Method and system for measuring central axis of steel pipe and electronic equipment

Abstract

The invention belongs to the technical field of mechanical part detection and line laser outline digital detection of parts, particularly relates to a steel pipe central axis measuring method and system and electronic equipment, and aims to solve the problem of low measurement or detection precision caused by noise interference during measurement in the prior art. The method comprises the following steps: extracting data points and fitting a plurality of circles; performing straight line fitting based on the center points of all the fitted circles; calculating the distance from each circle center point to the fitted straight line as an error distance; if at least one error distance greater than the set error distance threshold exists, eliminating the circle center point corresponding to the maximum error distance; judging whether the number of cycles reaches a set number threshold value or error distances corresponding to the remaining circle center points after elimination are all smaller than a set error distance threshold value, and if not, continuing elimination; otherwise, taking the fitted straight line as the central axis of the to-be-measured steel pipe. The influence of image noise on a measurement result is reduced, and the detection precision is improved.

Description

Background Art

[0002] Petroleum energy is an indispensable energy source in the contemporary era. After oil and natural gas are extracted, pipelines are needed to transport oil and natural gas from oil fields to oil and gas processing plants or for long-distance transmission, and the usage of steel pipes is very large. To ensure the reliability of steel pipe butt joints, it is necessary to detect the appearance geometric parameters of the end parts of steel pipes. The pipeline axis is the reference for detecting each parameter, which is of great significance for the processing and detection of the overall dimensions of steel pipes. The industry has put forward higher requirements for the dimensional accuracy of long-distance pipeline steel pipes. Currently, the detection of pipe end parameters is carried out manually.

[0003] When the current line laser profile digital detection method is used, noise interference has a great impact on the measurement results. How to eliminate noise and improve detection accuracy is an urgent problem to be solved. Summary of the Invention

[0004] To solve the above problems in the prior art, that is, in the prior art during measurement, affected by noise interference, especially the noise generated due to the unevenness or deformation of the outer contour, resulting in relatively low measurement or detection accuracy, in the first aspect of the present invention, a method for measuring the central axis of a steel pipe is provided, including:

[0005] Step S1, extracting data points on multiple cross-sections of the outer contour of the steel pipe to be measured and fitting multiple circles; based on the center points of all the fitted circles, performing a straight line fitting to obtain the spatial straight line parameters of the axis of the steel pipe body;

[0006] Step S2, calculating the distance from each center point to the fitted straight line as the error distance; if there is at least one of the error distances greater than the set error distance threshold, then eliminating the center point corresponding to the maximum error distance;

[0007] Step S3, determining whether the number of loops has reached the set loop number threshold or whether the error distances corresponding to the remaining center points after elimination are all less than the set error distance threshold. If not, then based on the remaining center points, performing a straight line fitting and jumping to Step S2; otherwise, ending the loop, performing a straight line fitting based on the remaining center points, and taking the fitted straight line as the central axis of the steel pipe to be measured.

[0008] In some preferred embodiments, when fitting a circle, the data points extracted on each cross-section of the outer contour of the steel pipe to be measured are used to fit one circle.

[0012] In some preferred embodiments, the value range of the error distance threshold is 3 - 5 mm.

[0013] In some preferred embodiments, the number threshold is one-fourth to one-third of the number of center points of all the fitted circles.

[0014] In some preferred embodiments, based on the center points of all the fitted circles, a straight line fitting is performed, and the method is as follows:

[0015] Based on the center points of all the fitted circles, a straight line fitting is performed by the least squares method.

[0016] In some preferred embodiments, for the pipe end chamfering error of the steel pipe to be measured, the measurement method is: taking the axis corresponding to the spatial straight line parameters of the steel pipe body axis as the reference, the pipe end chamfering error is measured.

