RU2591875C1 - Method of constructing map of exogenous geological processes of area along route of main oil line - Google Patents

Abstract

FIELD: laser engineering.

SUBSTANCE: invention relates to production of topographic data on the Earth surface relief according to aerial photography and laser scanning area from board of aircraft, particularly to monitoring of main oil pipeline route sections (MP) for detecting signs of exogenous geological processes (EGP) and fixation of boundaries thereof. In method of constructing map EGF area along route MN digital aerial photography and air laser scanning. That is combined with collecting and recording of navigation data for generating and recording coordinates of points of flight trajectory. Processing data of aircraft laser scanning and navigation data. Obtaining cloud laser reflections and on basis of their automatic classification with interactive correction of results of constructing digital elevation model (DEM) area. According to DEM formed in construction surface inclination angles derivatives map slopes area. Simultaneously with construction of DEM data is processed digital aerial photography. Using results of constructing digital elevation model, maps slopes and orthophotomap area is detection and formation of map EGP flowing on area along route MN.

EFFECT: technical result is high accuracy of detecting and determining EGP with reduction of labour intensity and duration of inspection.

1 cl, 1 dwg, 1 tbl

Description

The invention relates to the field of obtaining topographic information about the topography of the earth's surface and objects located on it using aerial photographs and laser scanning data from the aircraft, in particular, to monitoring sections of the route of the main oil pipeline (ML) of overhead and underground laying with difficult geological conditions for identify and track sections of the route with signs of exogenous geological processes (EGP) and fixation of their boundaries, including those beyond Assy MN and hidden vegetation.

There is a method of creating orthophotomaps based on aerial video materials [patent for the invention RU 2235292 C2, publ. 08/27/2004, IPC: G01C 11/30], which includes the implementation of aerial video, converting an analog video to digital or recording a digital video to a computer and creating electronic block editing. After this, editing of electronic block editing and design of phototriangulation units, measurement of stereo pairs and rejection of erroneous data, construction and adjustment of phototriangulation units, registration of images, formation of orthophotos and orthophotomaps are carried out. Electronic block editing is created by orienting the next frame relative to all overlapping and previously processed images. The design of phototriangulation blocks is performed automatically using all geometric relationships that satisfy the specified criteria. The construction and adjustment of phototriangulation blocks is performed with automatic rejection of erroneous data.

There is also known a method for diagnosing the condition of product pipelines [patent for the invention RU 2281534 C1, publ. 08/10/2006, IPC: G01V 8/00], in which scanning the territory of the product pipeline by means of thermal imaging and visual imaging with thermal imaging cameras from the aircraft, laser spatial scanning of the terrain on the territory of the product pipeline, the current positioning of the aircraft by flight and navigation means, recording data of thermal and visual surveys and laser spatial scanning of the area with reference to the data of the current positioning of the aircraft, the formation of an integrated model of the thermal and visual image of the surface of the product pipeline and interpretation of image data of the surface of the product pipeline. Scanning the territory of the product pipeline by means of thermal imaging and visual surveys is carried out by cyclic rotation of the direction of optical visualization relative to the axis located perpendicular to the direction of flight. Data is recorded discretely in single-frame mode at the moments of the vertical position of the camera optical axes by the team of the digital and topological relief model formation unit.

The closest analogue of the claimed invention is a method of forming a digital model of the terrain and / or orthomosaic [patent for invention RU 2216711 C1, publ. November 20, 2003, IPC: G01C 11/00, G03B 37/00], which consists in the fact that a digital camera aerial photographs the terrain and form digital images, determine the navigation and navigation data of the aircraft carrier on which the digital apparatus is installed, in the form of its coordinates at the time of aerial photography and form an orthophotomap. Simultaneously with aerial photography, the area is scanned with a laser beam, the first digital terrain model (DEM) is formed according to the obtained laser scanning data. From the obtained set of laser scanning points, points are identified that belong to favorable areas for a given reliability. According to the first DEM and the data of points related to favorable regions, a topological relief model is formed, the points of the topological model are selected in the coordinate system of each digital image to obtain data on favorable regions on it. Then, all these digital images are divided into pairs to be mutually oriented with the formation of stereo pairs, and stereo models are formed by determining the corresponding points in the favorable areas of each of the digital images of these stereo pairs. Correction of the external orientation of the stereo model is carried out according to the data of the generated topological model. As a result, taking into account the obtained data, an orthophotomap is formed.

