Based on the Laplacian distribution model of DCT coefficients, we deduce a theoretical relationship between the scaling parameter in some typical watermarking algorithms and the degradation of watermarked images.

• 建立了分块DCT变换域密信信号嵌入深度与含密图象客观降质评估量之间的关系，得到了可以实现恒降质信息隐藏的嵌入深度估计公式。