Method for measuring shape

Abstract

To enable accurate measurement of the shape of a measurement target even when a shape measuring machine is affected by vibration or external light.SOLUTION: The method for measuring a shape includes: installing a rotary laser measuring device 2 at a measurement position; adjusting the rotational speed of the laser measuring device such that the integer multiple of a period of displacement of the laser measuring device equals the rotational period of the laser measuring device; substituting an actually measured distance b and a measurement interval ω obtained when the laser measuring device makes one full rotation into a relational expression to form a plurality of linear equations; and solving the simultaneous linear equations to obtain the corrected distance x. In this way, a corrected distance with small variation and high resolution is calculated.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention can also be used to measure the shape of interior partition walls of real estate, the shape of the exterior of real estate, or the shape of large industrial products. The present invention relates to a shape measuring instrument that can accurately measure the shape of a structure (hereinafter simply referred to as the structure) that can be viewed from the measurement position by irradiating the structure with laser light from the measurement position and measuring the distance from the measurement position to the structure based on the time it takes for the reflected light to return. The laser measuring device is installed at the measurement position and can be rotated to accurately measure the shape of the structure. [Background technology]

[0002] When a laser measurement device is used for the length measurement function, a shape measurement machine that can measure the distance between the structure and the length measurement function by irradiating laser light and measuring the time it takes for the light to hit the structure to be measured and bounce back, and then generate a three-dimensional point cloud of the structure by rotating this laser measurement device, is available as existing technology.

[0003] However, with this existing technology, when attached to a moving object such as a drone or automobile, if the installed laser measurement device is displaced due to vibrations of the moving object, even if the moving object is not moving, this displacement can have a negative effect on the shape measurement results. Also, there is a drawback in that the measurement length can vary due to the influence of ambient light.

[0004] As an improvement measure for measuring the shape of a structure accurately, it is possible to calculate the position and attitude of the shape measuring device over time using satellite positioning data from a receiver and inertial measurement data from an inertial measurement unit, as in the invention described in Patent Document 1, JP 2023-095252 A. However, this requires a receiver and an inertial measurement unit, which poses a problem of high costs. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-095252 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem that the present invention aims to solve is to enable more accurate measurement of the shape of an object by suppressing the drawback of measurement errors in shape and dimensions occurring when vibrations occur at the measurement position or when the measurement position is affected by ambient light. [Means for solving the problem]

[0007] The configuration of the present invention that solves this problem is as follows: 1) A method for accurately measuring the shape of a structure in which one or more structural members are arranged in a ring shape around the periphery of a predetermined space, and the surface of the structural member facing the space is a diffuse reflection surface, and the structure or a laser measurement device is displaced relatively due to vibration or shaking, the method being carried out in the following steps 1, 2, and 3: Step 1: A laser measuring device is installed in the space, which can project a laser beam from a laser projector of the laser measuring device toward the object to be measured, receive reflected light from the projection spot on the object to be measured, measure the actual distance b from the projection position of the laser projector to the projection spot position, and store and output these values; Step 2: The laser projection direction of the installed laser measurement device is rotated 360° or multiple times m (0 to 360° × m) at measurement intervals ω, and the actual measured distance b m (kω)k=1,2,3···n m=1,2,3··· is measured, and the projection angles kω, k=1,2,3···n and the measured distance b at that time are stored in a computer-based storage calculation unit. m (kω)k=1,2,3···nm=1,2,3··· and memorize them Step 3: The actual distance b stored in the memory calculation unit m(kω)k=1,2,3···n nm=1,2,3···, and the data of kω k=1,2,3···n are substituted into the formula (7) below stored in the memory calculation unit, and the multiple simultaneous linear equations (7) below with the data substituted are solved to output the corrected distance x(kω)k=1,2,3···n and projection angle kω k=1,2,3···n that show the shape of the structure in the polar coordinate system.

