3e0b58b7$1@news.povray.org...

> POV does internal work with high
> dynamic range and I guess most of you have already used a light source
that is
> "brighter" than rgb <1,1,1>. I usually do so and this is the way Jaime's
lighting
> system does work. This is also "HDR".

In fact my question was more, given a normal LDR image with variation of
intensity clipped between 0 and 1, is it possible to create directly a HDR
image by calculating the intensity value from the clipped one, by using a
function I=f(r,g,b) with I being maximum (and much higher than 1 of course)
for White? As I said, HDR shop accepts to do this but I'm not sure that the
final image really has hot spots (but then I have not tested this
extensively).
In any case, creating HDR maps within POV-Ray would be sweet.

G.

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> In fact my question was more, given a normal LDR image with variation of
> intensity clipped between 0 and 1, is it possible to create directly a HDR
> image by calculating the intensity value from the clipped one, by using a
> function I=f(r,g,b) with I being maximum (and much higher than 1 of course)
> for White?

No. If the data is clipped (like POV output) how should it be recovered. If
the data is compressed (like done with Kari's patch) there is no need to use
HDR shop, simply usse a higher ambient value, but the quality will not be the
same as with "real" hdr data. .

>As I said, HDR shop accepts to do this but I'm not sure that the
> final image really has hot spots (but then I have not tested this
> extensively).

To recreate HDR data you'll need a couple of images (lets say 5 to 10
more are better) with different exposer, this works fine.

-Ive

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> In fact my question was more, given a normal LDR image with variation of
> intensity clipped between 0 and 1, is it possible to create directly a HDR
> image by calculating the intensity value from the clipped one, by using a
> function I=f(r,g,b) with I being maximum (and much higher than 1 of
course)
> for White?

From a single image, you could only approximate it. All of the clipped areas
(large areas of pure white or pure black) would have to be guessed about.

 - Slime
[ http://www.slimeland.com/ ]

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