CN110806182A - High-precision optical extensometer and measuring method based on telecentric lens - Google Patents
High-precision optical extensometer and measuring method based on telecentric lens Download PDFInfo
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- CN110806182A CN110806182A CN201911042917.7A CN201911042917A CN110806182A CN 110806182 A CN110806182 A CN 110806182A CN 201911042917 A CN201911042917 A CN 201911042917A CN 110806182 A CN110806182 A CN 110806182A
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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
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
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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
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
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Abstract
The invention discloses a high-precision optical extensometer and a measuring method based on a telecentric lens. The measuring method uses a digital camera and a telecentric lens to track a target point, and can eliminate false displacement and false strain caused by the out-of-plane displacement of the surface of a sample and a single-camera pinhole imaging model by virtue of the imaging characteristic of the telecentric lens which is insensitive to depth, thereby greatly improving the in-plane displacement and strain measurement precision of the sample.
Description
Technical Field
The invention relates to a high-precision optical extensometer based on a telecentric lens and a measuring method, belonging to the field of optical measurement and nondestructive testing.
Background
Strain measurement is one of the important targets in the fields of structural failure analysis, material performance detection, industrial deformation monitoring and the like, and the traditional strain measurement technology mainly comprises contact and non-contact measurement technologies.
Contact measurement techniques such as resistance strain gauges, optical fiber strain gauges or mechanical extensometers and the like often add additional mass to a measured sample, and the use of adhesives can strengthen the sample to a certain extent, so that the measurement modes are increasingly unsuitable for detection of samples such as biological materials, thin film materials and the like.
In the non-contact measurement technology, the strain detection precision of the two-dimensional and three-dimensional digital image correlation technology for full-field measurement still needs to be improved, and more video extensometers based on optical methods, such as the commercialized video extensometers of the Instron company, have appeared at present, and the strain measurement precision cannot meet the requirements of practical application. More importantly, a sample generates certain out-of-plane displacement under actual experimental conditions due to various reasons, and the out-of-plane displacement generates false displacement and false strain on an image plane of an imaging system under the condition of a traditional pinhole imaging model, so that the precision and the resolution of a strain measurement result are greatly interfered.
Aiming at the problem, the Baipeng flying et al provides a strain correction method in 2015, and extra correction pieces are needed to be added under a pinhole model to ensure higher precision.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a high-precision optical extensometer and a measuring method based on a telecentric lens and multiple reflectors. The optical extensometer and the measuring method are used for uniform strain detection, so that false displacement and false strain caused by the out-of-plane displacement of a measured sample can be effectively eliminated on the basis of using a single camera and a single image chip, and the precision and the resolution of uniform strain measurement are improved.
The invention adopts the following technical scheme for solving the technical problems:
the invention provides a high-precision optical extensometer based on a color camera, which comprises a digital camera, a telecentric lens, four reflectors, a camera bracket for bearing the digital camera and a data processing device, wherein the digital camera is arranged on the digital camera bracket; wherein the content of the first and second substances,
the four reflectors are arranged between the telecentric lens and the sample to be detected, and the diffused light field on each target point on the surface of the sample to be detected is reflected twice by the two reflectors in sequence and then is incident into the telecentric lens in a direction parallel to the optical axis of the telecentric lens;
the telecentric lens images the two target points on the surface of the sample to be detected by receiving the diffused light fields on the two reflected target points to form digital images of the two target points;
the digital camera shoots digital images of two target points simultaneously and transmits the shot digital images to the data processing module, and the light field information of each target point respectively occupies half of the frame of the digital camera image chip, namely the two target points in the shot digital images respectively occupy half, so as to realize the simultaneous acquisition of the digital images of the two target points;
the data processing device comprises a correlation operation module and a post-processing module, wherein the correlation operation module acquires displacement information of two target points along the measuring direction according to the received digital image; the post-processing module obtains local uniform strain information of the surface of the tested sample by utilizing the displacement information obtained by the relevant operation module and combining the distance information of the two target points.
As a further technical scheme of the invention, the telecentric lens is an object-side telecentric or double telecentric lens.
As a further technical scheme of the invention, the uniform strain of the surface of the tested sample is (x)2-x1)/s，x1And x2Respectively, the displacement of the first and second target points along the measuring direction, and s is the distance between the first and second target points.
