Methods and systems for visualizing changes in monitored targets

Abstract

Visualize the changes in the monitoring target so that they can be easily grasped by monitors and the like. Provide a method and a system. 【Solution means】 The method for visualizing the changes in the monitoring target is to obtain the first three-dimensional point cloud data of the monitoring target at a first time (S1), and obtain the second three-dimensional point cloud data of the monitoring target at a second time different from the first time (S2), generate the first projection data of the first three-dimensional point cloud data onto a predetermined plane (S3), generate the second projection data of the second three-dimensional point cloud data onto the predetermined plane (S4), superimpose the first projection data and the second projection data to perform difference extraction, and generate difference data indicating the difference in the coordinate values in the direction perpendicular to the predetermined plane between the first projection data and the second projection data (S5), and display the difference data as an image (S6, S7).

Description

Technical Field

[0001] The present invention relates to a method and system for visualizing changes in a monitoring target.

Background Art

[0002] In Patent Document 1, a target installed on a slope such as a cliff is photographed by a plurality of displacement detection devices installed at different positions, and displacement information of the slope where the target is installed is detected using the obtained images. The technology is described.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above prior art, there is a possibility that changes occurring in a part of the slope, particularly changes in a part far from the target, cannot be detected. Since such changes can also be precursors to serious accidents such as collapses, it is desirable to make them easily understandable by monitors and the like. Note that such a demand is not limited to slopes such as cliffs, but is common to natural objects and artificial objects that require monitoring or for which it is desirable to monitor. \>

[0005] Therefore, an object of the present invention is to provide a method and system capable of visualizing changes in a monitoring target so that they can be easily understood by monitors and the like.

Means for Solving the Problems

[0006] ​​​​​​According to one aspect of the present invention, a method for visualizing changes in a monitored object is provided. The method includes a first step of acquiring first three-dimensional point cloud data of the monitored object at a first time, and , acquire second three-dimensional point cloud data of the monitored object at a second time different from the first time. The second step is to generate first projection data of the first three-dimensional point cloud data onto a predetermined plane. Furthermore, each point of the first projection data has coordinate values ​​in a direction perpendicular to the predetermined plane, and a third step The process generates second projection data of the second three-dimensional point cloud data onto the predetermined surface, and the process is described below. A fourth step in which each point of the projection data of 2 has coordinate values ​​in a direction perpendicular to the predetermined plane, and The first projection data and the second projection data are superimposed and the difference is extracted, and the first The difference in coordinate values ​​in the direction perpendicular to the predetermined plane between the projection data and the second projection data. A fifth step involves generating difference data showing the minutes, and a third step involves displaying the difference data as an image. It includes 6 steps.

[0007] According to another aspect of the present invention, a system for visualizing changes in a monitored object is provided. The system to be implemented includes a point cloud data acquisition device that acquires three-dimensional point cloud data, and a three-dimensional point cloud data The system includes a point cloud data processing device and a display device. The point cloud data processing device is a point cloud data processing device. The first three-dimensional point cloud of the monitored object, acquired by the point cloud data acquisition device at time 1. Generate first projection data of the data onto a predetermined plane, and a second time different from the first time. The second three-dimensional point cloud data of the monitored object acquired by the point cloud data acquisition device during the period A projection data generation unit that generates second projection data onto the predetermined surface, and the first projection data The first projection data and the second projection data are superimposed and the difference is extracted, and the first projection data and the previous A difference data generation unit that generates difference data indicating a difference in coordinate values in a direction perpendicular to the predetermined plane between the first projection data and the second projection data, and an image data generation unit that generates difference image data based on the difference data. The display device displays the difference image data. and an image data generation unit that generates difference image data based on the difference data. The display device displays the difference image data. and an image data generation unit that generates difference image data based on the difference data. The display device displays the difference image data.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a method and a system that can visualize changes in a monitoring target so that they can be easily grasped by a monitor or the like. According to the present invention, it is possible to provide a method and a system that can visualize changes in a monitoring target so that they can be easily grasped by a monitor or the like.

Brief Description of the Drawings

[0009] [Figure 1] It is a block diagram showing a schematic configuration of a visualization system according to an embodiment. [Figure 2] It is a functional block diagram of a point cloud data processing device that constitutes a visualization system. [Figure 3] It is a diagram for explaining an example of extraction (calculation) of a difference in coordinate values in a direction perpendicular to a predetermined plane between two projection data on the predetermined plane. [Figure 4] It is a flowchart showing an example of a process performed by a visualization system. [Figure 5] It is a diagram showing an example of three-dimensional point cloud data on the surface of a monitoring target (retaining wall) coordinate-converted into a local coordinate system. [Figure 6] It is a diagram showing an overview of XY-plane projection data of three-dimensional point cloud data on the surface of a monitoring target (retaining wall) shown in FIG. 5 onto the XY plane. [Figure 7] It is a diagram showing an overview of XZ-plane projection data of three-dimensional point cloud data on the surface of a monitoring target (retaining wall) shown in FIG. 5 onto the XZ plane. [Figure 8] It is a diagram showing an example of display of first difference image data based on Z coordinate value difference data indicating a difference in Z coordinate values. [Figure 9] It is a diagram showing an example of display of second difference image data based on Y coordinate value difference data indicating a difference in Y coordinate values. [Figure 10]It is a diagram showing an example of display of first difference enlarged image data based on enlarged Z coordinate value difference data. [Figure 11] It is a diagram showing an example of display of second difference enlarged image data based on enlarged Y coordinate value difference data. [Figure 12] It is a diagram showing an example of planar development data of three-dimensional point cloud data of the tunnel inner surface. [Figure 13] It is a diagram showing an example of display of difference image data based on Z coordinate value difference data indicating the difference in Z coordinate values. [Figure 14] It is a diagram showing an example of display of difference enlarged image data based on enlarged Z coordinate value difference data.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0011] FIG. 1 is a block diagram showing a schematic configuration of a visualization system 1 according to an embodiment of the present invention. The visualization system 1 according to the embodiment acquires three-dimensional point cloud data of a monitoring target and is configured to visualize the change (movement) of the monitoring target based on the acquired three-dimensional point cloud data. Thereby, it is possible for a monitor or the like to easily grasp the change (movement) of the monitoring target. The monitoring target is a natural object or artificial object that requires monitoring or is desirable to monitor. Although not particularly limited, the monitoring target may include a natural slope, an artificial slope, a retaining wall, a tunnel, and / or a bridge, etc. As shown in FIG. 1, the visualization system 1 includes a point cloud data acquisition device 3, a point cloud data processing device 5, and a display device 7. The point cloud data acquisition device 3 is, for example, a 3D laser scanner, and scans the monitoring target to acquire three-dimensional point cloud data of the monitoring target. The three-dimensional point cloud data of the monitoring target of the monitoring target

