CN101750015B - Gravel pit earth volume measuring method based on digital image technology - Google Patents

Abstract

A sandstone pit earthwork measurement method based on digital image technology uses a palm computer, a GPS receiver and a digital camera to realize digital collection and recording of field information. In the field survey, firstly the GPS receiver lays out the control points and collects the three-dimensional coordinates of the control points; the software running on the handheld computer receives the GPS positioning results in real time through the GNSS network, and generates the GPSPoint point layer and the bunker boundary layer; select the appropriate Set up a benchmark at the control point, and place two signs on the benchmark as the photo control point; use a digital camera to take pictures of the sandstone pit and the benchmark; after the field work is over, upload the photos and field data to the internal data Processing system; based on the control point layer, use a single photo to calculate the photo information, and then obtain the three-dimensional coordinates of the internal points of the sandstone pit through three-dimensional relative settlement; construct a triangular network model of the sandstone pit, and calculate the triangular network model , to get the depth of the gravel pit and the amount of earthwork.

Description

Earthwork Measurement Method of Sandstone Pit Based on Digital Image Technology

technical field

The invention relates to a method for measuring the earth volume of a sandstone pit, in particular to a method for measuring the earthwork volume of a sandstone pit based on digital image technology, and belongs to the technical field of land management electronic information.

Background technique

With the acceleration of the country's urbanization and the development of various construction projects, the speed of sand and gravel mining in my country has gradually accelerated, but most of them are small and medium-sized. From the mid-to-late 1990s to the beginning of this century, with the acceleration of my country's urbanization process, especially the rapid development of infrastructure construction such as real estate and roads, large, medium and small cities have a huge market demand for sand and gravel. The phenomenon of sand mining continues to intensify, reaching a state of out-of-control for a time, and the characteristics of corporatization, scale and mechanization of sand excavation behavior are very obvious. The existence of sandstone pits not only deteriorates the ecological environment and destroys valuable land resources, but also has adverse effects on urban construction, urban management and land planning. Therefore, it is very important to control and restore sandstone pits.

The investigation of the current situation of sandstone pits by means of existing technology mainly includes the depth and scale of sandstone pits and the earthwork volume of sandstone pits. From the analysis of accuracy, production cycle, production cost and restrictive conditions, there are obvious deficiencies:

(1) Aerial laser scanner (aerial LIDAR): The LIDAR system is usually equipped with a CCD camera when working, and collects 3D data of ground points along the design route of the survey area. After the data is acquired, it can be processed to obtain the orthophoto and Ground elevation model (DEM). The accuracy of LIDAR ground acquisition is quite high, the production cycle is relatively short, and it is less constrained by meteorological conditions than aerial photography. However, the production cost is still relatively high, and it is generally suitable for large-area topographic surveys.

(2) Ground laser scanner (ground LIDAR): Ground LIDAR adopts a non-contact high-speed laser measurement method. The scanner emits laser light on the target. According to the time difference between laser emission and reception, the distance between the corresponding measured point and the scanner is calculated. Then, according to the step angle distance values in the horizontal and vertical directions, the three-dimensional coordinates of the measured points are calculated in real time, that is, the array geometry data of terrain and three-dimensional surfaces of complex objects are obtained in the form of point clouds. The precision is very high, the equipment is easy to operate, and the degree of automation is high. However, the production cost is high, and compared with aviation LIDAR, the laser power of ground LIDAR is much smaller, so its maximum measurement distance is mostly about 300m (under the condition that the reflectivity is greater than 80%), and the ground reflectivity is usually less than 20%. It is lower in the bunker.

(3) Field measurement: In the field measurement, GPS control points are first laid out, GPS satellite receivers are used to collect control point data, and total stations are used to supplement the data of points that cannot be collected by GPS, so as to measure efficiently and at low cost Topographic changes in the corresponding part of the sand pit. However, this kind of field measurement will have incomplete and inaccurate data collection. For example, terrain changes such as ditches, ridges, embankments, slopes, etc. have no or few points on the top and no points on the bottom, and are also affected by the weather and environment.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a method for measuring earthwork in sandstone pits based on digital image technology, using close-range photogrammetry technology, mainly using handheld computers and digital cameras, based on GPS/RTK and dual The sign pole realizes the automation of field collection, eliminating the need for total station layout and collection points. The equipment is simple, easy to operate, and the production cycle is short, which greatly reduces the workload of the field and reduces the cost.

