System and method suitable for underwater structure defect size measurement

Abstract

The invention discloses a system and a method suitable for measuring the defect size of an underwater structure. Simple multifunctional measurement of plane and depth sizes of common defects such as damage, cracks, slab staggering and undermining of the underwater structure is realized by utilizing an unmanned underwater carrier as well as a shooting device, a distance measuring device and a lighting device which are arranged on the unmanned underwater carrier. The method for measuring the plane size of the underwater structure defect comprises the following steps: determining a reference surface and a space rectangular coordinate system; sighting the target; determining the space coordinates of the measuring points, and measuring the plane size of the underwater structure defect by combining the images acquired by the shooting device. The method for measuring the depth dimension of the underwater structure defect comprises the following steps: determining a reference surface and a space rectangular coordinate system; sighting the target; determining space coordinates of measurement points; calculating a target surface equation; and calculating the depth dimension of the underwater structure defect. The method solves the problem of lack of underwater structure defect size measurement means.

Description

Technical Field

[0001] The present invention relates to the field of dimension measurement, and in particular to a system and method suitable for measuring the dimensions of underwater structural defects. Background Art

[0002] As of 2018, there are more than 98,000 reservoirs in my country. Among them, there are nearly 800 large reservoirs, more than 4,100 medium-sized reservoirs, and nearly 94,000 small reservoirs. More than 87% of the dams of these reservoirs were built in the 1950s to 1970s. Due to the economic conditions and technical level at that time, the overall construction standards were low. The average age of my country's reservoirs is nearly 50 years. After decades of operation, most reservoirs have exceeded or are close to their designed service life, and problems such as structural aging, performance degradation and siltation are becoming increasingly serious.

[0003] During the operation period, the underwater structures of hydraulic structures, such as the dam body, dam heel, dam toe, underwater energy dissipation structure, guide walls on both sides, etc., are under the effects of underwater immersion, washing and erosion all year round. It is inevitable that they will be damaged, cracked, misaligned, hollowed out, etc. If the safety of the underwater structures is not checked regularly, it will threaten the safe operation of the hydropower station.

[0004] The inspection of the underwater part of hydraulic structures has always been a weak link in hydropower stations. The operating status of the underwater part of hydraulic structures is a blind spot and pain point in the safe production of hydropower plants. At present, most hydropower stations still use divers to dive, and divers carry underwater cameras equipped with lighting, use their hands or tools to explore and approach the observation area, and conduct video observation after visual confirmation. The diver's diving time is very limited each time, and they cannot carry other inspection equipment except underwater cameras. When working in deep water, divers need to dive with helium and oxygen saturation, and a surface support system is required. The requirements for electricity, oxygen, helium, water and site are high, and the risk of diving operations is very high. Therefore, this traditional underwater inspection operation technology generally has problems such as high cost, low efficiency, difficulty in comprehensive coverage, limited operating depth, and high safety risks, making it difficult to achieve comprehensive dynamic monitoring of underwater safety risks of hydraulic structures. Summary of the invention

[0005] The purpose of the present invention is to provide a system and method suitable for underwater structural defect size measurement, which can realize simple and multifunctional measurement of underwater structural defects.

[0006] The technical solutions provided by this application are as follows:

[0007] In a first aspect, the present application provides a system and method for underwater structural defect size measurement, including an unmanned underwater carrier and a shooting device, a distance measuring device and a lighting device installed on the unmanned underwater carrier; the shooting device and the distance measuring device are installed on the same plane and face the same direction;

[0008] The unmanned underwater carrier is used to carry the shooting device, the distance measuring device and the lighting device to move freely in the water;

[0009] The photographing device is used to collect images of underwater structural defects underwater;

[0010] The distance measuring device comprises a plurality of rangefinders; each rangefinder is used to measure the distance between the rangefinder itself and a measuring point of the rangefinder underwater, and emit visible light to indicate the position of the measuring point;

[0011] The lighting device is used to provide lighting for shooting in a dark underwater environment;

[0012] The spatial coordinates of the measuring point are determined based on the relative position of the rangefinder and the center point of the shooting device and the distance measured by the rangefinder, and the size of the underwater structural defect is measured in combination with the image collected by the shooting device.

[0013] Furthermore, the unmanned underwater carrier may be, but is not limited to: an underwater submersible, an underwater robot.

