CN110942516B - Tunnel roaming video generation method based on laser scanning data - Google Patents

Tunnel roaming video generation method based on laser scanning data Download PDF

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CN110942516B
CN110942516B CN201911208329.6A CN201911208329A CN110942516B CN 110942516 B CN110942516 B CN 110942516B CN 201911208329 A CN201911208329 A CN 201911208329A CN 110942516 B CN110942516 B CN 110942516B
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tunnel
point cloud
perspective projection
section
section point
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CN110942516A (en
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徐宏
刘丹
杨永强
李勇
仇峰涛
杜雷
陈和
王凯
王浩
安欢
李崎
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China Railway First Engineering Group Co Ltd
Intelligent Technology Branch of China Railway First Engineering Group Co Ltd
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China Railway First Engineering Group Co Ltd
Intelligent Technology Branch of China Railway First Engineering Group Co Ltd
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    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T17/00Three dimensional [3D] modelling, e.g. data description of 3D objects
    • G06T17/20Finite element generation, e.g. wire-frame surface description, tesselation
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00Image analysis
    • G06T7/60Analysis of geometric attributes
    • G06T7/62Analysis of geometric attributes of area, perimeter, diameter or volume
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00Indexing scheme for image analysis or image enhancement
    • G06T2207/10Image acquisition modality
    • G06T2207/10016Video; Image sequence
    • G06T2207/10021Stereoscopic video; Stereoscopic image sequence
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00Indexing scheme for image analysis or image enhancement
    • G06T2207/10Image acquisition modality
    • G06T2207/10028Range image; Depth image; 3D point clouds

Abstract

The invention discloses a tunnel roaming video generation method based on laser scanning data, which comprises the following steps: 1. collecting laser scanning data of a tunnel wall; 2. carrying out interpolation calibration on the number of scanning lines of the point cloud of the cross section; 3. acquiring the coordinates of a section scanning point and the diameter of the section by taking the center of the section of the tunnel as the center of a circle; 4. acquiring gray information corresponding to the cross-section point cloud; 5. generating an orthographic image of each ring of the tunnel lining segment; 6. generating a frame of perspective projection image; 7. generating frame-by-frame perspective projection images; 8. and generating the roaming video along the mileage direction of the tunnel. The invention utilizes the perspective projection technology to project objects in a visual range to a single plane with the effect of human vision of 'near-large-far-small', generates a frame-by-frame perspective projection image along the direction of the mileage of the tunnel, can generate a roaming video by setting the number of image frames moving per second, vividly displays the space perspective image of the objects, is intuitive, clear, real and high in efficiency, does not need illumination, does not need manual modeling, and has high video definition.

Description

Tunnel roaming video generation method based on laser scanning data
Technical Field
The invention belongs to the technical field of tunnel roaming video generation, and particularly relates to a tunnel roaming video generation method based on laser scanning data.
Background
At present, for monitoring, deformation detection and the like in the fields of large civil engineering and the like, there are modes based on manual detection, based on stereoscopic vision detection, based on laser scanning detection and the like. The manual detection can obtain a high-precision result by means of a high-precision measuring instrument, such as a level gauge, a total station and the like, but has the defects of low efficiency, high labor intensity and the like; based on stereoscopic vision detection, after left and right images of a region to be detected are acquired through a binocular camera, contour, position and depth information of an object to be detected is acquired through threshold segmentation, feature point detection, extraction, stereoscopic matching and the like. The laser scanning technology can obtain a large amount of coordinate point cloud, laser reflectivity and other information on the surface of an object, quickly reconstruct the outline of the object, generate a gray image of the object and the like, has the advantages of high speed, high precision, small influence of weather change, strong robustness and the like, and is gradually applied to the field of large-scale engineering, such as subway tunnel detection and the like. At present, the tunnel is detected based on laser scanning, usually, the point cloud is directly processed and analyzed through an algorithm, but the visualization is poor.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide a tunnel roaming video generation method based on laser scanning data, which utilizes the perspective projection technology to project the objects in the visual range to a single plane with the effect of human eye vision of "near-large-far-small", to generate the frame-by-frame perspective projection images along the mileage direction of the tunnel, and the static sequence image images are displayed rapidly and continuously, so as to form the moving false image.
