A cavity detection system and method for deep concave areas based on real-time collaboration of multiple sensors

Abstract

The present invention discloses a cavity detection system and method for deep concave areas based on real-time collaboration of multiple sensors. The detection system includes a bracket, a pulley block, a traction rope, a host computer, multiple connecting rods, a measuring device, and a power supply system. Multiple connecting rods are connected in sequence to form a connecting rod group. The connecting rods are hollow. The head end of the connecting rod group is fixed to a pulley block supported by the bracket. The pulley block is controlled by a traction rope. The end of the connecting rod group is connected to a measuring device. A host computer and a power supply system are provided on the ground. The power supply system supplies power to the host computer and the measuring device in the cavity. The host computer of the detection system can obtain information from multiple sensors in the measuring device and can control the measuring device. The detection system of the present invention can effectively obtain high-precision characteristic parameters such as the internal structure, size, burial depth, shape, direction, and boundary of the cavity, solving the problems of the current deep concave cavity detection being easily affected by limited drilling radius and space restrictions, difficulty in measuring characteristic parameters of the cavity, single information output, and single function.

Description

Technical Field

[0001] The present invention belongs to the technical field of void area detection, and in particular relates to a system and method for detecting voids in deep concave areas based on real-time collaboration of multiple sensors. Background Art

[0002] Traditional mineral resource development has primarily relied on underground mining, employing open-pit methods such as room-and-pillar, full-scale, or leave-the-mine methods. This, coupled with scattered mining and predatory, predatory mining of rich ores prior to mining consolidation, inevitably resulted in the formation of numerous underground goafs. With the continuous advancement of technology and the large-scale integrated development of the mining industry, the safe and efficient utilization of limited mineral resources has become an inevitable trend. Consequently, a large number of mines have adopted the underground-to-open-pit mining model, which offers larger scale, higher efficiency, lower costs, and greater resource recovery.

[0003] While this open-pit mining method achieves significant economic benefits, it also faces safety threats from goaf areas left over from previous underground mining operations. Under continuous mining disturbance, the safe thickness of the roof in numerous unidentified goaf areas continues to decrease. These areas can eventually collapse due to vibrations from mining blasting or vehicle transportation, forming deep, large pits. These can cause equipment damage at best, and even loss of life and property at worst. Hidden goaf hazards have become one of the most significant hazards to open-pit mine safety.

[0004] Existing technologies mostly rely on seismic exploration, ground-penetrating radar, and drilling. Seismic exploration and ground-penetrating radar require significant human and material resources and have drawbacks such as complex construction, low exploration accuracy, limited functionality, and an inability to effectively characterize the entire void. Drilling, on the other hand, suffers from limited drilling radius and spatial constraints, making it difficult to accurately measure characteristic parameters such as the size, depth, shape, orientation, and boundaries of concealed voids.

[0005] Therefore, conducting precise detection and research on unknown goafs under open-pit mines, identifying the size, internal structure, and development status of the goafs and conducting safety assessments, and then rationally planning the progress of open-pit mining and conducting safety treatment of goafs, is a technical problem in production safety that urgently needs to be solved in deep open-pit mining. Summary of the Invention

[0006] In response to the shortcomings of the existing technology, the present invention provides a deep-concave area cavity detection system and method based on real-time collaboration of multiple sensors, which solves the problems of deep-concave cavity detection being susceptible to limited drilling radius and space restrictions, difficulty in measuring characteristic parameters of the cavity, single information output, and single function.

