Three-dimensional surface roughness evaluation method

Abstract

A three-dimensional surface roughness evaluation device and a three-dimensional surface roughness evaluation method are provided that can quickly obtain surface roughness parameters relating to the three-dimensional surface roughness of an untransportable object, structure, or the like. [Solution] A three-dimensional surface roughness evaluation device comprising a two-dimensional laser displacement meter, a movement mechanism that moves the two-dimensional laser displacement meter in the X-axis direction, a movement distance reading device that reads the movement distance of the two-dimensional laser displacement meter in the X-axis direction, and a calculation device that generates three-dimensional surface roughness data of the object to be measured based on the displacement data acquired by the two-dimensional laser displacement meter and the movement distance data acquired by the movement distance reading device. The two-dimensional laser displacement meter is positioned so that its width direction coincides with the Y-axis direction, and the calculation device is configured to average the displacement data acquired by the two-dimensional laser displacement meter at regular intervals in the X-axis direction in the Y-axis direction to generate reference surface data for each coordinate, and to generate three-dimensional surface roughness data for the object to be measured.

Description

[Technical Field]

[0001] The present invention provides a method for obtaining surface roughness parameters relating to the three-dimensional surface roughness of non-portable objects, structures, etc. Ru3 Specifically, the present invention relates to a method for evaluating two-dimensional surface roughness, which can rapidly, continuously, and directly obtain surface roughness parameters in large quantities. Ru3 This relates to a two-dimensional surface roughness evaluation method. [Background technology]

[0002] The surface roughness profile of an object is important for understanding the friction characteristics of that surface. In recent years, as shown in Non-Patent Document 1, the importance of measuring not only roughness height but also shape parameters including wavelength has been shown to be important for understanding the water flow friction characteristics of an object surface.

[0003] Non-patent document 1 describes the evaluation of the surface roughness of a ship's hull (paint surface roughness), and indicates that in order to evaluate the surface roughness of an object or structure that cannot be transported, such as a ship's hull, it is necessary to measure a sufficient number of shape parameters over an extremely wide range.

[0004] Furthermore, it has been pointed out that when using a conventional roughness measuring device, the BSRA Hull Roughness Analyzer, it is not possible to perform precise measurement of hull surface roughness or parameter analysis. To solve this problem, Non-Patent Document 1 creates a roughness replica of the hull surface using thermoplastic resin, and measures the hull surface roughness by performing surface analysis of the roughness replica in a laboratory using a point laser displacement meter mounted on an XY stage.

[0005] Patent Document 1 proposes a non-contact roughness measuring device for measuring the roughness of untransportable objects and structures, which uses a shadow image recording device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 61-292509 [Non-patent literature]

[0007] [Non-Patent Document 1] Hiroo Mieno, Hiroshi Masuda, "Increase in Resistance Due to Surface Roughness of Ship Bottom Paint - Reduction of Ship Hull Resistance by Bottom Hull Paint", Journal of the Japan Society of Marine Engineering, Vol. 48, No. 3 (2013), pp. 300-307 Summary of the Invention [Problem to be solved by the invention]

[0008] The method disclosed in Non-Patent Document 1 has a problem in that the area that can be replicated by roughness replica is limited, and therefore, evaluating a large area requires excessive effort. Furthermore, the method disclosed in Patent Document 1 measures roughness based on a shadow image captured by irradiating a light source, and therefore is not suitable for accurately measuring the shape parameters of a relatively smooth surface.

[0009] Furthermore, when measuring roughness parameters for microscopic roughness on the order of micrometers, the most accurate measurements can be achieved by traversing a laser-type optical displacement meter on an XY stage or the like to ensure mechanical precision.

[0010] However, when such a method is used to measure a wide area, such as the hull of a ship, the traverse device becomes large and heavy, making it difficult to handle at the site for processing, painting, etc. Furthermore, even if the size is increased, there are technical constraints that limit the operating range and measurement range of the traverse device.

