Spatial filtering

Question 1

what is the purpose of spatial filtering?

Answer 1

1. image smoothing (reduces and supresses noise)
2. image sharpening (highlights edges by removing blur)

Question 2

Image smoothing

Answer 2

1. define filter. identical weights sum to 1 to preserve overall brightness
2. central pixel is in middle of neighbourhood
3. calc new pixel value. multipy all pixel vaule by corresponding weight then sum for centre
4. repeat one pixel at a time for whole image