[0007] The present invention is achieved through the following technical solutions:

[0008] A cavity detection system for deep concave areas based on real-time collaboration of multiple sensors, comprising a bracket, a pulley block, a traction rope, a host computer, a connecting rod, a measuring device, and a power supply system;

[0009] There are more than one connecting rod, each of which is a hollow structure, and more than one connecting rod is sequentially connected to form a connecting rod group; the head end of the connecting rod group is fixed to a pulley group supported by a bracket, and the pulley group is controlled by a traction rope, and the end of the connecting rod group is connected to a measuring device; a host computer and a power supply system are provided on the ground, and the power supply system supplies power to the host computer on the ground and the measuring device in the airspace;

[0010] The measuring device includes a microcontroller, a first stepper motor, a second stepper motor, an image sensor, a laser ranging sensor, a temperature and humidity sensor, a three-axis acceleration sensor, a long-distance infrared night vision module, an SD card, and an Ethernet module;

[0011] The SD card stores the information obtained by the measuring device, and the stored information includes the distance information L measured by the laser ranging sensor, the three-axis acceleration A measured by the three-axis acceleration sensor, and the three-axis acceleration A measured by the three-axis acceleration sensor. x 、A y 、A z , the rotation angle information of the first stepper motor and the second stepper motor, and the temperature and humidity information of the air area measured by the temperature and humidity sensor;

[0012] The Ethernet module transmits the information obtained by the measuring device, and the transmitted information includes the distance information L measured by the laser ranging sensor, the three-axis acceleration A measured by the three-axis acceleration sensor, and the three-axis acceleration A measured by the three-axis acceleration sensor. x 、A y 、A z , image information of the image sensor, rotation angle information of the first stepper motor and the second stepper motor, and temperature and humidity information of the empty area measured by the temperature and humidity sensor;

[0013] The host computer can obtain the information of each sensor in the measuring device and control the measuring device; the information obtained includes the self-test information of the measuring device, image information, distance information, three-axis acceleration A x 、A y 、A z , the rotation angle information of the first stepper motor and the second stepper motor, the temperature and humidity information of the empty area; the control functions include controlling the self-test of the measuring device, power on and off, the rotation angle of the first stepper motor and the second stepper motor, and the opening and closing of the laser ranging module, camera module and night vision module.

[0014] Preferably, the openings on both sides of the first stepper motor are fixedly connected to the connecting rod by bolts, and the first stepper motor and the second stepper motor are connected to the support frame by a coupling; the rotating shaft of the first stepper motor is connected to the central circular hole of the coupling, the opening on the coupling is connected to the bottom of the support frame by bolts, and the top of the support frame is fixedly connected to the second stepper motor, and the rotating shaft of the second stepper motor is provided with an image sensor, a laser ranging sensor, a three-axis acceleration sensor and a long-distance infrared night vision module.

[0015] Preferably, the image sensor and the laser ranging sensor are located on the same side, and the long-distance infrared night vision module is mounted on the image sensor.

[0016] Preferably, the image sensor is an autofocus wide-angle camera with an object distance range of 2cm to 100m; the night vision distance of the long-distance infrared night vision module is ≤100m; the laser ranging sensor is a TTL output high-precision laser ranging sensor with a measurement accuracy of 1mm and a measurement distance of 0 to 150m; the three-axis acceleration sensor is an angle measurement sensor LIS2DH12.

[0017] The real-time and accurate detection method based on the above detection system includes the following steps:

[0018] Step 1) When the detection system is working, the measuring device is fixed on the connecting rod, and several connecting rods are connected in sequence. The power supply line and the network cable are connected to the measuring device through the hollow inside of the connecting rod. The measuring device is powered on and self-checked. After the self-check is completed, the measuring device begins to transmit images, distance, and temperature and humidity information in real time via Ethernet. The construction personnel can set the diving distance based on the image and distance information transmitted by the host computer, thereby determining the number of connecting rods to be used. When the connecting rod group dives to the appropriate distance, the position of the connecting rod group is fixed;

[0019] Step 2) When the measuring device is operating, the first stepper motor rotates 360° around the center of the end of the connecting rod group as the center of the circle, and the second stepper motor is placed on a bracket connected to the first stepper motor and rotates 180° up and down. The first stepper motor runs 360° at a speed of 0.1° / s. After the operation is completed, the second stepper motor rotates 0.1°, and then the first stepper motor returns to the origin and continues to run 360° at a speed of 0.1° / s. This reciprocating process can detect the distance and image information in the entire empty area.