[0011] Furthermore, when using an XY stage, a precision stage and stepping motor are required to enable precise movement in the X and Y directions. It is also necessary to provide an XY stage controller to control the XY stage and a controller for the laser displacement meter. This results in a heavy measurement device and high power consumption, making it unsuitable for portability.

[0012] In view of the current situation, the present invention provides a method for quickly, continuously, and directly obtaining surface roughness parameters relating to the three-dimensional surface roughness of non-transportable objects and structures. Ru3 The object of the present invention is to provide a method for evaluating two-dimensional surface roughness. [Means for solving the problem]

[0017] The present invention has been invented to solve the problems in the prior art as described above, The three-dimensional surface roughness evaluation method of the present invention includes: A three-dimensional surface roughness evaluation method for directly measuring the three-dimensional surface roughness of a coating film on an object or structure that cannot be transported, comprising: The two-dimensional laser displacement meter is moved in the X-axis direction by the movement mechanism, and displacement data is obtained by measuring the displacement at regular intervals in the X-axis direction. The displacement data is averaged in the Y-axis direction within a predetermined measurement width that is equal to or less than the laser width of the two-dimensional laser displacement meter to generate reference plane data for each coordinate; by subtracting the reference plane data of each coordinate from the displacement data of each XY plane coordinate, three-dimensional surface roughness data of the measurement object is generated from which eccentricity caused by the wheels or crawlers that are the moving mechanism has been removed; The measurement width of the two-dimensional laser displacement meter is the length in the Y-axis direction to be averaged, before In order to avoid including the surface roughness shape in the reference surface data, The measurement width of the two-dimensional laser displacement meter is known in advance. Measurement target is possible More than twice the average element length RSm 17.6 times or less The present invention is characterized in that: [Effects of the Invention]

[0019] According to the present invention, even if the object to be measured is an object or structure that cannot be transported, it is possible to quickly, continuously, directly and in large quantities obtain surface roughness parameters from the surface of the object to be measured. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram for explaining the configuration of a three-dimensional surface roughness evaluation device in this embodiment. [Figure 2] FIG. 2 is a schematic diagram for explaining the configuration of the three-dimensional surface roughness data acquisition device. [Figure 3] FIG. 3 shows displacement data in the XY plane coordinates when measuring a coated plate 1, which is a metal plate whose surface is painted with paint (covered with a dry paint film; the same applies below). [Figure 4] FIG. 4 shows the reference plane data for each coordinate generated by averaging the displacement data of the XY plane coordinates in FIG. 3 in the Y-axis direction. [Figure 5] FIG. 5 shows the reference plane data obtained by correcting the inclination of the reference plane data shown in FIG. 4 using the least squares method. [Figure 6] FIG. 6 shows three-dimensional surface roughness data obtained by subtracting the reference surface data shown in FIG. 4 from the displacement data shown in FIG. [Figure 7] Figure 7 shows a graph of the analysis results of the surface roughness parameters obtained from the three-dimensional surface roughness data in Figure 6. [Figure 8] Figure 8 is a graph showing the analysis results of the surface roughness parameters obtained for the coated plate 1 as the measurement object using a laser displacement meter attached to an XY stage. [Figure 9] FIG. 9 shows a comparative example of displacement data in XY plane coordinates when a coated plate 1 is used as a measurement object and measurements are taken over a range of 7.5 mm from the end in the Y-axis direction. [Figure 10] FIG. 10 shows reference plane data for each coordinate generated by averaging the displacement data of the XY plane coordinates in FIG. 9 in the Y-axis direction. [Figure 11] FIG. 11 shows the reference plane data obtained by correcting the inclination of the reference plane data shown in FIG. 10 by the least squares method. [Figure 12] FIG. 12 shows three-dimensional surface roughness data obtained by subtracting the reference surface data shown in FIG. 10 from the displacement data shown in FIG. [Figure 13] FIG. 13 is a graph showing the analysis results of the surface roughness parameters obtained from the three-dimensional surface roughness data in FIG. [Figure 14] Figure 14 is a graph showing the relationship between the magnification of the measurement width to the average element length RSm at a measurement width of 32 mm and the ratio (%) of Rz at each measurement width to the maximum height roughness Rz at a measurement width of 32 mm for coated panels 2 to 6. [Figure 15] FIG. 15 is a histogram showing the distribution of surface roughness parameters when the three-dimensional surface roughness of a ship's hull as a measurement object is measured using the three-dimensional surface roughness evaluation device of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments (examples) of the present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic diagram for explaining the configuration of the three-dimensional surface roughness evaluation device in this embodiment, where FIG. 1(a) is a schematic diagram viewed from the side, and FIG. 1(b) is a schematic diagram viewed from the front.

