Method and device for foreign object screening of a belt conveyor based on laser scanning

Abstract

The application discloses a belt conveyor foreign matter screening method and device based on laser scanning. The method comprises the following steps: determining the contour of the conveying belt of the belt conveyor according to a first point cloud data set, wherein the first point cloud data set comprises a set of point cloud data in an empty state of the conveying belt; matching a second point cloud data set with a third point cloud data set corresponding to the contour according to the scanning angle, to obtain a matching result; determining a target point cloud data set in the second point cloud data set which does not match the third point cloud data set under the same scanning angle according to the matching result; determining the position information of the coal flow conveyed by the conveying belt in the third point cloud data set; and screening non-coal flow objects within a predetermined range of the belt conveyor from the target point cloud data set according to the position information of the coal flow. The application solves the technical problem that it is difficult to monitor the on-site situation of the belt conveyor and detect foreign matters due to monitoring difficulties in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of foreign matter detection, in particular to a belt conveyor foreign matter screening method and device based on laser scanning. BACKGROUND

[0002] In traditional engineering, the monitoring and fault detection of belt conveyors generally adopts two ways of manual inspection and video monitoring. Manual inspection means that workers need to go to the scene to judge whether the belt conveyor has failed through observation, sound listening and instrument measurement. Video monitoring means that a large number of cameras are erected at the belt conveyor transportation site, and a large amount of video information is collected to a data central platform for remote processing by monitoring personnel.

[0003] However, the following shortcomings usually exist when judging whether the belt conveyor has failed through the two ways: 1) manual inspection wastes manpower, and the transportation site generally has safety hazards, which may cause personnel casualties; 2) the total journey of belt transportation is long, workers can only check at several key points, and when the site is monitored through video, only some obvious faults can be analyzed and judged, and faults are easy to be missed; 3) quantitative indicators such as coal flow cannot be obtained, a high-precision three-dimensional model cannot be formed to reproduce the scene, the belt conveyor cannot be detected visually, and it is difficult to monitor the change of coal flow in real time, mark abnormal targets in the scene, etc.

[0004] At present, no effective solution has been proposed for the problem that it is difficult to monitor the scene of the belt conveyor and thus difficult to detect foreign matter due to monitoring difficulties in the prior art. SUMMARY

[0005] The embodiment of the present application provides a belt conveyor foreign matter screening method and device based on laser scanning, so as to at least solve the technical problem that it is difficult to monitor the scene of the belt conveyor and thus difficult to detect foreign matter due to monitoring difficulties in the prior art.

[0006] According to one aspect of the embodiment of the present application, a belt conveyor foreign matter screening method based on laser scanning is provided, which comprises: determining the contour of the conveyor belt of the belt conveyor according to a first point cloud data set, wherein the first point cloud data set comprises a set of point cloud data in the empty state of the conveyor belt; matching a second point cloud data set with a third point cloud data set corresponding to the contour according to the scanning angle to obtain a matching result; determining a target point cloud data set in the second point cloud data set which does not match the third point cloud data set under the same scanning angle according to the matching result; determining the position information of the coal flow conveyed by the conveyor belt in the third point cloud data set; and screening non-coal flow objects within the predetermined range of the belt conveyor from the target point cloud data set according to the position information of the coal flow.

[0007] Optionally, the profile of the conveyor belt of the belt conveyor is determined according to the first point cloud data set, comprising: triggering the laser radar to perform a predetermined number of scanning operations on the conveyor belt when the conveyor belt is in an empty state to obtain the first point cloud data set; determining a scanning angle of the laser radar collecting each point cloud data in the first point cloud data set according to the first point cloud data set; determining an initial point cloud distance corresponding to the scanning angle of each point cloud data to obtain an initial point cloud data set, wherein the point cloud distance represents the vertical distance between the laser radar and the conveyor belt at the scanning angle; and determining the profile according to the initial point cloud data set.

[0008] Optionally, the initial point cloud distance satisfies a Gaussian mixture distribution, wherein the Gaussian mixture distribution is represented by a first formula: bθ represents the initial point cloud distance, θ represents the scanning angle, k represents the number of Gaussian distributions, ω i represents the weight of the i-th Gaussian distribution, μ i represents the mean of the i-th Gaussian distribution of b θ represents the variance of the i-th matching Gaussian distribution of b θ

[0009] Optionally, the target point cloud data set in the second point cloud data set that does not match the third point cloud data set at the same scanning angle is determined according to the matching result, comprising: matching each second point cloud data in the second point cloud data set with the Gaussian mixture distribution of each third point cloud data in the third point cloud data set respectively, and matching a plurality of fourth point cloud data in the first point cloud data set to the second point cloud data set by a second formula, wherein the matching degree of the second point cloud data set is greater than a predetermined matching degree threshold, to obtain the fourth point cloud data set, wherein the second formula is: n represents the optimal matching of c θ is the n-th Gaussian distribution of b θ , c θ represents the second point cloud data; determining the point cloud data in the fourth point cloud data set that satisfies a predetermined relationship as background point cloud data in the second point cloud data set, wherein the predetermined relationship is: ω i ≥ T, c θ - μ i ≤ 3σ n , T represents a weight threshold; and determining the part of the second point cloud data set excluding the background point cloud data as the target point cloud data set.

[0010] ​​Optionally, determining the position information of the coal flow conveyed by the conveyor belt in the third point cloud data set comprises: determining a maximum width of the conveyor belt; determining a minimum height difference of the conveyor belt in an empty state and the lidar; determining a first angle at which the lidar starts scanning the coal flow on the conveyor belt according to the maximum width and the minimum height difference by using a fourth formula, and simultaneously determining a second angle at which the lidar stops scanning the coal flow on the conveyor belt according to the maximum width and the minimum height difference by using a fifth formula, wherein the fourth formula is: θ s represents the first angle, θ max represents a maximum scanning range of the lidar, w represents the maximum width, and H represents the minimum height difference; and the fifth formula is: θ e represents the second angle; and the position information is determined according to the first angle and the second angle.

[0011] Optionally, the foreign matter screening method based on laser scanning of the belt conveyor further comprises: determining a rotating speed of the belt conveyor by an encoder in the belt conveyor; determining a transmission ratio of a speed reducer of the belt conveyor; determining a drum radius and a transmission efficiency of the belt conveyor; and determining a running speed of the conveyor belt according to the rotating speed, the transmission ratio, the drum radius, and the transmission efficiency by using a sixth formula, wherein the sixth formula is: v represents the running speed, λ represents the rotating speed, r represents the drum radius, β represents the transmission efficiency, and i represents the transmission ratio; and an instantaneous flow rate of the coal flow is determined by using a seventh formula, wherein the seventh formula is: V represents the instantaneous flow rate, δ represents an angle resolution of the lidar, s represents a first point at which a coal flow region starts to appear, and e represents a last point at which the coal flow region appears.

