement system 101 can collect target calibration data during the travel of the vehicle. After the mobile measurement system 101 collects target calibration data, the data can be sent to the calibration system 102, after the calibration system 102 obtains the target calibration data, point cloud data, which are in the target calibration data and are collected by the laser radar equipment at the mobile measurement system 101, can be resolved, and the placement parameters of the laser radar are adjusted according to the resolving result, so that the placement parameters after the calibration of the laser radar are obtained.

In the scheme in fig. 1, after the calibration system acquires target calibration data acquired by the mobile measurement system at a preset road section, resolving point cloud data in the target calibration data to obtain first coordinate data and second coordinate data of a target object, and adjusting the positioning parameters of the laser radar at the mobile measurement system according to the first coordinate data and the second coordinate data of the target object to finally obtain the calibrated positioning parameters of the laser radar. Therefore, a professional calibration field is not required to be established in advance, the cost for calibrating the laser radar placement parameters is reduced, and the calibration efficiency and accuracy of the laser radar placement parameters are improved.

Next, a method for calibrating a mobile measurement system provided for the embodiments of the present disclosure will be specifically described with reference to the accompanying drawings:

fig. 2 is a flow chart of a calibration method of a mobile measurement system according to an embodiment of the present disclosure. The implementation subject of the scheme in fig. 2 may be a calibration system, or an application program carried at the calibration system. As shown in fig. 2, the process may include the steps of:

step 202: acquiring target calibration data acquired by the mobile measurement system at a preset road section; the target calibration data are data acquired in the process that the vehicle with the mobile measurement system is respectively driven along a first direction and a second direction at the preset road section, and the second direction is opposite to the first direction.

In this embodiment of the present disclosure, the preset road section may be a pre-selected calibration road section, the preset road section may be selected according to actual requirements, and may be a certain road section on a city road or a certain road section on a country road, which is not specifically limited, and meanwhile, the length of the preset road section is not specifically limited.

In the embodiment of the present disclosure, the first direction and the second direction may be both the traveling direction of the vehicle on which the movement measurement system is mounted, and the first direction and the second direction may be opposite. In general, a vehicle is to travel along a road segment, and thus, the first direction and the second direction may generally be along directions of a preset segment. For example, if the starting point of a certain preset road section is a point a and the ending point is a point B, the first direction may be a direction from a to B, and the corresponding second direction is a direction from B to a; the opposite is also possible, i.e. the first direction may be the direction from B to a, and the corresponding second direction is the direction from a to B.

In the embodiment of the present specification, the mobile measurement system may include a lidar device, a global navigation satellite system, and an inertial navigation device. The mobile measurement system can be installed on a vehicle, and in the running process of the vehicle with the mobile measurement system, the mobile measurement system can collect point cloud data of objects around the vehicle, and position data and inertial navigation data of inertial navigation equipment. Correspondingly, the target calibration data may include point cloud data, position data of the inertial navigation device, and inertial navigation data. This will be further explained in the following embodiments, and will not be described here.

Step 204: and resolving point cloud data acquired by the laser radar equipment at the mobile measurement system in the target calibration data to obtain first coordinate data of a first position of a target object in the preset road section in a world coordinate system acquired along the first direction and second coordinate data of a second position of the target object in the preset road section in the world coordinate system acquired along the second direction.

In the embodiment of the present disclosure, the target object may be located in a preset road section, or may be located around the preset road section, which is not limited specifically. The target object may include: the wall surfaces of buildings around the preset road section, advertisement boards around the preset road section, road traffic marks drawn on the road surface of the preset road section, and the like. This will be further explained in the following embodiments, and will not be described here.

In the present description, the world coordinate system may be used to describe the position of an object in the real world. Specifically, the world coordinate system may be a geodetic coordinate system, or may be another coordinate system set according to actual requirements and used for describing the position of the object in the real world, which is not limited in particular. The geodetic coordinate system is a coordinate system established by taking a reference ellipsoid as a datum plane in geodetic measurement, and the position of any point in the geodetic coordinate system can be expressed by longitude, latitude and elevation. If the geodetic coordinate system is selected as the world coordinate system, the position data of the inertial navigation device collected by the global navigation satellite system at the preset road section may include longitude, latitude and elevation data of the inertial navigation device collected at each time point in the geodetic coordinate system.

Step 206: and taking the first position and the second position of the target object as adjustment targets, and adjusting the placement parameters of the laser radar according to the first coordinate data and the second coordinate data to obtain the placement parameters after calibration of the laser radar.

In the embodiment of the present specification, the placement parameters of the lidar may include: at least one of an X-direction rotation angle, a Y-direction rotation angle, a Z-direction rotation angle, an X-direction offset amount, a Y-direction offset amount and a Z-direction offset amount.

