Object perimeter measurement method and device, computer equipment and storage medium

Abstract

The invention relates to the technical field of laser radar surveying and mapping, and discloses an object perimeter measurement method and device, computer equipment and a storage medium, and the method comprises the steps: sequentially obtaining timestamps, laser scanning data and radar pose data when all feature points on a to-be-measured object are scanned through a single-line laser radar; according to a timestamp sequence, mapping the laser scanning data of each feature point into a polar coordinate system to obtain first peripheral shape point cloud data; establishing a rectangular coordinate system, and converting the first peripheral shape point cloud data into second peripheral shape point cloud data in the rectangular coordinate system; performing timestamp-by-timestamp data fusion on the radar pose data and the second peripheral shape point cloud data to obtain third peripheral shape point cloud data; generating a curvilinear function according to the third peripheral shape point cloud data; and calculating the length corresponding to the curvilinear function as the object perimeter of the to-be-measured object. The method realizes accurate calculation of the perimeter of the object, and has the advantages of non-contact, high precision, high efficiency and the like.

Description

Technical Field

[0001] The present invention relates to the field of laser radar surveying and mapping technology, and in particular to a method, device, computer equipment and storage medium for measuring the circumference of an object. Background Art

[0002] As an advanced active remote sensing technology, LiDAR (Light Detection and Ranging) has shown great application potential in the field of modern measurement and perception. Its working principle is based on emitting laser pulses and accurately measuring the time from the emission to the reflection of these pulses by the target object, thereby calculating the distance to the target object.

[0003] In the field of precision measurement, traditional measurement methods often require direct contact with the target object, which may not only damage the surface structure of the object being measured, but also cause measurement errors due to improper human operation. In the medical field, traditional methods often require the use of rulers, tape measures and other tools to measure patients' physical data, which is not only cumbersome to operate, but may also lead to inaccurate measurement results due to patient discomfort or cooperation problems. In addition, in special environments (such as high temperature, high pressure, toxic, harmful, etc.), the measurement of an object's data often faces great challenges. Traditional measurement methods are not only difficult to operate, but may also pose a safety hazard to measurement personnel. LiDAR technology, with its remote and non-contact measurement characteristics, can achieve safe and accurate measurements in these special environments.

[0004] However, most of the existing lidar technologies are based on fixed installation or multi-line scanning, which can measure the distance to the target object, but it is difficult to measure the circumference of the object, especially for objects with complex shapes and irregular surfaces, it is often difficult to obtain accurate circumference data. Summary of the invention

[0005] Based on this, it is necessary to address the problem that the circumference of objects with complex shapes or irregular surfaces is difficult to measure accurately, and a method, device, computer equipment and storage medium for measuring the circumference of an object are proposed.

[0006] A first aspect of the present invention provides a method for measuring the circumference of an object, the method comprising:

[0007] Sequentially obtain the timestamp when each feature point on the object to be measured is scanned by a pre-deployed single-line laser radar, the laser scanning data at the timestamp, and the radar posture data at the timestamp;

[0008] Mapping the laser scanning data of each feature point into a polar coordinate system in a timestamp order to obtain first peripheral shape point cloud data of the object to be measured in the polar coordinate system;

[0009] Establishing a rectangular coordinate system, converting the first peripheral shape point cloud data into second peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0010] The radar posture data at each time stamp is fused with the second peripheral shape point cloud data on a time stamp basis to obtain third peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0011] Generating a curve function for describing the peripheral shape characteristics of the object to be measured according to the third peripheral shape point cloud data;

[0012] The length corresponding to the curve function is calculated, and the length is used as the object circumference of the object to be measured.

[0013] Furthermore, the step of sequentially acquiring the timestamp when each feature point on the object to be measured is scanned by a pre-deployed single-line laser radar, the laser scanning data at the timestamp, and the radar pose data at the timestamp includes:

[0014] A scanning laser beam is emitted to the object to be measured through a pre-deployed single-line laser radar;

[0015] When receiving the reflected light signal after the scanning laser beam reaches the current feature point on the object to be measured, the current time is recorded as a timestamp, and the position and yaw angle of the single-line laser radar under the timestamp are recorded, and the position and yaw angle are used as radar posture data;

[0016] Analyze the reflected light signal to obtain the angle and distance corresponding to the current feature point, and use the angle and distance as the laser scanning data, wherein the angle is the angle between the reflected light of the current feature point and the predefined reference direction of the single-line laser radar, and the distance is the distance between the current feature point and the single-line laser radar;

[0017] Adjust the emission direction of the scanning laser beam of the single-line laser radar and the relative position of the object to be measured, and perform the step of emitting the scanning laser beam to the object to be measured by the pre-deployed single-line laser radar again.

[0018] Furthermore, the laser scanning data includes angles and distances, and the step of mapping the laser scanning data of each feature point to a polar coordinate system in a timestamp order to obtain first peripheral shape point cloud data of the object to be measured in the polar coordinate system includes:

[0019] Establish polar coordinate system;

[0020] The angle corresponding to each timestamp is taken as the polar angle, the distance corresponding to each timestamp is taken as the polar diameter, and a group of polar angles and polar diameters corresponding to a timestamp is taken as a group of ordered number pairs. The ordered number pairs corresponding to each of the timestamps are plotted one by one in the polar coordinate system to obtain the first peripheral shape point cloud data of the object to be measured in the polar coordinate system.