[0020] Step 3) When the measuring device is working, the measuring device transmits the measurement information to the host computer in real time via Ethernet and stores the measurement information in real time on the SD card. If any fault occurs, the host computer controls the angles of the first stepper motor and the second stepper motor using image information, measuring device angle information, and laser ranging information, so that the system can recover from the fault until the measurement of the measured area is completed;

[0021] Step 4) After the measuring device is completed, the connecting rod is pulled out using the pulley set, the measuring device is disassembled, the SD card is taken out, and the three-dimensional coordinates of the empty area are calculated. The three-axis acceleration sensor directly digitally outputs the acceleration data A of the X, Y, and Z axes. x 、A y 、A z The host computer calculates the roll angle α and pitch angle β through the three-axis acceleration data. The laser measurement distance information corresponding to the angle is L, so the three-dimensional coordinate (X L ,Y L ,Z L ) is (Lcosβcosα, Lcosβsinα, Lsinβ);

[0022] Step 5) The three-dimensional coordinates (X L ,Y L ,Z L ), the upper computer can be used to calculate the outline of the target empty area and construct a virtual entity of the empty area.

[0023] Preferably, in step 4), the roll angle α and pitch angle β are obtained by using the acceleration data A x 、A y 、A z Calculated using the following formula:

[0024]

[0025]

[0026] The beneficial effects of the present invention are as follows:

[0027] (1) The present invention uses both laser ranging sensors and image sensors, which can effectively obtain high-precision characteristic parameters such as the internal structure, size, burial depth, shape, direction and boundary of the void.

[0028] (2) The present invention can obtain real-time images and distance information, and can determine the detection position according to the size of the empty area, thereby facilitating the transmission of more accurate measurement signals.

[0029] (3) The present invention adopts a multi-link connection method, which can adaptively adjust the number of links used according to the size of different voids and is applicable to voids of various sizes, burial depths, and shapes.

[0030] (4) The present invention can realize information acquisition and control functions by combining different measurement requirements and sending instructions to the measuring device. It can also control the detection device under different working conditions. Even if a fault occurs inside the empty area, it can be controlled and reset by the host computer.

[0031] (5) The present invention is equipped with a long-distance night vision infrared fill light, which can acquire high-precision real-time image information under dark conditions in empty areas.

[0032] (6) The present invention supports multifunctional measurement and can measure various parameters such as temperature and humidity, distance, image, and rotation angle of the measuring instrument.

[0033] (7) The present invention adopts a 100Mbps Ethernet module to meet the transmission requirements of high data bandwidth such as images, videos, distance, temperature and humidity.

[0034] (8) The present invention supports multiple communication modes and data output modes, which can transmit effective information in real time and store all data in the SD card, and has high compatibility, flexibility and security. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the principle of a cavity detection system in deep concave areas based on real-time collaboration of multiple sensors;

[0036] Figure 2 is a schematic diagram of the structure of the measuring device;

[0037] Figure 1 、 2 Middle: 1. Bracket; 2. Pulley block; 3. Traction rope; 4. Host computer; 5. Connecting rod; 6. Measuring device; 7. Power supply system; 8. First stepper motor; 8-1. Rotating shaft of first stepper motor; 9. Second stepper motor; 9-1. Rotating shaft of second stepper motor; 10. Coupling; 11. Support frame;

[0038] Figure 3 This is the overall system structure diagram of the measuring device;

[0039] Figure 4 A system program flow chart for the measuring device;

[0040] Figure 5 The stepper motor rotation workflow diagram for the measuring device;

[0041] Figure 6 This is the working flow diagram of the laser ranging sensor of the measuring device;

[0042] Figure 7 The image sensor working flow diagram of the measuring device;

[0043] Figure 8 The workflow diagram for data transmission of Ethernet module of measuring device;

[0044] Figure 9 Workflow diagram for SD card data storage of measurement devices. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] A cavity detection system for deep concave areas based on real-time collaboration of multiple sensors, such as Figure 1 As shown, it includes a bracket 1, a pulley block 2, a traction rope 3, a host computer 4, a connecting rod 5, a measuring device 6 and a power supply system 7.