In the embodiment of the present specification, three coordinate systems are referred to as: the system comprises a radar coordinate system, an inertial navigation coordinate system and a world coordinate system, wherein the radar coordinate system can take a center point of laser radar equipment as a coordinate origin, and the radar coordinate system can take the center point of the inertial navigation equipment as the coordinate origin. The radar coordinate system and the inertial navigation coordinate system may be right-hand coordinate systems, for example, when the inertial navigation coordinate system is constructed, the installation platform of the mobile measurement system may be used as a reference horizontal plane, the center point of the inertial navigation device is used as an origin, the forward direction is used as a y-axis, the vertical upward direction is used as a z-axis, and the horizontal rightward direction is used as an x-axis. The radar coordinate system can be overlapped with the inertial navigation coordinate system through rotation and translation, and the rotation and translation parameters of the radar coordinate system relative to the inertial navigation coordinate system can correspond to 6 placement parameters of the laser radar.

In this embodiment of the present disclosure, the positioning parameters of the lidar may be adjusted according to the first coordinate data of the target object and the second coordinate data of the target object, so as to reduce a data difference between the first coordinate data and the second coordinate data, and iteratively adjust the positioning parameters of the lidar, or may also be used to draw a first position image of the target object and a second position image of the target object according to the first coordinate data of the target object and the second coordinate data of the target object, and then overlap the first position image and the second position image as adjustment targets, so as to adjust the positioning parameters of the lidar, which is not limited in particular. In addition, the execution subject for adjusting the laser radar setting parameters may be a calibration system, a program, or a person, which is not particularly limited.

Based on the method in fig. 2, the examples of the present specification also provide some specific embodiments of the method, as described below.

In the embodiment of the present specification, the target calibration data may include point cloud data, position data of the inertial navigation device, and inertial navigation data.

Based on this, in the method in fig. 2, in step 202, the acquiring the target calibration data acquired by the mobile measurement system at the preset road section may specifically include:

And acquiring point cloud data acquired by the laser radar equipment at the mobile measurement system at a preset road section.

And acquiring position data of the inertial navigation device acquired by the global navigation satellite system at the mobile measurement system at a preset road section.

Inertial navigation data acquired by the inertial navigation equipment at the mobile measurement system at a preset road section are acquired.

In the embodiment of the present specification, the lidar apparatus may be a radar system that detects a feature quantity such as a position, a shape, or the like of a target object with a laser beam emitted. The working principle of the laser radar device may be to transmit a detection signal (laser beam) to a target object, then compare a received signal (target echo) reflected from the target object with the transmission signal, and perform appropriate processing to obtain relevant information (such as parameters including target distance, azimuth, altitude, shape, etc.) of the target object, and continuously scan the target object by using pulse laser to obtain point cloud data of all target points on the target object, and perform imaging processing by using the point cloud data to obtain an accurate three-dimensional stereo image. The laser radar device may be composed of a laser transmitter, an optical receiver, a turntable, an information processing system, and the like, wherein the laser transmitter may transmit the electric pulse into an optical pulse, and the optical receiver may restore the optical pulse reflected from the target into the electric pulse.

In the embodiment of the present disclosure, a Global Navigation Satellite System (GNSS) may refer to all global satellite navigation systems, such as GPS in the united states, GLONASS in russia, beidou satellite navigation system in china, galileo in the european union, and so on. The global navigation satellite system can provide the user with space-based radio navigation positioning services of all-weather three-dimensional coordinates (longitude, latitude and elevation), speed and time information at any place on the earth's surface or in the near-earth space. The position data of the inertial navigation device acquired by the global navigation satellite system at the preset road section may include three-dimensional coordinate data of the inertial navigation device acquired at each point in time in the world coordinate system.

In practical applications, the inertial navigation device may use an IMU (inertial measurement unit), which may be a device for measuring three-axis attitude angles (including pitch angle, roll angle, and heading angle) and accelerations of an object. Typically, an IMU may include three single-axis accelerometers and three single-axis gyroscopes, where the accelerometers may detect acceleration signals of the object and the gyroscopes may detect angular velocity signals of the object, measure angular velocity and acceleration of the object in three-dimensional space, and calculate the pose of the object based on the angular velocity and acceleration. Inertial navigation data acquired by the inertial navigation device at a preset road segment may include attitude angles (including pitch angle, roll angle, and heading angle) of the inertial navigation device itself acquired at various points in time with respect to a world coordinate system.

