| iTool User's Guide: Working with Surfaces |

## Filtering a Surface

Three types of filters are available in the iSurface tool: smooth filtering and convolution filtering.

### Convolving a Surface

To convolve a surface:

1. Select the surface to be convolved.

2. Select Operations Filter Convolution.

For details on using the convolution filter, see Convolution Filter.

### Median a Surface

The median filter replaces each point with the median (a value in an ordered set of values with an equal number of values above and below it) of the one- or two-dimensional neighborhood of a given width.

to median a surface:

1. Select the surface.

2. Select Operations Filter Median.

For details about using the median filter, see Median Filter.

### Smoothing a Surface

The smooth filter removes unwanted noise from a surface.

To apply the smooth filter to a surface:

1. Select the surface.

2. Select Operations Filter Smooth.

For details on using the smooth filter, see Smooth Filter.

IDL Online Help (March 01, 2006)