CN111964600A - High-precision dual-axis optical extensometer and measurement method based on bidirectional field separation - Google Patents
High-precision dual-axis optical extensometer and measurement method based on bidirectional field separation Download PDFInfo
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Abstract
本发明公开了光学引伸计技术领域的一种基于双向视场分离的高精度双轴光学引伸计及测量方法，旨在解决现有技术中受测试时试样离面位移的影响，光学引伸计的应变测量精度不高的技术问题。远心镜头安装在数字相机上；四棱锥的每个侧面对应设置一个等边直角棱镜，其中两个等边直角棱镜沿水平向布置，另两个等边直角棱镜沿竖直向布置；被测样品表面的每个标距点上的漫射光场被四个等边直角棱镜分别反射至四棱锥的四个侧面上，再被四棱锥的侧面分别反射后以平行于所述远心镜头的光轴的方向进入远心镜头中；远心镜头对被测样品表面的每个标距点进行成像，数字相机拍摄将图像传输至数据处理装置；数据处理装置获取被测样品表面的局部均匀双向应变信息。
The invention discloses a high-precision biaxial optical extensometer and a measurement method based on the separation of two-way fields of view in the technical field of optical extensometers, aiming at solving the influence of the off-plane displacement of the sample during testing in the prior art. The technical problem of low accuracy of strain measurement. The telecentric lens is installed on the digital camera; an equilateral right-angle prism is correspondingly arranged on each side of the quadrangular pyramid, two equilateral right-angle prisms are arranged in the horizontal direction, and the other two equilateral right-angle prisms are arranged in the vertical direction; the measured The diffuse light field on each gauge point on the sample surface is reflected by four equilateral right-angle prisms to the four sides of the quadrangular pyramid, and then reflected by the sides of the quadrangular pyramid to form the light parallel to the telecentric lens. The direction of the axis enters the telecentric lens; the telecentric lens images each gauge point on the surface of the tested sample, and the digital camera shoots and transmits the image to the data processing device; the data processing device obtains the local uniform bidirectional strain on the surface of the tested sample information.
Description
技术领域technical field
本发明属于光学引伸计技术领域，具体涉及一种基于双向视场分离的高精度双轴光学引伸计及测量方法。The invention belongs to the technical field of optical extensometers, and in particular relates to a high-precision dual-axis optical extensometer based on bidirectional visual field separation and a measurement method.
背景技术Background technique
弹性模量和泊松比是材料的两个基本弹性常数，在结构设计与仿真中扮演着十分重要的作用，为了得到这两个参数，必须对材料的横向应变与轴向应变进行准确的测量。当前最常见的双向应变测试手段是粘贴直角应变花和采用双轴电子引伸计，这些方法在测量时需要在被测试样上安装元器件，容易给试样造成损伤，使得这些方法不适用小尺寸、大变形尤其是柔性材料的检测。光学应变测试方法主要以光学（视频）引伸计为代表。然而，受测试时试样离面位移的影响，以及相机分辨率的限制，当前光学引伸计的应变测量精度常常不高。Elastic modulus and Poisson's ratio are two basic elastic constants of materials, which play a very important role in structural design and simulation. In order to obtain these two parameters, it is necessary to accurately measure the transverse strain and axial strain of the material. At present, the most common two-way strain testing methods are pasting right-angle strain rosettes and using biaxial electronic extensometers. These methods need to install components on the test sample during measurement, which is easy to cause damage to the sample, making these methods unsuitable for small size , Large deformation, especially the detection of flexible materials. Optical strain testing methods are mainly represented by optical (video) extensometers. However, due to the out-of-plane displacement of the specimen during testing and the limitation of camera resolution, the strain measurement accuracy of current optical extensometers is often not high.