[0012] Optionally, after the contour of the conveyor belt of the belt conveyor is determined according to the first point cloud data set, the method further comprises: detecting the conveyor belt according to the contour to determine whether a crack appears in the conveyor belt; and generating first alarm information when it is determined that the crack appears in the conveyor belt, wherein the first alarm information is used to prompt that the crack appears in the conveyor belt.

[0013] Optionally, after the non-coal flow object within the predetermined range of the belt conveyor is screened from the target point cloud data set according to the position information of the coal flow, the method further comprises: generating second alarm information, wherein the second alarm information is used to prompt that the non-coal flow object exists within the predetermined range of the belt conveyor.

[0014] According to an aspect of the embodiments of the present application, there is also provided a foreign matter screening device for a belt conveyor based on laser scanning, comprising: a first determining unit configured to determine a profile of a conveyor belt of the belt conveyor according to a first point cloud data set, wherein the first point cloud data set comprises a set of point cloud data in an empty state of the conveyor belt; a matching unit configured to match a second point cloud data set with a third point cloud data set corresponding to the profile according to a scanning angle, to obtain a matching result; a second determining unit configured to determine a target point cloud data set in the second point cloud data set that does not match the third point cloud data set in the same scanning angle according to the matching result; a third determining unit configured to determine position information of a coal flow conveyed by the conveyor belt in the third point cloud data set; and a screening unit configured to screen a non-coal flow object within a predetermined range of the belt conveyor from the target point cloud data set according to the position information of the coal flow.

[0015] Optionally, the first determining unit comprises: an obtaining module configured to trigger the laser radar to perform a predetermined number of scanning operations on the conveyor belt when the conveyor belt is in an empty state, to obtain the first point cloud data set; a first determining module configured to determine a scanning angle of the laser radar collecting each point cloud data in the first point cloud data set according to the first point cloud data set; a second determining module configured to determine an initial point cloud distance corresponding to the scanning angle of each point cloud data, to obtain an initial point cloud data set, wherein the point cloud distance represents a vertical distance between the laser radar and the conveyor belt at the scanning angle; and a third determining module configured to determine the profile according to the initial point cloud data set.

[0016] Optionally, the initial point cloud distance satisfies a Gaussian mixture distribution, wherein the Gaussian mixture distribution is represented by a first formula: b θ wherein b represents the initial point cloud distance, θ represents the scanning angle, k represents a number of Gaussian distributions, ω i represents a weight of the i-th Gaussian distribution, μ i represents a mean value of the i-th Gaussian distribution, θ represents a variance of the i-th Gaussian distribution, θ

[0017] ​​Optionally, the second determining unit comprises a matching module configured to match each of the second point cloud data set with a Gaussian mixture distribution of each of the third point cloud data set, and match, in the first point cloud data set, a plurality of fourth point cloud data with which the matching degree of the second point cloud data set is greater than a predetermined matching degree threshold, to obtain the fourth point cloud data set, by a second formula, wherein the second formula is: n represents c θ The optimal matching is b θ The nth Gaussian distribution, c θ The second point cloud data; a fourth determining module configured to determine point cloud data in the fourth point cloud data set that satisfies a predetermined relationship as background point cloud data in the second point cloud data set, wherein the predetermined relationship is: i ω θ -μ i ≤3σ n , T represents a weight threshold; and a fifth determining module configured to determine, as the target point cloud data set, a part of the second point cloud data set other than the background point cloud data.

[0018] Optionally, the third determining unit comprises a sixth determining module configured to determine a maximum width of the conveyor belt; a seventh determining module configured to determine a minimum height difference of the conveyor belt in an empty state and the laser radar; and an eighth determining module configured to determine, according to the maximum width and the minimum height difference, a first angle at which the laser radar starts scanning coal flow on the conveyor belt by a fourth formula, and determine a second angle at which the laser radar last scans the coal flow on the conveyor belt by a fifth formula, wherein the fourth formula is: θ s represents the first angle, θ max represents a maximum scanning range of the laser radar, w represents the maximum width, and H represents the minimum height difference; and the fifth formula is: θ e represents the second angle; and a ninth determining module configured to determine the position information according to the first angle and the second angle.

[0019] Optionally, the belt conveyor foreign matter screening device based on laser scanning further comprises: a tenth determination module configured to determine the rotating speed of the belt conveyor through an encoder in the belt conveyor; an eleventh determination module configured to determine the transmission ratio of a speed reducer of the belt conveyor; a twelfth determination module configured to determine the drum radius and the transmission efficiency of the belt conveyor; a thirteenth determination module configured to determine the running speed of the conveyor belt according to the rotating speed, the transmission ratio, the drum radius, and the transmission efficiency through a sixth formula, wherein the sixth formula is: v represents the running speed, λ represents the rotating speed, r represents the drum radius, β represents the transmission efficiency, and i represents the transmission ratio; and a fourteenth determination module configured to determine the instantaneous flow of the coal flow through a seventh formula, wherein the seventh formula is: v represents the instantaneous flow, and δ represents the angular resolution of the laser radar.

[0020] Optionally, the belt conveyor foreign matter screening device based on laser scanning further comprises: a fourth determination unit configured to detect the conveyor belt according to the profile of the conveyor belt after determining the profile of the conveyor belt according to the first point cloud data set, to determine whether the conveyor belt has a crack; and a first generation unit configured to generate first alarm information when it is determined that the conveyor belt has a crack, wherein the first alarm information is used to prompt that the conveyor belt has a crack.

[0021] Optionally, the belt conveyor foreign matter screening device based on laser scanning further comprises: a second generation unit configured to generate second alarm information after screening out non-coal flow objects within the predetermined range of the belt conveyor from the target point cloud data set according to the position information of the coal flow, wherein the second alarm information is used to prompt that the non-coal flow objects exist within the predetermined range of the belt conveyor.

[0022] According to another aspect of the embodiments of the present application, a computer readable storage medium is also provided, which comprises a stored program, wherein the program performs any of the belt conveyor foreign matter screening methods based on laser scanning.

[0023] According to another aspect of the embodiments of the present application, a processor is also provided, which is used to run a program, wherein the program performs any of the belt conveyor foreign matter screening methods based on laser scanning when running.

