Three-dimensional detection method and device using multi-point laser ranging

Abstract

The invention relates to the technical field of three-dimensional detection, in particular to a three-dimensional detection method and device using multi-point laser ranging, and the method comprises the steps: fixing a detection body which is provided with a plurality of detection layers which gradually change according to certain distance indexing on an object to be detected, a detection surface is in a ball, ellipse or cone shape and has the characteristic of gradually changing according to certain distance indexing, laser rangefinders are arranged at corresponding positions of the detection surface according to certain distances, multi-point measurement light spots respectively detect distance data of all points of the detection surface, and distance values of all the points generate unique position IDs according to a set sequence; and the three-dimensional coordinates of the measured object are calculated by combining the fixed geometric space relationship of each detection point and are compared with the initial coordinates, the three-dimensional displacement vector is calculated, and the corresponding device comprises a detection part, a laser ranging part and a processing part. The multi-layer detection structure is combined with the laser ranging device, two ranging modes of single-point scanning and multi-point synchronization are supported, the structure is simple, deployment is convenient, and adaptability is high.

Description

Technical Field

[0001] This invention relates to the field of three-dimensional detection technology, specifically to a three-dimensional detection method and apparatus utilizing multi-point laser ranging. Background Technology

[0002] In fields such as machining, precision assembly, structural health monitoring (e.g., deformation detection of bridges and buildings), automation control, and robot positioning, accurate, real-time, and non-contact detection of the position, displacement, or orientation of objects in three-dimensional space is a crucial core requirement.

[0003] Currently, the existing technologies for achieving 3D inspection mainly include the following categories: Contact measurement: such as coordinate measuring machines (CMMs) and dial indicators. This type of technology obtains coordinate points by directly contacting the surface of the object being measured with a physical probe. Its advantages are high measurement accuracy; however, its disadvantages are also very obvious: complex deployment, requiring a stable measurement environment and professional operators, slow measurement speed, unable to meet dynamic or online inspection needs, and as a contact measurement, it may cause scratches on soft surfaces or errors due to measurement forces. The system is also bulky, expensive, and difficult to deploy flexibly in industrial sites, and cannot achieve online automatic inspection.

[0004] Visual measurement systems, such as 3D reconstruction and photogrammetry based on monocular, binocular, or multi-view cameras, calculate the 3D information of objects by analyzing captured images or video sequences. Their advantages include non-contact operation and rich information, but they also have the following problems and disadvantages: poor environmental adaptability, sensitivity to changes in ambient lighting, severe performance degradation in low light, strong light, or uneven lighting conditions, susceptibility to occlusion interference (measurement fails if target feature points are occluded), complex calculations, high hardware computing power requirements for real-time processing of high-definition image data, and significant system latency; cumbersome calibration process requiring multiple steps, and insufficient ease of deployment and maintenance; these cameras cannot achieve 3D detection, generally only completing one-dimensional depth of field, requiring detection in three directions to achieve 3D detection.

[0005] Multi-sensor discrete combination measurement: For example, using three single-axis laser displacement sensors to measure the displacement of an object in the X, Y, and Z directions can achieve non-contact measurement to a certain extent. However, its main drawbacks are: complex system integration, requiring precise installation and calibration of multiple independent sensors to ensure that their measurement axes are strictly orthogonal and intersect at the measured point, high deployment difficulty, high cost, and the total cost is increased due to multiple sensors and supporting installation and adjustment mechanisms. The data lacks internal correlation verification, the measurement data in the three directions are independent of each other, and it is impossible to effectively identify and filter erroneous data caused by the temporary obstruction or interference of a single sensor by foreign objects. The anti-interference ability is weak, the risk of false alarm is high, and it is limited by space, as many scenarios do not have the detection space in three directions.

[0006] Therefore, a three-dimensional detection method and device utilizing multi-point laser ranging are needed to improve the above-mentioned problems. Summary of the Invention

[0007] The purpose of this invention is to provide a three-dimensional detection method and apparatus using multi-point laser ranging to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A three-dimensional detection method utilizing multi-point laser ranging includes the following steps: The detector is fixed on the object to be tested. The detector surface is spherical, elliptical or conical and has a feature of gradually changing at a certain distance. It is composed of multiple detection layers of different heights, and each group of detection layers has a feature of gradually changing at a certain distance.