[0022] As shown in Figure 1, the three-dimensional surface roughness evaluation device 10 of this embodiment includes a two-dimensional laser displacement meter 12, a moving mechanism 14, a travel distance reading device 16, a calculation device 18, and a portable battery 20 for operating the two-dimensional laser displacement meter 12, the travel distance reading device 16, and the calculation device 18.

[0023] In addition, when it is not necessary to check the calculation results at the measurement site, as shown in Figure 2, the displacement data acquired by the two-dimensional laser displacement meter 12 and the movement distance data acquired by the movement distance reading device 16 can be stored in a storage device 32 such as a hard disk drive or flash memory, or can be configured to be transmitted to an external terminal such as described later using a communication means 34, and can be used as a three-dimensional surface roughness data acquisition device 30.

[0024] By separating the calculation device 18 in this way and using an external terminal as the calculation device 18, the device configuration at the measurement site can be simplified, and the acquired data can be calculated by an external calculation device such as a personal computer, and the calculation results can be displayed.

[0025] The two-dimensional laser displacement meter 12 is not particularly limited, but for example, a Keyence LJ-V7080 (laser width at the reference distance: 32 mm) or the like can be used. In addition, the two-dimensional laser displacement meter 12 is positioned so that the width direction of the two-dimensional laser displacement meter 12 is perpendicular to the movement direction (X-axis direction) of the movement mechanism 14, i.e., coincides with the Y-axis direction, so that displacement data of the Y-axis coordinate can be read at once at regular intervals.

[0026] Furthermore, in this embodiment, the moving mechanism 14 has two pairs of wheels (i.e., four wheels) that can move only in a predetermined direction (X-axis direction), but is not particularly limited to a mechanism that can move only in a predetermined direction, and may be, for example, a crawler.

[0027] In addition, in this embodiment, a rotary encoder is used as the travel distance reading device 16, and by reading the number of rotations of the wheel, which is the travel mechanism 14, the travel distance is calculated based on the circumference and number of rotations of the wheel.

[0028] The movement distance reading device 16 is not limited to this, and may be, for example, a device that reads the movement distance using a scale sensor with a circular scale linked to the movement mechanism 14.

[0029] Furthermore, as will be described later, the calculation device 18 is not particularly limited as long as it can calculate surface roughness parameters and the like based on the displacement data acquired by the two-dimensional laser displacement meter 12 and the movement distance data acquired by the movement distance reading device 16. For example, it can be configured to transmit the displacement data and the movement distance data to an external terminal such as a tablet computer, a smartphone, or a personal computer, perform calculation processing, and display the calculation results on the external terminal.

[0030] When the calculation device 18 is built into the three-dimensional surface roughness evaluation device 10, a display means for displaying the calculation results such as surface roughness parameters may be provided, or a data output means may be provided so that the calculation results can be transmitted to the above-mentioned external terminal, for example, and displayed on the external terminal.

[0031] The portable battery 20 is not particularly limited, and any existing secondary battery such as a lead storage battery, a nickel-metal hydride secondary battery, or a lithium-ion secondary battery can be used.

[0032] In this embodiment, the three-dimensional surface roughness evaluation device 10 is made easily portable by being equipped with a portable battery 20, but it is also possible to configure the two-dimensional laser displacement meter 12, the computing device 18, etc. to be powered by, for example, an external battery or a commercial power source.

