JP5636227B2 - Ground 3D display system - Google Patents

Description

  The present invention relates to a system in which anyone can three-dimensionally understand the color distribution of resistivity information under the surface obtained by an airborne electromagnetic exploration method.

  There is a method (airborne electromagnetic exploration method) that confirms the electrical properties of the ground from the received signal obtained by emitting electromagnetic waves to the ground with this electromagnetic sensor while towing the electromagnetic sensor with a helicopter.

  This method is excellent in the extraction ability of the formation and the groundwater layer in which electricity easily flows, and is recommended because on-site access is unnecessary (see FIG. 30).

  As shown in FIGS. 31A and 31B, the exploration principle of the airborne electromagnetic method radiates electromagnetic waves from the transmission coils (FL, FH) of the magnetic sensor to the ground to generate a primary magnetic field. At this time, an eddy current is induced in the ground so as to cancel the change in the primary magnetic field.

  And the secondary magnetic field by an eddy current arises and the ratio (Ha / Hp) of the secondary magnetic field with respect to a primary magnetic field is measured. Then, the specific resistance is analyzed.

The specific resistance is “the electric resistance per unit length with respect to the current passing through the unit area, and the electric resistance R of a homogeneous conductor having a cross-sectional area S and a length L is
R = ρL / S
Ρ at this time is referred to as a specific resistance.

  On the other hand, Patent Document 1 discloses an aerial underground structure exploration method using electromagnetic waves. In Patent Document 1, an electromagnetic exploration bird is towed by an aircraft so as to cover an investigation target area, and a plurality of different primary magnetic fields are generated at an infinite number of positions in the sky, and the underground electromagnetic induction effect thereby is used. Collect secondary magnetic field information in the survey area.

  By combining the acquired secondary magnetic field information with the geographic information obtained by processing the topographic map of the survey area, a 3D geological structure model based on the underground 3D electrical property distribution is constructed.

  Based on this, the 3D visualization means running on the computer continuously changes the 2D or 3D image seen from any position including the ground and underground to the observation position or the observation direction. It can be displayed above.

  In paragraph 0022 of Patent Document 1, a huge amount of underground three-dimensional electrical characteristics (resistivity) acquired by aerial electromagnetic survey becomes basic information and is input to the system.

  It describes that the altitude values at regularly arranged grid points are mathematically calculated from irregularly distributed topographic data (XY coordinates) to generate a topographic surface.

  Paragraph 0023 describes that the magnetic property distribution of the ground surface based on the geomagnetic field intensity information acquired by the airborne electromagnetic exploration method is used.

Japanese Patent Laid-Open No. 2003-294853

  However, the coloring of the magnetic distribution is mostly based on experience and varies from reader to reader.

  Furthermore, even if appropriate coloring is performed, for example, even if the topography containing water is red in the plan view and the high resistivity part is blue, the unevenness of the ground surface is not easily seen visually. It is not easy to predict the future.

  An object of the present invention is to enable anyone to three-dimensionally understand the color distribution of resistivity information under the surface obtained by an airborne electromagnetic exploration method.

The ground three-dimensional display system of the present invention is obtained by measuring an electromagnetic induction phenomenon that occurs when an alternating magnetic field artificially generated by emitting electromagnetic waves from the air through a predetermined area is transmitted through the ground. A first database (100) in which the resistivity (p) of the ground below the surface of the earth is stored;
The ground opening calculated based on the DEM data and the ground opening image obtained by assigning a brighter color to the ground opening determined based on the DEM data of the mesh on the ground surface in the predetermined area. Each time, the terrain is composed of the difference image from the underground opening image assigned a darker color as the value of the underground opening increases, and the slope-enhanced image assigned the color value emphasized red as the inclination increases. A second database (110) in which the stereoscopic image (G1) is stored with the coordinates of the mesh and the RGB values of the terrain stereoscopic image (G1);
RGB values are read from the second database (110) for each mesh of the topographic stereoscopic image (G1), and the hue is changed from red to orange and the saturation is slightly reduced while leaving the property that the steep slope is red. , An HSV converter (140) for outputting this as a pale red terrain stereoscopic image (G3),
The specific resistance value (p) for each mesh in the first database (100) is read, and as the specific resistance value (p) decreases, the blue value is emphasized, and as the specific resistance value (p) increases, magenta is selected. A color table conversion unit (130) for outputting image data (F4) converted into enhanced RGB values;
The pale red terrain three-dimensional image (G3) before and hear error table conversion unit (130) image data (F4) and synthesizing unit for outputting the synthesized composite image (Mi) of from the (158),
The gist includes an output unit (160) that outputs and displays the composite image (Mi) from the synthesis unit (158) on a screen.