In order to achieve the above object, the technical solution adopted by the present invention is: a method for measuring earthwork in sandstone pits based on digital image technology, which is characterized in that:

(1) GNSS network for global satellite positioning;

(2) Field data acquisition system: including handheld computers, digital cameras, and GPS/RTK devices with operating systems of Windows Mobile 5.0 and above and field data acquisition software installed;

(3) Office data processing system: a computer equipped with office data processing software and hardware, including .NET Framework2.0 and installed with an office data processing system;

Firstly, carry out field survey, set up control points on the edge of the sandstone pit according to the topography of the sandstone pit, run the field software on the handheld computer, receive the GPS positioning results in real time through the GNSS network, display them on the handheld computer in real time and save them in the field software In the GPSPoint point layer, then take the GPSPoint point layer on the screen, and connect the arranged control points in sequence to form a bunker boundary layer, which is saved in the PDA; select the control points, and put these control points As photo control points, set up double marker poles on these photo control points, use a digital camera to take pictures of the sandstone pit depression area and double marker poles, upload the photos and field data to the internal data processing system, According to the GPSPoint point layer and photos, the information of a single photo is solved, and then the three-dimensional coordinates of the points inside the sandstone pit are obtained through the three-dimensional image pair. The network model is used to calculate the depth of the sandstone pit and the amount of earthwork.

The above method can be carried out according to the following specific steps:

(1) Image map import: the office data processing system downloads the map data by accessing the map database, imports the data into the handheld computer of the field data acquisition system through the data line, and navigates to the sandstone pit site;

(2) Collection of sandstone pit boundary control point information: Set up control points at the boundary feature points of the sandstone pit, and the field software running on the handheld computer receives GPS positioning results in real time through the GNSS network and displays them on the handheld computer in real time. These points are automatically saved in the GPSPoint point layer of the field software, and then the GPSPoint point layer is taken on the screen and connected in sequence to form a bunker boundary layer, which is saved in the PDA; select the control point as the photo control Points, these photo control points should ensure that four photo pairs are formed, and the internal points of the sandstone pit depression can be obtained through these four photo pairs. Two measurement marks are arranged on the pole of the point;

(3) On-the-spot photography with a digital camera: The digital camera shoots a stereoscopic image pair from a direction that can reflect the topography inside the sandstone pit. The shooting angle of the stereoscopic image pair should be greater than 45° and less than 135°, and the sandstone pit should be in the middle of the photo. location, and each photo contains at least three double-signposts. As the photography direction changes, the signage should be able to face the photography direction in time to improve the imaging effect of the signage;

(4) The field software running on the handheld computer saves all space and attribute information as a shapefile format file until the field data collection is completed;

(5) Field data is imported into the internal data processing system: the control point layer generated by the field collection and the digital photos taken by the digital camera are imported into the internal data processing system through the data line;

(6) Calculation of photo information for a single photo: Based on the GPSPoint point layer, use the two-dimensional plane coordinates of the photo control points on the photo and the three-dimensional space coordinates collected in the field, and use the theory of photogrammetry to calculate the digital photo The inner orientation element of the photo, the outer orientation element and the distortion coefficient of the photo, wherein the outer orientation element includes the photography position parameters X _S , Y _S , Z _S and the photography attitude parameters ω, κ, the internal orientation elements include the focal length f of the objective lens and the image coordinates x ₀ and y ₀ of the principal point of the photo image (both are 0 in this algorithm), and the principal point of the photo image is the center of the objective lens on the photo Perpendicular point, the distortion coefficient of the objective lens is k ₁ ;

(7) Stereo image pairs to calculate the coordinate information of points inside the sandstone pit: according to some feature points inside the sandstone pit, use the front intersection principle of the stereo image pair to calculate the spatial three-dimensional coordinates of these feature points, and these feature points are stored in the sandstone pit. In the point layer inside the pit, together with the bunker boundary layer obtained from the field, the data (TIN) for constructing the irregular triangular network model are composed;

(8) Calculation of earthwork volume: According to the data collected in the field and the data processed in the office, the first phase TIN is constructed by using the boundary points of the sandstone pit, and the internal points of the sandstone pit are inserted under the first phase TIN to establish the second phase TIN. The two phases of TIN are subtracted to obtain the earth volume of the sand and gravel pit, and the depth of the sand and gravel pit can be obtained.

