用于SIFT变化的关键点判断，定对比度和herrian矩阵，最后结果为关键点在DOG里的坐标！,Change for the SIFT key points to determine, set contrast and herrian matrix, the final results for the key points in the coordinates in the DOG!

Hessian interest point detector

仿射不变Harris, Laplacian, det(Hessian) and Ridge 特征点检测 参考文献：An affine invariant interest point detector , K.Mikolajczyk and C.Schmid, ECCV 02, pp.I:128-142.-Matlab code for detecting Affine spatial interest points. Includes Harris, Laplacian, det(Hess