Firstly, the watermarking data are coded and replaced according to BCH.And then, the coded data and synchronization codes are embedded into the candidate middle frequency coefficients in DCT domain.

• 该方法先将水印信号进行BCH编码并按密钥置换，然后将编码后的数据和同步码依次嵌入到DCT块的候选中频系数中，并通过同步码来实现水印的快速随机检测。