Slope displacement monitoring method

Abstract

The invention provides a slope displacement monitoring method, and relates to the technical field of large-range slope displacement measurement. Comprising the steps that a plurality of measuring points, a plurality of datum points and monitoring equipment are arranged in a slope area to be measured; respectively calculating the displacements of the plurality of measuring points in the vertical direction and the horizontal direction, and respectively obtaining the relative displacement variations between the plurality of measuring points and the reference point in the vertical direction and the horizontal direction; and calculating displacement transmission error correction values of the plurality of measuring points in the vertical direction and the horizontal direction, and correcting relative displacement variation of the plurality of measuring points in the vertical direction and the horizontal direction. According to the invention, complete coverage of the high-resolution image on the side slope measurement area can be realized, and data support is provided for high-precision side slope displacement measurement; in addition, multi-measuring-point transmission type measurement is achieved through rotation imaging, an effective solution is provided for displacement transmission errors, and large-range slope high-precision displacement measurement based on monitoring ball machine rotation type imaging is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of large-scale slope displacement measurement, and in particular to a slope displacement monitoring method suitable for monitoring rotary imaging of a ball camera. Background Art

[0002] The surveillance ball camera with a rotating mechanism, with its unique rotating imaging technology, can theoretically greatly expand the monitoring field of view and realize comprehensive, real-time capture and accurate monitoring of displacement changes in a wide slope area. This technology is of great significance for timely warning of natural disasters such as landslides and debris flows, as well as for assessing slope stability. However, in the actual deployment and operation process, this method faces a series of technical challenges and environmental limitations, which seriously affect its effective application in the field of high-precision, large-scale slope monitoring.

[0003] First, the lack of stability of the surveillance camera is an urgent problem to be solved. Since the slope monitoring environment is often complex and changeable, including the influence of natural factors such as wind and vibration, the surveillance camera must be able to withstand various external forces and remain stable after installation to ensure that the imaging quality is not affected. Some surveillance cameras on the market currently fail to fully consider these extreme conditions in their design, resulting in shaking in actual applications, which in turn affects the accuracy of monitoring data.

[0004] Secondly, the low repeatability of the rotating mechanism is also a key factor that restricts its application. For slope monitoring, accurate repeatability means being able to accurately photograph the same area multiple times, thereby identifying small displacement changes through time series analysis. However, due to mechanical wear and control algorithm accuracy limitations, the existing rotating mechanism is difficult to achieve long-term stable high-precision positioning, which directly reduces the reliability and effectiveness of monitoring data.

[0005] In addition, the complex environment of the slope deformation area poses a huge challenge to the layout of the benchmarks. The slope terrain is complex, and vegetation coverage, exposed rocks, loose soil and other conditions are common. These factors make it extremely difficult to find and set up stable benchmarks. The lack of stable benchmarks will directly affect the accuracy of subsequent processing steps such as image stitching and coordinate conversion, thereby reducing the accuracy of the entire monitoring system.

[0006] Finally, the existing image stitching algorithms also face the problems of image accuracy loss and geometric distortion when processing images captured by rotating surveillance cameras. Since the image rotation is inevitable during the rotation of the surveillance camera, it is difficult to perfectly align the captured images when stitching, resulting in stitching seams, image distortion, etc. These algorithmic deficiencies further limit the application potential of rotating surveillance cameras in high-precision slope monitoring. Summary of the invention

[0007] In order to solve the deficiencies in the prior art, the present invention proposes a slope displacement monitoring method. The method only requires the deployment of reference points in the peripheral stable areas on both sides of the slope, and realizes multi-point transfer measurement by rotation imaging, and proposes an effective solution for displacement transfer errors, realizing high-precision displacement measurement of a large range of slopes based on rotation imaging of a monitoring ball camera.