[0009] Laser rangefinders are set up at multiple points according to a certain positional relationship, and fixed at a reference position independent of the object to be measured. The multiple measuring light spots emitted by them can respectively cover multiple detection points on the object to be measured.

[0010] The laser rangefinder uses multiple measuring spots to detect the distance data of each point.

[0011] Based on multiple first distance data and the known fixed geometric spatial relationship between multiple detection points, a feature information used to uniquely characterize the position state of the detection body in a preset direction is calculated and generated as a position ID.

[0012] Based on the location ID and the spatial positional relationship model between the laser rangefinder and the detection object established through calibration, the three-dimensional spatial coordinates of the detection object relative to the laser rangefinder are calculated. The three-dimensional spatial coordinates include the Z-axis component corresponding to the height direction, and the X-axis and Y-axis horizontal components orthogonal to the Z-axis.

[0013] Record the initial position ID and initial three-dimensional coordinates of the detection object when it is in its initial state.

[0014] In subsequent detection, the current position ID and current three-dimensional coordinates are obtained and compared with the initial position ID and initial three-dimensional coordinates to calculate the displacement vectors of the object under test in the three directions of X-axis, Y-axis and Z-axis.

[0015] As a preferred embodiment of the present invention, the step of calculating and generating a location ID based on multiple first distance data and a known fixed geometric relationship between multiple detection points specifically includes: calculating the combination of differences between each first distance data, and the combination of differences constitutes the location ID.

[0016] By calculating the difference between various distance data to generate a location ID, common mode error is effectively eliminated, and the stability and uniqueness of feature information are improved. The difference operation itself has the effect of dimensionality reduction and normalization, which reduces the complexity of subsequent coordinate calculation and improves real-time performance.

[0017] As a preferred embodiment of the present invention, the laser rangefinder is a single-point laser rangefinder sensor integrated with a scanning mechanism.

[0018] The specific steps for acquiring multiple first distance data are as follows: controlling the scanning mechanism to drive the laser beam to scan sequentially in time order and measuring the distance to each of the detection points.

[0019] Using a single-point laser sensor combined with a scanning mechanism to achieve multi-point measurement, the cost is significantly reduced compared to multi-channel synchronous sensors. It is suitable for static or quasi-static detection scenarios where real-time requirements are not high. The single-point scanning mode facilitates optical system calibration and maintenance, making it suitable for occasions where space is limited or the installation angle needs to be dynamically adjusted.

[0020] As a preferred embodiment of the present invention, the laser rangefinder is a synchronous laser rangefinder sensor with multiple independent ranging channels.

[0021] Multi-channel synchronous measurement can achieve data acquisition at millisecond or even higher frequencies, making it suitable for real-time monitoring of high-speed moving objects or vibrating environments. Synchronous acquisition avoids measurement timing errors caused by object movement, thus improving dynamic measurement performance.

[0022] The specific steps for acquiring multiple first distance data are as follows: synchronously measuring the distance to the corresponding detection point through each ranging channel.

[0023] As a preferred embodiment of the present invention, the detection body is a rigid component integrally formed, and its shape is spherical, elliptical or conical, and the detection points on its surface are detection points with different depths, different inclination angles or different heights formed by processing.

[0024] The one-piece molding structure avoids errors caused by assembly gaps or material deformation, ensuring that the geometric relationship between detection points remains constant throughout the entire life cycle. It is suitable for harsh industrial environments such as high and low temperatures and humidity changes, maintaining the consistency of measurement standards.

[0025] As a preferred embodiment of the present invention, the detection body is detachably fixed to the object to be tested by a magnetic attraction structure, adhesive layer or mechanical clamp provided on its back side.

[0026] It supports quick installation and removal via magnetic attraction, bonding, or clamping, making it easy to reuse on test objects of different materials and curved surfaces, improving system applicability and engineering convenience. The non-invasive fixing method avoids damage to the surface of the test object.

[0027] As a preferred embodiment of the present invention, the spatial position relationship model is established through the following calibration steps: The detection body is controlled to be in multiple different known positions relative to the laser rangefinder.

[0028] At each location, obtain multiple sets of first distance data.

[0029] The model is established based on multiple sets of distance data, known location coordinates, and the fixed geometric relationship of the detection points through a parameter fitting algorithm.

[0030] By fitting data from multiple known locations to establish a model, the reliance on operator experience is significantly reduced, improving calibration efficiency and consistency.

