Three-dimensional laser scanner and real-time point cloud scanning method and system

Abstract

The invention relates to the technical field of three-dimensional point cloud scanning, and discloses a three-dimensional laser scanner and a real-time point cloud scanning method and system, and the method comprises the following steps: setting a dot spacing, setting the rotating speed of a drive motor, and setting the transmitting frequency of a laser transmitting and receiving module; controlling the motor to rotate to drive the laser to emit laser; when laser starts to be emitted, the reading module collects angle parameters of the coded disc in real time and measures a laser flight time value through the laser flight time measuring module; combining the angle parameter, the laser flight time value and the laser reflection intensity value read in the last time of laser emission into a frame of data and storing the frame of data in an original data buffer area; reading frame data of the original data buffer area in real time, and calculating to obtain a three-dimensional coordinate; and taking the three-dimensional coordinates and the laser reflection intensity value as a frame of data and storing the frame of data in a result buffer area. The problem that the real-time application requirement is difficult to meet in the prior art is solved, and the method has the advantage of being capable of reducing the operand.

Description

Technical Field

[0001] The present invention relates to the field of three-dimensional point cloud scanning technology, and more specifically, to a three-dimensional laser scanner, a real-time point cloud scanning method and a system. Background Art

[0002] 3D laser scanning technology generates 3D point cloud data of target objects by emitting lasers and measuring their reflection time and angle. It is widely used in architectural surveying, cultural heritage protection, autonomous driving and other fields. However, traditional equipment takes a long time to complete the scan and cannot meet the needs of real-time applications. Point cloud data processing involves a lot of calculations, which affects real-time performance. In addition, traditional mechanical errors and environmental factors may cause data deviations.

[0003] The prior art provides a method and device for storing laser radar point cloud data. This storage method includes: performing coordinate transformation on each laser point in the original laser point cloud data; detecting the laser point after coordinate transformation, and using the change in the laser point coordinate value to determine whether the currently detected laser point is the starting point of a new scan line; when the currently scanned laser point is determined to be the starting point of a new scan line, storing the laser point cloud data on the previous scan line in a buffer and performing an inverse coordinate transformation on each laser point on the previous scan line in the buffer; establishing a spatial index for the scan line to which the inversely transformed laser point belongs and saving it; processing the next scan line, and repeating the above steps until the laser point cloud data on all scan lines has been saved. The device mainly includes a coordinate transformation unit, a detection and judgment unit, a cache unit, and a storage unit.

[0004] However, the existing technology still has the problem of being unable to meet the needs of real-time applications. Therefore, how to invent a three-dimensional laser scanner that can transmit point cloud data in real time and its real-time point cloud scanning method is a technical problem that urgently needs to be solved in this technical field. Summary of the Invention

[0005] In order to solve the problem that existing technologies are difficult to meet real-time application requirements, the present invention provides a three-dimensional laser scanner, a real-time point cloud scanning method and a system, which have the characteristic of being able to reduce the amount of calculation.

[0006] In order to achieve the above-mentioned purpose of the present invention, the technical solutions adopted are as follows:

[0007] A three-dimensional laser scanner includes a main control system, a laser transmitting and receiving module, a drive motor, a code disk, a code disk reading module, and a laser time-of-flight reading module;

[0008] The driving motor is connected to the laser transmitting and receiving module and is used to drive the laser transmitting and receiving module to move in three dimensions;

[0009] The laser emission module is connected to the main control system and is used to receive the laser emission instruction of the main control system and receive the reflected laser and send the laser reflection intensity value to the main control system;

[0010] The code disc is connected to the motor shaft of the drive motor and is used to record the angular position of the drive motor;

[0011] The code disc reading module is connected to the main control system and is used to read the code disc angle parameters and send them to the main control system;

[0012] The laser flight time measurement module is connected to the main control system and is used to measure the laser flight time value.