number

[0008] In the present invention, a laser measuring device is used that has the function of changing the projection direction of the laser light so that it rotates, and that can measure the distance from the projected wave and received wave to the projection spot position, and the laser beam is rotated by ω° per revolution, n=360° / ω° times. The actual measured distance b m (kω)k= 1,2···n can be obtained, and this holds true assuming that the shape of the structure remains unchanged. A simultaneous linear equation is created by substituting ω, kω, b(kω-ω), b(kω), and b(kω+ω) into the relational equation x(kω-ω)-2Cos(ω)x(kω)+x(kω+ω)=b(kω-ω)-2Cos(ω)b(kω)+b(kω+ω), and by solving this simultaneous linear equation using a computer-based memory calculation unit, the corrected distance x(kω)k=1,2···n is obtained, and the shape of the structure is calculated using the corrected distance x. In the present invention, in order to obtain the measured distance b, the period of displacement of the laser measurement device is TIFF2025155454000005.tif10150b1(kω)} 2 Set the projection angular velocity dω / dt and measurement interval ω of the laser measurement device so that is minimized. Here, the measured distance on the first lap is b1(kω)k=1,2···n, and the measured distance on the second lap is b2(kω)k=1,2···n. In the present invention, the projection angle of the laser measurement device is the mth rotation, and the correction distance when the laser measurement device is positioned at a projection angle kω is expressed as χ m (kω), the variation is small and high It is characterized by outputting TIFF2025155454000006.tif11152, where j is any positive number. [Effects of the Invention]

[0009] In this way, the specific numerical values ​​and shape of the structure can be determined from the point cloud of the polar coordinate values ​​of the corrected distance x(kω) k=1,2,3···n and the projection angle kω k=1,2,3···n. This corrected distance x is a shape expression that corrects the actual measured distance b(kω)k=1,2,3···n of the laser measurement device, reducing the effects of displacement and vibration of the laser measurement device. TIFF2025155454000007.tif10153This will help avoid variations caused by ambient light. Therefore, the shape measuring instrument of the present invention has the advantage that it can obtain an accurate shape of a structure while eliminating the influence of vibrations and ambient light on the installed laser measuring device. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram showing a situation in which a shape is measured using a shape measuring machine in an embodiment of the present invention. [Figure 2] FIG. 2 is an explanatory diagram showing that the actual measured distance in the first revolution overlaps with the actual measured distance in the second revolution as a result of adjusting the projection angular velocity of the laser measurement device 2 with a distance measurement function of the embodiment. [Figure 3] FIG. 3 is an explanatory diagram showing the relationship between the measured distance b(kω) and the corrected distance x(kω) in which the influence of displacement is eliminated in the embodiment. [Figure 4] FIG. 4 is an explanatory diagram showing the relationship between the measured distance b(kω-ω) and the corrected distance x(kω-ω) in which the influence of displacement is eliminated in the embodiment. [Figure 5] FIG. 5 is an explanatory diagram showing the relationship between the measured distance b(kω+ω) and the corrected distance x(kω+ω) in which the influence of displacement is eliminated in the embodiment. [Figure 6] FIG. 6 is a process flow diagram up to shape calculation showing the work procedure and calculation processing steps up to shape calculation in the embodiment. [Figure 7] FIG. 7 is a comparison diagram between (a) the shape of a structure displayed using the measured distance b(ω) obtained using a displaced shape measuring instrument and (b) the shape of a structure displayed using the corrected distance x(ω) obtained using an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] In the present invention, a practical angle for the measurement interval ω° is approximately 0.125°, but for simplicity, the illustrated embodiment will be described as having a measurement interval ω° = 30°. In this case, k = 1, 2, 3... n = 12, and 12 measurements are taken every 30° during one rotation. [Example]

[0012] 1 to 5 are explanatory diagrams showing how the shape of a surrounding structure is measured using a shape measuring instrument 1 of the present invention. In this example, ω°=30°, n=12, and m=2.

[0013] When the shape measuring instrument 1 of the embodiment uses a laser measuring device 2 for the length measurement function, as the laser measuring device 2 makes one revolution (measuring n=360° / ω° times at ω° intervals), it is affected by vibrations and ambient light, resulting in an inaccurate measured distance b(kω)k=1,2···n.

[0014] First, the integral multiple of the displacement period of the laser measurement device 2 and the rotation of the laser measurement device 2 TIFF2025155454000008.tif11153 The projection angular velocity dω / dt of the laser measurement device 2 is adjusted so that the measured distance in the first round and the measured distance in the second round are the same as shown in Figure 2. Here, the measured distance in the first round is b1(kω)k=1,2···n, and the measured distance in the second round is Let b2(kω)k=1,2···n. Then the following relation holds for all projection angles.