Correspondingly, in the method in fig. 2, in step 204, the calculating the point cloud data collected by the lidar device at the mobile measurement system in the target calibration data to obtain first coordinate data of a first position of the target object in the preset road section in the world coordinate system collected along the first direction and second coordinate data of a second position of the target object in the preset road section in the world coordinate system collected along the second direction may specifically include:

according to the position data of the inertial navigation device and the inertial navigation data, the point cloud data are calculated to obtain first coordinate data of a first position of a target object in the preset road section in a world coordinate system, which is acquired along the first direction, and second coordinate data of a second position of the target object in the preset road section in the world coordinate system, which is acquired along the second direction.

In this embodiment of the present disclosure, the position data and the inertial navigation data of the inertial navigation device in the target calibration data may be used to calculate the point cloud data in the target calibration data, so as to obtain first coordinate data of a first position of the target object in the preset road section in the world coordinate system acquired along the first direction, and second coordinate data of a second position of the target object in the preset road section in the world coordinate system acquired along the second direction.

In the embodiment of the present disclosure, when the vehicle travels at the preset road section along the first direction, the lidar device may collect the point cloud data once for the target object; the laser radar device may collect second time point cloud data for the target object while the vehicle is traveling in the second direction at the preset road section.

Based on this, the point cloud data may include: first point cloud data and second point cloud data; the first point cloud data is data acquired by the laser radar device for the target object in the process that the vehicle runs along the first direction at the preset road section; the second point cloud data is data acquired by the laser radar device for the target object in the process that the vehicle runs along the second direction at the preset road section.

Correspondingly, the calculating the point cloud data according to the position data of the inertial navigation device and the inertial navigation data to obtain first coordinate data of a first position of the target object in the preset road section in the world coordinate system acquired along the first direction and second coordinate data of a second position of the target object in the preset road section in the world coordinate system acquired along the second direction may specifically include:

And determining the conversion relation between the inertial navigation coordinate system at the inertial navigation equipment and the world coordinate system according to the position data of the inertial navigation equipment and the inertial navigation data.

And determining third coordinate data of the first point cloud data in the inertial navigation coordinate system according to the initial placement parameters of the laser radar.

And determining the first coordinate data in the world coordinate system corresponding to the third coordinate data by utilizing the conversion relation between the inertial navigation coordinate system and the world coordinate system.

And determining fourth coordinate data of the second point cloud data in the inertial navigation coordinate system according to the initial placement parameters of the laser radar.

And determining the second coordinate data in the world coordinate system corresponding to the fourth coordinate data by utilizing the conversion relation between the inertial navigation coordinate system and the world coordinate system.

In the embodiment of the present disclosure, the process of resolving the point cloud data may be a process of converting the point cloud data in the radar coordinate system into coordinate data in the inertial navigation coordinate system according to a conversion relationship between the radar coordinate system and the inertial navigation coordinate system, and further converting the coordinate data in the inertial navigation coordinate system into coordinate data in the world coordinate system according to a conversion relationship between the inertial navigation coordinate system and the world coordinate system.

In the embodiment of the present specification, the position data of the inertial navigation device may correspond to three-dimensional position coordinates of the origin of coordinates of the inertial navigation coordinate system in the world coordinate system. The inertial navigation data may include attitude angles (including pitch angle, roll angle and heading angle) of the inertial navigation device itself with respect to the world coordinate system acquired at various points in time, and thus the inertial navigation data may correspond to rotation angles of three coordinate axes of the inertial navigation coordinate system with respect to three coordinate axes of the world coordinate system. Therefore, the conversion relation between the inertial navigation coordinate system and the world coordinate system can be determined according to the position data and the inertial navigation data of the inertial navigation equipment.

In the embodiment of the present disclosure, the initial placement parameters of the lidar may be obtained through a structural drawing of the lidar, or may be obtained in other manners, or the initial placement parameters of the lidar may be set to 0, which is not specifically limited. The placement parameters of the lidar may correspond to a conversion relationship between the radar coordinate system and the inertial navigation coordinate system, and therefore, coordinate data of the point cloud data in the inertial navigation coordinate system at the inertial navigation device may be preliminarily determined according to the initial placement parameters of the lidar. After the subsequent adjustment of the laser radar placement parameters, the coordinate data of the point cloud data in the inertial navigation coordinate system can be correspondingly changed.

In the embodiment of the present disclosure, the target objects may be classified into different types, for example, when the target object is a pattern drawn on a surface of a preset road section, the target object may be classified into a first type; when the included angle between the target object and the preset road section is smaller than the target surface of the first threshold value, the target object can be divided into a second type; and when the target object is a target surface with an included angle with the preset road section being larger than a second threshold value, the target object can be classified into a third type. When adjusting the placement parameters of the laser radar, the type of the target object needs to be determined first, and then different placement parameters of the laser radar can be correspondingly adjusted according to the type of the target object.