In order to solve the technical problems, the invention adopts the technical scheme that: a tunnel roaming video generation method based on laser scanning data is characterized by comprising the following steps:
step one, collecting laser scanning data of a tunnel wall: erecting a laser scanner on a movable carrier, setting the moving speed of the movable carrier, presetting the scanning resolution and sampling frequency of the laser scanner, covering the inner wall of a tunnel by using a 2D section spiral scanning mode of the laser scanner, moving and collecting section point clouds with laser reflectivity on the inner wall of the tunnel along the mileage direction of the tunnel, and taking the scanning point coordinate of each section point cloud as the center of a circle by using the center of the laser scanner;
step two, interpolation calibration of scanning line number of the point cloud of the cross section: calculating a theoretical value of the number of section point cloud scanning lines on one ring of fixed length of a tunnel lining segment according to the moving speed of a moving carrier and the sampling frequency of a laser scanner, comparing the theoretical value of the number of the section point cloud scanning lines with the number of actual section point cloud scanning lines of the corresponding tunnel lining segment, and performing interpolation processing on the number of the section point cloud scanning lines with uneven number of the actual section point cloud scanning lines of the tunnel lining segment to obtain each section point cloud scanning line with even distribution along the mileage direction of the tunnel;
step three, acquiring the coordinates of a section scanning point and the diameter of the section by taking the center of the section of the tunnel as the circle center: performing robust estimation on the section point cloud scanning points after the section point cloud scanning line number interpolation calibration, eliminating rough difference points, and obtaining section scanning point coordinates and section diameters by using the center of the tunnel section as the center of a circle through circle center fitting processing;
step four, obtaining gray information corresponding to the cross-section point cloud: acquiring reflection intensity information of the corresponding cross-section point cloud according to the laser reflectivity of each cross-section point cloud, and performing circle center orthographic projection on the reflection intensity of the cross-section point cloud to acquire a gray value of each scanning point in the cross-section point cloud;
fifthly, generating an orthographic image of each ring of the tunnel lining segment: constructing an image gray matrix according to gray information corresponding to each section point cloud scanning line on each ring of tunnel lining segment, and adding a geographic label to generate an orthophotograph of each ring of tunnel lining segment;
step six, generating a frame of perspective projection image: selecting a visual angle, setting a visual field angle FOV and a closest visual distance and a farthest visual distance corresponding to different positions of the tunnel by taking human eyes as the visual angle, taking a projection plane corresponding to the farthest visual distance as a perspective projection plane of the perspective projection, and performing the perspective projection according to a formula
Figure BDA0002297440340000021
To obtain
Figure BDA0002297440340000031
Calculating the coordinate value rho of the ith section point cloud scanning line coordinate in the perspective range of the tunnel on the perspective projection plane i Wherein r is i The point cloud scanning line coordinate of the ith section in the perspective range of the tunnel, wherein l is the fixed distance between a viewing angle point and a perspective projection plane i The distance between the viewing angle point and the section of the ith section point cloud scanning line in the perspective range of the tunnel;
gradually transiting from the nearest visible distance to the farthest visible distance in the perspective range of the tunnel, carrying out perspective projection on each section point cloud scanning line in the perspective range of the tunnel, and corresponding the coordinates and gray scale information of each section point cloud scanning line in the perspective projection plane in the perspective range of the tunnel one by one to generate a frame of perspective projection image;
step seven, the step six is circulated for multiple times, and perspective projection images of frames by frames along the mileage direction of the tunnel are generated until the moving carrier stops moving, and the laser scanner does not collect laser scanning data of the tunnel wall any more;
step eight, generating a roaming video along the direction of the mileage of the tunnel: and setting the number of frames of the perspective projection images output every second, continuously outputting the perspective projection images frame by frame according to the time sequence, and generating a roaming video which is along the direction of the mileage of the tunnel and simulates the visual angle of human eyes.
