JP2013054499A - Forest stereoscopic image generation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forest stereoscopic image generation method that gives stereoscopic effects to respective trees of a forest and enables states under a surface layer to be grasped at a glance without using any plane color photograph.SOLUTION: A forest stereoscopic image generation device includes a database 10 which stores DEM data, a database 11 which stores DSM data, a DHM data generation section 12, a DSM red stereoscopic image generation section 14, a gray-scale imaging section 16, a greenish color imaging section 18, a multiplication section 23, etc., and generates an image (tree height section figure) in which colors corresponding to tree heights of trees are allocated to the trees, the image being named a forest place stereoscopic image which is made stereoscopic.

Description

  The present invention relates to a forest land stereoscopic image generation method.

  Orthophoto images have been used in various systems in recent years because of their high visual appeal.

  For example, Patent Document 1 discloses that a vertex of a tree is obtained by using DEM (Digital Elevation Model) and DSM (Digital Surface Model) and the vertex is displayed on the tree of the orthophoto image.

JP 2008-1111724 A

  The orthophoto image is a planar color photographic image obtained by geometrically converting a photograph of the surface layer taken by an aircraft into an orthographic projection. Therefore, it is possible to easily determine visually differences between trees, buildings, roads, ground, grassland, and the like.

  However, in the orthophoto image, a shadow due to topography or a feature occurs due to the relationship with the solar altitude at the time of photographing, or a misalignment of a joint portion of a plurality of photographs occurs, so that an invisible portion may occur. In addition, there is a difference in color tone due to bonding, which may cause poor appearance.

In addition, misalignment of the feature causes misplacement or invisible places, especially when trees grow in small valleys in mountainous areas, making it difficult to interpret because of the flat color photograph. .

  On the other hand, most of the trees have similar colors (for example, green), so even in the ridges, it is not easy to judge the tree species and tree height, and when using orthophoto images, the mountain area lacks stereoscopic effect, It is not possible to easily grasp the topographical conditions under the surface layer.

  The present invention has been made in order to solve the above problems, and without using a two-dimensional color photograph, a three-dimensional tree height map in which each tree in the forest has a three-dimensional effect, and the topographical conditions under the surface layer are also at a glance. The purpose is to obtain a method for generating a 3D forest land image that can be grasped by.

The forest land three-dimensional image generation method of the present invention,
Computer
Storing a predetermined range of DEM data in the first storage means;
Storing the predetermined range of DSM data in a second storage means;
Based on a predetermined plant height, a color value that is darker as the plant height is higher is assigned, and a color value that is lighter as the plant height is lower than the predetermined plant height is assigned. Storing the obtained color conversion table;
Generating a difference image between the DEM data of the first storage means and the DSM data of the second storage means as DHM data;
The z-value of each grid of the DHM data is read, the z-value is compared with the color conversion table, and the color value based on the color conversion table is assigned to the grid of the DHM data to thereby match the plant height according to the plant height. Generating color segmented image data;
Each grid of the DSM data of the first storage means is a point of interest, and a certain range is defined for each point of interest to determine the ground opening, the underground opening, and the slope. Generating DSM red stereoscopic image data in which a dark color is assigned each time the underground opening is large, and a color in which red is emphasized as the slope is large, respectively.
Generating DSM stereoscopic gray image data obtained by graying out the DSM red stereoscopic image data;
The step of multiplying the DSM stereoscopic gray image data and the plant high-color segmented image data to generate forest land stereoscopic image data that allows each of the plant crowns to be stereoscopically viewed with a color corresponding to the plant height is performed. And