Based on this, in the method in fig. 2, in step 206, the adjusting the positioning parameters of the lidar by using the first position and the second position of the target object as adjustment targets and according to the first coordinate data and the second coordinate data, to obtain the calibrated positioning parameters of the lidar may specifically include:

if the target object is of a first type, the first position and the second position of the target object are overlapped to be an adjustment target, and according to the first coordinate data and the second coordinate data, the X-direction offset and the Y-direction offset in the placement parameters of the laser radar are adjusted to obtain the X-direction offset and the Y-direction offset in the placement parameters after the calibration of the laser radar; the first type is used for indicating that the target object is a pattern drawn on the surface of the preset road section.

If the target object is of a second type, the first position and the second position of the target object are overlapped to be an adjustment target, and the Y-direction rotation angle and the Z-direction rotation angle in the placement parameters of the laser radar are adjusted according to the first coordinate data and the second coordinate data to obtain the Y-direction rotation angle and the Z-direction rotation angle in the placement parameters after calibration of the laser radar; the second type is used for indicating that the target object is a target surface with an included angle with the preset road section smaller than a first threshold value.

If the target object is of a third type, the first position and the second position of the target object are overlapped to be an adjustment target, and according to the first coordinate data and the second coordinate data, the X-direction rotation angle in the placement parameters of the laser radar is adjusted to obtain the X-direction rotation angle in the placement parameters after calibration of the laser radar; the third type is used for indicating that the target object is a target surface with an included angle between the target object and the preset road section being larger than a second threshold value.

In the embodiment of the present disclosure, if the target object is of the first type, the target object may be considered to be located in a plane where a surface of a preset road section is located, so that the first position and the second position of the target object may be overlapped to be an adjustment target, and according to the first coordinate data and the second coordinate data, an X-direction offset and a Y-direction offset in a placement parameter of the laser radar may be adjusted; if the target object is of the second type, the target object can be approximately considered to be positioned in a plane parallel to the direction of the preset road section, so that the first position and the second position of the target object can be overlapped to be an adjustment target, and the Y-direction rotation angle and the Z-direction rotation angle in the placement parameters of the laser radar can be adjusted according to the first coordinate data and the second coordinate data; if the target object is of the third type, the target object can be approximately considered to be located in a plane perpendicular to the preset road section direction, so that the first position and the second position of the target object can be overlapped to be an adjustment target, and the X-direction rotation angle in the placement parameters of the laser radar can be adjusted according to the first coordinate data and the second coordinate data.

In the embodiment of the present disclosure, a smaller angle between the target object and the preset road section may be used as the included angle between the target object and the preset road section, so the included angle between the target object and the preset road section may not exceed 90 degrees. The first threshold and the second threshold can be set according to actual demands, the first threshold and the second threshold can not exceed 90 degrees, and specific values of the first threshold and the second threshold are not limited specifically. Typically, the first threshold is much smaller than the second threshold. For example, a first threshold is set to be 10 degrees, a second threshold is set to be 80 degrees, and if the included angle between the target object and the preset road section is smaller than 10 degrees, the target object is classified into a second type; and if the included angle between the target object and the preset road section is larger than 80 degrees, dividing the target object into a third type.

Specifically, if the target object is of the first type, the target object includes a road traffic marking.

And if the target object is of the second type, the target object comprises a first wall surface.

If the target object is of a third type, the target object comprises a second wall surface; the first wall surface and the second wall surface are different walls at the same building, or the first wall surface and the second wall surface are different walls at different buildings.

In practical application, road traffic markings are usually drawn on a preset road section, so that part of road traffic markings drawn on the preset road section can be used as a first type of target object for data acquisition, namely, point cloud data of part of road traffic markings are acquired by using laser radar equipment.

In practical application, a plurality of regular-shaped buildings are arranged around the preset road section, so that the wall surfaces approximately parallel to the preset road section direction in the wall surfaces of the buildings can be selected as a first wall surface, and the wall surfaces approximately perpendicular to the preset road section direction in the wall surfaces of the buildings can be selected as a second wall surface. The first wall surface and the second wall surface may belong to the same building, or may belong to different buildings, which is not particularly limited.

In practical application, the target object aimed at by the point cloud data acquisition can be a road traffic marking or a characteristic wall surface, and compared with a control point, the range of the road traffic marking or the characteristic wall surface for receiving detection signals (laser beams) sent by the laser radar is larger, so that the laser radar has smaller point frequency limit, and the calibration precision of the laser radar placement parameters and the application range of the point cloud data acquisition are improved.

In the embodiment of the present disclosure, according to three types of target objects, the positioning parameters of the lidar may be adjusted correspondingly: regarding the Z-direction offset in the setting parameters, the preset control point can be used as a target object to collect point cloud data, and then the Z-direction offset in the setting parameters is determined according to the difference value between the elevation data of the preset control point in the world coordinate system and the known elevation data of the preset control point after the calculation of the point cloud data.

