A three-dimensional deformation auxiliary monitoring device and method for slope stability

Abstract

The present invention discloses a three-dimensional deformation auxiliary monitoring device and method for slope stability, including a laser emission end, a laser reception end, and a power supply system. The power supply system supplies power to the laser emission end and the laser reception end. The laser emission end includes a laser rangefinder, a controller, a collimated laser emitter, a GPRS module, and a first wireless communication module. The laser rangefinder, the GPRS module, and the first wireless communication module are all bidirectionally communicatively connected to the controller. The controller is connected to a cloud server through the GPRS module, and the collimated laser emitter is connected to the output end of the controller. The laser reception end includes an image acquisition device, a processor, a memory, and a second wireless communication module. The image acquisition device is connected to the input end of the processor, and the second wireless communication module and the memory are both connected to the processor through I / O interfaces, providing an automated device for slope deformation monitoring, helping to realize remote monitoring of three-dimensional slope deformation, and meeting the requirements of high precision, real-time performance, all-weather, automation, and networked monitoring.

Description

Technical Field

[0001] The present invention relates to three-dimensional deformation monitoring of slope stability, and particularly to a three-dimensional deformation auxiliary monitoring device and method for slope stability. Background Art

[0002] The transportation infrastructure still maintains a relatively fast development speed, with the total mileage of highways and the mileage of expressways increasing continuously. As one of the main highway construction projects, the scale of slope construction is becoming increasingly large. In China, the geological environment is complex, and the terrain is mainly mountainous and plateau. Special soils such as loess, permafrost, expansive soil, saline soil, and soft soil are widely distributed. To ensure the safety and reliability of the slope prevention engineering system and prevent the adverse effects of slope disasters on the safety of various highways, it is necessary to conduct safety inspections, evaluations, and make reasonable disposal and maintenance measures for slopes.

[0003] Slope stability monitoring is an important means to ensure slope safety and an important part of slope engineering design, construction, and operation. Monitoring the deformation of slopes during construction and operation will provide a scientific basis for various decisions to ensure project safety and basic data for modifying designs and guiding construction. Slope stability monitoring has become an indispensable important means to ensure the construction and operation safety of highway projects. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a three-dimensional deformation auxiliary monitoring device and method for slope stability, providing an automated device for slope monitoring and helping to realize real-time remote monitoring of slope states.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a three-dimensional deformation monitoring device for slope stability, including a laser emission end, a laser reception end, and a power supply system. The power supply system powers the laser emission end and the laser reception end. The laser emission end includes a laser rangefinder, a controller, a collimated laser emitter, a GPRS module, and a first wireless communication module. The laser rangefinder, the GPRS module, and the first wireless communication module are all in bidirectional communication connection with the controller. The controller is connected to a cloud server through the GPRS module. The first wireless communication module is used to send signals to the laser reception end. The collimated laser emitter is connected to the output end of the controller. The laser reception end includes an image acquisition device, a processor, a memory, and a second wireless communication module. The image acquisition device is connected to the input end of the processor. The second wireless communication module and the memory are both connected to the processor through I / O interfaces.

[0006] The controller uses an STM32 single-chip microcomputer controller, and the processor uses an FPGA; the laser rangefinder, GPRS module, and first wireless communication module are all connected to the controller through RS485 communication lines, and the FPGA is connected to the second wireless communication module through an RS485 communication line; in the laser receiving end, the processor is also connected to a VGA interface, the memory uses SDRAM, and the image acquisition device uses a COMS camera.

[0007] The laser receiving end is provided with a transmissive target and a reflective target. The transmissive target is used to receive the laser of the laser displacement measuring instrument. Along the laser transmission direction, the image acquisition device is arranged behind the transmissive target. The transmissive target and the reflective target are arranged at the top of the slope, and the diffused filter flat panel serves as the target surface of the transmissive target.