[0014] Furthermore, the photographing device may be, but is not limited to, a visible light camera.

[0015] The images collected are preferably high-definition digital images.

[0016] Furthermore, the distance measuring device includes four distance measuring devices; the distance measuring devices may be, but are not limited to, laser distance measuring devices. The four laser distance measuring devices are arranged around the photographing device and are arranged symmetrically around the center of the photographing device. The relative positions of the laser distance measuring devices and the photographing device are known.

[0017] In a second aspect, the present application provides a method suitable for measuring underwater structural defects, which measures the size of underwater structural defects based on the above-mentioned system.

[0018] Further, measuring the size of underwater structural defects includes: measuring the plane size of underwater structural defects; the types of underwater structural defects include damage and cracks;

[0019] The measuring of the plane dimensions of underwater structural defects comprises:

[0020] A spatial rectangular coordinate system is established by taking the mounting plane of the camera and the distance measuring device as the reference plane, the reference plane as the XY plane, the center point of the camera as the origin, the center line of the camera perpendicular to the XY plane as the Z axis, and the shooting direction as the positive direction of the Z axis;

[0021] The unmanned underwater carrier is operated so that the underwater structural defect is located in the middle of the field of view of the camera, the measuring point of the rangefinder is on the structural surface around the underwater structural defect, and the structural surface is determined as the target surface;

[0022] The spatial coordinates of the measuring point are determined based on the relative position of the rangefinder and the center point of the shooting device and the distance measured by the rangefinder, and a scale grid is drawn on the target surface in the shooting device based on this. Based on the scale grid, the plane size of the underwater structural defect is roughly measured within the field of view of the shooting device; the spatial coordinates of the measuring point are determined based on the relative position of the rangefinder and the center point of the shooting device and the distance measured by the rangefinder, and then the plane size of the underwater structural defect is accurately measured on the high-definition image of the target surface shot by the shooting device.

[0023] Further, the measuring of the size of underwater structural defects includes: measuring the depth of underwater structural defects; the types of underwater structural defects include damage, misalignment and hollowing;

[0024] The measuring of the depth size of underwater structural defects comprises:

[0025] A spatial rectangular coordinate system is established by taking the mounting plane of the camera and the distance measuring device as the reference plane, the reference plane as the XY plane, the center point of the camera as the origin, the center line of the camera perpendicular to the XY plane as the Z axis, and the shooting direction as the positive direction of the Z axis;

[0026] The unmanned underwater carrier is operated so that the underwater structural defect is in the middle of the field of view of the shooting device; for damage, the measuring points of a part of the rangefinders are on the structural surface around the underwater structural damage defect, and the structural surface is determined as the target surface, and the measuring points of the other part of the rangefinders are at the deepest part of the underwater structural damage defect; for misalignment or hollowing, the measuring points of a part of the rangefinders are on the structural surface on one side of the underwater structural misalignment or hollowing defect, and the structural surface is determined as the target surface, and the measuring points of the other part of the rangefinders are on the other side of the underwater structural misalignment or hollowing defect;

[0027] Determine the spatial coordinates of the measuring point based on the relative position of the rangefinder and the center point of the camera device and the distance measured by the rangefinder;

[0028] Calculate the target surface equation according to the spatial coordinates of the measurement points on the target surface;

[0029] According to the target surface equation and the spatial coordinates of the measuring point of another rangefinder, the distance between the measuring point of the other rangefinder and the target surface, that is, the deepest size of the underwater structure damage defect, the misalignment or hollowing height difference of the underwater structure misalignment or hollowing defect is calculated.

[0030] Furthermore, the distance measuring device includes 4 distance measuring devices; one part of the distance measuring devices includes 3 distance measuring devices, and the other part of the distance measuring devices includes 1 distance measuring device.

[0031] Beneficial effects:

[0032] The present application utilizes an unmanned underwater carrier and a shooting device, a ranging device, and a lighting device installed on the unmanned underwater carrier to realize the plane and depth dimension measurement of common surface defects such as underwater structure damage, cracks, misalignment, and hollowing. The system is simple and can realize multiple measurement functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention can be further understood from the following description in conjunction with the accompanying drawings, in which objects are not necessarily drawn to scale, emphasis instead being placed on illustrating the principles of the embodiments.