Based on this, in step 204, after the calculating the point cloud data collected by the lidar device at the mobile measurement system in the target calibration data to obtain the first coordinate data of the first position of the target object in the preset road segment in the world coordinate system collected along the first direction and the second coordinate data of the second position of the target object in the preset road segment in the world coordinate system collected along the second direction, the method in fig. 2 may further include:

Acquiring the first coordinate data and the second coordinate data corresponding to target point cloud data in the point cloud data; the target point cloud data are the point cloud data acquired for a preset control point.

And acquiring calibrated elevation data of the preset control point in the world coordinate system.

And calculating the average value of the elevation data in the first coordinate data corresponding to the target point cloud data and the elevation data in the second coordinate data corresponding to the target point cloud data to obtain the elevation data of the preset control point.

And determining the Z-direction offset in the calibrated setting parameters of the laser radar according to the difference value between the elevation data of the preset control point and the calibrated elevation data.

In the embodiment of the present disclosure, the preset control point may be a control point that measures three-dimensional coordinates thereof in a world coordinate system in advance using a precise measuring instrument. The preset control point may be located on a road surface of the preset road section, or may be located around the preset road section, which is not particularly limited. The preset control points may be set only one or a plurality of control points, which is not particularly limited.

In this embodiment of the present disclosure, the calibrated elevation data may be elevation data of a preset control point in a world coordinate system, which is measured by a precise measuring instrument in advance. The elevation data in the first coordinate data and the elevation data in the second coordinate data may be the same or different, when the two data are the same, the elevation data may be used as elevation data of a preset control point, and when the two data are different, the average value of the two data may be used as elevation data of the preset control point.

In the method in fig. 2, after the calibration system acquires the target calibration data acquired by the mobile measurement system at the preset road section, the point cloud data in the target calibration data are resolved to obtain first coordinate data and second coordinate data of the target object, and then the positioning parameters of the laser radar at the mobile measurement system are adjusted according to the first coordinate data and the second coordinate data of the target object, so that the post-calibration positioning parameters of the laser radar are finally obtained. Based on the scheme of the invention, a professional calibration field is not required to be established in advance, thereby being beneficial to reducing the cost of calibrating the laser radar setting parameters and improving the calibration efficiency and accuracy of the laser radar setting parameters.

In addition, in the method in fig. 2, the target object aimed at by the point cloud data collection may be a feature plane, instead of the conventional calibration by using a control point, so that the laser radar has smaller point frequency limitation, and the method can be suitable for the target object farther from the laser radar, thereby being beneficial to improving the calibration precision of the laser radar placement parameters and the application range of the calibration scheme.

Based on the same thought, the embodiment of the specification also provides a device corresponding to the method. Fig. 3 is a schematic structural diagram of a calibration device of the mobile measurement system corresponding to fig. 2 according to an embodiment of the present disclosure. As shown in fig. 3, the apparatus may include:

The present description example also provides some specific embodiments of the device based on the device of fig. 3, which is described below.

Alternatively, the mobile measurement system may comprise a lidar device, a global navigation satellite system, and an inertial navigation device.

Correspondingly, the first obtaining module may specifically include:

the first acquisition unit is used for acquiring point cloud data acquired by the laser radar equipment at the mobile measurement system at a preset road section.

And the second acquisition unit is used for acquiring the position data of the inertial navigation device acquired by the global navigation satellite system at the mobile measurement system at a preset road section.

And the third acquisition unit is used for acquiring inertial navigation data acquired by the inertial navigation equipment at the mobile measurement system at a preset road section.

Correspondingly, the resolving module may specifically include:

the calculating unit is used for calculating the point cloud data according to the position data of the inertial navigation device and the inertial navigation data to obtain first coordinate data of a first position of a target object in the preset road section in a world coordinate system acquired along the first direction and second coordinate data of a second position of the target object in the preset road section in the world coordinate system acquired along the second direction.

Optionally, the point cloud data may include: first point cloud data and second point cloud data; the first point cloud data is data acquired by the laser radar device for the target object in the process that the vehicle runs along the first direction at the preset road section; the second point cloud data is data acquired by the laser radar device for the target object in the process that the vehicle runs along the second direction at the preset road section.

Correspondingly, the resolving unit may specifically include:

and the first determination subunit is used for determining the conversion relation between the inertial navigation coordinate system at the inertial navigation equipment and the world coordinate system according to the position data of the inertial navigation equipment and the inertial navigation data.

And the second determining subunit is used for determining third coordinate data of the first point cloud data in the inertial navigation coordinate system according to the initial placement parameters of the laser radar.

And a third determination subunit configured to determine the first coordinate data in the world coordinate system corresponding to the third coordinate data, using a conversion relationship between the inertial navigation coordinate system and the world coordinate system.

