Microscopic Image Classification of Inertinite of Coal Based on Wavelet Transform

On the basis of analyzing the characteristics of microscopic images of inertinite in coal, an automatic classification method for macerals in inertinite of coal based on wavelet transform was proposed. Firstly, the coal microscopic image was decomposed with discrete wavelet transform, features from coefficients corresponding to three directions (horizontal, vertical and diagonal) were designed, which were employed to characterize the texture feature. After comprehensively analyzing these features, energy deviation of horizontal, variance of diagonal, as well as brightness ratio of the image were selected to build a feature set. Then, a class of support vector machine (SVM) based classifiers were constructed, and 7 macerals of inertinite were classified. By comparing the results of the proposed method with those of others, it shows that the proposed method of feature selection and classifier has distinct advantage in classification accuracy.