[0008] The power supply system includes a photovoltaic module and a storage battery. The power output end of the photovoltaic module is connected to a transformer, and the output end of the transformer is connected to the power input ends of the storage battery, laser transmitting end, and laser receiving end. The power output end of the storage battery is connected to the power input ends of the laser transmitting end and the laser receiving end.

[0009] A slope stability monitoring method based on the device of the present invention includes the following steps:

[0010] The laser transmitting end is the main control end. The controller connects to the cloud server through the GPRS module. After establishing the connection, the collimated laser emitter is periodically turned on, and a communication instruction is sent to the laser receiving end through the first wireless communication module;

[0011] The image acquisition device acquires images in real time. The laser receiving end acquires the images collected by the image acquisition device through the processor, calculates the absolute position of the light spot based on the image data, and after receiving the communication instruction from the transmitting end, transmits the absolute position of the light spot back through the second wireless module;

[0012] After the laser transmitting end receives the absolute position data of the light spot, it obtains the distance data between the laser receiving end and the laser transmitting end through the laser rangefinder, and then sends the distance data to the cloud server through the GPRS module. The cloud server saves the distance data to the database and publishes the real-time data and historical data to the web page through the IIS service;

[0013] The three-dimensional displacement amount characterizing the slope stability is calculated through the initial position data after the device is installed and the current absolute position data, and the monitoring of the slope stability is completed.

[0014] After the laser receiving end collects the images, it simultaneously outputs the image data through the VGA interface to observe whether the images are consistent with the actual images in the laboratory, achieving the purpose of quickly debugging the system and checking whether the system is in a normal working state.

[0015] When calculating the absolute position of the light spot based on the said image data, the specific steps are as follows:

[0016] Step 1): Apply the Gaussian pyramid model to the collected target image to obtain the ROI region, where the ROI region is the light spot region of the target image;

[0017] Step 2): Calculate the light spot center using the gray centroid method in the ROI region;

[0018] Step 3): Conduct target camera calibration, and convert the light spot coordinate data into the coordinate position of the target through the image calibration formula.

[0019] The said Step 1) specifically includes the following steps: After Gaussian blurring the target image, perform subsampling operation, and reduce the size to 1 / 4 of the original. Perform the Gaussian pyramid algorithm multiple times to obtain the light spot region of the target image.

[0020] The said Step 2) is specifically as follows: The set of all laser light spot pixel points is Q and the gray value of the pixel point is f(i, j). After the image is processed by the threshold segmentation algorithm, the gray value of the laser light spot pixel point is 255, and the gray value of the background pixel point is 0. Then the calculation formula for the light spot center coordinates (x0, y0) is shown as follows:

[0021] where (i, j) is the coordinate of the laser light spot pixel point in the target image.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] The laser emission end of the device of the present invention includes a laser rangefinder, a controller, a collimated laser emitter, a GPRS module, and a first wireless communication module. The laser rangefinder assists in accurately measuring the distance in real time. The GPRS module provides remote connection. The first wireless communication module and the second wireless communication module enable mutual communication between the laser receiving end and the laser emission end. The laser receiving end includes an image acquisition device, a processor, a memory, and a second wireless communication module; the image acquisition device is connected to the input end of the processor, and both the second wireless communication module and the memory are connected to the processor through I / O interfaces and can continuously and automatically monitor. The generated distance data and image data are transmitted to and stored in a remote server, providing an automated device for three-dimensional deformation monitoring of slopes and helping to realize real-time remote monitoring of three-dimensional deformation of slopes.

[0024] The method of the present invention combines a high-precision laser reference and optoelectronic image processing. It uses a pyramid model to extract the spot area of the target image, calculates the position of the spot center by the gray centroid method, and then converts the spot coordinate data into the coordinate position of the target through the calibration of the camera. The present invention uses a transmissive target to convert the laser beam into spot image information and collects it through a CMOS. For the collected image, the pyramid model is used to extract the spot area, and the gray centroid method is used to quickly detect the position of the spot center in the spot image, so that three-dimensional deformation monitoring of the slope can be carried out. The present invention combines a high-precision laser reference and an intelligent optoelectronic imaging target to realize the measurement of two-dimensional deformation of the target plane for slope stability, and at the same time uses a laser distance sensor to complete the measurement of the distance from the reference point to the target surface, so as to complete a three-dimensional deformation measurement system for slope stability. The monitoring system using this method has a measurement error of less than 0.25 mm, and real-time data can be viewed on the web side, meeting the requirements of high precision, real-time, all-weather, automation, and networked monitoring. Description of the Drawings

[0025] Figure 1 It is a schematic diagram of the principle of three-dimensional displacement monitoring for slope stability.

