CN113188440A - Flexible marker and resistance strain gauge space coordinate non-contact type positioning method - Google Patents
Flexible marker and resistance strain gauge space coordinate non-contact type positioning method Download PDFInfo
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- CN113188440A CN113188440A CN202110403570.5A CN202110403570A CN113188440A CN 113188440 A CN113188440 A CN 113188440A CN 202110403570 A CN202110403570 A CN 202110403570A CN 113188440 A CN113188440 A CN 113188440A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/002—Measuring arrangements characterised by the use of optical techniques for measuring two or more coordinates
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
- G01B7/18—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge using change in resistance
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- Length Measuring Devices By Optical Means (AREA)
Abstract
The invention provides a flexible marker and a non-contact positioning method for a space coordinate of a resistance strain gauge, belonging to the technical field of measurement and testing. The invention provides a space coordinate non-contact type positioning method of a resistance strain gauge, which comprises a test piece, the strain gauge and a camera, wherein the flexible marker is arranged on one side of the strain gauge, which is far away from the test piece, and comprises the following steps: carrying out scheme design and measurement preparation; designing a flexible marker according to the strain gauge; sticking a strain gauge and a flexible marker; utilizing a camera to shoot digital images; carrying out data processing; therefore, the space coordinate non-contact type positioning of the large-scale structure test resistance strain gauge is completed. Compared with the prior art, the method has the advantages of convenient identification, unique serial number, accurate positioning and identification, automatic follow-up solving and conversion processes, and solves the problems in the prior art.
Description
Technical Field
The invention belongs to the technical field of measurement and testing, and particularly relates to a flexible marker and a space coordinate non-contact type positioning method of a resistance strain gauge.
Background
With the continuous deepening of human exploration space, countries in the world have aimed more and more exploration targets at farther deep space, and the capacity of further improving space access becomes a common choice for all countries. In order to consolidate the dominant position of the carrier rocket in China in the world aerospace world and shorten the gap between the carrier rocket and the leading country, China is accelerating the research work of developing large carrier rockets.
In order to ensure that the carrier rocket has larger carrying capacity and the missile has longer range, the diameters of the missile and rocket body structure mainly based on the barrel shell structure are inevitably increased, and the large-diameter rocket body test technology is promoted to be one of several important key technologies of large carrier rockets. Similarly, the loading test of the large-diameter cartridge shell structure also faces a number of difficulties. In order to make the measurement data in the ground test more accurate, the space coordinates of the resistance strain gauge need to be acquired, and the main difficult problems are the following aspects:
firstly, a test piece is generally of a spatial structure, and the coordinates of the strain gauge are difficult to obtain by the traditional measurement method of manual work and a ruler;
compared with the large structure size, the strain gauge is small in size, and great challenges are brought to identification and positioning;
and thirdly, solving and converting the space coordinate after identification.
The above conditions lead to increased difficulty in implementing space coordinate positioning of the strain gauge and complicated measurement.
The space positioning of the large-scale structure test resistance strain gauge has important significance for improving the accuracy of test data. In the conventional test, the spatial position measurement of the resistance strain gauge cannot meet the test requirements due to a plurality of difficulties.
In summary, in the prior art, when the spatial position of the resistance strain gauge for the large-scale structural test is measured, the manual method is low in measurement efficiency and difficult to operate, and the traditional image recognition method for directly recognizing the resistance strain gauge is limited by the large size difference between the strain gauge and the structural part, so that the problems of inaccurate positioning and recognition, difficult subsequent solution and difficult conversion exist, and improvement is needed.
Disclosure of Invention
The invention provides a non-contact positioning method for space coordinates of a flexible marker and a resistance strain gauge, and aims to solve the problems of inaccurate positioning and identification, difficult subsequent solution and conversion, low measurement efficiency and difficult operation in the prior art.
The purpose of the invention is realized by the following technical scheme:
a flexible marker is provided, a plurality of coding points are designed on the flexible marker, and the flexible marker has rotation, translation and scale invariance.
As a further optimization, the coding points of the flexible marker are concentric circular ring type coding points which comprise three concentric circular rings, namely an inner circular ring, a first outer circular ring and a second outer circular ring. The inner ring is a solid circular part, the first outer ring is a spacer ring, and the second outer ring is an encoding band.
