[Radiance-general] dynamic range - RGBE

[Gregory J. Ward]

Hi Despina,

This is all explained in detail at:

	http://www.anyhere.com/gward/hdrenc/

-Greg

> From: "Despina Michael" <despina_m81 at hotmail.com>
> Date: March 30, 2005 1:45:18 AM PST
>
> Thanks again,
>
> well..  I have a couple questions again, on this
> 1. In the paper "High Dynamic Range Image Encodings" is mentioned that 
> RGBE format cannot cover the visible gamut.
> I can not understand this since RGBE supports 76 order of magnitudes 
> and our eye can see luminances between 10 ^ 6 - 10 ^-7 that is ontly 
> 13 orders of Magnitudes.
> The only thing that I can think is that propaply RGBE can not encode 
> small steps of change for luminance. Is that the reason that RGBE 
> cannot cover the visible gamut?
>
> 2. and my second question is what we mean by relative precision of an 
> hdr image format? Is the smallest step (change of lumminance) that 
> format supports? (and why we measure it in %?)
> If it is so, when the value of relative precision is greater means 
> that we have greater precision (smaller step) or the opposite?
>
> Despina