[0047] like Figure 1 As shown, the number of the connecting rods 5 is more than one, and the connecting rods 5 are hollow structures. More than one connecting rods 5 are connected in sequence to form a connecting rod group; the head end of the connecting rod group is fixed on a pulley group 2 supported by a bracket 1, and the pulley group 2 is controlled by a traction rope 3, and the end of the connecting rod group is connected to a measuring device 6; a host computer 4 and a power supply system 7 are provided on the ground, and the power supply system 7 supplies power to the host computer 4 on the ground and the measuring device 6 in the air area.

[0048] like Figure 3 As shown, the measuring device 6 includes an STM32 microcontroller, a first stepper motor 8, a second stepper motor 9, an image sensor, a laser ranging sensor, a temperature and humidity sensor, a three-axis acceleration sensor, a long-distance infrared night vision module, an SD card, and an Ethernet module.

[0049] like Figure 2 As shown, the openings on both sides of the first stepper motor 8 are bolted to the connecting rod 5. The first stepper motor 8 and the second stepper motor 9 are connected via a coupling 10 and a support frame 11. The first stepper motor's rotating shaft 8-1 is connected to the central circular hole of the coupling 10. The upper opening of the coupling 10 is bolted to the bottom of the support frame 11. The top of the support frame 11 is fixedly connected to the second stepper motor 9. The second stepper motor's rotating shaft 9-1 is equipped with an image sensor, a laser ranging sensor, a three-axis accelerometer, and a long-range infrared night vision module. The axis lines of the first stepper motor's rotating shaft 8-1 and the second stepper motor's rotating shaft 9-1 are arranged at a 90° angle to each other. During operation, the coupling 10 rotates with the first stepper motor's rotating shaft 8-1, driving the second stepper motor 9 connected to it. The rotation of the second stepper motor's rotating shaft 9-1 also drives the image sensor, laser ranging sensor, three-axis accelerometer, and long-range infrared night vision module installed thereon.

[0050] The SD card stores the information obtained by the measuring device 6, including the distance information L measured by the laser ranging sensor, the three-axis acceleration A measured by the three-axis acceleration sensor, and the three-axis acceleration A measured by the three-axis acceleration sensor. x 、A y 、A z, the rotation angle information of the first stepper motor and the second stepper motor, and the temperature and humidity information of the air area measured by the temperature and humidity sensor.

[0051] The Ethernet module transmits the information obtained by the measuring device 6, and the transmitted information includes the distance information L measured by the laser ranging sensor, the three-axis acceleration A measured by the three-axis acceleration sensor, and the three-axis acceleration A measured by the three-axis acceleration sensor. x 、A y 、A z , image information of the image sensor, rotation angle information of the first stepper motor and the second stepper motor, and temperature and humidity information of the empty area measured by the temperature and humidity sensor.

[0052] The host computer 4 can obtain the information of each sensor in the measuring device 6 and can control the measuring device 6; the information obtained includes the self-test information of the measuring device 6, image information, distance information, three-axis acceleration A x 、A y 、A z , the rotation angle information of the first stepper motor and the second stepper motor, the temperature and humidity information of the empty area; the control functions include controlling the self-test of the measuring device 6, power on and off, the rotation angle of the first stepper motor and the second stepper motor, and the opening and closing of the laser ranging module, the camera module and the night vision module.

[0053] The image sensor and the laser ranging sensor are located on the same side. While transmitting real-time images, they measure empty areas of several meters to tens of meters. Since the underground empty areas are dark, the long-distance infrared night vision module is installed on the image sensor to provide infrared fill light for the camera.

