JP7152986B2 - Stone restoration position identification method and stone restoration position identification device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method and apparatus for identifying a restoration position of a collapsed stone in a stone wall.

Many of the stone walls of castles, temples, and shrines are several hundred years old and have deteriorated. Such stone walls have collapsed due to natural disasters such as earthquakes and typhoons, and there is a need to restore the collapsed stone walls. In particular, when a stone wall designated as a national historic site collapses, it is required to restore the stone wall to its original state before the collapse in order to protect its cultural value.

The shapes of the stone materials used for stone walls are different. In order to restore a collapsed stone wall accurately, it is necessary to individually specify the restoration position of the stone material in the collapsed stone wall. As a method for identifying the restoration position, Non-Patent Document 1 discloses a method using an image processing technique.

In Non-Patent Document 1, the image of the stone wall taken before the collapse and the image of the stone taken after the collapse are compared based on the brightness of the stone in the image, and the position of the stone in the stone wall before the collapse is determined. A method of identifying is disclosed.

Fujitsu Ltd. press release, "Demonstration experiment of image processing technology to identify stone wall stone position before collapse at Kumamoto Castle completed", [online], March 11, 2019, [searched March 25, 2019] , Internet (URL: http://pr.fujitsu.com/jp/news/2019/03/11-1.html)

In the method disclosed in Non-Patent Document 1, images are matched based on the brightness of stone materials. For this reason, when multiple stones in a stone wall are quarried from the same production area and have approximately the same brightness, it is difficult to identify the position of the stone in the stone wall before it collapsed, and the restoration position of the stone can be accurately determined. cannot be specified. In addition, even if the unevenness and contour of the stone are extracted as feature points, it is difficult to match when the surface of the stone is smooth or when the contours are similar. I can't

An object of the present invention is to specify the restoration position of the stone with high accuracy.

The present invention is a stone material restoration position identifying method for identifying the restoration position of a collapsed stone material in a stone wall. Using the image of the collapsed stone, the area of the exposed surface of the stone wall in the collapsed stone is calculated by image processing, and the area calculated using the image of the stone wall before the collapse and the image of the collapsed stone The restoration position of the collapsed stone material is specified by collating the calculated area.

Further, the present invention is a stone material restoration position identifying device for identifying the restoration position of a collapsed stone material in a stone wall. a post-collapse exposed area calculation unit that calculates, by image processing, the area of the surface assumed to be the stone wall exposed surface in the collapsed stone material using the image of the collapsed stone material; and a post-collapse exposed area calculation unit that calculates the exposed area before the collapse. with the area calculated by the post-collapse exposed area calculation unit to identify the restored position of the collapsed stone.

ADVANTAGE OF THE INVENTION According to this invention, the restoration position of a stone can be pinpointed with sufficient accuracy.

1 is a block diagram of a stone restoration position specifying device according to an embodiment of the present invention; FIG. It is a flowchart figure of the stone restoration position identification method which concerns on embodiment of this invention. FIG. 5 is a diagram showing an example of the outline of the exposed surface of the stone wall for each stone detected using the image of the stone wall before it collapsed; It is a figure which shows an example of the image of a collapsed stone material. FIG. 11 is a diagram showing an example of an image of a collapsed stone that has undergone face correction.

Hereinafter, a stone material restoration position identification method and a stone material restoration position identification device 100 according to an embodiment of the present invention will be described with reference to the drawings.

When the stone walls of castles, temples, and shrines that are designated as national historic sites, etc., collapse, it is required to restore the stone walls to their original state before they collapsed in order to protect their cultural value. Since the shapes of stone materials used for stone walls differ from one another, in order to restore a collapsed stone wall accurately, the restoration position of the stone materials (hereinafter referred to as "collapsed stone materials") in the collapsed stone wall must be specified individually. There is a need.

As a method of identifying the restoration position of the collapsed stone, it is conceivable to analyze the characteristics of the stone such as brightness, unevenness and outline, and compare these characteristics before and after the collapse. However, there are cases where the brightness of the stones in a stone wall is almost the same because they are quarried from the same place of production. I can't. In addition, when the surface of the stone is smooth or when the contours of the stone are similar, it is not possible to precisely specify the restoration position of the stone even if the unevenness or contour of the stone is collated before and after the collapse.

The stone restoration position specifying method according to the present embodiment collates the area of the exposed stone wall surface for each of the plurality of stones in the stone wall before the collapse with the area of the surface assumed to be the exposed stone wall surface in the collapsed stone wall. Therefore, the restoration position of the collapsed stone material is narrowed down according to the area of the stone wall exposed surface from among the plurality of stone materials of the stone wall before the collapse. Therefore, even when the brightness of a plurality of stone materials in the stone wall is substantially the same, the surface of the stone materials is smooth, or the contours of the stone materials are similar, the restoration positions of the stone materials can be specified with high accuracy.

