JP7404030B2 - Enhanced image model creation system - Google Patents

Description

The present invention relates to a technique for expressing topography, and more specifically, to an enhanced image model creation system for creating an image whose brightness is emphasized depending on the distance from a viewpoint, for example.

Japan is known as a country where earthquakes occur frequently, and in recent years major earthquakes have occurred, including the Tohoku Pacific Coast Earthquake, the Southern Hyogo Prefecture Earthquake, and the Eastern Hokkaido Iburi Earthquake, each of which has caused significant damage. For example, in the Hyogo Prefecture Southern Earthquake, many houses collapsed due to the impact of a strong direct earthquake, and in the Great East Japan Earthquake, a large number of houses were devastated by the tsunami.

It is said that there are approximately 2,000 active faults in the land area of Japan, but the locations of all active faults are not clear, and various organizations including the Ministry of Education, Culture, Sports, Science and Technology are currently conducting intensive investigations. is in progress. Investigation methods for active faults include on-site investigations such as topographical observation, field surveying, trench surveys, and geophysical surveys such as elastic wave surveys, as well as desk investigations such as aerial photo interpretation.In general, desk investigations are first carried out. We identify potential active faults that are suspected to be active faults, and then conduct detailed on-site surveys of specific active fault candidates.

Aerial photo interpretation, which has traditionally been carried out as a desk survey, involves arranging two aerial photographs taken of the topography by an aircraft, and using 3D viewing to read the undulations of the topography and determine the presence of active faults. It is something. This aerial photo interpretation requires skill, so it cannot be performed by anyone, and it is extremely difficult to show a stereoscopic image to someone else.

On the other hand, with the advancement of computer performance and information technology, in recent years there has been an increasing number of cases in which terrain is treated as a three-dimensional terrain model (hereinafter referred to as a "digital elevation model"). This digital elevation model includes a digital surface model (DSM) that includes trees and buildings covering the ground surface (hereinafter referred to as "coverings") as a topographic model, and a digital surface model (DSM) that includes the pure ground surface excluding coverings. An example of this is a digital elevation model (DEM). In any case, the digital elevation model can be processed by a computer and enables three-dimensional expression.

Methods to express terrain three-dimensionally using digital elevation models include creating orthogonal projection images such as shaded maps, slope maps, and elevation maps, or bird's-eye views that make it easy to understand the relief and depth of features. There are known methods for creating it. Further, in Patent Document 1, which was filed by the applicant of the present application prior to this application, a DEM is created from point cloud data obtained by aerial laser measurement, and topographical quantities such as slope amount and elevation value are assigned to each mesh of the DEM, We are proposing a system that creates a color elevation map (elevation graded map) and a grayscale slope map based on this topographical amount, and then creates a color elevation slope map by combining the color elevation map and the grayscale slope map.

JP2007-48185

By the way, when people look at their surroundings in dim darkness, it is difficult to grasp the sense of distance, and it is also difficult to perceive the scenery in three dimensions. On the other hand, by illuminating the dim darkness with a flashlight, it becomes possible to grasp the sense of distance in the direction of the person's line of sight, and it becomes possible to see the surroundings three-dimensionally and clearly. However, regarding the method of expressing the terrain three-dimensionally, a method that produces the effect of illuminating light (hereinafter referred to as the "headlight effect") has not been adopted. In other words, conventional methods such as shading maps, slope maps, elevation maps, bird's-eye views, or color elevation slope maps according to Patent Document 1 do not produce a headlight effect, and in other words, realize expressions close to those seen by the human eye. It wasn't.

An object of the present invention is to solve the problems faced by the prior art, that is, to provide an enhanced image model creation system that enables three-dimensional representation of terrain in which a headlight effect can be expected.

The present invention focuses on adjusting the brightness of each pixel according to the distance from the viewpoint, for example, and is an invention based on an idea that did not exist in the past.

The enhanced image model creation system of the present invention is a system that creates an "enhanced image model" using a "basic image model" composed of a plurality of pixels (pixels having plane position information), and includes line-of-sight distance calculation means. It is equipped with emphasis color information setting means. Note that color information including brightness is given to each pixel constituting the basic image model. The line-of-sight distance calculation means is a means for reading out the basic image model and calculating a "line-of-sight distance" for each pixel, which is a straight-line distance from a preset reference point to the pixel. The emphasis color information setting means sets "emphasis color information" in which the brightness of the color information is changed according to the line-of-sight distance for each pixel, and the emphasis color information is set so that the shorter the line-of-sight distance, the brighter it becomes. Set. Then, an emphasized image model is created by assigning emphasized color information to each pixel.

