KR102165985B1 - Implicit terrain data creation method and electronic apparatus for performing the method - Google Patents

Abstract

A method of generating implicit terrain data and an electronic device performing the method relates to a method and an electronic device for generating implicit terrain data capable of minimizing the size of data while maintaining geographic quality from original terrain data.

Description

TECHNICAL FIELD The method of generating implicit terrain data and an electronic device that performs the method thereof TECHNICAL FIELD [Implicit TERRAIN DATA CREATION METHOD AND ELECTRONIC APPARATUS FOR PERFORMING THE METHOD]

The following description relates to a method for generating implicit terrain data and an electronic device that performs the method, and more particularly, to generate implicit terrain data based on a method of interpolating an implicit surface using a basic function.

Recently, digital maps are widely used in cars, ships, airplanes, etc. for location verification. In addition, digital maps are used in various application systems based on Geographical Information Systems (GIS), and the digital map data stored in the storage device is processed through a computer to form a three-dimensional terrain, and the terrain is displayed using a display device. Express.

The digital map is represented by topographic modeling, and representatively, a digital elevation model (DEM) or a contour line model can be used. The digital elevation model expresses the digital terrain by interpolating between a given height value (altitude) at equally spaced grid points. And, the digital contour model expresses the terrain by interpolating between contour lines.

The digital contour model has the advantage of having a very small data size compared to the digital elevation model, but has a disadvantage of being inaccurate. On the other hand, the digital altitude model is acquired by reading aerial photographs or satellite images, and data of various resolutions are provided according to the interval between grid points. The precision of the terrain is determined by the spacing of the grid points, so it ultimately depends on the resolution of the digital elevation model. The high-resolution terrain data is precise, but the required data size is very large, and the low-resolution terrain data is the opposite.

Digital maps are difficult to actively use for high-resolution terrain data due to the limitations of computer resources that depend on to provide terrain. In particular, computer resources installed in a mobile means such as a car, ship, airplane, etc., where digital maps are widely used, are very limited, making it difficult to operate large amounts of data.

An object of the present invention is to provide a terrain modeling method that is invented to solve the above problems, and greatly reduces the size of stored data while maintaining the quality of the original terrain data.

Another object of the present invention is to provide a terrain modeling method that minimizes the management and operation of terrain model data having various resolutions.

A method of generating implicit terrain data according to an embodiment includes the steps of constructing implicit terrain data from original terrain data; Lossless compressing the implicit terrain data; Reconstructing the losslessly compressed implicit terrain data; And lossy compressing the reconstructed implicit terrain data.

In the constructing step according to an embodiment, implicit terrain data may be constructed by using a height value for a node constituting the original terrain data.

Lossless compression according to an embodiment may include extracting initial feature nodes from nodes of the implicit terrain data; Generating an implicit surface of implicit terrain data by interpolating the initial feature nodes; And sequentially adding feature nodes using the original terrain data and the calculated implicit surface.

The initial feature nodes according to an embodiment are nodes that are first set among implicit terrain data according to an interpolation method for generating an implicit surface, and the added feature nodes are the height values of the nodes of the original terrain data and the implicit surface. It may be a node added for the purpose of reducing a preset tolerance due to comparison between height values.

The implicit surface according to an embodiment may include an initial feature node representing a preset height value and a height value of an arbitrary point through interpolation between the initial feature nodes.

The determining step according to an embodiment is to compare the height values of the nodes constituting the original terrain data with the height values of the implicit surfaces calculated by interpolating the initial feature nodes, so that the height error is A node having the height value of the original terrain at a large point can be added to the implicit surface as a feature node.

The reconstructing step according to an embodiment comprises reconstructing losslessly compressed implicit terrain data through rearrangement of the order of the added feature nodes using a feature line representing a central axis to which feature points are connected in the original terrain data, and the feature The line may be generated by analyzing the original topographic data and connecting the feature points constituting the valley and the ridge.

The reordering according to an embodiment may rearrange the order of feature nodes in proportion to a distance between the feature line and the added feature node.

In the lossy compression step according to an embodiment, the size of the implicit terrain data may be reduced by sequentially removing the feature nodes from the order of the rearranged feature nodes from the reconstructed implicit terrain data.

