Stem Porosity Determination of Straws Using Conventional Laboratory Tests and Image Processing Methods

ABSTRACT

For sustainable thermal insulations, vegetable fibers/stems are widely used, which have very dispersed material properties even within a variety. The examination of the fibers’ porosity in the conventional way provided reference values in this study, but it can be problematic for cellulose-based fibers. This study examines the porosity of two straw types (barley and wheat) and searches for faster and easier tests; it reveals the inaccuracies that can occur in different methods. The image processing method is applied on records of intact cross-sections made by scanning electron microscope; the essential circumstances to reach the intact cross-section are also discussed in the paper. Stitched cross-sections, made from overlapping records using the same magnification, are supplemented by detailed images with higher magnification. On the fused/detailed images, the entire region of the cross-sections was segmented. Each pore was automatically analyzed (area, diameter, perimeter) to determine porosity; the result was compared to the conventional method. Comparing the entire and the detailed cross-sectional image gives information about the importance of magnification in the analysis. The presented method is suitable for porosity measurement but needs some modification in sample preparation and image capturing. Both the conventional and image processing methods provide the same results in ratios between the two straw types but different absolute values.

摘要

为了实现可持续的隔热, 植物纤维/茎被广泛使用, 其材料特性非常分散, 即使在各种材料中也是如此. 在本研究中, 用常规方法检查纤维的孔隙率提供了参考值, 但对于纤维素基纤维来说可能存在问题. 本研究考察了两种秸秆类型 (大麦和小麦) 的孔隙度, 并寻求更快更容易的测试; 它揭示了不同方法可能出现的不精确性. 图像处理方法应用于扫描电子显微镜制作的完整横截面记录; 文中还讨论了达到完整横截面的必要条件. 缝合的横截面由使用相同放大率的重叠记录制成, 由放大率更高的详细图像补充. 在融合/细节图像上, 对整个横截面区域进行分割. 自动分析每个孔隙 (面积, 直径, 周长) 以确定孔隙度; 将结果与传统方法进行了比较. 通过比较整个横截面图像和详细横截面图像, 可以了解放大率在分析中的重要性. 该方法适用于孔隙度测量, 但在样品制备和图像采集方面需要进行一些修改. 传统方法和图像处理方法在两种秸秆类型之间的比率方面提供相同的结果, 但绝对值不同.

KEYWORDS:

• Stem porosity
• organic insulation
• SEM
• scanning electron microscope
• image processing
• straw

关键词:

• 阀杆孔隙度
• 有机绝缘
• 扫描电子显微镜
• 图像处理
• 稻草

Disclosure statement

No potential conflict of interest was reported by the author(s).