The tunnel roaming video generation method based on the laser scanning data is characterized in that: in the first step, the laser scanner is a three-dimensional laser scanner Faro or a Z + F9012 three-dimensional laser scanner.
The tunnel roaming video generation method based on the laser scanning data is characterized by comprising the following steps: and fifthly, the geographic label comprises a tunnel lining segment ring number, mileage, deformation, a disease range and facility equipment.
The tunnel roaming video generation method based on the laser scanning data is characterized in that: the moving speed of the moving carrier in the first step is 3 km/h-10 km/h; the scanning resolution of the laser scanner is 3-5; the sampling frequency of the laser scanner is 50 Hz-200 Hz; in the second step, the fixed length of the first ring of the tunnel lining segment is 1.2m; in step eight, outputting perspective projection images of 25-35 frames per second.
The tunnel roaming video generation method based on the laser scanning data is characterized by comprising the following steps: in the sixth step, the visual angle is front view, left view, right view, overlook or look up, and a frame of perspective projection front view image, perspective projection left view image, perspective projection right view image, perspective projection overlook image or perspective projection upview image is generated; and step eight, continuously outputting the perspective projection images frame by frame according to the time sequence to generate a front-view roaming video, a left-view roaming video, a right-view roaming video, an overlook roaming video or an upward-view roaming video which are along the direction of the mileage of the tunnel and simulate the visual angle of human eyes.
The tunnel roaming video generation method based on the laser scanning data is characterized by comprising the following steps: in the sixth step, the visual angle is any three-dimensional visual angle of 360 degrees, and a frame of perspective projection image with any three-dimensional visual angle of 360 degrees is generated; and step eight, continuously outputting the perspective projection images frame by frame according to the time sequence to generate a 360-degree arbitrary three-dimensional visual angle roaming video which is along the tunnel mileage direction and simulates the human eye visual angle.
Compared with the prior art, the invention has the following advantages:
1. according to the invention, a 2D section spiral scanning mode of a laser scanner is utilized, a section point cloud with laser reflectivity on the inner wall of the tunnel is covered and collected in a moving mode along the mileage direction of the tunnel, an object in a visual range is projected to a single plane by using a perspective projection technology in a human eye visual 'big-end-near-little-end' effect, a frame-by-frame perspective projection image along the mileage direction of the tunnel is generated, illumination is not required, manual modeling is not required, the video definition is high, and the method is convenient to popularize and use.
2. According to the invention, the number of actual section point cloud scanning lines of one ring of tunnel lining segment is obtained, the tunnel environment is complex, the moving carrier speed cannot guarantee real-time uniformity, so that the number of section point cloud scanning lines is unevenly distributed, the theoretical value of the number of section point cloud scanning lines on the fixed length of one ring of tunnel lining segment is calculated according to the moving speed of the moving carrier and the sampling frequency of the laser scanner, the theoretical value of the number of section point cloud scanning lines is compared with the number of actual section point cloud scanning lines of one ring of corresponding tunnel lining segment, the number of section point cloud scanning lines with uneven number of actual section point cloud scanning lines of one ring of tunnel lining segment is subjected to interpolation processing, and each section point cloud scanning line which is evenly distributed along the tunnel mileage direction is obtained, so that each frame of perspective projection image data obtained in the later period is even and reliable, and the use effect is good.
3. When the laser scanner is installed, the instrument center of the laser scanner cannot be ensured to be positioned at the center of the tunnel section, so that the data of the collected scanning point coordinates of each section point cloud with the instrument center of the laser scanner as the circle center needs to be converted into the section scanning point coordinates with the center of the tunnel section as the circle center, and the image correction is realized.
