Steel ruler distance measuring method

Abstract

The invention discloses a steel ruler distance measurement method, which utilizes high-precision operation of software and high-pixel characteristics of pictures to obtain decimal-digit accurate readings of measured values of a steel ruler, so that the distance measurement precision of the steel ruler is maximally improved to a submillimeter level (namely, the precision reaches 0.1 mm), and the limitation that the minimum scale of a common steel ruler is 1mm and the readings smaller than 1mm can only be estimated and read is broken through. High-precision distance measurement based on a common steel ruler is achieved, and the high-precision distance measurement requirement in the industry needing to adopt the steel ruler for distance measurement at present can be met. Besides, by setting the standard ruler and acquiring the conversion coefficient k for converting the measured value of the to-be-used steel ruler into the measured value of the standard ruler, the length of the standard ruler can be compared, correction of the length of the steel ruler is achieved, the reliability and accuracy of steel ruler measurement are ensured, and the method is particularly suitable for the situation that the steel ruler is long. And the problem that the length of the steel ruler is changed due to temperature change or different tensile forces, so that the inaccuracy of a measurement result is increased is effectively avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of distance measurement, and relates to a method for precise distance measurement, and in particular to a method for measuring distance with a steel ruler using images to assist in high-precision distance measurement. Background Art

[0002] Distance measurement is indispensable in the construction of railways, highways, bridges, tunnels, dams, residential buildings, etc. At present, distance measurement technology has developed very maturely. Micrometers can be used to measure small distances, electromagnetic waves are usually used to measure longer distances, and satellite positioning technology can be used to measure distances from 10km to 1000km.

[0003] In some applications, steel rulers are still used to measure distance. For example, in GNSS control measurement, a small steel ruler is needed to measure the vertical distance from the phase center of the GNSS receiver to the ground point. Under normal circumstances, the accuracy requirement for the geodetic height of the control point is not high, so it is sufficient to measure to the millimeter. However, in some high-precision positioning, there are also very high requirements for the GNSS geodetic height. Obviously, ordinary small steel rulers are difficult to meet the measurement requirements. In addition, in bridge construction, it is often necessary to transfer the elevation point under the bridge to the bridge deck. Due to the particularity of the measurement method, an electromagnetic wave rangefinder cannot be used, and only a steel ruler can be used; however, the minimum scale of the steel ruler is 1mm, and readings less than 1mm can only be estimated, and the accuracy is difficult to meet the application requirements. And in the case of a long steel ruler, the length of the steel ruler will change due to temperature changes or different tensions, further increasing the inaccuracy of the measurement results.

[0004] To sum up, in some occasions in the industry where steel ruler distance measurement is required, such as the above-mentioned GNSS geodetic height measurement case and the elevation point measurement case under the bridge where a steel ruler must be used for distance measurement, the steel ruler is often unable to meet the high-precision measurement requirements due to the accuracy limitation of the minimum scale value and the limitation of the usage scenario. Based on this, the present invention proposes a high-precision measurement method based on steel ruler distance measurement to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a novel steel ruler distance measurement method, which utilizes image-assisted measurement to achieve high-precision distance measurement of an ordinary steel ruler, so as to solve the problem that in industries currently requiring steel ruler distance measurement, the steel ruler measurement accuracy is low and cannot meet the high-precision distance measurement requirements.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a distance measuring method with a steel ruler, comprising the steps of:

[0008] S1, measuring the ruler length CC' corresponding to the Amm measurement interval on the standby steel ruler, measuring the ruler length DD' corresponding to the Amm measurement interval on the standard ruler, and obtaining a conversion coefficient k=DD' / CC' from the measured value of the standby steel ruler to the measured value of the standard ruler;

[0009] S2, using the standby steel ruler to measure the distance, obtaining the reading part picture at the measurement integer position and the measurement decimal position x corresponding to the reading indicator line on the standby steel ruler; importing the reading part picture into the image processing software, using the distance measurement function of the image processing software, and measuring the distance between the reading part and the image. AB and D OB The value of D AB is the parallel distance between the first scale line and the second scale line in the unit mm where the reading indicator line is located in the reading part picture. The first scale line is located outside the range to be measured and corresponds to the next unit mm scale of the measurement integer. The second scale line is located within the range to be measured and corresponds to the measurement integer. OB is the parallel distance between the reading indicator line and the second scale line in the reading part picture; then use the formula:

[0010]

[0011] The measurement decimal places corresponding to the reading indicator line are calculated:

[0012]

[0013] Then the measured integer digit is added to the measured decimal digit x to obtain the actual measured value of the steel ruler to be used;

[0014] S3. Multiply the actual measured value by the conversion coefficient k in step S1 to correct the actual measured value and obtain a final measured value.