[0008] The present invention provides a slope displacement monitoring method, comprising the following steps:

[0009] Step 1: Set up several measuring points, several benchmark points and monitoring equipment in the slope area to be measured;

[0010] Step 2: Calculate the displacement of several measuring points in the vertical direction based on the reference point, and obtain the relative displacement changes between the several measuring points and the reference point in the vertical direction;

[0011] Step 3: Calculate the displacement transmission error correction values ​​of several measuring points in the vertical direction, and correct the relative displacement changes of several measuring points in the vertical direction based on the displacement transmission error correction values ​​of several measuring points in the vertical direction;

[0012] Step 4: Using the same method as steps 2 and 3, the relative displacement changes between several measuring points and the reference point in the horizontal direction are obtained respectively, and the relative displacement changes of several measuring points in the horizontal direction are corrected respectively based on the displacement transfer error correction values ​​of the several measuring points in the horizontal direction.

[0013] Furthermore, the specific process of setting a number of measuring points, a number of reference points and monitoring equipment is as follows:

[0014] In the deformation area of ​​the slope to be measured, n measuring points are set in sequence from left to right in an intermittent manner. The n measuring points are counted as (c1,…,c n / 2 ,…,c n );

[0015] A first reference point J1 and a second reference point J2 are respectively set on both sides of the deformation area of ​​the slope to be measured;

[0016] The monitoring equipment is arranged in the middle of the deformation area of ​​the slope to be measured.

[0017] Furthermore, the specific method for obtaining the relative displacement changes between several measuring points and the reference point in the vertical direction is as follows:

[0018] S2.1. Using monitoring equipment, the image coordinates of n measurement points, the first reference point J1, and the second reference point J2 are collected in sequence from left to right to obtain a group E of images;

[0019] Wherein, E is a natural number greater than or equal to 1;

[0020] S2.2, respectively calculating the image spacing between each point in the E group of images in the vertical direction to obtain the e group of image spacings; wherein each point includes n measurement points, a first reference point J1 and a second reference point J2; e = (1, 2, ..., E);

[0021] S2.3, calculating the relative displacement change between each measuring point and the reference point in the second group of images based on the first group of image spacing and the second group of image spacing;

[0022] Calculate the relative displacement change between each measuring point and the reference point in the third group of images based on the spacing between the first group, the second group, and the third group of images;

[0023] In this way, the relative displacement changes between each measuring point and the reference point in the E group of images are calculated one by one.

[0024] Furthermore, the corrected displacement of the first measuring point c1 in the vertical direction is calculated The specific process is as follows:

[0025] From the first reference point J1 to the middle measuring point c of the slope to be measured n / 2 Transfer and get the measurement point c n / 2 The first displacement

[0026]

[0027] From the second reference point J2 to the middle measuring point c of the slope to be measured n / 2 Transfer and get the measurement point c n / 2 The second displacement

[0028]

[0029] Let the first displacement and the second displacement The cumulative error between the first reference point J1 and the first measuring point c1 is f, and the number of times the first reference point J1 is transferred to the first measuring point c1 is 1. Then the error transfer correction value Δc1 of the first measuring point c1 is:

[0030]

[0031] Where: m L is the middle measuring point c of the slope to be measured from the first reference point J1 n / 2 The total number of transfers made;

[0032] Then the corrected displacement of the first measuring point c1 in the vertical direction is for:

[0033]

[0034] Furthermore, the corrected displacement of the first measuring point c1 in the vertical direction is calculated as follows: The specific process is the same as the steps of the method, and the corrected displacements of other measuring points in the vertical direction and the corrected displacements of the measuring points in the horizontal direction are calculated one by one.

[0035] Furthermore, the first reference point J1 is measured toward the middle point c n / 2 Transfer or from the second reference point J2 to the intermediate measurement point c n / 2 During the transfer, the first measuring point c1 to the intermediate measuring point c n / 2 Each measurement point between or the nth measurement point c n To the middle measuring point c n / 2 The specific process of the displacement transfer error correction value of each measuring point in the vertical direction is as follows:

[0036] S3.1, measure from the first reference point J1 to the middle point c n / 2 And from the second reference point J2 to the middle measurement point c n / 2 Transfer, respectively get from the first reference point J1 to the middle measurement point c n / 2 The first displacement transferred And from the second reference point J2 to the middle measurement point c n / 2 The second displacement transmitted

[0037] S3.2, from the first reference point J1 to the middle measurement point c n / 2 The cumulative error f of transmission is:

[0038]

[0039] The cumulative error f is the error from the first reference point J1 to the intermediate measurement point c. n / 2 or, from the second reference point J2 to the intermediate measurement point c n / 2 The cumulative error of transmission;