发明内容SUMMARY OF THE INVENTION
本发明的目的在于提供一种基于双向视场分离的高精度双轴光学引伸计及测量方法，以解决现有技术中受测试时试样离面位移的影响，光学引伸计的应变测量精度不高的技术问题。The purpose of the present invention is to provide a high-precision dual-axis optical extensometer and measurement method based on the separation of two-way fields of view, so as to solve the influence of the out-of-plane displacement of the sample during testing in the prior art, and the strain measurement accuracy of the optical extensometer is not high. high technical issues.
为达到上述目的，本发明所采用的技术方案是：一种基于双向视场分离的高精度双轴光学引伸计，包括：数据处理装置、数字相机、远心镜头、四棱锥和四个等边直角棱镜；所述远心镜头安装在所述数字相机上；所述四棱锥的每个侧面对应设置一个所述等边直角棱镜，其中两个所述等边直角棱镜沿水平方向布置，另两个所述等边直角棱镜沿竖直方向布置，每个所述等边直角棱镜与所述四棱锥的距离相等，所述四棱锥的底面与所述远心镜头的光轴垂直；被测样品表面的每个标距点上的漫射光场被四个所述等边直角棱镜分别反射至所述四棱锥的四个侧面上，再被所述四棱锥的侧面分别反射后以平行于所述远心镜头的光轴的方向进入所述远心镜头中；所述远心镜头根据接收到的光线，对被测样品表面的每个标距点进行成像，并在所述数字相机靶面上形成数字图像；所述数字相机拍摄所述数字图像并将所述数字图像传输至所述数据处理装置；所述数据处理装置包括相关运算模块和后处理模块，相关运算模块根据接收到的数字图像获取指定标距点沿着测量方向的位移信息；后处理模块利用相关运算模块获取的位移信息，结合指定标距点的间距信息获得被测样品表面的局部均匀应变信息。In order to achieve the above object, the technical scheme adopted in the present invention is: a high-precision dual-axis optical extensometer based on bidirectional field separation, comprising: a data processing device, a digital camera, a telecentric lens, a quadrangular pyramid and four equilateral sides A right-angle prism; the telecentric lens is mounted on the digital camera; each side of the quadrangular pyramid is correspondingly provided with an equilateral right-angle prism, wherein two equilateral right-angle prisms are arranged in the horizontal direction, and the other two are arranged in the horizontal direction. The equilateral right-angle prisms are arranged in the vertical direction, the distance between each equilateral right-angle prism and the quadrangular pyramid is equal, and the bottom surface of the quadrangular pyramid is perpendicular to the optical axis of the telecentric lens; the sample to be tested The diffused light field on each gauge point of the surface is reflected by the four equilateral right-angle prisms respectively to the four sides of the quadrangular pyramid, and then reflected by the sides of the quadrangular pyramid to be parallel to the quadrangular pyramid. The direction of the optical axis of the telecentric lens enters the telecentric lens; the telecentric lens images each gauge point on the surface of the sample to be measured according to the received light, and displays the image on the target surface of the digital camera. forming a digital image; the digital camera captures the digital image and transmits the digital image to the data processing device; the data processing device includes a correlation operation module and a post-processing module, and the correlation operation module is based on the received digital image Obtain the displacement information of the specified gauge point along the measurement direction; the post-processing module uses the displacement information obtained by the correlation operation module and combines the distance information of the specified gauge point to obtain the local uniform strain information on the surface of the measured sample.
进一步地，所述四棱锥和四个所述等边直角棱镜固定在一块固定板上，所述固定板安装在所述远心镜头上。Further, the quadrangular pyramid and the four equilateral right-angle prisms are fixed on a fixing plate, and the fixing plate is installed on the telecentric lens.
进一步地，所述四棱锥的每组相对侧面均互相垂直。Further, each set of opposite sides of the quadrangular pyramid are perpendicular to each other.
进一步地，所述远心镜头为物方远心或双侧远心镜头。Further, the telecentric lens is an object-side telecentric lens or a bilateral telecentric lens.