[0012] The point cloud data acquisition device 3 is, for example, a 3D laser scanner, and scans the monitoring target to acquire three-dimensional point cloud data of the monitoring target. The three-dimensional point cloud data of the monitoring target of the monitoring target This refers to the reflection points of the laser scan light in the monitored object (hereinafter simply referred to as "each point") Includes position data (three-dimensional coordinate values). In this embodiment, point cloud data acquisition device 3 Each point in the three-dimensional point cloud data of the monitored subject, acquired by the above method, is a three-dimensional coordinate with respect to a predetermined reference point. It has a reference value. The point cloud data acquisition device 3 is mainly fixedly installed on the ground. However, This is not the only way to use the point cloud data acquisition device 3, which can also acquire data from unmanned aerial vehicles (UAVs) and ground vehicles. It may also be mounted on a moving object.

[0013] The point cloud data processing device 5 receives the three monitored data acquired by the point cloud data acquisition device 3. The dimensional point cloud data is processed. The point cloud data processing device 5, for example, processes at least one process A sasser, at least one memory, a user interface, and a communication interface. It consists of a computer that has the following components, and the processor loads the program into memory. Each function is realized by executing the process. Figure 2 shows the functions of the point cloud data processing device 5. This is a block diagram. As shown in Figure 2, the point cloud data processing device 5 has the following functional units: Group data input unit 51, coordinate transformation unit 52, projection data generation unit 53, difference data generation unit It includes 54 and an image data generation unit 55.

[0014] The point cloud data input unit 51 receives the three points of the monitored object acquired by the point cloud data acquisition device 3. Dimensional point cloud data is input. In this embodiment, the point cloud data input unit 51 inputs point cloud data The three-dimensional point cloud of the monitored object, acquired by the acquisition device 3 at least two different times. Enter the data.

[0015] The coordinate transformation unit 52, if necessary, inputs the monitored data into the point cloud data input unit 51. The coordinate transformation is performed on the three-dimensional point cloud data. Specifically, the coordinate transformation unit 52 is the point cloud data input unit. The three-dimensional point cloud data of the monitored target input to 51 is localized for the monitored target. The coordinates are transformed into a coordinate system. This coordinate transformation results in each of the three-dimensional point cloud data of the monitored object. The point has coordinate values ​​(X coordinate value, Y coordinate value, Z coordinate value) in the local coordinate system. The local coordinate system can be arbitrarily set according to the monitored object. However, in the aforementioned local coordinate system, the X-axis represents the "width (left and right) direction" of the monitored object, and the Y-axis The first axis represents the "depth (front-to-back) direction" of the monitored object, and the second axis represents the "height (up and down) direction" of the monitored object. This may represent "direction". Furthermore, the three-dimensional point cloud data of the monitored object is transferred to the local coordinate system. The coordinate transformation unit 52 may be omitted if coordinate transformation is not necessary.

[0016] The projection data generation unit 53 receives the three-dimensional points of the monitored object input to the point cloud data input unit 51. The predetermined surface of the three-dimensional point cloud data of the monitored object, which has been coordinate-transformed by the group data or the coordinate transformation unit 52. The projection data is generated onto the (projection plane). The generated projection data is the three-dimensional object being monitored. Each point in the point cloud data is arranged in two dimensions on the predetermined plane, but the generated projection data Each point on the plane has coordinate values ​​in a direction perpendicular to the predetermined plane.

[0017] In this embodiment, the projection data generation unit 53 receives the coordinates transformed by the coordinate transformation unit 52. The three-dimensional point cloud data of the monitored object is orthorectified onto a predetermined plane, and at that time, multiple points on the predetermined plane If they overlap, the point with the largest coordinate value in the direction perpendicular to the predetermined plane among the multiple points ( In other words, by keeping the point closest to the viewer in the projection direction and deleting all other points, the correct Projected data is generated by eliminating data duplication caused by projection. The predetermined surface is a component Specifically, the XY plane (corresponding to the vertical plane), XZ plane (corresponding to the horizontal plane), and It is the bi / or YX plane (corresponding to the secondary projection plane).

[0018] Alternatively, the projection data generation unit 53 receives the monitored target data input to the point cloud data input unit 51. The three-dimensional point cloud data is unfolded and projected onto a plane (for example, a horizontal plane) (i.e., unfolded into a plane). Generate data.