The disadvantage of the closest analogue is the lack of the ability to build a map of the slopes of the terrain and to determine the DEM, the map of the slopes and the orthoplan of the manifestations of EGP, the allocation of their location and boundaries.

The objective of the claimed invention is the reliable detection of EGP on the highway MN and fixing their boundaries.

The technical result achieved by using the claimed invention is to increase the accuracy of identifying and determining the location of the EGP for building a map of the EGP of the terrain along the MN route while reducing the laboriousness and timing of the examinations.

This problem is solved, and the technical result is achieved by the fact that in the method of constructing an EGP map of the terrain along the ML route, digital aerial photography and airborne laser scanning of the terrain along the ML route from the aircraft are performed to obtain an array of laser reflection points and digital aerial photographs of the terrain, simultaneously with digital aerial photography and airborne laser scanning collect and record navigation data received from the ground-based navigation system, on-board navigation system in of an airborne vessel and an inertial navigation system of a laser scanner to generate and record the coordinates of the flight path points, process the data of an air laser scan and obtain a cloud of laser reflection points from the processing results and the formed coordinates of the flight path points, based on the automated classification of which a digital model of the terrain is built, conduct interactive correction of the results of automated classification and record the corrected c digital elevation models, transmit data on a digital elevation model to a block for constructing derived surfaces of slope angles and form a map of terrain slopes, simultaneously with the digital elevation model, digital aerial photographs are processed: initial non-transformed images are selected, the latter are aligned and ortho-converted in tone-aligned images according to the terrain with the formation of the orthomosaic of the area, using the results of constructing a digital model p terrain, maps of slopes and orthoimages of the area, identify and determine the boundaries of exogenous geological processes (EGP) that occur on the terrain along the MN route, based on the selection of previously saved EGP standards and compare them with the construction results and, based on the identified EGP boundaries, form an EGP map of the area along the highway MN.

The invention is illustrated by the drawing, which shows a block diagram of the claimed method of constructing a map of EGP terrain along the highway MN and the positions indicated:

1 - digital aerial photography;

2 - navigation;

3 - airborne laser scanning;

4 - data processing of airborne laser scanning;

5 - digital aerial photography data processing;

6 - storage of EGP standards;

7 - selection of EGP standards;

8 - comparison of the results of processing of the VLANs and CAFS with the standards of EGP;

9 - formation of the EGP map;

Work on airborne laser scanning (VLS) and digital aerial photography (CAFS) is carried out during engineering surveys for the design and construction of MN objects (linear part, including sections of crossings over natural and artificial obstacles, oil pumping stations) in order to obtain relevant cartographic information about relief and terrain objects for identifying and tracking previously identified sections of the route with signs of EGP.

The claimed method of constructing a map of EGP terrain along the highway MN is as follows.

Identifying and fixing the EGP boundaries on the MN path includes performing aerial laser scanning (3) to obtain a cloud of laser reflection points and digital aerial photography (1) to obtain digital aerial photographs, determining the current coordinates of the aircraft carrier (2), calculated on the basis of simultaneous measurements of ground stations GLONASS / GPS, the GLONASS / GPS airborne complex and inertial system, cameral processing for creating a digital orthophotomap (5), a digital elevation model (4), the surfaces of the slope angles derived from it, and also decryption of materials obtained as a result of cameral processing. According to the invention, decryption is carried out under the conditions of a complex analysis of data obtained as a result of desk processing based on the developed standards: using the results of constructing a digital elevation model, a map of slopes and an orthoimage of the area, exogenous geological processes (EGP) occurring on the area along the MN route are identified based on selecting (7) previously saved (6) EGP standards and comparing (8) them with the construction results, based on the identified EGPs, ormirovanie (9) EGP maps of the area along the route of MN.

