可以demo的KNN分类器，对模式识别十分重要的作用，有着较好的分类效果，可以帮助新手更好的理解KNN原理，对人脸识别有着很好的演示作用。-Can demo KNN classifier, the pattern recognition is an important role, has a good classification effect, can help beginners a better understanding of KNN principle, has a very good