The invention also provides a uniform strain measurement method based on the high-precision optical extensometer based on the color camera, which comprises the following steps:
(1) selecting two target points on the surface of a sample to be measured as measuring points, wherein the connecting line direction of the two target points is the measuring direction, and manually generating random speckles at the target points or using the surface texture of the sample as a carrier of deformation information;
(2) mounting a digital camera and a telecentric lens on a camera bracket, and enabling the optical axis of the telecentric lens to be vertical to the surface of the detected sample;
(3) installing four reflectors to enable the diffused light fields on the two target points to enter a telecentric lens and a digital camera for imaging after twice reflection, ensuring that the diffused light fields and the digital camera are not interfered with each other, and enabling the light field information of each target point to respectively occupy half of the frame of an image chip of the digital camera;
(4) the positions of the four reflectors and the digital camera are finely adjusted, so that the optical distances from the two target points to the telecentric lens after twice reflection are equal, and the digital camera can clearly image the two target points at the same time;
(5) respectively obtaining the displacement x of two target points along the measuring direction according to the digital image obtained by the digital camera1And x2Combining the distance s between the two target points to calculate the uniform strain of the surface of the measured sample as (x)2-x1)/s。
Compared with the prior art, the invention adopting the technical scheme has the following technical effects:
(1) the surface of the tested sample is not damaged: compared with the traditional contact type measuring technology represented by a strain gauge in the industrial field, the invention adopts the optical measuring technology, does not need to be in direct contact with the surface of a sample, has no additional mass, does not damage the sample and does not limit the deformation of the sample;
(2) the influence of the out-of-plane displacement of the surface of the sample is eliminated: the arrangement of the four reflectors can enable the light field information of two target points far away from each other to be reflected twice, the light field information is drawn to a close distance in space and combined to be incident into the telecentric lens, the telecentric lens has the characteristic of insensitivity to depth information within a certain range, so that the target points do not generate false displacement on the image surface of the digital camera due to out-of-plane displacement to a certain extent, and the strain calculated according to the displacement does not contain false strain, so that the false displacement and the false strain caused by the out-of-plane displacement which is inevitably generated by a sample in the measuring process are eliminated, and a foundation is provided for improving the measuring precision;
(3) the precision is improved: compared with the single-camera measurement of uniform strain based on a vacuum imaging model, the measurement precision is greatly improved; the field of view and the resolution ratio are a pair of contradictory factors in the single-camera measurement based on the vacuum imaging model, a large field of view range is wasted, the measurement gauge length is limited, the measurement precision of uniform strain is limited, the selection of the position of a target point is more flexible due to the use of four reflectors, and the measurement gauge length is not limited any more while the displacement measurement precision is ensured, so that the measurement precision of uniform strain is greatly improved;
(4) using only a single camera: compared with an imaging system using multiple cameras or multiple image chips, the single camera using only one single image chip avoids the problem of time delay when multiple pieces of hardware acquire digital images and the problem of camera synchronization of hardware or software.
Drawings
Fig. 1 is a schematic view of the measurement of an optical extensometer according to the present invention.
In the figure: 1-sample to be measured, 2-two target points, 3-digital camera, 4-telecentric lens, 5-camera support for carrying digital camera, 6-first reflector, 7-second reflector, 8-third reflector, 9-fourth reflector.
FIG. 2 is a schematic diagram illustrating the principle of eliminating out-of-plane displacement in the method of the present invention.
