根据协变矩阵和求最小特征值的方法求出三维点云数据的法向，根据OpenGL实现可视化,程序实用.-Noraml directions of 3D points can be obtained by calculating the smallest eigenvalue of covariance matrix, also, the method can be visualized by OpenGL, which is practical.

Use matlab intelligent predictive control algorithm, Calculate the maximum eigenvalue judgment matrix of AHP, Modern signal processing jobs when the graduate.