[0033] [Example 1] A specific example of the surface roughness evaluation of the measurement object 22 using the three-dimensional surface roughness evaluation device 10 of this embodiment configured as described above will be described below. First, the three-dimensional surface roughness evaluation device 10 is moved on the surface of the object to be measured 22 by the moving mechanism 14, and movement distance data based on the movement distance obtained by the movement distance reading device 16 at regular intervals and displacement data obtained by the two-dimensional laser displacement meter 12 are recorded in the calculation device 18.

[0034] FIG. 3 shows displacement data in XY plane coordinates measured on a coated plate 1, which is a metal plate having a surface coated with paint, as a measurement object 22. 3 was obtained by using the three-dimensional surface roughness evaluation device 10 of this example to acquire 121 × 121 data points (121 points in both the X-axis and Y-axis directions) at a pitch of 250 μm in a measurement range of 30 mm × 30 mm on the coated plate 1. In this example, such measurements were completed within one second.

[0035] Next, the calculation device 18 averaged the displacement data of the XY plane coordinates in the Y-axis direction to generate reference plane data of each coordinate as shown in FIG.

[0036] The reference plane data obtained by correcting the inclination of the reference plane data shown in Figure 4 using the least squares method is shown in Figure 5. Note that the vertical axis in Figure 5 is enlarged to ±30 μm. Figure 5 shows that the reference plane data includes the eccentricity of the wheels, which are the moving mechanism 14, of approximately ±30 μm.

[0037] 3 includes not only the surface roughness but also the tilt of the measurement object 22 and the eccentricity caused by the rolling of the wheels of the moving mechanism 14, and is therefore not suitable for evaluating surface roughness. Therefore, by using the calculation device 18 to subtract the reference surface data shown in Fig. 4 from the displacement data shown in Fig. 3, the tilt included in the displacement data and the eccentricity caused by the rolling of the wheels of the moving mechanism 14 can be removed, and more accurate three-dimensional surface roughness data can be obtained.

[0038] The three-dimensional surface roughness data thus obtained is shown in FIG. Figure 7 shows the surface roughness parameters Rz (maximum height roughness), RSm (average element length), Rzjis (ten-point mean roughness), Ra (arithmetic mean roughness), Rq (root mean square roughness), Rc (average height of the roughness curve), Rsk (skewness), and Rku (kurtosis) calculated from the three-dimensional surface roughness data shown in Figure 6, and graphed with the minimum displacement point set to zero.

[0039] The coated plate 1 had Rz of 78.9 μm, RSm of 3466 μm, Rzjis of 45.1 μm, Ra of 14.2 μm, Rq of 17.6 μm, Rc of 29.9 μm, Rsk of 0.08, and Rku of 2.7.

[0040] [Comparative Example 1] In order to verify the validity of the surface roughness parameters obtained by the three-dimensional surface roughness evaluation device 10 of this embodiment, the surface roughness parameters were measured in the same range as the measurement range of the painted board 1 in Example 1 using a laser displacement meter (point-type laser displacement meter) attached to an XY stage.

[0041] When measuring a 30 mm × 30 mm measurement range of the measurement object 22 at a pitch of 250 μm using a laser displacement meter attached to an XY stage, as in Example 1, it is necessary to measure 121 points at a pitch of 250 μm in the X-axis direction, then move 250 μm in the Y-axis direction, and then measure 121 points at a pitch of 250 μm in the X-axis direction again, repeating this process. For this reason, in this comparative example, such measurements took about 5 minutes.

[0042] FIG. 8 is a graph showing the calculated surface roughness parameters of the coated panel 1 in Example 1, namely Rz (maximum height roughness), RSm (average element length), Rzjis (ten-point mean roughness), Ra (arithmetic mean roughness), Rq (root mean square roughness), Rc (average height of the roughness curve), Rsk (skewness), and Rku (kurtosis), which were obtained using a laser displacement meter attached to an XY stage.