  As described above, according to the present invention, anyone can easily grasp the situation of the ground below the surface in three dimensions.

1 is a schematic configuration diagram of a ground stereoscopic display system of a first embodiment. It is explanatory drawing explaining specific resistance contrast data. It is explanatory drawing explaining specific resistance contrast data. It is explanatory drawing explaining topographical stereo image data G1. It is explanatory drawing of a color table conversion part (1). It is explanatory drawing of a color table conversion part (1). It is explanatory drawing of a color table conversion part (1). It is explanatory drawing explaining the concept of a color table conversion part (1). It is explanatory drawing explaining image data F2. It is explanatory drawing of the conversion process of the 2nd color table conversion part. It is explanatory drawing of the conversion process of the 2nd color table conversion part. It is explanatory drawing of the conversion process of the 2nd color table conversion part. It is explanatory drawing of synthetic | combination image FGa (it is also called image synthetic | combination type 1). It is a schematic block diagram of the ground solid display system of Embodiment 2. It is explanatory drawing of the conversion process in the 3rd color table conversion part. It is explanatory drawing of the conversion process in the 3rd color table conversion part. It is explanatory drawing of the conversion process in the 3rd color table conversion part. It is explanatory drawing explaining the image composition type 2. FIG. It is explanatory drawing explaining the light red red three-dimensional image G3. It is explanatory drawing explaining the conversion process of the image composition type 1 or the image composition type 2. It is explanatory drawing explaining the conversion process of the image composition type 1 or the image composition type 2. It is explanatory drawing explaining the conversion process of the image composition type 1 or the image composition type 2. It is explanatory drawing explaining the example of a screen at the time of changing the color table of a 2nd color table conversion part in steps. It is explanatory drawing of the image composition type 3. FIG. FIG. 25 is an explanatory diagram for explaining another example of the image composition type 2. In FIG. It is explanatory drawing explaining another example of the image composition type 3. FIG. It is explanatory drawing explaining another example of the image composition type 3. FIG. It is explanatory drawing explaining another example of the image composition type 2. FIG. It is explanatory drawing explaining another example of the image composition type 2. FIG. It is explanatory drawing of the air electromagnetic exploration method. It is explanatory drawing of the air electromagnetic exploration method.

  The present embodiment uses specific resistance contrast data F1 based on specific resistance data (Japanese Patent Application No. 2010-091934) and topographic stereoscopic image G1 (Japanese Patent Application No. 2004-368549).

(Resistivity contrast data)
The specific resistance contrast data F1 is obtained as follows.

  Electromagnetic exploration using an aerial electromagnetic exploration method using a helicopter is performed, and the ratio of the strength of the secondary magnetic field to the primary magnetic field in the investigation target ground is separated into an in-phase component and a phase-separated component.

  Then, the deviation due to drift is corrected for all of these separation data, and the measurement data subjected to this overall correction is divided into measurement data for each flight line, leveled, and the specific resistance value at each measurement point. Is calculated, and interpolation processing is performed to generate resistivity data in a grid format for each frequency, and input grid data including the resistivity data in the grid format and measurement data for each leveled flight survey line is generated. Then, grid leveling is performed on the input grid data, two-dimensional errors are excluded to obtain leveled grid data, and specific resistance data for each flight line is generated from the leveled grid data. This series of processing is called gridding.

  Based on the specific resistance data for each flight survey line, the specific resistance data between the flight survey lines is interpolated and gridding is performed again to generate specific resistivity data in grid format for each frequency. A three-dimensional resistivity model is created by combining the resistivity data in each grid format and the data of the digital elevation model.

  That is, a specific resistance model capable of extracting a specific resistance value at an arbitrary three-dimensional position is created by combining the generated specific resistance data in a grid format for each frequency and DEM data.

  For example, on the plane, specific resistance contrast data F1 is generated by associating the coordinates of the mesh (X, Y: 1 m, 10 m, for example) with a specific resistance value range (hereinafter simply referred to as specific resistance value p).

  In other words, the specific resistance value is the ratio of the output from the transmitting coil to the measured input at the receiving coil at the time of measurement, the unit is Ωm at the ppm level, and the measurable depth differs for each measurement frequency.

