总变差滤波能保持边缘，4阶PDE滤波能在图像的光滑区域消除阶梯现象，为此提出了一个用于图像去噪的基于偏微分方程(PDE)的组合模型，把总变差(toval varition,TV)滤波和一个四阶PDE滤波通过某一权函数τ进行了加权组合。该组合模型很好地保留了二者的优点。数值试验结果表明，新模型在信噪比等方面比单纯的用一种滤波有较大的改进。

A combined model based PDE is proposed here ,which can be used in image denoising. It combines the Total Variation(TV) filter and a fourth order PDE filter by a weighting function τ. TV filter is able to preserve edges and the fourth order PDE filter can overcome the staircase effect in smooth regions. The combined model preserve the advantages of both. Numerical experiments show that the combined model has more improvement on signal noise ratio(SNR) than using only one filter.