[0043] The Rz of the coated plate 1 measured using a laser displacement meter was 78.1 μm, RSm was 3561 μm, Rzjis was 50.5 μm, Ra was 13.1 μm, Rq was 16.3 μm, Rc was 35.2 μm, Rsk was −0.11, and Rku was 2.8, which were equivalent to the surface roughness parameters obtained using the three-dimensional surface roughness evaluation device 10 of Example 1.

[0044] Comparative Example 2 To simulate a case where a two-dimensional laser displacement meter with a laser width of 7.5 mm was used as the two-dimensional laser displacement meter 12, surface roughness parameters were measured within a range of 7.5 mm from the end in the Y-axis direction within the measurement range of the coated plate 1 in Example 1. Note that the configuration of the two-dimensional laser displacement meter 12, other than the laser width, was the same as that of the three-dimensional surface roughness evaluation device 10 in Example 1.

[0045] Figure 9 shows displacement data in the XY plane coordinates for coated board 1, obtained by measuring 121 x 31 points (121 points in the X-axis direction and 31 points in the Y-axis direction) at a 250 μm pitch over a measurement range of 30 mm x 7.5 mm.

[0046] As in Example 1, the displacement data of the XY plane coordinates was averaged in the Y-axis direction to generate the reference plane data for each coordinate shown in Fig. 10. Fig. 11 shows the reference plane data after the tilt has been corrected using the least squares method. As in Fig. 5, the eccentricity of the wheels, which are the moving mechanism 14, can be confirmed, but the range of the displacement is larger than in Fig. 5.

[0047] FIG. 12 shows three-dimensional surface roughness data obtained by subtracting the reference surface data shown in FIG. 10 from the displacement data shown in FIG. 9, and removing the tilt contained in the displacement data and the eccentricity caused by the rolling of the wheels of the moving mechanism 14.

[0048] Figure 13 shows the surface roughness parameters Rz (maximum height roughness), RSm (average element length), Rzjis (ten-point mean roughness), Ra (arithmetic mean roughness), Rq (root mean square roughness), Rc (average height of the roughness curve), Rsk (skewness), and Rku (kurtosis) calculated from the three-dimensional surface roughness data shown in Figure 12, and graphed with the minimum displacement point set to zero.

[0049] The coated plate 1 measured in Comparative Example 2 had Rz of 56.3 μm, RSm of 3900 μm, Rzjis of 34.9 μm, Ra of 10 μm, Rq of 12.4 μm, Rc of 24.9 μm, Rsk of 0.09, and Rku of 2.8.

[0050] In Comparative Example 2, the surface roughness parameters related to roughness height, such as Rz, Rzjis, Ra, Rq, and Rc, are smaller than those in Example 1 and Comparative Example 1. This is because the surface roughness shape is included in the reference surface data averaged in the width direction (Y-axis direction) of the two-dimensional laser.

[0051] Furthermore, it is thought that if the measurement width of the two-dimensional laser displacement meter 12 (7.5 mm, the laser width, in Comparative Example 2), which is the length in the Y-axis direction to be averaged, is too small compared to the RSm (average length of the elements) of the measurement object 22 (3900 μm = 3.9 mm in Comparative Example 2), the roughness height will be underestimated.

[0052] In order to properly evaluate the roughness height, it is preferable that the length in the Y-axis direction to be averaged (the measurement width of the two-dimensional laser displacement meter 12) be at least twice the RSm of the measurement object 22. Below, the relationship between the measurement width of the two-dimensional laser displacement meter 12 and the average length RSm of the elements of the measurement object 22 is examined.

[0053] [Example 2] Table 1 shows the surface roughness parameters obtained by measuring a painted plate 2, which was a metal plate with its surface painted with paint as the measurement object 22, and changing the measurement width of the two-dimensional laser displacement meter 12 to 0.5 mm, 1 mm, 2 mm, 4 mm, 16 mm, and 32 mm, and correcting using reference surface data averaged in the width direction (Y-axis direction) of the two-dimensional laser for each measurement width.

[0054] [Table 1]

[0055] As shown in Table 1, the surface parameters Rz, Rzjis, Ra, Rq, and Rc related to the roughness height become smaller as the measurement width becomes smaller. This is because the smaller the measurement width, the more the amount of surface roughness shape included in the reference surface data averaged in the width direction (Y-axis direction) of the two-dimensional laser displacement meter 12 becomes.