Aerial photographing of the terrain is carried out by means of aerial survey equipment mounted on board an aircraft (airplane, helicopter), including an aerial camera, an air laser scanner (LIDAR) and an antenna and a GLONASS / GPS receiver. Aerial photography parameters must satisfy the requirements for constructing orthophotomaps with a scale of 1: 2000 or larger, the density of laser reflection points must be at least 4 points per 1 square meter, the resolution of aerial photographs must be at least 8 cm per pixel, and the resolution of thermal imaging images must be at least 1 m per pixel .

Deciphering airborne laser scanning materials is a fairly new method for examining pipelines for permafrost assessment, which is little used for cryoliotozone studies. The resulting materials and their processing provide information that is not available on digital orthophotomaps. For example, polygonal or convex permafrost forms covered with forest are surely recorded on slope (KU) maps and a digital elevation model.

The advantages of airborne laser scanning are:

- remote and automated receipt of information;

- high planned and vertical accuracy of determining the position of the points of laser reflections (TLO);

- Obtaining terrain data on forested areas.

With the advent of global positioning systems (GLONASS, GPS), the possibility of precise geo-referencing of data received from the aircraft appeared. Improving the accuracy parameters of laser ranging and inertial systems has led to the possibility of determining the coordinates of points on the earth’s surface by direct measurement, using multisensor devices - air laser scanners.

Airborne laser scanning is aimed at obtaining three-dimensional coordinates of objects using measurements of LIDAR systems using the technology of obtaining and processing information about distant objects using active optical systems using the phenomena of light reflection and scattering in transparent and translucent media. A pulsed laser scanner installed on an aircraft (airplane, helicopter) performs a discrete scan of the earth's surface and objects located on it, registering the direction of the laser beam and the propagation time of the pulse from the moment it is emitted until it is received after reflection from the earth's surface.

During the aerial survey flight, the scanner, due to the rectilinear movement of the aircraft and rotation in the transverse direction of the mirror of the sensor unit, surveys the underlying surface, emitting powerful and short optical (laser) pulses in its direction. The operation of the laser scanner is based on measuring the slant range D from the radiation source (laser) to the ground object, which is an obstacle to the propagation of the laser beam. Such an obstacle causes the appearance of a reflected pulse, which will be detected by the optical photodetector of the scanner, and by the delay time from the moment of radiation of the probe pulse to the registration of the reflected pulse, taking into account the constancy of the propagation speed of electromagnetic waves (speed of light), one can determine the range D. Simultaneously with the inertial the system, the measuring sensor of which is rigidly connected with the optical-mechanical device of the scanner, the orientation angles of the probe Beam and coordinates of the spatial position of the carrier through the use of an onboard receiver of the global navigation satellite system (GLONASS / GPS), operated in a differential mode of measurement, which together with the GLONASS / GPS receiver mounted on the base station receives navigational information. The inertial sensor is located inside the body of the scanning system, the internal positioning parameters (offset parameters) are determined by the equipment manufacturer and are used by the standard data processing software included in the system kit. The antenna of the GLONASS / GPS receiver integrated into the scanner is located in the upper part of the fuselage of the aircraft; its position relative to the scanner is unchanged throughout the entire duration of the project.

Knowing the parameters of exterior orientation and distance allows you to mathematically go to the coordinates of the point that caused the reflection. The results obtained from the joint processing of laser data, data from an inertial navigation system and receivers of a global navigation satellite system are an array of irregularly located points for which the spatial coordinates and intensity of the reflected signal are known — a laser-location image or a “cloud” of laser points. The laser-location image is always discrete, it consists of many points of laser reflections (TLOs), distributed uniformly over the surface of the earth and objectively reflecting the topology of the earth's surface and ground objects. Such data is accumulated on the built-in digital media of the on-board computer.