The method for generating implicit terrain data according to an embodiment may further include converting the loss-compressed implicit terrain data into a mesh form and visualizing it.

In the visualizing step according to an embodiment, the height value of each node is extracted according to the resolution by calculating the implicit terrain data, and the three-dimensional coordinates of each node are interconnected to generate a mesh, and then the texture is mapped to the generated mesh. Can be visualized.

An electronic device for generating implicit terrain data according to an embodiment, the electronic device comprising a processor, the processor generating implicit terrain data by using a height value of a node constituting the original terrain data; Lossless compression using nodes of the implicit terrain data; Reconstructing the losslessly compressed implicit terrain data; And lossly compressing the reconstructed implicit terrain data using the original terrain data and the implicit terrain data.

Lossless compression according to an embodiment includes extracting initial feature nodes from the implicit terrain data; Generating an implicit surface of implicit terrain data by interpolating the initial feature nodes; And sequentially adding feature nodes using the original terrain data and the calculated implicit surface.

The implicit surface according to an embodiment may include an initial feature node representing a preset height value and a height value of an arbitrary point through interpolation between the initial feature nodes.

The determining step according to an embodiment is to compare the height values of the nodes constituting the original terrain data with the height values of the implicit surfaces calculated by interpolating the initial feature nodes, so that the height error is A node having the height value of the original terrain at a large point can be added to the implicit surface as a feature node.

The reconstructing step according to an embodiment comprises reconstructing losslessly compressed implicit terrain data through rearrangement of the order of the added feature nodes using a feature line representing a central axis to which feature points are connected in the original terrain data, and the feature The line may be generated by analyzing the original topographic data and connecting the feature points constituting the valley and the ridge.

The reordering according to an embodiment may rearrange the order of feature nodes in proportion to a distance between the feature line and the added feature node.

In the lossy compression step according to an embodiment, the size of the implicit terrain data may be reduced by sequentially removing the feature nodes from the order of the rearranged feature nodes from the reconstructed implicit terrain data.

The electronic device according to an embodiment may further include converting the loss-compressed implicit terrain data into a mesh form and visualizing it.

In the step of visualizing according to an embodiment, the height value of each node is extracted according to the resolution by calculating the implicit terrain data, and the three-dimensional coordinates of the nodes of each node are interconnected to generate a mesh, and then texture on the generated mesh. Can be visualized by mapping.

The method of generating implicit terrain data and the electronic device performing the method perform lossless compression and lossy compression using the implicit terrain data, thereby maintaining the geographic quality of the original terrain data to the maximum and the size of the data used as the implicit terrain data. Can be minimized.

The method of generating implicit terrain data and the electronic device performing the method interpolates the implicit surface of the implicit terrain data without the need for a separate process in response to the terrain having the resolution of the original terrain data. It is possible to create implicit terrain data more conveniently without management.

1 is a diagram illustrating an electronic device generating implicit terrain data according to an exemplary embodiment.
2 is a flow chart illustrating a method of generating implicit terrain data according to an embodiment.
3 is a diagram illustrating feature lines and feature nodes of implicit terrain data according to an embodiment.
4 is a diagram illustrating implicit terrain data in a mesh form according to an exemplary embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating an electronic device generating implicit terrain data according to an exemplary embodiment.

Referring to FIG. 1, the electronic device 101 may read original terrain data generated from contour lines, aerial photographs, and satellite images. The original terrain data may be digital altitude data in which altitude values according to the terrain are expressed. In addition, the electronic device 101 may extract nodes constituting the original terrain data.

The electronic device 101 may generate implicit terrain data based on the original terrain data. Specifically, the electronic device 101 may set a node constituting the original terrain data as a node of the implicit terrain data. In other words, the electronic device 101 may map 3D coordinates representing each node of the original terrain data to a node of the implicit terrain data.

The electronic device 101 may perform lossless compression on the generated implicit terrain data. Specifically, lossless compression may be a compression method for setting initial feature nodes from implicit terrain data. In addition, lossless compression may be a compression method in which feature nodes are added by interpolating set initial feature nodes and applying a greedy algorithm according to an implicit surface.