Moreover, the forest land three-dimensional image generation method of the present invention includes:
Computer
Storing a predetermined range of DEM data in the first storage means;
Storing the predetermined range of DSM data in a second storage means;
Based on a predetermined plant height, a color value that is darker as the plant height is higher is assigned, and a color value that is lighter as the plant height is lower than the predetermined plant height is assigned. Storing the obtained color conversion table;
Generating a difference image between the DEM data of the first storage means and the DSM data of the second storage means as DHM data;
The z-value of each grid of the DHM data is read, the z-value is compared with the color conversion table, and the color value based on the color conversion table is assigned to the grid of the DHM data to thereby match the plant height according to the plant height. Generating color segmented image data;
Each grid of the DEM data of the second storage means is a point of interest, and a certain range is defined for each point of interest to determine the ground opening, the underground opening, and the slope. Generating DEM red stereoscopic image data in which a dark color is assigned each time the underground opening is large, and a color in which red is emphasized as the slope is large, respectively.
Generating DEM yellowed red stereoscopic image data obtained by converting the DEM red stereoscopic image data to yellow;
Defining each grid of the DHM data as a point of interest, defining a certain range for each point of interest, obtaining a ground opening, and generating DHM ground opening image data in which the ground opening is assigned to each grid; ,
The gist of the present invention is to generate a forest land stereoscopic image obtained by synthesizing the DEM red stereoscopic image data, DEM yellowed red stereoscopic image data, and DHM ground opening image data.

  As described above, according to the present invention, there is provided a forest land three-dimensional image that allows each tree in the forest to have a three-dimensional feeling and can also grasp the topographic condition of the surface layer at a glance without using a planar color photograph. Can be obtained.

It is a schematic block diagram of the forest land three-dimensional image creation apparatus of this Embodiment 1. It is explanatory drawing of a RGB conversion table. It is explanatory drawing of a RGB conversion table. It is explanatory drawing of a DSM red three-dimensional image. It is explanatory drawing of the grayed-out DSM red three-dimensional image. It is explanatory drawing explaining a green color image. It is explanatory drawing explaining a forest land three-dimensional image. It is explanatory drawing explaining the DSM red three-dimensional image (A) at the time of using the RGB table 20a. It is explanatory drawing explaining the grayed-out DSM red three-dimensional image (I) at the time of using the RGB table 20a. It is explanatory drawing explaining the image (c) which allocated the green system to the DHM image at the time of using the RGB table 20a. It is explanatory drawing explaining the image of the multiplication result of (a) and (c). It is a schematic block diagram of the forest land three-dimensional image creation apparatus of this Embodiment 2. It is a flowchart explaining the operation | movement of this Embodiment 2. FIG. It is explanatory drawing of a ground opening degree and an underground opening degree. It is explanatory drawing explaining the comparison with an ortho image and a DHM ground opening image. It is explanatory drawing explaining the comparison of an orthophoto image and a red three-dimensional image. It is explanatory drawing of a DEM yellowish red three-dimensional image. It is explanatory drawing explaining the comparison of an orthophoto image and the forest land three-dimensional image of this Embodiment 2. FIG.

  The following embodiment exemplifies an apparatus and method for embodying the technical idea of the present invention, and the technical idea of the present invention is the material, shape, structure, and arrangement of components. Etc. are not specified as follows. The technical idea of the present invention can be variously modified within the technical scope described in the claims. It should be noted that the drawings are schematic and the configuration of the apparatus and system is different from the actual one.

  In the present embodiment, a color image is assumed to be an orthophoto image, and an image obtained by photographing a mountain portion with an aircraft will be described.

  The forest land stereoscopic image generation apparatus according to Embodiment 1 creates an image (also referred to as a tree height division diagram) in which a color corresponding to a tree height of a tree (including grass) is assigned to the tree, and this is stereoscopically generated. Show (referred to as forest land stereoscopic image). The colors assigned to the trees are assigned according to the vegetation situation in the area. For example, a dark green color is preferable for a tall tree or an old forest, and a bright green color is preferable for a sub-tree or a young forest.

  It is also possible to assign green colors in spring and summer, brown colors in autumn, and vermilion colors (however, conifers are green).

  The outline of the method of generating the forest land stereoscopic image is to create DHM from the difference between DEM and DSM generated based on the laser data obtained by the aircraft. Then, a tree-level chart is created by associating this DHM with a color table of deep green-green-light green-white.

  Furthermore, in order to give this a three-dimensional effect, a gray scale image of the DSM red three-dimensional map is synthesized.

In other words, the three-dimensional map of the tree height does not represent the ground below the forest, but the red three-dimensional map of DSM is grayscaled and expressed by a green high-level color scheme.

