How to measure buildings

Abstract

To provide a method for surveying a building, capable of efficiently surveying spaces such as an attic, under a floor, and above a ceiling in traditional architecture such as a temple or shrine architecture. [Solution] A surveying method for second spaces 24, 26, 28 which are partitioned off as separate spaces from first spaces 16, 18, 20, 22 which are open spaces in traditional architecture 2 and are out of sight, the method includes the steps of checking the condition of the introduction path of a 3D scanner into the second space, introducing the 3D scanner into the second space if the introduction path does not hinder the introduction of the 3D scanner, and acquiring three-dimensional surveying data of the second space using the 3D scanner.

Description

[Technical field]

[0001] The present invention relates to a method for surveying buildings, targeting traditional architecture such as shrines and temples, a method for generating composite point cloud data from point cloud data obtained by surveying traditional architecture such as shrines and temples using a 3D scanner, a program, and a computer-readable recording medium. [Background technology]

[0002] Surveying using a 3D scanner is being considered in places where it is time-consuming or difficult to measure with a convex (tape measure) etc. For example, surveying using a 3D scanner is being carried out to create a layout plan when adding arch trusses to large-space architectural structures such as dome-shaped stadiums (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-117041 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, the building area is 50,000 m 2 The study was aimed at large-space architectural structures exceeding 100m2, but did not take into account traditional buildings such as temples and shrines and old houses. 2 From about several hundred meters 2 At most, it is about 1000m 2 Furthermore, the target building in Patent Document 1 was constructed recently, blueprints exist, and the survey using the 3D scanner was conducted in an open space visible to users.

[0005] On the other hand, many traditional architecture such as temples and shrines and old houses have high cultural value, and drawings are required for restoration, but there are cases where drawings from the time of construction do not exist, and even if there are drawings, they do not match the current state due to expansion or renovation. In addition, when creating drawings, it is necessary to survey spaces that are not visible to users, such as attics, underfloor spaces, and ceilings, which are formed as separate spaces from the open spaces used by users (priests, temple priests, worshippers, residents, etc.). However, since attics, underfloor spaces, and ceilings in traditional architecture are not assumed to be used by users, they are often narrow spaces and tend to be difficult to survey. Even if it was possible to survey them, it was difficult to generate accurate drawings from the obtained data when using existing algorithms. [Means for solving the problem]

[0006] The object of the present invention is to provide a method for surveying buildings that can efficiently survey spaces such as attics, under floors, and above the ceiling in traditional architecture such as shrine and temple buildings, and to provide a method, program, and computer-readable recording medium for generating synthetic point cloud data that can generate highly accurate synthetic point cloud data based on point cloud data obtained by surveying traditional architecture such as shrine and temple buildings using a 3D scanner.

[0007] As a result of extensive research, the inventors discovered that the above problems could be solved by a specific method for loading a 3D scanner and a specific processing of point cloud data, and thus completed the present invention.

[0008] That is, according to the present invention, (1) A method for surveying a second space that is partitioned as a separate space from a first space, which is an open space in a traditional building, and is not visible to the public, comprising the steps of: confirming the status of an introduction path of a 3D scanner into the second space; introducing the 3D scanner into the second space when the introduction path does not impede the introduction of the 3D scanner; and acquiring three-dimensional survey data of the second space by the 3D scanner; (2) The method for surveying a building according to (1), wherein the second space is at least one of an attic, a space under a floor, or a space above a ceiling. (3) The method for surveying a building according to (1) or (2), wherein the condition of the introduction path is at least one of an entrance for introducing the 3D scanner into the second space, a width of the introduction path, and a load capacity of the introduction path; (4) A method for generating composite point cloud data, comprising the steps of: acquiring first point cloud data obtained by surveying a first space, which is an open space in a traditional building, with a 3D scanner; and acquiring second point cloud data obtained by surveying a second space, which is partitioned as a space separate from the first space in the traditional building and is not visible to humans, with a 3D scanner; creating joint groups by associating small groups obtained by dividing a large space set for each acquisition unit when acquiring the first point cloud data with the second point cloud data at positions corresponding to the small groups; determining a position of the joint group in the large space; and generating composite point cloud data by synthesizing the first point cloud data and the second point cloud data based on the determined position; (5) A method for generating a point cloud current state preserved drawing, comprising the step of extracting a line drawing based on the composite point cloud data according to (4); (6) A program for causing a computer to function as a means for acquiring first point cloud data obtained by surveying a first space, which is an open space in a traditional architecture, with a 3D scanner, and second point cloud data obtained by surveying a second space, which is partitioned as a space separate from the first space in the traditional architecture and is not visible to humans, with a 3D scanner; a means for creating a joint group by combining small groups obtained by dividing a large space into a predetermined number of units set for each acquisition unit when acquiring the first point cloud data, and the second point cloud data at positions corresponding to the small groups; a means for determining a position of the joint group in the large space; and a means for generating composite point cloud data by combining the first point cloud data and the second point cloud data based on the determined position; (7) A computer-readable recording medium in which the program according to (6) is recorded. is provided. Effect of the Invention