[0021] Furthermore, the step of fusing the radar pose data at each time stamp with the second peripheral shape point cloud data to obtain the third peripheral shape point cloud data of the object to be measured in the rectangular coordinate system includes:

[0022] The position and yaw angle in the radar posture data corresponding to the first timestamp are used as the initial position and initial yaw angle respectively;

[0023] Calculate the position difference between the position in the radar pose data corresponding to each time stamp except the first time stamp and the initial position, and the yaw angle difference between the yaw angle in the radar pose data corresponding to each time stamp except the first time stamp and the initial yaw angle;

[0024] The position difference and the yaw angle difference corresponding to each timestamp are used to fuse and correct the rectangular coordinates of the corresponding timestamps in the second peripheral shape point cloud data to obtain the fused coordinate data corresponding to each timestamp, and the collection of each fused coordinate data corresponding to each timestamp is used as the third peripheral shape point cloud data.

[0025] Furthermore, the step of using the position difference and the yaw angle difference corresponding to each time stamp to fuse and correct the rectangular coordinates of the corresponding time stamp in the second peripheral shape point cloud data to obtain the fused coordinate data corresponding to each time stamp adopts the formula:

[0026] θ=yaw k -yaw0

[0027] Among them, (X k ,Y k ) is the rectangular coordinate of the point corresponding to the kth timestamp in the rectangular coordinate system; is the position of the single-line laser radar corresponding to the kth timestamp, and the initial position is set to is (0, 0); θ is the yaw angle difference, yaw0 is the initial yaw angle, yaw k is the yaw angle of the single-line lidar corresponding to the k-th timestamp.

[0028] Furthermore, the step of generating a curve function for describing the peripheral shape characteristics of the object to be measured according to the third peripheral shape point cloud data comprises:

[0029] Preprocessing the third peripheral shape point cloud data to obtain preprocessed point cloud data, wherein the preprocessing includes at least one of conditional filtering, noise removal, and resampling;

[0030] The pre-processed point cloud data is subjected to curve fitting using a cubic B-spline curve to obtain a curve function for describing the peripheral shape characteristics of the object to be measured.

[0031] Furthermore, the step of calculating the length corresponding to the curve function and taking the length as the circumference of the object to be measured includes:

[0032] Dividing the entire interval of the curve function into a plurality of subintervals;

[0033] In each of the subintervals, the Simpson formula is used to perform integration and calculate the curve length of each subinterval;

[0034] The curve lengths of the sub-intervals are added together to obtain a length corresponding to the curve function, and the length is used as the object circumference of the object to be measured.

[0035] A second aspect of the present invention provides a device for measuring the circumference of an object, the device comprising:

[0036] A data acquisition module is used to sequentially acquire the timestamp when each feature point on the object to be measured is scanned by a pre-deployed single-line laser radar, the laser scanning data at the timestamp, and the radar posture data at the timestamp;

[0037] A first point cloud data generating module, used for mapping the laser scanning data of each feature point into a polar coordinate system according to a timestamp sequence, to obtain first peripheral shape point cloud data of the object to be measured in the polar coordinate system;

[0038] A second point cloud data generating module is used to establish a rectangular coordinate system and convert the first peripheral shape point cloud data into second peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0039] A third point cloud data generating module is used to perform data fusion on a timestamp-by-timestamp basis on the radar posture data at each timestamp and the second peripheral shape point cloud data to obtain third peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0040] A curve function generating module, used for generating a curve function for describing the peripheral shape characteristics of the object to be measured according to the third peripheral shape point cloud data;

[0041] The object perimeter calculation module is used to calculate the length corresponding to the curve function and use the length as the object perimeter of the object to be measured.

[0042] A third aspect of the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps:

[0043] Sequentially obtain the timestamp when each feature point on the object to be measured is scanned by a pre-deployed single-line laser radar, the laser scanning data at the timestamp, and the radar posture data at the timestamp;

[0044] Mapping the laser scanning data of each feature point into a polar coordinate system in a timestamp order to obtain first peripheral shape point cloud data of the object to be measured in the polar coordinate system;

[0045] Establishing a rectangular coordinate system, converting the first peripheral shape point cloud data into second peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0046] The radar posture data at each time stamp is fused with the second peripheral shape point cloud data on a time stamp basis to obtain third peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0047] Generating a curve function for describing the peripheral shape characteristics of the object to be measured according to the third peripheral shape point cloud data;

[0048] The length corresponding to the curve function is calculated, and the length is used as the object circumference of the object to be measured.