The color table to be used is a color that takes into account regional vegetation and seasons. At first glance, it is similar to orthophoto, but it is easy to understand because it reflects the structure of the height of the forest and the state of the forest canopy. For example, a lawn that does not have a height as a tree turns gray. The slope that is the shadow of the sun can also be expressed in an easy-to-understand manner. Similarly, since there is an advantage that there is no cloud shadow, it can be used for vegetation interpretation and the like.

  In addition, when reflecting the terrain, the red three-dimensional map of the DEM is synthesized with lower saturation and contrast (described in Embodiment 2).

<Embodiment 1>
FIG. 1 is a schematic configuration diagram of a forest land stereoscopic image creation apparatus according to the first embodiment (also referred to as a tree height division stereoscopic image creation apparatus).

  In the present embodiment, a description will be given of generation of a forest land stereoscopic image of a summer forest area (including grassland and roads).

  As shown in FIG. 1, a database 10 storing DEM, a database 11 storing DSM, a DHM data generating unit 12 for generating DHM data, a memory 13 for storing DHM data, and a DSM (surface layer model) A DSM red three-dimensional image creation unit 14 that converts data into a red three-dimensional image, a memory 15 that stores the DSM red three-dimensional image, and a grayscale imaging unit that converts the DSM red three-dimensional image into a gray image (also referred to as a grayscale image). 16, a memory 17 (also referred to as a DSM red grayscale image) in which a grayscale image is stored, and a green color image converting unit that converts the DHM image into a green color image based on the RGB conversion table 20 i of a specified region 18, the memory 19 in which the green color image is stored, and the DSM red grayscale image and the green color image are multiplied. A multiplication unit 23, the tree height divided image of a multiplication result to the memory 24 to be stored, a controller unit 25 for controlling each, a display unit 26 or the like.

  Furthermore, a database 28 storing a map to which latitude and longitude are assigned, and a map display processing unit 29 are provided. The map display processing unit 29 displays a map of the database 28 on the display unit 26 and displays a map of an area selected by a mouse or a keyboard (not shown) on the screen.

  The above-mentioned DEM (Digital Elevation Model) is ground data obtained by removing buildings and trees, etc., obtained by aircraft laser measurement, and creates contour maps that connect the same elevation values of each laser data. A TIN is created from this contour map to restore the ground, and the height of the point where TIN and each grid point intersect is obtained.

  That is, it has a DEM data mesh structure (0.2 m, 0.5 m, etc.), covers the target range with a grid, and assigns the elevation value of the feature for each grid point.

  The DSM (Digital Surface Model) is obtained by laser measurement using an aircraft and automatic matching technology using stereo photography.

  The DSM has a mesh structure (0.2 m, 0.5 m, etc.), which covers the object range with a grid and indicates the altitude value of the feature assigned to each grid point.

  That is, in DEM and DSM, the minimum unit is a pixel (small square: x, y), and a height z is assigned to each pixel.

  The DHM data creation unit 12 reads the DSM corresponding to the region currently displayed by the map display unit 29 from the database 10 and also reads the DSM of the same region stored in the DEM and the database 11 and stores the difference data of both. It is generated and stored in the memory 13 as DHM data.

  The DSM red three-dimensional image creation unit 14 reads the DSM in the database 11, obtains three parameters of inclination, ground opening, and underground opening based on this DSM, sets the plane distribution as a grayscale image, The difference image of the underground opening is put in gray, the slope is put in the red channel, and a pseudo color image (red three-dimensional image) is created and stored in the memory 15. In other words, the ridges and mountain peaks are whitish, the valleys and depressions are dark, and the steeper parts are red. As a result, a stereoscopic effect can be obtained even with a single image.

  The gray scale imaging unit 16 converts the red three-dimensional image in the memory 15 into a gray scale image, and stores this in the memory 17 as a DSM red gray scale image.

  The green colorizing unit 18 assigns an RGB table 20i (20a, 20b,..., 20j) corresponding to an area (for example, A area or B area of Mt. Fuji) input by operating a keyboard or a mouse. Then, the altitude value z of each mesh data of the DHM image in the memory 13 is read, and a green color image in which green RGB values corresponding to the z value are assigned to the mesh is stored in the memory 19.