[0024] In the embodiment of the present application, the profile of the conveyor belt of the belt conveyor is determined according to the first point cloud data set, wherein the first point cloud data set comprises a set of point cloud data in an empty state of the conveyor belt; the second point cloud data set is matched with the third point cloud data set corresponding to the profile according to the scanning angle, to obtain a matching result; the target point cloud data set in the second point cloud data set which does not match the third point cloud data set under the same scanning angle is determined according to the matching result; the position information of the coal flow conveyed by the conveyor belt in the third point cloud data set is determined; and the non-coal flow object within the predetermined range of the belt conveyor is screened from the target point cloud data set according to the position information of the coal flow. Through the technical scheme provided by the present application, the profile of the conveyor belt can be generated by using the point cloud data set in the empty state of the conveyor belt, then the point cloud data set collected in the coal flow conveying state is compared with the point cloud data corresponding to the profile of the conveyor belt according to the scanning angle, the target point cloud data set including the coal flow and foreign matter is obtained, and the foreign matter other than the coal flow is screened from the target point cloud data set according to the region where the coal flow appears, that is, the on-site situation of the belt conveyor can be monitored visually, the non-coal flow object on the belt conveyor is screened, the automatic screening of the foreign matter on the belt conveyor is realized, the labor cost is reduced, the safety hidden danger is reduced, and thus the technical problem that it is difficult to monitor the on-site situation of the belt conveyor and detect the foreign matter due to the monitoring difficulty in the prior art is solved. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings, which are included to provide a further understanding of the present application and are incorporated in and constitute a part of this application, illustrate embodiments of the present application and serve to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0026] Figure 1 is a hardware structure block diagram of a mobile terminal of a belt conveyor foreign matter screening method based on laser scanning according to an embodiment of the present application;

[0027] Figure 2 is a flow chart of a belt conveyor foreign matter screening method based on laser scanning according to an embodiment of the present application;

[0028] Figure 3 is a schematic diagram of point cloud data according to an embodiment of the present application;

[0029] Figure 4 is a schematic diagram of a coal flow position according to an embodiment of the present application;

[0030] Figure 5 is a schematic diagram of a belt conveyor foreign matter screening device based on laser scanning according to an embodiment of the present application. DETAILED DESCRIPTION

[0031] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0032] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0033] As described in the background section, existing technologies suffer from difficulties in monitoring the on-site conditions of belt conveyors, making it challenging to detect foreign objects. To address these shortcomings, embodiments of the present invention provide a method and apparatus for screening foreign objects in belt conveyors based on laser scanning.

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0035] The methods and embodiments provided in this invention can be executed on a mobile terminal, a computer terminal, or a similar computing device. Taking running on a mobile terminal as an example, Figure 1 This is a hardware structure block diagram of a mobile terminal for a foreign object screening method for belt conveyors based on laser scanning, according to an embodiment of the present invention. Figure 1 As shown, a mobile terminal may include one or more ( Figure 1 Only one is shown in the diagram. A processor 102 (which may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data are also shown. The mobile terminal may further include a transmission device 106 for communication functions and an input / output device 108. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the mobile terminal described above. For example, the mobile terminal may also include components that are more... Figure 1more or fewer components than shown or described, or with components arranged in different configurations and / or orders. Figure 1

[0036] The memory 104 is operable to store computer programs, such as software programs of application software and modules, such as a computer program corresponding to the foreign matter screening method for a belt conveyor based on laser scanning in embodiments of the present application. The processor 102 is operable to perform various functional applications and data processing, i.e., implement the above-described method, by running the computer program stored in the memory 104. The memory 104 can include a high-speed random access memory, and can further include a non-volatile memory, such as one or more magnetic storage devices, a flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 can further include a memory remotely disposed relative to the processor 102, which can be connected to the mobile terminal through a network. Examples of the above-described network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The transmission device 106 is operable to receive or send data via a network. The above-described network can specifically include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 106 includes a network interface controller (NIC), which can be connected to other network devices through a base station so as to be able to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (RF) module, which is operable to communicate with the Internet in a wireless manner.

[0037] According to embodiments of the present application, a method embodiment of a foreign matter screening method for a belt conveyor based on laser scanning is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system, such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown herein.

[0038] Figure 2 is a flowchart of a foreign matter screening method for a belt conveyor based on laser scanning according to embodiments of the present application, as shown in Figure 2 The method includes the following steps:

[0039] In step S202, a contour of a conveyor belt of the belt conveyor is determined according to a first point cloud data set, wherein the first point cloud data set includes a set of point cloud data in an empty state of the conveyor belt.

[0040] Optionally, the first point cloud data set includes point cloud data of the contour of the conveyor belt of the belt conveyor and point cloud data of other scannable backgrounds in the empty state of the conveyor belt.

[0041] ​According to the above embodiment of the present application, in the step S202, the profile of the conveyor belt of the belt conveyor is determined according to the first point cloud data set, which can include: triggering the laser radar to perform a predetermined number of scanning operations on the conveyor belt when the conveyor belt is in an empty state to obtain the first point cloud data set; determining the scanning angle of the laser radar collecting each point cloud data in the first point cloud data set according to the first point cloud data set; determining the initial point cloud distance corresponding to the scanning angle of each point cloud data to obtain the initial point cloud data set, wherein the point cloud distance represents the vertical distance between the laser radar and the conveyor belt at the scanning angle; and determining the profile according to the initial point cloud data set.

[0042] Optionally, the predetermined number of times refers to the number of times of scanning the conveyor belt by the laser radar. In this embodiment, the predetermined number of times can be multiple times, so as to sufficiently scan the conveyor belt, so that the obtained profile of the conveyor belt is relatively accurate.

[0043] In this embodiment, the conveyor belt in the empty state can be scanned multiple times until the point cloud data collected can determine the profile of the conveyor belt of the belt conveyor.

[0044] Optionally, the initial point cloud distance satisfies a Gaussian mixture distribution, wherein the Gaussian mixture distribution is represented by a first formula: b θ , wherein b represents the initial point cloud distance, θ represents the scanning angle, k represents the number of Gaussian distributions, ω i represents the weight of the i-th Gaussian distribution, μ i represents the mean value of the i-th matching Gaussian distribution of b θ , and σ θ represents the variance of the i-th matching Gaussian distribution of b θ .

[0045] In addition, the first point cloud data set collected is spliced, and a high-precision three-dimensional model of the belt conveyor can be formed after triangulation, which can be visually presented, so as to better monitor the belt conveyor.

[0046] For example, before the belt conveyor starts to convey the coal flow, the laser radar is used to scan the empty state of the belt conveyor multiple times, and each scanning angle θ of the laser radar has a unique point cloud distance b θ . Assuming that the distance obeys a Gaussian mixture distribution, that is, satisfies (first formula), wherein, k is generally 3-8, and the Gaussian mixture parameters (i.e. mean value and variance) of each point cloud distance b θ are statistically calculated and iterated, and then the initial point cloud distance b θThe set can form a contour of the conveyor belt of the belt conveyor.

[0047] In step S204, the second point cloud data set is matched with a third point cloud data set corresponding to the contour according to a scanning angle, to obtain a matching result.

[0048] Optionally, the second point cloud data set refers to a plurality of point cloud data sets obtained by the laser radar performing multiple scans on the scene after the belt conveyor starts conveying the coal flow.

[0049] Optionally, the third point cloud data set refers to a point cloud data set of the contour of the conveyor belt of the belt conveyor determined according to the first point cloud data set in step S202.