  If we look at the topographic map as it is, the order of change due to the difference in geology is much larger than the change due to the saturation level of the groundwater that we want to know most, and it was difficult to understand the correspondence between the topography and the groundwater. Therefore, a process was added to emphasize the local increase / decrease by removing the trend of the overall value change.

In particular
A Laplacian (second derivative) parameter * was obtained from 10m mesh resistivity data, and smoothing was applied to match the 1m resolution of the terrain.

  This is a specific resistance contrast image (specific resistance contrast data F1).

Note that the Laplacian is p (i, j)
-4 * p (i, j) + p (i-1, j) + p (i, j-1) + p (i + 1, j) + p (i-1, j) .

(Red stereoscopic image data G1: Also referred to as topographic stereoscopic image data G1)
The red stereoscopic image data G1 is obtained as follows.

  Reads the three-dimensional digital data (X, Y, Z) to which the elevation value of the ground surface within a predetermined range is given, restores the ground surface, and sets the height and coordinates of each grid (each mesh: 1 m) to the first DEM Second DEM data and a horizontal line that are generated as data and become the maximum vertex within a certain range in each of a plurality of directions from the first DEM data of the point of interest on the ground surface connecting the first DEM data. The ground opening obtained by averaging the angle vectors formed by and is obtained.

  Then, the ground opening image (Dp) obtained by assigning a brighter color as much as the value of the ground opening is obtained, and the inversion in which the solid with the air layer pressed against the first DEM data in a certain range is reversed. The second angle vector formed by the third DEM data, which is the maximum vertex within a certain range, and the horizontal line are obtained for each direction from the first DEM data at the point of interest of the DEM data, and averaged to obtain the second angle vector. Find the degree. Then, an underground opening image (Dq) is obtained in which a darker color is assigned to the magnitude of the value of the underground opening.

  Next, the ground opening image (Dp) and the underground opening image (Dq) are weighted and synthesized, and a first synthesized image (Dh: first topographic three-dimensional map image G1a) expressed in gradation according to this value. Say).

  In the above-mentioned ground opening image (Dp), when the ground opening value falls within the range of 40 degrees to 120 degrees, the first gray scale is obtained with the gradation in which 110 degrees is the brightest and 50 degrees is the darkest. By assigning it to the ground opening image, the larger the ground opening, the brighter the color.

  In addition, when the value of the underground opening is within the range of 40 degrees to 120 degrees, the second gray scale is assigned to the underground opening with a gradation in which 110 degrees is the darkest and 50 degrees is the brightest. The larger the opening, the darker the color.

  Further, the ground opening image (Dp) meshes the contour lines connecting the same Z values of the first DEM data on the ground surface, and the color data based on the first gray scale is displayed in the mesh region having the point of interest. A ground opening image (Dpa) assigned to the ground opening is generated, and the color gradation of the ground opening image (Dpa) is inverted to adjust the ridge to be white.

  Further, the ground opening image (Db) obtained by meshing contour lines connecting the same Z values of the first DEM data on the ground surface and assigning color data based on the second gray scale to the mesh area having the point of interest. ) Is generated, and when the color of the ground opening image Db becomes too black, the tone curve is corrected to a corrected color.

  On the other hand, the ground surface is meshed, and the average slope between the mesh of the target point and the adjacent mesh is obtained based on the first DEM data of each mesh, averaged, and output as an average slope. .

  Then, a difference image (Dra) between the ground opening image (Dp) and the underground opening image (Dq) is obtained, and the average inclination having the same elevation value as that of the difference image (Dra) is read. For each degree, an inclination-enhanced image (Dr) is obtained in which a color in which red is emphasized as the average inclination value increases.

  And let it be the 2nd synthetic | combination image (Ki: 2nd topographic solid image G1b) which synthesize | combined the said ground opening degree image (Dp), the underground opening degree image (Dq), and the said inclination emphasis image (Dr).

  In the above-described inclination-enhanced image (Dr), when the value of the inclination falls within the range of about 0 to 70 degrees, the third gray scale has the gradation that is brightest at 0 degrees and darkest at 50 degrees or more. Is assigned to the difference image (Dra) to obtain a gradient image (Dra) in which the color becomes black as the inclination increases, and R is emphasized by the RGB color mode function.

  Further, a three-dimensional image (Ki: third topographic three-dimensional image) in which the ridge is emphasized in red by synthesizing the slope-enhanced image (Dr) and the synthesized image (Dh) obtained by synthesizing by the first synthesizing unit. G1c).

  The following embodiments of the present invention exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is specified by the following configuration. It is not a thing. The technical idea of the present invention can be variously modified within the technical scope described in the claims.