Advantage of the present invention and remarkable effect:

(1) Innovatively designed a new method of earthwork measurement for sandstone pits, mainly using handheld computers and digital cameras, supplemented by GPS/RTK and dual signs, to realize the full digital collection and recording of field information, field equipment Simple and low workload. The handheld computer can display the GPS positioning information in real time, and record and save the boundary point layer of the sandstone pit; the sandstone pit photos taken by the digital camera can provide rich information about the sandstone pit, which can be obtained by using a single photo and a stereo image pair to solve The 3D coordinates of the point inside the sandpit.

(2) Innovatively designed the form of "one pole with double marks" in the field collection, that is, two measurement signboards are arranged on the pole erected at one control point. This method can not only reduce the number of control points. , while improving the measurement accuracy.

(3) Innovatively designed the office data processing system, combined with the base map information of the handheld computer, the photo control point layer obtained by GPS/RTK, and comprehensively processed the digital photos in the office system to obtain the sandstone pit The internal points, and then construct the triangular network model of the sandstone pit, and calculate the earthwork volume, which is simple and convenient.

The present invention can be applied to the following fields or industries:

(1) Used by the planning department for land planning;

(2) The land department is used for the treatment and repair of sandstone pits;

(3) Department of Land and Resources for mineral calculations.

Description of drawings

Fig. 1 is the system connection schematic diagram of the inventive method;

Figure 2 is a schematic diagram of field data collection;

Fig. 3 is a data flow diagram of the present invention.

Detailed ways

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, the earthwork measurement method based on close-range photogrammetry technology has

(1) GNSS network for global satellite positioning;

(2) Field data acquisition system: a handheld computer with Windows Mobile 5.0 and above operating system and field data acquisition software installed, a digital camera, and a set of GPS/RTK equipment;

Office data processing system: a computer with .NetFramework 2.0 installed with the office data processing system.

Before field measurement, configure the parameters and network connection of the handheld computer deployed with field data acquisition software; when performing field measurement, set up control points, run the field software on the handheld computer, and receive data in real time through the GNSS network The GPS positioning results are displayed on the handheld computer in real time. These points are automatically saved in the GPSPoint point layer of the field software, and then the points are taken on the screen and connected in sequence to form a bunker boundary layer, which is saved on the PDA. Middle; choose a suitable control point to set up a benchmark, and place two signs on the benchmark, that is, "one pole with double marks" as the photo control point; use a digital camera to take pictures of the sandstone pit and the sign; after the field work is over , upload the photos and field data to the internal data processing system; based on the GPSPoint point layer, use a single photo to calculate the photo information, and then obtain the three-dimensional coordinates of the internal points of the sandstone pit through three-dimensional relative settlement; construct a sand pit TIN model of the stone pit, calculate the TIN model to obtain the depth and earth volume of the sandstone pit.

As shown in Figure 2, the field data collection process of the present invention is:

First, control points are set up, and the field software running on the handheld computer receives GPS positioning results in real time through the GNSS network, and displays them on the handheld computer in real time. These points are automatically saved in the GPSPoint point layer of the field software, and then screened Take points and connect them sequentially to form a bunker boundary layer and save it in the PDA; according to the on-site measurement, the field software running on the handheld computer can obtain the GPSPoint point layer and the bunker boundary layer of the bunker; Choose a suitable control point to set up a benchmark, and place two signs on the benchmark as control points for photos; use a digital camera to take pictures of the sandstone pit and the sign; repeat the above steps until the field work is completed. In the actual test, 13 control points were set up, and the field software running on the handheld computer received the positioning results of these 13 control points in real time through the GNSS network, and obtained their three-dimensional coordinates; select point 1, point 2, point 3 Point No. 4, Point 5, Point 7, Point 10, Point 12 and Point 13 are used as identification points (photo control points), and double signposts are erected on these points; Take pictures of it at different angles, and take pictures of pairs. This experiment obtained four pairs of images. Each photo of the first pair of images includes point 1, point 2, point 3 and point 4. The second pair of images Each photo of the pair contains point 3, point 4, point 5 and point 7, each photo of the third pair contains point 7, point 4, point 10 and point 12, and the fourth Each photo of the object pair contains point 12, point 10, point 13 and point 4.