Lossless compression may determine an implicit surface by interpolating at least four or more initial feature nodes initially set for lossless compression among the generated implicit terrain data. In the lossless compression, the height value of the node of the original terrain data and the height value of the implicit surface can be compared to determine a case where the error of the height value is greater than a preset tolerance. In addition, when lossless compression is greater than a tolerance, a feature node having a height value for a node of the original terrain data may be added.

In other words, the fact that the error of the height value is greater than the allowable error may mean that when the set at least four or more initial feature nodes are interpolated, the actual height value of the terrain cannot be obtained. This may mean that there is a topographic difference between the original topographic data and the implicit topographic data. Accordingly, the electronic device 101 may add a feature node calculated to be similar to the topography of the original topographic data to the implicit surface in consideration of a case in which the error of the height value is large.

In the end, lossless compression adds feature nodes so that the interpolated implicit surface based on the initial feature nodes included in the implicit terrain data is similar to the original terrain, so that the final interpolated implicit surface is the same height value as the nodes of the original terrain data. It is possible to generate implicit terrain data that calculates.

The electronic device 101 may reconstruct losslessly compressed implicit terrain data. Specifically, the electronic device 101 may rearrange the order of the feature nodes according to the distance between the feature lines and feature nodes constructed from the original terrain data. In addition, the electronic device 101 may reconstruct the implicit terrain data by rearranging the order of the feature nodes.

In addition, the electronic device 101 may perform lossy compression using a feature node of the reconstructed implicit terrain data. In detail, the electronic device 101 may perform lossy compression for removing some of the feature nodes from the feature nodes located in the order of the feature nodes rearranged in order according to the distance between the feature line and the feature nodes. Here, the feature nodes are rearranged based on the similarity according to the distance to the feature line, and may be sorted in the order of similarity from high to low. In addition, the electronic device 101 may perform lossy compression through a filtering process in which feature nodes rearranged in order are removed according to the distance size.

The electronic device 101 may store lossy-compressed implicit terrain data in the database 102. The electronic device 101 may calculate the implicit surface of the implicit terrain data stored in the database 102 in consideration of the resolution of the implicit terrain data. Here, the electronic device 101 may visualize the implicit terrain data in a mesh form through a display capable of visualizing a digital image. In addition, the electronic device 101 may visualize the implicit topographic data by interworking with the receiving terminal 103 capable of visualizing the implicit surface.

2 is a flow chart illustrating a method of generating implicit terrain data according to an embodiment.

In step 201, the electronic device may read original terrain data generated from contour lines, aerial photographs, and satellite images. In addition, the electronic device may extract a node constituting the original terrain data. Here, nodes of the original terrain data may have different height values depending on their location. Also, the height value of the node may be one of 3D coordinates for expressing the 3D terrain. In addition, the height value of the node means a value expressed as an integer based on an error of resolution specified in the original terrain data, and may mean an altitude value according to the terrain.

The nodes of the original terrain data include only a three-dimensional coordinate value or simply a height value corresponding to the original terrain data, and this may include different values according to a method in which the electronic device 101 reads the original terrain data. As an example, nodes of the original terrain data are general coordinates to represent a 3D terrain, and may include 3D coordinates having a (x, y, h) shape. In addition, when the nodes of the original terrain data are arranged at equal intervals by a grid, since the (x, y) coordinates are implicitly known, only the height value (h) may be included.

In step 202, the electronic device may extract a feature line from the original terrain data. Specifically, the electronic device may extract feature lines of the original terrain data using a Profile recognition and polygon breaking algorithm (PPA). The PPA algorithm can find representative features by finding all the topographic irregularities by Profile-Recognition and removing minor features through the polygon-breaking process.

That is, the electronic device may extract feature points corresponding to the nodes of the original terrain data by using the PPA algorithm. In addition, the electronic device may extract a feature line indicating a medial axis by connecting nodes of the original terrain data corresponding to the extracted feature points.

In step 203, the electronic device may generate implicit terrain data from the original terrain data. The electronic device sets all the nodes constituting the original terrain data as feature nodes of the implicit terrain data, so that the feature nodes can include three-dimensional coordinates having the shape (x, y, h) like the nodes of the original terrain data. have.