[0013] A real-time point cloud scanning method based on a three-dimensional laser scanner includes the following specific steps:

[0014] Based on the 3D scanning requirements, the point spacing is set by the main control system, and the speed of the drive motor and the transmission frequency of the laser transmitting and receiving module are set based on the point spacing;

[0015] The main control system controls the drive motor to rotate according to the calculated speed and drives the laser to emit laser according to the laser emission frequency;

[0016] When each laser starts to emit, the main control system collects the angle parameters of the code disk in real time through the code disk reading module and measures the laser flight time value through the laser flight time measurement module; the main control system combines the angle parameters, laser flight time value, and laser reflection intensity value read from the emission signal during the last laser emission into a frame of data and saves it to the raw data buffer;

[0017] The main control system reads the frame data in the raw data buffer in real time and calculates the angle value and distance value to further obtain the three-dimensional coordinates;

[0018] The main control system takes the three-dimensional coordinates and the laser reflection intensity value as a frame of data and stores it in the result buffer.

[0019] Preferably, based on the three-dimensional scanning requirements, the point spacing is set by the main control system and the speed of the drive motor and the transmission frequency of the laser transmitting and receiving module are set based on the point spacing. The specific steps are as follows:

[0020] Measure and calculate the average horizontal and vertical distance R between the scanner and the scan target h and R v , and based on the scanning requirements, preset the horizontal point spacing Δd at a fixed distance n h and longitudinal point spacing Δd v ;

[0021] Assume the laser emission frequency is f, calculate the horizontal axis motor speed ω h :

[0022]

[0023] Similarly, calculate the vertical axis motor speed ω v :

[0024]

[0025] Furthermore, the angle parameters are collected, the laser flight time value is measured, and a frame of data is saved in the raw data buffer. The specific steps are as follows:

[0026] The code disk reading module reads the horizontal axis code disk value and vertical axis code disk value P corresponding to this frame respectively h 、P v ,

[0027] The laser flight time measurement module records the laser flight time value ToF from the laser emission to the reception of the reflected signal after the laser emission of the current frame;

[0028] P h 、P v , ToF form a frame of data and write it into the DDR buffer of the main control system.

[0029] Furthermore, the main control system reads the frame data in the raw data buffer in real time and calculates the angle value and distance value to obtain the three-dimensional coordinates. The specific steps are as follows:

[0030] The main control system reads the frame data of the original data buffer in real time and splits it into the horizontal axis code disk value P h , vertical axis code disk value P v , laser flight time value, laser reflection intensity value;

[0031] Assume that the encoder generates N scales per rotation, and calculate the horizontal axis angle θ′ after subdivision in real time h and the vertical axis angle θ′ v :

[0032]

[0033] Considering the deviation of the code disk value caused by mechanical error and nonlinearity, the horizontal axis angle θ is corrected h and the vertical axis angle θ v :

[0034] θ h =(θ′ h -offset h )×scale h

[0035] θ v =(θ′ v -offset v)×scale v

[0036] offset v ,offset h is the offset obtained by device calibration, scale v ,scale h is the scaling factor obtained through device calibration;

[0037] Taking environmental factors into consideration, the correction factor Cor is calculated to compensate for ToF errors:

[0038] t=Cor*ToF

[0039] Calculate the distance D of the scanned object in real time:

[0040] D=(c*t) / 2

[0041] Where c is the speed of light;

[0042] Use trigonometric functions to convert angles and distances into three-dimensional coordinates (x, y, z):

[0043] x=D*sin(θ h )*cos(θ v )

[0044] y=D*sin(θ v )

[0045] z=D*cos(θ h )*cos(θ v ).

[0046] Furthermore, the offset, scaling factor, and correction factor are specifically:

[0047] Check the actual angles corresponding to several readings on the code disk;

[0048] The 3D laser scanner is used to measure and record the horizontal axis angle E of the horizontal and vertical code disk corresponding to the actual angle. hi and the vertical axis angle E vi , we get the code disk reading set E, which covers the entire rotation range of the code disk;

[0049] Fit linear models using the least squares method and calculate offsets and scaling factors through matrix solving or regression analysis;

[0050] Calculate the atmospheric refractive index N using the Ciddor formula e :

[0051]

[0052] Where P is atmospheric pressure, T is temperature, and e is water vapor pressure;

[0053] Assume the test distance is d known , the theoretical flight time is:

[0054]

[0055] Using this 3D laser scanner in d known The actual measured distance is T measured :

[0056] Calculate the correction factor:

[0057]

[0058] Furthermore, when the three-dimensional coordinates are calculated, dynamic error compensation is also performed. The specific steps are as follows:

[0059] Construct the error model of point cloud data through the covariance propagation law:

[0060] Define the input variables as: the distance d between the scanner and the scan target, the vertical axis angle θ v , horizontal axis angle θ h :

[0061]

[0062] in, is the distance variance, are the horizontal and vertical angle variances, respectively, which are determined by the code disk accuracy. is the covariance;

[0063] Let the coordinate conversion function be f(d,θ v ,θ h )=(X,Y,Z), the Jacobian matrix J is composed of partial derivatives:

[0064]

[0065] Among them, the partial derivative is:

[0066]

[0067] Get the Jacobian matrix:

[0068]

[0069] The covariance matrix of the output variables (X, Y, Z) is: Cov XYZ =J·Cov input ·J T ,

[0070] Using Cov XYZ The trace of is used as an indicator of uncertainty: The weights are defined as: Set threshold d threshold , in d <d threshold Increase the angle weight, when d≥d threshold Add distance weights to dynamically compensate for errors in the calculation process of converting angles and distances into three-dimensional coordinates using trigonometric functions.

[0071] Furthermore, each frame of point cloud data in the result buffer is sent to the cloud in real time, and the receiving end receives the point cloud data including three-dimensional coordinates and laser reflection intensity values ​​in real time through the cloud.

[0072] Furthermore, after uploading to the cloud, a big data model based on machine learning is used to detect the quality of the uploaded data in real time. If it is determined that there is missing data, an alarm will be sent to the 3D scanner for rescanning.

[0073] A real-time point cloud scanning system based on a three-dimensional laser scanner includes a setting module, a control module, an original point cloud frame data combination module, a real-time coordinate conversion module, and a result point cloud frame data combination module;

[0074] The setting module is used to set the point spacing through the main control system based on the three-dimensional scanning requirements and to set the speed of the drive motor and the transmission frequency of the laser transmitting and receiving module based on the point spacing;

[0075] The control module is used by the main control system to control the drive motor to rotate according to the calculated speed and drive the laser to emit laser according to the laser emission frequency;

[0076] The raw point cloud frame data combination module is used for the main control system to collect the angle parameters of the code disk in real time through the code disk reading module and measure the laser flight time value through the laser flight time measurement module when each laser starts to be emitted; the main control system combines the angle parameters, laser flight time value, and laser reflection intensity value read from the emission signal at the last laser emission into a frame of data and saves it in the raw data buffer;

[0077] The real-time coordinate conversion module is used by the main control system to read the frame data of the original data buffer in real time and calculate the angle value and distance value to further obtain the three-dimensional coordinates;

[0078] The result point cloud frame data combination module is used to use the main control system to combine the three-dimensional coordinates and the laser reflection intensity value as a frame of data and store it in the result buffer.

[0079] The beneficial effects of the present invention are as follows:

[0080] The present invention discloses a real-time point cloud scanning method based on a three-dimensional laser scanner. When each laser starts to be emitted, the main control system collects the angle parameters of the code disk in real time through the code disk reading module and measures the laser flight time value through the laser flight time measurement module; reads the data in the original data buffer in real time, calculates its corresponding angle and distance values, and obtains the three-dimensional coordinates. This significantly optimizes the function of the three-dimensional laser scanner, enables it to directly output three-dimensional coordinates, greatly reduces the conversion process of point cloud data, and solves the problem that the existing technology is difficult to meet the needs of real-time applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 It is a signal flow diagram of a three-dimensional laser scanner of the present invention.

[0082] Figure 2 It is a specific flow chart of a real-time point cloud scanning method based on a three-dimensional laser scanner of the present invention. DETAILED DESCRIPTION

[0083] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0084] Example 1

[0085] like Figure 1 As shown, a three-dimensional laser scanner includes a main control system, a laser transmitting and receiving module, a drive motor, a code disk, a code disk reading module, and a laser time-of-flight reading module;

[0086] The driving motor is connected to the laser transmitting and receiving module and is used to drive the laser transmitting and receiving module to move in three dimensions;

[0087] The laser emission module is connected to the main control system and is used to receive the laser emission instruction of the main control system and receive the reflected laser and send the laser reflection intensity value to the main control system;

[0088] The code disc is connected to the motor shaft of the drive motor and is used to record the angular position of the drive motor;

[0089] The code disc reading module is connected to the main control system and is used to read the code disc angle parameters and send them to the main control system;

[0090] The laser time-of-flight measurement module is connected to the main control system to measure the laser flight time. In this embodiment, the main control system uses the Xilinx Zynq UltraScale+ MPSoC series chip, model XCZU2CG-1SFVC784E. The code disk angle compensation algorithm is deployed in the programmable logic unit (PL) on the processor side, and the three-dimensional coordinate conversion algorithm is implemented in parallel using the ARM Cortex-A53 core on the processor side.