[0009] According to the present invention, it is possible to efficiently survey spaces such as attics, under floors, and ceilings in traditional architecture such as shrines and temples. It is also possible to provide a synthetic point cloud data generation method capable of generating highly accurate synthetic point cloud data based on point cloud data obtained by surveying traditional architecture such as shrines and temples with a 3D scanner, a point cloud current status preservation drawing generation method, a program, and a computer-readable recording medium. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an outline of an example of traditional architecture such as a temple or shrine building. [Diagram 2] This is a flowchart showing the procedure for using a 3D scanner to survey hidden spaces such as temples and shrines. [Diagram 3] FIG. 2 is a block diagram showing a system configuration of a computer for generating composite point cloud data. [Figure 4] 13 is a flowchart showing a process of generating composite point cloud data. [Diagram 5] FIG. 13 is a diagram showing an example of a point cloud current status storage drawing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, a method for surveying a building and a method for generating composite point cloud data according to an embodiment of the present invention will be described with reference to the drawings. The method for surveying a building of the present invention is a method for surveying a second space that is partitioned as a separate space from a first space, which is an open space in traditional architecture, and is not visible to the public, and includes the steps of checking the status of an introduction path of a 3D scanner into the second space, introducing the 3D scanner into the second space when the introduction path does not impede the introduction of the 3D scanner, and acquiring three-dimensional survey data of the second space by the 3D scanner.

[0012] In addition, the method for generating composite point cloud data of the present invention includes the steps of acquiring first point cloud data obtained by surveying a first space, which is an open space in traditional architecture, with a 3D scanner, and second point cloud data obtained by surveying a second space, which is partitioned as a separate space from the first space in the traditional architecture and is not visible to the public, with a 3D scanner; creating joint groups by matching small groups obtained by dividing a large space set for each acquisition unit when acquiring the first point cloud data into a predetermined number of units with the second point cloud data at positions corresponding to the small groups; determining a position of the joint group in the large space; and generating composite point cloud data by synthesizing the first point cloud data and the second point cloud data based on the determined position.

[0013] Fig. 1 is a schematic diagram of an example of traditional architecture such as a temple or shrine. As shown in Fig. 1, in a traditional wooden building 2, a foundation stone 6 is placed on a foundation 4, and a pillar 8 is provided on the foundation stone 6. Furthermore, at the top of the pillar 8, a girders 10 is provided as a horizontal structural member and joined to the pillar 8. A roof 11 is provided above the girders 10.

[0014] Additionally, a ceiling material 12 is provided above the pillars 8 and below the girder 10 so as to be joined to the pillars 8, and a floor material 14 is joined to the lower part of the pillars 8. Additionally, a crossbeam 16 is joined to the pillars 8.

[0015] Each part is joined based on traditional construction methods such as tenons and joists, but metal fittings such as anchor bolts may also be used in the attachment parts. The roofing material for the roof 11 is not particularly limited, but tiles, copper plates, thatch, etc. may be used. The traditional architecture 2 has been described as being configured with pillars 8 attached to cornerstones 6, but it may also be configured with foundations or the like.

[0016] Here, the open space formed between the floor material 14 and the ceiling material 12 is a space that can be used by users (for example, a Shinto priest, a head priest, or worshippers) as a porch 17, a veranda 18, an outer sanctuary 20, and an inner sanctuary 22.

[0017] On the other hand, the underfloor space 24 formed between the floor material 14 and the ground 4, the attic space 26 formed between the ceiling material 12 and the girders 10, and the attic space 28 formed between the girders 10 and the roof 11 are spaces that cannot be seen by users, that is, spaces that are not visible to the public. Also, the underfloor space 24, the attic space 26, and the attic space 28 are spaces that are not envisaged as spaces that can be used by users.