[0049] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor performs the following steps:

[0050] Sequentially obtain the timestamp when each feature point on the object to be measured is scanned by a pre-deployed single-line laser radar, the laser scanning data at the timestamp, and the radar posture data at the timestamp;

[0051] Mapping the laser scanning data of each feature point into a polar coordinate system in a timestamp order to obtain first peripheral shape point cloud data of the object to be measured in the polar coordinate system;

[0052] Establishing a rectangular coordinate system, converting the first peripheral shape point cloud data into second peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0053] The radar posture data at each time stamp is fused with the second peripheral shape point cloud data on a time stamp basis to obtain third peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0054] Generating a curve function for describing the peripheral shape characteristics of the object to be measured according to the third peripheral shape point cloud data;

[0055] The length corresponding to the curve function is calculated, and the length is used as the object circumference of the object to be measured.

[0056] The present invention combines the laser scanning data of the single-line laser radar and the radar posture data to achieve an accurate description of the peripheral shape characteristics of the object and an accurate calculation of the object's circumference. The present invention has the advantages of non-contact, high precision, and high efficiency, and is suitable for precision measurement, medical measurement, and special environment measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0058] in:

[0059] Figure 1 is a flow chart of a method for measuring the circumference of an object in one embodiment;

[0060] Figure 2 is a structural block diagram of an object circumference measuring device in one embodiment;

[0061] Figure 3 FIG. 4 is a structural block diagram of a computer device in one embodiment. DETAILED DESCRIPTION

[0062] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] like Figure 1As shown, in one embodiment, a method for measuring the circumference of an object is provided. The method can be applied to a terminal or a server. This embodiment is illustrated by applying the method to a terminal. The method for measuring the circumference of an object specifically includes the following steps:

[0064] S1: sequentially obtaining the timestamp when each feature point on the object to be measured is scanned by a pre-deployed single-line laser radar, the laser scanning data at the timestamp, and the radar posture data at the timestamp;

[0065] S2: Mapping the laser scanning data of each feature point into a polar coordinate system in a timestamp order to obtain first peripheral shape point cloud data of the object to be measured in the polar coordinate system;

[0066] S3: establishing a rectangular coordinate system, and converting the first peripheral shape point cloud data into second peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0067] S4: fusing the radar posture data at each time stamp with the second peripheral shape point cloud data on a time stamp basis to obtain third peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0068] S5: generating a curve function for describing the peripheral shape characteristics of the object to be measured according to the third peripheral shape point cloud data;

[0069] S6: Calculate the length corresponding to the curve function, and use the length as the object circumference of the object to be measured.

[0070] In this embodiment, in the above step S1, the above laser scanning data is the data used to characterize the distance and angle corresponding to each feature point on the object to be measured by receiving the reflected signal after emitting a laser pulse during the scanning process of a single-line laser radar. The above radar posture data is the position and direction information of the laser radar during the scanning process, for example, including the translation (position change) and rotation (direction change) data of the radar. The scanned object includes multiple feature points for expressing the surface shape information of the scanned object.

[0071] The single-line laser radar is pre-deployed around the object to be measured or moved along its periphery to scan each feature point of the object in sequence. During the scanning process, the timestamp of each feature point being scanned, the corresponding laser scanning data, and the radar's posture data are recorded in real time.

[0072] In the above step S2, the polar coordinate system is a plane coordinate system with a certain point as the pole and a ray drawn from the point as the polar axis. In the polar coordinate system, the position of a point is determined by its distance to the pole (i.e., the polar diameter) and the angle with the polar axis (i.e., the polar angle). The laser scanning data of each feature point obtained in step S1 is mapped to the polar coordinate system in the order of timestamps.

[0073] In the above step S3, the rectangular coordinate system is composed of two perpendicular coordinate axes (x-axis and y-axis). A rectangular coordinate system is established, and the first peripheral shape point cloud data in the polar coordinate system is converted into the second peripheral shape point cloud data in the rectangular coordinate system using the following mathematical conversion formula. The mathematical conversion formula is:

[0074]

[0075] Among them, θ k is the angle in the laser scanning data corresponding to the kth timestamp; ρ k is the distance (i.e., polar diameter) in the laser scanning data corresponding to the kth timestamp; (x k ,y k ) is the rectangular coordinate of the laser scanning data corresponding to the kth timestamp in the rectangular coordinate system.

[0076] This step S3 converts the point cloud data from the polar coordinate system to a more commonly used rectangular coordinate system to facilitate subsequent data processing and analysis.

[0077] In the above step S4, the radar posture data at each time stamp is fused with the second peripheral shape point cloud data on a time stamp basis, so as to apply the radar posture information at each time point to the corresponding point cloud data to construct a complete three-dimensional shape of the object to be measured.

[0078] In the above step S5, the above curve function is used to describe the peripheral shape characteristics of the object to be measured. For example, it can be a parametric equation or other forms of mathematical expressions.

[0079] In the above step S6, in some feasible embodiments, a mathematical method (such as the arc length formula in calculus, numerical integration, etc.) can be used to calculate the length corresponding to the curve function, and the length is used as the object circumference of the object to be measured.

[0080] This embodiment combines the laser scanning data of the single-line laser radar and the radar posture data to achieve an accurate description of the peripheral shape characteristics of the object and an accurate calculation of the object's circumference. The method of this embodiment has the advantages of non-contact, high precision, and high efficiency, and is suitable for precision measurement, medical measurement, and special environment measurement.