[0019] The differential data generation unit 54 generates two corresponding projections generated by the projection data generation unit 53. The shadow data is superimposed and the difference is extracted, and the predetermined plane between the two projection data is perpendicular. The difference in coordinate values ​​in a perpendicular direction is extracted (calculated) and difference data representing that difference is generated.

[0020] In this embodiment, the difference data generation unit 54 generates a point cloud at a first time (for example, at the initial stage). Based on the first three-dimensional point cloud data of the monitored object acquired by the data acquisition device 3, The first projection data is generated, and a second time (for example, a predetermined time) different from the first time. (During the elapsed time) the three-dimensional point cloud data of the monitored object acquired by the point cloud data acquisition device 3 The second projection data generated based on this is superimposed and difference extraction is performed, and the first projection data This shows the difference in coordinate values ​​in the direction perpendicular to the predetermined plane between the data and the second projection data. Differential data is generated. The interval between the first time and the second time is the monitored data. It can be set arbitrarily according to the circumstances.

[0021] Here, referring to Figure 3, the difference data generation unit 54 generates two corresponding projection data (1st The difference in coordinate values ​​in the direction perpendicular to the predetermined plane between the projection data of the first projection data and the second projection data. An example of extraction (calculation) will be explained.

[0022] The difference data generation unit 54 first creates a triangular mesh using three adjacent points in the first projection data. By forming this, the first projection data is represented as a collection of multiple triangular meshes, and each three The average of the coordinate values ​​of the three points forming the corner mesh in the direction perpendicular to the predetermined plane is calculated for each triangular mesh. The coordinate values ​​are defined as being in a direction perpendicular to the predetermined plane.

[0023] Next, the difference data generation unit 54 generates a triangular mesh at three adjacent points in the second projection data. By forming a mesh, the second projection data is represented as a collection of multiple triangular meshes, and each The average of the coordinate values ​​of the three points forming the triangular mesh in the direction perpendicular to the predetermined plane is used for each triangular mesh. This is the coordinate value in the direction perpendicular to the predetermined plane.

[0024] Then, the difference data generation unit 54 superimposes the first projection data and the second projection data. Then, the difference in coordinate values ​​in the direction perpendicular to the predetermined plane between the corresponding triangular meshes is extracted (calculated). To release.

[0025] However, if, for example, the subject of monitoring changes between the first period and the second period, the first period The triangular mesh of the shadow data and the triangular mesh of the second projection data will not be exactly the same. In other words, as shown in Figure 3, the first projection data and the second projection data are superimposed. Sometimes the triangular mesh (solid line) of the second projection data is the same as the triangular mesh (broken) of the first projection data. The line may be misaligned. Therefore, the difference data generation unit 54 generates the second projection data The coordinate values ​​of the triangular mesh in the direction perpendicular to the predetermined plane, and the triangular mesh of the second projection data Each of at least one triangular mesh of the first projection data overlaps with at least a portion of it. The coordinate values ​​in the direction perpendicular to the predetermined plane, the triangular mesh of the second projection data and the first projection data Based on the degree of overlap of the data with each of the at least one triangular meshes, The difference in coordinate values ​​in the direction perpendicular to a given plane is calculated.

[0026] For example, the triangular mesh of the first projection data partially overlaps with the triangular mesh of the second projection data. If there are three meshes, the position of the triangular mesh of the second projection data in the direction perpendicular to the predetermined plane Let the reference value be "d", and perpendicular to the predetermined plane of each of the three triangular meshes of the first projection data. Let the coordinate values ​​in the perpendicular direction be "a", "b", and "c", and the triangular mesh of the second projection data and the The degree of overlap between the projection data of 1 and each of the three triangular meshes is defined as "α%" and "β%". If we set it to "%" and "γ%", the difference data generation unit 54 will be "(da) × α / 100 + (d- b) × β / 100 + (dc) × γ / 100 gives the coordinate value in the direction perpendicular to the predetermined plane. Calculate the difference.

[0027] Returning to Figure 2, the image data generation unit 55 outputs the difference generated by the difference data generation unit 54. Differential image data is generated based on the data. In this embodiment, the image data generation unit 55 The difference data generated by the difference data generation unit 54 is displayed on the predetermined surface by the display device 7. Image data for displaying an image color-coded according to the magnitude of the difference in coordinate values ​​in a straight direction. In other words, different color effects depending on the magnitude of the difference in coordinate values ​​in the direction perpendicular to the predetermined surface. Image data containing information is generated as differential image data. The image data generation unit 55 generates differential When image data is generated, the generated differential image data is output to the display device 7.

[0028] Furthermore, the image data generation unit 55 can, if necessary, receive instructions to enlarge the image from, for example, a supervisor. If given, the difference data generated by the difference data generation unit 54 is multiplied by a predetermined multiplier. The system calculates and generates magnified difference data, and then uses the generated magnified difference data to create differential magnified image data. In this embodiment, the image data generation unit 55 generates the differential data generation unit 54. The generated difference data is then displayed in 3D on the display device 7 from a viewpoint obliquely above the predetermined surface. Image data for enlarged display is generated as differential enlargement image data. When the adult unit 55 generates differential magnified image data, it displays the generated differential magnified image data. Output to location 7.

[0029] Returning to Figure 1, the display device 7 is composed of a liquid crystal display, an organic EL display, and the like. The display device 7 receives the difference image data from the image data generation unit 55 of the point cloud data processing device 5. When a value is entered, the differential image data is displayed. In other words, the display device 7 displays the differential data This is displayed as an image color-coded according to the magnitude of the difference in coordinate values ​​in the direction perpendicular to the predetermined surface. The display device 7 also receives differential augmentation from the image data generation unit 55 of the point cloud data processing device 5. When image data is input, the display device 7 displays the difference-enlarged image data. In other words, the display device 7 The difference data is displayed as an image that is three-dimensionally enlarged from a viewpoint obliquely above the predetermined surface. Display it.