[0091] The laser time-of-flight reading module adopts a TDC-GPX chip.

[0092] Example 2

[0093] like Figure 2 As shown, a real-time point cloud scanning method based on a 3D laser scanner includes the following specific steps:

[0094] Based on the 3D scanning requirements, the point spacing is set by the main control system, and the speed of the drive motor and the transmission frequency of the laser transmitting and receiving module are set based on the point spacing;

[0095] The main control system controls the drive motor to rotate according to the calculated speed and drives the laser to emit laser according to the laser emission frequency;

[0096] In this embodiment, specifically, before the step of emitting the pulsed laser, a scanning parameter setting instruction and a scanning start instruction are sent, and the scanning instruction is sent to the main control system. The main control system controls the three-dimensional laser scanner according to the scanning instruction to scan the scene according to the rotation speed and laser transmission frequency calculated according to the setting parameters;

[0097] When each laser starts to emit, the main control system collects the angle parameters of the code disk in real time through the code disk reading module and measures the laser flight time value through the laser flight time measurement module; the main control system combines the angle parameters, laser flight time value, and laser reflection intensity value read from the emission signal during the last laser emission into a frame of data and saves it to the raw data buffer;

[0098] The main control system reads the frame data in the raw data buffer in real time and calculates the angle value and distance value to further obtain the three-dimensional coordinates;

[0099] The three-dimensional coordinate data format is a character string.

[0100] The main control system takes the three-dimensional coordinates and the laser reflection intensity value as a frame of data and stores it in the result buffer.

[0101] In a specific embodiment, based on the three-dimensional scanning requirements, the main control system sets the point spacing and sets the speed of the drive motor and the transmission frequency of the laser transmitting and receiving module based on the point spacing. The specific steps are as follows:

[0102] Measure and calculate the average horizontal and vertical distance R between the scanner and the scan target h and R v , and based on the scanning requirements, preset the horizontal point spacing Δd at a fixed distance n h and longitudinal point spacing Δd v ;

[0103] In this embodiment, based on the requirement of accurate scanning, h and Rv = 10m, preset Δd h =Δd v =0.1m;

[0104] Assume the laser emission frequency is f, calculate the horizontal axis motor speed ω h :

[0105]

[0106] Similarly, calculate the vertical axis motor speed ω v :

[0107]

[0108] In a specific embodiment, the angle parameters are collected, the laser flight time value is measured, and a frame of data is formed and saved in the raw data buffer. The specific steps are as follows:

[0109] The code disk reading module reads the horizontal axis code disk value and vertical axis code disk value P corresponding to this frame respectively h 、P v ,

[0110] The laser flight time measurement module records the laser flight time value ToF from the laser emission to the reception of the reflected signal after the laser emission of the current frame;

[0111] P h 、P v , ToF constitutes a frame of data and is written into the DDR buffer of the main control system through the AXI FULL protocol.

[0112] In a specific embodiment, the main control system reads the frame data of the raw data buffer in real time and calculates the angle value and the distance value, and further obtains the three-dimensional coordinates. The specific steps are as follows:

[0113] The main control system reads the frame data of the original data buffer in real time and splits it into the horizontal axis code disk value P h , vertical axis code disk value P v , laser flight time value, laser reflection intensity value;

[0114] Assume that the encoder generates N scales per rotation, and calculate the horizontal axis angle θ′ after subdivision in real time h and the vertical axis angle θ′ v :

[0115]

[0116] Considering the deviation of the code disk value caused by mechanical error and nonlinearity, the horizontal axis angle θ is corrected h and the vertical axis angle θ v :

[0117] θ h =(θ′ h -offset h )×scale h

[0118] θ v =(θ′ v -offset v )×scale v

[0119] offset v ,offset h is the offset obtained by device calibration, scale v ,scale h is the scaling factor obtained through device calibration;

[0120] Taking environmental factors into consideration, the correction factor Cor is calculated to compensate for ToF errors:

[0121] t=Cor*ToF

[0122] Calculate the distance D of the scanned object in real time:

[0123] D=(c*t) / 2

[0124] Where c is the speed of light;

[0125] Use trigonometric functions to convert angles and distances into three-dimensional coordinates (x, y, z):

[0126] x=D*sin(θ h )*cos(θ v )

[0127] y=D*sin(θ v )

[0128] z=D*cos(θ h )*cos(θ v ).

