多方向几何非线性扩散图像去噪方法

摘要

As the direction of edges in images is not taken into account,the original geometric nonlinear diffusion filter (GNLDF)is not in the best state for images denoising,which diffuses only in the horizontal and vertical directions.In this study,we detected the edges and their directions in images based on the magnitude of the gradient in the direction of the eight neighborhoods of each pixel,then conducted GNLDF at the edge pixel j ust along the directions of the edges while at any no edge pixel along all four directions. Experiment results of five typical images with five levels of noise intensity show that the proposed method can not only effectively remove the noise but also better protect the edges in images.%现有几何非线性扩散滤波器同时在水平和垂直方向进行扩散，没有考虑图像边缘的方向性，有损其去噪效果．提出根据像素8邻域方向的梯度值检测边缘点及其边缘方向，对边缘点仅沿该边缘方向进行几何非线性扩散，而对非边缘点进行4个方向上的几何非线性扩散．5个等级噪声强度和5个典型加噪图像去噪实验结果表明，本文方法能够更有效地去除图像中的噪声，同时更好地保护图像边缘．