The enhanced image model creation system of the present invention can also create an enhanced image model based on two or more preset reference points. In this case, the line-of-sight distance calculation means calculates line-of-sight distances for each pixel with respect to two or more reference points, and the emphasis color information setting means sets emphasis color information for each pixel based on the two or more line-of-sight distances.

The enhanced image model creation system of the present invention may further include a reference point moving means and a drawing means. The reference point moving means is means for moving the reference point, and the drawing means is means for drawing an image in which emphasized color information is output for each pixel. In this case, the line-of-sight distance calculation means calculates the line-of-sight distance for each pixel as the reference point moves, and the emphasis color information setting means sets emphasis color information for each pixel as the reference point moves, and then draws The means draws an image as the reference point moves.

The enhanced image model creation system of the present invention can also create an enhanced image model based on a reference plane (instead of a reference point). In this case, the line-of-sight distance calculation means calculates the line-of-sight distance, which is the shortest distance from a preset reference plane to the pixel, for each pixel.

The enhanced image model creation system of the present invention can also create an enhanced image model based on a basic image model in which each pixel has height information. In this case, the line-of-sight distance calculation means calculates the line-of-sight distance based on the plane position information and height information of the pixel.

The enhanced image model creation system of the present invention can also determine the brightness coefficient according to the line-of-sight distance and set the emphasized color information by multiplying the brightness by this brightness coefficient. In this case, the brightness coefficient can also be determined according to the square of the line-of-sight distance.

The enhanced image model creation system of the present invention has the following effects.
(1) The image drawn based on the enhanced image model according to the present invention allows a three-dimensional understanding of the terrain more realistically (in a state close to that seen by the human eye) due to the headlight effect.
(2) Since a ready-made image model (basic image model) can be used, an enhanced image model can be created relatively easily and at low cost.

(a) is a topographical image drawn based on the basic image model, and (b) is a topographical image drawn based on the enhanced image model. A model diagram schematically showing a basic image model. FIG. 1 is a block diagram showing the main configuration of the enhanced image model creation system of the present invention. FIG. 2 is a flowchart showing the main processing flow of the enhanced image model creation system of the present invention. FIG. 3 is a model diagram schematically showing the line-of-sight distance from a reference point in a pixel having only plane coordinates. FIG. 3 is a model diagram schematically showing the line-of-sight distance from a reference point in a pixel having three-dimensional coordinates. FIG. 3 is a model diagram schematically showing line-of-sight distance when two reference points are set. FIG. 3 is a flowchart showing the main processing flow of the enhanced image model creation system when moving the reference point. FIG. 2 is a model diagram schematically showing the line-of-sight distance from a reference plane for pixels having only plane coordinates. FIG. 3 is a model diagram schematically showing the line-of-sight distance from a reference plane at a pixel having three-dimensional coordinates.

An example of an embodiment of the enhanced image model creation system of the present invention will be described based on the drawings.

1. Overall Overview The present invention utilizes a model (hereinafter referred to as "basic image model") that is the basis for creating a shaded map, slope map, elevation map, or bird's-eye view map, to create an image with enhanced brightness. One of its features is that it creates a model for creating (hereinafter referred to as an "enhanced image model"). Figure 1(a) shows a topographical image drawn based on the basic image model (hereinafter simply referred to as "basic image"), and Fig. 1(b) shows a topographical image drawn based on the enhanced image model (hereinafter simply referred to as "basic image"). , simply referred to as "enhanced image"). Comparing Figures 1(a) and 1(b), we can see that the basic image allows for a more realistic three-dimensional understanding of the terrain (in a state similar to the human eye) due to the headlight effect than the basic image. I can understand.

Here, the basic image model 200 is composed of a plurality of small regions (pixels PX) obtained by dividing the target range, as shown in FIG. Further, each pixel PX constituting the basic image model 200 has at least plane position information (plane coordinates), or can also have height information (that is, three-dimensional coordinates) in addition to plane position information. Furthermore, each pixel PX of the basic image model 200 is given color information including brightness.

