JP7843328B2 - Method for measuring the thickness of coating material - Google Patents

Description

This invention relates to a method for measuring the thickness of a covering material applied to surface areas such as walls, floors, ceilings, and rooftops of buildings.

Various functional layers are formed on building walls and other surfaces using methods such as painting, plastering, and spraying. For example, a foaming agent, added to the main raw material, is sprayed onto the wall and allowed to foam and solidify to create insulation. To ensure the insulation thickness is within a specified range, after spraying the foaming agent onto the surface and allowing it to foam and solidify, the thickness is checked. Excess material is trimmed in areas that are too thick, and additional material is added in areas that are too thin. Traditionally, at construction sites, after installation, a needle-shaped measuring gauge was inserted into various points in the foamed and solidified insulation to measure its thickness and determine if any adjustments were necessary. However, this only provided discrete measurements at the points where the gauge was inserted, making comprehensive quality control across the entire surface impossible.

To address the above problem, Patent Document 1 describes a method for measuring the thickness of a coating material applied to a target surface, in which a virtual plane is calculated based on three or more reference three-dimensional coordinates of known and identical distances from the target surface, using the three-dimensional coordinates of a reference marker placed on or near the coating material as reference three-dimensional coordinates, and the thickness of the coating material is calculated based on the three-dimensional coordinates of the surface of the coating material and the said virtual plane. Patent Document 2 describes a measuring pin for measuring the thickness of an insulating material applied to a target surface, in which a pressing portion provided on the head can be used as a reference marker located at a predetermined distance from the target surface.

Patent Document 3 describes a method for applying fire-resistant coatings, in which a target thickness object, made of the same components as the object to be coated, is placed on the surface of the object to be coated, and the fire-resistant coating is applied using this target thickness object as a guide. This method allows for application while visually confirming the target thickness, thus reducing variations in thickness. Furthermore, it describes a painting process where image information of the surface irregularities is acquired using a 3D scanner, and it is determined that a coating of the predetermined thickness has been formed when the irregularities of the target thickness object disappear.

International Publication No. WO2020/179336 Japanese Patent Publication No. 2020-143965 Japanese Patent Publication No. 2020-125620

However, the methods described in Patent Documents 1 and 2 had a problem: after measuring the thickness of the coating material and removing the pins, pinholes remained in the coating material, and using multiple pins to improve the accuracy of thickness measurement resulted in an increase in the number of holes.

Furthermore, while the method described in Patent Document 3 allows for the determination of a predetermined thickness of coating material by focusing on the unevenness of the painted surface, it was difficult to precisely measure the coating thickness across the surface. Especially in spray application methods, since a target thickness equal to the planned thickness of the coating material is used as a guideline for the coating thickness, it was difficult to apply the coating without embedding the target thickness in the coating material, making it even more difficult to precisely measure the coating thickness across the surface.

This invention has been made in consideration of the above, and aims to provide a method for precisely measuring the thickness of a coating material over a surface area without using measuring pins that are installed after the coating material has been applied, and a measuring reference body used in such a measurement method.

The measuring reference body of the present invention is a measuring reference body for measuring the thickness of a coating material applied to a target surface, having the same function as the coating material, having a base that is fixed to the target surface, and the height from the base to the top is greater than the planned thickness of the coating material. Here, the same function as the coating material possessed by the measuring reference body refers to the function intended for the application of the coating material.

The present invention provides a method for measuring the thickness of a coating material using the above-described measurement reference bodies, comprising the steps of: fixing three or more of the measurement reference bodies, each having the same height from the bottom to the top, to the target surface; obtaining the construction shape, including the three-dimensional shape of the coating material surface and the top, after the coating material has been applied to the target surface on which the measurement reference bodies are fixed; setting measurement reference points at the tops of the three or more measurement reference bodies; and calculating the thickness of the coating material based on the three-dimensional shape of the coating material surface and the three-dimensional coordinates of the measurement reference points.

