CN114322812A - Monocular three-dimensional high-speed measurement method, optical path system and calibration method thereof - Google Patents
Monocular three-dimensional high-speed measurement method, optical path system and calibration method thereof Download PDFInfo
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Abstract
The invention belongs to the technical field of measurement technology and three-dimensional vision, and particularly relates to a monocular three-dimensional high-speed measurement method, an optical path system and a calibration method thereof; the method comprises the steps of collecting a first virtual image and a second virtual image of a tested sample on the basis of a monocular measuring unit; the first virtual image and the second virtual image are used for observing the three-dimensional strain of the tested sample, so that an optical path system in three-dimensional strain measurement based on a three-dimensional DIC algorithm can be simplified, the structure of a three-dimensional strain detection system is simplified, and the detection efficiency is improved.
Description
Technical Field
The invention belongs to the technical field of measurement and three-dimensional vision, and particularly relates to a monocular three-dimensional high-speed measurement method, an optical path system and a calibration method thereof.
Background
At present, the detection of deformation in mechanical properties is very popular, and the detection of deformation can be applied to the strain test detection of various materials and structures, on one hand, the detection can be used for ensuring the qualified product quality, and on the other hand, the detection can be used for verifying the rationality of material and structure design. Therefore, how to accurately and efficiently detect the deformation becomes more and more important.
Currently, in deformation detection, a conventional measurement system based on a DIC technology (Digital Image Correlation, also called Digital speckle Correlation) generally adopts the following two schemes:
the measurement system adopts a binocular image acquisition device and is matched with a binocular three-dimensional DIC algorithm.
For example, patent document 1 discloses a method for implementing a digital speckle-based visual extensometer, and as shown in fig. 1, a binocular image acquisition measurement system is used for measuring three-dimensional strain of a material, and the measurement system is not only complicated in structure, but also requires two independent light sources and a CCD camera. Moreover, the two light sources need to be independently placed, and the sample is obliquely irradiated from two angles, so that the light field brightness of the sample is difficult to be uniform, for example, when the sample is large, the light field brightness in the middle and the left and right sides of the sample is extremely non-uniform, and data loss is caused.
And the other is a measuring system based on a monocular image acquisition device and matched with a two-dimensional DIC algorithm.
For example, patent document 2 discloses a method for using a two-dimensional extensometer based on structured light, which is shown in fig. 2, and is used for processing and analyzing images acquired by a single camera and a lens, and can only measure strain in two-dimensional directions, and thus cannot meet the measurement requirement of three-dimensional data. And the light source is arranged on the left side of the camera and the lens, and when the exposure time required in the measurement process is short, the brightness on the left side and the right side of the sample is uneven, so that data loss occurs on the part with dark brightness.
Therefore, in the prior art, there is no related optical path scheme that can be used with a monocular three-dimensional DIC algorithm to perform three-dimensional strain measurement, and therefore a new measurement system that can be used for three-dimensional strain detection based on a three-dimensional DIC algorithm is needed.
Documents of the prior art
Patent document
Patent document 1: china invention number CN 103575227A
Patent document 2: china invention number CN 111426280A
Disclosure of Invention
In view of this, the present invention provides a monocular three-dimensional high-speed measurement method, which is performed based on a first virtual image and a second virtual image of a sample to be measured, which are acquired by a monocular measurement unit; the first virtual image and the second virtual image are used for observing the three-dimensional strain of the tested sample, so that an optical path system in three-dimensional strain measurement based on a three-dimensional DIC algorithm can be simplified, the structure of a three-dimensional strain detection system is simplified, and the detection efficiency is improved.
In order to achieve the technical purpose, the invention adopts the following specific technical scheme:
a monocular three-dimensional high-speed measurement method is carried out on the basis of a first virtual image and a second virtual image of a sample to be measured, which are acquired by a monocular measurement unit; the first virtual image and the second virtual image are used for observing three-dimensional strain of the tested sample;
the measuring method comprises the following steps:
s101: identifying base pixel features of the first and second virtual images;
s102: dividing and defining the basic pixel characteristics into a plurality of strain subareas;
s103: acquiring pixel characteristics in the first virtual image and the second virtual image during and/or after the strain process of the tested sample to generate strain pixel characteristics;
s104: separating a plurality of regions to be calculated from at least one part of the strain subarea;
s105: extracting strain pixel characteristics of a region corresponding to each region to be calculated;
s106: comparing the extracted strain pixel characteristics of the area corresponding to each area to be calculated with the basic pixel characteristics to obtain the motion step length of each area to be calculated;
s107: based on each of the motion steps, a full field strain of the sample under test is calculated.