[0040] Then from the first reference point J1 to the middle measurement point c n / 2 During the transfer, the first measuring point c1 to the intermediate measuring point c n / 2 The error transfer correction number Δ of the displacement of each measuring point between is:

[0041]

[0042] Where m is the number of displacement calculation transfers corresponding to the measurement point, m LFrom the first measuring point c1 to the middle measuring point c n / 2 The total number of displacement calculation passes;

[0043] S3.3, then the error transfer correction Δc1 of the displacement of the first measuring point c1 is:

[0044]

[0045] From the first measuring point c1 to the middle measuring point c n / 2 Displacement transmission error correction value setting for:

[0046]

[0047] S3.4, repeat step S3.3, and measure from the first measuring point c1 to the middle measuring point c n / 2 The displacement transfer error correction values ​​of the remaining measuring points in the vertical direction are calculated one by one;

[0048] S3.5, let the nth measurement point c n To the middle measuring point c n / 2 The calculation formula of the error transfer correction number Δ′ is:

[0049]

[0050] Among them, m R is the nth measurement point c n To the middle measuring point c n / 2 The total number of displacement calculation passes;

[0051] Then the nth measurement point c n The error transfer correction factor Δc of the displacement n for:

[0052]

[0053] From the nth measuring point c n To the middle measuring point c n / 2 Displacement transmission error correction value setting for:

[0054]

[0055] S3.6, repeat step S3.5, for the nth measuring point c n To the middle measuring point c n / 2 The displacement transfer error correction values ​​of the remaining measuring points in the vertical direction are calculated one by one.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The present invention proposes a scheme for imaging monitoring of several reference points and several deformation measurement points of a slope to be inspected based on a rotating monitoring device, so as to achieve complete coverage of the slope measurement area with high-resolution images, and provide data support for high-precision slope displacement measurement; and only needs to arrange reference points in the peripheral stable areas on both sides of the slope to achieve multi-point transfer measurement by rotating imaging, and proposes an effective solution for displacement transfer errors, thereby achieving high-precision displacement measurement of a large range of slopes based on rotating imaging of a monitoring ball camera.

[0058] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0060] Figure 1 It is a schematic diagram of the principle of a slope displacement monitoring method in an embodiment of the present invention. DETAILED DESCRIPTION

[0061] In order to make the above-mentioned purposes, features and advantages of the present invention more clear and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings. It should be noted that the drawings of the present invention are all simplified and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the implementation of the present invention; the "number" mentioned in the present invention is not limited to the specific number in the examples in the accompanying drawings; the directions or positional relationships indicated by "front", "middle", "back", "left", "right", "up", "down", "top", "bottom", "middle", etc. mentioned in the present invention are based on the directions or positional relationships shown in the drawings of the present invention, and do not indicate or imply that the devices or components referred to must have a specific direction, nor can they be understood as limitations on the present invention.

[0062] Example:

[0063] See also Figure 1 As shown, a slope displacement monitoring method provided by the present invention comprises the following steps:

[0064] Step 1: Set up several measuring points, several reference points and a monitoring ball camera in the slope area to be measured.

[0065] The specific process is as follows:

[0066] Several measuring points are arranged in the deformation area of ​​the slope to be measured according to the monitoring requirements, and the measuring points are named from left to right as the first measuring point c1, the second measuring point c2, ..., the middle measuring point c n / 2 , ..., nth measurement point c n ;

[0067] A reference point is arranged in the relatively stable areas on both sides of the slope to be measured, and the two reference points are named the first reference point J1 and the second reference point J2 respectively;

[0068] A monitoring ball camera is arranged in the middle part of the slope to be measured. Due to the contradiction between the observation field and resolution of the monitoring ball camera (preferably a monitoring ball camera for outdoor visible light imaging), one imaging cannot completely cover the entire area of ​​the slope to be measured (including the deformation area and the stable area) under the premise of ensuring high image resolution. Therefore, in the present invention, the imaging focal length of the monitoring ball camera is set to an equivalent focal length of 75mm. Under this imaging condition, the image resolution is high and can meet the measurement accuracy requirements. Then, the ball camera is rotated from left to right with the help of a rotating mechanism, and photos are collected at fixed angle intervals, such as Figure 1 As shown, the complete coverage of the slope measurement area by high-resolution images is finally achieved.

