Portable tunnel face image extraction equipment

Abstract

The utility model relates to the technical field of tunnel face recognition and detection, and discloses a portable tunnel face image extraction device which comprises a binocular camera, a distance measuring element and a compass are installed on the binocular camera, the distance measuring element is installed at the front end of the binocular camera, and the compass is installed at the rear end of the binocular camera. The distance measuring element is arranged at the center position of a center line between two lenses of the binocular camera, the distance measuring element is used for detecting the distance between a shot obstacle in front of the binocular camera and the binocular camera, and the compass is used for indicating the shooting direction of the binocular camera; the portable tunnel face image extraction equipment can conveniently and effectively obtain a tunnel face image under complex working conditions and accurately calibrate the real size of the image, is not limited by shooting positions, reduces potential safety hazards, and is simple in overall structure and portable.

Description

Technical Field

[0001] This utility model relates to the field of tunnel face recognition and detection technology, specifically a portable tunnel face image extraction device. Background Technology

[0002] In the construction of highway and railway tunnels, hydraulic tunnels, and underground mines, image recognition of the tunnel face is a crucial means of assessing construction status and quality. In particular, the measurement and statistical analysis of face cracks based on extracted images form the foundation for rock mass quality evaluation and surrounding rock classification. Currently, in many engineering projects, specialized photographers directly capture panoramic images of the tunnel face to obtain tunnel face images, which are then further processed.

[0003] The detailed features of the tunnel face images captured using this method are unclear, and due to factors such as the shooting angle, the images of different parts are inaccurate, making it difficult to accurately complete subsequent crack identification and measurement statistics. Furthermore, this method struggles to accurately obtain the true dimensions of the images, thus making it difficult to determine the actual size of the cracks at the tunnel face. Current solutions typically involve manually calibrating specific landmarks or objects in the images to estimate the tunnel face dimensions and then calculating the crack length. This method not only increases the workload but can also introduce significant errors during calibration, leading to inaccurate crack parameter measurements and calculations. In addition, the harsh environmental conditions of underground engineering also limit the flexibility of tunnel face photography, severely restricting image acquisition during construction. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a portable tunnel face image extraction device that can conveniently and effectively acquire tunnel face images under complex working conditions and accurately determine the true size of the images.

[0005] The objective of this utility model is achieved through the following technical solution:

[0006] A portable tunnel face image extraction device includes a binocular camera, on which a ranging element and a compass are mounted. The ranging element is mounted at the front end of the binocular camera and is positioned at the center of the center line between the two lenses of the binocular camera. The ranging element is used to detect the distance between the obstacle being photographed in front of the binocular camera and the binocular camera. The compass is used to indicate the shooting direction of the binocular camera.

[0007] Furthermore, it also includes a leveling base, which comprises a base plate and a top plate, the base plate and the top plate being connected by three anchor screws. A level is installed on the top plate, and the binocular camera is mounted on the top plate, with the shooting direction of the binocular camera parallel to the top plate.

[0008] Furthermore, it also includes a rotary base, which is connected to the top plate, and the binocular camera is rotatably connected to the rotary base.

[0009] Furthermore, it also includes a screw jack, the housing of which is fixedly connected to the top plate, the screw of which is perpendicular to the top plate, and the rotary seat is fixedly installed on the top end of the screw of which is the screw jack.

[0010] Furthermore, it also includes a tripod, the tripod head of which is detachably connected to the base plate.

[0011] The beneficial effects of this utility model are:

[0012] This portable tunnel face image extraction device includes a binocular camera equipped with a rangefinder and a compass. When capturing images of the tunnel face, shooting points can be set at any distance in front of the face, and the binocular camera can be moved to these points for shooting. The compass indicates the shooting direction of the binocular camera, allowing adjustment of the shooting direction at each point to maintain consistency. The rangefinder detects the distance between the camera and any obstacles in front of it, acquiring and recording the distance from the tunnel face to the corresponding shooting point during shooting. Therefore, at each shooting point, a horizontal image of that point and the actual distance from that point to the tunnel face can be obtained. By combining the actual distance of each point with the focal length, magnification, and physical parameters of the binocular camera at each point, the images captured at each point can be analyzed and calculated to obtain the actual length and width parameters of the image. Then, the images captured at each shooting point can be scaled according to the actual length and width parameters and directly stitched together to form a complete, realistic, and detailed overall image of the tunnel face.