[0030] Next, we will explain the visualization process of changes (movements) of the monitored target by Visualization System 1. Figure 4 This is a flowchart showing an example of the process performed by Visualization System 1.

[0031] In step S1, the point cloud data acquisition device 3 monitors during a first period (for example, the initial period). The first three-dimensional point cloud data of the object being viewed is acquired. Each point in the first three-dimensional point cloud data is a predetermined It has three-dimensional coordinate values ​​relative to a reference point.

[0032] In step S2, the point cloud data acquisition device 3 operates at a second time that is different from the first time. At the specified time (after a predetermined period of time has elapsed), the second three-dimensional point cloud data of the monitored object is acquired. Each point in the original point cloud data has a three-dimensional coordinate value relative to the aforementioned reference point.

[0033] In step S3, the point cloud data processing device 5 receives the first data from the point cloud data acquisition device 3. The first three-dimensional point cloud data of the monitored object, acquired at the time of the first monitoring object, is input, and the second Generates first projection data of 1 three-dimensional point cloud data onto a predetermined plane. Each of the first projection data The point has coordinate values ​​in a direction perpendicular to the predetermined plane.

[0034] Specifically, in step S3, the point cloud data processing device 5 interacts with the point cloud data acquisition device 3. The first three-dimensional point cloud data of the monitored subject acquired in the first period by the monitored subject The coordinates are transformed to the local coordinate system, and the coordinate-transformed first three-dimensional point cloud data of the monitored object is obtained. The data is orthographically projected onto a predetermined surface, and the data duplication resulting from the orthographic projection is eliminated to obtain the first projection. The data is generated. The predetermined plane is the XY plane, XZ plane, and / or Y plane of the local coordinate system. This is the Z-plane.

[0035] Alternatively, in step S3, the point cloud data processing device 5 will provide the point cloud data to the point cloud data acquisition device 3. Therefore, the first three-dimensional point cloud data of the monitored object acquired in the first period is unfolded and projected onto a plane. Then, the first projection data is generated. The plane is, for example, a horizontal plane.

[0036] In step S4, the point cloud data processing device 5 processes the point cloud data in the same manner as in step S3. The second three-dimensional point cloud data of the monitored object acquired at the second time by the data acquisition device 3. The first projection is projected onto the predetermined surface to generate second projection data. Each point in the second projection data is the first projection data. It has coordinate values ​​in a direction perpendicular to a given plane.

[0037] In step S5, the point cloud data processing device 5 processes the corresponding first projection data and the second It generates difference data from the projection data. Specifically, the point cloud data processing device 5 generates the corresponding The first projection data and the second projection data are overlaid and the difference is extracted, and the first projection data The difference in coordinate values ​​in the direction perpendicular to the predetermined plane between the first and second projection data. Generate data.

[0038] In step S6, the point cloud data processing device 5 processes the difference image data based on the difference data. Data is generated. The difference image data is the coordinate values ​​of the difference data in a direction perpendicular to the predetermined plane. This is image data for displaying an image color-coded according to the magnitude of the difference. The resulting differential image data is output to the display device 7.

[0039] In step S7, the display device 7 displays the difference output from the point cloud data processing device 5. Image data is input and the difference image data is displayed. That is, the display device 7 displays the difference The minute data is color-coded according to the magnitude of the difference in coordinate values ​​in the direction perpendicular to the predetermined plane, and Display it.

[0040] In step S8, the point cloud data processing device 5 receives an enlargement display instruction from a monitor or the like. Determine whether or not it has been done. If an enlargement instruction is given, proceed to step S9 and enlarge. If no display instruction is given, this flow will terminate.

[0041] In step S9, the point cloud data processing device 5 multiplies the difference data by a predetermined magnification. Then, expandable difference data is generated.

[0042] In step S10, the point cloud data processing device 5 performs a difference based on the magnified difference data. Enlarged image data is generated. The difference enlarged image data is obtained by applying the difference data to the predetermined surface. This is image data intended to be displayed as a three-dimensionally enlarged image from a viewpoint diagonally above. The generated difference-enlarged image data is output to the display device 7.

[0043] In step S11, the display device 7 receives the difference magnified image from the point cloud data processing device 5. The data is input and the difference magnified image data is displayed. That is, the display device 7 displays the difference The minute data is displayed as an image that is three-dimensionally enlarged from a viewpoint obliquely above the predetermined surface. Here, the display device 7 displays the difference enlarged image data instead of the difference image data. They may be displayed, or the difference enlarged image data may be displayed in addition to the difference image data. stomach.

[0044] Thus, the visualization system 1 according to the embodiment, at a first time, the first of the monitored objects Three-dimensional point cloud data is acquired, and at a second time different from the first time, the second monitoring target The three-dimensional point cloud data is acquired, and the acquired first three-dimensional point cloud data is projected onto a predetermined plane. Shadow data is generated, and the acquired second three-dimensional point cloud data is projected onto the predetermined surface. The system generates data. The visualization system 1 also uses the first projection data and the second projection data. The data is overlaid and differences are extracted, and the first projected data and the second projected data Difference data is generated showing the difference in coordinate values ​​in the direction perpendicular to the predetermined plane between and . The visualization system 1 then displays the difference data as an image. Specifically, visualization System 1 generates differential image data based on the differential data, and the differential data The image is displayed as a color-coded image, with the difference in coordinate values ​​in the direction perpendicular to a given plane varying accordingly.