进一步地，所述数字相机安装在可调支架上。Further, the digital camera is mounted on an adjustable bracket.
进一步地，被测样品表面的水平方向均匀应变大小为(x2-x1)/sH，x1和x2分别为第一和第二标距点沿着水平方向的位移，sH为第一和第二标距点的初始间距，竖直方向均匀应变大小为(y2-y1)/sV，y1和y2分别为第三和第四标距点沿着竖直方向的位移，sV为第三和第四标距点的初始间距。Further, the uniform strain size in the horizontal direction of the surface of the tested sample is (x 2 -x 1 )/s H , x 1 and x 2 are the displacements of the first and second gauge points along the horizontal direction, respectively, and s H is The initial distance between the first and second gauge points, the uniform strain in the vertical direction is (y 2 -y 1 )/s V , where y 1 and y 2 are the third and fourth gauge points along the vertical direction, respectively The displacement of s V is the initial spacing of the third and fourth gauge points.
一种基于双向视场分离的高精度双轴光学引伸计的应变测量方法，包括：A strain measurement method based on a high-precision dual-axis optical extensometer based on bidirectional field separation, comprising:
在被测样品的水平方向和竖直方向各选取两个标距点，将安装了远心镜头的数字相机安装在可调支架上，同时安装并调整四棱锥和四个等边直角棱镜，使选取的各标距点的上的漫射光场依次经过等边直角棱镜和四棱锥反射后进入远心镜头中；Select two gauge points in the horizontal and vertical directions of the sample to be tested, install the digital camera with the telecentric lens on the adjustable bracket, and install and adjust the quadrangular pyramid and four equilateral right-angle prisms at the same time, so that the The diffused light field on each selected gauge point is reflected by an equilateral right-angle prism and a quadrangular pyramid in turn and then enters the telecentric lens;
远心镜头根据接收到的光线在数字相机靶面上成像；数字相机将靶面上所成像转成数字图像，并将数字图像传输至数据处理装置；The telecentric lens forms an image on the target surface of the digital camera according to the received light; the digital camera converts the image on the target surface into a digital image, and transmits the digital image to the data processing device;
数据处理装置根据接收到的数字图像获取指定标距点沿着测量方向的位移信息，结合指定标距点的间距信息，获得被测样品表面的局部均匀双向应变信息。The data processing device obtains the displacement information of the specified gauge point along the measurement direction according to the received digital image, and obtains the local uniform bidirectional strain information on the surface of the measured sample in combination with the spacing information of the specified gauge point.
与现有技术相比，本发明所达到的有益效果：Compared with the prior art, the beneficial effects achieved by the present invention:
（1）本发明中采用一个四棱锥镜与四个直角棱镜的布置可以将上、下和左、右四个距离较远的标距点，经过光路反射汇聚到远心镜头中，使水平与竖直方向标距点间的距离即标距得到数倍的放大，因而极大提升了双向应变的测量精度；(1) In the present invention, the arrangement of one quadrangular prism and four right-angle prisms can make the upper, lower, left, and right gauge distance points with far distances converge into the telecentric lens through the reflection of the optical path, so that the horizontal and The distance between the gauge points in the vertical direction, that is, the gauge length, is amplified several times, thus greatly improving the measurement accuracy of the bidirectional strain;
（2）受离面位移影响小：由于远心镜头具有景深范围内放大倍率恒定的特性，使得标距点的微小离面位移并不会在数字相机的像面上产生虚假位移和虚假应变；(2) Less affected by off-plane displacement: Since the telecentric lens has the characteristic of constant magnification within the depth of field, the small off-plane displacement of the gauge point will not produce false displacement and false strain on the image plane of the digital camera;
（3）集成度高，便于组装：本发明中采用一个四棱锥镜和四个直角棱镜的光学布置简化了双向视场分离的实现步骤，且易集成为单个装置，直接与镜头连接，免去调节步骤。(3) High integration and easy assembly: the optical arrangement of one quadrangular prism and four right-angle prisms in the present invention simplifies the realization steps of bidirectional field separation, and is easy to integrate into a single device, which is directly connected to the lens, eliminating the need for Adjustment steps.
