JP5795283B2 - Visual elevation image creation method and visualization image creation apparatus for digital elevation model - Google Patents

Description

The present invention uses conventional altitude maps obtained from the base map information (10m mesh elevation points and 5m mesh elevation points) published by the Geospatial Information Authority of Japan, and aerial laser surveys, etc. The present invention relates to a visualized image creating method and a visualized image creating apparatus for facilitating interpretation of collapsed areas, ridge valleys, topographic lineaments and the like that could not be grasped only by a topographic analysis method such as a figure.

The base map information is defined as “the location of geospatial information based on the provisions of Article 2, Paragraph 3 of the Geospatial Information Utilization Promotion Law (Act No. 63 of 2007), which was enforced on August 29, 2007. This is map information that serves as a “standard for,” and can be used freely by anyone as common white map data in a geographic information system (hereinafter “GIS”).

Among these, the digital elevation model (Digital Elevation Model), which records elevation data, has been prepared and published as data at 10 m intervals nationwide (hereinafter referred to as “DEM”). (10mDEM is DEM maintained at 10m intervals)

In recent years, 2mDEM and 1mDEM with higher density than 10mDEM have been acquired by aerial laser surveying and used by related ministries, prefectures and municipalities. These are not disclosed, but there are some places that are published as 5mDEM as public survey results in the Geographical Survey Institute's base map information.

Topographic analysis using DEM has been performed for a long time, and a representative analysis method is a slope map. The slope map is an image calculated from the elevation of the target point of the DEM and the elevations of the surrounding points, and is useful for grasping steep or loose locations. The amount of information that can be read increases as the DEM density increases. However, ridges, valleys, and landslides sometimes have the same slope, which may be difficult to grasp.

In addition, there are other analysis methods such as contour lines, curvature, and hillshading, but each has its advantages and disadvantages, and interpretation of the topography (extraction of ridges, valleys, collapsed areas, etc.) may be difficult.

In Patent Document 1, the degree of inclination is calculated using three-dimensional digital data (X, Y, Z), and a red gradation is displayed according to the maximum degree of inclination so that the red becomes darker as the inclination becomes steep. In addition, a visualization processing system is disclosed that generates a gradient reddish three-dimensional image in which the ridges are whitish and the valleys are darkened by displaying the lightness of red according to the degree of ups and downs representing the degree of unevenness. Yes. Also, in this Patent Document 1, a composite image of a gray scale corresponding to the ground opening and a gray scale corresponding to the underground opening is combined with a red image corresponding to the inclination, thereby obtaining a reddish three-dimensional image. A configuration to generate is also disclosed.

In Patent Document 2, the topographic data of a concave portion in which a concave and convex portion is detected by a spatial moving average and a cold color is given to the concave portion, the topographic data of the convex portion to which a warm color is given to the convex portion, and flatness are disclosed. Shade terrain data is created by combining the terrain data of each part, and base images at the same position (for example, shadow images, color elevation images, contour map images, gradient images, etc.) are mixed at an appropriate mixing ratio. Thus, a stereoscopic image creating apparatus that creates a stereoscopic image is disclosed.

In Patent Document 3, a color elevation slope map is created by transparently synthesizing a high-level chroma chart (color elevation chart) assigned to hue and the like from DEM elevation data and a grayscale slope map assigned with a darker density as steep slopes. A method for creating a color elevation slope map is disclosed.

In Patent Document 4, based on elevation data such as DEM, the hue determination unit generates hueed elevation data, the luminance determination unit generates sunlight reflection intensity data, and the unevenness correction unit generates fine unevenness information. Generate correction data. There is disclosed a topographic map creation method in which image data is generated from an HSI color space by an image composition unit, and the saturation used at this time is determined from the processing result of the unevenness correction unit.

In Patent Document 5, based on the three-dimensional terrain data including the altitude of the terrain, the altitude step data generated by giving the color according to the altitude value of the target point and the color according to the ridge valley degree of the target point are given. Terrain terrain image generation method is disclosed, which generates terrain terrain data by multiplying and synthesizing the ridge and valley grading data generated in this way with the shade corresponding to the slope of the target point. .