[0045] The aforementioned difference data represents the changes that occurred on each part of the surface of the monitored object between the first period and the second period. Changes in a direction perpendicular to the surface, that is, changes in a "unidirectional" direction for each part of the surface being monitored (movement) This shows the difference data, and this difference data is displayed as an image. The statues are colored differently depending on the magnitude of the change (movement) in a "unidirectional" direction. That is, The displayed image shows the parts of the monitored object that have changed (moved) in "one direction". It is displayed in a different color from other parts that do not change (move), which usually make up the majority of the area. Therefore, by viewing the displayed image, monitors can detect changes in the monitored subject. Whether or not there was movement, and which part of the monitored object changed (moved) in what direction. It can be easily understood.

[0046] Furthermore, when an enlargement display instruction is given to the visualization system 1, the difference data will be determined The magnification is multiplied to generate magnified difference data, and the generated magnified difference data is displayed as an image. Specifically, the visualization system 1, based on the magnified difference data, generates a magnified difference image data. A table is generated, and the difference data is enlarged three-dimensionally from a viewpoint obliquely above the predetermined plane. The displayed image shows the parts where there was a change (movement) in "one direction". Because it is displayed in a three-dimensional, emphasized way, monitors can monitor by looking at the displayed image. It is possible to easily grasp the state of the part of the object that has changed (moved).

[0047] Furthermore, the predetermined surface onto which the first and second three-dimensional point cloud data of the monitored object are projected corresponds to the monitored object. By setting multiple parameters, monitors can monitor changes in multiple directions on various parts of the surface of the monitored object. (Movement) and, by extension, how and which part of the monitored object has changed (moved) make it easy to track movement. Furthermore, it becomes possible to understand the details.

[0048] Furthermore, for example, the first period is the start of monitoring, and the second period is repeated monitoring. By performing the first monitoring, second monitoring, third monitoring, etc. in the visual field, Based on the images they each generate, monitors can analyze changes (movements) in the monitored object in more detail. In addition to being able to grasp the situation, in some cases it can also predict changes (movements) in the monitored object. It will also become possible to do so.

[0049] Next, the present invention will be further explained by examples.

[0050] [First Embodiment] As the first embodiment, a visualization system when the monitoring target is a retaining wall (including a part of the retaining wall) Let me explain an example of operation of M1. In this case, the point cloud data acquisition device 3 operates at the first time and During the second stage, the retaining wall is scanned to obtain three-dimensional point cloud data of the retaining wall surface.

[0051] The point cloud data input unit 51 of the point cloud data processing device 5 receives data from the point cloud data acquisition device 3. Input the three-dimensional point cloud data of the surface of the retaining wall.

[0052] The coordinate transformation unit 52 of the point cloud data processing device 5 processes the three-dimensional data input to the point cloud data input unit 51. Point cloud data, i.e., three-dimensional points on the surface of the retaining wall acquired by the point cloud data acquisition device 3. The group data is transformed into a local coordinate system, such as the one shown in Figure 5, which is set up for retaining walls. This coordinate transformation allows each point in the three-dimensional point cloud data of the retaining wall surface to be in the local coordinate system. It will have coordinate values ​​(X coordinate value, Y coordinate value, Z coordinate value). Note that it is a local coordinate system. The X-axis represents the width (left-right) of the retaining wall, the Y-axis represents the depth (front-back) of the retaining wall, and the Z-axis represents the retaining wall. This represents the vertical (up and down) direction of the wall.

[0053] The projection data generation unit 53 of the point cloud data processing device 5 generates three-dimensional data of the surface of the retaining wall after coordinate transformation. The point cloud data is orthorectified into the XY plane to obtain XY plane projection data, and into the XZ plane to obtain XZ plane projection data. Shadow data and / or YZ plane projection data projected orthorectified onto the YZ plane are generated. Here, XY Each point in the surface projection data has a Z coordinate value, and each point in the XZ surface projection data has a Y coordinate value, and YZ Each point in the surface projection data has an X coordinate value. Note that Figure 6 shows the surface of the retaining wall shown in Figure 5. An overview of the XY plane projection data of the three-dimensional point cloud data is shown, and Figure 7 shows the retaining wall shown in Figure 5. An overview of the XZ plane projection data of the three-dimensional point cloud data of the surface is shown.

[0054] The difference data generation unit 54 of the point cloud data processing device 5 generates the difference in Z coordinate values ​​as difference data. Z coordinate difference data showing the difference in Z coordinate values, Y coordinate difference data showing the difference in Y coordinate values, and / or X coordinate Generate X-coordinate difference data showing the difference in the standard values.

[0055] The Z-coordinate difference data is the first three-dimensional point cloud data of the retaining wall surface acquired in the first period. The first XY plane projection data generated from and the second retaining wall surface acquired at the second time It is generated based on a second XY plane projection data generated from three-dimensional point cloud data. The level difference data is generated from the first three-dimensional point cloud data of the retaining wall surface acquired in the first period. The first XZ plane projection data is obtained, and the second three-dimensional data of the retaining wall surface is obtained at the second time. It is generated based on the second XZ plane projection data generated from the point cloud data. X coordinate value difference The minute data is generated from the first three-dimensional point cloud data of the retaining wall surface acquired in the first period. The first YZ plane projection data and the second three-dimensional point cloud data of the retaining wall surface acquired at the second time. It is generated based on the second YZ plane projection data generated from the first data.

[0056] The image data generation unit 55 of the point cloud data processing device 5 generates the Z coordinate value difference as differential image data. First difference image data based on minute data, second difference image data based on Y coordinate difference data A third differential image data is generated based on the data and / or the X coordinate difference data.