附图说明Description of drawings
图1是本发明实施例提供的一种基于双向视场分离的高精度双轴光学引伸计中的四棱锥的示意图；1 is a schematic diagram of a quadrangular pyramid in a high-precision dual-axis optical extensometer based on bidirectional field separation provided by an embodiment of the present invention;
图2是本发明实施例提供的一种基于双向视场分离的高精度双轴光学引伸计的光学原理示意图；2 is a schematic diagram of the optical principle of a high-precision dual-axis optical extensometer based on bidirectional field separation provided by an embodiment of the present invention;
图3是本发明实施例提供的一种基于双向视场分离的高精度双轴光学引伸计消除离面位移原理示意图。3 is a schematic diagram of the principle of eliminating out-of-plane displacement with a high-precision dual-axis optical extensometer based on bidirectional field separation provided by an embodiment of the present invention.
具体实施方式Detailed ways
下面结合附图对本发明作进一步描述。以下实施例仅用于更加清楚地说明本发明的技术方案，而不能以此来限制本发明的保护范围。The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to illustrate the technical solutions of the present invention more clearly, and cannot be used to limit the protection scope of the present invention.
需要说明的是，在本发明的描述中，术语“前”、“后”、“左”、“右”、“上”、“下”、“内”、“外”等指示的方位或位置关系为基于附图中所示的方位或位置关系，仅是为了便于描述本发明而不是要求本发明必须以特定的方位构造和操作，因此不能理解为对本发明的限制。本发明描述中使用的术语“前”、“后”、“左”、“右”、“上”、“下”指的是附图中的方向，术语“内”、“外”分别指的是朝向或远离特定部件几何中心的方向。It should be noted that, in the description of the present invention, the terms "front", "rear", "left", "right", "upper", "lower", "inner", "outer" and the like indicate the orientation or position The relationship is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. The terms "front", "rear", "left", "right", "upper" and "lower" used in the description of the present invention refer to the directions in the drawings, and the terms "inner" and "outer" respectively refer to is the direction toward or away from the geometric center of a particular part.
实施例一：Example 1:
如图1、图2所示，一种基于双向视场分离的高精度双轴光学引伸计，包括：数据处理装置、数字相机3、远心镜头4、起光线汇聚作用的四棱锥6和分别对应于被测样品1上的左、右、上、下四个标距点2的等边直角棱镜7~10；远心镜头4安装在数字相机3上，数字相机3通过可调支架5进行固定，本实施例中，可调支架5采用可调三脚架；四棱锥6的每个侧面对应设置一个等边直角棱镜，其中两个等边直角棱镜7、8沿水平方向布置，另两个等边直角棱镜9、10沿竖直方向布置，每个等边直角棱镜与四棱锥6的距离相等，四棱锥6的底面与远心镜头4的光轴垂直；被测样品1表面的每个标距点2上的漫射光场被四个等边直角棱镜分别反射至四棱锥6的四个侧面上，再被四棱锥6的侧面分别反射后以平行于远心镜头4的光轴的方向进入远心镜头4中；远心镜头4根据接收到的光线，对被测样品1表面的每个标距点2进行成像，并在数字相机3靶面上形成数字图像；数字相机3拍摄数字图像并将数字图像传输至数据处理装置；数据处理装置包括相关运算模块和后处理模块，相关运算模块根据接收到的数字图像获取指定标距点2沿着测量方向的位移信息；后处理模块利用相关运算模块获取的位移信息，结合指定标距点2的间距信息获得被测样品1表面的局部均匀应变信息。As shown in Figures 1 and 2, a high-precision dual-axis optical extensometer based on bidirectional field separation includes: a data processing device, a digital camera 3, a telecentric lens 4, a quadrangular pyramid 6 for light converging, and a separate Equilateral right angle prisms 7 to 10 corresponding to the left, right, upper and lower gauge length points 2 on the sample 1 to be tested; the telecentric lens 4 is mounted on the digital camera 3, and the digital camera 3 is carried Fixed, in this embodiment, the adjustable bracket 5 adopts an adjustable tripod; each side of the quadrangular pyramid 6 is correspondingly provided with an equilateral right angle prism, wherein the two equilateral right angle prisms 7 and 8 are arranged in the horizontal direction, and the other two are arranged in the horizontal direction. The right-