[0031] As a preferred embodiment of the present invention, a data verification step is also included: comparing the relative spatial relationship between detection points calculated based on the current distance data with a known fixed geometric relationship.

[0032] If the deviation exceeds the allowable range, the data is deemed invalid or subject to interference.

[0033] By comparing the measured geometric relationships with the theoretical relationships, invalid data caused by occlusion, contamination or transient interference can be automatically identified, improving output reliability, supporting online monitoring and fault early warning, and facilitating system maintenance and status management.

[0034] A three-dimensional detection apparatus for implementing any one of the three-dimensional detection methods, comprising: The detection point is fixed on the object to be tested. The detection point has a surface composed of multiple detection layers of different heights. Each detection layer has a feature of gradually changing at a certain distance. Each group of detection layers includes multiple detection points.

[0035] A multi-point laser ranging component is used to set up on an independent reference position. It has multiple ranging channels so that each measuring spot can cover each detection point on the detection point component.

[0036] The processing unit communicates with the multi-point laser ranging unit to receive distance data from each channel.

[0037] The location ID is generated based on the distance data and the known fixed geometric relationships between the detection points.

[0038] Based on the location ID and the pre-stored spatial position relationship model, the three-dimensional coordinates of the detection point are calculated.

[0039] The displacement vector is calculated and output by comparing the current 3D coordinates with the initial 3D coordinates.

[0040] As a preferred embodiment of the present invention, the processing component is integrated into the control unit of the laser ranging component, or is an external independent computing device connected to the laser ranging component via wired or wireless communication.

[0041] Through the above technical solution, the processing component can be integrated into the control unit of the laser ranging component, or it can be connected as an external independent computing device via wired or wireless means, which takes into account both the system integration and the flexibility of computing resources, and makes it easy to select and optimize between embedded real-time processing and remote high-performance computing according to the actual application scenario.

[0042] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention only requires fixing a compact detection body to the object to be measured and installing a laser ranging device in an appropriate position. It eliminates the need for complex multi-sensor array setup, strict orthogonal calibration, or cumbersome optical calibration procedures, greatly reducing the difficulty of on-site deployment and installation time. The detection body can be quickly fixed and disassembled by magnetic attraction, adhesive, etc., and the laser ranging device can also be flexibly set up, enabling this technology to be quickly applied to a variety of different detection scenarios.

[0043] 2. The detection body of the present invention is usually designed as a rigid integral structure, and the geometric relationship between its detection points is fixed during manufacturing, which ensures the long-term stability and consistency of the measurement benchmark and avoids errors caused by loosening or deformation of components.

[0044] 3. By providing two selectable ranging modes, "single-point scanning" and "multi-point synchronization", and combining them with a modular data processing design, this invention achieves the effect of flexible configuration according to real-time requirements, accuracy needs and cost constraints, thereby achieving a high degree of adaptability with the best balance between performance and cost.

[0045] 4. By utilizing the inherent fixed geometric relationship of the detection body, multiple one-dimensional ranging values ​​are fused and calculated, and an inherent constraint and verification mechanism between data is established, which improves the anti-interference ability and data reliability, and effectively reduces the false alarm rate. Attached Figure Description

[0046] Figure 1 This is a flowchart of the three-dimensional detection method of the present invention; Figure 2 This is a comparison diagram of the two ranging modes of the present invention; Figure 3 This is a schematic diagram of the three-dimensional detection device of the present invention; Figure 4 This is a schematic diagram of the structure of the detector of the present invention.

[0047] Among them, 1. Detection plate; 2. Stepped groove. Detailed Implementation

[0048] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0049] To facilitate understanding of the present invention, a more comprehensive description of the invention will be given below with reference to the accompanying drawings, and several embodiments of the invention will be provided. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the invention will be more thorough and complete.

[0050] It should be noted that the detection body described in this invention is not limited to the specific shape (such as a square pyramid, a hemisphere, etc.) shown in the embodiments. It can also be a sphere, an ellipse, or other cone shape, as long as its surface has multiple detection layers of different heights and the layers have a feature of gradually changing at a certain distance.