Detailed Description
The technical scheme of the invention is further explained in detail by combining the attached drawings:
as shown in fig. 1, the embodiment of the present invention discloses a high-precision optical extensometer based on a telecentric lens and multiple reflectors, which comprises a reflector 6 and a reflector 7 corresponding to a target point, a reflector 8 and a reflector 9 corresponding to another target point, a digital camera 3, a telecentric lens 4, a camera support 5 and a data processing device. Firstly, selecting two target points 2 of an optical extensometer on a sample 1 to be measured, dividing four reflectors 6, 7, 8 and 9 into two groups 6, 7 and 8 and 9, arranging the reflectors 6 and 7 to form an angle of about 45 degrees with the surface of the sample 1 to be measured, and enabling the reflector 6 to correspond to the first target point; the mirrors 8, 9 are positioned at approximately 45 degrees to the surface of the sample 1 being measured and the mirror 9 corresponds to a second target point. A telecentric lens 4 and a digital camera 3 are arranged on a camera bracket 5, the telecentric lens 4 is used for imaging two target points on the surface of the measured sample 1, and the measurement system error caused by the out-of-plane displacement of the measured sample 1 is eliminated by virtue of the characteristic that the telecentric lens 4 is insensitive to depth information. The digital camera 3 is used for simultaneously shooting digital images of two target points 2 on the surface of a detected sample 1, and light field information of the two target points 2 respectively occupies half of the picture of an image chip of the digital camera 3, namely the two target points 2 in the shot digital images respectively occupy half of the picture, so that the digital images of the two target points are simultaneously collected. The bracket 5 capable of bearing the digital camera ensures that the digital camera 3 can be stably borne, so that the position of the digital camera 3 can be adjusted within a certain range. The data processing device comprises a correlation operation module and a post-processing module. The correlation operation module is used for performing digital image correlation operation on the digital image acquired by the digital camera to acquire displacement information of two target points; the post-processing module utilizes the displacement information obtained by the relevant operation module and combines the distance information of the two target points to calculate so as to obtain the uniform strain information of the surface of the tested sample 1.
The embodiment of the invention discloses a high-precision optical extensometer and a measuring method based on a telecentric lens and a plurality of reflectors, which can eliminate false displacement and false strain contained in a measuring result caused by out-of-plane displacement generated on the surface of a measured sample, and the principle of the generation of the false displacement and the strain is shown in figure 2. An ordinary camera and a lens without a telecentric lens generally follow a pinhole imaging model when imaging, for example, if a target point is set as a point A far from an optical axis on the surface of a sample to be measured in FIG. 2, the point A on an image surface can be imaged through the lens. When the surface of the detected sample generates a certain degree of out-of-plane displacement to enable the point A to move to the point B, imaging is carried out on the point B which has a certain distance with the point a on the image surface according to the pinhole imaging model. Under the condition that the measured sample is not deformed, the displacement of the imaging point formed by the same point on the image plane is generated only because the surface of the measured sample generates out-of-plane displacement, the size of the displacement is the distance between the point a and the point b, and corresponding strain data can be calculated according to the displacement data, namely false displacement and false strain caused by the out-of-plane displacement. If the common lens is replaced by the telecentric lens, due to the characteristic that the telecentric lens is insensitive to depth information, after the point A is moved to the point B, the position of an imaging point on the image surface is unchanged, namely, a target point does not generate displacement on the image surface, which means that the out-of-plane displacement does not cause false displacement and subsequent false strain, and the measurement precision can be naturally improved.
The embodiment of the invention discloses a uniform strain measurement method based on a high-precision optical extensometer, which comprises the following steps:
step 1, selecting two target points on the surface of a sample to be measured as measuring points, wherein the connecting line direction of the two target points is the measuring direction, and manually generating random speckles at the target points or using the surface texture of the sample as a carrier of deformation information;
step 2, mounting the digital camera and the telecentric lens on a camera bracket, and enabling the optical axis of the telecentric lens to be vertical to the surface of the tested sample;
step 4, fine adjustment is carried out on the positions of the four reflectors and the digital camera, the optical distances from the two target points to the telecentric lens after twice reflection are equal, and the digital camera can simultaneously carry out clear imaging on the two target points;
step 5, respectively obtaining the displacement x generated by the two target points along the measuring direction according to the digital image obtained by the digital camera1And x2And calculating the uniform strain magnitude of the surface of the measured sample to be (x2-x1)/s by combining the distance s between the two target points.
Compared with the traditional single camera, the distance between the two groups of reflectors is also the distance between the two target points, and simultaneously, the strain measurement gauge length is adjustable according to the actual requirement, so that the device has higher flexibility. The distance between the two target points is directly related to the strain measurement precision, the strain measurement gauge length can be enlarged by increasing the distance between the two target points, and the precision and the resolution of the strain measurement can be greatly increased under the condition that the relative displacement precision is fixed and unchanged.
The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all should be considered as belonging to the protection scope of the invention.