[0081] In a specific embodiment, the step S1 of sequentially acquiring the timestamp when each feature point on the object to be measured is scanned by a pre-deployed single-line laser radar, the laser scanning data at the timestamp, and the radar pose data at the timestamp includes:

[0082] S101: emitting a scanning laser beam to the object to be measured through a pre-deployed single-line laser radar;

[0083] S102: upon receiving a reflected light signal after the scanning laser beam reaches the current feature point on the object to be measured, recording the current time as a timestamp, and recording the position and yaw angle of the single-line laser radar at the timestamp, and using the position and yaw angle as radar posture data;

[0084] S103: parsing the reflected light signal to obtain the angle and distance corresponding to the current feature point, and using the angle and distance as the laser scanning data, wherein the angle is the angle between the reflected light of the current feature point and a predefined reference direction of the single-line laser radar, and the distance is the distance between the current feature point and the single-line laser radar;

[0085] S104: Adjust the emission direction of the scanning laser beam of the single-line laser radar and the relative position of the object to be measured, and execute again the step of emitting the scanning laser beam to the object to be measured by the pre-deployed single-line laser radar.

[0086] In this embodiment, in the above step S101, a scanning laser beam is emitted to the object to be measured by a pre-deployed single-line laser radar, and the laser beam is reflected back when encountering the surface of the object to form a reflected light signal. The scanning method of the single-line laser radar is usually achieved by a rotating mirror or laser transmitter to ensure that the laser beam can cover the entire surface of the object to be measured or a predetermined scanning area.

[0087] In the above step S102, when the single-line laser radar receives the reflected light signal from the current feature point on the object to be measured, the current time is recorded as a timestamp, and the position and yaw angle of the single-line laser radar at this time are recorded. The above position refers to the coordinates of the laser radar in three-dimensional space, and the above yaw angle refers to the angle between the scanning direction of the laser radar and a predefined reference direction (such as the horizontal direction, the axis of the laser radar, or the initial emission direction).

[0088] In the above step S103, after receiving the reflected light signal, it is parsed to obtain the angle and distance information corresponding to the current feature point. The above angle refers to the angle between the reflected light and the predefined reference direction of the single-line laser radar. The above distance refers to the straight-line distance between the current feature point and the single-line laser radar, which can be calculated by measuring the flight time of the laser beam (i.e., the time difference from the emission to the reception of the laser beam) and applying the speed of light formula.

[0089] In the above step S104, after completing the scanning of the current feature point, the emission direction of the scanning laser beam of the single-line laser radar is adjusted to scan the next feature point. For example, this can be achieved by changing the rotation angle of the laser emitter or moving the position of the laser radar. After the adjustment is completed, step S101 is executed again, that is, the scanning laser beam is emitted to the object to be measured, and steps S102 to S103 are repeated until the scanning of the entire object to be measured is completed.

[0090] In a specific embodiment, the laser scanning data includes angles and distances, and the step S2 of mapping the laser scanning data of each feature point to a polar coordinate system in a timestamp order to obtain first peripheral shape point cloud data of the object to be measured in the polar coordinate system includes:

[0091] S201: Establish polar coordinate system;

[0092] S202: Take the angle corresponding to each timestamp as the polar angle, take the distance corresponding to each timestamp as the polar diameter, and take a group of polar angles and polar diameters corresponding to a timestamp as a group of ordered number pairs, and plot the ordered number pairs corresponding to each of the timestamps one by one in the polar coordinate system to obtain the first peripheral shape point cloud data of the object to be measured in the polar coordinate system.

[0093] In this embodiment, in the above step S201, the center point of the single-line laser radar can be selected as the origin, and the initial scanning direction of the single-line laser radar can be selected as the positive direction of the polar axis.

[0094] In the above step S202, all timestamps are traversed, and for each timestamp, the corresponding laser scanning data is extracted, that is, the angle θ in the laser scanning data corresponding to the kth timestamp is k (i.e., polar angle); the distance ρ in the laser scanning data corresponding to the kth timestamp k (i.e., polar diameter). Combine a set of polar angles and polar diameters corresponding to each timestamp into an ordered pair (θ k ,ρ k ), represented as a point in the polar coordinate system. In the established polar coordinate system, all points corresponding to the ordered number pairs are plotted one by one, and these point sets constitute the first peripheral shape point cloud data of the object to be measured in the polar coordinate system.

[0095] In a specific embodiment, the step S4 of fusing the radar pose data at each time stamp with the second peripheral shape point cloud data by time stamp to obtain the third peripheral shape point cloud data of the object to be measured in the rectangular coordinate system includes:

[0096] S401: taking the position and yaw angle in the radar posture data corresponding to the first timestamp as the initial position and initial yaw angle respectively;

[0097] S402: Calculate the position difference between the position in the radar pose data corresponding to each time stamp except the first time stamp and the initial position, and the yaw angle difference between the yaw angle in the radar pose data corresponding to each time stamp except the first time stamp and the initial yaw angle;

[0098] S403: Use the position difference and the yaw angle difference corresponding to each time stamp to fuse and correct the rectangular coordinates of the corresponding timestamps in the second peripheral shape point cloud data to obtain the fused coordinate data corresponding to each time stamp, and use the collection of each fused coordinate data corresponding to each time stamp as the third peripheral shape point cloud data.