[0015] In some implementations, step S1 comprises the steps of:

[0016] S11, placing the standby steel ruler and the standard ruler side by side, and acquiring a double-rule image;

[0017] S12, importing the dual ruler image into the image processing software, and using the distance measurement function of the image processing software to measure the ruler length CC' and the ruler length DD';

[0018] S13, obtaining a conversion coefficient k=DD` / CC` for converting the measured value of the standby steel ruler to the measured value of the standard ruler.

[0019] In some implementations, the dual-scale image is acquired by photographing with a camera.

[0020] In some embodiments, the reading site image is acquired by taking pictures with a camera.

[0021] In some implementations, the image processing software is a CAD editor.

[0022] In some implementations, in step S12, after the dual ruler image is imported into the image processing software, it is first amplified, and then the ruler length CC' and the ruler length DD' are measured using the distance measurement function of the image processing software.

[0023] In some embodiments, in step S12, after the dual ruler image is enlarged, the central axes are first drawn on the scale lines at both ends of the stand-by steel ruler and the standard ruler corresponding to the Amm measurement interval, and then the distance measurement function of the image processing software is used to measure the central axis distance of the scale lines at both ends of the Amm measurement interval to obtain the ruler length CC` and the ruler length DD`.

[0024] In some embodiments, in step S2, after the reading part picture is imported into the image processing software, it is first amplified, and then the distance measurement function of the image processing software is used to measure the D in the reading part picture. AB and D OB The numerical value of .

[0025] In some embodiments, in step S2, after the reading part image is enlarged, the central axis is first drawn on the reading index line, the first scale line and the second scale line, and then the distance between the central axes of the first scale line and the second scale line is measured using the distance measurement function of the image processing software as D AB , and measure the distance between the central axis of the reading indicator line and the second scale line as D OB .

[0026] In some implementations, in step S1, the Amm measurement interval is 10 mm.

[0027] Compared with the prior art, the present invention has achieved the following technical effects:

[0028] The steel ruler distance measurement method provided by the present invention utilizes image-assisted high-precision and precise distance measurement. It utilizes the high-precision operation of the software and the high-pixel characteristics of the image to obtain accurate decimal readings of the steel ruler measurement value, so that the steel ruler distance measurement accuracy is improved to the sub-millimeter level (that is, the accuracy reaches 0.1mm), breaking the limitation that the minimum scale of an ordinary steel ruler is 1mm and readings less than 1mm can only be estimated, and realizing high-precision distance measurement based on an ordinary steel ruler, which can meet the high-precision distance measurement needs in the current industry that needs to use steel ruler distance measurement.

[0029] In addition, the present invention sets a standard ruler and obtains a conversion coefficient k for converting the measured value of the stand-by steel ruler to the measured value of the standard ruler, thereby comparing the length of the standard ruler and correcting the length of the steel ruler to ensure the reliability and accuracy of the steel ruler measurement. This is especially suitable for situations where the steel ruler is relatively long, and effectively avoids the problem of the steel ruler length changing due to temperature changes or different tensions, thereby increasing the inaccuracy of the measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A schematic diagram of the principle of obtaining the conversion coefficient k in one or more embodiments;

[0032] Figure 2 A schematic diagram of the acquisition principle of measuring a decimal place x in one or more embodiments;

[0033] Figure 3 for Figure 2 Schematic diagram of the enlarged structure at F in the middle.

[0034] In the figure, the reference numerals are:

[0035] 1. Steel ruler for use;

[0036] 2. Standard ruler;

[0037] 3. Reading indicator line;

[0038] 4. The first scale line;

[0039] 5. Second scale line;

[0040] 6. Central axis. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The purpose of the present invention is to provide a novel steel ruler distance measurement method, which utilizes image-assisted measurement to achieve high-precision distance measurement of an ordinary steel ruler, so as to solve the problem that in industries currently requiring steel ruler distance measurement, the steel ruler measurement accuracy is low and cannot meet the high-precision distance measurement requirements.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] like Figure 1 to Figure 3 As shown, this embodiment provides a distance measuring method with a steel ruler, comprising the steps of:

[0045] S1, measure the ruler length CC' corresponding to the measurement interval of Amm on the standby ruler 1, measure the ruler length DD' corresponding to the measurement interval of Amm on the standard ruler 2, and obtain the conversion coefficient k=DD' / CC' from the measurement value of the standby ruler 1 to the measurement value of the standard ruler 2; the above A is generally a positive integer greater than zero, such as Figure 1 As shown, the Amm measurement intervals on the standby steel ruler 1 and the standard ruler 2 are both 122-123, that is, A is 10. The standard ruler 2 is set as the benchmark for the length change of the standby steel ruler 1 caused by any possible external factors, and the actual measurement value of the standby steel ruler 1 can be corrected to the real measurement data with higher accuracy. The standard ruler 2 can use the same specifications as the standby steel ruler 1, or can use a measuring ruler type different from the steel ruler, such as a meter ruler. Compared with the standby steel ruler 1, the main condition for the standard ruler 2 to be used as a benchmark is that the standard ruler 2 will not deform or the deformation can be ignored. Generally, the standard ruler 2 can use an indium tile ruler or a wooden measurement ruler, and its length will not or basically will not change, thereby maintaining the accuracy of the scale value on the standard ruler 2. In practical applications, the above A can also use values ​​other than 10mm, such as 8mm, 9mm, 12mm or 18mm, etc. It is sufficient to ensure that the scale interval corresponding to the length CC' measured on the standby steel ruler 1 is exactly the same as that of the standard ruler 2.

[0046] S2, using the standby steel ruler 1 to measure the distance, and obtaining the distance reading indicator line 3 (i.e. Figure 3 The nearest measurement integer position (millimeter level) of the line O`O`` shown in the figure, and at the same time obtain the reading position picture at the measurement decimal position x corresponding to the reading indicator line 3, such as Figure 2 The distance measurement interface of the steel ruler 1 is shown. At this time, the reading indicator line 3 is located in the unit mm interval above the measurement integer position. The obtained reading part picture is imported into the image processing software. The high-pixel display and high-precision distance measurement function of the image processing software are used to measure the D in the reading part picture. AB and D OB The value of Figure 3 As shown, D ABD is the parallel distance between the first scale line 4 and the second scale line 5 in mm where the reading indicator line 3 is located in the reading part picture, that is, the parallel distance value from point A to point B, AB Corresponding to the unit length mm (i.e. 1 mm) in the real steel ruler 1 to be used, the first scale line 4 and the second scale line 5 are the two scale lines closest to the reading indicator line 3, wherein the first scale line 4 (i.e. Figure 3 The parallel line above the line O`O`` shown in the figure is located outside the range to be measured and corresponds to the next unit mm scale of the integer position of the measurement. The second scale line 5 (i.e. Figure 3 The parallel line below the line O`O`` shown in FIG. 1 is located within the range to be measured. In fact, the second scale line 5 corresponds to the aforementioned integer position of the measurement. OB is the parallel distance between the reading indicator line 3 and the second scale line 5 in the reading part picture, that is, the parallel distance value from point O to point B; then according to the certain proportional difference between the real steel ruler 1 to be used and the picture, the D in the reading part picture can be determined by using the principle of equal proportion. OB / D AB The ratio of is the same as the value x corresponding to the reading index line 3 in the unit mm in the real steel ruler 1 to be used, and the ratio of 1mm is thus established:

[0047]

[0048] Then the above formula can be used to calculate the measurement decimal place corresponding to the reading indicator line 3:

[0049]

[0050] Then add the measured integer digit directly read above to the measured decimal digit x calculated above to obtain the actual measured value of the steel ruler 1 to be used. OB / D AB The value of is obtained with high precision using image processing software. Based on this, the x value at the 0.1mm level can be obtained and the accuracy of the x value can be ensured.

[0051] S3. Multiply the actual measurement value obtained in step S2 by the conversion coefficient k in step S1 to correct the actual measurement value and obtain a high-precision final measurement value.

[0052] In some implementations, the aforementioned step S1 specifically includes the following steps:

[0053] S11, such as Figure 1 As shown, the steel ruler 1 to be used and the standard ruler 2 are placed side by side, and a camera is used to capture the dual ruler images. Figure 1In the figure, there is an obvious difference in the length of the interval 122-123 between the stand-by steel ruler 1 and the standard ruler 2. This difference is only for illustration and is to enable those skilled in the art to clearly understand the measurement principle of this scheme. In actual applications, the difference in the length of the stand-by steel ruler 1 and the standard ruler 2 corresponding to the same scale interval is extremely subtle and cannot even be observed with the naked eye.

[0054] S12, importing the dual ruler images into the image processing software, and using the high-pixel display and high-precision distance measurement function of the image processing software to measure the ruler length CC' and the ruler length DD';

[0055] S13, obtaining a conversion coefficient k=DD` / CC` for converting the measured value of the standby steel ruler 1 to the measured value of the standard ruler 2.