Japanese Patent No. 4272146 Japanese Patent No. 4379264 Japanese Patent No. 4771459 JP 2008-242298 A JP 2012-3400 A

In the reddish stereoscopic image of Patent Document 1, the ridge and valley are emphasized and a stereoscopic image is provided. However, the valley portion may be dark and may be difficult to read. In Patent Document 2, ridges and valleys are emphasized in the same manner as Patent Document 1, but it is necessary to create different data by changing the spatial frequency in order to distinguish between a fine recess and a large recess. In the color elevation slope map of Patent Document 3, the elevation and slope were easy to read simultaneously, but it was sometimes difficult to distinguish the ridge and valley from the slope. In the topographic map of Patent Document 4, because the unevenness is corrected from the elevation value, the unevenness is more emphasized, so that the hue may change depending on the elevation value even in the same unevenness.

The present invention has been made paying attention to the above-mentioned problems, and its purpose is to provide a visualization image creation method and a visualization image creation device that make it easier to read the collapsed lands, ridge valleys, and terrain lineaments from the DEM. is there.

To achieve the above object, a first aspect of the present invention, the visible image creating a digital elevation model, the irregularity value detecting step of calculating the irregularity value of the target point of DEM, detected by the irregularity value detection procedure The unevenness value conversion procedure for converting the unevenness value into a numerical value of 5 to 95, the luminance calculation procedure for calculating the luminance from the converted numerical value, the inclination calculation procedure for calculating the inclination of the target point, and the inclination A gradient image generation procedure for generating a gradient image from the image, a saturation calculation procedure for calculating a saturation from the gradient and the converted numerical value, and determining an appropriate hue and using an HSB color space. Image generation procedure using HSB color space for generating one image, and 50% transmission image of the gradient image is a composite color, and the first image is a basic color and the composite color is brighter than 50% gray Multiplying the composite color and the basic color, the composite color Is darker than 50% gray , a composite image generation procedure for generating a composite image obtained by multiplying the composite color and the basic color and multiplying the composite image to form a second image, and the gradient image and the second image are This is a transparent composite image generation procedure for generating a visualized image of a digital elevation model by transparent combination.

According to a second aspect of the present invention, in the method for creating a visualized image of a digital elevation model according to the first aspect of the invention, in the unevenness value detection procedure, data in a certain range (5 × 5 or more) of the target point (point of interest) of the DEM Thus, the difference between the elevation value of the point of interest and the elevation value in each of the eight directions is taken, and the unevenness value is detected from the cell having the largest absolute value in each of the eight directions and the elevation value of the point of interest.

A third invention is the visible image creating a digital elevation model according to the first invention, in the uneven value conversion procedure, it sets the threshold unevenness value detected by the irregularity value detection procedure, threshold The numerical value is converted into a numerical value of 5 to 95 in the range of values.

According to a fourth aspect of the present invention, in the method for creating a visualized image of a digital elevation model according to the first aspect, the luminance calculation procedure calculates the luminance of the HSB color space from the converted numerical value.

According to a fifth aspect of the present invention, in the method for creating a visualized image of a digital elevation model according to the first aspect of the invention, in the saturation calculation procedure, the saturation of the HSB color space is calculated from the gradient and the converted numerical value. A method for creating a visualized image of a digital elevation model according to claim 1.

According to a sixth aspect of the present invention, in the method for creating a visualized image of a digital elevation model according to the first aspect of the present invention, in the image generation procedure using the HSB color space, an image in the HSB color space is obtained from the luminance, the saturation, and the hue. Is generated.

According to a seventh aspect of the present invention, in the method for creating a visualized image of a digital elevation model according to the first aspect, in the synthetic image generation procedure, a 50% transmission image of the gradient image is used as a synthetic color, and the synthetic image is used as a basic color. , If the color is brighter than 50% gray, the composite color and the base color are multiplied and combined. If the composite color is darker than 50% gray, the composite color and the base color are inverted and multiplied to generate the image. It is.

According to an eighth aspect of the present invention, in the method for creating a visualized image of a digital elevation model according to the first aspect of the invention, in the transparent synthesized image generation procedure, the gradient image and the synthesized image are transparently synthesized to generate a visualized image of the digital elevation model. It is made to generate.