[0099] In this embodiment, in the above step S401, the position and yaw angle information at the first timestamp are extracted from the radar posture data as the reference point (ie, the origin) and initial direction of the entire data fusion process.

[0100] In the above step S402, the movement and rotation of the radar relative to the initial state at each timestamp can be accurately described through the position difference and the yaw angle difference.

[0101] In the above step S403, for the second peripheral shape point cloud data at each timestamp, the position difference and the yaw angle difference at the corresponding timestamp are used to perform coordinate transformation. Specifically, the step S403 of using the position difference and the yaw angle difference corresponding to each timestamp to fuse and correct the rectangular coordinates of the corresponding timestamp in the second peripheral shape point cloud data to obtain the fused coordinate data corresponding to each timestamp is performed using the formula:

[0102] θ=yaw k -yaw0

[0103]

[0104] Among them, (X k ,Y k ) is the rectangular coordinate of the point corresponding to the kth timestamp in the rectangular coordinate system; is the position of the single-line laser radar corresponding to the kth timestamp, and the initial position is set to is (0, 0); θ is the yaw angle difference, yaw0 is the initial yaw angle, yaw k is the yaw angle of the single-line lidar corresponding to the k-th timestamp.

[0105] The transformed coordinates are the fused coordinate data at the timestamp. The fused coordinate data at all timestamps are merged to form the final third peripheral shape point cloud data.

[0106] Through the coordinate transformation and correction of each timestamp, the precise alignment and fusion of point cloud data at different timestamps are achieved, thereby constructing the complete point cloud data of the peripheral shape of the object to be measured in the rectangular coordinate system.

[0107] In a specific embodiment, the step S5 of generating a curve function for describing the peripheral shape characteristics of the object to be measured according to the third peripheral shape point cloud data comprises:

[0108] S501: Preprocessing the third peripheral shape point cloud data to obtain preprocessed point cloud data, wherein the preprocessing includes at least one of conditional filtering, noise removal, and resampling;

[0109] S502: Performing curve fitting on the pre-processed point cloud data using a cubic B-spline curve to obtain a curve function for describing the peripheral shape characteristics of the object to be measured.

[0110] In a specific embodiment, in the above step S501, the preprocessing step improves the quality and usability of the third peripheral shape point cloud data through operations such as conditional filtering, noise removal and / or resampling.

[0111] Conditional filtering: Filter the point cloud data according to the set conditions (such as the density of the point cloud data, the distance threshold, the normal direction, etc.), remove the points that do not meet the conditions, and retain the point cloud data that meets the requirements. This helps to reduce redundancy and abnormal points in the data.

[0112] Noise removal: Use radius filtering and other methods to remove noise points in point cloud data. By setting a radius threshold for the radius filter, if a point does not find other points within the radius threshold, it is considered as noise and filtered out, thereby improving the accuracy and smoothness of the data.

[0113] Resampling: Perform equidistant resampling on the point cloud data and set a search radius r s , with the i-th point (i∈N + ) as the center of the circle, select the point closest to the circumference as the i+1th point, take the i+1th point as the center of the circle, and then make a circle with a radius of r sThe point closest to the circumference of the circle is selected as the i+2th point (excluding the point that was once the center of the circle). Repeat this process until you return to the initial point.

[0114] In the above step S502, the cubic B-spline curve is a smooth continuous curve, which is composed of a series of cubic polynomial segments, and these segments smoothly transition between control points, and are suitable for describing complex shape features. Specifically, the cubic B-spline curve fitting algorithm is adopted, and the control point set is first obtained by using the LU decomposition method, and the basis function and the control point set in the cubic B-spline curve equation are substituted into the total equation of the B-spline curve to obtain the cubic B-spline curve equation.

[0115] In a specific embodiment, the step S6 of calculating the length corresponding to the curve function and taking the length as the object perimeter of the object to be measured includes:

[0116] S601: Divide the entire interval of the curve function into a plurality of sub-intervals;

[0117] S602: In each of the sub-intervals, the Simpson formula is used to perform integration to calculate the curve length of each sub-interval;

[0118] S603: Add the curve lengths of the sub-intervals to obtain a length corresponding to the curve function, and use the length as the object circumference of the object to be measured.

[0119] In this embodiment, in the above step S601, the entire interval is evenly or unevenly divided into several smaller sub-intervals according to the required accuracy and calculation efficiency. The length of each sub-interval can be adjusted according to actual conditions to ensure the accuracy and stability of the calculation results.

[0120] In the above step S602, the adaptive Simpson's formula is applied to perform numerical integration on each subinterval to calculate the arc length of the curve function on the subinterval. The Simpson's formula is a commonly used numerical integration method, which approximates the integral value of the function on the interval by taking a weighted average of the values ​​of the function at the endpoints and the midpoint of the interval.