Claims (4)
1. A high-precision optical extensometer based on a telecentric lens and a plurality of reflectors is characterized by comprising a digital camera, a telecentric lens, four reflectors, a camera bracket for bearing the digital camera and a data processing device; wherein the content of the first and second substances,
the four reflectors are arranged between the telecentric lens and the sample to be detected, and the diffused light field on each target point on the surface of the sample to be detected is reflected twice by the two reflectors in sequence and then is incident into the telecentric lens in a direction parallel to the optical axis of the telecentric lens;
the telecentric lens images the two target points on the surface of the sample to be detected by receiving the diffused light fields on the two reflected target points to form digital images of the two target points; the digital camera shoots digital images of two target points simultaneously and transmits the shot digital images to the data processing module, and the light field information of each target point respectively occupies half of the frame of the digital camera image chip, namely the two target points in the shot digital images respectively occupy half, so as to realize the simultaneous acquisition of the digital images of the two target points;
the data processing device comprises a correlation operation module and a post-processing module, wherein the correlation operation module acquires displacement information of two target points along the measuring direction according to the received digital image; the post-processing module obtains local uniform strain information of the surface of the tested sample by utilizing the displacement information obtained by the relevant operation module and combining the distance information of the two target points.
2. A high accuracy optical extensometer based on telecentric optics and multiple mirrors according to claim 1 characterized in that the telecentric optics is an object-side telecentric or double telecentric optics.
3. A telecentric lens and multi-mirror based high-precision optical extensometer according to claim 1, characterized in that the uniform strain magnitude of the measured sample surface is (x)2-x1)/s，x1And x2Respectively, the displacement of the first and second target points along the measuring direction, and s is the distance between the first and second target points.
4. A method for measuring uniform strain based on a dual-camera high-precision optical extensometer as claimed in any one of claims 1 to 3, characterized by comprising the following steps:
(1) selecting two target points on the surface of a sample to be measured as measuring points, wherein the connecting line direction of the two target points is the measuring direction, and manually generating random speckles at the target points or using the surface texture of the sample as a carrier of deformation information;
(2) mounting a digital camera and a telecentric lens on a camera bracket, and enabling the optical axis of the telecentric lens to be vertical to the surface of the detected sample;
(3) installing four reflectors to enable the diffused light fields on the two target points to enter a telecentric lens and a digital camera for imaging after twice reflection, ensuring that the diffused light fields and the digital camera are not interfered with each other, and enabling the light field information of each target point to respectively occupy half of the frame of an image chip of the digital camera;
(4) the positions of the four reflectors and the digital camera are finely adjusted, so that the optical distances from the two target points to the telecentric lens after twice reflection are equal, and the digital camera can clearly image the two target points at the same time;
(5) respectively obtaining the displacement x of two target points along the measuring direction according to the digital image obtained by the digital camera1And x2Combining the distance s between the two target points to calculate the uniform strain of the surface of the measured sample as (x)2-x1)/s。
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111829446A (en) * | 2020-07-09 | 2020-10-27 | 河海大学 | High-precision double-axis optical extensometer using plurality of rhombic prisms |
| CN111829445A (en) * | 2020-07-09 | 2020-10-27 | 河海大学 | High-precision optical extensometer based on double prisms |
| CN111964600A (en) * | 2020-07-28 | 2020-11-20 | 河海大学 | High-precision biaxial optical extensometer and measuring method based on bidirectional view field separation |