In step 204, the electronic device may losslessly compress the generated implicit terrain data. Specifically, in step 205, the electronic device sets an initial feature node among the nodes of the implicit terrain data, and the number of initial feature nodes set according to a method of interpolating the implicit surface may vary. For example, the electronic device may automatically designate an initial feature node, and automatically set four nodes corresponding to four corners of the implied terrain data as the initial feature node. In addition, the electronic device may set the initial feature node in a matrix form according to a method of interpolating the implicit surface. That is, in order to losslessly compress the implicit terrain data, the electronic device may not extract the initial feature node through a separate method, but may set the initial feature node in different forms according to a method of interpolating the implicit surface.

The greedy algorithm can calculate the height value at all points by interpolating the implicit surface constructed from the set initial feature nodes and the added feature nodes. Thereafter, the greedy algorithm can repeat the process of comparing the height value of the node of the original terrain data with the height value of the implicit surface and adding the node with the largest difference as a feature node until the height error is within a tolerance. .

That is, the electronic device may perform lossless compression capable of extracting a minimum number of feature nodes to construct an implicit surface by interpolating the height values of all nodes of the original terrain data as they are.

)에 대한 높이값 데이터(

)들이 주어질 때 조건(

)을 만족하는 보간함수(s)에 의해 정의될 수 있다.In step 206, the electronic device may calculate the implicit surface of the implicit terrain data by interpolating the initial feature nodes and the feature nodes. Specifically, the implied surface of the implicit terrain data is coordinate data of the feature node included in the implicit terrain data (

Height value data for (

) When given conditions (

) Can be defined by the interpolation function (s).

가 될 수 있다. 이때, c는 높이값을 계산하고자 하는 임의 노드의 좌표값, ci는 특징 노드의 좌표값 일 수 있다. 이때

일 수 있다. 또한, 보간함수는 기초함수

의 합으로 계산될 수 있다. 이때, 기초함수는 임의 노드와 특징 노드간의 거리에 대한 함수일 수 있다. 기초함수는 다양한 형태가 가능하며, 대표적인 것으로 thin-plate spline RBF

과 Gaussian RBF

과 multi-quadric RBF

과 Bi-harmonic RBF

과 Wendland RBF

등이 있다. 이중에서 Gaussian RBF와 Wendland RBF에 대해서

인 경우에 Compactly-Supported RBF라 할 수 있다.There are various interpolation functions, but the softest form

Can be. In this case, c may be a coordinate value of an arbitrary node for which a height value is to be calculated, and ci may be a coordinate value of a feature node. At this time

Can be Also, the interpolation function is a basic function

It can be calculated as the sum of In this case, the basic function may be a function of a distance between an arbitrary node and a feature node. The basic function is available in various forms, and is a typical thin-plate spline RBF.

And Gaussian RBF

And multi-quadric RBF

And Bi-harmonic RBF

And Wendland RBF

Etc. Of these, Gaussian RBF and Wendland RBF

In the case of, it can be referred to as Compactly-Supported RBF.

와

조건을 사용하여 기초함수에 대한 가중치값

와 보간 정밀도를 높이는 보정치값

의 N+3개의 미지수에 대한 해를 구할 수 있다. 그리고, 이러한 과정을 정합(fitting)이라 할 수 있다. 보간함수는 묵시적 표면을 위한 보간함수가 결정되면 임의 노드의 좌표

에 대해서 높이값

을 결정(Evaluation)할 수 있다. 그런데, 묵시적 표면을 구성하는데 특징 노드가 추가되는 경우 보간함수에 주어지는 상기 조건들은 특징 노드가 추가됨에 따라 변하기 때문에 상기 가중치값과 보정치값들은 다시 계산해야 할 수 있다And, the interpolation function is given from the feature nodes constituting the implicit surface.

Wow

Weight value for basic function using condition

And correction value to increase interpolation precision

Solve for N+3 unknowns of. And, this process can be referred to as fitting. The interpolation function is the coordinates of an arbitrary node when the interpolation function for the implicit surface is determined.