According to the present invention's measurement reference body or coating thickness measurement method, after the coating material has been applied, the absolute value and distribution of the coating material's thickness can be precisely measured surfacely based on the three-dimensional shape of the coating material's surface and the three-dimensional coordinates of the measurement reference point set at the top of the measurement reference body. Furthermore, since the measurement reference body has the same function as the coating material, there is no need to remove the measurement reference body from the coating material after thickness measurement. Unlike the method using measurement pins, there is no problem of pinholes remaining in the coating material. Also, because the thickness of the measurement reference body is greater than the planned thickness of the coating material, the measurement reference body does not become embedded in the coating material, enabling accurate thickness measurement.

This is an example of the configuration of a measurement system used in a method for measuring the thickness of a coating material according to one embodiment. This is a measurement reference body according to one embodiment. This is a process flow chart of a coating material application operation, including a method for measuring the thickness of the coating material according to one embodiment. A to E: These are diagrams illustrating the steps of a method for measuring the thickness of a coating material according to one embodiment.

An embodiment of the measurement reference body and coating material thickness measurement method of the present invention will be described with reference to Figures 1 to 4.

The method for measuring the thickness of a coating material in this embodiment involves fixing a measurement reference body to the surface to be applied, and after the coating material is applied, performing three-dimensional measurements on the coating material and the measurement reference body. The thickness of the coating material is then calculated based on a measurement reference point set at the top of the measurement reference body. In the following description, we will assume a case where the wall surface of a building is the target surface and the insulation material sprayed onto it is the coating material, and the thickness of the insulation material is measured.

Referring to Figure 1, the measurement system 10 used in this embodiment comprises a three-dimensional measuring device 11, a control unit 14, and a display unit 17. The control unit 14 includes a storage unit 15 and a data processing unit 16. The storage unit 15 stores the construction shape and other data measured by the three-dimensional measuring device 11. The data processing unit 16 performs various calculations for three-dimensional measurement and for calculating the thickness of the insulation material, and creates an image to be displayed on the display unit 17. The display unit 17 is, for example, a liquid crystal monitor that displays the image created by the data processing unit 16.

The 3D measuring device 11 measures the construction shape. The construction shape includes the 3D shape of the surface of the insulation material (covering material) 21 installed on the wall surface (target surface) 20, and the 3D shape of the top portion of the measurement reference body 30, fixed to the wall surface, that protrudes from the insulation material.

The type of 3D measuring device 11 is not particularly limited. Devices such as a LiDAR system, which irradiates the surface to be measured with laser light and calculates the 3D shape of the surface using the reflected light; a Time-of-Flight (TOF) system, which measures distance based on the time it takes for the irradiated light to reflect and return; a stereo system, which calculates the 3D shape using the principle of triangulation from images captured by two cameras; and an active stereo system, in which one of the two cameras in a stereo system is replaced with a projector that projects linear or other patterned light, can be used.

The 3D measurement device 11 preferably uses an active stereo system. This is because the stereo system offers high measurement accuracy when the distance to the measurement target is short, such as during indoor measurements. Furthermore, by projecting a pattern, stereo corresponding points can be easily searched within the pattern even in locations with few distinctive features such as walls, floors, and roofs. Figure 1 shows an active stereo 3D measurement device 11 that projects a pattern, such as infrared light, from a projection unit 13 and captures it using an imaging unit 12.

Preferably, the 3D measuring device 11 is a handheld type that can perform 3D measurements while shifting the measurement area and sequentially synthesize the measurement results to obtain the 3D shape of the entire target surface. In narrow, obstacle-filled indoor construction sites, a handheld type is preferable to a stationary type due to its superior operability.

Furthermore, it is preferable that the construction shape includes color information. For example, if a 3D measurement device capable of acquiring color images simultaneously with 3D coordinates is used, point cloud data with added color information can be generated. This allows for the identification of the measurement reference body 30 in the image based on the color information.

Figure 2 shows an example of a measurement reference body. The measurement reference body 30 comprises a base 31 and a top 32. The base 31 is fixed to the target surface 20 prior to the application of the covering material 21. The base is preferably a flat surface. The measurement reference body 30 is used with a height H greater than the planned thickness of the covering material after application. This ensures that the top 32 protrudes from the insulation material even after its application. The top 32 is preferably a flat surface parallel to the target surface when the measurement reference body is fixed to the target surface. A measurement reference point, which serves as the basis for measurement during three-dimensional measurement of the construction shape, is set on the top. By making the top a flat surface parallel to the target surface, the position of the measurement reference point can be calculated with high accuracy. Preferably, the top has a different color from the covering material and other parts of the measurement reference body. This is to facilitate identification by image. For example, the surface of the top can be colored.