[0057] The first difference image data shows the Z coordinates that appeared on the surface of the retaining wall between the first and second time periods. This shows the difference in values ​​(change in the Z-axis direction) and the magnitude of the difference in Z-coordinate values ​​(amount of change in the Z-axis direction). This is image data for displaying in different colors according to the first. The second difference image data is the first This shows the difference in Y-coordinate values ​​(changes in the Y-axis direction) that occurred on the surface of the retaining wall between the first period and the second period. In addition, it is used to display the data in different colors according to the magnitude of the difference in Y coordinate values ​​(the amount of change in the Y axis direction). This is image data. The third difference image data shows the surface of the retaining wall between the first and second periods. This shows the difference in X coordinate values ​​that occurred on the surface (change in the X-axis direction), and the magnitude of the difference in X coordinate values. This is image data for color-coding display based on the amount of change in the X-axis direction.

[0058] The display device 7 displays the first difference generated by the image data generation unit 55 of the point cloud data processing device 5. Display the image data, the second differential image data, and / or the third differential image data.

[0059] Figure 8 shows an example of the display of the first difference image data by the display device 7, and Figure 8(a) shows the second difference image data. Figure 8(b) shows an example of displaying the first differential image data when the period is the nth monitoring time. An example of displaying the first differential image data when time point 2 is the (n+1)th monitoring time is shown below. Figure 8(c) shows the first differential image data when the second time period is the (n+2)th monitoring time. An example of the display is shown. Figure 9 is an example of the display of the second difference image data by the display device 7, and Figure 9(a Figure ) shows an example of displaying the second differential image data when the second time period is the nth monitoring time. 9(b) is a table of the second differential image data when the second time period is the (n+1)th monitoring time. As an example, Figure 9(c) shows the second difference plot when the second time period is the (n+2)th monitoring. An example of image data display is shown. Note that Figures 8 and 9 show an example of the display on the display device 7 (display image). Although shown in black and white, it is actually displayed in color.

[0060] By viewing the display images of the display device 7 shown in Figures 8 and 9, the monitors can determine the condition of the retaining wall. Changes (movements) in the Z-axis direction (vertical direction) and Y-axis direction (front-back direction) of "A section" on the surface. It is easy to grasp that something happened, and that the changes (movements) are continuing. Cut.

[0061] Furthermore, if an enlargement display instruction is given, the image data generation unit 55 of the point cloud data processing device 5 This is the magnified Z-coordinate difference data obtained by multiplying the Z-coordinate difference data by a predetermined magnification factor. The first difference-enlarged image data is obtained by multiplying the Y-coordinate difference data by a predetermined magnification factor. A second difference-enlarged image data based on the enlarged Y-coordinate difference data, and / or X-coordinate Based on the magnified X-coordinate value difference data obtained by multiplying the value difference data by a predetermined magnification factor, Generate the difference-enlarged image data for step 3.

[0062] The first difference-enlarged image data shows the Z-force that occurred on the surface of the retaining wall between the first and second time periods. The difference in coordinate values ​​(change in the Z-axis direction) is displayed in a three-dimensional, magnified view from an oblique upward perspective relative to the XY plane. This is image data for demonstration purposes. The second difference-enlarged image data compares the first and second time periods. The difference in Y coordinate values ​​(change in the Y-axis direction) that occurred on the surface of the retaining wall between the two points is measured diagonally upwards relative to the XZ plane. This is image data for displaying a three-dimensional enlarged view from a specific perspective. Third difference enlarged image data Ta is the difference in X-coordinate values ​​(in the X-axis direction) that occurred on the surface of the retaining wall between the first period and the second period. Image data for displaying changes in a three-dimensional, enlarged view from an oblique upward perspective relative to the YZ plane. be.

[0063] The display device 7 displays the first difference generated by the image data generation unit 55 of the point cloud data processing device 5. The enlarged image data, the second differential enlarged image data, and / or the third differential enlarged image data are displayed. To show.

[0064] Figure 10 shows an example of the display of the first difference-enlarged image data by the display device 7, and Figure 10(a) is The second time period is the nth monitoring time, and an example of displaying the first difference-enlarged image data is shown in Figure [Figure]. 10(b) is the first difference magnified image date when the second time period is the (n+1)th monitoring time. An example of the display of time is shown in Figure 10(c), where the second time is the (n+2)th monitoring time. An example of displaying the difference-enlarged image data from step 1 is shown. Figure 11 shows the second difference-enlarged image displayed by the display device 7. This is an example of data display, and Figure 11(a) shows the second time when the second period is the nth monitoring time. An example of displaying difference-enlarged image data is shown in Figure 11(b), where the second period is the (n+1)th monitoring. Figure 11(c) shows an example of displaying the second difference magnified image data at a certain time. An example of displaying the second difference-enlarged image data at the (n+2)th monitoring time is shown. In Figures 10 and 11, examples of displays (display images) of the display device 7 are shown in black and white, In reality, it's displayed in color.

[0065] By viewing the display images of the display device 7 shown in Figures 10 and 11, the monitors and others can see the display images of the display device 7. To easily and thoroughly understand the condition of "Section A" on the surface of the retaining wall where a change (movement) has occurred. It is possible.

[0066] [Second Example] As a second embodiment, the operation of the visualization system 1 when the monitored object is a tunnel (inside). Let's explain an example. In this case, the point cloud data acquisition device 3 performs the first and second measurements. The tunnel's interior is scanned to obtain three-dimensional point cloud data of the tunnel's interior.

[0067] The point cloud data input unit 51 of the point cloud data processing device 5 receives data from the point cloud data acquisition device 3. Input the three-dimensional point cloud data of the tunnel's interior surface.