[0056] In some implementations, the dual-scale images are preferably acquired by photographing with a camera, such as a high-pixel CCD camera or other digital camera.

[0057] In some embodiments, the above-mentioned reading part picture is preferably obtained by taking pictures with a camera, such as a digital camera such as a high-pixel CCD camera.

[0058] In some implementations, the image processing software may be a CAD editor or other CAD drawing software. The CAD editor and related CAD drawing software are conventional software, and the specific distance measurement principle is not described in detail here.

[0059] In some embodiments, in the above step S12, after the dual-rule image is imported into the image processing software, it is generally enlarged first, and then the distance measurement function of the image processing software is used to measure the ruler length CC' and ruler length DD'. Taking the image processing software as a CAD editor as an example, in actual operation, after the dual-rule image is imported into the CAD editor and enlarged, the scale lines at both ends of the corresponding Amm measurement interval of the stand-by steel ruler 1 and the standard ruler 2 will become thicker and become rectangular bars. In order to improve the distance measurement accuracy, it is preferred that after the dual-rule image is enlarged, the center axis 6 is first drawn at the center of the scale lines at both ends of the corresponding Amm measurement interval of the stand-by steel ruler 1 and the standard ruler 2, and then the distance measurement function of the CAD editor is used to measure the distance between the center axis 6 of the scale lines at both ends of the Amm measurement interval, thereby obtaining the ruler length CC' and ruler length DD'.

[0060] Similarly, in some embodiments, in step S2, after the reading part picture is imported into the image processing software, it is generally first amplified, and then the distance measurement function of the image processing software is used to measure the D in the reading part picture. AB and D OB Taking the image processing software as a CAD editor as an example, in actual operation, Figure 3As shown, after the reading part picture is imported into the CAD editor and enlarged, the reading index line 3, the first scale line 4 and the second scale line 5 will become thicker and become rectangular bars. In order to improve the distance measurement accuracy, it is preferred that after the reading part picture is enlarged, the central axis 6 is first drawn at the center of the reading index line 3, the first scale line 4 and the second scale line 5, and then the distance measurement function of the CAD editor is used to measure the distance between the central axes of the first scale line 4 and the second scale line 5 as D AB , and measure the distance between the center axis of the reading index line 3 and the second scale line 5 as D OB .

[0061] In the above steps S2 and S12, the image magnification function is a conventional function of the CAD editor, and the details are not repeated here. At the same time, the drawing of the center axis 6 is also based on the conventional straight line drawing function of the CAD editor, combined with the center reference alignment function of the CAD editor, which can ensure that the drawn center axis 6 is indeed located at the center position of the corresponding long thick line.

[0062] As can be seen from the above, the distance measurement method provided by the steel ruler in this embodiment mainly includes three key links, namely: reading the integer digit of the measurement, measuring and converting the readings that are less than the integer digit, merging the reading results and correcting the ruler length. Among them, the measurement and conversion of the readings that are less than the integer digit is the most critical. Figure 2 and Figure 3 The distance measurement interface of the steel ruler is shown in the figure. In the figure, O`O`` is the reading indicator line 3. As long as the actual parallel distance between points BO can be accurately obtained, the accurate distance measurement of the steel ruler can be ensured. In actual operation, the distance measurement function of the image processing software is used to measure the distance between AB and OB in the software window interface. The measured values ​​are set to be D AB , D OB ; Assume that the length of the standby ruler 1 corresponding to OB is x, and because the length of the standby ruler 1 corresponding to AB is 1 mm, then the formula

[0063] Established, it can be obtained that:

[0064] Finally, add the integer scale value corresponding to point B on the surface of the steel ruler 1 to be used to x, and the actual measurement result of the steel ruler 1 to be used is obtained.

[0065] Generally, when the distance to be measured is long, it is necessary to perform a ruler length correction on the actual measurement result, that is, multiply the actual measurement result by the conversion coefficient k to obtain the final measurement result.

[0066] Since the distance measurement accuracy of image processing software such as CAD editors can reach the pixel level, practice shows that the distance measurement accuracy using this method can reach 0.1mm or higher.