The overall shape of the measurement reference body 30 can be determined considering ease of manufacturing, ease of application of the covering material 21 while fixed to the target surface 20, and resistance to detachment after application. From the viewpoint of ease of manufacturing, it is preferable for the measurement reference body to have various columnar shapes such as prisms and cylinders, and more preferable for it to have a rectangular parallelepiped shape including a cube. If the shape of the measurement reference body is a rectangular parallelepiped, it can be manufactured by cutting only without machining, and there is no waste of material during manufacturing, and the filling efficiency during packaging and transportation is good. On the other hand, if the importance is not to interfere with the application work, it is preferable for the measurement reference body to have a columnar shape such as a cylinder with no corners on the sides, or various frustum shapes such as a frustum of a pyramid and a frustum of a cone, more preferable for it to have a frustum shape, and particularly preferable for it to have a frustum shape with no corners on the sides such as a frustum of a cone. If the shape of the measurement reference body is a frustum of a cone, even when using a site-foamed spray polyurethane insulation material, which is relatively difficult to apply, it is easy to apply without leaving voids around the measurement reference body. Furthermore, if the measurement reference body has a frustum shape, fixing it to the target surface using the larger of the two parallel planes of the frustum as the base will prevent the measurement reference body from falling out of the covering material even if its attachment to the target surface becomes loose or detached due to changes over time after installation.

The measurement reference body 30 has the same function as the covering material. Here, "same function" refers to the function intended for the application of the covering material. For example, if the covering material is an insulating material, it has an insulating function; if it is a fire-resistant covering, it has a fire-resistant function; and if it is a waterproof covering, it has a waterproof function. This allows the measurement reference body to remain in the covering material without being removed after application.

The material of the measurement reference body 30 is preferably substantially the same as that of the covering material 21. "Substantially the same material" means that the components and structure of the measurement reference body are similar to those of the covering material, and even if there are differences in components or structure, the differences are within a range that does not impair the function intended for the above-mentioned construction. This ensures that the measurement reference body has the same function as the covering material, and also provides good adhesion between the measurement reference body and the covering material. For example, if the covering material is a field-foamed spray polyurethane insulation material, it is preferable that the measurement reference body be made of foamed polyurethane material. However, even in this case, it is not necessary to cut and manufacture the measurement reference body from the insulation material foamed by the spraying process; for example, the hardness of the measurement reference body and the covering material may differ due to differences in foaming ratios.

The measurement reference body 30 preferably has a protective film 33 on its top 32. Since the height of the measurement reference body is greater than the thickness of the covering material, the top will not be buried by the covering material after application. However, when the covering material is sprayed on, splashes may adhere to the top, causing errors in three-dimensional measurement. By providing a protective film on the top of the measurement reference body, a flat and clean top surface, free from splashes and other unwanted contaminants, is revealed when the protective film is removed after the covering material has been applied. Furthermore, using a colored protective film makes it easier to detect if the protective film has been forgotten to be removed.

Next, the method of this embodiment will be explained following the flowchart in Figure 3, with reference to Figure 4. In the following, the direction in which the target surface extends will be referred to as the "surface direction," and the direction perpendicular to it will be referred to as the "thickness direction." Furthermore, objects located in front of the target surface when viewed from the thickness direction will simply be said to be "within the plane" of the target surface. The same applies to the coating material.

The coating thickness measurement method of this embodiment involves (S1) fixing a measurement reference body to the target surface 20, (S2) applying the coating material, (S3) acquiring the application shape, (S4) setting a measurement reference point at the top of the measurement reference body to calculate a virtual plane, and (S5) calculating the coating material thickness. The application work continues, after which (S6) an image of the coating material is displayed, and (S7) it is determined whether correction processing is necessary. If correction processing is deemed necessary, (S8) the correction processing is performed, and then steps S3 onwards are repeated. If correction processing is deemed unnecessary, (S9) finishing processing is performed, and (S10) the required data is saved to complete the work.

