说明：  该代码为利用几何不变矩提取图像几何特征的代码，用matlab编写，提取7个Hu矩为特征向量。可以用于基于内容的图像检索
(The code for the image using the geometric moment invariant geometric features extracted code, written with matlab to extract seven Hu moments as features. Can be used for content-based image retrieval)