[0121] In the above step S603, by adding the curve lengths of each sub-interval, the total length corresponding to the entire curve function can be obtained, thereby accurately calculating the object perimeter of the object to be measured. This method is suitable for processing various complex curve shapes.

[0122] like Figure 2 As shown, in one embodiment, a device for measuring the circumference of an object is provided, the device comprising:

[0123] A data acquisition module 10 is used to sequentially acquire the timestamp when each feature point on the object to be measured is scanned by a pre-deployed single-line laser radar, the laser scanning data at the timestamp, and the radar posture data at the timestamp;

[0124] A first point cloud data generating module 20 is used to map the laser scanning data of each feature point to a polar coordinate system according to a timestamp order, so as to obtain first peripheral shape point cloud data of the object to be measured in the polar coordinate system;

[0125] The second point cloud data generating module 30 is used to establish a rectangular coordinate system and convert the first peripheral shape point cloud data into the second peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0126] A third point cloud data generating module 40 is used to perform data fusion on a time stamp basis on the radar posture data at each time stamp and the second peripheral shape point cloud data to obtain third peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0127] A curve function generating module 50, used for generating a curve function for describing the peripheral shape characteristics of the object to be measured according to the third peripheral shape point cloud data;

[0128] The object perimeter calculation module 60 is used to calculate the length corresponding to the curve function and use the length as the object perimeter of the object to be measured.

[0129] In a specific embodiment, the data acquisition module 10 includes:

[0130] A laser emitting unit, used for emitting a scanning laser beam to the object to be measured through a pre-deployed single-line laser radar;

[0131] A recording unit, configured to record the current time as a timestamp when receiving a reflected light signal after the scanning laser beam reaches the current feature point on the object to be measured, and to record the position and yaw angle of the single-line laser radar at the timestamp, and use the position and yaw angle as radar posture data;

[0132] A parsing unit, used to parse the reflected light signal, obtain the angle and distance corresponding to the current feature point, and use the angle and distance as the laser scanning data, wherein the angle is the angle between the reflected light of the current feature point and a predefined reference direction of the single-line laser radar, and the distance is the distance between the current feature point and the single-line laser radar;

[0133] The position adjustment unit is used to adjust the emission direction of the scanning laser beam of the single-line laser radar and the relative position of the object to be measured, and to perform again the step of emitting the scanning laser beam to the object to be measured by the pre-deployed single-line laser radar.

[0134] In a specific embodiment, the first point cloud data generating module 20 includes:

[0135] A polar coordinate system establishing unit, used for establishing a polar coordinate system;

[0136] The first point cloud data drawing unit is used to take the angle corresponding to each timestamp as the polar angle, the distance corresponding to each timestamp as the polar diameter, and a group of polar angles and polar diameters corresponding to a timestamp as a group of ordered number pairs, and draw the ordered number pairs corresponding to each of the timestamps one by one in the polar coordinate system to obtain the first peripheral shape point cloud data of the object to be measured in the polar coordinate system.

[0137] In a specific embodiment, the third point cloud data generating module 40 includes:

[0138] An initial value setting unit, used to use the position and yaw angle in the radar posture data corresponding to the first timestamp as the initial position and initial yaw angle respectively;

[0139] A difference calculation unit, used for calculating the position difference between the position in the radar posture data corresponding to each time stamp except the first time stamp and the initial position, and the yaw angle difference between the yaw angle in the radar posture data corresponding to each time stamp except the first time stamp and the initial yaw angle;

[0140] The third point cloud data generating unit is used to use the position difference and the yaw angle difference corresponding to each time stamp to fuse and correct the rectangular coordinates of the corresponding timestamps in the second peripheral shape point cloud data, so as to obtain the fused coordinate data corresponding to each time stamp, and take the collection of each fused coordinate data corresponding to each time stamp as the third peripheral shape point cloud data.

[0141] In a specific embodiment, the third point cloud data generating unit adopts the formula:

[0142] θ=yaw k -yaw0

[0143]

[0144] Among them, (X k ,Y k ) is the rectangular coordinate of the point corresponding to the kth timestamp in the rectangular coordinate system; is the position of the single-line laser radar corresponding to the kth timestamp, and the initial position is set to is (0, 0); θ is the yaw angle difference, yaw0 is the initial yaw angle, yaw k is the yaw angle of the single-line lidar corresponding to the k-th timestamp.

[0145] In a specific embodiment, the curve function generating module 50 includes:

[0146] A data preprocessing unit, configured to preprocess the third peripheral shape point cloud data to obtain preprocessed point cloud data, wherein the preprocessing includes at least one of conditional filtering, noise removal, and resampling;

[0147] The curve fitting unit is used to perform curve fitting on the pre-processed point cloud data using a cubic B-spline curve to obtain a curve function for describing the peripheral shape characteristics of the object to be measured.

[0148] In a specific embodiment, the object perimeter calculation module 60 includes:

[0149] A sub-interval division unit, used for dividing the entire interval of the curve function into a plurality of sub-intervals;

[0150] A sub-interval length calculation unit, used for calculating the curve length of each sub-interval by integrating the Simpson formula on each of the sub-intervals;

[0151] The object perimeter calculation unit is used to add the curve lengths of each of the sub-intervals to obtain the length corresponding to the curve function, and use the length as the object perimeter of the object to be measured.

