LOGLUT Name
LOGLUT Purpose
Return a log lookup table useful for scaling images.
Category
Calling Sequence
lut = loglut(lo,hi) Inputs
lo = image value to map to 0. in
hi = image value to map to 255. in
where lo GE 0, hi GT lo.
Keyword Parameters
Keywords
EXPONENT=ex Controls curvature of transformation (def=1).
Use values in the range -15 to 15, 0 gives a straight
line, <0 negative curvature.
GLO=glo Min color to use: image value lo maps to glo.
Default is 0.
GHI=ghi Max color to use: image value hi maps to ghi.
Default is top available color.
/REVERSE means reverse color table.
/ROUND means round lookup table values to nearest integer.
Outputs
lut = resulting lookup table. out
Common Blocks
Notes
Note: image values beyond given lo and hi get clipped.
Ex: let A be a 16 bit image with values ranging from
850 to 12000. Assume the image values from 900 to
2000 are to be scaled to 0 to 255 using a log curve.
lut = loglut(900,2000,exp=1.5) ; Set up table.
b = lut(a) ; Do scaling.
Modification History
R. Sterner, 1998 Nov 6
R. Sterner, 1998 Nov 10 --- Added /TOP.
R. Sterner, 2010 Jun 07 --- Converted arrays from () to [].
Copyright (C) 1998, Johns Hopkins University/Applied Physics Laboratory
This software may be used, copied, or redistributed as long as it is not
sold and this copyright notice is reproduced on each copy made. This
routine is provided as is without any express or implied warranties
whatsoever. Other limitations apply as described in the file disclaimer.txt.