[0051] Example 1, please refer to Figure 1-4 This embodiment uses a square pyramid shape as an example for illustration. In practical applications, the detection body can also be a sphere, an ellipse, or other cone shapes. This invention provides a technical solution: a three-dimensional detection method using multi-point laser ranging. It requires preparing and setting up a physical device to implement the method of this invention. The device mainly includes a detection body and a laser ranging device, and includes the following steps: like Figure 4 As shown, the preparation and fixation of the detection body: In this embodiment, the detection body is a one-piece molded metal block. On the measuring surface of the metal block, the four sides of the detection body are processed into a four-sided pyramid shape and fixed to the object to be measured, forming four sets of reflective surfaces in different directions. Each set of reflective surfaces is processed with stepped grooves, and each stepped groove forms a step surface that constitutes a detection point. These four sets of reflective surfaces in different directions are arranged along a preset direction, and the height of each step surface is processed to different known fixed values, for example, the heights are 1.0mm, 3.0mm and 6.0mm, so that the corresponding detection points have different distances relative to the mounting bottom surface of the detection body. The step surfaces are polished and treated with high reflectivity. The detection body is adsorbed onto the metal surface of the object to be measured (such as the spindle box of a machine tool) through the magnetic base at its bottom.

[0052] Installation of the laser rangefinder: Select a single-point laser rangefinder based on the time-of-flight principle. This rangefinder integrates a scanning module that can control the direction of the laser beam, such as a galvanometer. Install this laser rangefinder in a stable position, such as on a device base, using a bracket. Adjust its installation angle to ensure that its laser beam can illuminate all the detection points of the object fixed on the object to be measured through scanning.

[0053] A three-dimensional detection method utilizing multi-point laser ranging is implemented in the following steps: Initial calibration is performed after the detection object and laser rangefinder are installed and a spatial relationship model is established. The operator controls the scanning module of the laser rangefinder to precisely aim the laser beam at all detection points on the four reflective surfaces of the detection object, measuring and recording three initial distance values. , , .

[0054] At this point, it is necessary to determine an initial position of the object to be detected in space (as a reference). This can be obtained by measuring with an external measuring tool (such as an optical tracker). In a preferred manner, this is achieved by placing the object to be detected in a known, fixed initial position.

[0055] Then, the position or orientation of the object under test is slightly altered (or a thin sheet of known thickness is placed under the base of the object to be measured), thus placing the object in a different position. The laser rangefinder is then controlled to scan and measure again, obtaining a new set of distance values. , , And record the new location.

[0056] Repeat this process multiple times to obtain multiple sets of data. Using these data, a set of transformation parameters can be calculated through mathematical fitting methods (such as the least squares method), forming a mathematical model. This model can describe that for any set of three distance values ​​measured by the laser ranging device from the specific detection object, the three-dimensional spatial coordinates of the detection object relative to the laser ranging device can be calculated, which is the calibrated spatial position relationship model. This model is stored in the processing unit (such as an industrial control computer) connected to the laser ranging device. Perform 3D position detection. During routine detection after calibration, perform the following operations: Acquiring distance data: Control the laser rangefinder so that its scanning module drives the laser beam to quickly sweep across all detection points on the detection object in sequence, and simultaneously record the current distance measurement value to each detection point. , , .

[0057] Determine feature information: The processing unit receives all the above distance values, and based on the distance values ​​and their variation relationships, combined with the known geometric positional relationships between each detection point (fixed depth difference and horizontal spacing), performs calculations. , Due to the different depths of the detection points, and The combination formed can uniquely characterize the position of the detected object at the current moment along the preset direction (i.e., the direction in which the detection points are arranged), and this combination is the feature information.

[0058] Solve the 3D coordinates: extract the current distance data ( , , ) and the calculated feature information ( , The data are input together into the spatial position relationship model established in step one. After calculation, the model outputs the three-dimensional spatial coordinates (X,Y,Z) of the detected object relative to the laser ranging device at the current moment. The X-axis component corresponds to the preset direction, and the Y and Z-axis components are orthogonal to the X-axis, which together describe the spatial position.

[0059] To calculate the three-dimensional displacement vector, if displacement needs to be measured, the initial feature information and initial position coordinates of the object to be detected are recorded during the initial calibration. In each subsequent detection, the current feature information and current position coordinates are compared with the initial values, and the displacement of the object in the X, Y, and Z directions is directly obtained through vector subtraction. , , ).

