实现用SDRAM运行nios，同时用SRAM保存摄像头数据，是学习PCA特征提取的很好的学习资料，实现了对10个数字音的识别。- Implemented with SDRAM run nios, while saving camera data SRAM, Is a good learning materials to learn PCA feature extraction, To achieve the recognition of 10 digital sound.