灰度共生矩阵建立在估计图像的一阶组合条件概率密度函数的基础上, 其通过计算图像中有一定距离和一定方向的两点之间灰度的相关性, 反映图像在方向、间隔、变化幅度及快慢上的综合信息。-The GLCMs are stored in a i x j x n matrix, where n is the number of GLCMs calculated usually due to the different orientation and displacements used in the algorithm. Usually the values i and j are equal to　NumLevels　parameter of the GLCM computing function graycomatrix(). Note that matlab quantization values belong to the set {1,..., NumLevels} and not　{0,...,(NumLevels-1)} as provided in some references