(S1) The bottom surface 31 of the measurement reference body 30 is fixed to the wall surface 20, which is the target surface (Figure 4A). The measurement reference body in Figure 4A has a protective film 33 on its top 32. The method of fixing the bottom surface 31 to the wall surface is not particularly limited, and various known adhesives and sealants such as acrylic, urethane, and silicone, or double-sided tape with adhesive layers on both sides can be used. If the covering material is a field-foamed spray urethane insulation material, it is preferable to use an acrylic adhesive or sealant that has heat resistance to the heat generated during construction.

The measurement reference body 30 is fixed at three or more locations within the target surface that are not on a straight line. This allows a virtual plane parallel to the target surface, passing through the measurement reference point, to be defined later when a measurement reference point is set at the top 32. Preferably, the measurement reference body is fixed at four or more locations. As will be described later, the more measurement reference bodies there are, i.e., the more measurement reference points there are, the more accurate the measurement of the coating thickness can be improved. Furthermore, it is preferable to distribute the measurement reference body across the entire surface of the target surface. As will be described later, this improves the accuracy of the measurement of the coating thickness.

(S2) The insulation material 21, which is the covering material, is applied to the wall surface 20, which is the target surface (Figure 4B). The method of application is not particularly limited. For example, rigid polyurethane foam for building insulation specified in JIS A9526 can be applied by spraying. When applying the covering material by spraying, splashes 22 of the raw material may adhere to the top 32 of the measurement reference body 30. To address this problem, a protective film 33 can be attached to the top of the measurement reference body and removed before obtaining the application shape in the next step S3. The type of covering material is not particularly limited and may form various layers such as an insulation layer, fireproof covering layer, fire-resistant covering layer, waterproof covering layer, moisture-proof covering layer, and corrosion-resistant covering layer. The covering material can also be applied by various methods such as spraying, coating, etc.

(S3) The construction shape C is acquired using the 3D measuring device 11 (Figure 4C). The construction shape includes the 3D shape of the surface of the covering material 21 and the 3D shape of the top 32 of the measurement reference body 30 protruding from the covering material. If the measurement reference body has a protective film 33 on its top, the protective film is removed before acquiring the construction shape. The method of representing the 3D shape is not particularly limited as long as it can be processed on a computer. For example, it may be represented as point cloud data, which is a set of 3D coordinates of the surface, or as a polygon mesh, mathematical formulas or parameter representations of planes/curved surfaces, or as volume data representations of the target area (voxels, etc.), or a combination thereof.

(S4) A measurement reference point R is set on the top 32 of the measurement reference body 30, and the virtual plane V is calculated (Figure 4D). If the top 32 is a plane, setting the measurement reference point R at its centroid allows for easy and accurate calculation of the measurement reference point's position using image processing. However, if splashes of coating material or other debris are attached to the top 32, this can cause errors in the calculation of the measurement reference point R's position. To address this problem, as mentioned above, a measurement reference body equipped with a protective film 33 on its top can be used.

If multiple measurement reference points have the same height H, then the distance from the target plane 20 to the measurement reference point R set at the top of each measurement reference point will be equal. Therefore, by connecting multiple measurement reference points, a virtual plane V parallel to the target plane can be determined. A virtual plane V can be calculated with three measurement reference points. If there are four or more measurement reference points, the virtual plane V can be determined with higher accuracy by fitting using methods such as the least squares method.

(S5) The thickness of the insulating material 21 is calculated based on the three-dimensional shape of its surface and the three-dimensional coordinates of three or more measurement reference points R (Figure 4E). The distance between the virtual plane V and the target surface 20 is known and equal to the height H of the measurement reference body 30. Therefore, by calculating the distance t1 between the virtual plane V and the surface of the insulating material 21 and subtracting it from H, the distance from the target surface 20 to the surface of the insulating material, i.e., the thickness t2 of the insulating material, can be obtained as t2 = H - t1.

Based on the above, the absolute value and distribution of the coating material thickness can be determined across the entire surface. Details of the method for calculating the coating material thickness are disclosed in Patent Document 1.