Further, regularly arranged speckles are arranged on the outer surface of the sample to be tested; the base pixel features and the strain pixel features are both obtained based on the speckle.
Further, in S107, a sub-pixel displacement measurement algorithm is adopted to calculate the full-field strain of the measured sample.
The invention also provides an optical path system for realizing the monocular three-dimensional high-speed measurement method, which comprises the following steps: the device comprises a first light source, a first reflector, a second light source, a second reflector and a triangular prism;
the triangular prism is arranged between the first reflective mirror and the second reflective mirror, and a sample to be tested is placed in front of the triangular prism;
the first light source is arranged on one side of the first reflector, which is far away from the triangular prism, and is used for emitting light rays to generate first reflected light rays on the surface of the sample to be tested;
the second light source is arranged on one side of the second reflector, which is far away from the triangular prism, and is used for emitting light rays to generate second reflected light rays on the surface of the sample to be tested;
the first reflector is used for reflecting the first reflected light to the first mirror surface of the triangular prism;
the second reflector is used for reflecting the second reflected light to the second mirror surface of the triangular prism;
the first mirror surface of triangular prism is used for with first reflection light forms the first virtual image that is tested the sample and corresponds, the second mirror surface of triangular prism is used for with second reflection light forms the second virtual image that is tested the sample and corresponds.
Further, the optical path system further comprises a monocular acquisition unit, and the monocular acquisition unit is used for acquiring the first virtual image and the second virtual image.
Further, the optical path system further includes:
the first adjusting device is used for adjusting the position and/or the angle of the first reflective mirror;
and/or, a second adjusting device, which adjusts the position and/or angle of the second reflector;
and/or, a third adjusting device for adjusting the position and/or angle of the triangular prism;
and/or a fourth adjusting device for adjusting the position and/or the angle of the monocular measuring unit.
Further, the optical path system further comprises a tripod connecting device; the tripod connecting device is an interface for connecting the optical path system with a tripod.
Further, the first mirror surface of the triangular prism is perpendicular to the second mirror surface of the triangular prism.
Further, the optical path system further includes:
and the strain processing equipment is used for realizing the sub-pixel displacement measurement algorithm.
The invention also provides a calibration method for calibrating the optical path system,
before the step S101, the method further comprises the following steps:
and adjusting the optical path system based on the three-dimensional characteristics of the tested sample, and calibrating the first virtual image and the second virtual image.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a flow chart of a monocular three-dimensional high-speed measurement method in accordance with an embodiment of the present invention;
FIG. 2 is an optical diagram of an optical path system according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a first reflective mirror and an adjustment platform in an optical path system according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a second reflective mirror and an adjustment platform in an optical path system according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a triangular prism and an adjustment platform in an optical path system according to an embodiment of the present invention;
wherein: 1. a first reflective mirror; 2. a second reflective mirror; 3. a triangular prism; 4. a first light source; 5. a second light source; 6. a monocular acquisition unit; 7. a tripod attachment; 8. a sample to be tested; 9. a first virtual image; 10. and a second virtual image.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It is noted that various aspects of the embodiments are described below within the scope of the appended claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the disclosure, one skilled in the art should appreciate that one aspect described herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number of the aspects set forth herein. Additionally, such an apparatus may be implemented and/or such a method may be practiced using other structure and/or functionality in addition to one or more of the aspects set forth herein.
It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than the number, shape and size of the components in practical implementation, and the type, quantity and proportion of the components in practical implementation can be changed freely, and the layout of the components can be more complicated.
In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects may be practiced without these specific details.