[0069] Step 2: Calculate the displacement of several measuring points in the vertical direction based on the reference point, and obtain the relative displacement changes between the several measuring points and the reference point in the vertical direction.

[0070] The specific process is as follows:

[0071] S2.1. Using monitoring equipment, the image coordinates of n measurement points, the first reference point J1, and the second reference point J2 are collected in sequence from left to right to obtain a group E of images;

[0072] Where E is a natural number greater than or equal to 1; and two adjacent groups of images partially overlap, the overlapping area must contain at least two identical measurement points, and the number of image acquisition groups is based on the ability to cover the entire measurement area.

[0073] S2.2, respectively calculating the image spacing between each point in the E group of images in the vertical direction to obtain the e group of image spacings; wherein each point includes n measurement points, a first reference point J1 and a second reference point J2; e = (1, 2, ..., E);

[0074] S2.3, calculating the relative displacement change between each measuring point and the reference point in the second group of images based on the first group of image spacing and the second group of image spacing;

[0075] Calculate the relative displacement change between each measuring point and the reference point in the third group of images based on the spacing between the first group, the second group, and the third group of images;

[0076] In this way, the relative displacement changes between each measuring point and the reference point in the E group of images are calculated one by one.

[0077] Specifically, the first set of image coordinates are: The first set of image coordinates of the first reference point J1 is The first set of image coordinates of the second reference point J2 is: The first set of image coordinates of the first measurement point c1 is The first set of image coordinates of the second measurement point c2 is The first set of image coordinates of the third measurement point c3 is: Middle measuring point c n / 2 The first set of image coordinates The nth measuring point c n The first set of image coordinates is

[0078] The second set of image coordinates are: The second set of image coordinates of the first reference point J1 are: The second set of image coordinates of the second reference point J2 is: The second set of image coordinates of the first measurement point c1 is The second set of image coordinates of the second measurement point c2 is The second set of image coordinates of the third measurement point c3 is: Middle measuring point c n / 2 The second set of image coordinates The nth measuring point c n The second set of image coordinates is

[0079] but:

[0080] ①, the first set of displacement distances between the first reference point J1 and the first measuring point c1 in the vertical direction for:

[0081]

[0082] The first set of displacement distances between the first measuring point c1 and the second measuring point c2 in the vertical direction for:

[0083]

[0084] The remaining two adjacent measurement points and the nth measurement point c n The first set of displacement intervals between the second reference point J2 in the vertical direction are calculated one by one in the same manner as described above.

[0085] ②, the relative displacement change between the first measuring point c1 and the first reference point J1 for:

[0086]

[0087] The relative displacement change between the second measuring point c2 and the first reference point J1 for:

[0088]

[0089] The measuring point c is located in the middle of the slope measuring area. n / 2 The relative displacement change between the first reference point J1 for:

[0090]

[0091] Step three: calculate the displacement transfer error correction values ​​of several measuring points in the vertical direction, and perform vertical correction on several measuring points based on the displacement transfer error correction values ​​of several measuring points in the vertical direction.

[0092] Specifically, during multiple displacement transfer measurements, affected by factors such as measurement point positioning errors and image distortion, displacement transfer will inevitably accumulate errors. The more times the transfer is performed, the greater the accumulated error. To this end, the present invention uses a first reference point J1 and a second reference point J2 to perform a displacement transfer error correction process, and the specific process is as follows:

[0093] From the first reference point J1 and the second reference point J2 to the middle measuring point c of the slope to be measured n / 2 The relative displacement of each measuring point is transmitted and calculated. When it is transmitted to the middle measuring point c of the slope to be measured, n / 2 When the distance from the first reference point J1 to the middle measurement point c is obtained n / 2 Transferred measuring point c n / 2 The first displacement And from the second reference point J2 to the middle measurement point c n / 2 Transferred measuring point c n / 2 The second displacement