[0013] This portable tunnel face image extraction device has a simple and portable overall structure. The shooting location is not limited by the harsh environmental conditions of underground engineering. The shooting point can be selected in any flat and safe area to reduce safety hazards. During shooting, distance parameters and detailed images are directly obtained, so that the stitched overall view of the tunnel face is more detailed and the accuracy of crack identification is improved. In addition, during the shooting process, the compass not only marks the shooting direction of each shooting point, but also records the shooting direction, which is the direction of the tunnel axis, providing a basis for subsequent calculation of crack dip angle and inclination. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of a portable tunnel face image extraction device according to the present invention;

[0015] Figure 2for Figure 1 A schematic diagram of the structure shown after removing the tripod;

[0016] Figure 3 This is a schematic diagram illustrating the principle of a portable tunnel face image extraction device during image analysis and calculation according to this utility model.

[0017] In the diagram, 1-Binocular camera, 2-Distance measuring element, 3-Compass, 4-Leveling base, 5-Base plate, 6-Top plate, 7-Foot screw, 8-Level, 9-Tripod, 10-Rotating base, 11-Screw jack. Detailed Implementation

[0018] The technical solution of this utility model is described in further detail below with reference to the accompanying drawings, but the scope of protection of this utility model is not limited to the following description.

[0019] like Figure 1 , Figure 2 As shown, a portable tunnel face image extraction device includes a binocular camera 1, a rangefinder 2 and a compass 3 mounted on the binocular camera 1. The rangefinder 2 is mounted at the front end of the binocular camera 1 and is positioned at the center of the centerline between the two lenses of the binocular camera 1. The rangefinder 2 is used to detect the distance between the obstacle being photographed in front of the binocular camera 1 and the binocular camera 1; the compass 3 is used to indicate the shooting direction of the binocular camera 1.

[0020] When capturing images of the tunnel face, this portable tunnel face image extraction device allows for the selection of multiple shooting points at any distance in a flat and safe area in front of the tunnel face. When shooting at the central shooting point (approximately close to the tunnel axis), the binocular camera 1 is kept horizontal and facing the tunnel face. The horizontal distance from this point to the tunnel face is measured using the ranging element 2, and the shooting direction of the binocular camera is measured using the compass 3 (since it faces the tunnel face, this direction corresponds to the tunnel axis). When moving the binocular camera 1 to other shooting points, it is kept horizontal, and the shooting direction is adjusted according to the compass 3 to maintain consistency each time. The actual horizontal distance from the corresponding shooting point to the tunnel face is measured and recorded using the ranging element 2 during each shooting session. Therefore, at each shooting point, a horizontal image of that point and the actual dimensions of that point to the tunnel face can be obtained. By combining the actual dimensions of each point with the focal length, magnification, and physical parameters of the binocular camera 1 at each point, the images captured at each point can be analyzed and calculated to obtain the true length and width parameters corresponding to the scene in the captured image. Based on the calculated true length and width, scaling processing is performed, and the scaled images can be directly stitched together to form a complete and realistic overall image of the tunnel face.

[0021] This portable tunnel face image extraction device has a simple and portable overall structure. The above-mentioned method can be used to take pictures by hand. The shooting position is not limited by the severe environmental conditions of underground engineering, and the shooting point can be selected arbitrarily to reduce safety hazards. During shooting, distance parameters and detailed images are directly obtained, making the stitched overall picture of the tunnel face more detailed and improving the accuracy of crack identification. In addition, the shooting direction can be measured by a compass 3. This shooting direction is calibrated at the middle shooting point near the tunnel location and is the direction of the tunnel axis, which can provide a basis for subsequent calculation of crack dip angle and inclination.

[0022] In practical implementation, an image processing device is also included, which can be a computer with image processing and stitching tools. The aforementioned ranging element 2 is an infrared ranging sensor, and the compass 3 is an electronic compass. The infrared ranging sensor, electronic compass, and binocular camera 1 are all electrically connected to the image processing device. The infrared ranging sensor can transmit the distance value measured during each shot to the image processing device, the electronic compass can transmit the azimuth value detected during each shot to the image processing device, and the binocular camera 1 can transmit the images captured during each shot, the focal length of the binocular camera 1, and the magnification value to the image processing device. After receiving the data, the computer can directly perform image analysis, calculation, and stitching processing on the image by the image processing device.

[0023] The above analysis and calculation refers to automatically obtaining image attributes and calculating the true size based on the imported image data. The calculation formula is as follows:

[0024] When N≤N0:

[0025] ,

[0026] ,

[0027] When N > N0:

[0028] ,

[0029] ,

[0030] Where D is the actual width of the image frame;

[0031] H—The actual height corresponding to the image frame;

[0032] f—Focal length of the binocular camera 1 during shooting;

[0033] f0—the critical focal length for optical zoom and digital zoom of the binocular camera 1.

[0034] N—Magnification of the image captured by the binocular camera 1 during shooting;

[0035] N0—The critical magnification between optical zoom and digital zoom for the binocular camera 1;

[0036] L—The working distance of the binocular camera 1, i.e., the distance value detected by the range measuring element 2 during shooting;

[0037] B—The baseline of the binocular camera 1, i.e., the center line of the two lenses of the binocular camera 1;

[0038] h—height of the lens sensor of binocular camera 1;

[0039] d—width of the lens sensor of the binocular camera 1.

