COMOS comes with a lookup tabble called LIMITCOL that is designed to turn
all parts of the image below a level (like grey values of 5) green and
one above a high level (say, 240) full red. This make identification of
truncated areas REAL obvious on screen.
To make one yourself, start with a grey-scale spectrum in the screen
for editing your LUT (with red, green, and blue all going diagonally
and linerally from the lower left to the upper right). Select the green
and draw the line straight to the top at value 0 to 5, then down to the
origional diagnal (for the rest of the ride to the upper left as before).
At the high end, drop the green and blue lines to zero for the last few
pixels above, say, 240. This should do the trick.
I am doing this from memory and it may be faulty (my meory and these
instructions), but if you can't get this to work, reply and I'll check
the spectum out in COMOS and verify it's spec.
Make sure you save it and set the check box to 'hold lut's'. This will
allow you to aquire in direct mode (fast or slow) and adjust your gain
and black level to get rid of the green and red (thereby avoiding
truncation of data). This also works great for 'aquire to #' to determine
how many passes to make (and how to change your adjustment) to reach a
good black level with a given number of passes per image (works great to
set up for a 3-d data set by standardising the number of passes per image
prior to starting aqusition of the entire 3-d data set --- If your sisnal
(that's SIGNAL) is weak, 'aquire to peak' can spend too much time on a
section outside of your sample and bleach it for the rest of the data
set.
Hope this help, if you have any questions or problems, drop me a note.....
God Luck!
 
Brett Telegan
Research Specialist II
Department of Dermatology
University of Pennsyalvania
(215)898-3469
[log in to unmask]