[0060] like Figure 3 As shown, the detection point is fixed on the object to be measured. Its surface has a multi-layered detection layer with varying graduations, a multi-point laser ranging component installed at an independent reference position, used to emit measurement light spots to the detection point and receive reflected signals to obtain distance data from multiple detection points, and a processing component. The processing component is connected to the laser ranging component through a communication interface (wired or wireless), and is responsible for receiving distance data, executing algorithms such as generating position IDs, calling spatial position models to calculate three-dimensional coordinates, calculating displacement vectors, and outputting results. This clarifies the signal flow and functional coordination relationship between the various physical components of the device.

[0061] A three-dimensional detection device utilizing multi-point synchronous laser ranging includes: Inspection point component: This component is a miniaturized hemisphere, integrally injection molded from engineering plastic. Four miniature pyramidal prisms are embedded on its spherical surface as optical markers. The distribution and normal directions of these four prisms on the spherical surface are fixed and known during the design and manufacturing process.

[0062] Laser ranging component: This component is a multi-point synchronous laser ranging sensor based on the phase comparison principle. It contains four independent ranging channels. The optical system of each channel is independent and can emit and receive lasers simultaneously. During installation, the position of the sensor is adjusted so that its four laser spots can be aligned with the four corner prisms on the detection point.

[0063] Processing component: This component, with an embedded processor at its core, is integrated into the housing of the laser rangefinder sensor and is used for real-time data processing.

[0064] After the device is powered on, its laser ranging component emits lasers synchronously through its four channels and receives signals returned from the four corner prisms, thereby simultaneously measuring four distance values.

[0065] The built-in algorithm of the processing unit (i.e., the pre-stored spatial solution model) immediately begins to work. The algorithm takes five synchronous ranging values ​​and the known geometric relationship of five laser emission directions as input. Through spatial geometric optimization calculations, the algorithm finds an optimal position in space for the detection point (the relative relationship of its four prisms is known) such that the overall error between the four calculated distance values ​​and the four actually measured distance values ​​is minimized at this position. This optimal position contains the three-dimensional spatial coordinates (X, Y, Z) of the detection point. The device can repeat this process at an extremely high frequency (e.g., thousands of times per second) to achieve three-dimensional trajectory tracking of dynamic targets.

[0066] Example 2, please refer to Figure 1-3 The method and apparatus described in Example 1 are applied to bridge health monitoring.

[0067] Multiple detection bodies, as described in Example 1, are installed on the bridge deck or beams at several key sections of the bridge (such as mid-span and near supports). A laser ranging device, as described in Example 1, is installed on a stable reference pier near the bridge. The laser ranging device is programmed to automatically scan and monitor each distant detection body in sequence. The processing unit calculates the measurement data of each detection body to obtain its three-dimensional coordinates. By comparing the changes in the coordinates of each point over a long period, the overall settlement, torsional deformation, and dynamic deflection of the bridge can be analyzed, realizing structural safety monitoring based on three-dimensional position detection.

[0068] like Figure 1As shown, the complete logical flow of the three-dimensional detection method of the present invention is clearly demonstrated. The process begins with the detection body fixed to the object to be measured. The detection body has multiple detection surfaces with varying degrees of graduation. Subsequently, a laser rangefinder is set at an independent reference position to ensure that its measurement spot covers multiple detection points on the detection body. The core data processing flow includes: acquiring distance data of each point, calculating and generating feature information (position ID) and verifying the validity of the feature model, and an optional data verification step, which compares the calculated relationship between detection points with the known fixed geometric relationship. If the deviation exceeds the limit, the data is deemed invalid. Then, the three-dimensional coordinates are calculated based on the position ID and the spatial position model. The calculation of the position ID, such as the distance difference combination, utilizes the known fixed geometric relationship between the detection points, while the spatial position model needs to be established through prior calibration. Finally, by recording the initial coordinates and comparing and calculating the displacement vector, the accurate measurement of the three-dimensional displacement of the object to be measured is achieved, clarifying the sequential relationship from data acquisition and feature extraction to coordinate calculation and displacement analysis.

[0069] Example 3: Please refer to Figure 1-3 A bridge bearing three-dimensional displacement online monitoring system based on location ID.