The flexible marker is further optimized by adopting a binary coding principle, a coding band is equally divided into n equal parts, each equal part represents a binary digit, the black is 0, the white is 1, n binary digits are formed in the clockwise direction, the binary digits correspond to decimal numbers, the minimum decimal value is selected as the coding value of the coding mark point, and the coding value is uniquely determined.
As a further optimization, the flexible marker is also provided with a decimal number corresponding to the code of the code point.
As a further optimization, the flexible marker equally divides the encoded band into fifteen equal parts.
The invention also provides a non-contact positioning method for the space coordinate of the resistance strain gauge, which comprises a test piece, the strain gauge and a camera, wherein any one of the flexible markers is adopted, and the flexible marker is arranged on one side of the strain gauge, which is far away from the test piece, and the method comprises the following steps:
firstly, carrying out scheme design and measurement preparation;
secondly, designing a flexible marker according to the strain gauge;
thirdly, sticking a strain gauge and a flexible marker;
fourthly, shooting a digital image by using a camera;
fifthly, processing data;
therefore, the space coordinate non-contact type positioning of the large-scale structure test resistance strain gauge is completed.
As a further optimization, when the strain gauge and the flexible marker are adhered in the third step, the designed flexible marker is manufactured on a paper-based material and then adhered on the surface of the strain gauge, the strain gauge is provided with a centering base line and is adhered after being centered with a scribed line on the surface of a test piece during adhering, and the centering base lines are also manufactured at the centers of four sides of the flexible marker, namely after the three base lines are centered, the flexible marker is adhered on the surface of the strain gauge.
As further optimization, the digital image shooting in the fourth step is carried out in a local shooting and integral resolving mode, the integral measurement scheme is that the structure is uniformly shot and measured, key parts are shot in a key mode, and a non-collinear point is additionally added in the two measurements.
As a further optimization, when data processing is performed in the fifth step, the identification process includes image preprocessing, whole pixel edge extraction, marker point feature screening, center sub-pixel positioning, and encoding point decoding, the image preprocessing obtains the edge of an image based on a Canny operator, screening is performed according to the inherent features of the marker points, including a boundary closing criterion, a size criterion, a roundness criterion, and a position criterion, and when the geometric shape of the image formed by the circular marker on the target surface of the camera is an ellipse, the correlation coefficient of the ellipse equation is obtained based on a least square fitting mode.
As further optimization, the flexible marker is also provided with a decimal number corresponding to the code of the coding point, and the decimal number corresponding to the code of the coding point in the flexible marker is consistent with the number of the strain gauge in a test system.
The beneficial technical effects obtained by the invention are as follows:
compared with the prior art, the technical scheme provided by the invention is that a flexible marker capable of being used for image recognition is designed and manufactured, the flexible marker is adhered to the surface of the resistance strain gauge, the image coordinates of the flexible marker are obtained through an image processing technology, and the space coordinates of the strain gauge are calculated through three-dimensional reconstruction and the like. The novel space positioning method for the resistance strain gauge in the large-scale structure test is realized, and the measurement and acquisition of the space coordinates of the resistance strain gauge in the general large-scale structure test can be met.
The method is stable and reliable, when the space position of the large-scale structural test resistance strain gauge is measured, the measurement efficiency is greatly improved compared with that of a manual method, compared with the method of directly identifying the resistance strain gauge by adopting a traditional image identification method, the method is convenient to identify, unique in serial number, accurate in positioning and identification, automatic in subsequent solving and converting processes, accurate and reliable in result, solves the problems in the prior art, and has outstanding substantive characteristics and remarkable progress.
Drawings
FIG. 1 is a schematic view of the distribution of encoding points of one embodiment of the flexible marker of the present invention;
FIG. 2 is a schematic view of the use position of a flexible marker in one embodiment of the present invention;
FIG. 3 is a right side view of FIG. 2;
FIG. 4 is a schematic diagram of a photographing orientation of a camera according to an embodiment of the invention;
reference numerals: 1. a test piece; 2. a strain gauge; 3. a flexible marker; 4. a camera; 31. an inner circular ring; 32. a first outer ring; 33. a second outer circular ring.
Detailed Description
The technical solution of the present invention will be further described in detail with reference to the accompanying drawings and the detailed description. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the invention without making creative efforts, shall fall within the scope of the claimed invention.
As shown in fig. 1, which is a specific embodiment of the flexible marker of the present invention, the flexible marker 3 is provided with a plurality of encoding points with unique identity information, which is easy to detect, and at the same time, ensures that the flexible marker 3 has rotation, translation and scale invariance, and has the function of facilitating automatic detection, identification and measurement of the flexible marker 3 from an image.
