KR101021013B1 - A system for generating 3-dimensional geographical information using intensive filtering an edge of building object and digital elevation value - Google Patents

Abstract

PURPOSE: A system for generating 3D geographical information by using boundary strengthening filtering and altitude information is provided to correct altitude information between a building object and a ground surface through planarization work. CONSTITUTION: A border intensifying filtering unit(120) performs boundary strengthening filtering about a boundary of a 2D building object among impermeable ground information. An altitude information calculating unit(140) calculates altitude information from aerial LIDAR(Light Detection And Ranging) information. A 3D object information generator(150) obtains 3D building object information. Based on planarization coordinate information, a planarization unit(170) corrects altitude information of the 3D building object.

Description

A SYSTEM FOR GENERATING 3-DIMENSIONAL GEOGRAPHICAL INFORMATION USING INTENSIVE FILTERING AN EDGE OF BUILDING OBJECT AND DIGITAL ELEVATION VALUE}

The present invention relates to a three-dimensional geographic information generation system.

As the imaging sector is gradually transitioning from 2D to 3D, the ripple effect of related fields using it is growing rapidly, and the application fields of 3D imaging are gradually diversifying from the public sector, defense sector and general industry. One of these applications, the 3D Geographical Information (GI) software industry market has been segmented and developed by function, and the diversity and expertise of using geographic information is based on Geographical Information System (GIS) technology. Contributed to the creation of applications.

Generally, 3D geographic information system (GIS) is a geographic information system applying 3D modeling technology. It builds terrain and artificial facilities as 3D information, and stores, processes, and stores spatial information in conjunction with geographic information system and augmented reality technology. It is a system to process and analyze. In order to construct three-dimensional geographic information data in such a three-dimensional geographic information system, conventionally modeling three-dimensional geographic information data by hand drawing, digitizing, etc. of artificial facilities such as buildings and roads, and the modeled results Inconvenient to flatten three-dimensional geographic information.

In addition, the conventional three-dimensional geographic information construction process costs more than the modeling of two-dimensional geographic data when modeling the three-dimensional geographic information data, using the latest survey equipment such as Mobile Mapping System (MMS) The construction of three-dimensional geographic data also cost a lot. In addition, the conventional three-dimensional geographic information construction process has a disadvantage that it is difficult to match the construction time with digital aerial photography information, aerial lidar information and three-dimensional geographic information data.

In order to solve the above problems, the present invention is to provide a method for automatically generating flattened 3D geographic information, buildings, and road numerical layers using only aerial lidar information and digital aerial photography information.

In addition, the present invention is to provide a method for obtaining flattened coordinate information to generate flattened three-dimensional geographic information.

The present invention obtains impervious surface information from the digital aerial photography information in the digital aerial photography information storage unit using the normalized urbanization index, and uses a boundary enhancement filter for the boundary of the two-dimensional building object among the impervious surface information. Filter, but highlight the saturation using RGB (Red, Green, Blue) band emphasis and IHS (Intensity, Hue, Saturation) color conversion for the part of the impervious surface information. A boundary reinforcement filtering unit for dividing a boundary of the two-dimensional building object; An elevation information calculation unit configured to calculate elevation information from the aerial lidar information in the aerial lidar information storage unit, wherein the elevation information indicates numerical altitude data corresponding to the two-dimensional building object; A 3D object information generation unit for obtaining 3D building object information by using the spatial coordinate information of the filtered 2D building object and the calculated elevation information; Extracts a plurality of specific coordinate information from the 3D building object information, wherein the specific coordinate information has a brightness value of a region indicated by the specific coordinate information within a preset area larger than a brightness value of regions indicated by neighboring coordinate information Indicates coordinate information in a case, obtains flattened coordinate information by using distance information and angle information between the plurality of specific coordinate information, and based on the flattened coordinate information having the lowest height coordinate value among the flattened coordinate information, the 3D The elevation information of the building object is modified, wherein the preset area represents one divided grid area when the entire area in the image is divided into grids having the same size, and the brightness value represents an average pixel value of pixels in the area. Indicating a flattening performing unit; And a three-dimensional image output unit displaying three-dimensional geographic information generated by using the modified elevation information of the three-dimensional building object, wherein the impervious surface information is obtained using a normalized urbanization index. Provide a 3D geographic information generation system.