4. The method has simple steps, obtains the reflection intensity information of the corresponding cross-section point cloud according to the laser reflectivity of each cross-section point cloud, performs circle center orthographic projection on the reflection intensity of the cross-section point cloud, obtains the gray value of each scanning point in the cross-section point cloud, generates an orthographic image of each ring of the tunnel lining segment by utilizing the laser reflection intensity information, gradually transits from the nearest visible distance to the farthest visible distance in the perspective range of the tunnel, performs perspective projection on each cross-section point cloud scanning line in the perspective range of the tunnel, corresponds the coordinates and the gray information of each cross-section point cloud scanning line in the perspective projection plane in the perspective range of the tunnel one by one to generate a frame of perspective projection image, a static sequence image, and fast and continuous display are performed to form a motion false image.
In summary, the invention utilizes the perspective projection technology to project the objects in the visual range to a single plane with the effect of human vision of 'near-large-far-small', generates the perspective projection images frame by frame along the direction of the mileage of the tunnel, displays the static sequence image images quickly and continuously, forms the false appearance of movement, can generate the roaming video by setting the image frame number moving every second, vividly displays the space perspective image of the objects, is intuitive, clear, real and high in efficiency, does not need illumination, does not need manual modeling, has high video definition, and is convenient for popularization and use.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
FIG. 1 is a block diagram of the process flow of the present invention.
FIG. 2 is a schematic view of a frame of perspective projection image according to the present invention.
Detailed Description
As shown in fig. 1 and fig. 2, a tunnel roaming video generation method based on laser scanning data according to the present invention includes the following steps:
step one, collecting laser scanning data of a tunnel wall: erecting a laser scanner on a movable carrier, setting the moving speed of the movable carrier, presetting the scanning resolution and sampling frequency of the laser scanner, covering the inner wall of a tunnel by using a 2D section spiral scanning mode of the laser scanner, moving and collecting section point clouds with laser reflectivity on the inner wall of the tunnel along the mileage direction of the tunnel, and taking the scanning point coordinate of each section point cloud as the center of a circle by using the center of the laser scanner;
in the embodiment, the moving speed of the moving carrier in the first step is 3 km/h-10 km/h; the scanning resolution of the laser scanner is 3-5; the sampling frequency of the laser scanner is 50 Hz-200 Hz.
It should be noted that, a 2D section spiral scanning mode of the laser scanner is used to cover the inner wall of the tunnel and move along the direction of the mileage of the tunnel to collect the section point cloud with laser reflectivity on the inner wall of the tunnel, and the perspective projection technology is used to project the objects in the visual range to a single plane with the effect of 'near-large-far-small' of human vision, so as to generate a frame-by-frame perspective projection image along the direction of the mileage of the tunnel, without illumination, without manual modeling, and with high video definition.
Step two, the interpolation calibration of the scanning line number of the point cloud of the cross section: calculating a theoretical value of the number of section point cloud scanning lines on one ring of fixed length of a tunnel lining segment according to the moving speed of a moving carrier and the sampling frequency of a laser scanner, comparing the theoretical value of the number of the section point cloud scanning lines with the number of actual section point cloud scanning lines of the corresponding tunnel lining segment, and performing interpolation processing on the number of the section point cloud scanning lines with uneven number of the actual section point cloud scanning lines of the tunnel lining segment to obtain each section point cloud scanning line with even distribution along the mileage direction of the tunnel;
in the second step, the fixed length of the first ring of the tunnel lining segment is 1.2m;
step three, acquiring the coordinates of a section scanning point and the diameter of the section by taking the center of the section of the tunnel as the circle center: performing robust estimation on the section point cloud scanning points after the section point cloud scanning line number interpolation calibration, eliminating rough difference points, and obtaining section scanning point coordinates and section diameters by using the center of the tunnel section as the center of a circle through circle center fitting processing;
the method includes the steps of acquiring the number of actual section point cloud scanning lines of a ring of tunnel lining segments, wherein due to the complex tunnel environment, the speed of a mobile carrier cannot guarantee real-time uniformity, and therefore uneven distribution of the number of section point cloud scanning lines is caused, calculating the theoretical value of the number of section point cloud scanning lines on the fixed length of the ring of tunnel lining segments according to the moving speed of the mobile carrier and the sampling frequency of a laser scanner, comparing the theoretical value of the number of section point cloud scanning lines with the number of actual section point cloud scanning lines of the ring of corresponding tunnel lining segments, and performing interpolation processing on the number of section point cloud scanning lines with uneven number of actual section point cloud scanning lines of the ring of tunnel lining segments to obtain each section point cloud scanning line which is evenly distributed along the mileage direction of a tunnel, so that each frame of perspective projection image data acquired in the later period is even and reliable, and the using effect is good.