[0018] Next, a procedure for measuring a traditional building 2 such as a temple or shrine building using a 3D scanner will be described with reference to the flowchart shown in Fig. 2. First, the exterior is measured using a 3D scanner (step S1), and then, regarding the interior of the traditional building 2, the open spaces visible to users (such as the porch 17, veranda 18, outer sanctuary 20, and inner sanctuary 22) are measured using a 3D scanner (step S2).

[0019] Next, the hidden spaces (underfloor space 24, attic space 26, and attic space 28) are surveyed using a 3D scanner. Here, the hidden spaces (underfloor space 24, attic space 26, and attic space 28) have narrow entrances to enter these spaces (i.e., access points for bringing in and taking out the 3D scanner), and the interiors are narrow because they are not designed as spaces for users, and furthermore, they are not designed to let in light, so they tend to be dark.

[0020] First, it is confirmed whether or not a 3D scanner can be brought in from an entrance of a space that is not visible to the public (underfloor space 24, attic space 26, or attic space 28) (step S3). In other words, it is confirmed whether or not the opening is large enough to bring in the 3D scanner.

[0021] The 3D scanner may be of the contact type or non-contact type, but it is preferable to use a non-contact type, i.e., a 3D laser scanner. The scanning method of the 3D laser scanner may be a pulse type or a phase difference type.

[0022] In addition, the 3D scanner may be a handheld type or a stationary type, but from the viewpoint of measurement accuracy, a stationary type is preferable. In the present invention, for example, a Trimble X7 (external dimensions: width 178 mm × height 353 mm, depth 170 mm) can be used. Note that the Trimble X7 can perform surveying if the distance to the measurement object is at least 60 cm.

[0023] If the 3D scanner can be brought in from an entrance to a space that is not visible to the public (underfloor space 24, attic space 26, or attic space 28), the introduction route of the 3D scanner is confirmed (step S4). For example, confirmation is made as to whether the gap between pillars is large enough to allow the 3D scanner to pass through, whether the strength of the surface functioning as the floor can withstand the introduction of the 3D scanner, etc. If it is confirmed that there are no obstacles to the introduction of the 3D scanner, an introduction route that does not impede the introduction of the 3D scanner is determined.

[0024] For example, in the attic space 28, there may be many pillars for constructing the roof design, and the spacing between structures such as pillars may be narrow in the underfloor space 24. Therefore, there are some places between structures where the 3D scanner cannot pass through. Furthermore, there are some places in the underfloor space 24 where a person needs to crawl when entering.

[0025] In addition, the surfaces that function as floors in the attic space 28 and the ceiling space 26 are not expected to be used by users, so some parts are not strong enough. Also, in the case of traditional architecture with high cultural value, it is necessary to avoid damaging the building, especially when introducing a 3D scanner. Therefore, when introducing a 3D scanner, it is necessary to check whether there are any obstacles to its introduction.

[0026] The spacing that the 3D scanner can pass through and the strength of the surface that functions as the floor may be measured using a known measuring device, or may be investigated in advance by a carpenter or other person familiar with the structure of traditional architecture such as shrine and temple architecture.

[0027] If it is determined that there is no problem with introducing the 3D scanner, the 3D scanner is introduced into an out-of-sight space (underfloor space 24, attic space 26 or attic space 28) based on the determined introduction route, and a survey of the out-of-sight space (underfloor space 24, attic space 26 or attic space 28) is performed using the 3D scanner (step S5).

[0028] The 3D scanner may be self-propelled, with a pre-programmed introduction path, and may be introduced along the programmed introduction path, or may be remotely controlled. At the survey point, it is desirable to survey as many directions as possible, and for example, it is preferable to perform a 360° survey in multiple sessions. For example, remote control may be used for the survey. By following the above procedure, surveying of traditional architecture2 such as temples and shrines can be performed using a 3D scanner, and point cloud data can be obtained as 3D measurement data.

[0029] Next, synthesis of point cloud data as three-dimensional measurement data obtained by surveying with a 3D scanner will be described. FIG. 3 is a block diagram showing the system configuration of a computer used for synthesizing point cloud data. As shown in FIG. 3, the computer 30 includes a CPU 32, to which a memory 34, a communication unit 36 ​​for receiving point cloud data from the 3D scanner, a storage unit 38 for storing point cloud data obtained by the 3D scanner, etc., a synthetic point cloud data generating unit 40 for synthesizing point cloud data by a program for generating synthetic point cloud data and generating synthetic point cloud data, a drawing output unit 42 for outputting various drawings based on the synthetic point cloud data, a display unit 44 consisting of a liquid crystal display or the like for displaying the drawings output by the drawing output unit 42, and an input unit 46 for inputting various operation instructions to the CPU 32 are connected.