Further, in the present invention, the flattening coordinate information may be obtained when the distance information between the plurality of specific coordinate information is smaller than a preset distance threshold and the angle information between the plurality of specific coordinate information is larger than a preset angle threshold. Characterized in that it is obtained.

In addition, in the present invention, the predetermined distance threshold is 5m, and the predetermined angle threshold is 45 degrees.

Accordingly, the present invention can obtain flattening coordinate information using only aerial lidar information and digital aerial photography information, and flattened by modifying the elevation information of the building object based on the flattening coordinate information having the lowest altitude coordinate value among the flattening coordinate information. Three-dimensional geographic information can be obtained. Through this flattening operation, it is possible to prevent the building object from being positioned on the protruding ground surface by correcting an elevation difference between the building object and the ground surface, thereby generating more clear three-dimensional geographic information. In addition, the cost for constructing existing three-dimensional geographic information can be reduced.

1 is an embodiment to which the present invention is applied and shows a schematic structure of a flattened three-dimensional geographic information generation system.
2 is an embodiment to which the present invention is applied and shows a result of performing automatic outline vectorizing on a building object.
3 is an embodiment to which the present invention is applied and is shown to explain a process of generating 3D object information using 2D object information and elevation information in the 3D object information generating unit.
FIG. 4 is a diagram for explaining a process of obtaining flattening coordinate information by using a distance and an angle difference between specific coordinate information, which is a characteristic of an elevation change of an object, as an embodiment to which the present invention is applied.
FIG. 5 is a flowchart illustrating a process of generating three-dimensional geographic information using flattening coordinate information according to an embodiment to which the present invention is applied.

Hereinafter, with reference to the accompanying drawings illustrating the configuration and operation of the embodiment of the present invention.

In addition, the configuration and operation of the present invention described by the drawings will be described as one embodiment, by which the technical spirit of the present invention and its core configuration and operation is not limited.

In addition, the terms used in the present invention are as widely used as possible now

Phosphorus terms were selected, but specific cases will be described using terms arbitrarily selected by the applicant. In such a case, since the meaning is clearly described in the detailed description of the part, it should not be interpreted simply by the name of the term used in the description of the present invention, and it should be understood that the meaning of the term should be interpreted. . In particular, in the present specification, information is a term encompassing values, parameters, coefficients, elements, and the like, and in some cases, the meaning may be interpreted differently.

Geographic Information System (GIS) is an information system that integrates and processes geographic data that occupies spatial location and related attribute data, and efficiently collects, stores, updates, processes, analyzes, and analyzes various types of geographic information. It can be defined as the collective organization of hardware, software, geographic data, and human resources used for printing. According to the use of the geographic information system, it is easy to use a variety of spatial information. In addition, it is possible to generate three-dimensional geographic information on the target area by using information on a predetermined level of facilities, aerial photographs, and digital topographic maps. It became possible. Therefore, the embodiments using only aerial lidar information and digital aerial photography information to generate more efficient three-dimensional geographic information.

1 is an embodiment to which the present invention is applied and shows a schematic structure of a flattened three-dimensional geographic information generation system.

 Referring to FIG. 1, the planarized 3D geographic information generation system includes a data storage unit 110, a boundary enhancement filtering unit 120, a two-dimensional object information generation unit 130, and an elevation information extraction unit 140. The dimensional object information generating unit 150, the flattening coordinate information obtaining unit 160, the flattening performing unit 170 and the 3D image output unit 180.

First, the data storage unit 110 is composed of a digital aerial photography information storage unit 111 and an aerial lidar data storage unit 112, the digital aerial photography information storage unit 111 is digital from the outside The aerial photograph information is received and stored, and the aerial lidar information storage unit 112 receives and stores aerial lidar information from the outside.

Here, digital aerial photography information means two-dimensional coordinate information and attribute information that can be obtained from the aerial photography. For example, ground coordinates are calculated for internal facial expression information, a variable used when calculating the physical coordinate system of a camera, and mutual expression information, a variable used when generating a stereoscopic model, from a pixel coordinate system of an aerial photograph. When the absolute facial expression information, the mutual facial expression, and the absolute facial expression work are completed, the external facial expression element, which is a constant of the equation used to calculate a ground coordinate value corresponding to an arbitrary position on the aerial photograph, may be included. have.