[0056] Furthermore, it was revealed that as the measurement width increases, the surface parameters related to roughness height, Rz, Rzjis, Ra, Rq, and Rc, all tend to converge to their true values. This is because when the measurement width becomes sufficiently larger than RSm, the surface roughness shape is no longer included in the reference surface data averaged in the width direction (Y-axis direction) of the two-dimensional laser.

[0057] The maximum height roughness Rz at a measurement width of 32 mm is 111.8 μm, and the average element length RSm is 3325 μm. Table 2 shows the magnification of each measurement width in Table 1 relative to RSm (3325 μm) at a measurement width of 32 mm, and the ratio of each surface roughness parameter at each measurement width in Table 1 relative to each surface roughness parameter at a measurement width of 32 mm.

[0058] [Table 2]

[0059] The ratio of Rz at each measurement width to Rz at a measurement width of 32 mm was 33.7% when the magnification of the measurement width to RSm at a measurement width of 32 mm was 0.2x, 57.7% at 0.3x, 81.7% at 0.6x, 95.2% at 1.2x, 101.2% at 2.4x, and 104.4% at 4.8x.There is a clear tendency for Rz to converge to 100% as the magnification of the measurement width to RSm increases.In particular, it converges to almost 100% when the measurement width is about twice RSm.

[0060] When measuring an object 22 whose surface roughness shape is unknown, the measurement width of the two-dimensional laser displacement meter 12 can be varied in this manner, and a range of the measurement width with little variation in each surface roughness parameter can be selected as the effective measurement width.

[0061] Below, similar measurements were taken on painted plates 3 to 6, which were metal plates with their surfaces painted with paint, as the measurement object 22, and the measurement width of the two-dimensional laser displacement meter 12 was changed to 0.5 mm, 1 mm, 2 mm, 4 mm, 16 mm, and 32 mm.The roughness evaluation results obtained by correcting the data using the reference surface averaged in the width direction (Y-axis direction) of the two-dimensional laser for each measurement width are shown in Tables 3, 5, 7, and 9, respectively.

[0062] The maximum height roughness Rz of coated plate 3 at a measurement width of 32 mm was 60.4 μm, and the average element length RSm was 1820 μm. The maximum height roughness Rz of coated plate 4 at a measurement width of 32 mm was 146.3 μm, and the average element length RSm was 2200 μm. The maximum height roughness Rz of coated plate 5 at a measurement width of 32 mm was 76.5 μm, and the average element length RSm was 4150 μm. The maximum height roughness Rz of coated plate 6 at a measurement width of 32 mm was 112.3 μm, and the average element length RSm was 5001 μm.

[0063] Table 4 shows the magnification of each measurement width in Table 3 relative to RSm (3325 μm) at a measurement width of 32 mm, and the ratio of each surface roughness parameter at each measurement width in Table 3 relative to each surface roughness parameter at a measurement width of 32 mm.Similarly, Table 6 is for Table 5, Table 8 is for Table 7, and Table 10 is for Table 9.

[0064] [Table 3]

[0065] [Table 4]

[0066] [Table 5]

[0067] [Table 6]

[0068] [Table 7]

[0069] [Table 8]

[0070] [Table 9]

[0071] [Table 10]

[0072] The roughness evaluation results for all painted panels 3 to 6 clearly tend to converge to 100% as the magnification of the measurement width relative to RSm increases, and it is particularly clear that they converge to almost 100% when the measurement width is about twice the RSm.

[0073] Figure 14 is a graph showing the relationship between the magnification of the measurement width to the average element length RSm at a measurement width of 32 mm and the ratio (%) of Rz at each measurement width to the maximum height roughness Rz at a measurement width of 32 mm for coated panels 2 to 6.

[0074] As shown in FIG. 14, for all of coated plates 2 to 6, when the measurement width was set to about twice RSm or more, the ratio of Rz converged to 100% and did not fluctuate significantly.