[0030] 4 is a flowchart showing the point cloud data synthesis process. When a point cloud data synthesis command is input by the input unit 46, the CPU 32 reads out the point cloud data from the storage unit 38 to the memory 34 (step S11). Here, the point cloud data stored in the storage unit 38 is data obtained by surveying the traditional architecture 2 such as the above-mentioned shrine or temple architecture using a 3D scanner. The point cloud data is obtained from the 3D scanner via the communication unit 36, for example, and stored in the storage unit 38.

[0031] Next, the CPU 32 performs a synthesis process of the point cloud data. Generally, when surveying the same space in multiple directions or from multiple locations using a 3D scanner, a reference point for alignment can be set to obtain synthesized point cloud data with less error. For example, when synthesizing point cloud data obtained in the same space, the survey direction of the 3D scanner is moved six times at intervals of about 60° from the approximate center of the space during surveying, and point cloud data for a total of 360° is obtained. At this time, a reference point can be set for each survey direction. Then, the point cloud data obtained in one survey (for example, data of about 60°) is defined as, for example, one large space, and the point cloud data obtained in the above six surveys, that is, the point cloud data for six large spaces, can be synthesized based on the reference point to obtain synthesized point cloud data.

[0032] In the present invention, as described above, it is necessary to synthesize point cloud data obtained by surveying the exterior, open spaces, and secluded spaces of traditional architecture 2 such as shrines and temples.

[0033] In traditional architecture 2 such as temples and shrines, the parts where the exterior and open spaces connect are visible, making it easy to set reference points for alignment. Therefore, when combining point cloud data obtained by surveying the exterior with point cloud data obtained by surveying the open spaces (porch 17, veranda 18, outer sanctuary 20, inner sanctuary 22, etc.), it is possible to obtain combined point cloud data with fewer errors based on the reference points.

[0034] On the other hand, when combining point cloud data obtained by surveying open spaces (such as the porch 17, veranda 18, outer sanctuary 20, and inner sanctuary 22) with point cloud data obtained by surveying hidden spaces (such as the underfloor space 24, attic space 26, and attic space 28), it is difficult to set a reference point for alignment, and even if it is possible to do so, the point cloud data tends to be combined with errors if they are combined as is. In other words, as in the algorithm for combining point cloud data of large spaces as described above, the errors will be large when attempting to combine point cloud data using a reference point. Therefore, in the present invention, a small group smaller than the large space is created, and a joint group is created based on the small group (step S12).

[0035] For example, when point cloud data obtained by one survey using a 3D scanner in an open space is defined as one large space, multiple small groups smaller than the large space are created. That is, multiple small groups are created by dividing one large space into multiple parts. Then, for each position of the small groups, a corresponding position of an out-of-sight space (an out-of-sight space located behind the open space) is combined to create a joint group. That is, the joint group includes point cloud data of the open space included in the small group and point cloud data of the out-of-sight space at a position corresponding to the small group. Here, there is no particular limit to the number of small groups created in the large space, but it is possible to create several to several hundred small groups.

[0036] Regarding a joint group, for example, a combination of point cloud data of a specified position on the ceiling obtained by surveying an open space and point cloud data of a corresponding position (behind the specified position on the ceiling) obtained by surveying the attic space 26 becomes a joint group.

[0037] In addition, a joint group is formed by combining point cloud data of a specified position on the floor obtained by surveying the open space and point cloud data of a corresponding position (the back side of the specified position on the floor) obtained by surveying the underfloor space 24.

[0038] In addition, when an open space and an attic space 28 are adjacent, a joint group is formed by combining point cloud data of a specified position related to the main girder 10 obtained by surveying the open space and point cloud data of a corresponding position (the back side of the specified position related to the main girder 10) obtained by surveying the attic space 28.

[0039] In addition, if there is an attic space 26 between the open space and the attic space 28, a joint group may be created by combining point cloud data of a specified position on the ceiling obtained by surveying the open space with point cloud data of a corresponding position (behind the specified position on the ceiling) obtained by surveying the attic space 26 and the attic space 28, or a process of creating a joint group twice may be performed.

