把图像放置在Gaussian Scale Space，并求出各层图像的Hessian 矩阵。 通过Hessian举证，来求出图像中的blob和ridge。-The image is placed in the Gaussian Scale Space, and calculate the Hessian matrix of the layers of the image. At last the blob and ridge of the image will be detected.

考虑了放射变换因素，比sift有更好的效果，但是速度由于增加了旋转的考虑会变慢很多！-A fully affine invariant image comparison method, Affine-SIFT (ASIFT) is introduced. While SIFT is fully invariant with respect to only four parameters namely zoom, rotation and translation, the new method t

海森差分行列式值,可在匹配时设定一定的阈值，从而减少匹配时间。(Hessian difference determinant value can be set to a certain threshold in the matching, so as to reduce the matching time.)