[0070] Preparation and installation of the detection points: The detection plate is made of corrosion-resistant aluminum alloy and machined in one piece using a CNC machine tool to ensure its rigidity and long-term dimensional stability. The plate dimensions are 80mm*50mm*10mm. Three stepped grooves with a depth of 8mm are machined on its measuring surface as high-reflectivity detection points. The centers of the three stepped grooves are strictly aligned with the predetermined direction of the plate, corresponding to the vertical Z-axis of the bridge, and are evenly spaced. Through measurement, the depths of the bottom of the three stepped grooves relative to the mounting surface of the detection plate are known and fixed, namely d1=1.5mm, d2=4.0mm, and d3=7.5mm. A strong magnet is installed on the back of the detection plate, allowing it to be directly attached and fixed to the steel plate on top of the bridge support.

[0071] Deployment of the laser ranging component: A multi-point synchronous laser ranging sensor with three independent ranging channels based on the phase comparison principle was selected as the ranging component. It was installed on a reinforced concrete observation pier integrally cast with the bridge pier, which was considered a stable spatial reference. The pitch and yaw angles of the sensor were adjusted by a high-precision gimbal so that the three laser spots could be stably and clearly projected onto the three concave reflection areas of the detection plate, with an installation distance of approximately 5m.

[0072] System initialization and calibration (model building): After initial installation, execute the calibration process. When the bridge is initially stationary (e.g., at night with no traffic), record the three initial distance values ​​read by the distance measuring sensor at this time. , , And using external measuring equipment such as a total station, the initial three-dimensional coordinates of the detection plate in the distance measuring device coordinate system at this moment are accurately measured. , , This is stored in the processing unit as the "initial position ID" and "initial 3D coordinates".

[0073] To establish a more robust spatial relationship model, several standard shims of known thickness can be temporarily inserted into the bottom of the detection plate to artificially simulate its minute displacement in three axes. Multiple sets (e.g., 10 sets) of distance data and corresponding actual coordinate changes at different positions can be collected. Using these data sets, the transformation matrix parameters that map the distance data and position IDs to three-dimensional coordinates are calculated through least squares fitting, thus completing the model calibration.

[0074] Real-time monitoring and displacement calculation process: After entering monitoring mode, the multi-point laser rangefinder synchronously collects three distance data points at a frequency of 20 times per second. , , ).

[0075] The embedded processing unit (in this embodiment, an industrial computer integrated within the sensor housing) executes the following algorithm in real time: Data reception and verification: Receive three distance values ​​and immediately calculate the difference. , ,Will( , The data is compared with the initial difference and tolerance range stored during calibration. If the difference exceeds the range, the data is marked as suspicious, thus achieving data verification.

[0076] Generate location ID: ( , The combination of these elements serves as the "location ID" for the current moment.

[0077] Solve the 3D coordinates: use the current distance data ( , , ) and location ID ( , Substitute the calibrated spatial position relationship model into the real-time calculation of the current three-dimensional coordinates (X,Y,Z) of the detection board.

[0078] Calculate the displacement vector: compare the current coordinates (X,Y,Z) with the initial coordinates (...). , , Subtracting these values, we obtain the displacement of the bridge support at the current moment relative to its initial state in the longitudinal (X), lateral (Y), and vertical (Z) directions. , , ).

[0079] Data output and application: The processing unit uploads real-time displacement data to the remote monitoring center via the network. The monitoring software can plot displacement / time curves and set multi-level alarm thresholds. Once the displacement in any direction exceeds the set value, the system will automatically trigger an alarm, providing accurate data support for the preventive maintenance of the bridge.

[0080] like Figure 2 As shown, this invention supports two laser ranging modes. The left side is the single-point scanning mode, which uses a single laser ranging sensor and an integrated scanning mechanism (such as a galvanometer). The scanning mechanism drives the laser beam to scan and illuminate detection points at different heights on the detection object in a preset time sequence. Multi-point distance measurement is achieved through time-division multiplexing. The right side is the multi-point synchronous mode, which uses a synchronous laser ranging sensor with multiple independent ranging channels. The sensor emits multiple laser beams simultaneously, which synchronously measure the distance to the corresponding detection points on the detection object. The two modes can be flexibly selected and configured according to the different requirements of real-time performance, cost, and system complexity in the detection scenario.