[0017] In a second aspect of the present invention, a steel pipe central axis measurement system is proposed, and the system includes:

[0018] An extraction fitting module, configured to extract data points on multiple cross-sections of the outer contour of the steel pipe to be measured and fit multiple circles; based on the center points of all the fitted circles, a straight line fitting is performed to obtain the spatial straight line parameters of the steel pipe body axis;

[0019] An error distance judgment module, configured to calculate the distance from each center point to the fitted straight line as the error distance; if there is at least one of the error distances greater than the set error distance threshold, the center point corresponding to the maximum error distance is eliminated;

[0020] A loop judgment module, configured to judge whether the number of loops reaches the set loop number threshold or the error distances corresponding to the remaining center points after elimination are all less than the set error distance threshold. If not, a straight line fitting is performed based on the remaining center points, and the loop judgment module is jumped to; otherwise, the loop ends, a straight line fitting is performed based on the remaining center points, and the fitted straight line is used as the central axis of the steel pipe to be measured.

[0021] In a third aspect of the present invention, an electronic device is proposed, including:

[0022] At least one processor; and a memory communicatively connected to at least one of the processors; wherein, the memory stores instructions executable by the processor, and the instructions are used to be executed by the processor to implement the above-mentioned method for measuring the central axis of a steel pipe.

[0023] In a fourth aspect of the present invention, a computer-readable storage medium is proposed, and the computer-readable storage medium stores computer instructions, and the computer instructions are used to be executed by the computer to implement the above-mentioned method for measuring the central axis of a steel pipe.

[0024] The beneficial effects of the present invention:

[0025] The least squares linear fitting method based on the elimination mechanism of the present invention improves the programming efficiency. When measuring the axis of a steel pipe, it eliminates noise interference and improves the detection accuracy. It solves the problem in the prior art that during the actual measurement of a steel pipe, noise interference is generated due to the unevenness or deformation of the outer contour, thus affecting the axis detection accuracy. In addition, this method is simple and practical in calculation and is convenient for popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Other features, objects, and advantages of the present application will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings:

[0027] Figure 1 is a schematic flow chart of a method for measuring the central axis of a steel pipe according to an embodiment of the present invention;

[0028] Figure 2 is a schematic framework diagram of a system for measuring the central axis of a steel pipe according to an embodiment of the present invention;

[0029] Figure 3 is a schematic diagram of noise point data according to an embodiment of the present invention;

[0030] Figure 4 is a schematic diagram of fitting a straight line by the ordinary least squares method according to an embodiment of the present invention;

[0031] Figure 5 is a schematic diagram of fitting a straight line by the method of the present invention according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following further describes the present application in detail with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related invention and are not intended to limit the invention. Additionally, it should be noted that for the sake of description, only parts related to the relevant invention are shown in the drawings.

[0033] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The following will describe the present application in detail with reference to the drawings and embodiments.

[0034] A method for measuring the central axis of a steel pipe according to the first embodiment of the present invention, as Figure 1 shown, includes:

[0035] Step S1, extracting data points on multiple cross-sections of the outer contour of the steel pipe to be measured and fitting multiple circles; based on the center points of all the fitted circles, performing linear fitting to obtain the spatial linear parameters of the axis of the steel pipe body;

[0036] Step S2, calculate the distance from each center point to the fitted line as the error distance; if there is at least one of the error distances greater than the set error distance threshold, eliminate the center point corresponding to the maximum error distance.

[0037] Step S3, determine whether the number of loops reaches the set loop number threshold or the error distances corresponding to the remaining center points after elimination are all less than the set error distance threshold. If not, based on the remaining center points, perform line fitting and jump to Step S2; otherwise, end the loop, perform line fitting based on the remaining center points, and use the fitted line as the central axis of the steel pipe to be measured.

[0038] To more clearly illustrate the method for measuring the central axis of the steel pipe of the present invention, the following details each step in the method embodiment of the present invention with reference to the drawings.

[0039] Step S1, extract the data points on multiple cross-sections of the outer contour of the steel pipe to be measured and fit multiple circles; based on the center points of all the fitted circles, perform line fitting to obtain the spatial line parameters of the axis of the steel pipe body.

[0040] In this embodiment, for the calculation of the straightness of the steel pipe, first extract the data points on multiple cross-sections of the outer contour of the steel pipe and fit multiple circles to obtain a set of center points; when fitting a circle, one circle is fitted for the data points extracted from each cross-section of the outer contour of the steel pipe to be measured.