And the fourth determining subunit is used for determining fourth coordinate data of the second point cloud data in the inertial navigation coordinate system according to the initial placement parameters of the laser radar.

And a fifth determination subunit configured to determine the second coordinate data in the world coordinate system corresponding to the fourth coordinate data, using a conversion relationship between the inertial navigation coordinate system and the world coordinate system.

Optionally, the adjusting module may specifically include:

the first adjusting unit is used for adjusting the X-direction offset and the Y-direction offset in the placement parameters of the laser radar according to the first coordinate data and the second coordinate data by taking the superposition of the first position and the second position of the target object as an adjusting target if the target object is of a first type, so as to obtain the X-direction offset and the Y-direction offset in the placement parameters after calibration of the laser radar; the first type is used for indicating that the target object is a pattern drawn on the surface of the preset road section.

The second adjusting unit is used for adjusting the Y-direction rotation angle and the Z-direction rotation angle in the placement parameters of the laser radar according to the first coordinate data and the second coordinate data by taking the superposition of the first position and the second position of the target object as an adjusting target if the target object is of a second type, so as to obtain the Y-direction rotation angle and the Z-direction rotation angle in the placement parameters after calibration of the laser radar; the second type is used for indicating that the target object is a target surface with an included angle with the preset road section smaller than a first threshold value.

The third adjusting unit is used for adjusting the X-direction rotation angle in the placement parameters of the laser radar according to the first coordinate data and the second coordinate data by taking the superposition of the first position and the second position of the target object as an adjusting target if the target object is of a third type, so as to obtain the X-direction rotation angle in the placement parameters after the calibration of the laser radar; the third type is used for indicating that the target object is a target surface with an included angle between the target object and the preset road section being larger than a second threshold value.

Optionally, the apparatus may further include:

the second acquisition module is used for acquiring the first coordinate data and the second coordinate data corresponding to the target point cloud data in the point cloud data; the target point cloud data are the point cloud data acquired for a preset control point.

And the third acquisition module is used for acquiring the calibrated elevation data of the preset control point in the world coordinate system.

The calculation module is used for calculating the average value of the elevation data in the first coordinate data corresponding to the target point cloud data and the elevation data in the second coordinate data corresponding to the target point cloud data to obtain the elevation data of the preset control point.

And the Z-direction offset determining module is used for determining the Z-direction offset in the calibrated setting parameters of the laser radar according to the difference value between the elevation data of the preset control point and the calibrated elevation data.

Based on the same thought, the embodiment of the specification also provides equipment corresponding to the method.

Fig. 4 is a schematic structural diagram of a calibration device of the mobile measurement system corresponding to fig. 2 according to an embodiment of the present disclosure. As shown in fig. 4, the apparatus 400 may include:

at least one processor 410; the method comprises the steps of,

a memory 430 communicatively coupled to the at least one processor; wherein,,

the memory 430 stores instructions 420 executable by the at least one processor 410, the instructions being executable by the at least one processor 410 to enable the at least one processor 410 to:

In this specification, each embodiment is described in a progressive manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments. In particular, for the apparatus shown in fig. 4, the description is relatively simple, as it is substantially similar to the method embodiment, with reference to the partial description of the method embodiment.

In the 90 s of the 20 th century, improvements to one technology could clearly be distinguished as improvements in hardware (e.g., improvements to circuit structures such as diodes, transistors, switches, etc.) or software (improvements to the process flow). However, with the development of technology, many improvements of the current method flows can be regarded as direct improvements of hardware circuit structures. Designers almost always obtain corresponding hardware circuit structures by programming improved method flows into hardware circuits. Therefore, an improvement of a method flow cannot be said to be realized by a hardware entity module. For example, a Programmable logic device (Programmable LogicDevice, PLD), such as a field Programmable gate array (FieldProgrammableGateArray, FPGA), is an integrated circuit whose logic function is determined by the programming of the device by a user. A designer programs to "integrate" a digital system onto a PLD without requiring the chip manufacturer to design and fabricate application-specific integrated circuit chips. Moreover, nowadays, instead of manually manufacturing integrated circuit chips, such programming is mostly implemented by using "logic compiler" software, which is similar to the software compiler used in program development and writing, and the original code before the compiling is also written in a specific programming language, which is called hardware description language (HardwareDescription Language, HDL), but HDL is not just one, but a plurality of kinds, such as ABEL (Advanced BooleanExpressionLanguage), AHDL (AlteraHardwareDescriptionLanguage), confluence, CUPL (cornellunignyiProgrammingLangage), HDcal, jHDL (javahard script language), lava, lola, myHDL, PALASM, RHDL (rubyHardwareDescriptionLangLange) and the like, and VHDL (Very-High-speededdie hard script DescriptionLange) and Verilog are most commonly used at present. It will also be apparent to those skilled in the art that a hardware circuit implementing the logic method flow can be readily obtained by merely slightly programming the method flow into an integrated circuit using several of the hardware description languages described above.