[0034] Figure 1 This is a schematic diagram of a method for measuring the plane dimensions of underwater structure damage defects according to an embodiment of the present application;

[0035] Figure 2 This is a schematic diagram of a method for measuring the plane dimensions of a crack defect in an underwater structure according to an embodiment of the present application;

[0036] Figure 3 This is a schematic diagram of a method for measuring the depth size of underwater structure damage defects according to an embodiment of the present application;

[0037] Figure 4 This is a schematic diagram of a method for measuring the depth dimension of a misalignment defect of an underwater structure according to an embodiment of the present application;

[0038] Figure 5 This is a schematic diagram of a method for measuring the depth size of hollowing defects in underwater structures according to an embodiment of the present application.

[0039] In the figure, 1-unmanned underwater carrier; 2-shooting device; 3-rangefinder; 4-illumination device; 5-target surface; 6-irradiation line of the ranging device; 7-measuring point; 8-size grid; 9-damage defect of underwater structure; 10-crack defect of underwater structure; 11-dislocation defect of underwater structure; 12-hollowing defect of underwater structure. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with its embodiments. It should be understood that the specific implementation methods described herein are only used to explain the present invention and do not limit the protection scope of the present invention.

[0041] Embodiment 1:

[0042] See also Figure 1-5 , an embodiment of the present application provides a system suitable for underwater structural defect size measurement, including an unmanned underwater carrier and a shooting device, a distance measuring device and a lighting device installed on the unmanned underwater carrier;

[0043] The unmanned underwater carrier 1 is a carrier that can move freely in water, and can be, but not limited to, an underwater submersible or an underwater robot; the shooting device 2 can collect high-definition digital images of underwater structural defects underwater, and can be, but not limited to, a visible light camera; the rangefinder 3 includes a plurality of rangefinders; each rangefinder is used to measure the distance between itself and a measuring point underwater, and can emit visible light (irradiation line) to indicate the position of the measuring point (irradiation point), and can be, but not limited to, a laser rangefinder. In some embodiments, the rangefinder includes four rangefinders 3, which are arranged around the shooting device and are arranged symmetrically around the center of the shooting device. The relative position of each rangefinder 3 and the shooting device 2 is known, and the side length is b; the lighting device 4 is used to provide lighting in a dark underwater environment.

[0044] Embodiment 2:

[0045] The embodiment of the present application provides a method suitable for measuring the size of underwater structural defects, and the size of underwater structural defects is measured based on the system described in the first embodiment.

[0046] Embodiment three:

[0047] In this embodiment, based on the second embodiment, the underwater structural defect size measurement is the measurement of the underwater structural defect plane size; the underwater structural defect types include damage and cracks. Figure 1-2 .

[0048] In some embodiments, the system may be assembled first, including: installing a camera 2, a rangefinder 3, and a lighting device 4 on the unmanned underwater carrier 1, ensuring that the camera 2 and the rangefinder 3 are strictly facing the same direction and are installed on the same plane.

[0049] The method comprises:

[0050] Take the mounting plane of the photographing device and the distance measuring device as the reference plane, the reference plane as the XY plane, the center point of the photographing device 2 as the origin, the center line of the photographing device 2 perpendicular to the XY plane as the Z axis, and the shooting direction as the positive direction of the Z axis to establish a spatial rectangular coordinate system, then the spatial coordinate of the center point of the photographing device 2 is O(0,0,0), and the spatial coordinates of the center points of the distance measuring devices 3 are A(-b / 2,b / 2,0), B(-b / 2,-b / 2,0), C(b / 2,-b / 2,0), and D(b / 2,b / 2,0);

[0051] The unmanned underwater carrier 1 is operated so that the underwater structural damage 9 or crack 10 defect is located in the middle of the field of view of the camera 2, the measuring point 7 is located on the structural surface around the underwater structural damage 9 or crack 10 defect, and the structural surface is determined as the target surface 5;

[0052] The spatial coordinates of the measuring point 7 are determined based on the relative position of the distance meter 3 and the center point of the camera 2 and the measured distance. Assume that the distances measured by the distance meters 3 are L AA′ , L BB′ , L CC′ , L DD′ The spatial coordinates of each measuring point are A′(-b / 2, b / 2, L AA′ )、B′(-b / 2,-b / 2,L BB′ )、C′(b / 2,-b / 2,L CC′ )、D′(b / 2,b / 2,L DD′ );

[0053] In some embodiments, a scale grid 8 on the target surface can be drawn in the camera 2 according to the spatial coordinates of each measurement point; and based on the scale grid 8, the plane size of the underwater structure damage 9 or crack 10 defect can be roughly measured within the field of view of the camera 2;

[0054] In other embodiments, the planar dimensions of underwater structural damage 9 and / or crack 10 defects can be accurately measured based on the spatial coordinates of each measuring point and the high-definition image of the target surface captured by the camera.

