文章基本信息

标题：X-ray Micro-CT: How Soil Pore Space Description Can Be Altered by Image Processing
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作者：Sarah Smet ; Erwan Plougonven ; Angélique Leonard 等
期刊名称：Vadose Zone Journal
电子版ISSN：1539-1663
出版年度：2018
卷号：17
期号：1
页码：1-13
DOI：10.2136/vzj2016.06.0049
出版社：Soil Science Society of America, Inc.
摘要：A physically accurate conversion of the X-ray tomographic reconstructions of soil into pore networks requires a certain number of image processing steps. An important and much discussed issue in this field relates to segmentation, or distinguishing the pores from the solid, but pre- and post-segmentation noise reduction also affects the pore networks that are extracted. We used 15 two-dimensional simulated grayscale images to quantify the performance of three segmentation algorithms. These simulated images made ground-truth information available and a quantitative study feasible. The analyses were based on five performance indicators: misclassification error, non-region uniformity, and relative errors in porosity, conductance, and pore shape. Three levels of pre-segmentation noise reduction were tested, as well as two levels of post-segmentation noise reduction. Three segmentation methods were tested (two global and one local). For the local method, the threshold intervals were selected from two concepts: one based on the histogram shape and the other on the image visible-porosity value. The results indicate that pre-segmentation noise reduction significantly (p < 0.05) improves segmentation quality, but post-segmentation noise reduction is detrimental. The results also suggest that global and local methods perform in a similar way when noise reduction is applied. The local method, however, depends on the choice of threshold interval.
关键词：CT; computed tomography; GM; gradient masks; IK; indicator kriging; ME; misclassification error; NU; non-uniformity; PBA; porosity-based; RE_g; relative error in the pore shape; RE_K; relative error in conductance; RE_P; relative error in calculated porosity; RS; real soil; TH; threshold.