[0054] The image sensor is an auto-focus wide-angle camera with an object distance range of 2 cm to 100 m. The focal length, image transmission frame rate and image resolution of the camera can be set by the host computer 4 to obtain a clear image of the empty area.

[0055] The night vision distance of the long-range infrared night vision module can reach 100m.

[0056] The laser distance measuring sensor is a TTL output type high-precision laser distance measuring sensor with a measurement accuracy of 1 mm and a measurement distance of 0 to 150 m.

[0057] The three-axis acceleration sensor is an angle measurement sensor LIS2DH12, which has ultra-low power consumption and high precision.

[0058] The specific steps of the real-time and accurate detection method based on the above detection system are as follows:

[0059] (1) Figure 1As shown, when the detection system is working, the measuring device 6 is fixed on the connecting rod 5, the connecting rod 5 is 5m long, and several connecting rods 5 are connected in sequence. The power supply line and the network cable are connected to the measuring device 6 through the hollow inside of the connecting rod 5. The measuring device 6 is turned on for self-test. After the self-test is completed, the measuring device 6 starts to transmit images, distances, and temperature and humidity information in real time through Ethernet. The construction personnel can set the diving distance through the image and distance information transmitted by the host computer 4, thereby judging the number of connecting rods 5 to be used. When the connecting rod group dives to the appropriate distance, the position of the connecting rod group is fixed.

[0060] (2) Figure 4 As shown, when the measuring device 6 is working, it adopts the μCOS-II operating system. In order to realize all functions, five processes are created, namely the stepper motor rotation process, the laser ranging thread, the video image acquisition thread, the Ethernet data transmission process and the data storage process.

[0061] like Figure 1 、 Figure 5 As shown, when the stepper motor of the measuring device 6 starts to rotate, the rotation flag is first detected in real time. The rotation flag indicates whether rotation is required at this time. The flag is controlled by the host computer 4 and the current operating state. When in the automatic operating state, the flag is automatically set by the program; when the rotation is controlled by the host computer 4, it can be set according to actual needs and the configuration instructions of the host computer 4. When the stepper motor is automatically running, the first stepper motor rotates 360° with the center of the end of the connecting rod group as the center of the circle, and the second stepper motor is placed on the bracket connected to the first stepper motor and rotates 180° up and down; the first stepper motor runs 360° at a speed of 0.1° / s. After the operation is completed, the second stepper motor rotates 0.1°, and then the first stepper motor returns to the origin and continues to run 360° at a speed of 0.1° / s. This reciprocating process can detect the distance and image information in the entire empty area.

[0062] (3) Figure 6 As shown, the laser sensor has two working modes, which can be single-trigger or continuous measurement. Since the vibration caused by the rotation of the motor and the surface structural defects or other complex structures of the empty area during the operation of the measuring device 6 lead to the delay of continuous measurement, this system adopts a single-trigger mode and multiple measurements. Ten sampling points are obtained within the 0.1° rotation range in the three-dimensional space, and the average is taken as the three-dimensional coordinate value of the point. When the laser ranging sensor starts working, the three-axis acceleration sensor outputs the three-axis acceleration information A in real time. x 、A y 、A z ,In order to facilitate data processing, the system sends valid ,data to the message queue of the operating system, and uses ,the message queue to cache and forward the data.

[0063] like Figure 7As shown in the figure, after the camera captures the image, it uses Ethernet to transmit the image information. Because the image acquisition speed does not match the Ethernet data transmission speed, directly sending the data will result in data loss. To avoid this, this system has designed a DMA buffer for data cache. Memory is allocated to this buffer, allowing images and data to be cached in a timely manner and image data to be retrieved at any time.

[0064] like Figure 8 As shown, this system uses 100Mbps Ethernet for all data transmission. The system obtains data from the message queue of the operating system. The transmitted data includes the distance information L measured by the laser ranging sensor and the three-axis acceleration A measured by the three-axis acceleration sensor. x 、A y 、A z , camera image information, rotation angle information of the first and second stepper motors, and air area temperature and humidity information.

