An indoor measurement method for the i-angle of a digital level

Abstract

The present invention discloses a method for indoor measurement of the i-angle of a digital level, which is specifically implemented according to the following steps: Step 1, build an indoor measurement system for the i-angle of the digital level; Step 2, observe the virtual image through the digital level and take readings of the leveling staff at a far distance at a near distance indoors; Step 3, after taking readings of the virtual image of the lower leveling staff at a far distance by the digital level in Step 2, that is, after performing indoor far-distance observation and measurement, substitute the measurement data into the i-angle calculation formula to achieve the i-angle measurement of the digital level. The method for indoor measurement of the i-angle of a digital level according to the present invention is simple to operate and has good measurement repeatability, solving the problems of high requirements for existing indoor detection devices for the i-angle of digital levels, inability to aim at and take readings of physical scales at a far distance indoors, and low measurement accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical metrology and relates to a method for indoor measurement of the i-angle of a digital level. Background Art

[0002] The magnitude and stability of the i-angle of a digital level are important conditions for ensuring the accuracy of leveling measurement. At present, the main methods for detecting the i-angle of a digital level are the indoor method and the outdoor method. The outdoor method for measuring the i-angle of a digital level uses the Fielster method. Leveling rods A and B are respectively erected at both ends of a detection baseline with a distance of 45 m, and this baseline is divided into three equal parts. Two instrument stations are set at a distance of 15 m from leveling rods A and B. The instrument observes leveling rods A and B at the two stations respectively, and the observed data is substituted into the electronic i-angle calculation formula to obtain the final result. The indoor method mainly considers that outdoor detection is affected by too many uncontrollable interference factors. To ensure the measurement accuracy, according to the requirements of relevant metrology regulations, in an indoor environment, a collimator group is established as the basic device. When installing, the horizontal parallelism of each collimator should be less than 1", and its target reticle is perpendicular to each other, parallel to the reticle of the level's eyepiece in the vertical direction, and shock protection should be done well to reduce the influence of target shaking on the detection accuracy during the measurement process. Using the target reticle in the collimator (the image of the leveling rod at the corresponding stadia of 15 m and 30 m processed by microreduction technology) as the carrier, a forced centering mounting workbench is used as the mounting table for the digital level, and an overall set of digital level i-angle detection system is formed. According to the requirements of the regulations, a leveled digital level is erected on the mounting table and the microreduction image of the leveling rod at different stadia on the reticle is sighted and read according to the detection procedure to complete the measurement of the electronic i-angle of the digital level.

[0003] The outdoor method is affected by many external factors, which affects the measurement accuracy. For the indoor method, since it is necessary to engrave different coded leveling rods and the microreduction images of the leveling rods at different stadia on the reticle, the applicability of the detection system is not strong. When changing the leveling rod and the stadia, the reticle needs to be replaced and engraved again, which not only increases the manufacturing cost, but also makes the installation and operation very troublesome, and there is also a problem that the detection device cannot be traced. Therefore, both the indoor method and the outdoor method currently have certain defects. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for indoor measurement of the i-angle of a digital level, which is simple to operate and has good measurement repeatability, and solves the problems that the existing indoor detection device for the i-angle of a digital level has high requirements, cannot aim at and read the real object scale at a long distance indoors, and has low measurement accuracy.

[0005] The technical solution adopted by the present invention is a method for indoor measurement of the i-angle of a digital level, which is specifically implemented according to the following steps:

[0006] Step 1, set up the indoor measurement system for the i-angle of the digital level;

[0007] Step 2, observe the virtual image through the digital level and take readings of the virtual image of the level staff at a far distance at a short distance indoors;

[0008] Step 3, after taking readings of the virtual image of the level staff at a far distance in Step 2, that is, after indoor measurement at a far distance, substitute the measurement data into the i-angle calculation formula to realize the i-angle measurement of the digital level.

[0009] The features of the present invention also lie in:

[0010] The indoor measurement system for the i-angle of the digital level in Step 1 includes a placement table, on which a digital level is set. On the same horizontal plane on both sides of the digital level, lens group A and lens group B are respectively set, and level staff A and level staff B are relatively set outside lens group A and lens group B.

[0011] The specific process of Step 2 is to determine that the height difference between level staff A and level staff B is △ H， Adjust lens group A and lens group B so that the digital level observes the virtual image scale A" at a distance of 15 meters from the level staff A through lens group A, and the digital level observes the virtual image scale B" at a distance of 30 meters from the level staff B through lens group B.

[0012] The specific process of adjusting lens group A and lens group B is as follows:

[0013] Both lens group A and lens group B are optical systems with double optical groups. Each combined optical system includes a front optical group and a rear optical group. According to the principle of optical imaging, lens group A and lens group B respectively image the physical level staff at a short distance into a virtual image of a level staff at a far distance at a ratio of 1:1, and use the virtual image of the level staff as the observation object of the digital level.