 The aviation lidar information refers to three-dimensional data information associated with the point where the aviation laser surveying system is mounted on the aircraft to scan a laser pulse on the ground surface and is reflected using the arrival time of the reflected laser wave. For example, the position coordinate value by the laser survey, the rotation error information of the X-axis or Y-axis generated during the aerial laser survey, the coordinate value of the entry point of the aerial laser survey data and the distance information of the outermost ground survey coordinate value of the building, There may be scale correction factors, constant height difference information between ground reference points and aerial laser survey data.

The 2D coordinate information and the attribute information of the image of the specific area may be extracted from the digital aerial photography information storage unit 111. The impervious paper surface information may be extracted from the 2D coordinate information and the attribute information of the image of the specific region by using a normalized difference built-up index (NDBI) according to Equation 1 below.

Here, Band X represents the spectral band range of 1.55 to 1.75 μm, and Band Y represents the spectral band range of 0.76 to 0.90 μm.

The boundary enhancement filtering unit 120 may perform an image enhancement operation for extracting a building object and a road object from the impervious surface information extracted using the normalized urbanization index according to Equation 1 above. First, roads are darker than buildings, so saturation can be emphasized using RGB band emphasis and IHS conversion. In addition, boundary enhancement filtering may be applied to the building object and the road object to clarify the boundary of the object. The filtering coefficient α (3 × 3) for the boundary enhanced filtering is expressed by Equation 2 below.

In addition, after the boundary between the building object and the road object is clarified using the filtering coefficient α of Equation 2, the boundary enhancement filtering unit 120 removes noise that cannot become a building and a road.

The two-dimensional object information generation unit 130 generates two-dimensional building object information and road object information by removing noise that cannot be a building and a road, and performing automatic contour outline vectorization on the building object having a clear boundary. can do. The result of performing automatic outline vectorizing on the building object can be seen in FIG. 2.

Meanwhile, the elevation information extraction unit 140 may extract elevation information based on plane coordinates by using three-dimensional data information obtained from the LIDAR data storage unit 112. The three-dimensional object information generation unit 150 uses two-dimensional building object information and road object information generated from the two-dimensional object information generation unit 130, and elevation information extracted from the elevation information extraction unit 140. 3D building object information and road object information. This will be described in more detail with reference to FIG. 3.

The 3D object information generation unit 150 may extract only specific coordinate information that is a feature of elevation change of the object from the synthesized 3D building object information and road object information. For example, the coordinate information of the point where the brightness value rapidly changes from the building object information and the road object information may be extracted as specific coordinate information. That is, it may mean a coordinate that is significantly larger or smaller than the brightness value of neighboring coordinates in a certain area. Here, the remarkably large or small degree may be determined according to a preset threshold. Alternatively, the specific coordinate information indicates coordinate information when a brightness value of an area indicated by the specific coordinate information in a preset area is greater than a brightness value of areas indicated by coordinate information neighboring thereto. Herein, the predetermined area may mean one divided grid area when the entire area of the image is divided into grids having the same size, or may mean an area having a similar distribution of brightness values that can be estimated as one object. have. The brightness value represents an average pixel value of the pixels in the corresponding area. The specific coordinate information may be coordinate information indicating a boundary line of a building, or may indicate coordinate information of a point at which a road crosses.

The flattened coordinate information obtaining unit 160 may obtain flattened coordinate information from the specific coordinate information by using a distance and an angle difference between the specific coordinate information. This will be described in detail with reference to FIG. 4. Further, by using the flattening coordinate information, the flattening operation may be performed on the building object information or the road object information to generate a more precise numerical map.

The planarization performing unit 170 may planarize based on the planarization coordinate information of the building object and the road object generated from the planarization coordinate information acquisition unit 160 and the 3D data information obtained from the air lidar information storage unit 112. You can do it. In this case, the building object may modify the altitude coordinate value of the building object based on the flattening coordinate information having the lowest altitude coordinate value among the flattening coordinate information. This flattening operation compensates for the elevation difference between the building object and the ground surface, thereby preventing the building object from being positioned on the protruding surface, and by generating the flattened building object information, more precise three-dimensional geographic information can be generated. It becomes possible.

