fisher分类器是实现降维的过程，将要分类的样本映射到一条线上，即将二维降到一维，通过在线上找到一个点，从而将样本分离开-fisher classifier is to achieve dimensionality reduction process will be classified samples are mapped into a line, coming down to a two-dimensional one-dimensional, through online to find a spot, which will be separated　the sample