#
vcm

## Median

The Script call is:-

## vcm.Median (clip[, int maxgrid = 5] [,int plane=[1,0,0] ] );

clip: input clip all formats except Compat.
maxgrid: maximum size of square grid to which grid can grow fom 3x3 for getting good statistics. Odd number 3 to 11.
plane: input clip color planes to be processed. If set to 0, will not process and if set to 1 will be processed. All 3 values must not be simultaneously specified as zero.

Median Filter is for eliminating certain types of impulsive noise. It uses local statistics (minimum, maximum and Median values) of a moving local grid, and changes grid size depending on local statistics.

As per theory
Quote "Ordinary Median filters perform well as long as the spatial density of impulsive noise is small. Adaptive Median filter can handle impulsive noise having larger probablity. An additional benefit is this seeks to preserve detail while smoothing nonimpulse noise something that the traditional Median filter does not do.

The algorithm used has three purposes.
1.To remove salt and pepper (impulse) noise.
2.To smooth other noise which may not be impulsive
3.To reduce distortion such as excessive thinning or thickening of object boundaries.
" unquote