As shown in Figure 3, the method of the present invention specifically includes the following steps:

(1) Image map import: the office data processing system accesses the map database, downloads the map data, imports the data into the handheld computer of the field data acquisition system through the data line, and navigates to the sandstone pit site.

(2) Collection of sandstone pit boundary control point information: Set up control points on the boundary feature points of the sandstone pit, and the field software running on the handheld computer receives the GPS positioning results in real time through the GNSS network and displays them on the handheld computer in real time. These points are automatically saved in the GPSPoint point layer of the field software, and then the points are taken on the screen and connected in sequence to form a bunker boundary layer, which is saved in the PDA, and the appropriate control point is selected to set up a benchmark. Lay out double signboards as photo control points.

(3) On-the-spot photography with a digital camera: The digital camera shoots a stereoscopic image pair from a direction that can reflect the topography inside the sandstone pit, and the shooting angle of the stereoscopic image pair should be greater than 45° and less than 135°. The gravel should be in the middle of the photo, and each photo should contain at least three double marker posts. As the direction of photography changes, the signage should be able to face the direction of photography in time to improve the imaging effect of the signage.

(4) The field software running on the handheld computer saves all space and attribute information as a shapefile until the field data collection is completed.

(5) Field data is imported into the internal data processing system: the control point layer generated by field collection and the digital photos taken by the digital camera are imported into the internal data processing system through the data line.

ω、κ，内方位元素包括影物镜焦距f和像片像主点的图像坐标x₀、y₀(在该算法中二者均为0)，像片像主点为物镜中心在像片上的垂足点。物镜畸变系数为k₁。(6) Calculation of photo information for a single photo: Based on the GPSPoint point layer, use the two-dimensional plane coordinates of the photo control points on the photo and the three-dimensional space coordinates collected in the field, and use the theory of photogrammetry to calculate the digital photo The inner orientation element of the , the outer orientation element of the photo, and the distortion factor. Among them, the outer orientation elements include photography position parameters X _S , Y _S , Z _S and photography attitude parameters

ω, κ, the internal orientation elements include the focal length f of the objective lens and the image coordinates x ₀ and y ₀ of the principal point of the photo image (both are 0 in this algorithm), and the principal point of the photo image is the center of the objective lens on the photo Foot point. The distortion coefficient of the objective lens is k ₁ .

(7) Stereo image pairs to calculate the coordinate information of points inside the sandstone pit: according to some feature points inside the sandstone pit, use the front intersection principle of the stereo image pair to calculate the spatial three-dimensional coordinates of these feature points, and these feature points are stored in the sandstone pit. In the point layer inside the pit, together with the bunker boundary layer obtained from the field, the data for constructing the triangulation model is composed.

(8) Calculation of earthwork volume: According to the data collected in the field and the data processed in the office, the boundary points of the sandstone pit are used to construct the first phase of the irregular triangular network model TIN, and the internal points of the sandstone pit are inserted under the first phase of TIN to establish In the second phase of TIN, the two phases of TIN are subtracted to obtain the earth volume of the sandstone pit and the depth of the sandstone pit.

