The Poisson’s ratio for all specimens was analyzed by image processing with Image J program v2.0.0. The Material Testing System (LRX-PLUS, Lloyd instruments, West Sussex, UK) was utilized to test the specimens. A digital microscope (BX51, Olympus Corporation, Tokyo, Japan) was used to capture images in order to measure the displacement of the specimen (see Fig. 2).1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\varepsilon}_{\mathrm{x}}=\frac{\left|A-B\right|-\left|A0-B0\right|}{\left|A0-B0\right|} $$\end{document}εx=A−B−A0−B0A0−B0 2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\varepsilon}_{\mathrm{y}}=\frac{\left|C-D\right|-\left|C0-D0\right|}{\left|C0-D0\right|} $$\end{document}εy=C−D−C0−D0C0−D0 3\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \nu = \frac{\upvarepsilon \mathrm{x}}{\ \upvarepsilon \mathrm{y}} $$\end{document}ν=εxεywhere:εxstrain of x-axis.εystrain of y-axis.νmaterial Poisson’s ratio.A0~D0initial point (load = 0).A~Dmoved point under load. Fig. 2Points were tracked to estimate Poisson’s ratio of the specimen by image processing. (a). (b) to (c) is changing image when the specimen was compressed