In an embodiment of the present invention, a monocular three-dimensional high-speed measurement method is provided, which is performed based on a first virtual image 9 and a second virtual image 10 of a sample 8 to be tested, which are acquired by a monocular measurement unit; the first virtual image 9 and the second virtual image 10 are used for observing the three-dimensional strain of the tested sample 8;
the measuring method comprises the following steps:
s101: identifying base pixel features of the first and second virtual images 9, 10;
s102: dividing and defining the basic pixel characteristics into a plurality of strain subareas;
s103: acquiring pixel characteristics in the first virtual image 9 and the second virtual image 10 during and/or after the strain process of the tested sample 8 to generate strain pixel characteristics;
s104: separating a plurality of regions to be calculated from at least one part of the strain subarea;
s105: extracting strain pixel characteristics of a region corresponding to each region to be calculated;
s106: comparing the extracted strain pixel characteristics of the area corresponding to each area to be calculated with the basic pixel characteristics to obtain the motion step length of each area to be calculated;
s107: based on each of the motion steps, a full field strain of the sample under test is calculated.
The outer surface of the sample 8 to be tested of the embodiment is provided with regularly arranged speckles; the base pixel features and the strain pixel features are both obtained based on the speckle.
In S107 of this embodiment, a sub-pixel displacement measurement algorithm is used to calculate the full-field strain of the measured sample.
As shown in fig. 1, the basic pixel feature of this embodiment is a three-dimensional speckle model obtained from a first virtual image 9 and a second virtual image 10 before the sample 8 to be tested is strained;
when the three-dimensional speckle model is divided and defined, setting the size of a sub-region based on the strain scale and the measurement precision of the tested sample 8;
when the full-field strain can be calculated only by measuring the strain concentration area, the area to be calculated is only obtained from the strain concentration area of the tested sample 8; when the strain concentration area can not meet the minimum limit enough to obtain the full-field strain, the area to be calculated needs to be obtained from a part of non-strain concentration area;
the motion step of this embodiment is the three-dimensional motion amount of the pixel;
referring to fig. 1, in one embodiment, a measurement method may set a calculation start point and a calculation end point; calculating a certain process of full-field strain in the strain process and after the strain process is between the starting point and the end point; in implementation, the strain pixel characteristics in the process are intercepted.
In one embodiment, the invention further provides an optical path system for implementing the monocular three-dimensional high-speed measurement method
Referring to fig. 2, the optical path system may include a first light source 4, a first reflective mirror 1: a second light source 5, a second reflector 2 and a triangular prism 3;
in practice, the first light source 4 and the second light source 5 may be disposed in front of the triangular prism 3 for emitting light to generate reflected light on the surface of the sample 8 to be tested.
It should be noted that the light source may be a light source commonly used in strain detection, and may also be a self-polishing light source, which is not limited herein.
The first mirror surface and the second mirror surface of the triangular prism 3 of the embodiment are vertical, and the included angle between the first mirror surface and the second mirror surface is over against the sample to be tested 8;
the first mirror 1 may be: and the first mirror surface is arranged on one side of the first light source 4 and used for reflecting the reflected light rays to the triangular prism 3.
The second reflective mirror 2 may be disposed at one side of the second light source 5 to reflect the reflected light to the second mirror surface of the triangular prism 3.
The triangular prism 3 may be disposed behind the first light source 4 and the second light source 5, and positioned at the first reflecting mirror 1: and the second reflecting mirror 2 so that the first mirror surface of the triangular prism 3 reflects the first reflecting mirror 1: the reflected light forms a first virtual image 9 corresponding to the sample 8 to be tested, and the second mirror surface of the triangular prism 3 forms a second virtual image 10 corresponding to the sample 8 to be tested by the light reflected by the second reflecting mirror 2.
A light is emitted toward the sample 8 to be tested by the light source, and the light is reflected by the surface of the sample 8 to be tested, and the first reflecting mirror 1: can reflect the reflection ray to in the first mirror surface of triangular prism 3, second reflector 2 reflects the reflection ray to in the second mirror surface of triangular prism 3 to form respectively by triangular prism 3 and tested the first virtual image 9 and the second virtual image 10 that the appearance 8 corresponds, accessible image acquisition equipment obtains the left side image and the right side image of being tested the appearance 8 according to this first virtual image 9 and second virtual image 10 at last.
