Level 2 Help for REMRAY

1. Input image.
2. Median image generated with a 3 by 3 or a 5 by 5 filter.
   The filter size should exceed the artifact size by a factor of 2.

output image with artifacts removed.

Tolerance threshold. Defaults to 20.
Used to automatically set the GAIN1 and GAIN2 keywords if they are not 
specified.

Intensity gain factor. 
Used to compute a threshold proportional to the local median.
The default is to compute it from TOL and the maximum dn in the image:
GAIN1=TOL/(max dn of medians)
Pixels are changed if their median values exceed  a total 
threshold composed of
GAIN1*median + GAIN2*activity.

Activity gain factor.
Used to compute a threshold proportional to the unevenness of the local scene.
The default is to compute it from TOL and the maximum activity in the image:
GAIN2=TOL/(max activity of medians).
Activity is the absolute value of a derivative filter:
-1 -1 -1
-1  8 -1
-1 -1 -1
Pixels are changed if their median values exceed  a total 
threshold composed of
GAIN1*median + GAIN2*activity.