| Re: 32 bits IMAGES [message #6930] |
Fri, 30 August 1996 00:00 |
peter
Messages: 80
Registered: February 1994
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Mario Noyon (mnoyon) wrote:
: How can I precise (if I can do it) how many bits represent a pixel. Can I tell
: somewhere that a pixel is represnted by 8, 16, or 32 bits.
: I want to visualize indeed 32 bits images.
If they are 32 bit grayscale, then you need to map them to 8 bit, since
that is all the grayscales that IDL (and probably your monitor)
supports. BYTSCL is the appropriate command.
Depending on your platform, even 8 bits (256 levels) is optimistic,
because you'll run out of colormap entries first. For displaying
medical imagery, I normally use a 7 bit gamma corrected gray ramp as the
first 128 entries in my color table, leaving the upper part of the table
for highlight colors, etc. The gamma correction is essential for not
losing the darker parts of the image. To window/level the image, the
edges of the gray ramp are moved in and out. If you'd like a routine
that implements this, drop me a line.
Peter
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