<Embodiment 1>
FIG. 1 is a schematic configuration diagram of the ground stereoscopic display system of the present embodiment. As shown in FIG. 1, the ground display system of the present embodiment includes a database 100 that stores resistivity contrast data F1, a database 110 that stores topographic stereoscopic image data G1, a first color table conversion unit 101, a second color table conversion unit 105, a first HSV converter 108, and a first combining unit 11 5, stereoscopically displaying portion containing moisture in underground predetermined depth, the dry portion such To do.

  The specific resistance contrast data F1 stored in the above-described database 100, as shown in FIGS. 2 and 3, associates the coordinate X and Y of the mesh with a specific resistance contrast value range (simply referred to as a specific resistance value p). Is remembered.

  Further, in the database 110, the coordinates X and Y of the mesh are associated with the RGB values of the red stereoscopic image data G1 (see FIG. 4). The specific resistance contrast values are “1”, “2”.

  The first color table conversion unit 101 (lookup table) reads the specific resistance contrast data F1 (ridge: blue, valley: red) of the database 100 for each coordinate value, and the smaller the specific resistance value p, the more red (water And the tone conversion so that the specific resistance value p becomes larger (the dry portion that does not contain much: for example, a ridge). In other words, the part where the groundwater level is high is expressed in red.

  Specifically, the first color table conversion unit 101 converts the specific resistance value p into an RGB value as shown in FIGS. This table is also referred to as a conversion color table (1).

  That is, as shown in FIG. 8, the first color table conversion unit 101 performs conversion as shown in FIG.

  The image data F2 converted by the first color table conversion unit 101 (water-containing formation is red: valley is red, dry formation is blue: ridge is blue) is stored in the memory 103 (see FIG. 9). FIG. 9 shows an example in which contour lines are superimposed.

  As shown in FIG. 9, the smaller specific resistance value p is red, and the larger specific resistance value p is blue. For this reason, the part containing much water is red, and the part such as a dry ridge not containing much water is blue.

  In general, blue is a receding color and appears lower than the surroundings, and red is a progressive color and appears higher than the surroundings. That is, the ridge appears to be sinking because it is expressed in blue because the specific resistance value p is high, and the ridge appears red because the specific resistance value p is low in the valley. In other words, the correspondence with the actual topography is opposite, the ridge is blue and the valley is red.

  The first HSV conversion unit 108 reads the data of the topographic stereoscopic image data G1 from the database 110 for each of the mesh coordinates X and Y, converts it to gray scale, and stores it in the memory 109. The red three-dimensional map (gray-scaled terrain three-dimensional image data G2) in gray scale is expressed in gray close to bright white at the ridge and the summit.

  In the present embodiment, S (saturation) is lowered, H (hue) is shifted to the orange side, and V (lightness) is increased to make it gray.

  The above-described S (saturation) processing is referred to as saturation reduction processing, H (hue) processing is referred to as hue conversion processing, and V (lightness) processing is also referred to as lightness increase processing.

  The second color table conversion unit 105 uses cyan (where the specific resistance value p is low) in the mesh number and coordinate values of the first color table conversion unit 101 and the specific resistance contrast value range (collectively referred to as parameter B). (Light blue), the part with a large specific resistance value is changed to red (red).

  That is, the second color table conversion unit 105 is a table that changes the hue while maintaining the relationship between the saturation and the brightness with respect to the parameter B set in the first color table conversion unit 101 (conversion color table ( 2) or parameter B). This takes into account that light blue is a backward color and vermilion is a forward color. The image data F3 thus obtained (the valley is cyan and the ridge is vermilion) is stored in the memory 106.

  The processing of the second color table conversion unit 105 is specifically shown in FIGS.

  Here, the reason why the cyan-verbal conversion is adopted will be described.

  The second color table conversion unit 105 is not simply the image data F1 (ridge: blue, valley: red) inverted.

  When the image data F1 (ridge: blue, valley: red) is simply inverted, the red three-dimensional map in gray scale is expressed in dark gray in valleys and depressions.

  If the highly saturated blue blue color overlaps here, the terrain becomes almost unreadable due to visual characteristics.

  On the other hand, the red three-dimensional map in gray scale is expressed in gray close to bright white at the ridges and mountain peaks. A color with high red saturation overlaps with such a portion. As a result, the terrain is hardly readable due to visual characteristics. In consideration of this point, when the specific resistance value is small, the cyan color is adjusted to be gradually emphasized, and when the specific resistance value is large, the red color is adjusted to be gradually emphasized.