About the height value

You can determine (Evaluation). However, when a feature node is added to construct an implicit surface, the conditions given to the interpolation function change as the feature node is added, so the weight value and correction value may need to be recalculated.

As a result, the electronic device may take a lot of time in the calculation process of matching the implicit surface and determining the height value. Here, the electronic device may use known Fast Multipole Method (FMM) or Partition of Unity Principle (PoU) methods to reduce calculation time. In addition, if the Compactly-Supported RBF is used, the calculation time can be shortened.

In step 207, the electronic device may determine the feature node using the node of the original terrain data and the initial feature node constituting the implicit surface. In detail, the electronic device compares the height values of the nodes constituting the original terrain data with the height values calculated from the implicit surfaces interpolating the initial feature nodes, and adds a feature node including the height value at the coordinates having the maximum error. I can. In addition, through this process, the electronic device may repeat until the height values calculated from the implicit surfaces interpolating the added feature nodes exactly match the height values of the nodes of the original terrain data. Here, the feature nodes may be stored in the order of a large contribution to the similarity between the node of the original terrain data and the node of the implicit terrain data.

The electronic device may generate an implied drawing representing a terrain similar to the original terrain data by introducing a concept of similarity between the original terrain data and the implied surface. As a result, the electronic device may perform lossless compression of the implicit surface generated according to the terrain of the implicit terrain data, having the greatest similarity to the original terrain data, that is, maintaining the same and minimal nodes.

In step 208, the electronic device may reconstruct losslessly compressed implicit terrain data. The electronic device may reconstruct a feature node according to an implicit model of losslessly compressed implicit terrain data according to a purpose. Specifically, feature nodes of the losslessly compressed implicit terrain data may be arranged according to their contribution to similarity to the original terrain. Here, the similarity between the implied topography and the original topography may be measured as a sum of squares of differences in height values or an average height value.

In this case, the similarity may not be arranged in a direction in which the similarity increases every time as feature nodes are added, or an imbalance may occur in increasing the similarity. In addition, overall, as feature nodes are added to the implicit terrain data, the similarity tends to increase continuously. However, in some cases, the similarity may decrease. In addition, as for the similarity, the rate of increase of the similarity is different for each region, so an imbalance in the similarity may be observed.

In consideration of the characteristics of the similarity, the electronic device may rearrange the feature nodes in a direction in which feature nodes of the implicit terrain data are generally and continuously increased. As a result, the electronic device may rearrange the feature nodes in a manner that changes the order when the distance between adjacent feature nodes is less than an allowable value in consideration of the regional distribution of feature nodes added to increase the overall similarity of the feature nodes.

Consequently, the electronic device rearranges the feature nodes in a manner that changes the order of the feature nodes according to the rearrangement method, so that the similarity to the feature nodes is not reduced, and an imbalance in the similarity can be prevented.

Looking at the location of the feature node added through the greedy algorithm, it can be initially formed mainly along the ridges and valleys of the original terrain. Feature nodes located in the ridge and valley may be located in the front or rear of the ridge and valley according to the magnitude of their contribution to the similarity. Specifically, a feature node located in a place where the original terrain is curved may be located in front of a ridgeline and a valley in order because the contribution to the similarity is large. Conversely, feature nodes located where the original terrain is not curved can be located behind the ridges and valleys in order because their contribution to similarity is small.

In addition, feature nodes may be rearranged in order to emphasize valleys and ridges, which are the main features of the original terrain. To this end, the electronic device may extract feature lines representing valleys and ridges from the original terrain through the PPA algorithm. In addition, the electronic device may calculate the distance between the extracted feature lines and feature nodes, and rearrange them in order as the distance difference decreases, that is, as the feature nodes are closer to the feature lines. Conversely, the electronic device may calculate the distance between the extracted feature lines and feature nodes, and rearrange them in order as the distance difference increases.

In step 209, the electronic device may detail the reconstructed implicit terrain data. The electronic device may group feature nodes to designate a detail view. In general, when the terrain data is visualized at a high altitude, it is difficult to determine the detailed shape of the terrain, and it may be possible to observe mainly valleys and ridges, which are the main features of the terrain.