| CN112414315A (en) * | 2020-12-21 | 2021-02-26 | 常州信息职业技术学院 | Precision measurement device and method for part positioning distance |
| CN112525096A (en) * | 2020-11-30 | 2021-03-19 | 上海大学 | Double-telecentric-lens video extensometer based on field segmentation |
| CN113390337A (en) * | 2021-06-03 | 2021-09-14 | 合肥工业大学 | X-Y-theta three-degree-of-freedom measuring method based on field separation |
| CN113739700A (en) * | 2020-12-25 | 2021-12-03 | 深圳市中图仪器股份有限公司 | Method for adjusting orthogonal axis system of coordinate measuring instrument |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2526188A1 (en) * | 1975-06-12 | 1976-12-30 | Mueller Falkenberg Konrad | Contactless measurement of length - is for tensile test equipment and uses optical detectors for flexibility and minimal equipment |
| JP2000161927A (en) * | 1998-11-30 | 2000-06-16 | Shimadzu Corp | Video-type extensometer |
| US6094259A (en) * | 1997-09-18 | 2000-07-25 | Shimadzy Corporation | Optical extensometer and reference line mark therefor |
| CN1837747A (en) * | 2006-02-27 | 2006-09-27 | 王化谦 | Double-camera video frequency large-deformation measurement method and video frequency extension device based thereon |
| US20090225167A1 (en) * | 2008-03-10 | 2009-09-10 | Shimadzu Corporation | Gauge line position measuring device, program for measuring a gauge line position, and gauge line mark |
| CN101943604A (en) * | 2009-09-30 | 2011-01-12 | 卢家金 | Temperature-measurement imaging system and measuring method thereof |
| CN105758719A (en) * | 2016-04-26 | 2016-07-13 | 河海大学 | Homogeneous strain optical measurement device based on double-mirror reflection and method |
| CN109556528A (en) * | 2018-10-30 | 2019-04-02 | 南京理工大学 | A kind of one camera 3 D video extensometer and measurement method |
-
2019
- 2019-10-30 CN CN201911042917.7A patent/CN110806182A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2526188A1 (en) * | 1975-06-12 | 1976-12-30 | Mueller Falkenberg Konrad | Contactless measurement of length - is for tensile test equipment and uses optical detectors for flexibility and minimal equipment |
| US6094259A (en) * | 1997-09-18 | 2000-07-25 | Shimadzy Corporation | Optical extensometer and reference line mark therefor |
| JP2000161927A (en) * | 1998-11-30 | 2000-06-16 | Shimadzu Corp | Video-type extensometer |
| CN1837747A (en) * | 2006-02-27 | 2006-09-27 | 王化谦 | Double-camera video frequency large-deformation measurement method and video frequency extension device based thereon |
| US20090225167A1 (en) * | 2008-03-10 | 2009-09-10 | Shimadzu Corporation | Gauge line position measuring device, program for measuring a gauge line position, and gauge line mark |
| CN101943604A (en) * | 2009-09-30 | 2011-01-12 | 卢家金 | Temperature-measurement imaging system and measuring method thereof |
| CN105758719A (en) * | 2016-04-26 | 2016-07-13 | 河海大学 | Homogeneous strain optical measurement device based on double-mirror reflection and method |
| CN109556528A (en) * | 2018-10-30 | 2019-04-02 | 南京理工大学 | A kind of one camera 3 D video extensometer and measurement method |
Non-Patent Citations (2)
| Title |
|---|
| BO DONG 等: "Ultrasensitive video extensometer using single-camera dual field-of-view telecentric imaging system", 《OPTICS LETTERS》 * |
| 俞立平等: "使用单个单反相机的三维数字图像相关测量***", 《北京力学会第24届学术年会》 * |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111829446A (en) * | 2020-07-09 | 2020-10-27 | 河海大学 | High-precision double-axis optical extensometer using plurality of rhombic prisms |
| CN111829445A (en) * | 2020-07-09 | 2020-10-27 | 河海大学 | High-precision optical extensometer based on double prisms |
| CN111964600A (en) * | 2020-07-28 | 2020-11-20 | 河海大学 | High-precision biaxial optical extensometer and measuring method based on bidirectional view field separation |
| CN112525096A (en) * | 2020-11-30 | 2021-03-19 | 上海大学 | Double-telecentric-lens video extensometer based on field segmentation |
| CN112414315A (en) * | 2020-12-21 | 2021-02-26 | 常州信息职业技术学院 | Precision measurement device and method for part positioning distance |
| CN113739700A (en) * | 2020-12-25 | 2021-12-03 | 深圳市中图仪器股份有限公司 | Method for adjusting orthogonal axis system of coordinate measuring instrument |
| CN113739700B (en) * | 2020-12-25 | 2023-09-01 | 深圳市中图仪器股份有限公司 | Method for adjusting orthogonal axis system of coordinate measuring instrument |
| CN113390337A (en) * | 2021-06-03 | 2021-09-14 | 合肥工业大学 | X-Y-theta three-degree-of-freedom measuring method based on field separation |
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Application publication date: 20200218 |