  Therefore, in the case of this color, even if the saturation is the maximum, the lightness is ensured, so that it is possible to recognize the topography by the red three-dimensional map converted to gray scale. In terms of the hue circle, the relationship between cyan and vermilion is close to the opposite color, which is almost complementary. Only in the case of a complementary color relationship, when a high value and a low value are repeated in a narrow range, it should look achromatic when viewed from a distance.

  However, the values that are not strictly complementary colors are adjusted in consideration of the stereoscopic effect on the display.

  The first synthesizing unit 115 superimposes the gray scaled red three-dimensional image G2 in the memory 109 and the cyan-red converted image data F3 (the valley is cyan and the ridge is vermilion) of the memory 106 in an overlapping manner. (Also referred to as type 1) is stored in the memory 120 (see FIG. 13).

  The output unit 160 outputs FGa (image composition type 1) in the memory 120 to the display unit 155 for display. The output unit 160 displays any image data of each memory on the screen according to the setting.

  As a result, as shown in FIG. 13, most of the ridge portions are vermilion and the landslide portion is cyan, and the relationship between the topography and water content can be understood very well. There are some ridges, cyan parts and valleys that are not light blue, so you can read various information.

<Embodiment 2>
However, the composite image FGa (image composition type 1) in which the gray scaled red three-dimensional map and the cyan-red converted image data F3 (the valley is cyan and the ridge is vermilion) is overlaid with the original red three-dimensional map. Is weak.

  Therefore, a third color table conversion unit and a second HSV conversion unit are newly provided.

  FIG. 14 is a schematic configuration diagram of the second embodiment. As shown in FIG. 14, in addition to the configuration requirements of the first embodiment, the second HSV conversion unit 140, the third color table conversion unit 130, the second synthesis unit 158, and the cyan color removal unit 151 Etc.

  The second HSV conversion unit 140 reads the red three-dimensional map in the database, changes the hue from the original red to orange while leaving the property that the steeper slope is red, and at the same time slightly reduces the saturation (see FIG. 19). Image data G3). However, it has been adjusted to cyan with a green valley.

  That is, S was changed from 0 ° (red) to 10 ° (red), the saturation was reduced by 10%, and the brightness was increased by 10%.

  The third color table conversion unit 130 reads the image data F1 (ridge: blue, valley: red) of the memory 100 for each coordinate (Xi, Yi) of the mesh, and the blue becomes stronger as the specific resistance value p decreases. As the specific resistance value increases, it is converted to magenta. That is, the cyan color is converted to blue and the vermilion color is converted to magenta (image data F4).

  FIG. 15, FIG. 16, and FIG. 17 show the relationship between the specific resistance contrast, which is the conversion process in the third color table conversion unit 130, and the color code. This is also referred to as a conversion color table (3).

  The second synthesizing unit 153 superimposes the light red red three-dimensional image G3 (image data G3) in the memory 141 and the image data F4 in the memory 131, and superimposes the superimposed image Mi (also referred to as image composition type 2). Is stored in the memory 150 (see FIG. 18).

  In order to obtain the above-mentioned Mi, the cyan color removing unit 151 removes the cyan color component where the red solid map contains a large amount of cyan in order to avoid the valley portion becoming too dark.

  Thereby, cyan is included when the value of the underground opening is 90 ° or more, and cyan becomes darker as the numerical value increases.

  This is a blue saturation reduction process because when the value of the parameter B is low, the color is blue, and the position overlaps with the valley, and a situation appears in reading the parameter B.

  Therefore, compared with the image composition type 1, the image composition type 2 makes it easier to see the topography in three dimensions.

  However, in terms of whether the value of the parameter B can be read directly, the image composition type 1 image may be easier to see.

  In such a case, the selection of the composite image type 1 or the selection of the composite image type 2 is set in the output unit 160, and either one is displayed on the screen.

  That is, as shown in FIGS. 20 to 22, the hue of the specific resistance value by the color table conversion (1) is converted as in the color table conversion (2) or the color table conversion (3), and the image composition type 1 or Image composition type 2 is obtained.

<Embodiment 3>
All the color tables so far are expressed in gradation. In order to express with gradation, the relationship between the terrain and the parameters can be handled relatively without determining a threshold value in advance.

  However, it was difficult to compare the value of parameter B between two distant points.

  For this reason, the color table of the second color table conversion unit is changed stepwise, so that the total is 7 gradations. The state of change of parameter B can also be read as an isoline (see FIG. 23).