Accordingly, the electronic device may perform restoration of the original terrain using only the feature nodes of the implied terrain data without needing to restore the terrain data by reflecting 100% of the original terrain with respect to the terrain data.

That is, the electronic device may restore implicit terrain data using only feature nodes according to similarity proportional to the altitude at which the terrain is observed. To this end, the electronic device may adjust and map the similarity value calculated up to the corresponding node to all the feature nodes and feature nodes in the rearranged order through the process of measuring the similarity to a value between '0' and '1'. .

In this case, the similarity value is designated for every feature node because the data size becomes too large when the terrain is restored through the similarity value of the node of the original terrain data. As an example, the electronic device may assume that the node spacing of the original terrain data is 10m. In addition, the implicit terrain data losslessly compressed and reconstructed based on the original terrain data may generate a terrain model by interpolating height values at various node intervals such as 0.1, 1, 2, 5m from the implicit surface.

In this case, the terrain model has a high altitude for observing the terrain in the process of generating the terrain model, and thus the terrain model may be interpolated with a height value higher than the spacing of nodes of the original terrain data. In this case, in the terrain model, interpolation of the terrain model is incorrect, and detailed information included in the original terrain model may be lost.

Accordingly, the electronic device may restore the terrain model using a feature node for a detailed view of a lower level than the original terrain so that the original terrain can be restored without losing detailed information about the terrain. That is, in the electronic device, the amount of calculation required for terrain restoration may increase as the area of the terrain to be visualized increases as the altitude at which the terrain is observed increases. Accordingly, the electronic device may reduce the number of feature nodes and the amount of calculation used for terrain restoration by lowering the similarity to the unit of the terrain model in proportion to an increase in the amount of calculation as the visualization area increases. Consequently, as the electronic device reduces the amount of calculation according to the terrain reconstruction, the overall amount of calculation required for the restoration of the terrain model can be kept constant.

To this end, the electronic device may divide the entire similarity into several stages according to the similarity value, and record only the position of the feature node at the beginning of each divided stage, thereby grouping the feature nodes and designating a detailed degree. As an example, the electronic device may designate a detailed view by grouping the feature node and the nodes corresponding to the feature node into four stages, divided into 0.0 to 0.25, 0.25 to 0.5, 0.5 to 0.75, and 0.75 to 1.0 according to the similarity value. .

In step 210, the electronic device may lossy compress the reconstructed implicit terrain data. The electronic device may filter feature nodes constituting the reconstructed implicit terrain data. Specifically, lossless compression and reconstructed implicit terrain data may restore the original terrain as it is using the initial feature node and the gong node. Implicit terrain data is a method of removing some of the feature nodes located behind the sequence of the array from the losslessly compressed implicit terrain data, reducing the size of the data, but maintaining the overall terrain similar to the original terrain.

That is, the electronic device may perform lossy compression more easily by removing the feature nodes one by one from the back of the order when the order of the feature nodes is rearranged in a direction in which the overall degree of similarity continuously decreases.

As a result, the electronic device can provide the data having a large amount of data to the user without a significant deterioration in quality of the terrain represented by the original terrain data by performing minimal lossy compression on nodes based on similarity.

In step 211, the electronic device may calculate an implicit surface by using a node of implicit terrain data stored in the database. In addition, the electronic device may convert the implicit surface into a mesh form and visualize it through the display.

Specifically, the electronic device may visualize in the form of a mesh by interconnecting neighboring vertices using a height value sampled at equal intervals on the implicit surface as a vertex.

In addition, the electronic device may divide and transmit the nodes of the implicit terrain data in order to a receiving terminal capable of visualizing the implicit surface. In addition, the receiving terminal may receive nodes of the implicit terrain data dividedly according to an order, and may configure a terrain based on initial feature nodes of the implicit terrain data according to the received order. Thereafter, the receiving terminal may gradually visualize the implicit terrain data while increasing similarity to the implicit terrain data by adding additionally received feature information to the configured terrain.

The electronic device and the receiving device are means for visualizing implicit terrain data, and may perform a role of navigation of movable objects such as vehicles, ships, and airplanes.

3 is a diagram illustrating feature lines and feature nodes of implicit terrain data according to an embodiment.

