However, the bases learned via NMF are not orthogonal.Translating an image into a vector often loses the structure information of pixels and leads to a high dimensionality.

• 然而传统算法中，NMF提取的特征是非正交的，且二维图像常被向量化处理，不仅丢失一些结构信息，还导致了数据的高维，不利于提高识别精度和速度。