An important feature of laser scanners, in addition to the accuracy and detail of the information received, is the possibility of laser pulses penetrating under the crowns of trees and obtaining several reflected pulses for one emitted (if there are various objects on the surface to be examined, such as trees, buildings, power lines and others).

At the same time, digital aerial photography of the underlying surface is performed with a digital aerial camera rigidly fastened to the optical-mechanical scanner unit, with the possibility of recording terrain images in the visible, infrared or thermal range of electromagnetic radiation. Aerial photographs and files with information on the response time of the shutter of the lens are recorded on the built-in digital media of the on-board computer. Geospatial binding of aerial photographs to airborne laser scanning data is performed using elements of the exterior orientation of the aerial camera and time stamps of the shutter speed of the lens. The camera shutter pulse is fed to the input of the GLONASS / GPS receiver to record (with an accuracy of 1 µs) the time taken to capture the image, and accordingly the external orientation parameters for each aerial photographs.

In addition to color photographs from the aircraft, it is possible to obtain images in other spectral ranges of electromagnetic radiation, such as infrared (IR) or ultraviolet. The presence of accompanying IR images allows you to get additional information about the geomorphological structure of the Earth’s surface.

Thus, airborne laser scanning technology allows you to receive (after data processing) the following set of digital data:

- the aircraft trajectory with an accuracy of about 10 cm (in the presence of ground GLONASS-GPS stations and at a distance of no more than 30 km from the aircraft from any of them);

- an array of georeferenced points of laser reflections of a given accuracy and detail;

- An array of digital geo-referenced photographs of a given resolution.

The obtained data of digital aerial photography and airborne laser scanning are used to calculate the trajectory of the aircraft and its orientation in the software of the LIDAR system, the initial array of points of reflection of the laser beam, as well as the initial array of aerial photographs. According to the GLONASS / GPS receiver, the global coordinates system WGS-84 recalculates the received coordinates of the transformer into the coordinate system adopted for the final work and the creation of cartographic materials.

The construction of a high-precision digital elevation model (DEM) is carried out only by the points of laser reflections from the surface of the earth, the classification of which is carried out automatically. After obtaining the preliminary results of the classification, they are checked and adjusted in an interactive mode. Automated classification of TLW should be carried out with the obligatory creation of the following classes of points: "land", "vegetation", "buildings", "wires and elevated structures", "other points". The final materials of the automated classification are subjected to a verification check, during which the correctness of the assignment of certain points to the corresponding class is evaluated and additional adjustment of the results is performed.

The construction of a DEM is performed automatically by the Delaunay triangulation method. DTM is built only using points of the class "ground" with the obligatory interactive correction of the results of automated classification.

The results of constructing a high-precision digital elevation model are stored both in a regular-cellular form (GRID) and in the form of models based on the use of an irregular network of triangles (TIN). The algorithm for constructing a digital elevation model should ensure accuracy that is appropriate to the scale of the survey and transmit the main morphostructural features of the terrain, as well as adequately express small erosion and technogenic relief forms.

The DTM constructed in this way is a surface for projecting digital aerial photographs in order to obtain orthophotomaps from space-oriented aerial photographs based on exterior orientation elements calculated according to the aircraft’s flight path and relative orientation parameters (offset parameters) of an air laser scanner, aerial cameras, and onboard GNSS antenna, located on the fuselage of the aircraft.

Digital aerial photographs are linked to airborne laser scanning data by synchronizing the aperture of the aerial camera shutter and the laser pulse recording time.

Based on the obtained high-precision digital elevation model generated from the laser reflection points of airborne laser scanning and navigation complex measurements, the specialized software calculates the derived surfaces of the slope angles and constructs a map of the slopes of the terrain, as well as an exposure map of the slopes, watercourses and watersheds.