Claims (2)

1. gravel pit earth volume measuring method based on Digital image technology is characterized in that being provided with:

(1) is used for the GNSS network of global positioning satellite;

(2) field data acquisition system: comprise that operating system is Windows Mobile 5.0 and above version and palm PC, digital camera, the GPS/RTK equipment that the field data acquisition software is installed;

(3) interior industry data handling system: industry data processing software and hardware in being provided with comprises .NET Framework2.0 and the interior computing machine of data handling system already is installed;

At first carrying out field operation measures, according to sandstone hole landform, lay the reference mark at the sandstone pit edge, operate in the field data acquisition software of palm PC, receive the GPS positioning result by the GNSS network real-time, be presented on the palm PC in real time and be kept in the GPSPoint point diagram layer of field data acquisition software; Then GPSPoint point diagram layer is carried out screen and get a little, the reference mark of being laid is connected in order successively, constitute border, sand pit line chart layer, be kept in the palm PC; Select the reference mark, these reference mark as picture control point, on these picture control points, set up the double-flag bar, with digital camera cave in district and double-flag bar of sandstone holes taken pictures, with photo and field data acquisition data upload to interior industry data handling system, according to GPSPoint point diagram layer and photo, resolve individual photo information; Resolve the three-dimensional coordinate that obtains sandstone hole internal point by stereogram at last, utilize border, sandstone hole line chart layer file to set up triangulation network model, triangulation network model is calculated, obtain the sandstone hole degree of depth and earth volume.

2. according to the described gravel pit earth volume measuring method of claim 1, it is characterized in that according to the following steps based on Digital image technology:

(1) at first, striograph is imported, interior industry data handling system is downloaded map datum by the access chart database, and these data are imported in the palm PC of field data acquisition system by data line, and it is on-the-spot to navigate to the sandstone hole; Gather sandstone hole boundary Control dot information, boundary characteristic point place in the sandstone hole lays the reference mark, the field data acquisition software that operates in palm PC receives the GPS positioning result by the GNSS network real-time, and be presented in real time on the palm PC, these points are kept in the GPSPoint point diagram layer of field data acquisition software automatically;

(2) then, GPSPoint point diagram layer is carried out screen get a little, connect successively in order, constitute border, sand pit line chart layer, be kept in the palm PC; Select the reference mark as picture control point, it is right that these picture control points should guarantee to constitute four photo pictures, to obtaining the internal point of caving in and distinguish in the sandstone hole, set up the double-flag bar by these four photo pictures, promptly on the mark post of a picture control point, lay two survey mark boards at picture control point; Take pictures on the spot with digital camera, digital camera is cheated the direction of inner landform and is taken stereogram from reflecting sandstone, the camera angle of forming stereogram should be greater than 45 ° and less than 135 °, the sandstone hole should be in the centre position of photo, and comprise three double-flag bars in every photo at least, along with the variation of photography direction, the survey mark board should be able in time positively be aimed at photography direction, to improve the label imaging effect; The field data acquisition software that operates in palm PC saves as the shapefile formatted file with all spaces and attribute information, finishes until the field data collecting work; The digital photo that the control point diagram layer and the digital camera of field data acquisition generation are taken pictures imports interior industry data handling system by data line; Based on GPSPoint point diagram layer, utilize the two dimensional surface coordinate on photograph of picture control point and the three dimensional space coordinate of field data acquisition, utilize photogrammetric Theory, calculate the elements of interior orientation of digital photo, the elements of exterior orientation and the distortion factor of photo, wherein, elements of exterior orientation comprises the camera positions parameter X _S, Y _S, Z _SWith the photography attitude parameter

ω, κ, elements of interior orientation comprise the image coordinate x of shadow objective focal length f and photo principal point ₀, y ₀, x ₀, y ₀Be 0, the photo principal point is the intersection point point of object lens center on photo, and the object lens distortion factor is k ₁

(3) last, according to the inner unique point of getting of appointing in the sandstone hole, utilize the forward intersection principle of stereogram, calculate the 3 d space coordinate of these unique points, these unique points are kept in the inner point diagram layer in sand pit, form the data that make up the TIN model jointly with border, the sand pit line chart layer that field operation obtains; Data according to field data acquisition data and the processing of interior industry, utilize sandstone hole frontier point to make up first phase TIN model, under first phase TIN model, insert sandstone hole internal point, set up second phase TIN model, the value of two phase TIN models is subtracted each other, thereby try to achieve gravel pit earth volume, and can obtain the degree of depth in sandstone hole.

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