The encoding points of the flexible marker 3 in this embodiment are concentric ring type encoding points, which include three concentric rings, an inner ring 31, a first outer ring 32, and a second outer ring 33. The inner ring 31 is a solid circular portion, the first outer ring 32 is a spacer ring, and the second outer ring 33 is a code strip. The method is characterized in that a binary coding principle is adopted, a coding band is equally divided into n equal parts, each equal part represents a binary digit, the black is 0, the white is 1, and n-bit binary digits are formed in the clockwise direction. The binary numbers correspond to decimal numbers, and the minimum decimal value is selected as the code value of the code mark point, and the code value is determined uniquely. It should be noted that, according to actual needs, the encoding point of the flexible marker 3 may also be in other forms, such as a regular polygon, five concentric rings, and other schemes, as long as the conditions that the detection is easy and the flexible marker 3 has rotation, translation, and scale invariance are satisfied.
A specific embodiment of a non-contact positioning method for a space coordinate of a resistance strain gauge, which adopts the flexible marker 3, includes the following steps:
the method comprises the following steps of firstly, carrying out scheme design and measurement preparation.
The test scheme is preliminarily determined according to the size of the object to be tested, and the test scheme in the specific embodiment includes determining a shooting range, a lens model, a mark point size and camera parameters, and may further include other contents according to actual needs. The shooting range is determined based on the shape and size of the object to be measured, and the shooting object is generally preferably used to occupy the whole shooting area. In this embodiment, the structural photogrammetry is performed in a manner of local photography and overall calculation.
Second, the flexible marker 3 is designed from the strain gauge 2.
As shown in fig. 2 to 3, in the present embodiment, a flexible marker 3 specially designed for identifying the strain gauge 2 is adopted, the flexible marker 3 is disposed on one side of the strain gauge 2 away from the test piece 1, and some encoding points with unique identity information are designed on the flexible marker 3, which is not only easy to detect, but also ensures that the flexible marker 3 has rotation, translation and scale invariance, so as to realize automatic detection, identification and measurement of the flexible marker 3 from an image.
The encoding points of the flexible marker 3 in this embodiment are concentric ring type encoding points, which include three concentric rings, an inner ring 31, a first outer ring 32, and a second outer ring 33. The inner ring 31 is a solid circular portion, the first outer ring 32 is a spacer ring, and the second outer ring 33 is a code strip. In this embodiment, a binary coding principle is adopted, and a coding band is equally divided into n equal parts, each equal part represents a binary digit, black is 0, white is 1, and n-bit binary digits are formed in a clockwise direction. The binary numbers correspond to decimal numbers, and the minimum decimal value is selected as the code value of the code mark point, and the code value is determined uniquely. The decimal number corresponding to the code of the code point in this particular embodiment is located in the upper left corner of the flexible marker 3, and this number is consistent with the number of the strain gauge 2 in the test system. The code strip shown in fig. 3 is a fifteen-bit code symbol point, represented as 000001010111111, corresponding to the decimal number 8. In the specific embodiment, the binary number and the decimal number are in a corresponding relation through a code lookup table, and the corresponding rule can be set by a programmer or determined randomly as long as uniqueness is ensured.
And thirdly, adhering the strain gauge 2 and the flexible marker 3.
Since the flexible marker 3 is adhered to the surface of the strain gauge 2, the flexible marker 3 has sufficient flexibility. In this embodiment, the designed flexible marker 3 is made on a paper-based material and then adhered to the surface of the strain gauge 2. According to the manufacturing and pasting process of the strain gauge 2, the strain gauge 2 is provided with a centering baseline, the centering baseline is pasted after being centered with a scribed line on the surface of the test piece 1 during pasting, the centering baseline is also manufactured at the centers of four sides of the flexible marker 3, namely after the three baselines are centered, the flexible marker 3 is pasted on the surface of the strain gauge 2.
And fourthly, shooting a digital image.
In this embodiment, the structural photogrammetry is performed in a manner of local photography and overall calculation. The whole measurement scheme is to carry out uniform shooting measurement around the structure and carry out key shooting aiming at key parts. Because the measured object is a cylinder, all measured target points cannot be obtained through one measuring station, and a non-collinear point needs to be additionally added in two measurements, as shown in fig. 4, a schematic diagram of the photographing direction of the camera is shown, two cameras 4 are adopted in each measurement shown in the diagram, and three non-collinear common points exist in the two measurements.