[0014] Take the real image plane of the front optical group as the object plane of the rear optical group, and at the same time ensure that the real image plane of the front optical group is within the focal length of the rear optical group, so that the physical level staff forms a virtual image through the entire optical group.

[0015] The total magnification of each combined optical system in Step 2 , and the magnification of the rear optical group is denoted as , let the magnification of the front optical group , for the front optical group, there is a relational expression:

[0016] (1);

[0017] In the formula, is the distance from the physical level staff to the object-side principal plane of the front optical group;

[0018] Apply the Gaussian imaging formula to the front optical group , obtain , is the real image distance of the front optical group.

[0019] For the rear optical group, there is a relational expression:

[0020] - (2);

[0021] In the formula, , the sight distance is the sight distance of the virtual image scale to be observed, d 0 is the distance from the image-side principal plane of the rear optical group to the installation center of the digital level;

[0022] For the rear optical group, from the Gaussian imaging formula, there is , where is the distance from the real image formed by the front optical group to the object-side principal plane of the rear optical group.

[0023] After adjusting the lens group A and the lens group B respectively, the imaging magnification of each combined optical system is 1:1, that is, the sizes of the physical level scale and the virtual image level scale are 1:1. Then the virtual images of the level scale A and the level scale B can be observed at the sight distances of 15 meters and 30 meters respectively, which meets the metrological traceability.

[0024] In step 3, observe the line-of-sight height and sight distance of the level scale A and the level scale B, and substitute the installation height difference in step 2 to calculate the i-angle of the digital level to be tested:

[0025] (3);

[0026] In the formula, r A is the line-of-sight height read by the digital level to be tested on the virtual image A" of the level scale, r B is the line-of-sight height read by the digital level to be tested on the virtual image B" of the level scale, d A is the sight distance corresponding to the virtual image A" of the level scale, d B is the sight distance corresponding to the virtual image B" of the level scale, △ H=H A -H B or the height difference corresponding to the virtual images A" and B" of the level scale.

[0027] The beneficial effects of the present invention are as follows: The present invention uses the virtual image formed by the physical level scale through the combined lens as the observation target of the digital level, and applies the Gaussian imaging relationship to adjust the object-image distance of the virtual image formed by the physical level scale with a short sight distance through the combined lens, so as to observe the virtual images of the level scales with different sight distances, realizing aiming and reading of the level scale with a long sight distance at a short sight distance. This makes it more convenient and efficient to detect the i-angle of different digital levels, and the value transfer and traceability chain of the detection system is complete, meeting the requirements of national specifications. Description of the Drawings

[0028] Figure 1 is a schematic layout diagram of an indoor measurement system for the i-angle of a digital level of the present invention;

[0029] Figure 2 is a schematic diagram of a virtual image formed by a leveling staff on one side of an indoor measurement system for the i-angle of a digital level of the present invention through a lens.

[0030] In the figure, 1. Leveling staff A, 2. Leveling staff B, 3. Scale A", 4. Scale B", 5. Lens group A, 6. Digital level, 7. Lens group B, 8. Mounting platform. Detailed Description of the Invention

[0031] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] An indoor measurement method for the i-angle of a digital level of the present invention is specifically implemented according to the following steps:

[0033] Step 1, set up an indoor measurement system for the i-angle of a digital level;

[0034] The indoor measurement system for the i-angle of a digital level in Step 1, as Figure 1 shown, includes a mounting platform 8, on which a digital level 6 is provided. On the same horizontal plane on both sides of the digital level 6, a lens group A 5 and a lens group B 7 are respectively provided. Opposite to the outside of the lens group A 5 and the lens group B 7, a leveling staff A 1 and a leveling staff B 2 are provided.

[0035] Step 2, observe the virtual image through the digital level and read the virtual image of the leveling staff at a far distance at a short distance indoors;

[0036] The specific process of Step 2 is to determine that the height difference between the leveling staff A 1 and the leveling staff B 2 is Δ H， Adjust the lens group A 5 and the lens group B 7 so that the digital level 6 observes the virtual image scale A" 3 at a distance of 15 meters from the leveling staff A 1 through the lens group A 5, and the digital level 6 observes the virtual image scale B" 4 at a distance of 30 meters from the leveling staff B 2 through the lens group B 7.

[0037] The specific process of adjusting the lens group A 5 and the lens group B 7 is as follows:

[0038] Both the lens group A 5 and the lens group B 7 are optical systems composed of double optical groups. Each combined optical system includes a front optical group and a rear optical group. According to the optical imaging principle, the lens group A 5 and the lens group B 7 respectively image the physical leveling staff at a short distance as a virtual image of a leveling staff at a far distance on a 1:1 basis, and use the virtual image of the leveling staff as the observation object of the digital level.