本实施例中，首先在被测样品1上选取光学引伸计的四个标距点2，左、右两个标距点2构成水平向引伸计，上、下两个标距点2构成竖直向引伸计，四个等边直角棱镜7~10与四棱锥6放置于相同的平面内，每个等边直角棱镜的斜面为镀膜反射面，且与四棱锥6的一个侧面平行，每个等边直角棱镜的斜面与被测样品1的表面都成45度；四棱锥6放置于远心镜头4正前方，其四个侧面均为镀膜反射面，且四棱锥6的每组相对侧面均互相垂直，四棱锥6位于四个等边直角棱镜7~10的中间位置，保证四个等边直角棱镜7~10的斜面与四棱锥6的四个侧面分别平行：等边直角棱镜7的斜面和四棱锥6的左侧面将第一个（左）标距点2发出的光线平移一个水平距离入射到远心镜头4，等边直角棱镜8的斜面和四棱锥6的右侧面将第二个（右）标距点2发出的光线也平移一个相同的水平距离入射到远心镜头4，等边直角棱镜9的斜面和四棱锥6的上侧面将第三个（上）标距点2发出的光线平移一个竖直距离入射到远心镜头4，等边直角棱镜10的斜面和四棱锥6的下侧面将第四个（下）标距点2发出的光线平移一个竖直距离入射到远心镜头4；一个远心镜头4和一台数字相机3安装在可调三角支架上，远心镜头4用来对被测样品1表面的四个标距点2成像，本实施例中，远心镜头4为物方远心或双侧远心镜头，利用远心镜头4放大倍率恒定的特性，消除被测样品1受离面位移带来的测量误差。一台数字相机3用来对被测样品1表面四个标距点2进行同时成像，并形成数字图像，四个标距点2分别位于数字相机3图像芯片的左、右、上、下区域，即拍摄到的数字图像中四个标距点2各占据1/4的视场，以实现对左、右、上、下四个目标区域图像的同时采集。可承载数字相机的三角架，保证能够稳固地承载数字相机3，使数字相机3的位置在一定范围内可调。数据处理装置包括相关运算模块和后处理模块。相关运算模块用来对数字相机采集到的数字图像进行相关运算，获取四个标距点2的位移信息；后处理模块利用相关运算模块获取的位移信息，结合四个标距点2的间距信息进行计算，获得被测样品1表面的双向应变信息。In this embodiment, firstly, four gauge length points 2 of the optical extensometer are selected on the sample 1 to be tested. The left and right gauge length points 2 form a horizontal extensometer, and the upper and lower gauge length points 2 form a vertical extensometer. For the straight extensometer, four equilateral right-angle prisms 7-10 are placed in the same plane as the quadrangular pyramid 6, and the inclined surface of each equilateral right-angle prism is a coating reflecting surface, and is parallel to one side of the quadrangular pyramid 6. Each The slope of the equilateral right-angle prism is 45 degrees from the surface of the tested sample 1; the quadrangular pyramid 6 is placed directly in front of the telecentric lens 4, and its four sides are coated reflection surfaces, and each group of opposite sides of the quadrangular pyramid 6 is They are perpendicular to each other, and the quadrangular pyramid 6 is located in the middle of the four equilateral right-angle prisms 7 to 10, ensuring that the slopes of the four equilateral right-angle prisms 7 to 10 are parallel to the four sides of the quadrangular pyramid 6: the slope of the equilateral right-angle prism 7 And the left side of the quadrangular pyramid 6 translates the light emitted by the first (left) gauge point 2 by a horizontal distance and is incident on the telecentric lens 4, and the bevel of the equilateral right angle prism 8 and the right side of the quadrangular pyramid 6 translate the first The rays from the two (right) gauge points 2 are also translated by the same horizontal distance and incident on the telecentric lens 4. The bevel of the equilateral right-angle prism 9 and the upper side of the quadrangular pyramid 6 connect the third (upper) gauge point The light emitted by 2 is shifted by a vertical distance and incident on the telecentric lens 4. The slope of the equilateral right-