And fifthly, processing data.
In the process of measuring the three-dimensional topography, in order to automatically and efficiently extract the image characteristics of the surface of a measuring object, the accurate identification and positioning of the mark points are the primary tasks of measurement, and the identification process generally comprises image preprocessing, whole pixel edge extraction, mark point characteristic screening, center sub-pixel positioning, encoding point decoding and the like.
The image preprocessing is actually a process of weighted average of the image, and the gray value of each pixel point is obtained by weighted average of the gray value and other gray values in the neighborhood. And obtaining the edge of the image based on a Canny operator, and screening according to the inherent characteristics of the mark points. In the specific embodiment, a boundary closing criterion, a size criterion, a roundness criterion and a position criterion are formulated to screen the targets. The criteria for screening targets are set according to actual needs, and the list in this embodiment is for illustration only.
Due to perspective projection, the geometry of the image of the circular marker on the target surface of the camera 4 is generally elliptical. The present embodiment finds the correlation coefficient of the elliptic equation based on a least square fitting method. The general equation form of an ellipse is as follows:
x2+Axy+By2+Cx+Dy+E＝0
according to the multi-view geometrical relationship in computer vision, when the internal reference of the camera 4 and the external reference relative to the world coordinate system are known, the three-dimensional coordinates of the space point can be calculated only by acquiring the pixel coordinates of the space point in two or more than two photos.
In the embodiment, according to the data information obtained by shooting, calculation such as coordinate calculation is performed through computer processing and analysis, and finally accurate position information of the strain gauge is obtained.
Therefore, the space coordinate non-contact type positioning of the large-scale structure test resistance strain gauge is completed.
The beneficial technical effects obtained by the specific embodiment are as follows:
compared with the prior art, the embodiment designs and manufactures the flexible marker 3 which can be used for image recognition, sticks the flexible marker on the surface of the resistance strain gauge 2, obtains the image coordinates of the flexible marker through an image processing technology, and calculates the space coordinates of the strain gauge 2 through three-dimensional reconstruction and the like. The novel space positioning method for the resistance strain gauge in the large-scale structure test is realized, and the measurement and acquisition of the space coordinates of the resistance strain gauge in the general large-scale structure test can be met.
The verification proves that the method is stable and reliable, the measurement efficiency is greatly improved compared with a manual method when the space position of the large-scale structural test resistance strain gauge 2 is measured, compared with the traditional image identification method for directly identifying the resistance strain gauge 2, the method is convenient to identify, unique in serial number, accurate in positioning and identification, automatic in subsequent solving and conversion processes, accurate and reliable in result, solves the problems in the prior art, and has outstanding substantive characteristics and remarkable progress.
Claims (10)
1. A flexible marker, characterized by: the flexible marker (3) is designed with a plurality of coding points, and the flexible marker (3) has rotation, translation and scale invariance.
2. The flexible marker of claim 1, wherein: the encoding points of the flexible marker (3) are concentric ring type encoding points, and the concentric ring type encoding points comprise three concentric rings which are respectively an inner ring (31), a first outer ring (32) and a second outer ring (33). The inner ring (31) is a solid circular part, the first outer ring (32) is a spacer ring, and the second outer ring (33) is an encoding band.
3. The flexible marker of claim 2, wherein: the flexible marker (3) is characterized in that a binary coding principle is adopted, a coding band is equally divided into n equal parts, each equal part represents a binary digit, the black is 0, the white is 1, n binary digits are formed in the clockwise direction, the binary digits correspond to decimal numbers, the minimum decimal value is selected as the coding value of the coding mark point, and the coding value is uniquely determined.
4. The flexible marker of claim 3, wherein: the flexible marker (3) is also provided with a decimal number corresponding to the code of the code point.
5. The flexible marker of claim 3, wherein: the flexible marker (3) divides the code band equally into fifteen equal parts.
6. A method for non-contact positioning of space coordinates of a resistance strain gauge, which comprises a test piece (1), the strain gauge (2) and a camera (4), and is characterized in that a flexible marker (3) according to any one of claims 1-5 is adopted, the flexible marker (3) is arranged on one side of the strain gauge (2) far away from the test piece (1), and the method comprises the following steps:
firstly, carrying out scheme design and measurement preparation;
secondly, designing a flexible marker (3) according to the strain gauge (2);
thirdly, adhering the strain gauge (2) and the flexible marker (3);
fourthly, shooting a digital image by using a camera (4);
fifthly, processing data;
therefore, the space coordinate non-contact type positioning of the large-scale structure test resistance strain gauge is completed.