[0065] like Figure 9 As shown, the SD card of the measuring device 6 stores the information obtained by the measuring device 6. The system uses RTC to obtain time information as the file name to facilitate the organization of data files. The system obtains data from the message queue of the operating system for storage. The stored information includes the distance information L measured by the laser ranging sensor, the three-axis acceleration A measured by the three-axis acceleration sensor, and the distance L measured by the three-axis acceleration sensor. x 、A y 、A z , the rotation angle information of the first and second stepper motors, and the temperature and humidity information of the empty area.

[0066] If any fault occurs, the host computer 4 controls the angles of the first and second stepper motors through image information, angle information of the measuring device 6 and laser ranging information, so that the system can recover from the fault until the measurement work of the measurement area is completed.

[0067] (4) After the measuring device 6 is completed, the pulley group 2 is used to pull out the connecting rod group, the measuring device 6 is disassembled, the SD card is taken out, and the three-dimensional coordinates of the empty area are calculated. The three-axis acceleration sensor directly digitally outputs the acceleration data A of the X, Y, and Z axes. x 、A y 、A z The host computer 4 calculates the roll angle α and pitch angle β by combining the three-axis acceleration data with the following formula:

[0068]

[0069]

[0070] The laser measurement distance information corresponding to the roll angle α and pitch angle β is L, then the three-dimensional coordinate (X L,Y L ,Z L ) is (Lcosβcosα,Lcosβsinα,Lsinβ).

[0071] (5) According to the three-dimensional coordinates (X L ,Y L ,Z L ), the host computer 4 can then calculate the target void contour and construct a virtual entity of the void, quantifying, visualizing, and digitizing the void representation. It can also provide advance warning of voids in areas outside the boundaries of the comprehensive detection mining platform. This provides reliable quantitative data and a theoretical basis for risk assessment, safety management, and optimized mining design for mining platforms containing voids.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A cavity detection system for deep concave areas based on real-time collaboration of multiple sensors, characterized by: It includes a bracket, a pulley block, a traction rope, a host computer, a connecting rod, a measuring device and a power supply system; There are more than one connecting rod, each of which is a hollow structure, and more than one connecting rod is sequentially connected to form a connecting rod group; the head end of the connecting rod group is fixed to a pulley group supported by a bracket, and the pulley group is controlled by a traction rope, and the end of the connecting rod group is connected to a measuring device; a host computer and a power supply system are provided on the ground, and the power supply system supplies power to the host computer on the ground and the measuring device in the airspace; The measuring device includes a microcontroller, a first stepper motor, a second stepper motor, an image sensor, a laser ranging sensor, a temperature and humidity sensor, a three-axis acceleration sensor, a long-distance infrared night vision module, an SD card, and an Ethernet module; The SD card stores the information obtained by the measuring device, and the stored information includes the distance information L measured by the laser ranging sensor, the three-axis acceleration A measured by the three-axis acceleration sensor, and the three-axis acceleration A measured by the three-axis acceleration sensor. x 、A y 、A z , the rotation angle information of the first stepper motor and the second stepper motor, and the temperature and humidity information of the air area measured by the temperature and humidity sensor; The Ethernet module transmits the information obtained by the measuring device, and the transmitted information includes the distance information L measured by the laser ranging sensor, the three-axis acceleration A measured by the three-axis acceleration sensor, and the three-axis acceleration A measured by the three-axis acceleration sensor. x 、A y 、A z , image information of the image sensor, rotation angle information of the first stepper motor and the second stepper motor, and temperature and humidity information of the empty area measured by the temperature and humidity sensor; The host computer can obtain the information of each sensor in the measuring device and control the measuring device; the information obtained includes the self-test information of the measuring device, image information, distance information, three-axis acceleration A x 、A y 、A z , the rotation angle information of the first stepper motor and the second stepper motor, the temperature and humidity information of the empty area; the control functions include controlling the self-test of the measuring device, power on and off, the rotation angle of the first stepper motor and the second stepper motor, and the opening and closing of the laser ranging module, camera module and night vision module.