When the laser scanner is installed, the instrument center of the laser scanner cannot be guaranteed to be located at the center of the tunnel section, so that data of collected scanning point coordinates of each section point cloud with the instrument center of the laser scanner as the circle center needs to be converted into section scanning point coordinates with the center of the tunnel section as the circle center, and correction of images is achieved.
Step four, obtaining gray information corresponding to the cross-section point cloud: acquiring reflection intensity information of the corresponding cross-section point cloud according to the laser reflectivity of each cross-section point cloud, and performing circle center orthographic projection on the reflection intensity of the cross-section point cloud to acquire a gray value of each scanning point in the cross-section point cloud;
fifthly, generating an orthographic image of each ring of the tunnel lining segment: constructing an image gray matrix according to gray information corresponding to each section point cloud scanning line on each ring of tunnel lining segment, and adding a geographic label to generate an orthophotograph of each ring of tunnel lining segment;
in this embodiment, the geographic labels in the fifth step include tunnel lining segment ring numbers, mileage, deformation, disease range, and facility equipment.
Step six, generating a frame of perspective projection image: selecting a visual angle, setting a visual field angle FOV and a closest visual distance and a farthest visual distance corresponding to different positions of the tunnel by taking human eyes as the visual angle, taking a projection plane corresponding to the farthest visual distance as a perspective projection plane of the perspective projection, and performing the perspective projection according to a formula
Figure BDA0002297440340000071
To obtain
Figure BDA0002297440340000072
Calculating the coordinate value rho of the point cloud scanning line coordinate of the ith section in the perspective range of the tunnel on the perspective projection plane i Wherein r is i Scanning line coordinates of the ith section point cloud in the perspective range of the tunnel, wherein l is the fixed distance between the visual angle point and the perspective projection plane i The distance between the viewing angle point and the section of the ith section point cloud scanning line in the perspective range of the tunnel;
gradually transitioning from the nearest visible distance to the farthest visible distance in the perspective range of the tunnel, carrying out perspective projection on each section point cloud scanning line in the perspective range of the tunnel, and corresponding coordinates and gray scale information of each section point cloud scanning line in the perspective projection plane in the perspective range of the tunnel one by one to generate a frame of perspective projection image;
step seven, the step six is circulated for multiple times, and perspective projection images of frames by frames along the mileage direction of the tunnel are generated until the moving carrier stops moving, and the laser scanner does not collect laser scanning data of the tunnel wall any more;
step eight, generating a roaming video along the direction of the mileage of the tunnel: and setting the number of frames of the perspective projection images output every second, continuously outputting the perspective projection images frame by frame according to the time sequence, and generating a roaming video which is along the direction of the mileage of the tunnel and simulates the visual angle of human eyes.
In step eight, outputting perspective projection images of 25-35 frames per second.