7. The method for non-contact positioning of the spatial coordinates of the resistance strain gauge according to claim 6, wherein the method comprises the following steps: and when the strain gauge (2) and the flexible marker (3) are adhered in the third step, the designed flexible marker (3) is manufactured on a paper-based material and then is adhered to the surface of the strain gauge (2), the strain gauge (2) is provided with a centering base line and is adhered after being centered with a scribed line on the surface of the test piece (1) during adhering, the centering base line is also manufactured at the centers of four sides of the flexible marker (3), namely after the three base lines are centered, the flexible marker (3) is adhered to the surface of the strain gauge (2).
8. The method for non-contact positioning of the spatial coordinates of the resistance strain gauge according to claim 7, wherein the method comprises the following steps: and in the fourth step, the digital image is shot in a mode of local photography and integral calculation, the integral measurement scheme is that the measurement is uniformly shot around the structure, key shooting is carried out on key parts, and a non-collinear point is additionally added in the two measurements.
9. The method for non-contact positioning of the spatial coordinates of the resistance strain gauge according to claim 8, wherein the method comprises the following steps: and when data processing is carried out in the fifth step, the identification process comprises image preprocessing, whole pixel edge extraction, mark point feature screening, center sub-pixel positioning and coding point decoding, the image preprocessing obtains the edge of the image based on a Canny operator, screening is carried out according to inherent features of mark points, the image preprocessing comprises a boundary closing criterion, a size criterion, a roundness criterion and a position criterion, and when the geometric shape of the image formed by the circular mark on the target surface of the camera (4) is an ellipse, the correlation coefficient of an ellipse equation is solved based on a least square fitting mode.
10. The method for non-contact positioning of the spatial coordinates of the resistance strain gauge according to claim 1, wherein the method comprises the following steps: use of a flexible marker (3) according to claim 4, the flexible marker (3) having a coded dot coded with a decimal number corresponding to the strain gauge (2) number in the test system.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09189513A (en) * | 1996-01-10 | 1997-07-22 | Kawasaki Heavy Ind Ltd | Marker gravity center measurement method and device |
| CN101566465A (en) * | 2009-05-18 | 2009-10-28 | 西安交通大学 | Method for measuring object deformation in real time |
| CN103310215A (en) * | 2013-07-03 | 2013-09-18 | 天津工业大学 | Detecting and identifying method for annular coding mark point |
| CN105424721A (en) * | 2015-12-11 | 2016-03-23 | 南京神源生智能科技有限公司 | Metal strain gauge defect automatic detection system |
| CN107816950A (en) * | 2017-10-18 | 2018-03-20 | 苏州汇才土水工程科技有限公司 | Specimen surface warped digital image measuring apparatus and method based on sub-pix corner recognition |
| CN109285198A (en) * | 2018-08-22 | 2019-01-29 | 大连理工大学 | A kind of coding of annular coded markings point and recognition methods |
-
2021
- 2021-04-15 CN CN202110403570.5A patent/CN113188440A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09189513A (en) * | 1996-01-10 | 1997-07-22 | Kawasaki Heavy Ind Ltd | Marker gravity center measurement method and device |
| CN101566465A (en) * | 2009-05-18 | 2009-10-28 | 西安交通大学 | Method for measuring object deformation in real time |
| CN103310215A (en) * | 2013-07-03 | 2013-09-18 | 天津工业大学 | Detecting and identifying method for annular coding mark point |
| CN105424721A (en) * | 2015-12-11 | 2016-03-23 | 南京神源生智能科技有限公司 | Metal strain gauge defect automatic detection system |
| CN107816950A (en) * | 2017-10-18 | 2018-03-20 | 苏州汇才土水工程科技有限公司 | Specimen surface warped digital image measuring apparatus and method based on sub-pix corner recognition |
| CN109285198A (en) * | 2018-08-22 | 2019-01-29 | 大连理工大学 | A kind of coding of annular coded markings point and recognition methods |
Non-Patent Citations (1)
| Title |
|---|
| 王智勇等: "热结构高温应变光学测量技术发展探讨", 《强度与环境》 * |
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