基于双CCD相机的三轴试验三维成像测量技术

提出了一种基于双CCD相机的三轴试验三维成像测量技术,在三轴试验仪前后面分别放置一台CCD相机,利用具有黑白方格的橡皮膜代替传统的橡皮膜.在试验过程中对试样进行图像采集,能够捕捉试样全表面的变形.提取和跟踪图像中黑白方格的角点并对试样的边界进行识别,基于三轴试样的水平截面在变形前后均保持水平圆形平面的假设,对前后表面分别采集到的图像进行拼接处理,初步实现了三轴试验过程中试样变形的三维测量,与有限元软件ANSYS相结合,能够绘制试样表面的三维变形云图,并将这种技术应用到了硅藻土的三轴试验研究中,取得了较好的测量效果.

3D Image Measurement of Triaxial Testing Using Two CCD Cameras

A three-dimensional digital image measurement technique by using two CCD cameras placed at the front and back of the triaxial testing machine， respectively， was proposed. A plastic membrane with white and black grids was used to replace the traditional plastic membrane. The images of the specimen obtained during the triaxial testing were able to capture the deformation of the whole specimen surface. By extracting and tracking the corner points of white and black grids， and detecting the edge of the specimen， the front and back images were stitched together and three-dimensional deformation measurement of the soil specimen was realized based on the assumption that the horizontal cross section of the soil specimen will keep horizontal circular plane before and after deformation. By combining with the numerical analysis with ANSYS finite element software， 3D surface strain contour can be obtained. This technique was applied to triaxial testing of diatomite and it achieved very good measurement effects.