Referring to FIG. 3, the electronic device may visualize feature lines representing ridgelines and valleys extracted from original terrain data, and initial feature nodes and feature nodes constituting the implicit surface of the implied terrain data.

In other words, the original terrain data may express a height value according to the brightness of a color for each node in a rectangular terrain, and a higher altitude may be indicated as the color saturation increases. In addition, the feature line may be extracted through the PPA algorithm to represent a ridge line or a valley. In addition, the initial feature nodes and feature nodes of the implied surface generated from the original terrain data are indicated by white dots, and may be distributed similarly to the feature lines of the original terrain data. As an example, the implied terrain data may mean the height of each node in the order of black to white. In addition, a part represented by a line may represent a feature line of the implied terrain data, and a part represented by a white dot may represent a feature node of the implied terrain data.

In this case, the electronic device may sequentially receive initial feature nodes and feature nodes arranged according to the detail view from the database, gradually increase the similarity according to the detail view, and visualize the implicit terrain data.

4 is a diagram illustrating implicit terrain data according to another embodiment.

Referring to FIG. 4, the electronic device may report implicit terrain data as a 3D terrain. In other words, the electronic device may designate height values sampled at equal intervals with respect to the implicit surface based on the implicit terrain data as vertices. In addition, the electronic device may interconnect the designated vertices and neighboring vertices to transform them into a mesh form, and visualize them through a rendering process.

Electronic devices can be used in navigation systems for movable objects such as vehicles, ships, and airplanes.

The apparatus described above may be implemented as a hardware component, a software component, and/or a combination of a hardware component and a software component. For example, the devices and components described in the embodiments include, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA), It can be implemented using one or more general purpose computers or special purpose computers, such as a programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications executed on the operating system. In addition, the processing device may access, store, manipulate, process, and generate data in response to the execution of software. For the convenience of understanding, although it is sometimes described that one processing device is used, one of ordinary skill in the art, the processing device is a plurality of processing elements and/or a plurality of types of processing elements. It can be seen that it may include. For example, the processing device may include a plurality of processors or one processor and one controller. In addition, other processing configurations are possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of these, configuring the processing unit to behave as desired or processed independently or collectively. You can command the device. Software and/or data may be interpreted by a processing device or to provide instructions or data to a processing device, of any type of machine, component, physical device, virtual equipment, computer storage medium or device. , Or may be permanently or temporarily embodyed in a transmitted signal wave. The software may be distributed over networked computer systems and stored or executed in a distributed manner. Software and data may be stored on one or more computer-readable recording media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the embodiment, or may be known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. -A hardware device specially configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of the program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operation of the embodiment, and vice versa.

As described above, although the embodiments have been described by the limited embodiments and drawings, various modifications and variations are possible from the above description by those of ordinary skill in the art. For example, the described techniques are performed in a different order from the described method, and/or components such as a system, structure, device, circuit, etc. described are combined or combined in a form different from the described method, or other components Alternatively, even if substituted or substituted by an equivalent, an appropriate result can be achieved. Therefore, other implementations, other embodiments, and claims and equivalents fall within the scope of the claims to be described later.

101: electronic device
102: database
103: receiving device

Claims (20)

