基于阈值分割法的地下工程防水板孔隙结构识别

Identification of Pore Structure of Waterproof Board in Underground Engineering Based on Thresholding Method

利用X射线CT技术扫描地下工程高密度聚乙烯(HDPE)防水板,基于阈值分割法对获得图像进行分割处理,探讨该种分割方法在图像处理中的适用性。对经过处理的防水板试样置于显微CT设备上进行扫描,获得系列二维切片图像,利用阈值分割法对其中单张图像进行处理,得到较为理想的二值图像,对图像中孔隙进行标记,据此进行孔隙结构分析。结果表明:处理后图像中的大小孔隙可以被清晰识别;孔隙面积、孔隙率及孔隙连通性等指标整体水平较低;小孔隙个数最多,且小孔隙在孔隙总面积中占有很大比例,孔隙面积与其个数与直径有关。研究结果证实利用阈值分割法对显微CT扫描图像进行分割处理是可行的,为地下工程防水板材料微观研究提供方法上的参考。

High Density Polyethylene( HDPE) waterproof board employed in underground engineering is scanned by X-ray computed tomography and the gained images are segmented and processed based on thresholding method. This paper focuses on the applicability of the segmentation method during image processing. After the processed waterproof board sample is scanned by micro-CT,a series of twodimensional slice images are obtained. Single image is processed based on thresholding method to gain ideal binary images,and the pores in the image are marked to analyze the pore structure. The results show that both big and small pores in the processed image can be identified clearly; the overall level of the indexes such as pore area,porosity and pore connectivity is low; the number of small pores is big,small pores account for a large proportion in the total pore area and the pore area is related to the number and diameter of the pores. Research results confirm that it is feasible to segment and process micro-CT scanned images with thresholding method,which may provide a reference for microcosmic study on waterproof board in underground engineering.