[0094] Since the first reference point J1 and the second reference point J2 are both relatively stable points, theoretically the first displacement and the second displacement equal; but due to the displacement transmission error, the first displacement and the second displacement There is a certain transmission cumulative error f between them;

[0095] From the first reference point J1 to the middle measuring point c n / 2 The cumulative error f of transmission is:

[0096]

[0097] The cumulative error f includes the cumulative error of the left or right half of the slope (the left and right half are based on the middle measuring point c n / 2 Theoretically, the more times the transfer is, the greater the cumulative error is. Therefore, the transfer cumulative error f can be distributed according to the ratio of the transfer times of the displacement calculation of the measuring point to the total transfer times, and then the influence of the transfer cumulative error on the displacement calculation can be corrected.

[0098] From the first reference point J1 to the middle measurement point c n / 2 During the transfer, the first measuring point c1 to the intermediate measuring point c n / 2 The error transfer correction number Δ of the displacement of each measuring point between is:

[0099]

[0100] Where m is the number of displacement calculation transfers corresponding to the measurement point, m L From the first measuring point c1 to the middle measuring point c n / 2 The total number of displacement calculation passes.

[0101] Further, Figure 1 Taking the second measuring point c2 in the example, the use of the error transfer correction number Δ of the displacement of each measuring point is specifically described. The second measuring point c2 is located on the left half of the slope, and the number of transfers of the displacement calculation from the first reference point J1 to the second measuring point c2 is 2, then its error transfer correction number is calculated as Δc2;

[0102] The expression of Δc2 is as follows:

[0103]

[0104] Then the corrected displacement of the second measuring point c2 is for:

[0105]

[0106] From the nth measuring point c n To the middle measuring point c n / 2 The calculation is similar to the left side; however, since the calculation starts from the nth measurement point c n To the middle measuring point c n / 2 When the cumulative error f is transmitted, the first displacement is used Subtract the second displacement Therefore, from the nth measurement point c n To the middle measuring point c n / 2 The calculation formula of the error transfer correction number Δ′ is:

[0107]

[0108] Where: m corresponds to the displacement calculation transmission times of the measuring point, m R is the nth measurement point c n To the middle measuring point c n / 2 The total number of displacement calculation passes.

[0109] Step 4: Using the same method as step 2 and step 3, the displacement transfer error correction values ​​of several measuring points in the horizontal direction are respectively calculated, and the several measuring points are respectively corrected in the horizontal direction based on the displacement transfer error correction values ​​of several measuring points in the horizontal direction.

[0110] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A slope displacement monitoring method, characterized in that: The following steps are involved: Step 1: Set up several measuring points, several benchmark points and monitoring equipment in the slope area to be measured; Step 2: Calculate the displacement of several measuring points in the vertical direction based on the reference point, and obtain the relative displacement changes between the several measuring points and the reference point in the vertical direction; Step 3: Calculate the displacement transmission error correction values ​​of several measuring points in the vertical direction, and correct the relative displacement changes of several measuring points in the vertical direction based on the displacement transmission error correction values ​​of several measuring points in the vertical direction; Step 4: Using the same method as steps 2 and 3, the relative displacement changes between several measuring points and the reference point in the horizontal direction are obtained respectively, and the relative displacement changes of several measuring points in the horizontal direction are corrected respectively based on the displacement transfer error correction values ​​of the several measuring points in the horizontal direction.

2. The slope displacement monitoring method according to claim 1, characterized in that: The specific process of setting up several measuring points, several reference points and monitoring equipment is as follows: In the deformation area of ​​the slope to be measured, n measuring points are set in sequence from left to right in an intermittent manner. The n measuring points are counted as (c1,…,c n / 2 ,…,c n ); A first reference point J1 and a second reference point J2 are respectively set on both sides of the deformation area of ​​the slope to be measured; The monitoring equipment is arranged in the middle of the deformation area of ​​the slope to be measured.

3. The slope displacement monitoring method according to claim 2, characterized in that: The specific method for obtaining the relative displacement changes between several measuring points and the reference point in the vertical direction is: S2.

