Rank Filtering

• Similar to Convolution
• Take values under the kernel/mask/filter window, and order them on intensity
  • pick
    • First: minimum/erosion
    • Last: maximum/dilation
    • Middle value: median filtering
    • Other: e.g. 7th of 9 in a 3x3 window

Median Filtering

• better than mean filtering or spatial averaging ( see Spatial Averaging)
  • removes noise and smoothens while keeping edges
  • especially useful with salt and pepper noise