被测样品表面的水平方向均匀应变大小为(x2-x1)/sH，x1和x2分别为第一和第二标距点沿着水平方向的位移，sH为第一和第二标距点的初始间距，竖直方向均匀应变大小为(y2-y1)/sV，y1和y2分别为第三和第四标距点沿着竖直方向的位移，sV为第三和第四标距点的初始间距。The magnitude of the uniform strain in the horizontal direction of the sample surface to be measured is (x 2 -x 1 )/s H , where x 1 and x 2 are the displacements of the first and second gauge points along the horizontal direction, respectively, and s H is the first and second gauge points. The initial spacing of the second gauge point, the uniform strain in the vertical direction is (y 2 -y 1 )/s V , y 1 and y 2 are the displacements of the third and fourth gauge points along the vertical direction, respectively, s V is the initial spacing of the third and fourth gauge points.
本实施例所述基于双向视场分离的高精度双轴光学引伸计，能够消除由被测样品离面位移而引起的虚假位移和虚假应变，虚假位移和应变产生原理如图3所示。普通相机镜头的成像遵循针孔成像模型，如图3中如果将标距点设定为被测样品表面上远离光轴的一点A，经过镜头会在像面上的a点成像。当离面位移使样品A点移动到了B点，由针孔模型可知将会在像面上b点成像。在被测样品无变形的条件下，仅由被测样品离面位移就使标距点产生了像面上的图像位移，位移的大小为a点和b点间的距离，根据位移数据可得出应变数据，即为虚假应变。由于远心镜头以平行视角观察物体，在景深范围内放大倍率恒定，若用远心镜头替换掉普通镜头，当点A移动到点B后，在像面上所成像点的位置不变，表明离面位移并不会导致虚假位移和虚假应变，因此，能够提高光学引伸计的变形测量精度。The high-precision dual-axis optical extensometer based on bidirectional field separation described in this embodiment can eliminate the false displacement and false strain caused by the out-of-plane displacement of the measured sample. The principle of false displacement and strain generation is shown in Figure 3. The imaging of a common camera lens follows the pinhole imaging model. As shown in Figure 3, if the gauge point is set to a point A on the surface of the tested sample that is far from the optical axis, the lens will image point a on the image surface. When the off-plane displacement moves the sample from point A to point B, it can be known from the pinhole model that the image will be imaged at point b on the image plane. Under the condition that the measured sample is not deformed, only the displacement of the measured sample from the surface will cause the image displacement of the gauge point on the image plane. The magnitude of the displacement is the distance between point a and point b. According to the displacement data, we can get If the strain data is output, it is a false strain. Since the telecentric lens observes the object from a parallel angle of view, and the magnification is constant within the depth of field, if the ordinary lens is replaced by the telecentric lens, when the point A moves to the point B, the position of the imaged point on the image plane remains unchanged, indicating that The out-of-plane displacement does not cause spurious displacement and spurious strain, therefore, the deformation measurement accuracy of the optical extensometer can be improved.