1. Using monitoring equipment, the image coordinates of n measurement points, the first reference point J1, and the second reference point J2 are collected in sequence from left to right to obtain a group E of images; Wherein, E is a natural number greater than or equal to 1; S2.2, respectively calculating the image spacing between each point in the E group of images in the vertical direction to obtain the e group of image spacings; wherein each point includes n measurement points, a first reference point J1 and a second reference point J2; e = (1, 2, ..., E); S2.3, calculating the relative displacement change between each measuring point and the reference point in the second group of images based on the first group of image spacing and the second group of image spacing; Calculate the relative displacement change between each measuring point and the reference point in the third group of images based on the spacing between the first group, the second group, and the third group of images; In this way, the relative displacement changes between each measuring point and the reference point in the E group of images are calculated one by one.

4. The slope displacement monitoring method according to claim 2, characterized in that: Calculate the corrected displacement of the first measuring point c1 in the vertical direction The specific process is as follows: From the first reference point J1 to the middle measuring point c of the slope to be measured n / 2 Transfer and get the measurement point c n / 2 The first displacement From the second reference point J2 to the middle measuring point c of the slope to be measured n / 2 Transfer and get the measurement point c n / 2 The second displacement Let the first displacement and the second displacement The cumulative error between the first reference point J1 and the first measuring point c1 is f, and the number of times the first reference point J1 is transferred to the first measuring point c1 is 1. Then the error transfer correction value Δc1 of the first measuring point c1 is: Where: m L is the middle measuring point c of the slope to be measured from the first reference point J1 n / 2 The total number of transfers made; Then the corrected displacement of the first measuring point c1 in the vertical direction is for:

5. The slope displacement monitoring method according to claim 4, characterized in that: The corrected displacement of the first measuring point c1 in the vertical direction is calculated as follows: The specific process is the same as the steps of the method, and the corrected displacements of other measuring points in the vertical direction and the corrected displacements of the measuring points in the horizontal direction are calculated one by one.

6. The slope displacement monitoring method according to claim 5, characterized in that: From the first reference point J1 to the middle measuring point c n / 2 Transfer or from the second reference point J2 to the intermediate measurement point c n / 2 During the transfer, the first measuring point c1 to the intermediate measuring point c n / 2 Each measurement point between or the nth measurement point c n To the middle measuring point c n / 2 The specific process of the displacement transfer error correction value of each measuring point in the vertical direction is as follows: S3.1, measure from the first reference point J1 to the middle point c n / 2 And from the second reference point J2 to the middle measurement point c n / 2 Transfer, respectively get from the first reference point J1 to the middle measurement point c n / 2 The first displacement transferred And from the second reference point J2 to the middle measurement point c n / 2 The second displacement transmitted S3.2, from the first reference point J1 to the middle measurement point c n / 2 The cumulative error f of transmission is: The cumulative error f is the error from the first reference point J1 to the intermediate measurement point c. n / 2 The cumulative error of transmission; Or, from the second reference point J2 to the middle measuring point c n / 2 The cumulative error of transmission; Then from the first reference point J1 to the middle measurement point c n / 2 During the transfer, the first measuring point c1 to the intermediate measuring point c n / 2 The error transfer correction number Δ of the displacement of each measuring point between is: Where m is the number of displacement calculation transfers corresponding to the measurement point, m L From the first measuring point c1 to the middle measuring point c n / 2 The total number of displacement calculation passes; S3.3, then the error transfer correction Δc1 of the displacement of the first measuring point c1 is: From the first measuring point c1 to the middle measuring point c n / 2 Displacement transmission error correction value setting for: S3.4, repeat step S3.3, and measure from the first measuring point c1 to the middle measuring point c n / 2 The displacement transfer error correction values ​​of the remaining measuring points in the vertical direction are calculated one by one; S3.5, let the nth measurement point c n To the middle measuring point c n / 2 The calculation formula of the error transfer correction number Δ′ is: Among them, m R is the nth measurement point c n To the middle measuring point c n / 2 The total number of displacement calculation passes; Then the nth measurement point c n The error transfer correction factor Δc of the displacement n for: From the nth measuring point c n To the middle measuring point c n / 2 Displacement transmission error correction value setting for: S3.6, repeat step S3.5, for the nth measuring point c n To the middle measuring point c n / 2 The displacement transfer error correction values ​​of the remaining measuring points in the vertical direction are calculated one by one.

Images