Search found 22 matches

by toshiya
Mon Jan 27, 2014 2:48 pm
Forum: General Development
Topic: Choosing clamping limit in VPL rendering
Replies: 13
Views: 9603

Re: Choosing clamping limit in VPL rendering

A very easy and relatively robust solution is to only clamp the final pixel contribution to some maximum value, say 10. This way you make sure that a single VPL cannot contribute huge amount of energy (either due to low PDF, due to landing around a corner, or due to a sharp BRDF). This parameter is...
by toshiya
Thu Nov 28, 2013 9:58 am
Forum: General Development
Topic: Frame buffer for spectral rendering
Replies: 8
Views: 6551

Re: Frame buffer for spectral rendering

I also have a code that does RGB <-> spectrum conversions in my gpusppm:

http://cs.au.dk/~toshiya/gpusppm.zip

I've tested the code and it should be fairly accurate in the sense that RGB -> spectrum -> RGB well recovers the original RGB value. It's based on that paper with some improvement.
by toshiya
Wed Nov 27, 2013 11:28 am
Forum: General Development
Topic: Frame buffer for spectral rendering
Replies: 8
Views: 6551

Re: Frame buffer for spectral rendering

The correct order is, accumulation, tone mapping, and then gamma/color correction. You can think of accumulation of spectral contributions as a part of Monte Carlo integration, which should be done before any image processing like tone mapping and gamma correction. Having said that, if you can easil...
by toshiya
Fri Sep 20, 2013 2:50 pm
Forum: General Development
Topic: A note on PPM/VCM with specrtal rendering and motion blur
Replies: 9
Views: 7432

Re: A note on PPM/VCM with specrtal rendering and motion blu

You can see this approach in action in my gpusppm :-> Anton is right that this approach is prone to banding artifacts. However, with enough samples (to the extent that the purely random approach also converges), I don't necessarily find this correlated approach inferior. Theoretically, both have the...
by toshiya
Fri Sep 20, 2013 10:39 am
Forum: General Development
Topic: A note on PPM/VCM with specrtal rendering and motion blur
Replies: 9
Views: 7432

Re: A note on PPM/VCM with specrtal rendering and motion blu

Can't you just turn it into two dimension by randomizing a common time and wavelength for each pass? I thought it was standard practice for sppm class of algorithms. I'm probably missing some important details.... That's how I did motion blur in SPPM, and it also works fine for spectral rendering. ...
by toshiya
Mon Jan 28, 2013 10:57 am
Forum: Links & Papers
Topic: Path Space Regularization
Replies: 12
Views: 11855

Re: Path Space Regularization

But that's what is visible in the pics though.. (and the pics that don't show it, have been run for a very long time) You are right. Maybe my question is whether directional blur has some good properties for the combination with MCMC which spatial blur does not have. From http://igad2.nhtv.nl/ompf2...
by toshiya
Mon Jan 28, 2013 10:42 am
Forum: General Development
Topic: Question about BDPT with pinhole camera model.
Replies: 16
Views: 10412

Re: Question about BDPT with pinhole camera model.

VCM = vertex merging + BPT, that's why I claimed it outperforms (S)PPM. Sorry for my misunderstanding :-> SPPM \approx VM (vertex merging) and VCM = VM + BPT indeed. Another difference to note here is that the MCMCPPM does still employ path reusing, whereas Anton's modified MLT does not. Therefore,...
by toshiya
Mon Jan 28, 2013 9:25 am
Forum: Links & Papers
Topic: Path Space Regularization
Replies: 12
Views: 11855

Re: Path Space Regularization

I wonder why you do not run into the problem of very high variance of BRDFs? Even though mollification essentially blurs out the delta function of specular materials, wouldn't it still result in a very large value (or very small value) when you apply this idea to connection paths?
by toshiya
Mon Jan 28, 2013 9:22 am
Forum: General Development
Topic: Question about BDPT with pinhole camera model.
Replies: 16
Views: 10412

Re: Question about BDPT with pinhole camera model.

BTW, VCM seems like a very great GI algorithm! Is it the current state of the ait, out performing SPPM, MLT? It definitely outperforms SPPM, but not necessarily MLT. The last path space regularization paper of Anton Kaplanyan shows a kitchen scene where MLT can outperform VCM. It's a rather extreme...
by toshiya
Fri Oct 12, 2012 10:56 am
Forum: Links & Papers
Topic: Vertex merging paper and SmallVCM
Replies: 33
Views: 30916

Re: Vertex merging paper and SmallVCM

I just want to add that we are also planning to release an example code for our paper ""A Path Space Extension for Robust Light Transport Simulation", which basically results in the same algorithm as VCM :-> Our code will not be as fancy as ingenious', but I hope it will further help people to under...