A ninth aspect of the present invention is a digital elevation model visualizing image creating apparatus, wherein an unevenness detecting unit for detecting an unevenness value at a DEM target point, and an unevenness value threshold setting for setting an unevenness value threshold , A concavo-convex value conversion unit that converts the extracted concavo-convex value into a numerical value of 5 to 95, a luminance calculation unit that calculates luminance from the converted numerical value, and a gradient calculation unit that calculates the gradient from the DEM A gradient image generation unit for generating a gradient image from the gradient, a saturation calculation unit for calculating a saturation from the gradient and the converted numerical value, and using an HSB color space that gives an appropriate hue When the image generation unit using the HSB color space for generating the first image and a 50% transmission image of the gradient image are combined colors and the first image is a basic color, the combination color is brighter than 50% gray. Multiplies and synthesizes the composite color with the basic color, and the composite color is 50% gray In the case of darkness, a composite image generation unit that generates a second image by inverting and multiplying the composite color and the basic color, and a transparent image of the digital elevation model by transparently combining the gradient image and the second image A transparent composite image generation unit for generating the image, an image display unit for displaying the visualized image of the digital elevation model, and an image printing unit for printing the visualized image of the digital elevation model.

According to the present invention, the unevenness value image by the DEM and the gradient image are synthesized, and an image showing a bright color at the ridge and a dark color at the valley is generated. In this image, in addition to the information shown in the slope map, it is possible to create a visualization image of a digital elevation model that makes it easier to read ridges, valleys, collapsed areas, topographic lineaments, and the like.

It is a flow which shows embodiment of the visualization image creation method of the numerical elevation model concerning this invention. It is a flow which shows embodiment of the visualization image creation apparatus of the numerical elevation model concerning this invention. It is an attention point cell which shows the acquisition state of a numerical elevation model. It is a figure which shows the comparison direction for detecting the uneven | corrugated value of topography. It is a figure which shows the cell where an absolute value becomes the largest compared in each direction. An example in which the threshold value of the concavo-convex value is converted to a numerical value from 5 to 95 with ± 100 is shown. It is a figure which shows the example of the synthesized image I2 by a compositing process. FIG. 7 shows an example of a composite image I3 obtained by the transmission image synthesis process of the gradient image. It is an image which shows the example of the inclination image Is. It is a figure which shows the example of the gray scale image which shows an unevenness | corrugation detection result. It is a figure which shows the example of the image I1 using HSB color space. It is a figure which shows the example which changed the hue of the inclination image Is according to the inclination. (In this example, the color changes from dark blue-green to light blue-green.) It is a figure which shows the example of a hillshade figure.

FIG. 1 shows a flow showing an embodiment of a method for creating a visualized image of a digital elevation model according to the present invention. In FIG. 1, S1 to S12 show an execution procedure of the method for creating a visualized image of a digital elevation model according to the present invention. And the form for implementing this invention is demonstrated according to FIG.

The embodiment of the present invention is realized by a program operating on a personal computer or a workstation. FIG. 2 shows the configuration of a personal computer or workstation, and shows one embodiment of a digital elevation model visualization image creation apparatus according to the present invention. In FIG. 2, the visualized image creating apparatus includes a terrain unevenness value detecting unit 1, a gradient calculating unit 2, a gradient image generating unit 3, an unevenness value threshold setting unit 4, an unevenness value linear converting unit 5, Degree calculation unit 6, luminance calculation unit 7, hue setting unit 8, image generation unit 9 by HSB color space, synthesized image generation unit 10, image synthesis 11 by transmission synthesis, image display unit 12 and print processing unit 13 It is comprised including.

The digital elevation model acquisition unit 14 (S1) acquires data within a certain range including a cell (point of interest) on the DEM as shown in FIG. Here, a case of 9 × 9 will be described. The size may be changed to 13 × 13 or the like as necessary, but it is set to 5 or more. However, it is an odd number × odd number.

The topographic unevenness detection unit 1 (S2) is realized by a program operating on a personal computer or a workstation. From the point of interest and a certain range of data (here 9 × 9), the altitude value α of the point of interest is compared with the comparison data in each of the eight directions as shown in FIG. 4, and the cell with the largest absolute value is obtained. Each elevation value is stored in a memory.

When the cell having the largest absolute value in each direction as shown in FIG. 5 is obtained as shown in FIG.

From the above formula, it can be determined that a positive value is convex and a negative value is concave. From this numerical value Ov, it is easy to distinguish between ridges and valleys by imaging the state of unevenness. The calculated numerical value Ov is stored in a memory or a hard disk drive (hereinafter referred to as “HDD”).

The inclination calculation unit 2 (S4) is realized by a program operating on a personal computer or a workstation. Here, the gradient is calculated from the DEM, and the gradient image generation unit 3 (S5) forms an image Is as shown in FIG. At this time, the calculation method is not limited as long as the inclination is in the range of 0 to 90 °. Basically, it is created using a GIS application. The generated image Is is stored in a memory or HDD.