  The multiplication unit 23 stores an image obtained by multiplying the green color image in the memory 19 and the gray scale image in the memory 17 in the memory 24 as an altitude value division image (also referred to as a forest land stereoscopic image).

  The controller unit 25 controls the database 10, the database 11, and the data in each memory to be output to each corresponding unit and displays the image data in the memory on the display unit 26.

  The DHM data creation unit 12, the red stereoscopic image creation unit 14, the gray scale imaging unit 16, the green color imaging unit 18, the multiplication unit 23, and the controller unit 25 are programs stored in the ROM and stored in the RAM. Stored and executed by the CPU.

  The RGB conversion table will be described. The RGB conversion table 20i is provided for each region.

  FIG. 2 is an explanatory diagram of an RGB conversion table used as a coloring in an area where many artificial forests with a tree height of around 20 m are distributed in the foothill area of Mount Fuji, where RGB values correspond to tree height values.

For example, as shown in FIG.
(1) When the tree height value is 0 m to 2.99 m, “255” is assigned as the R, G, and B values.

(2) In the tree height values 3 m to 4.99 m, the R value is “165”, the G value is “149”, and the B value is “5”.

(3) In the tree height values of 5 m to 9.99 m, the R value is “185”, the G value is “217”, and the B value is “2”. See FIG. 2 below.

  FIG. 2 (b) shows the actual colors of FIG. 2 (a). In FIG. 2B, white is assigned at an altitude of 0 m to 2.99 m, and a color close to orange is assigned at 3 m to 4.99 m, and deep green (the darkest green) is assigned at 18 m or more.

  FIG. 3 is an explanatory diagram of an RGB conversion table used for coloring a wasteland where hillside construction has been performed in the Ashio area of the Watarase River, where RGB values are associated with tree height values.

For example, as shown in FIG.
(1) When the tree height value is 0 m to 2.99 m, “255” is assigned as the R, G, and B values.

(2) In the tree height values 3 m to 4.99 m, the R value is “250”, the G value is “230”, and the B value is “44”.

(3) In the tree height values 5 m to 9.99 m, the R value is “211”, the G value is “249”, and the B value is “0”. See FIG. 3 below.

  FIG. 3 (b) shows the actual colors of FIG. 3 (a). In FIG. 3 (b), it is white at an altitude of 0 m to 2.99 m, a slightly dark yellow-green color is assigned at 3 m to 4.99 m, green is assigned at 18 m to 19.9 m, and the darkest green at 20 m or more. Assigned.

  That is, according to the height of the tree existing in the area, the color table is white → light green → green → deep green as the tree height value increases.

  In creating this table, we conducted a local vegetation survey to determine an appropriate color value according to the height of the tree.

(Detailed explanation)
In the first embodiment, a description will be given on the assumption that the memory 13 stores DHM (only building and tree data) that is the difference between the DSM and the DEM.

  The DSM red three-dimensional image creation unit 14 reads the DSM of the designated area from the database 11, sets each mesh (also referred to as a pixel or a pixel) as a point of interest, and sets a certain range (for example, 1 m) from this point of interest. ) 8 directions above the ground opening, underground opening and slope, the brighter the color the greater the ground opening, the darker the color the greater the underground opening, the red the greater the slope The DSM red three-dimensional images assigned with the respective colors are generated and stored in the memory 15 (see FIG. 4).

  Then, the gray scale imaging unit 16 converts the DSM red stereoscopic image based on the DSM in the memory 15 into a black and white image and stores it in the memory 17 (see FIG. 5).

  Thus, even if the DSM red stereoscopic image is converted into black and white, the red stereoscopic image is expressed in black as the height is low, and red in the steep portion. (See FIG. 5).

  On the other hand, the green colorization unit 18 reads the DHM data in the memory 13 and assigns the RGB conversion table 20b corresponding to the designated area (in the present embodiment, the upstream Ashio area of Watarase River). In the present embodiment, the RGB conversion table 20b is the Watarase River upstream Ashio area.