[0081] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A three-dimensional detection method utilizing multi-point laser ranging, characterized in that, Includes the following steps: The detector is fixed on the object to be tested. The detector surface is spherical, elliptical or conical and has a feature of gradually changing according to a certain distance. It is composed of multiple detection layers of different heights, and each group of detection layers has a feature of gradually changing according to a certain distance. Laser rangefinders are set up at multiple points according to a certain positional relationship, and fixed at a reference position independent of the object to be measured. The multiple measuring light spots emitted by them can respectively cover multiple detection points on the object to be measured. The laser rangefinder uses multiple measuring spots to detect the distance data of each point. Based on multiple first distance data and the known fixed geometric spatial relationship between multiple detection points, feature information used to uniquely characterize the position state of the detected object in a preset direction is calculated and generated as the position ID; Based on the location ID and the spatial positional relationship model between the laser rangefinder and the detection body established through calibration, the three-dimensional spatial coordinates of the detection body relative to the laser rangefinder are calculated. The three-dimensional spatial coordinates include the Z-axis component corresponding to the height direction, and the X-axis and Y-axis horizontal components orthogonal to the Z-axis. Record the initial position ID and initial three-dimensional coordinates of the detection object when it is in its initial state; In subsequent detection, the current position ID and current three-dimensional coordinates are obtained and compared with the initial position ID and initial three-dimensional coordinates to calculate the displacement vectors of the object under test in the three directions of X-axis, Y-axis and Z-axis.

2. The three-dimensional detection method using multi-point laser ranging according to claim 1, characterized in that: The steps for calculating and generating a location ID based on multiple first distance data and known fixed geometric relationships between multiple detection points specifically include: calculating the combination of differences between each first distance data, wherein the combination of differences constitutes the location ID.

3. The three-dimensional detection method using multi-point laser ranging according to claim 1, characterized in that: The laser rangefinder is a single-point laser rangefinder sensor integrated with a scanning mechanism; The specific steps for acquiring multiple first distance data are as follows: controlling the scanning mechanism to drive the laser beam to scan and measure the distance to each detection point in chronological order.

4. The three-dimensional detection method using multi-point laser ranging according to claim 1, characterized in that: The laser rangefinder is a synchronous laser rangefinder sensor with multiple independent ranging channels; The specific steps for acquiring multiple first distance data are as follows: synchronously measuring the distance to the corresponding detection point through each ranging channel.

5. A three-dimensional detection method using multi-point laser ranging according to claim 1, characterized in that: The detection body is a rigid component formed in one piece, and its shape is spherical, elliptical or conical. The detection points on its surface are detection points with different depths, angles or heights formed by processing.

6. A three-dimensional detection method using multi-point laser ranging according to claim 5, characterized in that: The detection body is detachably fixed to the object to be tested by a magnetic structure, adhesive layer or mechanical clamp provided on its back.

7. A three-dimensional detection method using multi-point laser ranging according to claim 1, characterized in that, The spatial location relationship model is established through the following calibration steps: The detection body is controlled to be in multiple different known positions relative to the laser rangefinder; At each location, obtain multiple sets of first distance data. The model is established based on multiple sets of distance data, known location coordinates, and the fixed geometric relationship of the detection points through a parameter fitting algorithm.

8. A three-dimensional detection method using multi-point laser ranging according to claim 1, characterized in that: It also includes a data verification step: comparing the relative spatial relationship between detection points calculated based on the current distance data with the known fixed geometric relationship; If the deviation exceeds the allowable range, the data is deemed invalid or subject to interference.

9. A three-dimensional detection apparatus for implementing the three-dimensional detection method as described in any one of claims 1 to 8, characterized in that, include: The detection point is fixed on the object to be tested. The detection point has a surface composed of multiple detection layers of different heights. Each detection layer has a feature of gradually changing at a certain distance. Each group of detection layers includes multiple detection points. A multi-point laser ranging component is used to set up on an independent reference position. It has multiple ranging channels so that each measuring spot can cover each detection point on the detection point component. The processing unit is communicatively connected to the multi-point laser ranging unit and receives distance data from each channel; Generate location IDs based on distance data and known fixed geometric relationships between detection points; Based on the location ID and the pre-stored spatial position relationship model, the three-dimensional coordinates of the detection point are calculated; The displacement vector is calculated and output by comparing the current 3D coordinates with the initial 3D coordinates.

10. A three-dimensional detection device according to claim 9, characterized in that: The processing component is integrated into the control unit of the laser ranging component, or it is an external independent computing device connected to the laser ranging component via wired or wireless communication.

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