[0026] Figure 2 It is a translation model diagram of the target system.

[0027] Figure 3 It is a rotation model diagram of the target system.

[0028] Figure 4 It is a block diagram of a three-dimensional displacement monitoring system for slope stability.

[0029] Figure 5 It is a schematic diagram of the image ROI pyramid model.

[0030] Figure 6 It is the sampling principle.

[0031] Figure 7 It is an image size conversion diagram.

[0032] Figure 8 It is a monocular target coordinate system. Detailed Embodiment

[0033] The following will describe the present invention in detail with reference to the drawings and embodiments.

[0034] The present invention combines a high-precision laser reference and optoelectronic image processing, and compensates for the rotation of the target through a three-dimensional inclinometer, and proposes a high-precision, real-time, all-weather, and automated three-dimensional displacement monitoring method for slope stability.

[0035] Reference Figure 1 and Figure 4, A three-dimensional deformation auxiliary monitoring device for slope stability, comprising a laser emission end, a laser reception end and a power supply system. The power supply system supplies power to the laser emission end and the laser reception end. The laser emission end includes a laser rangefinder, a controller, a collimated laser emitter, a GPRS module and a first wireless communication module. The laser rangefinder, the GPRS module and the first wireless communication module are all in bidirectional communication connection with the controller. The controller is connected to a cloud server through the GPRS module. The first wireless communication module is used to send signals to the laser reception end. The collimated laser emitter is connected to the output end of the controller. The laser reception end includes an image acquisition device, a processor, a memory and a second wireless communication module; the image acquisition device is connected to the input end of the processor, and both the second wireless communication module and the memory are connected to the processor through I / O interfaces.

[0036] The controller adopts an STM32 single-chip microcomputer controller, and the processor adopts an FPGA; the laser rangefinder, the GPRS module and the first wireless communication module are all connected to the controller through RS485 communication lines, and the FPGA is connected to the second wireless communication module through an RS485 communication line; in the laser reception end, the processor is also connected to a VGA interface, and the VGA interface is connected to a display unit, and the memory adopts SDRAM.

[0037] The power supply system includes a photovoltaic module and a storage battery. The power output end of the photovoltaic module is connected to a transformer, and the output end of the transformer is connected to the power input ends of the storage battery, the laser emission end and the laser reception end. The power output end of the storage battery is connected to the power input ends of the laser emission end and the laser reception end.

[0038] A transmissive target and a reflective target are provided at the laser reception end. The transmissive target is used to receive the laser of the laser displacement measuring instrument. Along the laser transmission direction, the image acquisition device is arranged behind the transmissive target. The transmissive target and the reflective target are arranged at the top of the slope.

[0039] The diffused filter flat panel serves as the target surface of the transmissive target; the image acquisition device adopts a COMS camera.

[0040] See Figure 1 , The three-dimensional displacement monitoring system for slope stability includes a laser collimated image displacement measuring instrument and a phase distance sensor.

[0041] On the right side is the laser emission end, which emits two beams of laser, respectively used to measure the displacement of the target surface and the displacement perpendicular to the target surface. On the left side is the laser receiving end, which includes a transmissive target and a reflective target. One transmissive target is used to receive the laser of the laser reference image displacement measuring instrument, and image information is collected through a vision sensor behind the target at the laser emission end to calculate the displacement on the surface of the transmissive target. The other reflective target is used to reflect the laser of the phase distance sensor back to the sensor to measure the distance between the emission end and the receiving end. By combining the displacement on the target surface and the displacement perpendicular to the target surface, a three-dimensional displacement monitoring system for slope stability can be obtained.