Originally, colors are perceived visually by humans and are subject to individual differences, but in recent years, colors have been modeled to be handled by computers. There are various methods for modeling colors, including RGB, which has the three basic colors of red, green, and blue; cyan, magenta, yellow; CMYK, which has the four basic colors of black (keycolor), and NCS and Ostwald color system, which have six basic colors of yellow, red, blue, green, black, and white, are known. The color information here refers to "values for specifying colors" defined by color modeling such as RGB, CMYK, NCS, and Ostwald color system. For example, when RGB is used, the color information for pure red is (255, 0, 0), the color information for pure green is (0, 255, 0), and the color information for pure blue is (0, 0). , 255).

Furthermore, the color information referred to here also includes a gray scale consisting only of brightness. Grayscale is a model that divides objects into multiple stages from white to black, and the "values that specify the degree of shading" defined by this model are grayscale values. For example, if there are 256 levels from white to black, white can be represented by a gray scale value of 255, and black can be represented by a gray scale value of 0. Of course, the gray scale can be expressed as a dimensionless range of 0 to 1, or as a percentage of 0 to 100%.

The emphasized image is an image in which the brightness is particularly emphasized among the color information possessed by each pixel PX of the basic image model, and the emphasized image model is a model for creating this emphasized image. More specifically, after setting a reference point (or reference plane) as a light source point or viewpoint, calculate the distance from this reference point or reference plane to each pixel PX (hereinafter referred to as "line-of-sight distance"), and then New color information (hereinafter referred to as "emphasis color information") is set by adjusting the brightness of the pixel PX of the basic image model according to the line-of-sight distance, and by adding the emphasis color information to each pixel PX. An enhanced image model is created. That is, the emphasized image model is constituted by each pixel PX of the basic image model (that is, each pixel PX constituting the emphasized image model and the basic image model is common). Note that the emphasis color information is set so that the shorter the line-of-sight distance, the brighter the color becomes.

2. Enhanced Image Model Creation System FIG. 3 is a block diagram showing the main configuration of the enhanced image model creation system 100 of the present invention. As shown in this figure, the enhanced image model creation system 100 includes a line-of-sight distance calculation means 101 and an emphasis color information setting means 102, and further includes a reference point moving means 103, a drawing means 104, a reference setting means 105, a display, etc. It can also be configured to include display means 106, basic image model storage means 107, and enhanced image model storage means 108.

The line-of-sight distance calculation means 101, emphasis color information setting means 102, reference point moving means 103, drawing means 104, and reference setting means 105 that constitute the emphasized image model creation system 100 can be manufactured as dedicated ones, or can be manufactured as general-purpose ones. Other computer equipment may also be used. This computer device can be configured by a personal computer (PC), a tablet PC such as an iPad (registered trademark), a mobile terminal including a smartphone, or the like. A computer device includes a processor such as a CPU, a memory such as a ROM or a RAM, and some devices further include input means such as a mouse and a keyboard, and a display. The display means 106 is preferably a display of this computer device.

Furthermore, the basic image model storage means 107 and the enhanced image model storage means 108 can be stored in a general-purpose computer, or can be constructed in a database server. ), or it can be a cloud server that stores it via the Internet (that is, wireless communication).

Hereinafter, the main processing of the enhanced image model creation system 100 of the present invention will be explained in detail with reference to FIG. FIG. 4 is a flow diagram showing the main processing flow of the enhanced image model creation system 100 of the present invention. In these flowcharts, the middle column shows the action to be performed, the left column shows what is required for the action, and the right column shows what results from the action.

First, a reference point is set using the reference setting means 105 (FIG. 3) (Step 101 in FIG. 4). For example, an operator can input a reference point using a pointing device such as a mouse or a keyboard. Note that the reference point 310 can be designed to have only one point set as shown in FIGS. 5 and 6, or can be set to two or three or more points as shown in FIG. can. Further, the reference point 310 is preferably set, for example, at a high position (that is, above) the topography targeted by the basic image model 200, and is therefore preferably set to be located in a three-dimensional space (having three-dimensional coordinates).

When the reference point 310 is set, the basic image model 200 is read out from the basic image model storage means 107 (FIG. 3) (Step 102 in FIG. 4), and the line of sight distance is calculated based on this basic image model 200 and the reference point 310. The means 101 (FIG. 3) calculates the "line of sight distance" (Step 103 in FIG. 4). This line-of-sight distance 400 is the distance from the reference point 310 to each pixel PX, and is particularly determined as the straight-line distance from the reference point 310 to the pixel PX. Therefore, the line-of-sight distance 400 is calculated by the number of pixels PX.

