中文说明：最简单的平滑滤波是将原图中一个像素的灰度值和它周围邻近8个像素的灰度值相加，然后将求得的平均值（除以9）作为新图中该像素的灰度值。这种方法称为邻域平均法，它采用模板计算的思想，模板操作实现了一种邻域运算，即某个像素点的结果不仅与本像素灰度有关，而且与其邻域点的像素值有关。 邻域平均处理方法是以图像模糊为代价来减小噪声的，且模板尺寸越大，噪声减小的效果越显著。如果f(x,i) 是噪声点，其邻近像素灰度与之相差很大，采用邻域平均法就是用邻近像素的平均值来代替它，这样能明显消弱噪声点，使邻域中灰度接近均匀，起到平滑灰度的作用。因此，邻域平均法具有良好的噪声平滑效果，是最简单的一种平滑方法. -
English Description：
The simplest smoothing filter is to add the gray value of a pixel in the original image and the gray value of 8 neighboring pixels, and then take the average value (divided by 9) as the gray value of the pixel in the new image. This method is called neighborhood average method. It adopts the idea of template calculation. Template operation realizes a neighborhood operation, that is, the result of a pixel is not only related to the gray level of the pixel, but also related to the pixel value of its neighborhood.