The unevenness conversion unit 5 (S3) is realized by a program operating on a personal computer or a workstation. Here, the numerical value Ov is displayed by an image processing application, a GIS application, etc., the color tone is adjusted so that the degree of unevenness can be understood, and the threshold value of the convex part and the threshold value of the concave part are determined (T). Here, the threshold value of the convex portion and the threshold value of the concave portion may be the same value with opposite signs. An example in which the determined threshold value is linearly converted (Y) by the following equation is shown. FIG. 6 is an image when the threshold value is set to ± 100.
Y = (45 / T) x Ov + 50
here,
Y = 5, Y = 5
Y = 95, Y = 95

By the conversion, the numerical value of Ov is linearly converted to a range of 5 to 95.

The saturation calculation unit 6 (S6) is realized by a program operating on a personal computer or a workstation. Here, the saturation (0.0 to 1.0) of the HSB color space is calculated using the Ov and SL at the same position. The saturation Sv is calculated by the following equation. Sv = 0.5 × Ov × 0.01 + 0.5 × SL × 0.01

The luminance calculation unit 7 (S7) is realized by a program operating on a personal computer or a workstation. Here, the luminance (0.0 to 1.0) of the HSB color space is calculated using the Ov. The brightness Bv is calculated by the following formula. Bv = Ov × 0.01

The hue setting unit 8 (S8) is realized by a program operating on a personal computer or a workstation. Here, the hue Hv for image creation using the HSB color space is determined. The hue is specified in the range of 0 ° to 360 °. The orange to brown range often shows good results.

The image generation unit 9 (S9) using the HSB color space is realized by a program operating on a personal computer or a workstation. Here, using the HSB color space, an image I1 is created from Hv, Sv, and Bv at the same position as shown in FIG. 11 and stored in the memory or HDD.

The composite image generation unit 10 (S10) is realized by a program that operates on a personal computer or a workstation. Here, the image of I1 is combined with the image of I1 with the gradient image Is having a transmittance of 50% as the combined color. When Is is darker than 50% gray, it is darkened by multiplying the colors of Is and I1, and when Is is lighter than 50% gray, Is and I1 are inverted. An image is synthesized by a process for making the image brighter by multiplying and synthesizing the generated colors to create a synthesized image I2 as shown in FIG.

Such processing is called hard light synthesis in the widely used PHOTOSHOP (registered trademark) of ADOBE.

Since the contrast of the image of I1 is further emphasized by this synthesis processing, the distinction between the ridge R and the valley N, the collapsed portion F, the terrain lineament, and the like are clearly displayed.

At this time, the Is image is not grayscale, and a color image in which the saturation is changed as shown in FIG. 12 may be used on the image processing software. The generated composite image I2 is stored in a memory or HDD.

Finally, the transmission composite image generation unit 11 (S11) sets a gray scale in which a portion with a low inclination is bright and a portion with a steep inclination is darkened, and an image of Is and an I2 set with an appropriate transmittance are set. The images are transparently synthesized to synthesize an image I3 as shown in FIG.

By this processing, it is possible to finely adjust a portion that is too bright or a portion that is too dark. The generated image I3 is stored in the memory or HDD.

The transparent composite image I3 becomes a visualized image of a digital elevation model. The image display unit 12 (S12) displays the transparent composite image I3 on a display attached to a personal computer or workstation.

DESCRIPTION OF SYMBOLS 1 ... Topographic unevenness value detection part 2 ... Inclination degree calculation part 3 ... Inclination degree image generation part 4 ... Unevenness value threshold value setting part 5 ... Unevenness value linear conversion part 6 ... Saturation calculation part 7 ... Luminance Calculation unit 8 ... Hue setting unit 9 ... Image generation unit by HSB color space 10 ... Composite image generation unit 11 ... Image synthesis by transmission synthesis 12 ... Image display unit 13 ... Print display unit 14 ... Digital elevation model acquisition unit
S1… Procedure for obtaining digital elevation model
S2 ... Procedure for detecting unevenness value of topography
S3 ... Procedure for converting unevenness value of terrain into 5 to 95
S4… Procedure for calculating the slope
S5… Procedure for creating a gradient image
S6 ... Procedure for calculating saturation in HSB color space
S7 ... Procedure for calculating luminance in HSB color space
S8 ... Procedure for calculating hue in HSB color space
S9 ... Procedure for calculating images in HSB color space
S10 ... Procedure for generating an image by composition processing
S11 ... Procedure for generating an image by transparent composition processing
S12: Means for displaying an image F ... Location of collapse N ... Valley RR ... Ridge
Ov ... Roughness value
V: Value obtained by converting the unevenness value
SL ... Inclination (unit: degree)
Bv: Luminance in HSB color space
Sv: Saturation in HSB color space
Hv ... Hue in HSB color space
HSB: Color space consisting of three components: Hue, Satulation, and Brightness
GIS: Geographic Information System
DEM… Digital Elevation Model

