LEEFILT

The LEEFILT function performs the Lee filter algorithm on an image array using a box of size 2 N +1. This function can also be used on vectors. The Lee technique smooths additive image noise by generating statistics in a local neighborhood and comparing them to the expected values.

This routine is written in the IDL language. It is based upon the algorithm published by Lee ( Optical Engineering 25(5), 636-646, May 1986). Its source code can be found in the file leefilt.pro in the lib subdirectory of the IDL distribution.

Calling Sequence

Result = LEEFILT( A [, N [, Sig]] )

Arguments

A

The input image array or one-dimensional vector.

N

The size of the filter box is 2 N +1. The default value is 5.

Sig

Estimate of the standard deviation. The default is 5. If Sig is negative, IDL interactively prompts for a value of sigma , and displays the resulting image using TVSCL (for arrays) or PLOT (for vectors). To end this cycle, enter a value of 0 (zero) for sigma .

Keywords

EXACT

Set this keyword to apply a more accurate (but slower) implementation of the Lee filter.

See Also

DIGITAL_FILTER , , SMOOTH , VOIGT