The generated 3D geographic information may be displayed through the 3D image output unit 180.

3 is an embodiment to which the present invention is applied and is shown to explain a process of generating 3D object information using 2D object information and elevation information in the 3D object information generating unit.

As shown in FIG. 1, the 3D object information generation unit 150 generates 3D object information using 2D object information and elevation information. Referring to FIG. 3, the 2D object information 151 generated from the 2D object information generator 130 may include spatial coordinate information and object property information. The spatial coordinate information indicates two-dimensional spatial coordinate information of the object, and may mean, for example, X coordinates and Y coordinates indicating the position of the object in the image. The object property information represents unique property information of the object. For example, when the object is a building, it may mean a building name, a floor number, an address, and the like.

The elevation information extracted from the elevation information extraction unit 140 may refer to the numerical elevation model 152. Digital Elevation Model (DEM) refers to a narrow meaning model that deals only with elevation in digital terrain model that geometrically reproduces and numerically interprets the information of discontinuities observed on the surface through data processing. It can be called a digital elevation model, a digital elevation model, or a digital elevation data. The numerical elevation model 152 represents elevation information based on plane coordinates using three-dimensional data information obtained from the LIDAR data storage unit 112. Here, the elevation information means numerical altitude data, and the 3D data information has been described with reference to FIG. 1.

Accordingly, the three-dimensional object is synthesized by synthesizing the two-dimensional object information 151, that is, the X coordinate and Y coordinate information indicating the position of the image object and the elevation information, that is, the numerical elevation data of the position corresponding to the X coordinate and Y coordinate. Information 153 may be generated. Only the specific coordinate information that is a feature of the elevation change of the object is selected from the three-dimensional building object information generated in this way, and the flattening coordinate information may be obtained by using the distance and angle difference between the specific coordinate information. Hereinafter, a detailed embodiment of obtaining flattening coordinate information will be described with reference to FIG. 4.

FIG. 4 is a diagram for explaining a process of obtaining flattening coordinate information by using a distance and an angle difference between specific coordinate information, which is a characteristic of an elevation change of an object, as an embodiment to which the present invention is applied.

First, in FIG. 4, the solid line represents a set of points having the same altitude, and among them, the position where the change of the brightness value is the greatest, that is, A (x1, y1, z1), B (x2, y2, Suppose there are three positions z2) and C (x3, y3, z3). In this case, the flattened coordinate information may be extracted by using a distance and an angle difference between the three specific coordinate information.

If the distance between coordinates A and B is referred to as Dab, and the distance between coordinates A and C is referred to as Dac, Dab and Dac may be obtained by Equation 3 below.

When the angle of coordinate B is Φ 1 and the angle of coordinate C is Φ 2 based on the coordinate A, Φ 1 and Φ 2 may be obtained by Equation 4 below.

The distance between the two coordinates is smaller than the distance threshold by comparing the Dab, Dac and Φ1, Φ2 calculated using Equations 3 and 4 with a preset distance threshold and a preset angle threshold, respectively. If the angle formed by the coordinates is larger than the angle threshold, the coordinates may be set as flattening coordinate information. This is because the distance between the two coordinates is smaller than the preset distance threshold and the angle formed by the two coordinates is larger than the preset angle threshold means that the change of the terrain is large. Here, the preset distance threshold is preferably 1 m to 5 m, and the preset angle threshold is preferably 30 degrees to 45 degrees. The flattening coordinate information generated as described above may be used by the flattening performing unit 170 to perform the flattening operation.

FIG. 5 is a flowchart illustrating a process of generating three-dimensional geographic information using flattening coordinate information according to an embodiment to which the present invention is applied.

First, digital aerial photography information may be extracted from the digital aerial photography information storage 111 (S510). Here, the digital aerial photography information may mean two-dimensional coordinate information and attribute information of an image of a specific area. The impervious surface information may be extracted from the 2D coordinate information and the attribute information of the image of the specific region by using a normalized difference built-up index (NDBI) (S540). Then, filtering is performed on the boundary of the building object in the impervious surface information using the boundary enhancement filter (S550).

After the boundary enhancement filtering is performed, two-dimensional building object information may be generated by removing noise that cannot be a building and performing automatic edge outline vectorization on the building object having a clear boundary (S560).