[0152] This embodiment combines the laser scanning data of the single-line laser radar and the radar posture data to achieve an accurate description of the peripheral shape characteristics of the object and an accurate calculation of the object's circumference. This embodiment has the advantages of non-contact, high precision, and high efficiency, and is suitable for precision measurement, medical measurement, and special environment measurement.

[0153] Figure 3 FIG. 1 shows an internal structure diagram of a computer device in an embodiment. The computer device may be a terminal or a server. Figure 3As shown, the computer device includes a processor, a memory and a network interface connected via a system bus. The memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor may implement the object circumference measurement method. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor may implement the object circumference measurement method. Those skilled in the art will understand that Figure 3 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present invention, and does not constitute a limitation on the computer device to which the solution of the present invention is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0154] In one embodiment, a computer device is provided, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps:

[0155] Sequentially obtain the timestamp when each feature point on the object to be measured is scanned by a pre-deployed single-line laser radar, the laser scanning data at the timestamp, and the radar posture data at the timestamp;

[0156] Mapping the laser scanning data of each feature point into a polar coordinate system in a timestamp order to obtain first peripheral shape point cloud data of the object to be measured in the polar coordinate system;

[0157] Establishing a rectangular coordinate system, converting the first peripheral shape point cloud data into second peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0158] The radar posture data at each time stamp is fused with the second peripheral shape point cloud data on a time stamp basis to obtain third peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0159] Generating a curve function for describing the peripheral shape characteristics of the object to be measured according to the third peripheral shape point cloud data;

[0160] The length corresponding to the curve function is calculated, and the length is used as the object circumference of the object to be measured.

[0161] This embodiment combines the laser scanning data of the single-line laser radar and the radar posture data to achieve an accurate description of the peripheral shape characteristics of the object and an accurate calculation of the object's circumference. This embodiment has the advantages of non-contact, high precision, and high efficiency, and is suitable for precision measurement, medical measurement, and special environment measurement.

[0162] In one embodiment, a computer-readable storage medium is provided, storing a computer program, wherein when the computer program is executed by a processor, the processor performs the following steps:

[0163] Sequentially obtain the timestamp when each feature point on the object to be measured is scanned by a pre-deployed single-line laser radar, the laser scanning data at the timestamp, and the radar posture data at the timestamp;

[0164] Mapping the laser scanning data of each feature point into a polar coordinate system in a timestamp order to obtain first peripheral shape point cloud data of the object to be measured in the polar coordinate system;

[0165] Establishing a rectangular coordinate system, converting the first peripheral shape point cloud data into second peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0166] The radar posture data at each time stamp is fused with the second peripheral shape point cloud data on a time stamp basis to obtain third peripheral shape point cloud data of the object to be measured in the rectangular coordinate system;

[0167] Generating a curve function for describing the peripheral shape characteristics of the object to be measured according to the third peripheral shape point cloud data;

[0168] The length corresponding to the curve function is calculated, and the length is used as the object circumference of the object to be measured.

[0169] This embodiment combines the laser scanning data of the single-line laser radar and the radar posture data to achieve an accurate description of the peripheral shape characteristics of the object and an accurate calculation of the object's circumference. This embodiment has the advantages of non-contact, high precision, and high efficiency, and is suitable for precision measurement, medical measurement, and special environment measurement.

[0170] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided by the present invention can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0171] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0172] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for measuring the circumference of an object, characterized in that: The method comprises: Sequentially obtain the timestamp when each feature point on the object to be measured is scanned by a pre-deployed single-line laser radar, the laser scanning data at the timestamp, and the radar posture data at the timestamp; Mapping the laser scanning data of each feature point into a polar coordinate system in a timestamp order to obtain first peripheral shape point cloud data of the object to be measured in the polar coordinate system; Establishing a rectangular coordinate system, converting the first peripheral shape point cloud data into second peripheral shape point cloud data of the object to be measured in the rectangular coordinate system; The radar posture data at each time stamp is fused with the second peripheral shape point cloud data on a time stamp basis to obtain third peripheral shape point cloud data of the object to be measured in the rectangular coordinate system; Generating a curve function for describing the peripheral shape characteristics of the object to be measured according to the third peripheral shape point cloud data; The length corresponding to the curve function is calculated, and the length is used as the object circumference of the object to be measured.

2. The object circumference measurement method according to claim 1, characterized in that: The step of sequentially acquiring the timestamp when each feature point on the object to be measured is scanned by a pre-deployed single-line laser radar, the laser scanning data at the timestamp, and the radar pose data at the timestamp, comprises: A scanning laser beam is emitted to the object to be measured through a pre-deployed single-line laser radar; When receiving the reflected light signal after the scanning laser beam reaches the current feature point on the object to be measured, the current time is recorded as a timestamp, and the position and yaw angle of the single-line laser radar under the timestamp are recorded, and the position and yaw angle are used as radar posture data; Analyze the reflected light signal to obtain the angle and distance corresponding to the current feature point, and use the angle and distance as the laser scanning data, wherein the angle is the angle between the reflected light of the current feature point and the predefined reference direction of the single-line laser radar, and the distance is the distance between the current feature point and the single-line laser radar; Adjust the emission direction of the scanning laser beam of the single-line laser radar and the relative position of the object to be measured, and perform the step of emitting the scanning laser beam to the object to be measured by the pre-deployed single-line laser radar again.