[0015] Using the relational expression x(kω-ω)-2Cos(ω)x(kω)+x(kω+ω)=b(kω-ω)-2Cos(ω)b(kω)+b(kω+ω), the correction distance x(kω)k= 1, 2···n is calculated. The derivation of the relational expression will be described later. The actual distance measured by the laser measurement device 2, b(kω)k= By substituting 1.2···n and the measurement interval ω, the following simultaneous linear equations can be formulated.

[0016]

number

[0017] Therefore, the corrected distance x(kω)k=1,2···n, which eliminates the influence of displacement, can be obtained from the following equation.

number

[0018] Finally, the corrected distance when the projection angle of the laser measurement device 2 is the mth rotation and the laser measurement device 2 is positioned at a projection angle kω is expressed as x m(kω), the variation is small, TIFF2025155454000011.tif11155, where j is any positive number.

number

[0019] Here, the derivation of the relational expression will be explained.

[0020] When the laser measurement device 2 is positioned at a projection angle kω, the laser measurement device 2 ε x (kω), ε y If the distance is displaced by (kω), the relationship between the measured distance b(kω) and the corrected distance x(kω) that eliminates the influence of the displacement is as shown in FIG. 3, and the following equation 4 holds.

[0021]

number

[0022]

number

[0023]

number

[0024] From the above three equations, ε x (kω) and ε y By eliminating (kω), we can derive the following relational expression (7). These calculations are carried out by a memory calculation unit 8 using a computer to which data has been input, and the shape of the structure 7 is calculated.

number

[0025] In the examples, a laser measuring device was used as the length measurement function of the shape measuring machine, but the invention can also be applied to other length measurement functions. Furthermore, while the focus was on vibrations of the shape measuring machine, other displacements are also included. Furthermore, while the focus was on variations due to ambient light, variations due to other influences are also included. [Explanation of symbols]

[0026] 1 Shape measuring machine 2. Laser measurement equipment 3. Laser light 4 Reflected light 7 Structure 8 Computer-based memory calculation section b) Distance from the laser projection position of the laser measurement device to the position of the object to be measured

Claims

1. A measurement method for accurately measuring the shape of a structure in which one or more structural members are arranged in a ring shape to surround the outer periphery of a specified space, and the surfaces of the structural members facing the space are diffusely reflective surfaces, and the structure or a laser measurement device is displaced relatively due to vibration or shaking, the shape measurement method being carried out in the following order of steps 1, 2, and 3. Step 1: A laser measuring device is installed in the space, which can project laser light from a laser projector of the laser measuring device toward a measurement object, receive reflected light from a projection spot on the measurement object, measure an actual distance b from the projection position of the laser projector to the projection spot position, and store and output these values; Step 2: The laser projection direction of the installed laser measurement device is rotated 360° or multiple times m (0 to 360° × m) at measurement intervals ω, and the actual measured distance b ｍ (kω) k = 1, 2, 3 ... n m = 1, 2, 3 ... are actually measured, and the projection angles kω, k = 1, 2, 3 ... n and the actual measured distance b at that time are stored in a storage calculation unit using a computer. ｍ (kω) k=1, 2, 3 . . . n m=1, 2, 3 . Step 3: The actual distance b stored in the memory calculation unit ｍ (kω)k=1,2,3...n m=1,2,3..., the data of kωk=1,2,3...n is substituted into the formula of the following formula 7 stored in the storage calculation unit, and the multiple simultaneous linear equations of the following formula 7 into which the data has been substituted are solved, so that the corrected distance x(kω)k=1,2,3...n and the projection angle kωk=1,2,3...n which indicate the shape of the structure in the polar coordinate system can be output. [Equation 7]

2. Before moving from step 1 to step 2, in order to make the integral multiple of the period of the displacement acting on the laser measurement device equal to the rotation period of the laser measurement device, The value of the measurement interval ω is determined, and the actual measured distance b using the determined measurement interval ω is calculated. ｍ 2. A shape measurement method according to claim 1, wherein the corrected distances x(kω)k=1, 2, 3...n and projection angles kωk=1, 2, 3...n that indicate the shape of the structure in a polar coordinate system are output by solving Equation 7 using (kω).

3. The projection angle of the laser measurement device is the mth rotation, and the correction distance when the laser measurement device is positioned at a projection angle kω is x ｍ (kω), the variation is small and the resolution is high.

3. The shape measuring method according to claim 1, wherein the measurement is performed by the method.

Images