The term “exposed face of the stone wall” means the face of the stone material that is exposed when the stone wall is constructed by piling up the stone materials. In addition, hereinafter, the area of the stone wall exposed surface for each of the plurality of stones in the stone wall before the collapse is also referred to as "pre-collapse exposed area", and the area of the surface assumed to be the stone wall exposed surface in the collapsed stone is "post-collapse exposed area". ” is also called.

A stone material restoration position identification device 100 according to the present embodiment is used for a stone material restoration position identification method. The configuration of the stone restoration position specifying device 100 will be specifically described below.

The stone restoration position specifying device 100 includes a microcomputer 10 . The microcomputer 10 includes a CPU (Central Processing Unit) that executes control programs and the like, a ROM (Read-Only Memory) that stores control programs and the like executed by the CPU, and a RAM (Random Access Memory), and performs arithmetic processing. The number of microcomputers 10 may be one or plural.

FIG. 1 is a block diagram of a stone restoration position specifying device 100. As shown in FIG. As shown in FIG. 1, the microcomputer 10 includes a pre-collapse exposed area calculator 11 that calculates the pre-collapse exposed area by image processing using the image of the stone wall before the collapse, and a pre-collapse exposed area calculation unit 11 that calculates the exposed area before the collapse using the image of the collapsed stone material. A post-collapse exposed area calculation unit 12 that calculates the post-collapse exposed area by image processing, and a specifying unit 13 that specifies the restored position of the collapsed stone by comparing the pre-collapse exposed area and the post-collapse exposed area. . The pre-collapse exposed area calculation unit 11, the post-collapse exposed area calculation unit 12, and the identification unit 13 are functions of the microcomputer 10 as virtual units.

FIG. 2 is a flow chart diagram of the method for identifying the stone restoration position. Steps S101 to S104 are pre-collapse exposed area calculation processing performed by the pre-collapse exposed area calculation unit 11, and steps S201 to S204 are post-collapse exposed area calculation processing performed by the post-collapse exposed area calculation unit 12. Steps S301 and S302 are stone material restoration position specifying processing performed by the specifying unit 13 .

First, the pre-collapse exposed area calculation processing (steps S101 to S104) will be described in detail.

In the pre-collapse exposed area calculation process, an image of the stone wall before the collapse is used. As shown in FIG. 1, the image of the stone wall before the collapse is a photograph taken before the collapse. A photograph is taken into the microcomputer 10 as image data by using the scanner 20 . The photograph used may be, for example, a photograph taken by a tourist, or a photograph taken by a restoration contractor when there is a plan to restore a stone wall and the restoration contractor has taken photographs of the stone wall in advance. There may be. If the stone wall before the collapse is photographed using a digital device and the image data remains, the image data may be loaded into the microcomputer 10 without using the scanner 20 .

As shown in FIG. 2, in step S101, the captured image is subjected to image processing to detect the outline of the exposed surface of the stone wall for each stone. When detecting the contour, for example, the brightness of the pixels is used. The detected contours can be displayed on monitor 30 (see FIG. 1).

In step S102, an ID (hereinafter also referred to as "pre-collapse ID") is given to each stone based on the detected contour. The pre-collapse ID assigned to each stone can be displayed on the monitor 30 together with the detected contour. FIG. 3 is an example of an image displayed on the monitor 30, showing a state in which a part of the detected contour and the assigned pre-collapse ID are displayed.

In step S103, the pre-collapse exposed area is calculated based on the detected contour. Specifically, the area of the stone wall exposed surface on the image of the stone wall before the collapse is calculated, and the exposed area before the collapse is calculated by using the calculated area on the image and the reduction ratio of the image. The reduction ratio of the image is calculated in advance by using a reference object (not shown) captured in the photograph and input to the microcomputer 10 .

The reference object is, for example, a display board installed near the stone wall, from which the dimensions can be grasped. If a reference object whose dimensions can be grasped is included in the photograph, the reduction ratio of the image can be calculated from this reference object. Moreover, when a part of the stone wall remains without collapsing, the stone material in the remaining stone wall may be used as the reference object. Specifically, in the case where a region C surrounded by a dashed line in the stone wall shown in FIG.

In step S104, the calculated pre-collapse exposed area is stored together with the pre-collapse ID in a storage unit (not shown) to create a database including the pre-collapse exposed area. With the above, the pre-collapse exposed area calculation process is completed.

Next, the post-collapse exposed area calculation processing (steps S201 to S204) will be described in detail.

In the post-collapse exposed area calculation process, an image of the collapsed stone material is used. An image of the collapsed stone is obtained by photographing the collapsed stone using a camera 40 (see FIG. 1). A still image may be taken for each collapsed stone and the said still image may be used as an image of the collapsed stone, or a video may be taken so as to show multiple collapsed stones in order, and a still image cut from the video may be used as the image of the collapsed stone. may be used. FIG. 4 is an example of an image of a collapsed stone.

