像的许多个空间中的一个。不管子空间的具体形式如何，这种方法用于图像识别的基本思想

都是一样的，首先选择一个合适的子空间，图像将被投影到这个子空间上，然后利用对图像

的这种投影间的某种度量来确定图像间的相似度，最常见的就是各种距离度量。-Like much of a space. Regardless of the specific sub-space form, this method has been applied to image recognition are the same basic idea, first of all, select an appropriate sub-space, image will be projected onto this subspace, and then use the image projection of this inter- some measure to determine similarity between images, the most common is that all kinds of distance measure.