# filterDoog

## PURPOSE

n-dim difference of offset Gaussian DooG filter (Gaussian derivative).

## SYNOPSIS

function dG = filterDoog( dims, sigmas, nderivs, show )

## DESCRIPTION

     n-dim difference of offset Gaussian DooG filter (Gaussian derivative).

     Creates a nd derivative of Gaussian kernel.  For all but d==1 use
     primarily for visualization purposes -- for filtering better to use the
     indvidiual seperable kernels for efficiency purposes.

     USAGE
      dG = filterDoog( dims, sigmas, nderivs, [show] )

     INPUTS
      dims    - nd element vector of dimensions of final Gaussian
      sigmas  - sigmas for nd Gaussian
      nderivs - order of derivative along each of the nd dimensions
      show    - [0] figure to use for optional display

     OUTPUTS
      dG      - The derivative of Gaussian filter

     EXAMPLE
      dG1 = filterDoog( 43, 2, 3, 1 ); %1D
      dG2 = filterDoog( [41 41], [3 3], [1,1], 2 ); %2D
      dG3 = filterDoog( [101 101 101], [4,4,10], [1,1,0], 3 ); %3D

     See also FILTERGAUSS, NORMPDF2, FILTERDOG2D, FILTERGABOR2D

     Piotr's Image&Video Toolbox      Version 2.0
     Copyright 2008 Piotr Dollar.  [pdollar-at-caltech.edu]
     Please email me if you find bugs, or have suggestions or questions!
     Licensed under the Lesser GPL [see external/lgpl.txt]

## CROSS-REFERENCE INFORMATION

This function calls:

- filterGauss n-dimensional Gaussian filter.
- filterVisualize Used to visualize a 1D/2D/3D filter.

This function is called by:

- FbMake Various 1D/2D/3D filterbanks (hardcoded).