[0129] In a specific embodiment, the offset, scaling factor, and correction factor are specifically:

[0130] Check the actual angles corresponding to several readings on the code disk;

[0131] The 3D laser scanner is used to measure and record the horizontal axis angle E of the horizontal and vertical code disk corresponding to the actual angle. hi and the vertical axis angle E vi , we get the code disk reading set E, which covers the entire rotation range of the code disk;

[0132] Fit linear models using the least squares method and calculate offsets and scaling factors through matrix solving or regression analysis;

[0133] Calculate the atmospheric refractive index N using the Ciddor formula e :

[0134]

[0135] Where P is atmospheric pressure, T is temperature, and e is water vapor pressure;

[0136] Assume the test distance is d known , the theoretical flight time is:

[0137]

[0138] Using this 3D laser scanner in d known The actual measured flight time is t measured :

[0139] Calculate the correction factor:

[0140]

[0141] In a specific embodiment, when the three-dimensional coordinates are calculated, dynamic error compensation is also performed, and the specific steps are as follows:

[0142] Construct the error model of point cloud data through the covariance propagation law:

[0143] Define the input variables as: the distance d between the scanner and the scan target, the vertical axis angle θ v , horizontal axis angle θ h :

[0144]

[0145] in, is the distance variance, are the horizontal and vertical angle variances, respectively, which are determined by the code disk accuracy. is the covariance;

[0146] Let the coordinate conversion function be f(d,θ v ,θ h )=(X,Y,Z), the Jacobian matrix J is composed of partial derivatives:

[0147]

[0148] Among them, the partial derivative is:

[0149]

[0150] Get the Jacobian matrix:

[0151]

[0152] The covariance matrix of the output variables (X, Y, Z) is: Cov XYZ =J·Cov input ·J T ,

[0153] Using Cov XYZ The trace of is used as an indicator of uncertainty: The weights are defined as: Set threshold d threshold , in d <d threshold Increase the angle weight, when d≥d threshold Add distance weights to dynamically compensate for errors in the calculation process of converting angles and distances into three-dimensional coordinates using trigonometric functions.

[0154] In this embodiment, an octree structure is used to organize the point cloud data of each frame in the result buffer, which facilitates density analysis and area division.

[0155] In a specific embodiment, each frame of point cloud data in the result buffer is also sent to the cloud in real time, and the receiving end receives the point cloud data including three-dimensional coordinates and laser reflection intensity values ​​in real time through the cloud.

[0156] In a specific embodiment, after uploading to the cloud, a big data model based on machine learning is used to detect the quality of the uploaded data in real time. If it is determined that there is data missing, an alarm is issued to the 3D scanner to rescan.

[0157] In this embodiment, the cloud uses the pre-trained machine learning model PointNet++ and the autoencoder PointAE to detect missing areas through reconstruction errors. A high error indicates that there may be a missing area. When a missing area is detected, an alarm signal is sent to the scanner to instruct it to rescan. The scanner rescans according to the original parameters, uploads new data and repeats the detection.

[0158] The present invention thus achieves real-time detection to ensure the quality of point cloud data, reduces subsequent processing errors, automatically rescans to improve the degree of system automation, combines machine learning and rule detection, and balances accuracy and real-time performance.