When photographing the collapsed stone, an ID different from the pre-collapse ID (hereinafter also referred to as "post-collapse ID") is assigned to each collapsed stone, and the collapsed stone is photographed so that the post-collapse ID can be recognized. For example, a tape 51 describing the post-collapse ID is attached to the post-collapse stone, and the tape 51 and the collapsed stone are photographed. The post-collapse ID is taken into the microcomputer 10 together with the image of the collapsed stone material.

Also, when photographing the collapsed stone, the surface assumed to be the exposed surface of the stone wall in the collapsed stone is photographed. Whether or not the surface is an exposed stone wall is determined by the operator based on, for example, the way moss grows, the sunburned condition, or the weathered condition. In other words, compared to the non-exposed surface of the stone wall, the exposed surface of the stone wall is exposed to sunlight, wind and rain for a long period of time, so it is covered with moss, sunburnt, and weathered. Therefore, it is possible to determine whether or not the stone wall is exposed by looking at how the moss grows, the sunburned state, or the weathered state.

If the surface assumed to be the exposed surface of the stone wall is not photographed from the front but obliquely, the area of the surface assumed to be the exposed surface of the stone wall cannot be accurately calculated on the image. Therefore, the grid-like scale 52 is placed on the surface assumed to be the exposed stone wall so that the image obtained by photographing can be corrected by image processing as if the surface assumed to be the exposed stone wall was photographed from the front. Take a picture with it on.

When photographing the collapsed stone with the post-collapse ID tape 51 attached to the collapsed stone and the grid-like scale 52 applied to the collapsed stone, the collapsed stone with the tape 51 attached is arranged, and then It is preferable to photograph a moving image by sequentially applying the scale 52 to the collapsed stone material and moving the camera 40 . In this case, it is possible to photograph the collapsed stone material smoothly and speedily compared to the case of individually photographing still images of the fallen stone material.

Using the image of the collapsed stone photographed as described above, in the post-collapse exposed area calculation process, a database including the post-collapse exposed area is created.

As shown in FIG. 2, in step S201, image processing is performed on the image of the collapsed stone that has been photographed with the post-collapse ID assigned, and orientation correction is performed. Specifically, the image photographed as shown in FIG. 4 is expanded and contracted in the vertical and horizontal directions so that the peripheral edge 52a of the scale 52 is corrected to coincide with the edge PE of the image as shown in FIG. do. As a result, the image captured using the camera 40 (see FIG. 1) is corrected as if the surface assumed to be the exposed surface of the stone wall was captured from the front.

In step S202, the corrected image is used to detect the outline of the face assumed to be the exposed face of the stone wall in the collapsed stone. When detecting the contour, for example, the brightness of the pixels is used.

In step S203, the post-collapse exposed area is calculated based on the detected contour. Specifically, the area on the image of the surface assumed to be the exposed surface of the stone wall is calculated, and the exposed area after the collapse is calculated by using the calculated area on the image and the reduction ratio of the image. The image reduction ratio is calculated in advance using the scale 52 and input to the microcomputer 10 .

In step S201, since the image of the collapsed stone material has been subjected to face correction, it is possible to accurately calculate the area of the surface assumed to be the exposed surface of the stone wall on the image. Therefore, the post-collapse exposed area can be calculated accurately.

In step S204, the calculated post-collapse exposed area is stored in a storage unit (not shown) together with the post-collapse ID, and a database including the post-collapse exposed area is created. With the above, the post-collapse exposed area calculation processing ends.

Next, the stone restoration position specifying process (steps S301 and S302) will be described in detail.

In step S301, the calculated pre-collapse exposed area and the calculated post-collapse exposed area are collated, and the corresponding pre-collapse ID and post-collapse ID are linked. Specifically, by comparing a database containing the exposed area before the collapse and a database containing the exposed area after the collapse, a pre-collapse ID and a post-collapse ID in which the exposed area before the collapse and the exposed area after the collapse substantially match are obtained. connect with

Whether or not the areas substantially match is determined by whether or not the ratio of the post-collapse exposed area to the pre-collapse exposed area is within a predetermined reference range.

The reference range is preferably set in consideration of contour detection errors in steps S101 and S202. For example, the reference range can be set to a range of 95% or more and 105% or less.

Also, when the stone wall collapses, the stone may be chipped, and in this case, the exposed surface of the stone wall becomes smaller than before the collapse. Therefore, the central value of the reference range may be set to be smaller than "100%". For example, the reference range may be set to a range of 92% or more and 103% or less.