[0042] See Figure 2 , taking a point in the initial state as the reference point, establish a coordinate system O-xyz, where O is the origin of coordinates, -x is the laser direction, and the yz plane is the target plane. The target is translated to O', and the movement amounts in the x, y, and z directions are ξ, η. When the target system is installed and fixed, the laser collimation image displacement measuring instrument can obtain the η by measuring the displacement amount of the center of the light spot on the transmissive target, and the phase laser rangefinder can obtain ξ by measuring the reduction amount of the distance size.

[0043] The parallel displacements Δ in the x, y, and z directions are denoted as εx, εy, and εz; the target system is translated from the initial state O to O', and the translation amount is (εx, εy, εz); a point P on the object is also translated to P', and the displacement amount is also (εx, εy, εz);

[0044] It can be analyzed that: the coordinates of point P are (x0, y0, z0), and the coordinates of point P' are (x1, y1, z1), satisfying:

[0045]

[0046] Subtracting the coordinates of point P from the coordinates of point P', the displacement amount of the target can be obtained as:

[0047]

[0048] The position of the laser reference is fixed, the coordinates of point P remain unchanged, and the entire target system is translated. Therefore, relative to the laser reference, the displacement amount of point P is (-εx, -εy, -εz), where εx and εy are measured using the optoelectronic image target, and εz is the difference measured by the laser ranging sensor.

[0049] See Figure 3, in addition to translational displacement, the target often rotates during the displacement process. Although the motion law of the entire target system is not yet clear, the motion of the entire system can be divided into: parallel displacements Δ in the x, y, and z directions, denoted as εx, εy, and εz; rotational errors around the three coordinate axes x, y, and z, denoted as θx, θy, and θz. The motion result with errors can be analyzed as: P' rotates (θx, θy, θz) around O' to reach P”, that is, the object moves from P to P” through translation and rotation. The coordinates of P” are (x2, y2, z2), satisfying:

[0050]

[0051] Substituting Equation 3 into Equation 4, we get:

[0052]

[0053] Expanding Equation 5 gives:

[0054]

[0055] The above equation can be regarded as point P rotating (θx, θy, θz) around the coordinate axes x, y, and z, and then moving to obtain P”.

[0056] See Figure 4 , the working process of the system is as follows:

[0057] 1. The laser emission end is the main control end. The STM32 controller uses the GPRS module to connect to the Alibaba Cloud server. After establishing the connection, the collimated laser emitter is turned on regularly, and communication instructions are sent to the receiving end using the first wireless communication module.

[0058] 2. The laser receiving end uses the FPGA processor to obtain the CMOS camera image, uses SDRAM as a buffer, calculates the absolute position of the light spot using the light spot processing method, and transmits the absolute position of the light spot back through the second wireless module after receiving the communication instruction from the emission end.

[0059] 3. After the laser emission end receives the absolute position data of the light spot, it obtains the distance data between the receiving end and the emission end through the laser rangefinder, then packs the data and sends it to the server through the GPRS module. The server saves the data in the database and publishes the real-time data and historical data to the web page through the IIS service. Any client can access the corresponding domain name to view and download the data. 4. The server can calculate the three-dimensional displacement of the slope stability through the initial position data after the device installation and the current absolute position data, and complete the monitoring of the slope stability.

[0060] After the laser receiving end captures the image, it simultaneously outputs the image data through VGA. In the laboratory, observe whether the image is consistent with the actual image to quickly debug the system and check whether the system is in a normal working state. The server can also display and control the data through the service to achieve the monitoring of the three-dimensional displacement of the slope stability.

[0061] The phase-type distance sensor amplitude-modulates the laser beam and measures the phase delay generated by the modulated light projecting onto the target on the slope and then reflecting back and forth. By measuring the phase difference to indirectly measure time, it reduces the difficulty of directly measuring the round-trip time. Therefore, its accuracy can easily reach the millimeter level and even the micron level.

