Automated analysis of CT images for the inspection of hardwood logs

Abstract

--This paper investigates several classifiers for labeling internal features of hardwood logs using computed tomography (CT) images.A primary motivation is to locate and classify internal defects s o that an optimal cutting strategy can be chosen. Previous work has relied on combinations of low-level processing, image segmentation, autoregressive texture modeling, and knowledge-based analysis. Most previous work has also been limited to two-dimensional analysis of a single species only. This paper describes these approaches briefly, and compares them with a feed-forward neural-net classifier that we have developed. In order to accommodate species with different cell anatomies, CT density values are first normalized.Features are then extracted, primarily using local three-dimensional data, Somewhat surprisingly, this Iocality approach has resulted in a pixel-by-pixel classification accuracy of 95%. This accuracy improves during subsequent morphological processing steps which refine the detected defect regions in the images.