# Filters

This section is still incipient and contains only a couple of filtering options:

- Smooth (SUSAN) - SUSAN nonlinear noise reduction reduces noise, ideally without blurring the underlying image. For details on this technique see users.fmrib.ox.ac.uk/~steve/susan
- Median (3x3) - Reduces noise in the image by replacing each pixel with the median of the neighboring pixel values over a 3x3 window
- Adaptive Median – Uses an algorithm taken from the Digital Image Processing Using Matlab book. It is a filter capable of adapting its behavior depending on the characteristics of the image in the area being filtered.
- STD – Computes a local standard deviation of image where each output pixel contains the standard deviation value of the 3-by-3 neighborhood around the corresponding pixel in the input image.
- Min – Retains the minimum of the 9 values inside the 3x3 kernel neighborhood around the corresponding pixel in the input image.
- Max – Same as above, but retains the maximum.
- Range STD – Computes a local range of image where each output pixel contains the range value (maximum value - minimum value) of the 3-by-3 neighborhood around the corresponding pixel in the input image.

Copyright © <2010>, <Joaquim Luis>

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