Therefore, through the optical path system, imaging information corresponding to the tested sample 8 can be provided so as to be conveniently acquired by the image acquisition equipment to obtain a binocular image, for example, the image acquisition equipment can adopt monocular acquisition equipment, binocular acquisition equipment, multi-view acquisition equipment and the like, so that three-dimensional information processing can be carried out on the three-dimensional image processing equipment according to the binocular image, three-dimensional visual application to the tested sample 8 is realized, the structure in three-dimensional strain detection is simplified, and the problem of data loss caused by uneven brightness on the tested sample 8 can be avoided.
In some embodiments, the first mirror surface of the triangular prism 3 is perpendicular to the second mirror surface of the triangular prism 3, and the triangular prism 3 may be a triangular prism 3 with an isosceles triangle cross section, wherein the first mirror surface may be a mirror surface on one side of a right-angle side, and the second mirror surface may be a mirror surface on the other side of the right-angle side. In the present embodiment, the perpendicular bisector of the base of the isosceles triangle faces the sample 8; the first light source 4 and the second light source 5 are symmetrically arranged on the central vertical axis; the first mirror 1: and the second light emitting device is also arranged symmetrically with the middle vertical axis.
In some embodiments, the optical path system may further include: and the adjusting devices can adjust a plurality of devices (such as the first reflecting mirror 1, the second reflecting mirror 2, the triangular prism 3 and the like) in the optical path system, for example, the position, the angle, the height and the like of each device are adjusted, so that the incident light and/or the reflected light of the tested sample 8 are/is effectively transmitted in each device.
The embodiment of the present specification provides a first mirror 1 in an optical path system with reference to fig. 3: (e.g., left mirror) and an adjustable platform. As shown in the figure, a first adjustment device may be employed to adjust the first mirror 1: (e.g., the left mirror as identified in the figure) to better direct light emitted by the sample under test 8 into the triangular prism 3.
In an implementation, the first adjusting device may include a fixed bracket, a rotating platform, and an adjusting platform, and the adjusting platform may further include two buttons for XY axial adjustment. The reflector can be fixed in the fixed support, the fixed support can be installed in the rotating platform, and the rotating platform can be installed in the adjusting platform.
The X axial position of the left side reflector and the X axial position of the fixed support can be adjusted through the adjusting platform X to the adjusting button, the Y axial position of the left side reflector and the Y axial position of the fixed support can be adjusted through the adjusting platform Y to the adjusting button, and the angle of the left side reflector and the angle of the fixed support can be adjusted through adjusting the left side reflector rotating platform.
Referring to fig. 4, the embodiment of the present disclosure provides a schematic diagram of a second reflective mirror 2 (e.g., a right reflective mirror) and an adjustment platform in an optical path system. As shown in the figure, a second adjusting device may be used to adjust the position and/or angle of the second mirror 2 (the right mirror as identified in the figure) to better emit the light emitted by the sample under test 8 into the triangular prism 3.
In an implementation, the second adjusting device may include a fixed bracket, a rotating platform, and an adjusting platform, and the adjusting platform may further include two buttons for XY axial adjustment. The reflector can be fixed in the fixed support, the fixed support can be installed in the rotating platform, and the rotating platform can be installed in the adjusting platform.
The X axial position of the right side reflector and the X axial position of the fixed support can be adjusted through adjusting the platform X to the adjusting button, the Y axial position of the right side reflector and the Y axial position of the fixed support can be adjusted through adjusting the platform Y to the adjusting button, and the angle of the right side reflector and the angle of the fixed support can be adjusted through adjusting the right side reflector rotating platform.
Referring to fig. 5, an embodiment of the present disclosure provides a schematic diagram of a triangular prism 3 and an adjustment platform in an optical path system. As shown in the drawing, a third adjusting means may be employed to adjust the position and/or angle of the triangular prism 3 to better align the first reflective mirror 1: and the light reflected by the second reflecting mirror 2 can form a clear and accurate virtual image after passing through the mirror surface of the triangular prism 3.
In an implementation, the third adjusting device may include a fixed bracket, a rotating platform, and an adjusting platform, and the adjusting platform may further include two buttons for XY axial adjustment. The triangular prism 3 can be fixed in a fixed support, the fixed support can be arranged in a rotary platform, and the rotary platform can be arranged in an adjusting platform.