  Then, for each DHM mesh, the green colorizing unit 18 reads the tree height assigned to the mesh, and reads the RGB value corresponding to the tree height from the RGB conversion table 20b. Then, by assigning the read RGB values to each mesh, a green color image shown in FIG. 6 is obtained.

As shown in FIG. 6, in the green color image, the higher the tree, the darker the green, and the lower tree (lawn), the whitish.
Then, the multiplication unit 23 multiplies the grayscale image (FIG. 5) in the memory 17 and the green-colored image (FIG. 6) in the memory 19 to assign the three-dimensional tree height division image (latitude and longitude assigned) shown in FIG. It is also called a forest land 3D map.

  That is, since the DSM red grayscale image is a gray of the red three-dimensional image, there is a stereoscopic effect even in black and white. Since this image is overlaid with an image assigned a green color according to the vegetation height of the area (including trees, grassland, roads, and mountains), it is a flat color image as shown in FIG. Regardless, the ridges, valleys, etc. are three-dimensional.

  That is, the forest land three-dimensional map is more three-dimensional because it assigns a color according to the height of the vegetation (plant) at the time of obtaining the aerial laser measurement data and emphasizes the height.

  In addition, the unevenness of the ground is also emphasized, so the distribution of trees is three-dimensional.

  The images when the RGB table 20a is used are shown in FIG. 8, FIG. 9, FIG. 10, and FIG. FIG. 8 shows a DSM red stereoscopic image (A) when the RGB table 20a is used, FIG. 9 shows a grayed DSM red stereoscopic image (A) when the RGB table 20a is used, and FIG. 10 shows a DHM image. Fig. 11 shows an image (c) in which green is assigned, and Fig. 11 shows an image obtained by multiplying (a) and (c).

  If the method according to the present embodiment is used even in a wide area, a color corresponding to the height of the tree is assigned, and a three-dimensional image showing the ground condition is obtained.

<Embodiment 2>
In the second embodiment, the ground below the forest is also expressed, and the red three-dimensional map of the DEM is used in yellow.

  FIG. 12 is a schematic configuration diagram of the forest land stereoscopic image creation apparatus according to the second embodiment. In the figure, the same reference numerals as those in the first embodiment are omitted. FIG. 13 is a flowchart for explaining the operation of the second embodiment.

  The color image stereoscopic visualization apparatus according to the second embodiment stores a DEM red stereoscopic image creation unit 30 that generates a red stereoscopic image (referred to as a DEM red stereoscopic image) using the DEM of the database 10 and a DEM red stereoscopic image. A memory 31, a color tone changing unit 32 that obtains a DEM yellowish red three-dimensional image obtained by yellowing the DEM red stereoscopic image in the memory 31, a memory 33 in which the DEM yellowish red stereoscopic image is stored, and a DHM in the memory 13 The ground opening degree calculation unit 36 for obtaining the ground opening degree data (DHM ground opening degree data), the memory 37 in which the ground opening degree data is stored, the green color image in the memory 19 and the DHM ground opening degree data in the memory 37 Are combined with a synthesizing unit 34 for obtaining a three-dimensional forest land image, a memory 35 for storing the three-dimensional forest image, and the like.

  The DEM red three-dimensional image creation unit 30 obtains the ground opening data and the underground opening data for each mesh of the DEM in the database 10 in an area included in a range up to a certain distance (50 m), and calculates the difference between the two. A DEM red three-dimensional image in which the color is made gray and the deeper the inclination is, the red DEM red three-dimensional image is generated and stored in the memory 31.

  The color tone changing unit 32 applies a yellow color tone to each mesh of the DEM red three-dimensional image in the memory 31. The color is assigned to the yellow color by the operator using Photoshop to find a color that becomes ocher while looking at the hue and entering a numerical value in a setting called color balance. This set value numerical value is stored in a memory (not shown) corresponding to the area of the image, and thereafter, when this area is input, the numerical value to be yellowed is read from the memory and the DEM red stereoscopic image is yellowed. It is preferable to do so.

  The ground opening calculation unit 36 generates and averages terrain sections for each of the eight directions in a region included in a range up to a certain distance (5 m) for each DHM mesh (also referred to as a point of interest) in the database 13. Obtain ground opening data.

