##
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.