[0055] Embodiment 4:

[0056] In this embodiment, based on the second embodiment, the underwater structural defect size measurement is the underwater structural defect depth measurement; the underwater structural defect types include damage, misalignment and hollowing. Figure 3-5 .

[0057] In some embodiments, the system may be assembled first, including: installing a camera 2, a rangefinder 3, and a lighting device 4 on the unmanned underwater carrier 1, ensuring that the camera 2 and the rangefinder 3 are strictly facing the same direction and are installed on the same plane.

[0058] The method comprises:

[0059] Take the mounting plane of the camera and the distance measuring device as the reference plane, the reference plane as the XY plane, the center point of the camera 2 as the origin, the center line of the camera 2 perpendicular to the XY plane as the Z axis, and the shooting direction as the positive direction of the Z axis to establish a spatial rectangular coordinate system. The spatial coordinate of the center point of the camera 2 is O(0,0,0), and the spatial coordinates of the center points of the distance measuring devices are A(-b / 2,b / 2,0), B(-b / 2,-b / 2,0), C(b / 2,-b / 2,0), and D(b / 2,b / 2,0).

[0060] The unmanned underwater carrier 1 is operated so that the underwater structure damage 9, misalignment 11, and hollowing 12 defects are located in the middle of the field of view of the shooting device 2. For the damage 9, three measuring points are on the structural surface around the underwater structure damage 9 defect, and the structural surface is determined as the target surface 5, and the fourth measuring point is at the deepest part of the underwater structure damage 9 defect; for the misalignment 11 or hollowing 12, three measuring points are on the structural surface on one side of the underwater structure misalignment 11 or hollowing 12 defect, and the structural surface is determined as the target surface 5, and the fourth measuring point is on the other side of the underwater structure misalignment 11 or hollowing 12 defect;

[0061] The spatial coordinates of the measuring point are determined according to the relative position of the distance meter 3 and the center point of the photographing device 2 and the measured distance. Assume that the distances measured by the distance meters 3 are L AA′ , L BB′ , L CC′ , L DD′ The spatial coordinates of each measuring point are A′(-b / 2, b / 2, L AA′ )、B′(-b / 2,-b / 2,L BB′ )、C′(b / 2,-b / 2,L CC′ )、D′(b / 2,b / 2,L DD′ );

[0062] According to the spatial coordinates of the three measuring points on the target surface 5, the target surface equation is calculated. Assuming that the measuring points A′, B′, and C′ are located on the target surface 5, and the measuring point D′ is located at the deepest part of the broken 9 defect or on the other side of the misaligned 11 or hollowed 12 defect, the target surface equation is:

[0063]

[0064] According to the target surface equation and the spatial coordinates of the fourth measuring point, the distance between the fourth measuring point and the target surface 5, that is, the deepest size of the underwater structure damage 9 defect and the dislocation or hollowing height difference of the underwater structure dislocation 11 or hollowing 12 defect are calculated.

[0065] The specific calculation process is as follows:

[0066] First simplify the target surface equation into the following form:

[0067] αx+βy+γz+δ=0

[0068] Among them, α, β, γ, and δ are the target surface equation parameters.

[0069] The distance calculation formula from any point in space to the target surface is as follows:

[0070]

[0071] Substituting the spatial coordinates of the measuring point D′ into the measured point D′, the distance between the measuring point D′ and the target surface 5 can be obtained, that is, the deepest dimension of the underwater structure damage 9 defect, and the height difference of the underwater structure misalignment 11 or hollowing 12 defect:

[0072]

[0073] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A system suitable for underwater structural defect measurement, characterized in that: It comprises an unmanned underwater carrier and a shooting device, a distance measuring device and a lighting device installed on the unmanned underwater carrier; the shooting device and the distance measuring device are installed on the same plane and face the same direction; The unmanned underwater carrier is used to carry the shooting device, the distance measuring device and the lighting device to move freely in the water; The photographing device is used to collect images of underwater structural defects underwater; The distance measuring device comprises a plurality of rangefinders; each rangefinder is used to measure the distance between the rangefinder itself and a measuring point of the rangefinder underwater, and emit visible light to indicate the position of the measuring point; The lighting device is used to provide lighting for shooting in a dark underwater environment; The spatial coordinates of the measuring point are determined based on the relative position of the rangefinder and the center point of the shooting device and the distance measured by the rangefinder, and the size of the underwater structural defect is measured in combination with the image collected by the shooting device.