[0039] Take the real image plane of the front optical group as the object plane of the rear optical group, and at the same time ensure that the real image plane of the front optical group is within the focal length of the rear optical group, so that the physical level scale forms a virtual image through the entire optical system; the total magnification of each combined optical system , and the magnification of the rear optical group is denoted as . Let the magnification of the front optical group . For the front optical group, there is a relational expression:

[0040] (1);

[0041] In the formula, is the distance from the physical level scale to the object-side principal plane of the front optical group;

[0042] Apply the Gaussian imaging formula to the front optical group , and obtain , is the real image distance of the front optical group. For the rear optical group, there is a relational expression:

[0043] - (2);

[0044] In the formula, , the sight distance is the sight distance of the virtual image scale to be observed, and d 0 is the distance from the image-side principal plane of the rear optical group to the installation center of the digital level.

[0045] For the rear optical group, from the Gaussian imaging formula, there is , where is the distance from the real image formed by the front optical group to the object-side principal plane of the rear optical group;

[0046] After adjusting the lens group A5 and the lens group B7 respectively, the imaging magnification of each combined optical system is 1:1, that is, the sizes of the physical level scale and the virtual level scale are 1:1, and the virtual images of the level scale A1 and the level scale B2 located at the sight distances of 15 meters and 30 meters can be observed respectively, which meets the requirements of metrological traceability.

[0047] Step 3, after the digital level 6 reads the virtual image of the level scale at a long sight distance in Step 2, that is, after the indoor long sight distance observation and measurement, substitute the measurement data into the i-angle calculation formula to realize the i-angle measurement of the digital level.

[0048] Observe the sight line height and sight distance of the level scale A1 and the level scale B2, and substitute the installation height difference in Step 2 to calculate the i-angle of the digital level to be inspected:

[0049] (3);

[0050] In the formula, r A is the sight line height read by the digital level 6 to be inspected on the virtual image A" of the level scale, and r Bis the line of sight height read by the digital level 6 to be inspected on the virtual image B" of the leveling staff, d A is the stadia distance corresponding to the virtual image A" of the leveling staff, d B is the stadia distance corresponding to the virtual image B" of the leveling staff, △ H=H A -H B or the height difference between the virtual images A" and B" of the corresponding leveling staff.

[0051] When performing the i-angle detection on the leveling staff with different coding rules indoors, only the matching leveling staff needs to be replaced, that is, there is no need to engrave the graduation plates with different codings.

[0052] Embodiment

[0053] In this embodiment, the physical leveling staff is placed indoors at the short sight distances of 2.24 meters and 4.34 meters respectively, and the digital level is used to observe the virtual image leveling staff at 15 meters and 30 meters for the i-angle detection of the digital level.

[0054] In this embodiment, each lens group is an optical system composed of a combination of two optical groups. Each combined optical system is divided into a front optical group and a rear optical group. To meet the field of view requirements, good imaging effect and optimize the whole system, the front optical group is a large field of view short focal length optical group, and the rear optical group is a short distance long focal length optical group. As Figure 2 shown, the real image plane position of each combined optical system is set at the object plane of the rear optical group, and then the real image forms a virtual image through the rear optical group; by changing the measurement stadia distance or the optical group parameters, it can be recalculated through the Gaussian imaging formula. The installation height difference △ H between the leveling staffs A and B in the i-angle calculation formula can be calibrated by using a digital level with an i-angle meeting the measurement safety margin. The △ H in the i-angle calculation formula can be calibrated with the virtual images A" and B" of the leveling staff, which can reduce the manufacturing difficulty of the device and make the installation and adjustment much more convenient.

[0055] When calculating the i-angle, observe the virtual image at a stadia distance of 15 meters for the staff A, observe the virtual image at a stadia distance of 30 meters for the staff B. After calculating the i-angle, then alternate the stadia distances, that is, swap the staff A and the staff B, observe the virtual image at a stadia distance of 30 meters for the staff A, observe the virtual image at a stadia distance of 15 meters for the staff B, calculate the i-angle, and taking the average of the two i-angles can improve the accuracy of the i-angle detection.

