[Chimera-users] same volume data values over the entire volume

[Dieter Blaas]

Hi,

     Trying to color a volume according to "volume data" I get the same 
numerical values for all colors and a speckled appearance. When using 
"volume data gradient norm" I get the expected colors, i.e. strong local 
changes of the volume data are red and spots where there is essentially 
no change are in blue. How is this possible? If I understand correctly, 
"volume data gradient norm" colors according to the first derivative of 
"volume data" or is this wrong?  Do I need something like a normalization?

Thanks a lot for explanations,

best, Dieter

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Dieter Blaas,
Max F. Perutz Laboratories
Medical University of Vienna,
Inst. Med. Biochem., Vienna Biocenter (VBC),
Dr. Bohr Gasse 9/3,
A-1030 Vienna, Austria,
Tel: 0043 1 4277 61630,
Fax: 0043 1 4277 9616,
e-mail: dieter.blaas at meduniwien.ac.at
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