[0062] The laser reference image displacement measuring instrument uses the principle of linear transmission of laser. It takes the laser beam as the measurement reference, and uses the transmissive imaging target to convert the displacement of the slope on the target surface into the displacement of the light spot on the target surface. Then, by using imaging and image processing techniques to calculate the displacement of the light spot center, the displacement value of the slope on the target surface can be obtained.

[0063] See Figure 5 , the image pyramid is mainly used for image size conversion. At the bottom of the pyramid is the high-resolution image, and at the top is the low-resolution image. The Gaussian pyramid is mainly used for downsampling, that is, reducing the size of the image. Assume that the nth layer of the image pyramid is denoted as f n , denotes the scale change factor, then the image f of the n + 1th layer n+1 is shown as the following formula.

[0064] f n+1 = f n φ (1)

[0065] The process of the Gaussian pyramid algorithm for processing images is to perform Gaussian blurring on the nth layer image and then perform subsampling operations. First, perform a Gaussian kernel convolution operation on the image, and then remove the even rows and even columns of the image to obtain the image with reduced resolution of the n + 1th layer. Then the image of the n + 1th layer is only 1 / 4 of the image of the nth layer. Similarly, it can be known that the image of the n + 2th layer is only 1 / 16 of the image of the nth layer. The calculation formula is shown as the following formula.

[0066]

[0067] In the formula, G n+1 (i, j) and G n (2i + m, 2j + n) represent the images of the n + 1th layer and the nth layer respectively, and W(m, n) is the Gaussian convolution kernel.

[0068] See Figure 6, Subsample the image after Gaussian convolution, then remove the even rows and columns to reduce the image size to 1 / 4 of the original. After multiple Gaussian pyramid algorithm processes, more-sized pyramid images can be obtained.

[0069] See Figure 7 , The original image size is 752×480. Reducing the size twice for the original image gives the best effect, that is, the size of the topmost image G2(i,j) is 1 / 16 of the original image G0(i,j).

[0070] See Figure 8 , The target system is a monocular two-dimensional measurement system. The camera is vertically installed on the target working plane, and the position and internal and external parameters of the camera are fixed. Taking the optical axis of the camera as the center and the direction from the camera to the target surface as the square to establish a coordinate system. The origin O of the target coordinate system w is selected as the intersection point of the optical axis center and the target plane, and Z w is in the same direction as Z c . On the working plane, the target coordinates are expressed as (x w , y w , 0), and the coordinates of the target point under the camera can be obtained as:

[0071]

[0072] In the formula: R = I, P = [0, 0, d] T is the external parameter matrix of the camera, and d is the distance from the optical axis center point O c to the target center point O w . For two points P1 = [x w1 , y w1 , 0] and P2 = [x w2 , y w2 , 0] on the working plane, their image coordinate points are respectively, [x c1 , y c1 , z c , [x c2 , y c2 , z c . Substitute into Equation 5 and subtract the two equations to get:

[0073]

[0074]

[0075] By calibrating the two parameters k xd = k x / d, k yd = k y / d, the calibration of the camera can be completed.

[0076] The present invention combines a high-precision laser reference and an intelligent optoelectronic imaging target to achieve the measurement of two-dimensional deformation of the target plane for slope stability. At the same time, a laser ranging sensor is used to complete the distance measurement from the reference point to the target surface, thereby completing a three-dimensional deformation measurement system for slope stability. The monitoring system using this method has a measurement error of less than 0.25 mm, and real-time data can be viewed on the web side, meeting the requirements of high precision, real-time performance, all-weather, automation, and networked monitoring.

