中文说明：应用程序主要使用特征提取方法提取的叶片，包括外接的圆、 七个不变矩等，几个几何特征和主成分分析，其尺寸减少，最后只 BP PNN 两个方法来分类，准确率达 90%以上。
English Description：
Application mainly use feature extraction to extract several geometric characteristics of blade, including circumscribed circle, seven invariant moment, etc., and principal component analysis, its dimension reduction, finally only BP, PNN two methods to classify, accuracy above 90%.