[0075] This revealed that if the measurement width of the two-dimensional laser displacement meter 12 is at least twice the average length RSm of the elements of the measurement object 22, the possibility of the surface roughness shape being included in the reference surface data averaged in the width direction (Y-axis direction) of the two-dimensional laser is reduced, and accuracy can be ensured.

[0076] When using the three-dimensional surface roughness evaluation device 10 of the present invention to measure the surface roughness parameters of a measurement object 22 having unknown roughness, it is also effective to evaluate the average length RSm of the elements of the measurement object 22 in advance, for example, using a conventional method such as that described above.

[0077] Furthermore, if the average length RSm of the elements of the measurement object 22 cannot be evaluated in advance, as described above, the measurement width of the two-dimensional laser displacement meter 12 can be changed to set the range in which there is no significant variation in each surface roughness parameter as the effective measurement width range, thereby enabling highly accurate surface roughness evaluation.

[0078] [Example 3] Using a three-dimensional surface roughness data acquisition device 30 and a computing device 18, which is an external terminal, the three-dimensional surface roughness of a ship's hull was measured as the measurement object 22. The configuration of the three-dimensional surface roughness data acquisition device 30 of Example 3 is the same as that of the three-dimensional surface roughness evaluation device 10 of Example 1, with the computing device 18 omitted. Figure 15(a) is a three-dimensional histogram showing the distribution of Rz (maximum height roughness) and RSm (average element length), which are surface roughness parameters of a ship's hull measured using a three-dimensional surface roughness data acquisition device 30; Figure 15(b) is a histogram showing the distribution of the RSm component of Figure 15(a); and Figure 15(c) is a histogram showing the distribution of the Rz component of Figure 15(a).

[0079] After the hull painting was completed, the three-dimensional surface roughness data acquisition device 30 was used to scan 27 cm in the X-axis direction, acquiring nine 30 mm x 30 mm pieces of data, and repeating this process until 100 measurements were taken across the entire hull, acquiring 900 pieces of data.

[0080] The measurements of 100 locations were completed in approximately two hours. Of the total 900 measurement points, valid data was obtained for 620 points after excluding measurement errors, etc., and the acquired data was processed by the external terminal, arithmetic unit 18, resulting in a surface roughness parameter of Rz (maximum height roughness) of 50.7 μm and RSm (average element length) of 3187 μm.

[0081] In addition, the Rz distribution in the three-dimensional histogram shown in FIG. 15 was from 20 μm to 140 μm, and the RSm distribution was from 1750 μm to 7500 μm. [Explanation of symbols]

[0082] 10 Three-dimensional surface roughness evaluation device 12 Two-dimensional laser displacement sensor 14 Moving mechanism 16 Travel distance reading device 18 Arithmetic unit 20 Portable battery 22 Measurement Object 30 Three-dimensional surface roughness data acquisition device 32 Storage device 34 Means of communication

Claims

[Claim 1] A three-dimensional surface roughness evaluation method for directly measuring the three-dimensional surface roughness of a coating film on an object or structure that cannot be transported, comprising: The two-dimensional laser displacement meter is moved in the X-axis direction by a movement mechanism, and displacement data is obtained by measuring displacement at regular intervals in the X-axis direction. The displacement data is averaged in the Y-axis direction within a predetermined measurement width that is equal to or less than the laser width of the two-dimensional laser displacement meter to generate reference plane data for each coordinate; by subtracting the reference plane data of each coordinate from the displacement data of each X-Y plane coordinate, three-dimensional surface roughness data of the measurement object is generated from which eccentricity caused by the wheels or crawlers that are the moving mechanism has been removed; The measurement width of the two-dimensional laser displacement meter is the length in the Y-axis direction to be averaged, A three-dimensional surface roughness evaluation method characterized in that the measurement width of the two-dimensional laser displacement meter is set to be between 2 and 17.6 times the average length RSm of the elements that the measurement object can take, which is known in advance, so that the surface roughness shape is not included in the reference surface data.

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