针对未知脉冲噪声强度的退化图像的去噪,提出了一种新的自适应中值滤波算法,该算法主要基于以下两点：（1）根据模糊数学里的模糊度理论及随机脉冲噪声本身的去噪特点,提出了模糊指标的概念,并通过反向二阶拟合来获得噪声的强度信息;（2）引入了反映图像边缘信息的Prewitt梯度算子,并通过实验来得到合适的梯度阚值,以更好地保持图像的边缘等细节信息.通过将该算法与传统的中值滤波、基于排序阈值的开关中值滤波以及Sorin Zoican提出的改进的中值滤波进行的对比实验表明,该算法对噪声的强度有很好的估计,不仅提高了噪声去除的自适应性,尤其对含噪声多的图像的处理效果更为理想.

An improved adaptive median-based filter,based on extremum median filter,is proposed to restore images corrupted by salt and pepper noise,especially for those with unknown noise ratio.There are mainly two improved points in this algorithm:(1) a fuzzy measure is proposed to judge the noise ratio;(2)a gradient operator is introduced to save the thin lines,such as edge information.It gets some useful information by training and simulating.Compared with traditional median filter,ordering threshold switching median filter and improved median filter proposed by Sorin Zoican,our approach is more adaptive and receives better results.