DIPlib Documentation - ©1995-2013 Quantitative Imaging Group, Delft University of Technology.

# GaussianSigma

Adaptive Gaussian smoothing filter

## SYNOPSIS

`#include "dip_filtering.h"`

dip_Error dip_GaussianSigma ( in, out, boundary, sigma, gaussSigma, outputCount, truncation )

## DATA TYPES

integer, float

## FUNCTION

The GaussianSigma filter is an adaptive `Gauss`-ian smoothing filter. The value of the pixel under investigation is replaced by the Gaussian-weighted average of the pixelvalues in the filter region which lie in the interval `+/- 2 sigma` from the value of the pixel that is filtered. The filter region is specified by `gaussSigma` and `truncation`. If `outputCount` is `DIP_TRUE`, the output values represent the number of pixel over which the average has been calculated. When `threshold` is `DIP_TRUE`, the pixel intensities are thresholded at `+/- 2 sigma`, when it is set to `DIP_FALSE`, the intensities are weighted with the Gaussian difference with the intensity of the center pixel.

With `threshold` set to `DIP_FALSE`, this filter is also known as the bilateral filter.

## ARGUMENTS

Data type | Name | Description
`dip_Image` | `in` | Input image
`dip_Image` | `out` | Output image
`dip_BoundaryArray` | `boundary` | Boundary conditions
`dip_float` | `sigma` | Sigma
`dip_FloatArray` | `gaussSigma` | Sigma of Gaussian
`dip_Boolean` | `outputCount` | Output the Count
`dip_float` | `truncation` | Truncation of Gaussian, see `GlobalGaussianTruncationGet`

## LITERATURE

John-Sen Lee, Digital Image Smoothing and the Sigma Filter, Computer Vision, Graphics and Image Processing, 24, 255-269, 1983

## SEE ALSO

`Sigma`, `BiasedSigma`, `Gauss`