[0056] A method for indoor measurement of the i-angle of a digital level in the present invention is simple and easy to implement. According to the principle of optical imaging, a physical level rod at a short sight distance is imaged as a virtual image at a long sight distance through a combination lens, and the digital level observes the virtual image to realize the measurement of the i-angle of the digital level. Through the combination lens, a pair of physical level rods placed at 2.24 meters and 4.34 meters are respectively imaged at a ratio of 1:1 as a pair of virtual level rods with sight distances of 15 meters and 30 meters. Taking a pair of qualified actual level rods as the observation object, for the measurement of the i-angle of digital levels of different brands, only the corresponding brand of level rods needs to be replaced, which solves the problem that the traditional outdoor detection of the i-angle of digital levels requires a large flat site with good environment, moves the outdoor detection indoors, and reduces the influence of outdoor site factors on the measurement accuracy; at the same time, this method also avoids the limitations of other indoor detection methods that require replacing the reticle and cannot be traced, meets the requirements of the metrology system for the traceability of the standard device, and has the characteristics of low cost and high measurement efficiency.

[0057] A method for indoor measurement of the i-angle of a digital level in the present invention is not only applicable to the Fizeau method, but can also be extended to any one of the Least squares method, the Cooke method, and the Japanese method. When necessary, only the optical system needs to be adjusted according to the different sight distance requirements of each measuring station. For the detection of different bar code reticle level rods, only the level rods need to be replaced. At the same time, the digital level can also be replaced by an optical level, and the method for indoor measurement of the i-angle of a digital level described in this article is also applicable to the optical level.

Claims

1. An indoor measurement method for the i-angle of a digital level, characterized in that, it is specifically implemented according to the following steps: Step 1, build an indoor measurement system for the i-angle of a digital level; Step 2, observe the virtual image through the digital level and read the virtual image of the level staff at a far sight distance at a near sight distance indoors; Step 3, after the digital level in Step 2 reads the virtual image of the lower level staff at a far sight distance, that is, after performing indoor far sight distance observation and measurement, substitute the measurement data into the i-angle calculation formula to realize the i-angle measurement of the digital level; The indoor measurement system for the i-angle of the digital level in Step 1 includes a placement table (8), on which a digital level (6) is arranged. On both sides of the digital level (6) at the same horizontal plane, a lens group A (5) and a lens group B (7) are respectively arranged. Opposite to the outside of the lens group A (5) and the lens group B (7), a level staff A (1) and a level staff B (2) are arranged; The specific process of the said step 2 is to determine that the elevation difference between the level staff A (1) and the level staff B (2) is △ H， Adjust the lens group A (5) and the lens group B (7) so that the digital level (6) observes the virtual image scale A" (3) at a stadia of 15 meters of the level staff A (1) through the lens group A (5), and the digital level (6) observes the virtual image scale B" (4) at a stadia of 30 meters of the level staff B (2) through the lens group B (7); The specific process of adjusting the lens group A (5) and the lens group B (7) is as follows: Both the lens group A (5) and the lens group B (7) are optical systems composed of double optical groups. Each combined optical system includes a front optical group and a rear optical group. According to the optical imaging principle, the lens group A (5) and the lens group B (7) respectively image the physical level staff at a near sight distance as a virtual image of a level staff at a far sight distance at a ratio of 1:1, and use the virtual image of the level staff as the observation object of the digital level; Take the real image plane of the front optical group as the object plane of the rear optical group, and at the same time ensure that the real image plane of the front optical group is within the focal length of the rear optical group, so that the physical level staff forms a virtual image through the entire optical group; The total magnification of each combined optical system in step 2 , the magnification of the rear optical group is denoted as , let the magnification of the front optical group , for the front optical group, there is a relational expression: （1）； In the formula, is the distance from the physical level staff to the object-side principal plane of the front optical group; Apply the Gaussian imaging formula to the front optical group , and obtain , is the image distance of the real image of the front optical group. For the rear optical group, there is a relational expression: - （2）； In the formula, , the sight distance is the sight distance of the virtual image scale to be observed, and d 0 is the distance from the image-side principal plane of the rear optical group to the installation center of the digital level; For the rear optical group, according to the Gaussian imaging formula, there is , where is the distance from the real image formed by the front optical group to the object-side principal plane of the rear optical group; After adjusting the lens group A (5) and the lens group B (7) respectively, the imaging magnification of each combined optical system is 1:1, that is, the size ratio of the physical level staff to the virtual level staff is 1:

1. Then the virtual images of the level staff A (1) and the level staff B (2) located at a sight distance of 15 meters and 30 meters can be observed respectively, which meets the requirements of metrological traceability; In Step 3, observe the line of sight height and sight distance of the level staff A (1) and the level staff B (2), and substitute the placement height difference in Step 2 to calculate the i-angle of the digital level to be tested: （3）； Where r A is the line-of-sight height read by the digital level (6) to be tested on the virtual image A" of the leveling staff, and r B is the line-of-sight height read by the digital level (6) to be tested on the virtual image B" of the leveling staff, d A is the stadia distance corresponding to the virtual image A" of the leveling staff, and d B is the stadia distance corresponding to the virtual image B" of the leveling staff, and △ H = H A -H B or the height difference corresponding to the virtual images A" and B" of the leveling staff.

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