本发明使用棱镜组分离视场和远心镜头对被测样品表面的四个标距点进行成像，与传统的单相机相比，四个直角棱镜之间的相对位置，也是左、右两个标距点的间距和上、下两个标距点的间距，即标距根据实际需求可调，具有很高的灵活性。水平或竖直向的两标距点距离与应变测量精度紧密联系，增大两标距点间距可以扩大标距，在相对位移精度不变的情况下，也可有效提高应变测量的精度和分辨率，从而实现高精度的双向应变测量。The invention uses the prism group to separate the field of view and the telecentric lens to image the four gauge points on the surface of the tested sample. Compared with the traditional single camera, the relative positions between the four right-angle prisms are also the left and the right two. The distance between the gauge points and the distance between the upper and lower gauge points, that is, the gauge length can be adjusted according to actual needs, with high flexibility. The distance between the two gauge points in the horizontal or vertical direction is closely related to the strain measurement accuracy. Increasing the distance between the two gauge points can expand the gauge length. When the relative displacement accuracy remains unchanged, it can also effectively improve the accuracy and resolution of strain measurement. rate, so as to achieve high-precision bidirectional strain measurement.
实施例二：Embodiment 2:
本实施例与实施例一的区别在于，四棱锥6和四个等边直角棱镜7~10固定在一块固定板11上，固定板11安装在远心镜头4上。本实施例的光学布置简化了双向视场分离的实现步骤，且易集成为单个装置，直接与远心镜头连接，免去调节步骤，集成度高，便于组装。The difference between this embodiment and the first embodiment is that the quadrangular pyramid 6 and the four equilateral right-angle prisms 7 to 10 are fixed on a fixed plate 11 , and the fixed plate 11 is installed on the telecentric lens 4 . The optical arrangement of this embodiment simplifies the realization steps of bidirectional field of view separation, and can be easily integrated into a single device, which is directly connected to the telecentric lens, eliminating the need for adjustment steps, high integration, and easy assembly.
实施例三：Embodiment three:
基于实施例一和实施例二所述的基于双向视场分离的高精度双轴光学引伸计，本实施例提供一种基于双向视场分离的高精度双轴光学引伸计的测量方法，包括：Based on the high-precision dual-axis optical extensometer based on two-way separation of fields of view described in Embodiments 1 and 2, this embodiment provides a measurement method for a high-precision dual-axis optical extensometer based on separation of two-way fields of view, including:
在被测样品的水平方向和竖直方向各选取两个标距点，将安装了远心镜头的数字相机安装在可调支架上，同时安装并调整四棱锥和四个等边直角棱镜，使选取的各标距点的上的漫射光场依次经过等边直角棱镜和四棱锥反射后进入远心镜头中；Select two gauge points in the horizontal and vertical directions of the sample to be tested, install the digital camera with the telecentric lens on the adjustable bracket, and install and adjust the quadrangular pyramid and four equilateral right-angle prisms at the same time, so that the The diffused light field on each selected gauge point is reflected by an equilateral right-angle prism and a quadrangular pyramid in turn and then enters the telecentric lens;
远心镜头根据接收到的光线在数字相机靶面上成像；数字相机将靶面上所成像转成数字图像，并将数字图像传输至数据处理装置；The telecentric lens forms an image on the target surface of the digital camera according to the received light; the digital camera converts the image on the target surface into a digital image, and transmits the digital image to the data processing device;
数据处理装置根据接收到的数字图像获取指定标距点沿着测量方向的位移信息，结合指定标距点的间距信息，获得被测样品表面的局部均匀双向应变信息。The data processing device obtains the displacement information of the specified gauge point along the measurement direction according to the received digital image, and obtains the local uniform bidirectional strain information on the surface of the measured sample in combination with the spacing information of the specified gauge point.
以上所述仅是本发明的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明技术原理的前提下，还可以做出若干改进和变形，这些改进和变形也应视为本发明的保护范围。The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the technical principle of the present invention, several improvements and modifications can also be made. These improvements and modifications It should also be regarded as the protection scope of the present invention.
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