The technology for creating digital orthophotomaps consists of the following main steps:

- classification of laser reflection points;

- selection of source untransformed images;

- performing tone alignment of the original untransformed images;

- orthorectification of images according to the terrain, optimal selection and placement of stitching lines between orthorectified images, and cropping at predetermined boundaries on each sheet of layout;

- registration of orthophotomaps as a final product.

A comprehensive analysis of digital orthophotomaps, digital terrain models and derived surfaces of slope angles obtained as a result of cameral processing is performed on the basis of the developed standards presented in Table 1.

The EGP standards developed on the basis of airborne laser scanning data and verified by orthophotomaps are compared with the obtained slope maps, a digital elevation model, and orthophotomaps. The comparison results are recorded on the orthomosaic or other thematic map. Based on the results of applying all identified EGPs, a map of the distribution of EGPs is formed.

Using the data of airborne laser scanning and digital aerial photography to construct digital orthophotomaps, digital elevation models, and derived surfaces of slope angles, it is possible to identify exogenous geological processes occurring on the MN track and to outline the identified relief forms according to the developed standards, including large sizes that go beyond the boundary of the route MN, and evaluate their development over time.

A comprehensive analysis of the constructed data reveals exogenous geological processes, including those hidden by vegetation. By direct decoding signs of vegetation, the state and activity of the examined area with the presence of EGP are estimated:

- identification and determination of the types of EGP;

- definition and fixing the boundaries of the development of EGP;

- assessment of the possible impact of each EGP on the object of the MN;

- identification of newly formed and the development of previously defined EGP during subsequent work on the VLANs and CAFS;

- identification of deformations or broken thermal insulation layer in sections of the overhead installation of MN.

Air laser scanning materials are suitable for accurate determination of the geometric parameters of objects, including for determining the height of the stand in any place of the designed pipeline, the supports of overhead power lines, and their deviations from the design ones. In combination with thermal imaging, the detection of flooded areas and water barriers is possible without conducting field decryption with on-site visits.

The construction of a high-precision digital elevation model with increased detail serves as the basis for many derived maps: slope maps, slope exposure maps, and others necessary during design. Increased detailing of the relief helps to identify dangerous landforms not only in the land allotment strip of the MN route, but also in the corridor of greater width, thereby assessing the possible development of dangerous geological processes.

The construction of three-dimensional terrain models according to airborne laser scanning and their analysis allows us to carry out pre-design and design solutions, monitor territories in the zone of interest, and simulate emergency situations.

Claims (1)

A method of constructing a map of exogenous geological processes (EGP) of the terrain along the route of the main oil pipeline (MN), which consists in the fact that they perform digital aerial photography and airborne laser scanning of the terrain along the MH route from the aircraft to obtain an array of laser reflection points and digital aerial photographs of the terrain, simultaneously with digital aerial photography and airborne laser scanning, the navigation data collected and received from the ground navigation system is collected and recorded, on-board navigation Aircraft system and inertial navigation system of the laser scanner to generate and record the coordinates of the flight path points, process the data of the air laser scan and obtain the cloud of laser reflection points from the processing results and the formed coordinates of the flight path points, based on the automated classification of which a digital elevation model is built terrain, conduct interactive correction of the results of automated classification and record ck the corrected digital elevation model, transmit data on the digital elevation model to the block for constructing the derived surfaces of the slope angles and form a map of the terrain slopes, simultaneously with the digital elevation model, they process the data of digital aerial photography: they select the initial untransformed images, perform tone alignment of the latter and orthorectification aligned according to the tone of the images according to the terrain with the formation of the orthoimage of the area, using the results of construction a digital elevation model, a map of slopes and an orthographic map of the area, identify and determine the boundaries of exogenous geological processes (EGP) that occur on the terrain along the MN route, based on the selection of previously saved EGP standards and compare them with the results of construction and by the identified EGP boundaries, they map EGP terrain along the highway MN.

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