[0067] As can be seen from the above, the steel ruler distance measurement method provided by this scheme uses image assistance to perform high-precision and precise distance measurement, and uses the magnification and pixel measurement functions of digital photos or pictures to increase the accuracy of steel ruler distance measurement to the sub-millimeter level (that is, the accuracy reaches 0.1mm), breaking the limitation that the minimum scale of ordinary steel ruler is 1mm and readings less than 1mm can only be estimated, and realizing high-precision distance measurement based on ordinary steel ruler, which can meet the high-precision distance measurement needs of the current industry that needs to use steel ruler distance measurement. In addition, this scheme sets a standard ruler and obtains the conversion coefficient k=DD` / CC` from the measurement value of the standby steel ruler to the measurement value of the standard ruler. It can compare the length of the standard ruler and realize the correction of the length of the steel ruler to ensure the reliability and accuracy of the steel ruler measurement. It is suitable for the case where the steel ruler is long, and effectively avoids the problem that the length of the steel ruler changes due to temperature changes or different tensions, thereby increasing the inaccuracy of the measurement results.

[0068] The steel ruler distance measurement method provided by this solution is novel and ingenious in conception, does not increase costs, and is simple and easy to operate, and can meet all current applications involving high-precision distance measurement with steel rulers.

[0069] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A distance measuring method using a steel ruler, characterized in that: Includes steps: S1, measuring the ruler length CC' corresponding to the Amm measurement interval on the standby steel ruler, measuring the ruler length DD' corresponding to the Amm measurement interval on the standard ruler, and obtaining a conversion coefficient k=DD' / CC' from the measured value of the standby steel ruler to the measured value of the standard ruler; S2, using the standby steel ruler to measure the distance, obtaining the reading part picture at the measurement integer position and the measurement decimal position x corresponding to the reading indicator line on the standby steel ruler; importing the reading part picture into the image processing software, using the distance measurement function of the image processing software, and measuring the distance between the reading part and the image. AB and D OB The value of D AB is the parallel distance between the first scale line and the second scale line in the unit mm where the reading indicator line is located in the reading part picture. The first scale line is located outside the range to be measured and corresponds to the next unit mm scale of the measurement integer. The second scale line is located within the range to be measured and corresponds to the measurement integer. OB is the parallel distance between the reading indicator line and the second scale line in the reading part picture; then use the formula: The measurement decimal places corresponding to the reading indicator line are calculated: Then the measured integer digit is added to the measured decimal digit x to obtain the actual measured value of the steel ruler to be used; S3. Multiply the actual measured value by the conversion coefficient k in step S1 to correct the actual measured value and obtain a final measured value.

2. The distance measuring method with a steel ruler according to claim 1, characterized in that: Step S1 includes the steps of: S11, placing the standby steel ruler and the standard ruler side by side, and acquiring a double-rule image; S12, importing the dual ruler image into the image processing software, and using the distance measurement function of the image processing software to measure the ruler length CC' and the ruler length DD'; S13, obtaining a conversion coefficient k=DD` / CC` for converting the measured value of the standby steel ruler to the measured value of the standard ruler.

3. The distance measuring method with a steel ruler according to claim 2, characterized in that: The double-scale image is acquired by photographing with a camera.

4. The distance measuring method with a steel ruler according to claim 1, characterized in that: The reading part picture is obtained by taking pictures with a camera.

5. The distance measuring method with a steel ruler according to any one of claims 2 to 4, characterized in that: The image processing software is a CAD editor.

6. The distance measuring method with a steel ruler according to claim 5, characterized in that: In step S12, after the dual ruler image is imported into the image processing software, it is first enlarged, and then the ruler length CC' and the ruler length DD' are measured using the distance measurement function of the image processing software.

7. The distance measuring method with a steel ruler according to claim 6, characterized in that: In step S12, after the dual ruler image is enlarged, the central axis is first drawn on the scale lines at both ends of the standby steel ruler and the standard ruler corresponding to the Amm measurement interval, and then the distance between the central axis lines of the scale lines at both ends of the Amm measurement interval is measured using the distance measurement function of the image processing software to obtain the ruler length CC' and the ruler length DD'.

8. The distance measuring method with a steel ruler according to claim 5, characterized in that: In step S2, after the reading part picture is imported into the image processing software, it is first amplified, and then the distance measurement function of the image processing software is used to measure the D in the reading part picture. AB and D OB The numerical value of .

9. The distance measuring method with a steel ruler according to claim 8, characterized in that: In step S2, after the reading part image is enlarged, the central axis is first drawn on the reading index line, the first scale line and the second scale line, and then the distance between the central axes of the first scale line and the second scale line is measured by using the distance measurement function of the image processing software as D AB , and measure the distance between the central axis of the reading indicator line and the second scale line as D OB .

10. The distance measuring method with a steel ruler according to any one of claims 1 to 4, characterized in that: In step S1, the Amm measurement interval is 10 mm.

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