[0159] Example 3

[0160] A real-time point cloud scanning system based on a three-dimensional laser scanner includes a setting module, a control module, an original point cloud frame data combination module, a real-time coordinate conversion module, and a result point cloud frame data combination module;

[0161] The setting module is used to set the point spacing through the main control system based on the three-dimensional scanning requirements and to set the speed of the drive motor and the transmission frequency of the laser transmitting and receiving module based on the point spacing;

[0162] The control module is used by the main control system to control the drive motor to rotate according to the calculated speed and drive the laser to emit laser according to the laser emission frequency;

[0163] The raw point cloud frame data combination module is used for the main control system to collect the angle parameters of the code disk in real time through the code disk reading module and measure the laser flight time value through the laser flight time measurement module when each laser starts to be emitted; the main control system combines the angle parameters, laser flight time value, and laser reflection intensity value read from the emission signal at the last laser emission into a frame of data and saves it in the raw data buffer;

[0164] The real-time coordinate conversion module is used by the main control system to read the frame data of the original data buffer in real time and calculate the angle value and distance value to further obtain the three-dimensional coordinates;

[0165] The result point cloud frame data combination module is used to use the main control system to combine the three-dimensional coordinates and the laser reflection intensity value as a frame of data and store it in the result buffer.

[0166] Obviously, the above embodiments of the present invention are merely examples for the purpose of illustrating the present invention, and are not intended to limit the embodiments of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A three-dimensional laser scanner, characterized in that: Including main control system, laser transmitting and receiving module, drive motor, code disk, code disk reading module, laser time of flight reading module; The driving motor is connected to the laser transmitting and receiving module and is used to drive the laser transmitting and receiving module to move in three dimensions; The laser emission module is connected to the main control system and is used to receive the laser emission instruction of the main control system and receive the reflected laser and send the laser reflection intensity value to the main control system; The code disc is connected to the motor shaft of the drive motor and is used to record the angular position of the drive motor; The code disc reading module is connected to the main control system and is used to read the code disc angle parameters and send them to the main control system; The laser flight time measurement module is connected to the main control system and is used to measure the laser flight time value.

2. A real-time point cloud scanning method based on a 3D laser scanner, characterized by: The specific steps include: Based on the 3D scanning requirements, the point spacing is set by the main control system, and the speed of the drive motor and the transmission frequency of the laser transmitting and receiving module are set based on the point spacing; The main control system controls the drive motor to rotate according to the calculated speed and drives the laser to emit laser according to the laser emission frequency; When each laser starts to emit, the main control system collects the angle parameters of the code disk in real time through the code disk reading module and measures the laser flight time value through the laser flight time measurement module; the main control system combines the angle parameters, laser flight time value, and laser reflection intensity value read from the emission signal during the last laser emission into a frame of data and saves it to the raw data buffer; The main control system reads the frame data in the raw data buffer in real time and calculates the angle value and distance value to further obtain the three-dimensional coordinates; The main control system takes the three-dimensional coordinates and the laser reflection intensity value as a frame of data and stores it in the result buffer.

3. The real-time point cloud scanning method according to claim 2, characterized in that: Based on the 3D scanning requirements, the point spacing is set by the main control system, and the speed of the drive motor and the transmission frequency of the laser transmitting and receiving module are set based on the point spacing. The specific steps are as follows: Measure and calculate the average horizontal and vertical distance R between the scanner and the scan target h and R v , and based on the scanning requirements, preset the horizontal point spacing Δd at a fixed distance n h and longitudinal point spacing Δd v ; Assume the laser emission frequency is f, calculate the horizontal axis motor speed ω h : Similarly, calculate the vertical axis motor speed ω v :

4. The real-time point cloud scanning method according to claim 3, characterized in that: Collect its angle parameters, measure the laser flight time value, and form a frame of data and save it to the raw data buffer. The specific steps are as follows: The code disk reading module reads the horizontal axis code disk value and vertical axis code disk value P corresponding to this frame respectively h 、P v , The laser flight time measurement module records the laser flight time value ToF from the laser emission to the reception of the reflected signal after the laser emission of the current frame; P h 、P b , ToF form a frame of data and write it into the DDR buffer of the main control system.

