添加噪声与平滑降噪,平滑降噪可采用定制的模板做滤波运算（就是卷积运算）来获得中心像素的新值，也可以对指定大小的邻域进行某些运算作为中心像素的新值.-Add noise and smooth noise reduction, smoothing noise reduction can be customized templates so filtering operation (that is convolution operation) to receive the new pixel valu