[0050] Optionally, the matching process is to filter out point cloud data in the second point cloud data set that does not belong to the contour of the conveyor belt (i.e., the third point cloud data set).

[0051] In step S206, the target point cloud data set that does not match the third point cloud data set in the second point cloud data set under the same scanning angle is determined according to the matching result.

[0052] Optionally, the same scanning angle refers to matching point cloud data under the same scanning angle of the laser radar in the second point cloud data set and the third point cloud data set in the matching process. If point cloud data under different scanning angles is matched, it is easy to make a false judgment. In this way, the target point cloud data set that does not match the point cloud data set corresponding to the contour of the conveyor belt can be accurately determined from the second point cloud data set scanned in real time.

[0053] In step S206, the target point cloud data set that does not match the third point cloud data set in the second point cloud data set under the same scanning angle is determined according to the matching result, including: matching each second point cloud data in the second point cloud data set with the Gaussian mixture distribution of each third point cloud data in the third point cloud data set, and matching a plurality of fourth point cloud data in the first point cloud data set to the second point cloud data set with a matching degree greater than a predetermined matching degree threshold by a second formula, to obtain a fourth point cloud data set, wherein the second formula is: n represents the nth Gaussian distribution of b θ The optimal matching of c θ is the nth Gaussian distribution of b θ The second point cloud data is determined as background point cloud data in the second point cloud data set, wherein the predetermined relationship is ω i ≥ T, c θ - μ i ≤ 3σn T represents the weight threshold; the portion of the second point cloud data set excluding the background point cloud data is determined as the target point cloud data set.

[0054] Here, i represents the value of i when the natural function is maximized by the nth Gaussian distribution.

[0055] Optionally, the aforementioned predetermined matching threshold is used to find the point cloud data in the second point cloud data set that best matches the third point cloud data under the same scanning angle, so as to improve the detection accuracy.

[0056] Optionally, the above-mentioned predefined relationship is used to determine whether the current point cloud data is background point cloud data.

[0057] For example, when a belt conveyor starts transporting coal, it acquires point cloud data of the current belt conveyor scene through multiple scans using lidar, and processes this data. Specifically, at each scanning angle of the lidar, the distance c of the current point cloud is calculated. θ With b θ Each Gaussian distribution is matched according to the formula. (Second formula) is used to find the optimal matching, where n represents c. θ The optimal match is b θ The nth Gaussian distribution is used to classify the point cloud after determining the optimal match.

[0058] The following is combined Figure 3 The above embodiments will be described in detail below. Figure 3 This is a schematic diagram of point cloud data according to an embodiment of the present invention. The current point cloud data simultaneously satisfies ω... i ≥T、c θ -μ i ≤3σ n When using these two formulas, it can be directly identified as a background point cloud, such as... Figure 3 The background point cloud is marked in the middle; the current point cloud data only satisfies c θ -μ i ≤3σ n When using this formula, it is determined to be a suspected background point cloud, such as... Figure 3 The suspected background point cloud is marked in the middle; other cases are directly marked as target point clouds, such as... Figure 3 As shown, the target point cloud includes coal flow and foreign objects.

[0059] Additionally, when cθ is a background point cloud or a suspected background point cloud, it needs to be calculated according to the formula. (in, Update b θ Each Gaussian distribution weight w' i At the same time, according to μ' n =(1-∝)μn + a c θ and (wherein, a is a learning rate, which can be set to 0.1-0.01) to update the optimal matching Gaussian distribution parameters μ ' n and The remaining parameters do not need to be updated; after updating the conveyor belt profile, the above matching process is returned to, and the cycle is repeated until the background point cloud data and the target point cloud data are accurately separated.

[0060] In order to realize the function of restoring the field of the belt conveyor, all laser point clouds in the time sequence can be spliced to form a high-precision three-dimensional model after triangulation, and all background point clouds and target point clouds are marked according to the above Gaussian modeling method, as shown in the above Figure 3 The background point cloud records the operation scene of the belt conveyor when it is empty, and the point cloud that is obviously different from the background is marked as a target point cloud, and the target point cloud includes the contour of the coal flow and other foreign matters. Through the three-dimensional model, the operation field can be restored realistically, and the abnormal targets in the scene can be marked in a visual form, which greatly reduces the labor cost, avoids the on-site inspection of workers, effectively avoids safety hazards, personal losses and major disasters, and the like.

[0061] In step S208, the position information of the coal flow conveyed by the conveyor belt in the third point cloud data set is determined.

[0062] According to the above embodiment of the present application, in the above step S208, the position information of the coal flow conveyed by the conveyor belt in the third point cloud data set is determined, including: determining the maximum width of the conveyor belt; determining the minimum height difference of the conveyor belt in the empty state and the laser radar; according to the maximum width and the minimum height difference, determining the first angle at which the laser radar starts to scan the coal flow on the conveyor belt by using a fourth formula, and simultaneously determining the second angle at which the laser radar last scans the coal flow on the conveyor belt by using a fifth formula, wherein the fourth formula is: θ s represents the first angle, θ max represents the maximum scanning range of the laser radar, w represents the maximum width, and H represents the minimum height difference; the fifth formula is: θ e represents the second angle; and the position information is determined according to the first angle and the second angle.

[0063] Optionally, the above first angle is the angle at which the laser radar scans the conveyor belt for the first time after starting to scan.

[0064] Optionally, the above second angle is the angle at which the laser radar scans the conveyor belt for the last time after starting to scan.

[0065] The above embodiment will be described in detail below in combination with Figure 4 .Figure 4 is a schematic diagram of the position of the coal flow according to an embodiment of the present application. The maximum width W of the conveyor belt and the minimum height difference H between the laser radar and the belt conveyor when the belt conveyor is empty are measured, and the maximum range of the scanning angle of the laser radar is determined max Then, the first angle at which the laser radar starts scanning the coal flow on the conveyor belt and the second angle at which the laser radar stops scanning the coal flow on the conveyor belt are calculated according to the fourth formula) and the fifth formula), as shown in Figure 4 The angle at which the laser radar first scans the conveyor belt after starting scanning is the first angle s , and the angle at which the laser radar last scans the conveyor belt after starting scanning is the second angle e .

[0066] In step S210, non-coal flow objects within the predetermined range of the belt conveyor are filtered from the target point cloud data set according to the position information of the coal flow.

[0067] In order to accurately calculate the coal flow rate, the belt conveyor foreign object screening method based on laser scanning further comprises: determining the rotational speed of the belt conveyor through an encoder in the belt conveyor; determining the transmission ratio of the speed reducer of the belt conveyor; determining the drum radius and transmission efficiency of the belt conveyor; and determining the running speed of the conveyor belt according to the rotational speed, transmission ratio, drum radius and transmission efficiency through a sixth formula, wherein the sixth formula is: v represents the running speed, l represents the rotational speed, r represents the drum radius, b represents the transmission efficiency, and i represents the transmission ratio; and determining the instantaneous flow rate of the coal flow through a seventh formula, wherein the seventh formula is: V represents the instantaneous flow rate, d represents the angular resolution of the laser radar, s represents the first point at which the coal flow area appears, and e represents the last point at which the coal flow area appears.

