资 源 简 介
SIFT算法由D.G.Lowe 1999年提出，2004年完善总结。后来Y.Ke将其描述子部分用PCA代替直方图的方式，对其进行改进。
2 SIFT 主要思想
SIFT算法是一种提取局部特征的算法，在尺度空间寻找极值点，提取位置，尺度，旋转不变量。
-a method for extracting distinctive invariant features from
images that can be used to perform reliable matching between different views of
an object or scene. The features are invariant to image scale and rotation, and
are shown to provide robust matching across a a substantial range of affine distortion,
change in 3D viewpoint, addition of noise, and change in illumination.
The features are highly distinctive, in the sense that a single feature can be correctly
matched with high probability against a large database of features from
many images.