The method includes the steps of obtaining reflection intensity information of corresponding cross-section point clouds according to laser reflectivity of each cross-section point cloud, conducting circle center orthographic projection on the reflection intensity of the cross-section point clouds, obtaining gray values of all scanning points in the cross-section point clouds, generating an orthographic image of each ring of a tunnel lining segment by utilizing the laser reflection intensity information, gradually transitioning from a nearest visible distance to a farthest visible distance in a perspective range of a tunnel, conducting perspective projection on each cross-section point cloud scanning line in the perspective range of the tunnel, enabling coordinates of each cross-section point cloud scanning line in the perspective projection plane in the tunnel to correspond to gray information one by one, generating a perspective projection image, displaying static sequence image images in a rapid and continuous mode, forming motion artifacts, generating a roaming video by setting image frame number moving every second, displaying space perspective images of objects vividly, and displaying the space perspective images of the objects visually, clearly, truthfully and efficiently.
In this embodiment, the laser scanner in the first step is a three-dimensional laser scanner Faro or a Z + F9012 three-dimensional laser scanner.
In this embodiment, the viewing angle in the sixth step is front view, left view, right view, top view or top view, and a frame of perspective projection front view image, perspective projection left view image, perspective projection right view image, perspective projection top view image or perspective projection top view image is generated; and step eight, continuously outputting the perspective projection images frame by frame according to the time sequence to generate a front-view roaming video, a left-view roaming video, a right-view roaming video, an overlook roaming video or an upward-view roaming video which are along the direction of the mileage of the tunnel and simulate the visual angle of human eyes.
In this embodiment, the view angle in the sixth step is any three-dimensional view angle of 360 degrees, and a frame of perspective projection image of any three-dimensional view angle of 360 degrees is generated; and step eight, continuously outputting the frame-by-frame perspective projection images according to a time sequence to generate a 360-degree arbitrary three-dimensional view angle roaming video simulating the view angle of human eyes along the tunnel mileage direction.
According to the method, the roaming video is directly generated from the laser point cloud, so that the human input of 'segment modeling + block mapping' in the traditional modeling method is greatly reduced, and the current situation of the tunnel can be more intuitively reflected.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and any simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims (6)

1. A tunnel roaming video generation method based on laser scanning data is characterized by comprising the following steps:
step one, acquiring laser scanning data of a tunnel wall: erecting a laser scanner on a movable carrier, setting the moving speed of the movable carrier, presetting the scanning resolution and sampling frequency of the laser scanner, covering the inner wall of a tunnel by using a 2D section spiral scanning mode of the laser scanner, and moving and acquiring section point clouds with laser reflectivity on the inner wall of the tunnel along the mileage direction of the tunnel, wherein the scanning point coordinate of each section point cloud takes the center of the laser scanner as the circle center;
step two, the interpolation calibration of the scanning line number of the point cloud of the cross section: calculating a theoretical value of the number of section point cloud scanning lines on one ring of fixed length of a tunnel lining segment according to the moving speed of a moving carrier and the sampling frequency of a laser scanner, comparing the theoretical value of the number of the section point cloud scanning lines with the number of actual section point cloud scanning lines of the corresponding tunnel lining segment, and performing interpolation processing on the number of the section point cloud scanning lines with uneven number of the actual section point cloud scanning lines of the tunnel lining segment to obtain each section point cloud scanning line with even distribution along the mileage direction of the tunnel;
step three, acquiring the coordinates of a section scanning point and the diameter of the section by taking the center of the section of the tunnel as the circle center: performing robust estimation on the section point cloud scanning points after the section point cloud scanning line number interpolation calibration, eliminating rough difference points, and obtaining section scanning point coordinates and section diameters by using the center of the tunnel section as the center of a circle through circle center fitting processing;