[0040] When creating a joint group twice, a first joint group is created by combining point cloud data of a predetermined position related to attic space 28 obtained by surveying attic space 26 with point cloud data of a corresponding position (behind the predetermined position related to attic space 26) obtained by surveying attic space 28, and then a second joint group is created by combining point cloud data of a predetermined position corresponding to the first joint group obtained by surveying the open space with point cloud data included in the first joint group. In this case, the second joint group is used as the joint group in the subsequent processes.

[0041] Next, the CPU 32 performs a process of making the joint group follow the large space (step S13). That is, the CPU 32 performs a process of determining the position of the joint group in the large space. Then, the CPU 32 causes the composite point cloud data generating unit 40 to generate composite point cloud data based on the joint group (step S14).

[0042] This allows for the synthesis of point cloud data with fewer errors. In addition, the accuracy of the point cloud current status saved drawing (described later) is improved, allowing for the output of a drawing that is closer to the current status. Based on the obtained composite point cloud data, the CPU 32 causes the drawing output unit 42 to output a drawing in a predetermined format, and causes the display unit 44 to display the drawing.

[0043] For example, a line drawing extracted from point cloud data can be generated as a point cloud current status preservation drawing. An example of a point cloud current status preservation drawing is shown in Figure 5. A point cloud current status preservation drawing can be positioned as a faithful preservation drawing that preserves the current state. In addition, a point cloud current status preservation drawing can be used to archive traditional architecture with high cultural value, such as historical buildings, or as a digital twin. In addition, after synthesizing the point cloud data, it can be converted into two dimensions, dimensions can be added, and construction drawings and marking out drawings can be generated. In addition, the point cloud current status preservation drawings, construction drawings, marking out drawings, etc. can be printed out on paper for use as well as displayed on the display unit 44.

[0044] In addition, computer 2 may be a tablet terminal, and if the operator determines that the drawing displayed on display unit 44 based on the surveying results does not fully display the current situation, the process of generating the composite point cloud data may be re-executed, and since the accuracy of the point cloud data obtained may be affected by the measurement angle, installation position, etc. of the 3D scanner, the survey may be performed again using the 3D scanner.

[0045] In addition to the above-mentioned processes, if necessary, during or after the synthesis, it is possible to perform processes such as trimming unnecessary parts, and after synthesizing the point cloud data, it is possible to perform processes such as filling in data or smoothing processes for parts where no point cloud data exists (i.e. parts where survey data could not be obtained by the 3D scanner).

[0046] In the above-mentioned embodiment, a first point cloud data obtained by surveying a first space, which is an open space in a traditional building, with a 3D scanner, and a second point cloud data obtained by surveying a second space, which is partitioned as a space separate from the first space in the traditional building and is not visible to the public, with a 3D scanner are obtained, and a joint group is created by combining a small group obtained by dividing a large space into a predetermined number of units set for each acquisition unit when acquiring the first point cloud data with the second point cloud data at a position corresponding to the small group, and a position of the joint group in the large space is determined. A program for generating composite point cloud data by combining the first point cloud data and the second point cloud data based on the determined position may be downloaded via a network such as the Internet and incorporated into a computer, thereby causing the computer to function so as to perform the above-mentioned composite point cloud data generation process.

[0047] The program may be recorded on a computer-readable recording medium such as a flexible disk, a CD-ROM, a DVD, a Blu-Ray, etc. In other words, the program may be read from the computer-readable recording medium and installed in a computer to cause the computer to function so as to perform the above-mentioned process of generating the composite point cloud data. [Explanation of symbols]

[0048] 2...Traditional architecture such as temples and shrines, 6...Foundation stone, 10...Beam, 11...Roof, 12...Ceiling material, 14...Floor material, 17...Veranda, 18...Wide veranda, 20...Outer sanctuary, 22...Inner sanctuary, 24...Underfloor space, 26...Attic space, 28...Attic space

Claims

1. A survey method for a second space that is partitioned as a separate space from a first space, which is an open space in traditional architecture, and is not visible to the public, A step of checking the status of an introduction path of the 3D scanner into the second space; When the introduction path does not impede the introduction of the 3D scanner, introducing the 3D scanner into the second space; acquiring three-dimensional survey data of the second space by the 3D scanner; A method for surveying a building, comprising: A method for surveying a building, wherein the condition of the introduction route is the load-bearing capacity of the introduction route.

2. The method for surveying a building according to claim 1 , wherein the second space is at least one of an attic, a space under a floor, and a space above a ceiling.

3. The method for surveying a building according to claim 1 or 2, wherein the condition of the introduction path further includes at least one of the width of an entrance for introducing the 3D scanner into the second space and the width of the introduction path.

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