Claims

1. A three-dimensional deformation monitoring device for slope stability, characterized in that, It includes a laser emission end, a laser reception end, and a power supply system. The power supply system supplies power to the laser emission end and the laser reception end. The laser emission end includes a laser rangefinder, a controller, a collimated laser emitter, a GPRS module, and a first wireless communication module. The laser rangefinder, the GPRS module, and the first wireless communication module are all in bidirectional communication connection with the controller. The controller is connected to a cloud server through the GPRS module. The first wireless communication module is used to send signals to the laser reception end. The collimated laser emitter is connected to the output end of the controller. The laser reception end includes an image acquisition device, a processor, a memory, and a second wireless communication module; the image acquisition device is connected to the input end of the processor, and both the second wireless communication module and the memory are connected to the processor through I / O interfaces; the controller uses an STM32 single-chip microcomputer controller, and the processor uses an FPGA; the laser rangefinder, the GPRS module, and the first wireless communication module are all connected to the controller through RS485 communication lines, and the FPGA is connected to the second wireless communication module through an RS485 communication line; in the laser reception end, the processor is also connected to a VGA interface, the memory uses SDRAM, and the image acquisition device uses a COMS camera; the laser reception end is provided with a transmissive target and a reflective target. The transmissive target is used to receive the laser of the laser displacement measuring instrument. Along the laser transmission direction, the image acquisition device is arranged behind the transmissive target. The transmissive target and the reflective target are arranged at the top of the slope, and the diffused filter plane plate serves as the target surface of the transmissive target.

2. The three-dimensional deformation monitoring device for slope stability according to claim 1, characterized in that The power supply system includes a photovoltaic module and a storage battery. The power output end of the photovoltaic module is connected to a transformer, and the output end of the transformer is connected to the power input ends of the storage battery, the laser emission end, and the laser reception end. The power output end of the storage battery is connected to the power input ends of the laser emission end and the laser reception end.

3. A slope stability monitoring method based on the device described in claim 1 or 2, characterized in that, It includes the following steps: The laser emission end is the main control end. The controller is connected to the cloud server through the GPRS module. After establishing the connection, the collimated laser emitter is periodically turned on, and a communication instruction is sent to the laser reception end through the first wireless communication module; The image acquisition device acquires images in real time. The laser reception end obtains the images acquired by the image acquisition device through the processor, calculates the absolute position of the light spot according to the image data, and transmits the absolute position of the light spot back through the second wireless module after receiving the communication instruction from the emission end; After the laser emission end receives the absolute position data of the light spot, it obtains the distance data between the laser reception end and the laser emission end through the laser rangefinder, and then sends the distance data to the cloud server through the GPRS module. The cloud server saves the distance data to the database and publishes the real-time data and historical data to the web page through the IIS service; Calculate the three-dimensional displacement amount characterizing the slope stability through the initial position data after the equipment is installed and the current absolute position data to complete the monitoring of the slope stability; when calculating the absolute position of the light spot according to the image data, the specific steps are as follows: Step 1) Use the Gaussian pyramid model for the acquired target image to obtain the ROI region, and the ROI region is the light spot region of the target image; Step 2) Calculate the center of the light spot in the ROI area using the gray centroid method; Step 3) Perform calibration of the target camera, and convert the light spot coordinate data into the coordinate position of the target through the image calibration formula; The specific steps of the said Step 1) include the following steps: After Gaussian blurring the target image, perform subsampling operation, and reduce the size to 1 / 4 of the original. Perform the Gaussian pyramid algorithm multiple times to obtain the light spot area of the target image.

4. The slope stability monitoring method according to claim 3, wherein: After the laser receiving end collects the image, it outputs the image data through the VGA interface at the same time, observes whether the image is consistent with the actual image in the laboratory, achieves the purpose of quickly debugging the system, and checks whether the system is in a normal working state.

5. The slope stability monitoring method according to claim 3, characterized in that, The specific steps of step 2) are as follows: The set of all laser spot pixel points is Q, and the gray value of the pixel points is , after the image is processed by the threshold segmentation algorithm, the gray value of the laser spot pixel points is 255, and the gray value of the background pixel points is 0. Then the light spot center coordinates The calculation formula is shown as follows: , where (i, j ) are the pixel coordinates of the laser spot in the target image.

Images