As mentioned above, the basic image model 200 can be composed of pixels PX having only plane position information (plane coordinates) (that is, without height information), or can be composed of pixels PX having three-dimensional coordinates. You can also do it. When using a basic image model 200 composed of pixels PX having only plane coordinates, as shown in FIG. ” and then the line-of-sight distance 400 can be calculated. Specifically, the line of sight, which is the straight-line distance from the reference point 310 to the pixel PX, is determined based on the three-dimensional coordinates that each pixel PX has and the reference height, and the three-dimensional coordinates that the reference point 310 has. Calculate the distance 400.

On the other hand, when using the basic image model 200 made up of pixels PX having three-dimensional coordinates, height information is given in advance to each pixel PX making up the basic image model 200, as shown in FIG. Therefore, the line-of-sight distance 400, which is the straight-line distance from the reference point 310 to the pixel PX, may be calculated based on the three-dimensional coordinates of each pixel PX and the three-dimensional coordinates of the reference point 310.

Furthermore, although it has been explained that two or more reference points 310 can be set, the line-of-sight distance 400 in this case is determined for each set reference point 310. For example, in the case shown in FIG. 7, two reference points 310, a reference point 311 and a reference point 312, are set, and focusing on one pixel PX, the line-of-sight distance 401 related to the reference point 311 is determined, and then the reference point The line of sight distance 402 related to 312 is calculated. In other words, when a plurality of reference points 310 are set, the line-of-sight distance 400 is determined by the product of the number of reference points 310 (two in FIG. 7) and the number of pixels PX (number of reference points x number of pixels). .

When the line-of-sight distance 400 for each pixel PX is calculated, the emphasis color information setting means 102 (FIG. 3) sets "emphasis color information" (Step 104 in FIG. 4). This emphasized color information is color information in which the brightness of each pixel PX of the basic image model 200 (hereinafter referred to as "basic brightness") is adjusted according to the line-of-sight distance 400, and the shorter the line-of-sight distance 400, the brighter it becomes. It is set so that the longer the line-of-sight distance 400, the darker the image becomes.

For example, the emphasis color information can also be calculated based on the brightness obtained by the following equation (1) (hereinafter referred to as "emphasis brightness"). Note that E _d in the formula is emphasized brightness, d is line-of-sight distance 400, F(d) is a "brightness coefficient" that is a function of line-of-sight distance 400, and E is basic brightness.
E _d =F(d)×E (1)
For example, if each pixel PX of the basic image model 200 is given a gray scale (0 to 255) as color information, the brightness coefficient F(d) is determined in the range of 0 to 1, and the line of sight distance 400 is short. It is preferable to set the brightness coefficient F(d) so that the brightness coefficient F(d) is calculated as a value closer to 1 as the line of sight distance 400 becomes longer, and the brightness coefficient F(d) is calculated as a value closer to 0 as the line of sight distance 400 becomes longer. In addition, considering that the target area (for example, the area illuminated by a light source) expands according to the line-of-sight distance 400, the brightness coefficient F(d) is calculated as the square of the line-of-sight distance 400, as shown in the following equation (2). It can also be a function that is inversely proportional to . Note that a in the formula (where a>0) is an arbitrary constant.
F(d)=a÷ ^d2 (2)

When two or more reference points 310 are set, that is, when two or more line-of-sight distances 400 are obtained for each pixel PX, emphasis color information may be set based on each line-of-sight distance 400. For example, the statistical values (average value, median value, mode, weighted average value, etc.) of multiple line-of-sight distances 400 are set as the representative line-of-sight distance 400 at that pixel PX, and the emphasis is based on this representative line-of-sight distance 400. Color information can be set.

When emphasized color information is set for each pixel PX, an emphasized image model is created by assigning this emphasized color information to each pixel PX (Step 105 in FIG. 4), and the emphasized image model storage means 108 (see FIG. 3). Then, the drawing means 104 (FIG. 3) displays the emphasized image on the display means 106 (FIG. 3) such as a display by drawing the emphasized image model according to the emphasized color information of each pixel PX (Step 106 in FIG. 4). . At this time, it is also possible to display the emphasized image while moving the reference point 310 using the reference setting means 105 (FIG. 3). Specifically, as shown in FIG. 8, as the reference point 310 moves (Step 107 in FIG. 8), the line-of-sight distance calculation means 101 calculates the line-of-sight distance 400 for each pixel PX, and the emphasized color information setting means 102 calculates the line-of-sight distance 400 for each pixel PX. Emphasis color information is set for each pixel PX, and the drawing means 104 (FIG. 3) draws to display the emphasis image. That is, by displaying the emphasized image every time the reference point 310 moves, the emphasized image is displayed as a moving image (frame-by-frame still image). Note that the reference setting means 105 may be designed to move the reference point 310 by the operator, or may be designed to move the reference point 310 according to a predetermined (or input) trajectory.