[0068] In the high-precision three-dimensional model of the belt conveyor, the coal flow area can also be clearly presented. For the coal flow area, the rotational speed l of the belt conveyor is measured through the encoder, and then the running speed v of the belt conveyor is calculated according to the sixth formula), and then the instantaneous coal flow rate of the belt conveyor can be accurately calculated according to , thereby realizing the function of real-time monitoring of the change in the coal flow rate.

[0069] According to the above embodiment of the present application, after the step S202, that is, after the contour of the conveyor belt of the belt conveyor is determined according to the first point cloud data set, the method further comprises: detecting the conveyor belt according to the contour to determine whether the conveyor belt has a crack; and generating first alarm information when it is determined that the conveyor belt has a crack, wherein the first alarm information is used to prompt that the conveyor belt has a crack.

[0070] In the above embodiment, the conveyor belt is detected according to the contour, and if an abnormal condition such as a crack of the conveyor belt is found, the abnormal condition or fault can be visually presented in the high-precision three-dimensional model of the belt conveyor and alarm indication information (including but not limited to voice broadcast, indicator light flashing, etc.) is issued, so as to remind the manager to find and handle the abnormal condition or fault as soon as possible, so as to avoid further damage to the belt conveyor, thereby affecting the efficiency of coal flow conveying, reducing the service life of the belt conveyor, and the like, and further improving the production efficiency.

[0071] According to the above embodiment of the present application, after the step S210, that is, after the non-coal flow object within the predetermined range of the belt conveyor is filtered out from the target point cloud data set according to the position information of the coal flow, the method further comprises: generating second alarm information, wherein the second alarm information is used to prompt that there is a non-coal flow object within the predetermined range of the belt conveyor.

[0072] In the above embodiment, the non-coal flow object within the predetermined range of the belt conveyor is filtered out from the target point cloud data set according to the position information of the coal flow, and if an abnormality is found, the abnormality can be visually presented in the high-precision three-dimensional model of the belt conveyor and information indication is issued to prompt the staff to clean up in time, so as to ensure the quality of the coal flow, avoid damage to the belt conveyor due to the existence of foreign matters, thereby affecting the efficiency of coal flow conveying, reducing the service life of the belt conveyor, and the like, and further improving the production efficiency.

[0073] From the above, in the embodiment of the present application, through the above steps, the profile of the conveyor belt of the belt conveyor can be determined according to the first point cloud data set first, wherein the first point cloud data set includes a set of point cloud data in the empty state of the conveyor belt; then the second point cloud data set is matched with the third point cloud data set corresponding to the profile according to the scanning angle, and the matching result is obtained; then the target point cloud data set in the second point cloud data set that does not match the third point cloud data set under the same scanning angle is determined according to the matching result; then the position information of the coal flow conveyed by the conveyor belt in the third point cloud data set is determined; finally, the non-coal flow object within the predetermined range of the belt conveyor is screened out from the target point cloud data set according to the position information of the coal flow, which achieves that the profile of the conveyor belt can be generated by using the point cloud data set in the empty state of the conveyor belt, then the point cloud data set collected in the coal flow conveying state is compared with the point cloud data corresponding to the profile of the conveyor belt according to the scanning angle, and the target point cloud data set including the coal flow and foreign matter is obtained, and then the foreign matter other than the coal flow is screened out from the target point cloud data set according to the area where the coal flow appears, that is, the on-site situation of the belt conveyor can be monitored visually, and the non-coal flow object on the belt conveyor is screened out, realizing the automatic screening of the foreign matter on the belt conveyor site, reducing the labor cost, and thus reducing the safety hidden danger.

[0074] Therefore, by the technical scheme provided in the embodiment of the present application, the technical problem that it is difficult to monitor the on-site situation of the belt conveyor and thus difficult to detect the foreign matter due to the monitoring difficulty in the prior art is solved.

[0075] According to the above embodiment of the present application, all laser point clouds in the time sequence are spliced to form a high-precision three-dimensional model after triangulation, that is, three-dimensional modeling is performed based on the point cloud data of laser scanning, which involves a digital twin system of the mine belt conveyor.

[0076] The application of digital twin technology in coal mine production fully plays the role of digital twin technology in realistically replicating the mirror scene of activities such as coal mining, tunneling and transportation, and then holographic physical perception, intelligent monitoring and three-dimensional visual reproduction of the coal mine operation scene, greatly improving the intelligent level of coal mine production, effectively avoiding safety hazards, human losses and major disasters. In coal mine production, the number of equipment and personnel losses caused by belt conveyors is incalculable, and the safety supervision of belt conveyors is seriously lacking. The use of digital twin technology to establish a high-precision mirror scene to realize three-dimensional reproduction of coal transportation scenes, real-time monitoring of transportation trends, diagnosis of abnormal conditions, etc. will become the key to filling the huge gap in the field of belt conveyor transportation supervision.

[0077] In addition, in the embodiment of the application, the main equipment of the belt conveyor digital twin system based on laser scanning and Gaussian mixture includes a high-precision laser radar, a high-performance computing unit, an encoder, and a dustproof and explosion-proof electromagnetic shielding shell. The high-precision laser radar is responsible for holographic perception of the working scene, the computing unit is used for processing and uploading the point cloud data of the laser radar, the encoder is used for obtaining the instantaneous speed of the belt conveyor, and the dustproof and explosion-proof shell can isolate the mutual interference between the system and the working environment.

[0078] Compared with the existing artificial inspection and video monitoring technologies, the Gaussian mixture modeling of the belt conveyor transport scene by using the laser radar can realize the functions of marking abnormal targets, realistically restoring the working site, and monitoring the coal flow changes in real time.

[0079] It should be noted that, for the foregoing method embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited to the action sequence described, because according to the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to preferred embodiments, and the actions and modules involved are not necessarily essential to the present application.

[0080] From the above description of the embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be realized by means of software and the necessary general hardware platform, and of course, it can also be realized by hardware, but in many cases, the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which is stored in a storage medium (such as a ROM / RAM, a magnetic disk, or an optical disk), and includes a plurality of instructions for causing a terminal device (which can be a mobile phone, a computer, a server, or a network device) to execute the methods described in the embodiments of the present application.

[0081] According to the embodiment of the application, a laser scanning based belt conveyor foreign matter screening device for implementing the above laser scanning based belt conveyor foreign matter screening method is also provided, Figure 5 is a schematic diagram of the laser scanning based belt conveyor foreign matter screening device according to the embodiment of the application, as Figure 5 shown, the device includes a first determination unit 51, a matching unit 53, a second determination unit 55, a third determination unit 57, and a screening unit 59. The laser scanning based belt conveyor foreign matter screening device will be described in detail below.