The X axial position of the triangular prism 3 and the fixed support can be adjusted through adjusting the X-direction adjusting button of the platform, the Y axial position of the triangular prism 3 and the fixed support can be adjusted through adjusting the Y-direction adjusting button of the platform, and the angle of the triangular prism 3 and the fixed support can be adjusted through adjusting the rotary platform of the triangular prism 3.
In some embodiments, the optical path system further comprises a tripod attachment 7; the tripod connecting device 7 is used for connecting the measuring system with an interface of a tripod.
In one embodiment, the measurement system further includes a monocular acquisition unit 6, which performs image acquisition on the virtual image provided in the foregoing embodiment to perform three-dimensional image acquisition on the sample 8 to obtain three-dimensional image data of the sample 8 in the strain detection.
In implementation, the monocular acquisition unit 6 may be configured to acquire the first virtual image 9 and the second virtual image 10 formed by the optical path system, so as to obtain left image information of the sample to be tested 8 by acquiring the first virtual image 9 and obtain right image information corresponding to the sample to be tested 8 by acquiring the second virtual image 10, that is, obtain binocular image data corresponding to the sample to be tested 8, and complete three-dimensional image acquisition corresponding to the sample to be tested 8.
The structure of the three-dimensional image acquisition system can be simplified through the optical path system and the monocular image acquisition equipment, and the three-dimensional strain measurement and detection device can be applied to the three-dimensional strain measurement and detection through the monocular image acquisition equipment. Moreover, after the monocular three-dimensional image acquisition system is matched with a monocular three-dimensional DIC algorithm, not only can the three-dimensional strain measurement be realized, but also the defect that the measurement data is lost due to uneven light field brightness in the traditional optical path system can be eliminated.
In some embodiments, the monocular capturing unit 6 may include a single lens and a single camera, wherein the single lens and the single camera are fixed in focal length and thus may be directly used for capturing images.
In some embodiments, in view of the conventional optical path system, for example, an optical path system using a binocular collecting device and a dual light source for illumination, for example, an optical path system using a monocular collecting device and a single light source, due to the light source, the collecting device and other devices, operations such as reinstallation, calibration and the like are required before each measurement and use, the use process is complicated, and the test time is long. Therefore, in the embodiment of the specification, spatial relationships such as mutual position distances and angles between the light reflecting devices (such as the reflective mirrors, the prisms and the like) and the light sources can be fixed, so that the light reflecting devices are well calibrated when leaving a factory, and the light reflecting devices can be directly used for measurement without being reinstalled and calibrated after leaving the factory, thereby simplifying the use requirements, and enabling the light path system to be fast and convenient in actual use and short in preparation time, so that the use efficiency is improved.
In one embodiment, the optical path system further includes a strain processing device for implementing S107 of the measurement method in the above embodiment, the strain processing device employs a high-precision and high-efficiency sub-pixel displacement measurement algorithm (IC-GN algorithm) whose principle is as follows:
The advanced IC-GN algorithm,which was recently introduced into DIC community by the authors of this paper[17],is employed for real-time and high-accuracy displacement/strain determination in the proposed video extensometer.Using the pre-estimated initial guess of displacements at each measurement point,IC-GN algorithm can determine subpixel displacements at these points by optimizing the following robust zero-mean normalized sum of squared difference(ZNSSD)criterion.
where f(x)and g(x)denote the grayscale levels at x＝(x,y,1)T of reference image and the deformed image,
are the mean intensity value of the two subsets,
and
ξ＝(Δx,Δy,1)T is the local coordinates of the pixel point in each subset.Since video extensometer is mainly used to determine the uniform tensile or compressive strains,the regular first-order shape function comprising six deformation parameters are used.Thus W(ξ；p)is the warp function with p＝(u,ux,uy,v,vx,vy)T,also known as displacement mapping function in DIC,depicting the position and shape of the target subset relative to the reference subset；W(ξ；Δp)withΔp＝(Δu,Δux,Δuy,Δv,Δvx,Δvy)T is the incremental warp function exerted on the reference subset.
in an embodiment, the present invention further provides a calibration method for calibrating the optical path system, including:
according to the first virtual image 9 and the second virtual image 10, adjusting at least one of the following optical path systems:
the light emission characteristics such as the wavelength, the illumination intensity, and the like of the first light source 4 and the second light source 5;
the position and/or angle of the first mirror 1;
the position and/or angle of the second mirror 2;
the position and/or angle of the triangular prism 3;
the position and/or angle of the monocular measuring unit;
finally, the three-dimensional characteristics which can meet the three-dimensional strain measurement process can be observed by the first virtual image 9 and the second virtual image 10 which are collected by the monocular measurement unit.
