应用多种滤波器进行处理：算术均值，几何 均值，谐波均值，逆谐波均值，中值滤波， 中点滤波，最大值、最小值滤波等,To deal with a variety of filter applications: arithmetic mean, geometric mean, harmonic mean, inverse harmonic mean, median filter, the mid-point filtering, maximum, minimum filtering

spatial filter for spatial domain filtering