[0082] The first determination unit 51 is configured to determine a contour of a conveyor belt of the belt conveyor according to a first point cloud data set, wherein the first point cloud data set comprises a set of point cloud data in an empty state of the conveyor belt.

[0083] The matching unit 53 is configured to match the second point cloud data set with a third point cloud data set corresponding to the contour according to a scanning angle, to obtain a matching result.

[0084] The second determination unit 55 is configured to determine, according to the matching result, a target point cloud data set in the second point cloud data set that does not match the third point cloud data set in the same scanning angle.

[0085] The third determination unit 57 is configured to determine position information of a coal flow conveyed by the conveyor belt in the third point cloud data set.

[0086] The screening unit 59 is configured to screen a non-coal flow object within a predetermined range of the belt conveyor from the target point cloud data set according to the position information of the coal flow.

[0087] It should be noted that the first determination unit 51, the matching unit 53, the second determination unit 55, the third determination unit 57 and the screening unit 59 correspond to steps S202 to S210 in the above embodiment, and the five units have the same instances and application scenarios as the corresponding steps, but are not limited to the content disclosed in the above embodiment.

[0088] As can be seen from the above, in the scheme described in the above embodiment, the first determination unit is used to determine a contour of a conveyor belt of a belt conveyor according to a first point cloud data set, wherein the first point cloud data set comprises a set of point cloud data in an empty state of the conveyor belt; then the matching unit is used to match the second point cloud data set with a third point cloud data set corresponding to the contour according to a scanning angle, to obtain a matching result; then the second determination unit is used to determine, according to the matching result, a target point cloud data set in the second point cloud data set that does not match the third point cloud data set in the same scanning angle; then the third determination unit is used to determine position information of a coal flow conveyed by the conveyor belt in the third point cloud data set; and finally the screening unit is used to screen a non-coal flow object within a predetermined range of the belt conveyor from the target point cloud data set according to the position information of the coal flow.

[0089] This method achieves the goal of generating the outline of a conveyor belt using point cloud data sets from an unloaded state. Then, it compares the point cloud data sets collected during coal transport with the point cloud data corresponding to the conveyor belt outline according to the scanning angle, obtaining a target point cloud data set including coal flow and foreign objects. Based on the area where coal flow occurs, it filters out foreign objects other than coal flow from the target point cloud data set. In other words, it enables visualized monitoring of the conveyor belt's on-site conditions, filtering out non-coal flow objects on the conveyor belt, realizing automated screening of foreign objects on the conveyor belt, reducing labor costs, and thus reducing safety hazards.

[0090] Therefore, the technical solution provided by the embodiments of the present invention solves the technical problem in the prior art that it is difficult to monitor the on-site conditions of belt conveyors due to monitoring difficulties, thus making it difficult to detect foreign objects. Optionally, the first determining unit includes: an acquisition module, used to trigger a laser radar to perform a predetermined number of scan operations on the conveyor belt when the conveyor belt is in an unloaded state, to obtain a first point cloud data set; a first determining module, used to determine the scanning angle of each point cloud data in the first point cloud data set acquired by the laser radar based on the first point cloud data set; a second determining module, used to determine the initial point cloud distance corresponding to the scanning angle of each point cloud data, to obtain an initial point cloud data set, wherein the point cloud distance represents the vertical distance between the laser radar and the conveyor belt at the scanning angle; and a third determining module, used to determine the contour based on the initial point cloud data set.

[0091] Optionally, the initial point cloud distances satisfy a Gaussian mixture distribution, wherein the Gaussian mixture distribution is expressed by the first formula: b θ θ represents the initial point cloud distance, θ represents the scanning angle, k represents the number of Gaussian distributions, and ω represents the initial point cloud distance. i μ represents the weight of the i-th Gaussian distribution. i b θ The mean of the i-th matching Gaussian distribution, b θ The variance of the i-th matching Gaussian distribution,

[0092] Optionally, the second determining unit includes: a matching module, configured to match each second point cloud data in the second point cloud data set with the Gaussian mixture distribution of each third point cloud data in the third point cloud data set, and to match multiple fourth point cloud data in the first point cloud data set whose matching degree with the second point cloud data set is greater than a predetermined matching degree threshold using a second formula, thereby obtaining a fourth point cloud data set, wherein the second formula is: n represents c θ The optimal match is b θ The nth Gaussian distribution, c θrepresents the second point cloud data; a fourth determining module, configured to determine point cloud data in the fourth point cloud data set that satisfies a predetermined relationship as background point cloud data in the second point cloud data set, where the predetermined relationship is: ω i ≥ T, c θ - μ i ≤ 3σ n , T represents a weight threshold; and a fifth determining module, configured to determine a part of the second point cloud data set excluding the background point cloud data as a target point cloud data set.

[0093] Optionally, the third determining unit comprises: a sixth determining module, configured to determine a maximum width of the conveyor belt; a seventh determining module, configured to determine a minimum height difference between the conveyor belt in an empty state and the laser radar; and an eighth determining module, configured to determine, according to the maximum width and the minimum height difference, a first angle at which the laser radar starts scanning coal flow on the conveyor belt by using a fourth formula, and determine a second angle at which the laser radar stops scanning the coal flow on the conveyor belt by using a fifth formula, where the fourth formula is: θ s represents the first angle, θ max represents a maximum scanning range of the laser radar, w represents the maximum width, and H represents the minimum height difference; and the fifth formula is: θ e represents the second angle; and a ninth determining module, configured to determine position information according to the first angle and the second angle.

[0094] Optionally, the foreign matter screening device for the belt conveyor based on laser scanning further comprises: a tenth determining module, configured to determine a rotating speed of the belt conveyor by using an encoder in the belt conveyor; an eleventh determining module, configured to determine a transmission ratio of a speed reducer of the belt conveyor; a twelfth determining module, configured to determine a drum radius and a transmission efficiency of the belt conveyor; a thirteenth determining module, configured to determine a running speed of the conveyor belt by using a sixth formula according to the rotating speed, the transmission ratio, the drum radius and the transmission efficiency, where the sixth formula is: v = λrβi represents the running speed, λ represents the rotating speed, r represents the drum radius, β represents the transmission efficiency, and i represents the transmission ratio; and a fourteenth determining module, configured to determine an instantaneous flow of the coal flow by using a seventh formula, where the seventh formula is: V = δi represents the instantaneous flow, and δ represents an angle resolution of the laser radar.