5. The real-time point cloud scanning method according to claim 4, characterized in that: The main control system reads the frame data in the raw data buffer in real time and calculates the angle value and distance value to obtain the three-dimensional coordinates. The specific steps are as follows: The main control system reads the frame data of the original data buffer in real time and splits it into the horizontal axis code disk value P h , vertical axis code disk value P v , laser flight time value, laser reflection intensity value; Assume that the encoder generates N scales per rotation, and calculate the horizontal axis angle θ′ after subdivision in real time h and the vertical axis angle θ′ v : Considering the deviation of the code disk value caused by mechanical error and nonlinearity, the horizontal axis angle θ is corrected h and the vertical axis angle θ v : θ h =(θ′ h -offset h )×scale h θ v =(θ′ v -offset v )×scale v offset v ,offset h is the offset obtained by device calibration, scale v ,scale h is the scaling factor obtained through device calibration; Taking environmental factors into consideration, the correction factor Cor is calculated to compensate for ToF errors: t=Cor*ToF Calculate the distance D of the scanned object in real time: D=(c*t) / 2 Where c is the speed of light; Use trigonometric functions to convert angles and distances into three-dimensional coordinates (x, y, z): x=D*sin(θ h )*cos(θ v ) y=D*sin(θ v ) z=D*cos(θ h )*cos(θ v )。 6. The real-time point cloud scanning method according to claim 5, characterized in that: The offset, scaling factor, and correction factor are specifically: Check the actual angles corresponding to several readings on the code disk; The 3D laser scanner is used to measure and record the horizontal axis angle E of the horizontal and vertical code disk corresponding to the actual angle. hi and the vertical axis angle E vi , we get the code disk reading set E, which covers the entire rotation range of the code disk; Fit linear models using the least squares method and calculate offsets and scaling factors through matrix solving or regression analysis; Calculate the atmospheric refractive index N using the Ciddor formula e : Where P is atmospheric pressure, T is temperature, and e is water vapor pressure; Assume the test distance is d known , the theoretical flight time is: Using this 3D laser scanner in d known The actual measured flight time is t measured : Calculate the correction factor:

7. The real-time point cloud scanning method according to claim 6, characterized in that: When the three-dimensional coordinates are calculated, dynamic error compensation is also performed. The specific steps are as follows: Construct the error model of point cloud data through the covariance propagation law: Define the input variables as: the distance d between the scanner and the scan target, the vertical axis angle θ v , horizontal axis angle θ h : in, is the distance variance, are the horizontal and vertical angle variances, respectively, which are determined by the code disk accuracy. is the covariance; Let the coordinate conversion function be f(d,θ v ,θ h )=(X,Y,Z), the Jacobian matrix J is composed of partial derivatives: Among them, the partial derivative is: Get the Jacobian matrix: The covariance matrix of the output variables (X, Y, Z) is: Cov XYZ =J·Cov input ·J T , Using Cov XYZ The trace of is used as an indicator of uncertainty: The weights are defined as: Set threshold d threshold , in d <d threshold Increase the angle weight, when d≥d threshold Add distance weights to dynamically compensate for errors in the calculation process of converting angles and distances into three-dimensional coordinates using trigonometric functions.

8. The real-time point cloud scanning method according to claim 2, characterized in that: Each frame of point cloud data in the result buffer is also sent to the cloud in real time, and the receiving end receives the point cloud data including three-dimensional coordinates and laser reflection intensity values ​​in real time through the cloud.

9. The real-time point cloud scanning method according to claim 8, characterized in that: After uploading to the cloud, a big data model based on machine learning is used to detect the quality of the uploaded data in real time. If it is determined that there is missing data, an alarm will be sent to the 3D scanner for rescanning.

10. A real-time point cloud scanning system based on a three-dimensional laser scanner, characterized by: It includes setting module, control module, original point cloud frame data combination module, real-time coordinate conversion module, and result point cloud frame data combination module; The setting module is used to set the point spacing through the main control system based on the three-dimensional scanning requirements and to set the speed of the drive motor and the transmission frequency of the laser transmitting and receiving module based on the point spacing; The control module is used by the main control system to control the drive motor to rotate according to the calculated speed and drive the laser to emit laser according to the laser emission frequency; The raw point cloud frame data combination module is used for the main control system to collect the angle parameters of the code disk in real time through the code disk reading module and measure the laser flight time value through the laser flight time measurement module when each laser starts to be emitted; the main control system combines the angle parameters, laser flight time value, and laser reflection intensity value read from the emission signal at the last laser emission into a frame of data and saves it in the raw data buffer; The real-time coordinate conversion module is used by the main control system to read the frame data of the original data buffer in real time and calculate the angle value and distance value to further obtain the three-dimensional coordinates; The result point cloud frame data combination module is used to use the main control system to combine the three-dimensional coordinates and the laser reflection intensity value as a frame of data and store it in the result buffer.

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