说明：  基于matlab和小波的图像压缩实践文档，每一步操作都有完整代码和必要说明，并有运行效果图，便于初学者快速学习小波图像压缩
(Matlab and wavelet based image compression practice document, every step of the operation code and the necessary instructions are complete and have run effect picture, easy for beginners to learn fast wavelet image compression)