How to convert white points

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jpsdr
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How to convert white points

Post by jpsdr » Sun Mar 18, 2018 11:42 am

Very nice result (and "fun" movie also).
I've been looking out for formula of how tweaking white point : converting (R0,G0,B0) with white point at (x0,y0) to (R1,G1,B1) with a white point at (x1,y1), but without success for now... :?
As you're talking about it, do you know where i can find it, or is it possible you could provide the formula which gives (R1,G1,B1) from [(R0,G0,B0),(x0,y0),(x1,y1)] ?
Actualy, i'm still in a "gathering information" stage.

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admin
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Re: HDR -> SDR tonemapping for DGDecodeNV

Post by admin » Sun Mar 18, 2018 12:32 pm

What is its significance for practical HDR->SDR conversion?

jpsdr
Posts: 180
Joined: Tue Sep 21, 2010 4:16 am

Re: HDR -> SDR tonemapping for DGDecodeNV

Post by jpsdr » Sun Mar 18, 2018 2:45 pm

I have no idea, i want to experiment several things, when you see fig.37 of BT.2390, it seems that white point scaling is a possibilty, so that's why i'm trying to figure out what is the formula. BT.709 define a fixed white point, in HDR, there is a white point information, so maybe it can be useful, maybe not...
As i said, i'm for now gathering all the informations i can, and after, i have some experiments i want to do.
Even if (i think) they'll probably fail... ;)
HDR seems to be a total mess, with a lot of aspects without any specification, with a "deals with it, and... do your best !" situation.
So, experiment... experiment... experiment...

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admin
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Re: How to convert white points

Post by admin » Sun Mar 18, 2018 2:58 pm

If you figure anything out be sure to let us know.


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admin
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Re: How to convert white points

Post by admin » Sun Mar 18, 2018 4:09 pm

Great links, thanks!

gonca
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Re: How to convert white points

Post by gonca » Sun Mar 18, 2018 4:17 pm

jspdr
Maybe if you tell us what experiments you are planning, we might be able to give more information.
Is it video encoding, digital photography?

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