Meanwhile, the airborne lidar information may be extracted from the airborne lidar data storage unit 112 (S520), and the elevation information based on plane coordinates may be extracted from the airborne lidar information (S530). ).

The 2D building object information and the elevation information may be synthesized into 3D building object information (S570). In operation S580, only specific coordinate information that is a feature of elevation change of an object may be extracted from the synthesized 3D building object information. The flattening coordinate information may be obtained by using a distance and an angle difference between the specific coordinate information. The distance information and the angle information of the specific coordinate information may be compared with a predetermined distance threshold value and a predetermined angle threshold value, respectively (S581). In this case, when the distance between the two coordinates is smaller than the distance threshold value, and the angle formed by the two coordinates is larger than the angle threshold value, the corresponding coordinates may be set as flattening coordinate information. In operation S582, elevation information of the building object may be modified using the flattening coordinate information of the building object. In this case, the building object may be flattened based on the coordinate information having the lowest altitude value among the flattened coordinate information. Through the flattening operation, an elevation difference between the building object and the ground surface can be corrected, and by generating the flattened building object information, more precise three-dimensional geographic information can be generated (S590). The generated 3D geographic information may be displayed as a 3D image.

As described above, in order to generate three-dimensional geographic information, the present invention has to be modeled by manual drawing, digitizing, and the like, and flattened again from the modeled result. By obtaining the flattening coordinate information by using the dimensional object information and the elevation information obtained from the aerial lidar information, and performing the flattening operation by modifying the elevation information of the building object based on the flattening coordinate information having the lowest altitude coordinate value. 3D geographic information can be generated conveniently and at low cost.

As mentioned above, preferred embodiments of the present invention are disclosed for purposes of illustration, and those skilled in the art can improve and change various other embodiments within the spirit and technical scope of the present invention disclosed in the appended claims below. , Replacement or addition would be possible.

Claims (3)

The impervious surface information is acquired from the digital aerial photography information in the digital aerial photography information storage unit by using the normalized cityization index, and filtering is performed by using a boundary enhancement filter on the boundary of the two-dimensional building object among the impervious surface information. In the impervious surface information, the part representing the road and the part representing the road by emphasizing saturation using RGB (Red, Green, Blue) band emphasis and IHS (Intensity, Hue, Saturation) color conversion, and the two-dimensional building A boundary enhancement filtering unit for classifying the boundary of the object;
An elevation information calculation unit configured to calculate elevation information from the aerial lidar information in the aerial lidar information storage unit, wherein the elevation information indicates numerical altitude data corresponding to the two-dimensional building object;
A 3D object information generation unit for obtaining 3D building object information by using the spatial coordinate information of the filtered 2D building object and the calculated elevation information;
A plurality of specific coordinate information is extracted from the 3D building object information, wherein the specific coordinate information includes coordinate information in which a brightness value of an area indicated by the specific coordinate information in a preset area is adjacent to an area indicated by the specific coordinate information. Coordinate information in the case of greater than the brightness value of the pointing area, the flattening coordinate information is obtained by using the distance information and angle information between the plurality of specific coordinate information, and the flattening coordinate having the lowest altitude coordinate value of the flattening coordinate information The elevation information of the three-dimensional building object is modified based on the information, wherein the preset area represents one divided grid area when the entire area of the image is divided into grids having the same size, and the brightness value represents the area. A flattening performer indicating an average pixel value of pixels in the pixel; And
3D image output unit for displaying the 3D geographic information generated by using the elevation information of the modified 3D building object
Including,
The impervious surface information is three-dimensional geographic information generation system, characterized in that obtained by using the normalized urbanization index.
(Where normalized urbanization index = {(1.55 ~ 1.75μm)-(0.76 ~ 0.90μm)} / {(1.55 ~ 1.75μm) + (0.76 ~ 0.90μm)} The method of claim 1,
The flattening coordinate information may be obtained when the distance information between the plurality of specific coordinate information is smaller than a preset distance threshold and the angle information between the plurality of specific coordinate information is larger than a preset angle threshold. 3D geographic information generation system. The method of claim 2,
And the predetermined distance threshold is 5m, and the predetermined angle threshold is 45 degrees.

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