2. The method according to claim 1, characterized in that The unmanned underwater carrier is an underwater vehicle or an underwater robot.

3. The method according to claim 1, characterized in that The shooting device adopts a visible light camera.

4. The method according to claim 1, characterized in that The distance measuring device comprises four distance measuring devices; the distance measuring devices adopt laser distance measuring devices; the four laser distance measuring devices are arranged around the shooting device and are arranged symmetrically around the center of the shooting device.

5. A method for measuring underwater structural defects, characterized in that: The size of underwater structural defects is measured based on the system described in any one of claims 1 to 4.

6. The method according to claim 5, characterized in that The measuring of the size of underwater structural defects includes: measuring the plane size of underwater structural defects; the types of underwater structural defects include damage and cracks; The measuring of the plane dimensions of underwater structural defects comprises: A spatial rectangular coordinate system is established by taking the mounting plane of the camera and the distance measuring device as the reference plane, the reference plane as the XY plane, the center point of the camera as the origin, the center line of the camera perpendicular to the XY plane as the Z axis, and the shooting direction as the positive direction of the Z axis; The unmanned underwater carrier is operated so that the underwater structural defect is located in the middle of the field of view of the camera, the measuring point of the rangefinder is on the structural surface around the underwater structural defect, and the structural surface is determined as the target surface; The spatial coordinates of the measuring point are determined based on the relative position of the rangefinder and the center point of the shooting device and the distance measured by the rangefinder, and a scale grid on the target surface is drawn in the shooting device. Based on the scale grid, the plane size of the underwater structural defect is roughly measured within the field of view of the shooting device; or, the spatial coordinates of the measuring point are determined based on the relative position of the rangefinder and the center point of the shooting device and the distance measured by the rangefinder, and then the plane size of the underwater structural defect is accurately measured on the high-definition image of the target surface shot by the shooting device.

7. The method according to claim 5, characterized in that The measuring of the size of underwater structural defects includes: measuring the depth of underwater structural defects; the types of underwater structural defects include damage, misalignment and hollowing; The measuring of the depth size of underwater structural defects comprises: A spatial rectangular coordinate system is established by taking the mounting plane of the camera and the distance measuring device as the reference plane, the reference plane as the XY plane, the center point of the camera as the origin, the center line of the camera perpendicular to the XY plane as the Z axis, and the shooting direction as the positive direction of the Z axis; The unmanned underwater carrier is operated so that the underwater structural defect is in the middle of the field of view of the shooting device; for damage, the measuring points of a part of the rangefinders are on the structural surface around the underwater structural damage defect, and the structural surface is determined as the target surface, and the measuring points of the other part of the rangefinders are at the deepest part of the underwater structural damage defect; for misalignment or hollowing, the measuring points of a part of the rangefinders are on the structural surface on one side of the underwater structural misalignment or hollowing defect, and the structural surface is determined as the target surface, and the measuring points of the other part of the rangefinders are on the other side of the underwater structural misalignment or hollowing defect; Determine the spatial coordinates of the measuring point based on the relative position of the rangefinder and the center point of the camera device and the distance measured by the rangefinder; Calculate the target surface equation according to the spatial coordinates of the measurement points on the target surface; According to the target surface equation and the spatial coordinates of the measuring point of another rangefinder, the distance between the measuring point of the other rangefinder and the target surface, that is, the deepest size of the underwater structure damage defect, the misalignment or hollowing height difference of the underwater structure misalignment or hollowing defect is calculated.

8. The method according to claim 7, characterized in that The distance measuring device includes four distance measuring devices; one part of the distance measuring devices includes three distance measuring devices, and the other part of the distance measuring devices includes one distance measuring device.

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