[0041] Due to the unevenness or deformation of the outer contour, noise is generated, which affects the measurement accuracy of the axis. The schematic diagram of the noise point data is as Figure 3 shown. To eliminate noise interference and enhance the denoising ability, the present invention provides a method for measuring the central axis of a steel pipe. Preferably, the least squares standard function is used to fit a straight line to the center points of the cross-sections of the outer contour of the steel pipe, that is, based on the center points of all the fitted circles, perform line fitting to obtain the straightness parameter of the steel pipe (the spatial line parameter of the axis of the steel pipe body (i.e., the straight line), and based on this axis, the bevel error at the pipe end can be measured). The schematic diagram of the straight line generally fitted by the least squares method is as Figure 4 shown.

[0042] Step S2, calculate the distance from each center point to the fitted line as the error distance; if there is at least one of the error distances greater than the set error distance threshold, eliminate the center point corresponding to the maximum error distance.

[0043] In this embodiment, calculate the error distance from all points to the straight line, set an error distance threshold K. If the error distance is greater than the threshold K, take the center point corresponding to the maximum error distance and eliminate this point. The value range of the error distance threshold is preferably set to 3 - 5 mm.

[0044] Step S3: Determine whether the number of loops reaches the set loop count threshold or the error distances corresponding to the remaining center points after elimination are all less than the set error distance threshold. If not, perform linear fitting based on the remaining center points and jump to Step S2; otherwise, end the loop, perform linear fitting based on the remaining center points, and use the fitted line as the central axis of the steel pipe to be measured.

[0045] In this embodiment, according to the remaining center points after elimination, the least squares method is used to fit a line, and then the center points are eliminated in the manner of Step S2. A loop count threshold N is set. If the number of loops is less than the threshold N (preferably set to one-fourth to one-third of the number of center points of all fitted circles in the present invention), and at this time the error distances of all points are less than the threshold K, the loop is stopped to obtain the fitted line; or if the number of loops is equal to the threshold N, and at this time there are still points with error distances greater than the threshold K, the loop is stopped to obtain the fitted line, and the fitted line is used as the central axis of the steel pipe to be measured. The schematic diagram of the fitted line is as Figure 5 shown.

[0046] The steel pipe central axis measurement system according to the second embodiment of the present invention is as Figure 2 shown, and the system includes:

[0047] An extraction and fitting module 100, configured to extract data points on multiple cross-sections of the outer contour of the steel pipe to be measured and fit multiple circles; perform linear fitting based on the center points of all the fitted circles to obtain the spatial linear parameters of the central axis of the steel pipe body;

[0048] An error distance judgment module 200, configured to calculate the distance from each center point to the fitted line as the error distance; if there is at least one of the error distances greater than the set error distance threshold, eliminate the center point corresponding to the maximum error distance;

[0049] A loop judgment module 300, configured to judge whether the number of loops reaches the set loop count threshold or the error distances corresponding to the remaining center points after elimination are all less than the set error distance threshold. If not, perform linear fitting based on the remaining center points and jump to the loop judgment module; otherwise, end the loop, perform linear fitting based on the remaining center points, and use the fitted line as the central axis of the steel pipe to be measured.

[0050] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working process and related descriptions of the above-described system can refer to the corresponding process in the foregoing method embodiment, and will not be elaborated herein.

[0051] It should be noted that for the steel pipe central axis measurement system provided in the above embodiments, only the division of the above functional modules is used for illustration. In actual applications, the above functions can be allocated to different functional modules according to needs, that is, the modules or steps in the embodiments of the present invention can be further decomposed or combined. For example, the modules in the above embodiments can be combined into one module, or further split into multiple sub-modules to complete all or part of the functions described above. For the names of the modules and steps involved in the embodiments of the present invention, they are only used to distinguish each module or step and are not regarded as improper limitations of the present invention.

[0052] An electronic device according to a third embodiment of the present invention includes at least one processor; and a memory communicatively connected to at least one of the processors; wherein the memory stores instructions executable by the processor, and the instructions are used to be executed by the processor to implement the above-mentioned steel pipe central axis measurement method.