2. The cavity detection system for deep concave areas based on real-time collaboration of multiple sensors according to claim 1 is characterized in that: The openings on both sides of the first stepper motor are fixedly connected to the connecting rod by bolts, and the first stepper motor and the second stepper motor are connected to the support frame by a coupling; the rotating shaft of the first stepper motor is connected to the central circular hole of the coupling, and the opening on the coupling is connected to the bottom of the support frame by bolts, and the top of the support frame is fixedly connected to the second stepper motor, and the rotating shaft of the second stepper motor is provided with an image sensor, a laser ranging sensor, a three-axis acceleration sensor and a long-distance infrared night vision module.

3. The cavity detection system for deep concave areas based on real-time collaboration of multiple sensors according to claim 1 is characterized in that: The image sensor and the laser ranging sensor are located on the same side, and the long-distance infrared night vision module is installed on the image sensor.

4. The cavity detection system for deep concave areas based on real-time collaboration of multiple sensors according to claim 3 is characterized in that: The image sensor is an autofocus wide-angle camera with an object distance range of 2cm to 100m; the night vision distance of the long-range infrared night vision module is ≤100m; the laser ranging sensor is a TTL output high-precision laser ranging sensor with a measurement accuracy of 1mm and a measurement distance of 0 to 150m; the three-axis acceleration sensor is an angle measurement sensor LIS2DH12.

5. A real-time and accurate detection method based on the detection system according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1) When the detection system is working, the measuring device is fixed on the connecting rod, and several connecting rods are connected in sequence. The power supply line and the network cable are connected to the measuring device through the hollow inside of the connecting rod. The measuring device is powered on and self-checked. After the self-check is completed, the measuring device begins to transmit images, distance, and temperature and humidity information in real time via Ethernet. The construction personnel can set the diving distance based on the image and distance information transmitted by the host computer, thereby determining the number of connecting rods to be used. When the connecting rod group dives to the appropriate distance, the position of the connecting rod group is fixed; Step 2) When the measuring device is operating, the first stepper motor rotates 360° around the center of the end of the connecting rod group as the center of the circle, and the second stepper motor is placed on a bracket connected to the first stepper motor and rotates 180° up and down. The first stepper motor runs 360° at a speed of 0.1° / s. After the operation is completed, the second stepper motor rotates 0.1°, and then the first stepper motor returns to the origin and continues to run 360° at a speed of 0.1° / s. This reciprocating process can detect the distance and image information in the entire empty area. Step 3) When the measuring device is working, the measuring device transmits the measurement information to the host computer in real time via Ethernet and stores the measurement information in real time on the SD card. If any fault occurs, the host computer controls the angles of the first stepper motor and the second stepper motor using image information, measuring device angle information, and laser ranging information, so that the system can recover from the fault until the measurement of the measured area is completed; Step 4) After the measuring device is completed, the connecting rod is pulled out using the pulley set, the measuring device is disassembled, the SD card is taken out, and the three-dimensional coordinates of the empty area are calculated. The three-axis acceleration sensor directly digitally outputs the acceleration data A of the X, Y, and Z axes. x 、A y 、A z The host computer calculates the roll angle α and pitch angle β through the three-axis acceleration data. The laser measurement distance information corresponding to the angle is L, so the three-dimensional coordinate (X L ,Y L ,Z L ) is (Lcosβcosα, Lcosβsinα, Lsinβ); Step 5) The three-dimensional coordinates (X L ,Y L ,Z L ), the upper computer can be used to calculate the outline of the target empty area and construct a virtual entity of the empty area.

6. The real-time accurate detection method according to claim 5, characterized in that: Step 4) The roll angle α and pitch angle β are calculated by the acceleration data A x 、A y 、A z Calculated using the following formula:

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