Although the case has been described so far in which the reference point 310 is set, the enhanced image model creation system 100 of the present invention can also set a reference plane instead of the reference point 310 (Step 101 in FIG. 4). When setting a reference plane, the line-of-sight distance 400 is determined as the shortest distance from the reference plane to each pixel PX. For example, in FIG. 9, the reference plane 310 is set horizontally, and each pixel PX is extended in the perpendicular direction (that is, the vertical direction) to the reference plane 320, and the length of the resulting line segment is determined as the line-of-sight distance 400. It will be done. Note that the basic image model 200 shown in FIG. 9 has only plane coordinates, and is given a predetermined "reference height" similarly to FIG. 5. On the other hand, when using a basic image model 200 composed of pixels PX having three-dimensional coordinates as shown in FIG. The line segment is then extended in the vertical direction (that is, the vertical direction), and the length of the line segment obtained as a result is determined as the line-of-sight distance 400.

When the line-of-sight distance 400 of each pixel PX is obtained (Step 103 in FIG. 4), emphasis color information is set for each pixel PX (Step 104 in FIG. 4), similar to setting the reference point 310, to create an emphasis image model. (Step 105 in FIG. 4), and a highlighted color image can be drawn (Step 106 in FIG. 4).

The enhanced image model creation system of the present invention can be used to more realistically view the topography of mountainous areas, and can also be used to view various topography such as urban areas and tourist spots.

100 Emphasized image model creation system of the present invention 101 Line of sight distance calculation means (of the emphasis image model creation system) 102 Emphasis color information setting means (of the emphasis image model creation system) 103 Reference point moving means (of the emphasis image model creation system) 104 Drawing means (of the emphasized image model creation system) 105 Standard setting means (of the emphasized image model creation system) 106 Display means (of the emphasized image model creation system) 107 Basic image model storage means (of the emphasized image model creation system) 108 (Emphasis Enhanced image model storage means (of the image model creation system) 200 Basic image model 310 Reference point 320 Reference plane 400 Line-of-sight distance PX pixels

Claims (5)

In a system that creates an enhanced image model using a basic image model composed of a plurality of pixels having planar position information,
Each pixel constituting the basic image model is given color information including brightness,
a line-of-sight distance calculation means that reads the basic image model and calculates a line-of-sight distance, which is a straight-line distance from two or more preset reference points to the pixel, for each pixel;
Emphasis color information setting means for setting emphasis color information for each pixel, the brightness of the color information being changed according to the line-of-sight distance;
The line-of-sight distance calculation means calculates the line-of-sight distance for each of the reference points for each pixel;
The emphasis color information setting means sets the emphasis color information so that the shorter the line-of-sight distance is, the brighter it becomes, and sets the emphasis color information for each pixel based on the line-of-sight distance regarding two or more of the reference points. Set,
creating the emphasized image model by assigning the emphasized color information to each of the pixels;
An enhanced image model creation system characterized by: Reference point moving means for moving the reference point;
Further comprising a drawing means for drawing an image in which the emphasized color information is output for each pixel,
The line-of-sight distance calculation means calculates the line-of-sight distance for each pixel as the reference point moves;
The emphasis color information setting means sets the emphasis color information for each pixel as the reference point moves;
The drawing means draws the image as the reference point moves.
2. The enhanced image model creation system according to claim 1. Each of the pixels constituting the basic image model has height information,
The line-of-sight distance calculation means calculates the line-of-sight distance based on planar position information and height information of the pixel.
3. The enhanced image model creation system according to claim 1 or claim 2. The emphasis color information setting means determines a brightness coefficient according to the line-of-sight distance, and sets the emphasis color information by multiplying the brightness by the brightness coefficient.
The enhanced image model creation system according to any one of claims 1 to 3, characterized in that: The emphasis color information setting means calculates the brightness coefficient according to the square of the line-of-sight distance.
5. The enhanced image model creation system according to claim 4.

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