POV-Ray : Newsgroups : povray.unofficial.patches : Rad_data vs Halton , a quantitative comparison Server Time
3 Jul 2024 05:20:14 EDT (-0400)
  Rad_data vs Halton , a quantitative comparison (Message 1 to 7 of 7)  
From: Mael
Subject: Rad_data vs Halton , a quantitative comparison
Date: 7 Jan 2003 02:16:21
Message: <3e1a7ec5$1@news.povray.org>
http://195.221.122.126/samples/erreur.html

M


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From: George Pantazopoulos
Subject: Re: Rad_data vs Halton , a quantitative comparison
Date: 7 Jan 2003 02:18:54
Message: <3e1a7f5e$1@news.povray.org>
Very interesting Mael. Is your Halton sequence a precomputed, drop-in
replacement for rad_data[1600] ?

George


"Mael" <mae### [at] hotmailcom> wrote in message
news:3e1a7ec5$1@news.povray.org...
> http://195.221.122.126/samples/erreur.html
>
> M
>
>


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From: Christoph Hormann
Subject: Re: Rad_data vs Halton , a quantitative comparison
Date: 7 Jan 2003 04:09:09
Message: <3E1A9934.17AB19A0@gmx.de>
Mael wrote:
> 
> http://195.221.122.126/samples/erreur.html
> 

Intersting, your halton sequences always seemed too random for good
results to me.  Does the difference also show up in the actual renders?

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
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Last updated 31 Dec. 2002 _____./\/^>_*_<^\/\.______


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From: Mael
Subject: Re: Rad_data vs Halton , a quantitative comparison
Date: 7 Jan 2003 04:22:31
Message: <3e1a9c57@news.povray.org>
> Intersting, your halton sequences always seemed too random for good
> results to me.

May be some sequences can do better, if you send me your set of points I can
try to add the curve I get with it
However monte carlo methods does work with random sequences, and quasi monte
carlo with pseudo random sequences (and in pseudo random there is still random
:)

> Does the difference also show up in the actual renders?

I've not tried visual tests. Note that the 0.2 difference between 1600
rad_data and 1600 halton if equally dispatched on the 1053 locations only
represents a small amount of illuminance ..

I think I should also have traced the curve for the max error

M


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From: Mael
Subject: Re: Rad_data vs Halton , a quantitative comparison
Date: 7 Jan 2003 07:45:37
Message: <3e1acbf1$1@news.povray.org>
> http://195.221.122.126/samples/erreur.html

Updated with curves for a 300 points set by Christoph Hormann, and also added
curves for the max error

The scene rendered for 50 samples for the three distributions
http://195.221.122.126/samples/erreur_images.html
this is low quality radiosity :
1 pass (about 1000 points where illuminance is gathered), high error_bound
(but the aim was to evaluate the quality of the gathering part, not the whole
radiosity algorithm :)

M


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From: Thorsten Froehlich
Subject: Re: Rad_data vs Halton , a quantitative comparison
Date: 7 Jan 2003 09:19:35
Message: <3e1ae1f7$1@news.povray.org>
In article <3e1acbf1$1@news.povray.org> , "Mael" <mae### [at] hotmailcom> 
wrote:

>> http://195.221.122.126/samples/erreur.html
>
> Updated with curves for a 300 points set by Christoph Hormann, and also added
> curves for the max error
>
> The scene rendered for 50 samples for the three distributions
> http://195.221.122.126/samples/erreur_images.html
> this is low quality radiosity :
> 1 pass (about 1000 points where illuminance is gathered), high error_bound
> (but the aim was to evaluate the quality of the gathering part, not the whole
> radiosity algorithm :)

Pardon my ignorance, but I see no real difference in any of the
pictures...???

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org


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From: Mael
Subject: Re: Rad_data vs Halton , a quantitative comparison
Date: 7 Jan 2003 19:06:53
Message: <3e1b6b9d$1@news.povray.org>
A little precision about those graphs :
The curves don't give any indication about the visual aspect of the images.
They only measure a distance to an 'exact' solution.
Particularly for low count the pov image can be smooth and look good (but be
far from the exact solution) and the halton image have artifacts (but be
statistically closer to the exact solution)

M


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