In step S302, the restoration position of the collapsed stone material is identified based on the linked pre-collapse ID and post-collapse ID. As shown in FIG. 3, since a pre-collapse ID is assigned to each stone in the stone wall before the collapse, the position of the stone with the pre-collapse ID linked to the post-collapse ID is confirmed on the image of the stone wall before the collapse. Thus, the restoration position of the collapsed stone can be identified. Alternatively, the post-collapse ID linked to the pre-collapse ID may be displayed on the image of the stone wall before the collapse to specify the restoration position of the collapsed stone material.

With the above, the stone material restoration position specifying process ends.

The area of the exposed surface of the stone wall is the same even if the exposed surface of the stone wall is turned upside down. Therefore, it is possible to compare the areas without specifying the top and bottom of the collapsed stone. Therefore, it is possible to easily specify the restoration position of the collapsed stone.

Although a detailed explanation is omitted, when multiple pre-collapse IDs are associated with one post-collapse ID as a result of matching the pre-collapse area and the post-collapse area, that is, when the pre-collapse ID cannot be narrowed down. , by comparing contours, dents, cracks, scratches, traces of moss, etc. between the collapsed stone and the narrowed-down pre-collapse ID stones, it is possible to specify the restored position of the collapsed stone.

According to the above embodiment, the following operational effects are obtained.

The stone restoration position specifying method and stone restoration position specifying device 100 collates the area calculated using the image of the stone wall before the collapse with the area calculated using the image of the collapsed stone. Therefore, the restoration position of the collapsed stone material is narrowed down according to the area of the stone wall exposed surface from among the plurality of stone materials in the image of the stone wall before the collapse. Therefore, even when the brightness of a plurality of stone materials in the stone wall is substantially the same, the surface of the stone materials is smooth, or the contours of the stone materials are similar, the restoration positions of the stone materials can be specified with high accuracy.

In addition, in the stone restoration position specifying method and stone restoration position specifying device 100, an image of the collapsed stone material photographed with the grid-shaped scale 52 applied to the collapsed stone material is acquired, and the acquired image is displayed based on the scale 52. The area is calculated using the image of the collapsed stone material after correcting the correct orientation. Therefore, it is possible to accurately calculate the area of the surface assumed to be the stone wall exposed surface. Therefore, the restoration position of the stone can be identified with higher accuracy.

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of application examples of the present invention, and the technical scope of the present invention is not limited to the specific configurations of the above embodiments. do not have.

In the above embodiment, the image obtained by photographing the surface assumed to be the exposed surface of the stone wall in the collapsed stone is used. You may detect the outline of the surface assumed to be a stone wall exposed surface.

If the chipped portion due to the collapse of the stone wall is clear, a part of the contour of the face assumed to be the exposed stone wall surface may be estimated based on the chipped portion.

As shown in FIG. 5, not only the exposed stone wall surface ES (the surface surrounded by the thick line) but also the non-exposed surface NES, which is not the exposed stone wall surface ES, may appear in the image of the collapsed stone. In this case, the contour of the exposed stone wall surface ES may be detected using the difference in brightness between the exposed stone wall surface ES and the non-exposed surface NES.

DESCRIPTION OF SYMBOLS 100... Stone restoration position specific apparatus 11... Exposed area calculation part before collapse 12... Exposed area calculation part after collapse 13... Identification part 52... Scale

Claims (3)

A stone material restoration position identifying method for identifying the restoration position of a collapsed stone material in a stone wall,
Using the image of the stone wall before it collapsed, the area of the stone wall exposed surface for each of the plurality of stone materials is calculated by image processing,
Using the image of the collapsed stone, the area of the surface assumed to be the stone wall exposed surface in the collapsed stone is calculated by image processing,
Identifying the restoration position of the collapsed stone material by comparing the area calculated using the image of the stone wall before the collapse with the area calculated using the image of the collapsed stone material;
Stone restoration location identification method. When calculating the area using the image of the collapsed stone,
Acquiring an image of the collapsed stone taken with a grid-like scale applied to the collapsed stone,
Correcting the orientation of the acquired image based on the scale,
2. The stone restoration position specifying method according to claim 1, wherein the area is calculated using the corrected image of the collapsed stone. A stone restoration position specifying device for specifying the restoration position of a collapsed stone in a stone wall,
a pre-collapse exposed area calculation unit that calculates the area of the stone wall exposed surface for each of the plurality of stones by image processing using the image of the stone wall before the collapse;
a post-collapse exposed area calculation unit that calculates, by image processing, the area of the surface assumed to be the stone wall exposed surface of the collapsed stone, using the image of the collapsed stone;
a stone restoration position, comprising: a specifying unit for specifying the restoration position of the collapsed stone by collating the area calculated by the pre-collapse exposed area calculation unit and the area calculated by the post-collapse exposed area calculation unit. Specific device.

Images