step four, obtaining gray information corresponding to the cross-section point cloud: acquiring reflection intensity information of the corresponding cross-section point cloud according to the laser reflectivity of each cross-section point cloud, and performing circle center orthographic projection on the reflection intensity of the cross-section point cloud to acquire a gray value of each scanning point in the cross-section point cloud;
fifthly, generating an orthographic image of each ring of the tunnel lining segment: constructing an image gray matrix according to gray information corresponding to each section point cloud scanning line on each ring of tunnel lining segment, and adding a geographic label to generate an orthophotograph of each ring of tunnel lining segment;
step six, generating a frame of perspective projection image: selecting a visual angle, setting a visual field angle FOV and a closest visual distance and a farthest visual distance corresponding to different positions of the tunnel by taking human eyes as the visual angle, taking a projection plane corresponding to the farthest visual distance as a perspective projection plane of the perspective projection, and performing the perspective projection according to a formula
Figure FDA0002297440330000021
To obtain
Figure FDA0002297440330000022
Calculating the coordinate value rho of the point cloud scanning line coordinate of the ith section in the perspective range of the tunnel on the perspective projection plane i Wherein r is i The point cloud scanning line coordinate of the ith section in the perspective range of the tunnel, wherein l is the fixed distance between a viewing angle point and a perspective projection plane i The distance between the viewing angle point and the section of the ith section point cloud scanning line in the perspective range of the tunnel;
gradually transitioning from the nearest visible distance to the farthest visible distance in the perspective range of the tunnel, carrying out perspective projection on each section point cloud scanning line in the perspective range of the tunnel, and corresponding coordinates and gray scale information of each section point cloud scanning line in the perspective projection plane in the perspective range of the tunnel one by one to generate a frame of perspective projection image;
step seven, the step six is circulated for multiple times, and a perspective projection image frame by frame along the mileage direction of the tunnel is generated until the moving carrier stops moving, and the laser scanner does not collect laser scanning data of the tunnel wall any more;
step eight, generating a roaming video along the direction of the mileage of the tunnel: and setting the number of frames of the perspective projection images output every second, continuously outputting the perspective projection images frame by frame according to the time sequence, and generating a roaming video which is along the direction of the mileage of the tunnel and simulates the visual angle of human eyes.
2. The method for generating tunnel roaming video based on laser scanning data according to claim 1, characterized in that: and in the first step, the laser scanner is a three-dimensional laser scanner Faro or a Z + F9012 three-dimensional laser scanner.
3. The method for generating tunnel roaming video based on laser scanning data according to claim 1, characterized in that: and fifthly, the geographic label comprises a tunnel lining segment ring number, mileage, deformation, a disease range and facility equipment.
4. The method for generating tunnel roaming video based on laser scanning data according to claim 1, characterized in that: the moving speed of the moving carrier in the first step is 3 km/h-10 km/h; the scanning resolution of the laser scanner is 3-5; the sampling frequency of the laser scanner is 50 Hz-200 Hz; in the second step, the fixed length of a tunnel lining segment ring is 1.2m; in step eight, outputting perspective projection images of 25-35 frames per second.
5. The method for generating tunnel roaming video based on laser scanning data according to claim 1, characterized in that: in the sixth step, the visual angle is front view, left view, right view, overlook or look up, and a frame of perspective projection front view image, perspective projection left view image, perspective projection right view image, perspective projection overlook image or perspective projection upview image is generated; and step eight, continuously outputting the perspective projection images frame by frame according to the time sequence to generate a front-view roaming video, a left-view roaming video, a right-view roaming video, an overlook roaming video or an upward-view roaming video which are along the direction of the mileage of the tunnel and simulate the visual angle of human eyes.
6. The method for generating tunnel roaming video based on laser scanning data according to claim 1, characterized in that: in the sixth step, the visual angle is any three-dimensional visual angle of 360 degrees, and a frame of perspective projection image with any three-dimensional visual angle of 360 degrees is generated; and step eight, continuously outputting the perspective projection images frame by frame according to the time sequence to generate a 360-degree arbitrary three-dimensional visual angle roaming video which is along the tunnel mileage direction and simulates the human eye visual angle.
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