[0068] The projection data generation unit 53 of the point cloud data processing device 5 receives the data input to the point cloud data input unit 51. Three-dimensional point cloud data, that is, the inner surface of the tunnel acquired by the point cloud data acquisition device 3. Three-dimensional point cloud data is unfolded and projected onto a horizontal plane (XY plane) to obtain projected data. Generate surface unfolded data. Here, each point in the unfolded data is perpendicular to the horizontal plane (XY plane). It has a directional coordinate value (Z coordinate value). Figure 12 shows the three-dimensional point cloud data of the tunnel interior. An example of the planar unfolding data for the object is shown.

[0069] The difference data generation unit 54 of the point cloud data processing device 5 generates the difference data inside the tunnel acquired in the first period. The first planar unfolded data of the first three-dimensional point cloud data of the surface, and the tunnel acquired at the second time. Based on the second planar unfolded data of the second three-dimensional point cloud data of the inner surface, the difference in Z coordinate values ​​is calculated. Generate the Z-coordinate difference data shown.

[0070] The image data generation unit 55 of the point cloud data processing device 5 performs a difference based on the Z coordinate value difference data. Generate image data. The differential image data is generated between the first and second time periods within the tunnel. This shows the difference in Z coordinate values ​​(change in the Z axis direction) that occurred on the surface, as well as the magnitude of the difference in Z coordinate values. This is image data for color-coding display according to the amount of change in the Z-axis direction. This corresponds to the normal direction of the tunnel's inner surface.

[0071] The display device 7 displays the difference image data generated by the image data generation unit 55 of the point cloud data processing device 5. The data is displayed. Figure 13 shows an example of the display of differential image data by the display device 7, and Figure 13(a Figure 13 shows an example of displaying differential image data when the second period is the nth monitoring time. b) shows an example of displaying differential image data when the second time period is the (n+1)th monitoring time. Figure 13(c) shows a table of differential image data when the second time period is the (n+2)th monitoring time. An example is shown. Note that in Figure 13, an example of the display (display image) of the display device 7 is shown in black and white. However, it is actually displayed in color.

[0072] By viewing the display image of the display device 7 shown in Figure 13, monitors can see inside the tunnel. There was a change (movement) in the Z-axis direction (normal direction to the inner surface of the tunnel) in the "B" part of the surface, The change (movement) of the "part" has almost stopped, and the "C part" now moves in the Z-axis direction (tunnel). It is easy to grasp when changes (movements) occur in the normal direction of the inner surface.

[0073] Furthermore, when an enlarged display instruction is given to the image data generation unit 55 of the point cloud data processing device 5, In addition, the Z-coordinate difference data is multiplied by a predetermined magnification to obtain the enlarged Z-coordinate difference data. The differential augmented image data is generated based on the first time period and the second time period. The difference in Z coordinate values ​​(changes in the Z-axis direction) that occurred on the inner surface of the tunnel between periods is measured obliquely with respect to the XY plane. This is image data intended for three-dimensional, enlarged display from a top-down perspective.

[0074] The display device 7 displays the difference magnified image generated by the image data generation unit 55 of the point cloud data processing device 5. Display image data. Figure 14 shows an example of displaying differential image data by the display device 7. (a) is the difference-enlarged image data (part B) when the second period is the (n+2)th monitoring time. An example of the display is shown, and Figure 14(b) shows the difference when the second time period is the (n+2)th monitoring time. An example of the display of the enlarged image data (part C) is shown. Note that in Figure 14, an example of the display of the display device 7 is shown. The displayed image is shown in black and white, but it is actually in color.

[0075] By viewing the display image of the display device 7 shown in Figure 14, monitors can see inside the tunnel. A rectangular bulge has formed in "section B" of the surface, and a rectangular bulge has formed in "section C" of the inner surface of the tunnel. It is easy to see that a depression of this shape has occurred.

[0076] The embodiments and examples of the present invention have been described above, but the present invention is not limited to the above embodiments and examples. The invention is not limited to the examples provided, and can be appropriately modified and altered based on the technical concept of the present invention. That is certainly true. [Explanation of symbols]

[0077] 1…Visualization system, 3…Point cloud data acquisition device, 5…Point cloud data processing device, 7…Display device 51...Point cloud data input unit, 52...Coordinate transformation unit, 53...Projection data generation unit, 54...Difference Data generation unit, 55...Image data generation unit

Claims

1. A method for visualizing changes in the monitored target, The first step is to acquire the first three-dimensional point cloud data of the monitored object in the first period, The second three-dimensional point cloud data of the monitored object is acquired at a second time, different from the first time. The second step is to do, First projection data onto a predetermined plane is generated from the first three-dimensional point cloud data, and the first projection A third step in which each point of the data has coordinate values ​​in a direction perpendicular to the predetermined plane, The second projection data of the second three-dimensional point cloud data onto the predetermined surface is generated, and the second A fourth step in which each point of the projection data has coordinate values ​​in a direction perpendicular to the predetermined plane, The first projection data and the second projection data are superimposed and the difference is extracted, Coordinates in a direction perpendicular to the predetermined plane between the first projection data and the second projection data. The fifth step involves generating difference data that shows the difference in values, The sixth step is to display the aforementioned difference data as an image, Methods that include...

2. The sixth step involves the difference data being color-coded according to the magnitude of the difference and The method according to claim 1, comprising displaying the information.

3. The sixth step involves viewing the difference data in three dimensions from a viewpoint obliquely above the predetermined plane. The method according to claim 1, which includes displaying the image as an enlarged image.