When this is combined with the image Mi (also referred to as image composition type 3: see FIG. 24), the range including the water of the terrain is found in a contour line, and the three-dimensional effect of the terrain is easily understood.

  FIG. 25 shows an example of image composition type 2. As shown in FIG. 25, the low resistivity contrast map overlaps the swamps by combining the red part (steep slope), dark part (valley and swamp part) of the red three-dimensional map with the hue of the resistivity contrast diagram. Etc. are consistent with the terrain expression, making it easier to understand the distribution of terrain and resistivity contrast.

  In addition, by superimposing the red three-dimensional maps, it is possible to easily identify a portion with a steep ridge and weathering (high specific resistance).

  Furthermore, it was possible to recognize landslide blocks made of collapsible soil with high groundwater or high water content even in the same landslide topography, making it possible to judge danger.

  An example of image composition type 3 is shown in FIGS. FIG. 26 displays the contour lines in an overlapping manner. In the figure, it is a range including blue pieces, and this place has a lower specific resistance than the surroundings, and it is estimated that the collapse rate is high but the groundwater level is high but saturation is high. There is a high possibility of sediment discharge due to the development of gully below.

The red part is said to have high specific resistance and low near water level. In (2), gully is developed, and caution is required for falling rocks and collapse.

  Furthermore, an example of image composition type 2 is shown in FIGS. In FIG. 28, it is estimated that the blue part has a low specific resistance compared to the surrounding area, and a collapsed soil with high groundwater or high water content is distributed. In the field survey, wetlands were identified in this blue area. FIG. 28 is a bird's eye view.

  Then, in FIG. 28, it can be seen that the gully develops in the part (1) and the possibility of sediment discharge is high.

  In the red area, the specific resistance is high and the groundwater level is low or weathering proceeds, and the gap is estimated. The point (2) is confirmed to be loose at the site, and rockfall and collapse are presumed.

  Therefore, disaster factors such as landslides, collapses, and faults can be grasped in three dimensions without entering the site.

  The image data may be printed or output to a computer externally.

In addition, the ground state stereoscopic visualization display device according to the present embodiment includes a central information processing device (CPU) including an appropriate combination of a processor, a microcomputer, a logic, a register, and the like, and control / operation necessary for the central information processing device. An information input unit including a keyboard (KB) for inputting information, a mouse, an interactive soft switch, an external communication channel, and the like, a display, a database, a memory, and the like. 2, a program that functions as a third color table conversion unit, first and second synthesis units, first and second HSV conversion units, a cyan color removal unit, and the like is stored.

100 Database 110 Database 101 First color table conversion unit 105 Second color table conversion unit 108 First HSV conversion unit

Claims (2)

Specific resistance value of the ground below the surface for each mesh obtained by measuring the electromagnetic induction phenomenon that occurs when an alternating magnetic field artificially generated by emitting electromagnetic waves from the air through a given area is transmitted through the ground. A first database (100) in which (p) is stored;
The ground opening calculated based on the DEM data and the ground opening image obtained by assigning a brighter color to the ground opening determined based on the DEM data of the mesh on the ground surface in the predetermined area. Each time, the terrain is composed of the difference image from the underground opening image assigned a darker color as the value of the underground opening increases, and the slope-enhanced image assigned the color value emphasized red as the inclination increases. A second database (110) in which the stereoscopic image (G1) is stored with the coordinates of the mesh and the RGB values of the terrain stereoscopic image (G1);
RGB values are read from the second database (110) for each mesh of the topographic stereoscopic image (G1), and the hue is changed from red to orange and the saturation is slightly reduced while leaving the property that the steep slope is red. , An HSV converter (140) for outputting this as a pale red terrain stereoscopic image (G3),
The specific resistance value (p) for each mesh in the first database (100) is read, and as the specific resistance value (p) decreases, the blue value is emphasized, and as the specific resistance value (p) increases, magenta is selected. A color table conversion unit (130) for outputting image data (F4) converted into enhanced RGB values;
The pale red terrain three-dimensional image (G3) before and hear error table conversion unit (130) image data (F4) and synthesizing unit for outputting the synthesized composite image (Mi) of from the (158),
A ground stereoscopic display system comprising: an output unit (160) that outputs and displays a composite image (Mi) from the synthesis unit (158) on a screen. The ground according to claim 1, further comprising: a cyan color removing unit (151) that reads data of the pale red terrain stereoscopic image (G3) for each mesh and removes a cyan value of a predetermined value or more. 3D display system.