Constructing implicit terrain data from original terrain data;
Lossless compressing the implicit terrain data;
Reconstructing the losslessly compressed implicit terrain data;
Detailing the reconstructed implicit terrain data; And
Lossy compressing the reconstructed implicit terrain data;
Including,
The subdividing step,
A method of generating implicit terrain data for grouping and subdividing the feature nodes of the implied terrain data into a plurality of steps to restore the implied terrain data using a feature node of the implied terrain data according to a similarity proportional to the altitude at which the terrain is observed. The method of claim 1,
The configuring step,
A method of generating implicit terrain data for constructing implicit terrain data using a height value for a node constituting the original terrain data. The method of claim 1,
The step of lossless compression is
Extracting initial feature nodes from the nodes of the implicit terrain data;
Generating an implicit surface of implicit terrain data by interpolating the initial feature nodes; And
Adding feature nodes using the original terrain data and the calculated implicit surface;
Implicit terrain data generation method comprising a. The method of claim 3,
The initial feature nodes are nodes initially set in implicit terrain data according to an interpolation method for generating an implicit surface,
The feature nodes are nodes that are added in consideration of a preset tolerance according to a comparison between a height value of a node of the original terrain data and a height value of an implicit surface. The method of claim 3,
The implied surface,
An initial feature node representing a preset height value and a method of generating implicit terrain data including a height value of an arbitrary point through interpolation between the initial feature nodes. The method of claim 3,
The step of adding
A feature node having a height value of the original terrain data when the height value of the implicit surface is large by comparing the height value of the nodes constituting the original terrain data with the height value of the implicit surface calculated by interpolating the initial feature nodes. How to create implicit terrain data to add. The method of claim 3,
The reconstructing step,
Reconstructing losslessly compressed implicit terrain data through rearrangement of the order of the added feature nodes using a feature line indicating a central axis to which feature points are connected in the original terrain data,
The feature line,
The method of generating implicit terrain data by analyzing the original terrain data and connecting feature points constituting a valley and a ridge line. The method of claim 7,
The rearrangement is,
An implicit terrain data generation method for rearranging the order of feature nodes in proportion to the distance between the feature line and the added feature node. The method of claim 1,
The step of lossy compression,
A method of generating implicit terrain data in which the size of implicit terrain data is reduced by sequentially removing feature nodes from the order of the rearranged feature nodes in the reconstructed implicit terrain data. The method of claim 1,
And converting the loss-compressed implicit terrain data into a mesh form and visualizing the implicit terrain data. The method of claim 10,
The visualizing step,
A method of generating implicit terrain data for calculating the implicit terrain data, extracting a height value of each node according to a resolution, generating a mesh by interconnecting 3D coordinates of each node, and mapping a texture to the generated mesh to visualize it. In the electronic device for generating implicit terrain data,
The electronic device includes a processor, and the processor
Generating implicit terrain data using height values for nodes constituting the original terrain data;
Lossless compression using nodes of the implicit terrain data;
Reconstructing the losslessly compressed implicit terrain data;
Detailing the reconstructed implicit terrain data; And
Lossly compressing the reconstructed implicit terrain data using the original terrain data and the implicit terrain data;
And
The subdividing step,
An electronic device for grouping and subdividing feature nodes of the implied terrain data into a plurality of steps so as to restore the implied terrain data using a feature node of the implied terrain data according to a degree of similarity proportional to the altitude at which the terrain is observed. The method of claim 12,
The step of lossless compression is
Extracting initial feature nodes from the implicit terrain data;
Generating an implicit surface of implicit terrain data by interpolating the initial feature nodes; And
Adding feature nodes using the original terrain data and the calculated implicit surface;
Electronic device comprising a. The method of claim 13,
The implied surface,
An electronic device including an initial feature node representing a preset height value and a height value of an arbitrary point through interpolation between the initial feature nodes. The method of claim 13,
The step of adding
A feature node having a height value of the original terrain data when the height value of the implicit surface is large by comparing the height value of the nodes constituting the original terrain data with the height value of the implicit surface calculated by interpolating the initial feature nodes. Electronic device to add. The method of claim 13,
The reconstructing step,
Reconstructing losslessly compressed implicit terrain data through rearrangement of the order of the added feature nodes using a feature line indicating a central axis to which feature points are connected in the original terrain data,
The feature line,
An electronic device that is generated by analyzing the original terrain data and connecting feature points constituting a valley and a ridge. The method of claim 16,
The rearrangement is,
An electronic device that rearranges the order of feature nodes in proportion to the distance between the feature line and the added feature node. The method of claim 12,
The step of lossy compression is
An electronic device for reducing the size of implicit terrain data by sequentially removing feature nodes from a lower order in the order of the rearranged feature nodes from the reconstructed implicit terrain data. The method of claim 12,
The electronic device further comprising the step of converting the loss-compressed implicit terrain data into a mesh form and visualizing the data. The method of claim 19,
The visualizing step,
An electronic device that calculates the implicit terrain data, extracts a height value of each node according to a resolution, generates a mesh by interconnecting 3D coordinates of each node, and then maps and visualizes a texture on the generated mesh.

Images