Claims (9)

The unevenness value detection procedure for calculating the unevenness value of the target point of the DEM, the unevenness value conversion procedure for converting the unevenness value detected by the unevenness value detection procedure into a numerical value of 5 to 95, and the luminance from the converted numerical value. A luminance calculation procedure for calculating, a gradient calculation procedure for calculating the gradient of the target point, a gradient image generating procedure for generating a gradient image from the gradient, and a saturation from the gradient and the converted numerical value A saturation calculation procedure for calculating the image, an image generation procedure using the HSB color space for determining an appropriate hue and generating the first image using the HSB color space, and a 50% transmission image of the gradient image the composite color, as the basic color of the first image, when the composite color is lighter than 50% gray synthesis by multiplying the composite color and the base color, if the composite color is darker than 50% gray, the composite color and the base color generating a multiplication synthesized composite image by inverting the color Digital Elevation Model of the composite image generation procedure to the second image, characterized by comprising a transparent composite image generating procedure for generating a visualization of the gradient image and the second image transmitted synthetic Digital Elevation Model Visualization image creation method. In the unevenness detection procedure, the absolute value of each of the eight directions is obtained by taking the difference between the elevation value of the point of interest and the elevation value of the eight directions from the data of a certain range (5 × 5 or more) of the target point (target point) of the DEM. The method for creating a visualized image of a numerical elevation model according to claim 1, wherein the unevenness value is detected from the cell having the largest value and the elevation value of the point of interest. The numerical elevation model according to claim 1, wherein in the unevenness value conversion procedure, a threshold value of the unevenness value detected by the unevenness value detection procedure is set and converted to a numerical value of 5 to 95 within the threshold range. Visualization image creation method. The method of creating a visualized image of a numerical elevation model according to claim 1, wherein in the luminance calculation procedure, the luminance of the HSB color space is calculated from the converted numerical value. The method for creating a visualized image of a numerical elevation model according to claim 1, wherein, in the saturation calculation procedure, the saturation of the HSB color space is calculated from the gradient and the converted numerical value. The method of creating a visualized image of a digital elevation model according to claim 1, wherein in the image generation procedure using the HSB color space, an image in the HSB color space is generated from luminance, saturation, and hue. In the composite image generation procedure, a 50% transmission image of a gradient image is a composite color, and the composite image is a basic color. If the image is brighter than 50% gray, the composite color is multiplied by the basic color, and the composite color is darker than 50% gray. The method according to claim 1, wherein the image is generated by inverting and multiplying the synthesized color and the basic color to generate an image. 2. The method of creating a visualized image of a digital elevation model according to claim 1, wherein, in the transparent composite image generation procedure, a visualization image of the digital elevation model is generated by transparently combining the gradient image and the composite image. Concavity and convexity detection unit (1) for detecting the concavo-convex value at the target point of DEM, concavo-convex value threshold setting unit (4) for setting the concavo-convex value (Ov) threshold, and extracted concavo-convex value The unevenness value conversion unit (5) for converting (Ov) into a numerical value (V) of 5 to 95, the luminance calculation unit (7) for calculating the luminance (Bv) from the converted numerical value, and the slope ( (SL), an inclination image generation unit (3) that generates an inclination image (Is) from the inclination (SL), and the inclination (SL) and the converted value. The saturation calculator (6) that calculates the saturation (Sv) from the numerical value (V) and the HSB color space that gives the appropriate hue and uses the HSB color space to generate the first image (I1) image generating unit (9), 50% transmission image combining color of the gradient image (is), said first image (I1) as a base color, if the composite color is lighter than 50% gray, and combined color Multiply the basic colors and the composite color is darker than 50% gray In this case, a composite image generation unit (10) that generates a second image (I2) by inverting and multiplying the composite color and the basic color, and the gradient image (Is) and the second image (I2) ) To generate a visualization image of a digital elevation model (11), an image display unit (12) to display a visualization image of a digital elevation model, and a visualization image of a digital elevation model image printing unit (13) and the visible image generating apparatus of the digital elevation model comprising the.