The synthesizing unit 34 synthesizes the green-colored image in the memory 19, the DEM ground opening data in the memory 37, and the DEM yellowish red three-dimensional image stored in the memory 33 (S12), and uses this as a forest land three-dimensional image. Store in the memory 35.

  In the embodiment, each memory and a controller unit for controlling each unit are provided, but the description is omitted in the embodiment.

  The DEM red stereoscopic image creating unit 30, the color tone changing unit 32, the ground opening degree calculating unit 36, the synthesizing unit 34, and the like described above are programs stored in the ROM, stored in the RAM, and executed by the CPU.

(Description of operation)
The DHM data creation unit 12 reads the DSM corresponding to the region currently displayed by the map display unit 29 from the database 10 (S1), and reads the DEM of the same region stored in the database 11 (S2).

  Then, both difference data are generated (S3) and stored in the memory 13 as DHM data (S4).

  Next, the green colorization unit 18 reads the DHM data in the memory 13, assigns the RGB conversion table 20i corresponding to the designated area, reads the tree height assigned to the mesh for each DHM mesh, The RGB value corresponding to the tree height is read from the RGB conversion table 20i. Then, by assigning the read RGB values to each mesh, a green-based green color image (also referred to as a tree height stage chart) corresponding to the tree height is obtained (S5: refer to FIG. 6) and stored in the memory 19. (S6). In this green color image, the higher the trees, the darker the green, and the lower trees (lawn, grassland) are transparent.

  On the other hand, the ground opening calculation unit 36 generates a topographic cross section for each of the eight directions in a region included in a range up to a certain distance (5 m) for each DHM mesh (also referred to as a point of interest) in the database 13. The maximum value (when viewed from the vertical direction) of the line connecting the point and the point of interest (L1 in FIG. 14A) is obtained. Data obtained by performing such processing for eight directions and averaging the data is the ground opening data (average angle when viewing the range of L from the point of interest in the eight directions: an index for determining whether it is high) For each mesh and stored in the memory 37 as DHM ground opening data (S8). The angle of inclination is the angle from the zenith (90 degrees for flats, 90 degrees or more for ridges and peaks, and 90 degrees or less for valleys and depressions).

  In addition, the ground opening increases as the point protrudes from the surroundings, and takes a large value at the summit or ridge and is small at the valley or depression.

  For example, FIG. 15 shows an image in which a gray scale is assigned according to the opening degree of the ground opening degree data. In FIG. 15, (a) shows an ortho image, and (b) shows the DHM ground opening degree assigned with a gray scale.

  On the other hand, the DEM red three-dimensional image creation unit 30 obtains the ground opening data and the underground opening data for each mesh of the DEM in the database 10 in an area included in a range up to a certain distance (50 m). By creating a pseudo color image with the difference between the gray and the slope in the red channel, the roots and peaks are whitish, the valleys and depressions are dark, and the steep slopes are red. With such a combination of expressions, at least one image with a three-dimensional effect (red three-dimensional image: see FIG. 16) is generated and stored in the memory 31 (S9). FIG. 16A shows an orthophoto image, and FIG. 16B shows a red three-dimensional image.

  The above-mentioned underground opening degree data is the inverted DEM data (FIG. 14 (c)) in which a solid (FIG. 14 (b)) is turned upside down on a certain range of DEM data (ground surface: solid). The angle formed by the straight line L2 connecting the point C (corresponding to the deepest point) that becomes the maximum vertex when any one of the eight directions is viewed from the point A is determined. Obtaining and averaging this angle over eight directions is called the underground opening.

  Next, the color tone changing unit 32 assigns yellow to the DEM red three-dimensional image in the memory 31 and changes it to an orange image (S10: FIG. 17). And this is memorize | stored in the memory 33 as a DEM yellowish red three-dimensional image (S11).

  The synthesizing unit 19 synthesizes the green-colored image in the memory 19, the DEM ground opening data in the memory 37, and the DEM yellowish red three-dimensional image stored in the memory 33 (S12). The image is stored in the memory 35 (S13: see FIG. 18).

