中文摘要：

在水稻脱粒、储运、加工过程中,外界机械作用力是造成稻谷损伤破损的主要方式,造成的内部裂纹肉眼无法观察但影响稻谷的存储、加工以及种子的发芽率等。该文利用质构仪对稻谷进行挤压力学特性试验,分析稻谷损伤破碎过程;对受不同载荷的稻谷进行CT扫描试验,结合数字图像处理方法对稻谷进行损伤表征分析与三维重构,旨在提出一种新的稻谷内部损伤定量评价方法。结果表明：伪彩色图像处理可以提高CT图像的视觉分辨率;灰度值以及灰度直方图分析可以识别稻谷的胚、胚乳以及裂纹大小,并定量分析;对分割后的二值图像进行像素点统计分析得到80,100,120,140,160 N载荷下的损伤度分别为0,0.26%,0.39%,0.93%,1.79%;重构的三维模型可以看出裂纹一般沿着短轴方向扩展,随着载荷增大,原有裂纹逐渐变宽,并产生新的沿着长短轴的混合裂纹,直到糙米断裂。该研究可为谷物内部损伤定量表征分析提供新思路。

英文摘要：

In the process of rice harvesting, storage and transportation, external mechanical force is the main way to damage the rice. The internal cracks can not be observed by the naked eye, but affect the storage, processing and germination rate of rice. In this paper, the mechanical properties of rice were analyzed by using a texture analyzer, and the damage and fracture process of rice was analyzed. Because the brown rice was more brittle than the chaff, the brown rice first had cracks under the loading condition. As the load increased, the brown rice was broken and the chaff began to crack. After repeated tests, when the moisture content was 12.83% and the loading mode was extrusion along the thickness direction of rice, the destructive power of this kind of rice grain was 100 N. The CT（computed tomography） scan test was performed for the rice under different loads, and pseudo-color image processing, gray value and gray histogram analysis, and threshold segmentation of2-mode method and Feldkamp reconstruction algorithm（Feldkamp-Davis-Kress） were used to process the CT scan images.The research results showed that pseudo-color image processing could improve the visual resolution of CT images, and it was easy to observe the shape of cracks. Analysis of gray value and gray histogram could identify the organization of rice and cracks, and it showed that the gray value of cracks and connection of the embryo and endosperm was 0-15, and the maximum gray value of 35-42 corresponded to the embryo. It could be seen from the gray histogram that the majority of rice grains were endosperm, and the embryo and cracks and the joints occupied a small amount. The 2-mode method was used to segment the CT images and the median filter was used to eliminate the salt and pepper noise. Finally, the binary image was obtained. The gray value corresponding to the crack and the joint of the embryo and endosperm was 0, and the grey value of other tissues was 1. The crack area was obtained by subtracting the number of pixels at the joint b