说明：  均值滤波器，对图像做均值滤波。均值滤波是典型的线性滤波算法，它是指在图像上对目标像素给一个模板，该模板包括了其周围的临近像素，再用模板中的全体像素的平均值来代替原来像素值。
(Mean filter, the image so mean filter. Mean filter is a typical linear filter algorithm, which is the target pixel on the image to a template that includes the adjacent pixels around it, and then all the pixels in the template to replace the original pixel value average.)