3. The object circumference measurement method according to claim 2, characterized in that: The laser scanning data includes angles and distances. The step of mapping the laser scanning data of each feature point to a polar coordinate system in a timestamp order to obtain first peripheral shape point cloud data of the object to be measured in the polar coordinate system includes: Establish polar coordinate system; The angle corresponding to each timestamp is taken as the polar angle, the distance corresponding to each timestamp is taken as the polar diameter, and a group of polar angles and polar diameters corresponding to a timestamp is taken as a group of ordered number pairs. The ordered number pairs corresponding to each of the timestamps are plotted one by one in the polar coordinate system to obtain the first peripheral shape point cloud data of the object to be measured in the polar coordinate system.

4. The object circumference measurement method according to claim 2, characterized in that: The step of fusing the radar posture data at each time stamp with the second peripheral shape point cloud data by time stamp to obtain the third peripheral shape point cloud data of the object to be measured in the rectangular coordinate system includes: The position and yaw angle in the radar posture data corresponding to the first timestamp are used as the initial position and initial yaw angle respectively; Calculate the position difference between the position in the radar pose data corresponding to each time stamp except the first time stamp and the initial position, and the yaw angle difference between the yaw angle in the radar pose data corresponding to each time stamp except the first time stamp and the initial yaw angle; The position difference and the yaw angle difference corresponding to each timestamp are used to fuse and correct the rectangular coordinates of the corresponding timestamps in the second peripheral shape point cloud data to obtain the fused coordinate data corresponding to each timestamp, and the collection of each fused coordinate data corresponding to each timestamp is used as the third peripheral shape point cloud data.

5. The object circumference measurement method according to claim 4, characterized in that: The step of using the position difference and the yaw angle difference corresponding to each time stamp to fuse and correct the rectangular coordinates of the corresponding time stamp in the second peripheral shape point cloud data to obtain the fused coordinate data corresponding to each time stamp adopts the formula: θ=yaw k -yaw0 Among them, (X k ,Y k ) is the rectangular coordinate of the point corresponding to the kth timestamp in the rectangular coordinate system; is the position of the single-line laser radar corresponding to the kth timestamp, and the initial position is set to is (0, 0); θ is the yaw angle difference, yaw0 is the initial yaw angle, yaw k is the yaw angle of the single-line lidar corresponding to the k-th timestamp.

6. The object circumference measurement method according to claim 1, characterized in that: The step of generating a curve function for describing the peripheral shape features of the object to be measured according to the third peripheral shape point cloud data comprises: Preprocessing the third peripheral shape point cloud data to obtain preprocessed point cloud data, wherein the preprocessing includes at least one of conditional filtering, noise removal, and resampling; The pre-processed point cloud data is subjected to curve fitting using a cubic B-spline curve to obtain a curve function for describing the peripheral shape characteristics of the object to be measured.

7. The object circumference measurement method according to claim 1, characterized in that: The step of calculating the length corresponding to the curve function and taking the length as the circumference of the object to be measured comprises: Dividing the entire interval of the curve function into a plurality of subintervals; In each of the subintervals, the Simpson formula is used to perform integration and calculate the curve length of each subinterval; The curve lengths of the sub-intervals are added together to obtain a length corresponding to the curve function, and the length is used as the object circumference of the object to be measured.

8. An object circumference measuring device, characterized in that: The device comprises: A data acquisition module is used to sequentially acquire the timestamp when each feature point on the object to be measured is scanned by a pre-deployed single-line laser radar, the laser scanning data at the timestamp, and the radar posture data at the timestamp; A first point cloud data generating module, used for mapping the laser scanning data of each feature point into a polar coordinate system according to a timestamp sequence, to obtain first peripheral shape point cloud data of the object to be measured in the polar coordinate system; A second point cloud data generating module is used to establish a rectangular coordinate system and convert the first peripheral shape point cloud data into second peripheral shape point cloud data of the object to be measured in the rectangular coordinate system; A third point cloud data generating module is used to perform data fusion on a timestamp-by-timestamp basis on the radar posture data at each timestamp and the second peripheral shape point cloud data to obtain third peripheral shape point cloud data of the object to be measured in the rectangular coordinate system; A curve function generating module, used for generating a curve function for describing the peripheral shape characteristics of the object to be measured according to the third peripheral shape point cloud data; The object perimeter calculation module is used to calculate the length corresponding to the curve function and use the length as the object perimeter of the object to be measured.

9. A computer-readable storage medium, characterized in that: A computer program is stored, and when the computer program is executed by a processor, the processor executes the steps of the object circumference measurement method according to any one of claims 1 to 7.

10. A computer device, characterized in that: The device comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the object circumference measurement method according to any one of claims 1 to 7.

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