[0053] A computer-readable storage medium according to a fourth embodiment of the present invention stores computer instructions, and the computer instructions are used to be executed by the computer to implement the above-mentioned steel pipe central axis measurement method.

[0054] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes and related descriptions of the above-mentioned steel pipe central axis measurement device and computer-readable storage medium can refer to the corresponding processes in the foregoing method embodiments and will not be repeated here.

[0055] Those skilled in the art should be able to realize that the modules and method steps of each example described in combination with the embodiments disclosed in this article can be implemented by a combination of electronic hardware, computer software, or both. The programs corresponding to the software modules and method steps can be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well-known in the technical field. To clearly illustrate the interchangeability of electronic hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in the form of electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0056] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus / device.

[0057] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easily understood by those skilled in the art that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

Claims

1. A method for measuring the central axis of a steel pipe, characterized in that, The method includes the following steps: Step S1: Extract data points on multiple cross-sections of the outer contour of the steel pipe to be measured and fit multiple circles; based on the center points of all the fitted circles, perform a linear fit to obtain the spatial linear parameters of the axis of the steel pipe body; Step S2: Calculate the distance from each center point to the fitted line as the error distance; if there is at least one of the error distances greater than the set error distance threshold, then eliminate the center point corresponding to the maximum error distance; Step S3: Determine whether the number of loops has reached the set loop number threshold or whether the error distances corresponding to the remaining center points after elimination are all less than the set error distance threshold. If not, then perform a linear fit based on the remaining center points and jump to Step S2; otherwise, end the loop, perform a linear fit based on the remaining center points, and use the fitted line as the central axis of the steel pipe to be measured.

2. The method for measuring the central axis of a steel pipe according to claim 1, characterized in that When fitting a circle, fit one circle with the data points extracted from each cross-section of the outer contour of the steel pipe to be measured.

3. A method for measuring the central axis of a steel pipe according to claim 2, characterized in that The value range of the error distance threshold is 3 - 5 mm.

4. A method for measuring the central axis of a steel pipe according to claim 3, characterized in that, The number threshold is one-fourth to one-third of the number of center points of all the fitted circles.

5. A method for measuring the central axis of a steel pipe according to claim 4, characterized in that, Based on the center points of all the fitted circles, perform a linear fit, and the method is as follows: Based on the center points of all the fitted circles, perform a linear fit by the least squares method.

6. A method for measuring the central axis of a steel pipe according to claim 5, characterized in that, For the pipe end chamfering error of the steel pipe to be measured, the measurement method is: taking the axis corresponding to the spatial linear parameters of the axis of the steel pipe body as the reference, measure the pipe end chamfering error.

7. A steel pipe central axis measurement system, characterized in that, The system includes: An extraction and fitting module configured to extract data points on multiple cross-sections of the outer contour of the steel pipe to be measured and fit multiple circles; based on the center points of all the fitted circles, perform a linear fit to obtain the spatial linear parameters of the axis of the steel pipe body; An error distance judgment module configured to calculate the distance from each center point to the fitted line as the error distance; if there is at least one of the error distances greater than the set error distance threshold, then eliminate the center point corresponding to the maximum error distance; A loop judgment module configured to determine whether the number of loops has reached the set loop number threshold or whether the error distances corresponding to the remaining center points after elimination are all less than the set error distance threshold. If not, then perform a linear fit based on the remaining center points and jump to the loop judgment module; otherwise, end the loop, perform a linear fit based on the remaining center points, and use the fitted line as the central axis of the steel pipe to be measured.

8. An electronic device, characterized in that, It includes: At least one processor; And a memory communicatively connected to at least one of the processors; Wherein, the memory stores instructions executable by the processor, and the instructions are used to be executed by the processor to implement a method for measuring the central axis of a steel pipe according to any one of claims 1 - 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions, and the computer instructions are used to be executed by the computer to implement a method for measuring the central axis of a steel pipe according to any one of claims 1 - 6.

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