  FIG. 18A shows an orthophoto image of the same region, and FIG. 18B shows a forest land stereoscopic image of the second embodiment. As shown in FIG. 18B, since the unevenness of the ground is more emphasized, valleys, depressions and ridges under the forest can be seen with a three-dimensional effect. In addition, since the forest is emphasized in green by the area unevenness and tree height, the three-dimensional effect is more emphasized.

  Therefore, compared with the orthophoto image shown in FIG. 18A, the forest land stereoscopic image of the second embodiment has a stereoscopic effect.

12 DHM data creation unit 14 DSM red stereoscopic image creation unit 16 Gray scale imaging unit 18 Green color imaging unit 23 Multiplying unit 30 DEM red stereoscopic image creation unit 32 Color tone change unit 34 Composition unit 36 Ground opening calculation unit

Claims (6)

Computer
Storing a predetermined range of DEM data in the first storage means;
Storing the predetermined range of DSM data in a second storage means;
Based on a predetermined plant height, a color value that is darker as the plant height is higher is assigned, and a color value that is lighter as the plant height is lower than the predetermined plant height is assigned. Storing the obtained color conversion table;
Generating a difference image between the DEM data of the first storage means and the DSM data of the second storage means as DHM data;
The z-value of each grid of the DHM data is read, the z-value is compared with the color conversion table, and the color value based on the color conversion table is assigned to the grid of the DHM data to thereby match the plant height according to the plant height. Generating color segmented image data;
Each grid of the DSM data of the first storage means is a point of interest, and a certain range is defined for each point of interest to determine the ground opening, the underground opening, and the slope. Generating DSM red stereoscopic image data in which a dark color is assigned each time the underground opening is large, and a color in which red is emphasized as the slope is large, respectively.
Generating DSM stereoscopic gray image data obtained by graying out the DSM red stereoscopic image data;
Multiplying the DSM stereoscopic gray image data and the plant high-color segmented image data to generate forest land stereoscopic image data in which each of the plant crowns is stereoscopically viewed in a color corresponding to the plant height. Forest land stereoscopic image generation method. The step of storing the color conversion table includes:
2. The forest land stereoscopic image generation method according to claim 1, wherein white is assigned to the minimum z value. The color conversion table is
3. The forest land three-dimensional image generation method according to claim 1, wherein the plant height and the color value are associated with each other according to the type of plant corresponding to the region. Computer
Storing a predetermined range of DEM data in the first storage means;
Storing the predetermined range of DSM data in a second storage means;
Based on a predetermined plant height, a color value that is darker as the plant height is higher is assigned, and a color value that is lighter as the plant height is lower than the predetermined plant height is assigned. Storing the obtained color conversion table;
Generating a difference image between the DEM data of the first storage means and the DSM data of the second storage means as DHM data;
The z-value of each grid of the DHM data is read, the z-value is compared with the color conversion table, and the color value based on the color conversion table is assigned to the grid of the DHM data to thereby match the plant height according to the plant height. Generating color segmented image data;
Each grid of the DEM data of the second storage means is a point of interest, and a certain range is defined for each point of interest to determine the ground opening, the underground opening, and the slope. Generating DEM red stereoscopic image data in which a dark color is assigned each time the underground opening is large, and a color in which red is emphasized as the slope is large, respectively.
Generating DEM yellowed red stereoscopic image data obtained by converting the DEM red stereoscopic image data to yellow;
Defining each grid of the DHM data as a point of interest, defining a certain range for each point of interest, obtaining a ground opening, and generating DHM ground opening image data in which the ground opening is assigned to each grid; ,
A method for generating a forest land three-dimensional image, comprising: generating a forest land three-dimensional image obtained by synthesizing the DEM red three-dimensional image data, DEM yellowed red three-dimensional image data, and DHM ground opening image data. The step of storing the color conversion table includes:
5. The forest land stereoscopic image generation method according to claim 4, wherein white is assigned to the minimum z value. The color conversion table is
6. The forest land three-dimensional image generation method according to claim 4, wherein the plant height and the color value are associated with each other according to the type of plant corresponding to the region.