(S6) A covering material image is created and displayed on the display unit 17. Here, the covering material image refers to an image in which the thickness t2 of the insulating material 21, which is the covering material, can be recognized. The covering material image can, for example, be a contour map showing the insulating material in multiple regions color-coded or with varying shades of gray according to its thickness. This makes it easy to identify parts of the covering material whose thickness falls outside the predetermined range based on the required specifications.

(S7) Based on the image of the covering material, if there are areas where the thickness of the covering material does not meet the required specifications, it is determined that correction processing is necessary; otherwise, it is determined that correction processing is unnecessary.

(S8) If it is determined in step S7 that correction processing is necessary, the coating material is modified. Specifically, areas where the coating material is too thick are trimmed, and areas where it is too thin are coated with additional coating material. After the correction processing, the construction shape is acquired again (S3), measurement reference points are set (S4), the thickness of the coating material after the correction processing is calculated (S5), the image of the coating material is displayed (S6), and it is determined whether further correction processing is necessary (S7).

(S9) If it is determined that no correction is necessary in step S7, the process proceeds to the finishing stage. In the finishing stage, any portion of the measurement reference body 30 protruding from the coating material is cut off. Additionally, if necessary, a topcoat is applied to protect the entire surface of the coating material.

(S10) Various data such as the thickness of the covering material, images of the covering material, and construction shape are saved. Specifically, the data stored in the storage unit 15 is copied to a storage medium or to a server in another location via the network. By saving data such as the thickness of the covering material, it can be used later for quality assurance to the client.

Furthermore, among the above steps, the application of the coating layer (S2), the correction treatment (S8), and the finishing treatment (S9) may be carried out by a different business operator than the other steps constituting the coating layer thickness measurement method of this embodiment.

The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the technical idea of the invention.

For example, the target surface is not limited to the walls of a building; it may also be a surface area such as a floor, roof, ceiling, or rooftop. Furthermore, the covering material is not limited to spray-applied insulation; it may be a material other than insulation that possesses waterproofing, fire resistance, fireproofing, non-combustible, flame-retardant, or a combination of these functions.

10 Measurement system 11 Three-dimensional measuring device 12 Imaging unit 13 Projection unit 14 Control unit 15 Storage unit 16 Data processing unit 17 Display unit 20 Wall surface (target surface)
21. Insulation material (covering material)
22 Splashes of insulation material raw material 30 Measurement reference body 31 Bottom surface 32 Top surface 33 Protective film C Construction shape H Height of measurement reference body R Measurement reference point t1 Distance between the surface of the covering material and the virtual plane t2 Thickness of the covering material V Virtual plane

Claims (6)

A method for measuring the thickness of a coating material applied to a target surface ,
A step of preparing a measuring reference body having the same function as the intended function of the application of the aforementioned covering material, having a bottom surface fixed to the target surface and a top portion equipped with a curing film, and having a height from the bottom surface to the top portion greater than the planned thickness of the covering material to be applied,
A step of fixing the bottom surfaces of three or more of the measurement reference bodies, each having the same height from the bottom surface to the top surface, to the target surface,
After the covering material is applied to the target surface on which the measurement reference body is fixed, a step is taken to obtain the construction shape including the three-dimensional shape of the surface and top of the covering material,
A step of setting measurement reference points on the tops of three or more of the aforementioned measurement reference bodies,
A step of calculating the thickness of the coating material based on the three-dimensional shape of the surface of the coating material and the three-dimensional coordinates of the measurement reference point,
A method for measuring the thickness of a covering material. The measurement reference body is made of substantially the same material as the covering material.
The method for measuring the thickness of a coating material according to claim 1. The aforementioned covering material is an insulating material.
The method for measuring the thickness of a coating material according to claim 1 or 2. The aforementioned insulation material is a spray-on foamed polyurethane.
The method for measuring the thickness of a coating material according to claim 3. The top of the measurement reference body is a plane parallel to the bottom surface.
A method for measuring the thickness of a covering material according to any one of claims 1 to 4. The measurement reference body has a columnar or frustum shape,
A method for measuring the thickness of a covering material according to any one of claims 1 to 5.