现有的应力波木材检测仪只能测定木材内部是否存在缺陷,无法对木材缺陷类型进行分类。笔者提出了一种结合应力波无损检测技术和支持向量机( SVM)的木材缺陷识别分类方法,该方法首先测量木材内部的应力波传播速度,以此作为分类特征,利用支持向量机对木材的内部缺陷进行分类。为了验证该方法的有效性,选取健康的以及含有不同缺陷的山核桃木试样31件、松木试样28件,采集山核桃木试样应力波传播速度数据117组、松木试样应力波传播速度数据80组,以应力波传播速度为分类特征,利用支持向量机对木材的缺陷类型进行分类。结果表明:山核桃木试样缺陷分类准确率达到93.75%,松木试样缺陷分类准确率达到95%。该方法不仅能识别木材内部是否存在缺陷,还能对木材的空洞、裂缝、腐朽等缺陷进行准确分类。
The existing stress wave testing can only determine the existence of defects in the wood, but can not classify the type of wood defect. This paper presents a method which combines stress wave nondestructive testing technology and support vector machine ( SVM) to identify and classify wood defects. This method measures stress wave velocity in the wood firstly, and then classifies the internal conditions of wood using SVM with the stress wave velocity as the classifica.tion feature. In order to demonstrate the effectiveness of the proposed method, 31 pecan wood samples and 28 pine wood samples with different conditions were selected as experimental samples. The Arbotom detector from Rinntech Company in German was used to collect 117 groups of data of stress wave velocity from pecan wood and 80 groups of data of stress wave velocity from pine wood. The classification accuracy of pecan wood and pine wood are 93.75% and 95% respective.ly. This detection method can not only recognize wood defect but also can accurately distinguish the defect type including voids, cracks, and decay.