[0095] Optionally, the foreign matter screening device for the belt conveyor based on laser scanning further comprises: a fourth determining unit, configured to detect the conveyor belt according to a contour of the conveyor belt determined according to the first point cloud data set, to determine whether a crack occurs in the conveyor belt; and a first generating unit, configured to generate first alarm information when it is determined that the crack occurs in the conveyor belt, where the first alarm information is used to prompt that the crack occurs in the conveyor belt.

[0096] Optionally, the belt conveyor foreign matter screening device based on laser scanning further comprises a second generating unit configured to generate second alarm information after screening out non-coal flow objects within a predetermined range of the belt conveyor from the target point cloud data set according to the position information of the coal flow, wherein the second alarm information is used to prompt that there are non-coal flow objects within the predetermined range of the belt conveyor.

[0097] According to another aspect of the embodiments of the present application, a computer readable storage medium is further provided, and the computer readable storage medium comprises a stored program, wherein the program performs any of the belt conveyor foreign matter screening methods based on laser scanning.

[0098] Optionally, in the embodiment, the computer readable storage medium can be located in any one of the computer terminals in the computer terminal group in the computer network, or in any one of the communication devices in the communication device group.

[0099] Optionally, in the embodiment, the computer readable storage medium is configured to store program codes for performing the following steps: determining the contour of the conveyor belt of the belt conveyor according to the first point cloud data set, wherein the first point cloud data set comprises a set of point cloud data in an empty state of the conveyor belt; matching the second point cloud data set with the third point cloud data set corresponding to the contour according to the scanning angle, to obtain a matching result; determining a target point cloud data set that does not match the third point cloud data set in the second point cloud data set under the same scanning angle according to the matching result; determining the position information of the coal flow conveyed by the conveyor belt in the third point cloud data set; and screening out non-coal flow objects within a predetermined range of the belt conveyor from the target point cloud data set according to the position information of the coal flow.

[0100] Optionally, in the embodiment, the computer readable storage medium is configured to store program codes for performing the following steps: triggering the laser radar to perform a predetermined number of scanning operations on the conveyor belt when the conveyor belt is in an empty state, to obtain the first point cloud data set; determining the scanning angle of the laser radar collecting each point cloud data in the first point cloud data set according to the first point cloud data set; determining the initial point cloud distance corresponding to the scanning angle of each point cloud data, to obtain the initial point cloud data set, wherein the point cloud distance represents the vertical distance between the laser radar and the conveyor belt under the scanning angle; and determining the contour according to the initial point cloud data set.

[0101] Optionally, in the embodiment, the computer readable storage medium is configured to store program codes for performing the following steps: b θ represents the initial point cloud distance, θ represents the scanning angle, k represents the number of Gaussian distributions, ω i represents the weight of the i-th Gaussian distribution, μi the mean of the i th matching Gaussian distribution of b θ the mean of the i th matching Gaussian distribution of b θ

[0102] Optionally, in the embodiment, the computer readable storage medium is configured to store program code for performing the following steps: matching each second point cloud data in the second point cloud data set to a Gaussian mixture distribution of each third point cloud data in the third point cloud data set respectively, and obtaining a fourth point cloud data set by matching, in the first point cloud data set, a plurality of fourth point cloud data with a matching degree greater than a predetermined matching degree threshold to the second point cloud data set by a second formula, wherein the second formula is: θ the optimal matching of b θ is the n th Gaussian distribution of b θ i θ i n T represents a weight threshold; and determining a part of the second point cloud data set other than the background point cloud data as the target point cloud data set.

[0103] Optionally, in the embodiment, the computer readable storage medium is configured to store program code for performing the following steps: determining a maximum width of the conveyor belt; determining a minimum height difference between the conveyor belt in an empty state and the laser radar; determining, according to the maximum width and the minimum height difference, a first angle at which the laser radar starts to scan the coal flow on the conveyor belt by using a fourth formula, and simultaneously determining a second angle at which the laser radar last scans the coal flow on the conveyor belt by using a fifth formula, wherein the fourth formula is: s max θ e represents the second angle; and determining the position information according to the first angle and the second angle.

[0104] ​​​​​​​​​​Optionally, in the embodiment, the computer readable storage medium is configured to store program code for performing the following steps: determining the rotation speed of the belt conveyor by an encoder in the belt conveyor; determining the transmission ratio of the speed reducer of the belt conveyor; determining the drum radius and the transmission efficiency of the belt conveyor; determining the running speed of the belt conveyor according to the rotation speed, the transmission ratio, the drum radius and the transmission efficiency, wherein the sixth formula is: v represents the rotation speed, λ represents the running speed, r represents the drum radius, β represents the transmission efficiency, and i represents the transmission ratio; determining the instantaneous flow of the coal flow by the seventh formula, wherein the seventh formula is: V represents the instantaneous flow, and δ represents the angular resolution of the laser radar.

[0105] Optionally, in the embodiment, the computer readable storage medium is configured to store program code for performing the following steps: detecting the belt conveyor according to the profile to determine whether the belt conveyor has a crack; and generating first alarm information when it is determined that the belt conveyor has a crack, wherein the first alarm information is used to prompt that the belt conveyor has a crack.

[0106] Optionally, in the embodiment, the computer readable storage medium is configured to store program code for performing the following steps: generating second alarm information, wherein the second alarm information is used to prompt that there is a non-coal flow object in a predetermined range of the belt conveyor.

[0107] According to another aspect of the embodiment of the present application, a processor is also provided, and the processor is used to run a program, wherein the program performs any one of the above-mentioned belt conveyor foreign matter screening methods based on laser scanning when the program is running.

[0108] The above-mentioned serial numbers of the embodiments of the present application are only for description, and do not represent the advantages and disadvantages of the embodiments.

[0109] In the above-mentioned embodiments of the present application, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0110] In several embodiments provided in the present application, it should be understood that the disclosed technical contents can be implemented by other ways. Among them, the above-mentioned device embodiments are only schematic, for example, the division of the units can be a logical function division, and actual implementation can have another division way, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed each other can be through some interface, indirect coupling or communication connection between units or modules, which can be electrical or other forms.

[0111] The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0112] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0113] The integrated unit, if realized in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application, essentially or the part that contributes to the prior art, or all or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, including a number of instructions to make a computer device (which can be a personal computer, a server or a network device, etc.) execute all or part of the steps of the method described in each embodiment of the present application. The foregoing storage medium includes: a U disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a mobile hard disk, a magnetic disk or an optical disk, and various program code storage media.

