Lookup table question.

Mark Davey (mkd@medphys.ucl.ac.uk)
Thu, 12 Aug 1999 16:17:49 -0700

• Next message: JB West: "Re: Perspective distortion on IMPACTs"
• Previous message: Fred Dech: "Re: texture quandery."
• Next in thread: Dave Akers: "Re: Lookup table question."
• Reply: Dave Akers: "Re: Lookup table question."
• Reply: Chikai Ohazama: "Re: Lookup table question."
• Maybe reply: Chikai Ohazama: "Re: Lookup table question."

Could anyone please give me an explanation for how lookup tables work
when the data is of type RGBA.
There are therefore many millions of possible RGBA values for each
voxel. How are these mapped to a lookup table of say, 256 values as is
the case with the demo

voglRaw 0 256 256 49 ubyte4 -sc 1 1 2 \
  -color -lut 50 55 \
  $DATAPATH/dose+ct10*ima

Here an RGBA data set is loaded and the middle mouse button makes
changes to a lookup table containing 256, RGBA lookup values.

So, to re-iterate, how is the lookup achieved?

Regards
Mark...

-- 
From: Mark Davey
Dept. of Medical Physics, UCL.

TEL: +44 (0)171 915 1673.
FAX: +44 (0)171 837 9279.

Institute of Laryngology and Otology,
330 Gray's Inn Road,
London.
WC1X 8GE.

• Next message: JB West: "Re: Perspective distortion on IMPACTs"
• Previous message: Fred Dech: "Re: texture quandery."
• Next in thread: Dave Akers: "Re: Lookup table question."
• Reply: Dave Akers: "Re: Lookup table question."
• Reply: Chikai Ohazama: "Re: Lookup table question."
• Maybe reply: Chikai Ohazama: "Re: Lookup table question."

This archive was generated by hypermail 2.0b2 on Mon Nov 01 1999 - 14:21:40 PST