中文说明： NEC数字水印算法的实现，用matlab编写，里边还有详细介绍数字水印的知识，详细描述数字水印的插入以及提取过程。
English Description：
NEC digital watermarking algorithm, written in MATLAB, there is a detailed introduction to the knowledge of digital watermarking, a detailed description of the digital watermark insertion and extraction process.