[0040] The aforementioned stitching process refers to the image processing equipment using an image stitching toolbox to scale the images according to the actual length and width parameters corresponding to the captured images, thereby completing the stitching of the panoramic image of the tunnel face. For example, when stitching images A and B taken from similar shooting points, images A and B, directly captured by the binocular camera 1, have the same size. Assuming the actual width corresponding to the length of image A is 3m and the actual height corresponding to the width of image A is 2m, and the actual width corresponding to the length of image B is 4.5m and the actual height corresponding to the width of image B is 3m, before stitching, image B can be enlarged by 1.5 times based on the actual length or width of image A, and then stitched directly using the overlapping features of the two images as the basis. After stitching, the size of the panoramic image of the tunnel face is automatically calculated based on the actual dimensions of all images before stitching, providing data support for subsequent tunnel face crack identification and 3D reconstruction.

[0041] Furthermore, it also includes a leveling stand 4, whose structure is similar to that of the leveling platform of engineering theodolites, levels, etc. It includes a base plate 5 and a top plate 6, which are connected by three leveling screws 7. A level 8 is installed on the top plate 6. After the base plate 5 is fixed to the bracket, the top plate 6 can be adjusted to a horizontal state using the leveling screws 7. The level 8 can be a bubble level, used to observe the leveling status during leveling. A binocular camera 1 is set on the top plate 6, and the shooting direction of the binocular camera 1 is parallel to the top plate 6. Compared with handheld shooting, the base plate 5 can be mounted on any bracket for support during use. The leveling stand 4 levels the top plate 6, so that the binocular camera 1 can accurately shoot in the horizontal direction, maintaining the consistency of the shooting direction at each shooting point. In specific implementation, it also includes a tripod 9 commonly used in engineering inspection, and the base plate 5 is detachably connected to the tripod head of the tripod 9.

[0042] Furthermore, it also includes a rotating base 10, which is connected to the top plate 6. The binocular camera 1 is rotatably connected to the rotating base 10. By rotating, the shooting direction of the binocular camera 1 can be adjusted. At the aforementioned intermediate shooting point, the binocular camera 1 can be rotated to face the working face for shooting. Alternatively, after placing and leveling the tripod at other shooting points, the binocular camera 1 can be rotated and adjusted according to the compass 3 to ensure that the shooting direction of the binocular camera 1 is consistent at each shooting point. A locking screw is provided on the rotating base 10, which can be used to lock the binocular camera 1 after adjustment.

[0043] Furthermore, it also includes a screw jack 11, which is an existing device. It drives a worm gear to rotate a worm wheel, and the worm wheel and the screw form a screw-nut pair. When the worm wheel rotates, it can drive the screw to rise and fall. The housing of the screw jack 11 is fixedly connected to the top plate 6, and the screw of the screw jack 11 is perpendicular to the top plate 6. The rotary seat 10 is fixedly installed on the top of the screw of the screw jack 11. Rotating the worm gear of the screw jack 11 can adjust the height of the rotary seat 10 and the binocular camera 1, so as to obtain images of the tunnel face at different heights at each shooting point, which can be stitched together to form a complete overall image of the tunnel face.

[0044] The above description is merely a preferred embodiment of this utility model. It should be understood that this utility model is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this utility model should be protected within the scope of the appended claims.

Claims

1. A portable tunnel face image extraction device, characterized in that, The device includes a binocular camera, on which a rangefinder and a compass are mounted. The rangefinder is mounted at the front of the binocular camera and positioned at the center of the center line between the two lenses of the binocular camera. The rangefinder is used to detect the distance between the object being photographed in front of the binocular camera and the camera. The compass is used to indicate the shooting direction of the binocular camera.

2. The portable tunnel face image extraction device according to claim 1, characterized in that, It also includes a leveling base, which includes a base plate and a top plate connected by three anchor bolts. A level is installed on the top plate, and the binocular camera is mounted on the top plate with its shooting direction parallel to the top plate.

3. The portable tunnel face image extraction device according to claim 2, characterized in that, It also includes a rotary base, which is connected to the top plate, and the binocular camera is rotatably connected to the rotary base.

4. The portable tunnel face image extraction device according to claim 3, characterized in that, It also includes a screw jack, the housing of which is fixedly connected to the top plate, the screw of which is perpendicular to the top plate, and the rotary seat is fixedly installed on the top of the screw of which is the screw jack.

5. The portable tunnel face image extraction device according to claim 2, characterized in that, It also includes a tripod, the tripod head of which is detachably connected to the base plate.

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