说明：  基于DWT的彩色图像数字水印的matlab实现水印的嵌入与提取，并对其进行arnold置乱，能抵抗噪声，剪切，压缩攻击
(Based on DWT color image digital watermark matlab watermarking embedding and extracting, and carries on the Arnold scrambling, can resist noise, shear and compression attack )