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Date: Tue, 9 Sep 2008 00:02:39 -0700 (PDT)
From: acanicio <acanicio@astrosnap.com>
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Subject: Re: [Tiff] SAMPLEFORMAT_IEEEFP
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Dear Bruce and Chris,

Thank you !
I didn't know that floating point values had to be between 0 and 1 !! 
When converting to float, I kept the original range, i.e. 0..255 when coming
from 8 bits, 0..65535 when coming from 16 bits, and 0..4294967295.

What do you mean by "Use the exposure adjustment " ? Is there some specific
tag for this or is it the same thing as scaling down ?. I see tag
TIFFTAG_REFERENCEBLACKWHITE in the specifications. Is that it ? 

I'll try as you say, thank you very much to both of you.

Best regards
Axel




Chris Cox wrote:
> 
> 
> Use the exposure adjustment and scale the values down.
> 
> Most of the time, you should scale your white point to something near 1.0
> to
> ensure visibility.
> 
> Chris
> 
> 
> 
> 
> 
> On 9/7/08 4:18 PM, "acanicio" <acanicio@astrosnap.com> wrote:
> 
>> But I have no luck with floating point values. I use SAMPLEFORMAT_IEEEFP
>> sample format along with 32 bits per sample.
>> All the pixel values are issued from an 8 bit/sample image, with no
>> conversion or multiplication applied to them.
>> When I open the file with some well known image editor, the image is
>> completely saturated, all white with values 32767...
>> Where should I look ?
> 
> _______________________________________________
> Tiff mailing list: Tiff@lists.maptools.org
> http://lists.maptools.org/mailman/listinfo/tiff
> http://www.remotesensing.org/libtiff/
> 
> 

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