The above adjustments are made in accordance with the specific three-dimensional characteristics of the sample 8 being tested.
The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A monocular three-dimensional high-speed measurement method is characterized in that the method is carried out based on a first virtual image and a second virtual image of a sample to be measured, which are acquired by a monocular measurement unit; the first virtual image and the second virtual image are used for observing three-dimensional strain of the tested sample;
the measuring method comprises the following steps:
s101: identifying base pixel features of the first and second virtual images;
s102: dividing and defining the basic pixel characteristics into a plurality of strain subareas;
s103: acquiring pixel characteristics in the first virtual image and the second virtual image during and/or after the strain process of the tested sample to generate strain pixel characteristics;
s104: separating a plurality of regions to be calculated from at least one part of the strain subarea;
s105: extracting strain pixel characteristics of a region corresponding to each region to be calculated;
s106: comparing the extracted strain pixel characteristics of the area corresponding to each area to be calculated with the basic pixel characteristics to obtain the motion step length of each area to be calculated;
s107: based on each of the motion steps, a full field strain of the sample under test is calculated.
2. The measurement method according to claim 1, wherein the outer surface of the sample under test is provided with regularly arranged speckles; the base pixel features and the strain pixel features are both obtained based on the speckle.
3. The measurement method according to claim 1, wherein in S107, the calculation of the full-field strain of the test specimen employs a sub-pixel displacement measurement algorithm.
4. An optical path system for implementing the monocular three-dimensional high-speed measurement method according to any one of claims 1 to 3, comprising: the device comprises a first light source, a first reflector, a second light source, a second reflector and a triangular prism;
the triangular prism is arranged between the first reflective mirror and the second reflective mirror, and a sample to be tested is placed in front of the triangular prism;
the first light source is arranged on one side of the first reflector, which is far away from the triangular prism, and is used for emitting light rays to generate first reflected light rays on the surface of the sample to be tested;
the second light source is arranged on one side of the second reflector, which is far away from the triangular prism, and is used for emitting light rays to generate second reflected light rays on the surface of the sample to be tested;
the first reflector is used for reflecting the first reflected light to the first mirror surface of the triangular prism;
the second reflector is used for reflecting the second reflected light to the second mirror surface of the triangular prism;
the first mirror surface of triangular prism is used for with first reflection light forms the first virtual image that is tested the sample and corresponds, the second mirror surface of triangular prism is used for with second reflection light forms the second virtual image that is tested the sample and corresponds.
5. The optical path system according to claim 4, further comprising a monocular acquisition unit configured to acquire the first and second virtual images.
6. The optical path system according to claim 5, further comprising:
the first adjusting device is used for adjusting the position and/or the angle of the first reflective mirror;
and/or, a second adjusting device, which adjusts the position and/or angle of the second reflector;
and/or, a third adjusting device for adjusting the position and/or angle of the triangular prism;
and/or a fourth adjusting device for adjusting the position and/or the angle of the monocular measuring unit.
7. The optical circuit system of claim 4, further comprising a tripod attachment; the tripod connecting device is an interface for connecting the optical path system with a tripod.
8. The optical path system according to claim 4, wherein the first mirror surface of the triangular prism is perpendicular to the second mirror surface of the triangular prism.
9. The optical path system according to claim 4, further comprising:
and the strain processing equipment is used for realizing the sub-pixel displacement measurement algorithm.
10. A calibration method for calibrating the optical path system according to any one of claims 4 to 9, characterized in that:
before the step S101, the method further comprises the following steps:
and adjusting the optical path system based on the three-dimensional characteristics of the tested sample, and calibrating the first virtual image and the second virtual image.
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