The controller may be implemented in any suitable manner, for example, the controller may take the form of, for example, a microprocessor or processor and a computer readable medium storing computer readable program code (e.g., software or firmware) executable by the (micro) processor, logic gates, switches, application specific integrated circuits (application specific IntegratedCircuit, ASIC), programmable logic controllers, and embedded microcontrollers, examples of controllers include, but are not limited to, the following microcontrollers: ARC625D, atmelAT91SAM, microchip PIC18F26K20, and silicalabsc 8051F320, the memory controller may also be implemented as part of the control logic of the memory. Those skilled in the art will also appreciate that, in addition to implementing the controller in a pure computer readable program code, it is well possible to implement the same functionality by logically programming the method steps such that the controller is in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers, etc. Such a controller may thus be regarded as a kind of hardware component, and means for performing various functions included therein may also be regarded as structures within the hardware component. Or even means for achieving the various functions may be regarded as either software modules implementing the methods or structures within hardware components.

The system, apparatus, module or unit set forth in the above embodiments may be implemented in particular by a computer chip or entity, or by a product having a certain function. One typical implementation is a computer. In particular, the computer may be, for example, a personal computer, a laptop computer, a cellular telephone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

For convenience of description, the above devices are described as being functionally divided into various units, respectively. Of course, the functions of each element may be implemented in one or more software and/or hardware elements when implemented in the present specification.

It will be appreciated by those skilled in the art that 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 an entirely hardware embodiment, an entirely 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, CD-ROM, 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 flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations 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.

In one typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

The memory may include volatile memory in a computer-readable medium, random Access Memory (RAM) and/or nonvolatile memory, etc., such as Read Only Memory (ROM) or flash memory (flashRAM). Memory is an example of computer-readable media.

Computer readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of storage media for a computer include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device. Computer-readable media, as defined herein, does not include transitory computer-readable media (transshipment) such as modulated data signals and carrier waves.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises the element.

The description may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The specification may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.

The foregoing is merely exemplary of the present disclosure and is not intended to limit the disclosure. Various modifications and alterations to this specification will become apparent to those skilled in the art. Any modifications, equivalent substitutions, improvements, or the like, which are within the spirit and principles of the present description, are intended to be included within the scope of the claims of the present description.

Claims

1. A method for calibrating a mobile measurement system, the method comprising:

acquiring target calibration data acquired by the mobile measurement system at a preset road section; the target calibration data are data acquired in the process that a vehicle with the mobile measurement system runs along a first direction and a second direction at the preset road section respectively, and the second direction is opposite to the first direction;

resolving point cloud data acquired by laser radar equipment at the mobile measurement system in the target calibration data to obtain first coordinate data of a first position of a target object in the preset road section in a world coordinate system acquired along the first direction and second coordinate data of a second position of the target object in the preset road section in the world coordinate system acquired along the second direction;

2. The method of claim 1, wherein the mobile measurement system comprises a lidar device, a global navigation satellite system, and an inertial navigation device;

the obtaining the target calibration data collected by the mobile measurement system at the preset road section specifically comprises the following steps:

acquiring point cloud data acquired by the laser radar equipment at a preset road section at the mobile measurement system;

acquiring position data of the inertial navigation device acquired by the global navigation satellite system at a preset road section at the mobile measurement system;

acquiring inertial navigation data acquired by the inertial navigation equipment at the mobile measurement system at a preset road section;

the calculating the point cloud data collected by the laser radar device at the mobile measurement system in the target calibration data to obtain first coordinate data of a first position of a target object in the preset road section in a world coordinate system collected along the first direction and second coordinate data of a second position of the target object in the preset road section in the world coordinate system collected along the second direction specifically includes:

3. The method of claim 2, wherein the point cloud data comprises: first point cloud data and second point cloud data; the first point cloud data is data acquired by the laser radar device for the target object in the process that the vehicle runs along the first direction at the preset road section; the second point cloud data is data acquired by the laser radar device for the target object in the process that the vehicle runs along the second direction at the preset road section;

the calculating the point cloud data according to the position data of the inertial navigation device and the inertial navigation data to obtain first coordinate data of a first position of a target object in the preset road section in a world coordinate system acquired along the first direction and second coordinate data of a second position of the target object in the preset road section in the world coordinate system acquired along the second direction, specifically includes:

