ML法能够很好的估计信号的信噪比,实现了图像的加水印，去噪，加噪声等功能，预报误差法参数辨识-松弛的思想。- ML estimation method can be a good signal to noise ratio, Realize image watermarking, de-noising, plus noise and other functions, Prediction Error Method for Parameter Identification- the idea of