[0114] The above is only the preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for screening foreign objects in a belt conveyor based on laser scanning, characterized in that, include: The outline of the conveyor belt of the belt conveyor is determined based on the first point cloud data set, wherein the first point cloud data set includes the set of point cloud data of the conveyor belt in the unloaded state. The second point cloud data set is matched with the third point cloud data set corresponding to the contour according to the scanning angle to obtain the matching result. The second point cloud data set refers to the point cloud data set obtained by the lidar scanning the scene multiple times after the belt conveyor starts to transport coal. Based on the matching results, a target point cloud data set that does not match the third point cloud data set in the second point cloud data set under the same scanning angle is determined; Determine the location information of the coal flow transported by the conveyor belt in the third point cloud data set; Based on the location information of the coal flow, non-coal flow objects within the predetermined range of the belt conveyor are selected from the target point cloud data set. Determining the location information of the coal flow transported by the conveyor belt in the third point cloud data set includes: determining the maximum width of the conveyor belt; determining the minimum height difference between the conveyor belt in an unloaded state and the lidar; based on the maximum width and the minimum height difference, using a fourth formula to determine the first angle when the lidar begins to scan the coal flow on the conveyor belt, and simultaneously using a fifth formula to determine the second angle when the lidar finally scans the coal flow on the conveyor belt, wherein the fourth formula is: θ s Let θ represent the first angle. max The fifth formula is: w represents the maximum scanning range of the lidar, w represents the maximum width, and H represents the minimum height difference; θ e The second angle is indicated; the position information is determined based on the first angle and the second angle.

2. The method for foreign object screening of a belt conveyor based on laser scanning according to claim 1, characterized in that, The outline of the conveyor belt of the belt conveyor is determined based on the first point cloud data set, including: When the conveyor belt is in an unloaded state, the lidar is triggered to perform a predetermined number of scans on the conveyor belt to obtain the first point cloud data set; The scanning angle for each point cloud data in the first point cloud data set is determined by the lidar based on the first point cloud data set. Determine the initial point cloud distance corresponding to the scanning angle of each point cloud data to obtain an initial point cloud data set, wherein the point cloud distance represents the vertical distance between the lidar and the conveyor belt at the scanning angle; The contour is determined based on the initial point cloud dataset.

3. The method for foreign object screening of a belt conveyor based on laser scanning according to claim 2, characterized in that, The initial point cloud distances satisfy a Gaussian mixture distribution, wherein the Gaussian mixture distribution is expressed by a first formula: b θ The initial point cloud distance is represented by θ, the scanning angle is represented by k, and the Gaussian distribution number is represented by ω. i μ represents the weight of the i-th Gaussian distribution. i b θ The mean of the i-th matching Gaussian distribution, b θ The variance of the i-th matching Gaussian distribution, 4. The method for foreign object screening of a belt conveyor based on laser scanning according to claim 3, characterized in that, Based on the matching results, a target point cloud data set that does not match the third point cloud data set within the second point cloud data set at the same scanning angle is determined, including: Each second point cloud data in the second point cloud data set is matched with the Gaussian mixture distribution of each third point cloud data in the third point cloud data set. Then, multiple fourth point cloud data in the first point cloud data set whose matching degree with the second point cloud data set is greater than a predetermined matching degree threshold are matched using a second formula, thus obtaining the fourth point cloud data set. The second formula is: n represents c θ The optimal match is b θ The nth Gaussian distribution, c θ This refers to the second point of cloud data; Point cloud data in the fourth point cloud data set that satisfy a predetermined relationship are identified as background point cloud data in the second point cloud data set, wherein the predetermined relationship is: ω i ≥T, c θ -μ i ≤3σ n T represents the weight threshold; The portion of the second point cloud data set excluding the background point cloud data is determined to be the target point cloud data set.

5. The method for foreign object screening of a belt conveyor based on laser scanning according to claim 4, characterized in that, Also includes: The rotational speed of the belt conveyor is determined by an encoder inside the belt conveyor. Determine the transmission ratio of the reducer of the belt conveyor; Determine the roller radius and transmission efficiency of the belt conveyor; The operating speed of the conveyor belt is determined by a sixth formula based on the rotational speed, the transmission ratio, the roller radius, and the transmission efficiency. The sixth formula is: v represents the operating speed, λ represents the rotational speed, r represents the drum radius, β represents the transmission efficiency, and i represents the transmission ratio; The instantaneous flow rate of the coal stream is determined by the seventh formula, wherein the seventh formula is: V represents the instantaneous flow rate, δ represents the angular resolution of the lidar, s represents the first point where the coal flow region begins to appear, and e represents the last point where the coal flow region appears.

6. The method for foreign object screening of a belt conveyor based on laser scanning according to claim 1, characterized in that, After determining the outline of the conveyor belt of the belt conveyor based on the first point cloud data set, the process also includes: The conveyor belt is inspected according to the outline to determine whether there are cracks in the conveyor belt; When a crack is detected in the conveyor belt, a first alarm message is generated, wherein the first alarm message is used to indicate that a crack has occurred in the conveyor belt.

7. The method for foreign object screening of a belt conveyor based on laser scanning according to claim 1, characterized in that, After filtering out non-coal flow objects within a predetermined range of the belt conveyor from the target point cloud data set based on the location information of the coal flow, the method further includes: A second alarm message is generated, wherein the second alarm message is used to indicate that the non-coal flow object exists within a predetermined range of the belt conveyor.

8. A foreign object screening device for a belt conveyor based on laser scanning, characterized in that, include: The first determining unit is used to determine the outline of the conveyor belt of the belt conveyor based on the first point cloud data set, wherein the first point cloud data set includes a set of point cloud data of the conveyor belt in an unloaded state. The matching unit is used to match the second point cloud data set with the third point cloud data set corresponding to the contour according to the scanning angle, and obtain the matching result. The second point cloud data set refers to the point cloud data set obtained by the lidar scanning the scene multiple times after the belt conveyor starts to transport coal. The second determining unit is used to determine, based on the matching result, a target point cloud data set in the second point cloud data set that does not match the third point cloud data set under the same scanning angle; The third determining unit is used to determine the location information of the coal flow transported by the conveyor belt in the third point cloud data set; The filtering unit is used to filter out non-coal flow objects within a predetermined range of the belt conveyor from the target point cloud data set based on the location information of the coal flow. The third determining unit includes: The sixth determining module is used to determine the maximum width of the conveyor belt; The seventh determining module is used to determine the minimum height difference between the conveyor belt and the lidar when the conveyor belt is unloaded; The eighth determining module is used to determine, based on the maximum width and the minimum height difference, the first angle at which the lidar begins scanning the coal flow on the conveyor belt using a fourth formula, and simultaneously to determine the second angle at which the lidar last scans the coal flow on the conveyor belt using a fifth formula, wherein the fourth formula is: θ s Let θ represent the first angle. max The fifth formula is: w represents the maximum scanning range of the lidar, w represents the maximum width, and H represents the minimum height difference; θ e Indicates the second angle; The ninth determining module is used to determine the position information based on the first angle and the second angle.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein the program executes the laser scanning-based foreign object screening method for belt conveyors as described in any one of claims 1 to 7.

10. A processor, characterized in that, The processor is used to run a program, wherein the program executes the laser scanning-based foreign object screening method for belt conveyors according to any one of claims 1 to 7.

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