Determining a conversion relation between an inertial navigation coordinate system at the inertial navigation device and a world coordinate system according to the position data of the inertial navigation device and the inertial navigation data;

determining third coordinate data of the first point cloud data in the inertial navigation coordinate system according to initial placement parameters of the laser radar;

determining the first coordinate data in the world coordinate system corresponding to the third coordinate data by utilizing a conversion relation between the inertial navigation coordinate system and the world coordinate system;

determining fourth coordinate data of the second point cloud data in the inertial navigation coordinate system according to initial placement parameters of the laser radar;

4. The method according to claim 1, wherein the adjusting the positioning parameters of the lidar to obtain the calibrated positioning parameters of the lidar by using the first position and the second position of the target object as adjustment targets and according to the first coordinate data and the second coordinate data specifically comprises:

If the target object is of a first type, the first position and the second position of the target object are overlapped to be an adjustment target, and according to the first coordinate data and the second coordinate data, the X-direction offset and the Y-direction offset in the placement parameters of the laser radar are adjusted to obtain the X-direction offset and the Y-direction offset in the placement parameters after the calibration of the laser radar; the first type is used for representing that the target object is a pattern drawn on the surface of the preset road section;

if the target object is of a second type, the first position and the second position of the target object are overlapped to be an adjustment target, and the Y-direction rotation angle and the Z-direction rotation angle in the placement parameters of the laser radar are adjusted according to the first coordinate data and the second coordinate data to obtain the Y-direction rotation angle and the Z-direction rotation angle in the placement parameters after calibration of the laser radar; the second type is used for indicating that the target object is a target surface with an included angle with the preset road section smaller than a first threshold value;

5. The method of claim 4, wherein if the target object is of a first type, the target object comprises a road traffic marking;

if the target object is of the second type, the target object comprises a first wall surface;

6. The method according to claim 1, wherein the calculating the point cloud data collected by the lidar device at the mobile measurement system in the target calibration data, to obtain first coordinate data of a first location in a world coordinate system where the target object in the preset road segment collected along the first direction is located, and second coordinate data of a second location in the world coordinate system where the target object in the preset road segment collected along the second direction is located, further includes:

acquiring the first coordinate data and the second coordinate data corresponding to target point cloud data in the point cloud data; the target point cloud data are the point cloud data acquired for a preset control point;

Acquiring calibrated elevation data of the preset control point in the world coordinate system;

calculating the average value of the elevation data in the first coordinate data corresponding to the target point cloud data and the elevation data in the second coordinate data corresponding to the target point cloud data to obtain the elevation data of the preset control point;

7. A mobile measurement system calibration device, the device comprising:

the first acquisition module is used for acquiring target calibration data acquired by the mobile measurement system at a preset road section; the target calibration data are data acquired in the process that a vehicle with the mobile measurement system runs along a first direction and a second direction at the preset road section respectively, and the second direction is opposite to the first direction;

the calculation module is used for calculating point cloud data acquired by the laser radar equipment at the mobile measurement system in the target calibration data to obtain first coordinate data of a first position of a target object in the preset road section in a world coordinate system acquired along the first direction and second coordinate data of a second position of the target object in the preset road section in the world coordinate system acquired along the second direction;

8. The device according to claim 7, characterized in that said adjustment module comprises in particular:

the first adjusting unit is used for adjusting the X-direction offset and the Y-direction offset in the placement parameters of the laser radar according to the first coordinate data and the second coordinate data by taking the superposition of the first position and the second position of the target object as an adjusting target if the target object is of a first type, so as to obtain the X-direction offset and the Y-direction offset in the placement parameters after calibration of the laser radar; the first type is used for representing that the target object is a pattern drawn on the surface of the preset road section;

the second adjusting unit is used for adjusting the Y-direction rotation angle and the Z-direction rotation angle in the placement parameters of the laser radar according to the first coordinate data and the second coordinate data by taking the superposition of the first position and the second position of the target object as an adjusting target if the target object is of a second type, so as to obtain the Y-direction rotation angle and the Z-direction rotation angle in the placement parameters after calibration of the laser radar; the second type is used for indicating that the target object is a target surface with an included angle with the preset road section smaller than a first threshold value;

9. The apparatus of claim 7, wherein the apparatus further comprises:

the second acquisition module is used for acquiring the first coordinate data and the second coordinate data corresponding to the target point cloud data in the point cloud data; the target point cloud data are the point cloud data acquired for a preset control point;

the third acquisition module is used for acquiring calibrated elevation data of the preset control point in the world coordinate system;

the calculation module is used for calculating the average value of the elevation data in the first coordinate data corresponding to the target point cloud data and the elevation data in the second coordinate data corresponding to the target point cloud data to obtain the elevation data of the preset control point;

10. A mobile measurement system calibration apparatus, the apparatus comprising:

at least one processor; the method comprises the steps of,

a memory communicatively coupled to the at least one processor; wherein,,