4. The third step is to transfer the first three-dimensional point cloud data to the local coordinate system for the monitored object. To perform a coordinate transformation on the first three-dimensional point cloud data that has undergone the coordinate transformation, and to perform a coordinate transformation on the local coordinate The data generated by orthorectifying the XY, XZ, and / or YZ planes of the standard system is obtained by orthorectifying the data. This includes eliminating duplicate data and generating the first projection data, The fourth step is to transform the second three-dimensional point cloud data into the local coordinate system. and the coordinate-transformed second three-dimensional point cloud data to the XY plane of the local coordinate system. , orthorectify the XZ plane and / or YZ plane, and eliminate the data duplication resulting from the orthorectification. This includes dividing to generate a second projection data, The method according to claim 1.

5. The third step involves unfolding and projecting the first three-dimensional point cloud data onto a plane to obtain the first projection data. This includes generating data, The fourth step involves unfolding and projecting the second three-dimensional point cloud data onto a plane to obtain the second projection data. Including generating data, The method according to claim 1.

6. The fifth step described above is: By forming a triangular mesh at three adjacent points in the first projection data, the previous The projection data in the first description is represented by a collection of multiple triangular meshes, and each triangular mesh is composed of The average of the coordinate values ​​of the three points perpendicular to the predetermined plane is taken in the direction perpendicular to the predetermined plane of each triangular mesh. To use the coordinate values ​​of the direction, By forming a triangular mesh at three adjacent points in the second projection data, the previous The projection data described in the second section is represented by a collection of multiple triangular meshes, and the three triangular meshes are composed of 3 The average of the coordinate values ​​of the point in the direction perpendicular to the predetermined plane is calculated for each triangular mesh in the direction perpendicular to the predetermined plane. The coordinate values ​​are to be used, The coordinate values ​​of the triangular mesh of the second projection data in the direction perpendicular to the predetermined plane, and the second At least a portion of the triangular mesh of the projection data overlaps with at least the first projection data. The coordinate values ​​of each of the two triangular meshes in a direction perpendicular to the predetermined plane, and the second projection The triangular mesh of the data and the at least one triangular mesh of the first projection data The difference is calculated based on the degree of overlap with each other, and the difference data is generated. and, The method according to claim 1, including the method described in claim 1.

7. A system that visualizes changes in the monitored target, A point cloud data acquisition device that acquires three-dimensional point cloud data, and a point cloud that processes the three-dimensional point cloud data. A data processing device and a display device are included. The point cloud data processing device is The first tertiary data of the monitored object acquired by the point cloud data acquisition device during the first period Generate first projection data of the original point cloud data onto a predetermined plane, and a different time from the first time. The second three-dimensional point cloud of the monitored object, acquired by the point cloud data acquisition device at time 2. A projection data generation unit that generates second projection data of the data onto the predetermined surface, The first projection data and the second projection data are superimposed and the difference is extracted. The position between the first projection data and the second projection data in a direction perpendicular to the predetermined plane. A difference data generation unit that generates difference data showing the difference in standard values, An image data generation unit that generates differential image data based on the differential data, Includes, The display device displays the differential image data. system.

8. The difference image data is colored according to the size of the difference by the display device. The system according to claim 7, wherein the image data is for displaying as a divided image.

9. The image data generation unit multiplies the difference data by a predetermined magnification to obtain an enlarged difference data Based on the data, difference-enlarged image data is generated. The display device displays the difference enlargement image data in place of or in addition to the difference image data. To show, The system according to claim 7.

10. The aforementioned difference-enlarged image data is obtained when the display device displays the difference data at an oblique angle to the predetermined plane. The system described in claim 9 is image data for displaying a three-dimensionally enlarged view from above. Tem.

11. The point cloud data processing device processes the first three-dimensional point cloud data and the second three-dimensional point cloud data. The system further includes a coordinate transformation unit that transforms the data into a local coordinate system for the monitored object, The projection data generation unit transforms the coordinates of the first three-dimensional point cloud data and processes it locally Project orthographically onto the XY plane, XZ plane, and / or YZ plane of the coordinate system, and the resulting digits The first projection data is generated by eliminating duplicate data, and the second three-dimensional data is obtained by coordinate transformation. The point cloud data is orthorectified onto the XY plane, XZ plane, and / or YZ plane of the local coordinate system, and To generate a second projection, eliminate the data duplication caused by orthographic projection. The system according to claim 7.

12. The projection data generation unit unfolds and projects the first three-dimensional point cloud data onto a plane to generate the first projection Shadow data is generated, and the second three-dimensional point cloud data is unfolded and projected onto a plane to obtain the second projection data. The system according to claim 7 for generating data.

13. The aforementioned differential data generation unit, By forming a triangular mesh at three adjacent points in the first projection data, the previous The projection data in the first section is represented by a collection of numerous triangular meshes, and each triangular mesh The average of the coordinate values ​​of the three points constituting the predetermined plane in the direction perpendicular to the predetermined plane of each triangular mesh The coordinate values ​​are taken as the direction perpendicular to the direction. By forming a triangular mesh at three adjacent points in the second projection data, the previous The second projection data is represented by a collection of numerous triangular meshes, and each triangular mesh The average of the coordinate values ​​of the three points constituting the predetermined plane in the direction perpendicular to the predetermined plane of each triangular mesh The coordinate values ​​are taken as the direction perpendicular to the direction. The coordinate values ​​of the triangular mesh of the second projection data in the direction perpendicular to the predetermined plane, and the second At least a portion of the triangular mesh of the projection data overlaps with at least the first projection data. The coordinate values ​​of each of the two triangular meshes in a direction perpendicular to the predetermined plane, and the second projection The triangular mesh of the data and the at least one triangular mesh of the first projection data The difference is calculated based on the degree of overlap with each other, and the difference data is generated. The system according to claim 7.

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