Search found 27 matches

by tarlack
Tue Aug 19, 2014 6:00 pm
Forum: Links & Papers
Topic: GACV : robust numerical integration method
Replies: 2
Views: 6761

GACV : robust numerical integration method

Hi there, we recently published a new method for Monte-Carlo-based numerical integration, named "Globally adaptive control-variate" (GACV). It has been published in the SISC journal (Society for industrial and applied mathematics - scientific computing). It's an hybrid between cubature rules and Mon...
by tarlack
Fri Jul 11, 2014 8:31 am
Forum: General Development
Topic: Weighting Paths in Light Tracing
Replies: 1
Views: 2799

Re: Weighting Paths in Light Tracing

I'm not really sure about that one, but I'll take it intuitively : consider a sensor, whose total area does not change: if less pixels are present, then each pixel receives more energy. This is what happens naturally with light tracing when you simply divide by the number of samples, so you don't ha...
by tarlack
Mon Jul 07, 2014 3:17 pm
Forum: General Development
Topic: Camera Weighting in Eye Tracing
Replies: 10
Views: 8359

Re: Camera Weighting in Eye Tracing

By the way, your questioning (which I find appreciable) makes me wonder: are there any renderer out there that goes from radiance to voltage through a correct sensor modeling, with the mosaicing of the sensor, its thermal behavior, ... ? This way we could simulate ISOs, dark frame noise, long exposu...
by tarlack
Mon Jul 07, 2014 3:12 pm
Forum: General Development
Topic: Camera Weighting in Eye Tracing
Replies: 10
Views: 8359

Re: Camera Weighting in Eye Tracing

I agree with you on most of the things, except the last one about how smallPT (and not specifically it, note that I did not use it) deals with exposure time/aperture. smallPT does not use a large aperture or extra shutter time. It just models a non physically-plausible sensor, whose response functio...
by tarlack
Mon Jul 07, 2014 7:00 am
Forum: General Development
Topic: Camera Weighting in Eye Tracing
Replies: 10
Views: 8359

Re: Camera Weighting in Eye Tracing

...the aperture size and exposition time affect the total amount of energy you will collect, which you compute using the equations of physically based rendering. The more samples the more precise, you can add extra weighting functions to simulate the effect of ISO or noise due to discrepancy of expo...
by tarlack
Mon Jul 07, 2014 6:47 am
Forum: General Development
Topic: Camera Weighting in Eye Tracing
Replies: 10
Views: 8359

Re: Camera Weighting in Eye Tracing

Well, we do not deal with real cameras here neither with real photons, we do not consider true monochromatic light propagation, but we deal with a virtual scene and a virtual world where an arbitrary number of spectral samples can be traced for any arbitrarily small interval of time. The pinhole cam...
by tarlack
Mon Jul 07, 2014 6:17 am
Forum: General Development
Topic: Camera Weighting in Eye Tracing
Replies: 10
Views: 8359

Re: Camera Weighting in Eye Tracing

Why would the exposure time be infinite because the camera is a pinhole ? In rendering I don't see any link between time and aperture size. In the limit, as ingenious said, the basic setup is to consider a dirac in time, and you simulate for a single value of time. In rendering, we can simulate a lo...
by tarlack
Wed Jul 02, 2014 9:01 am
Forum: General Development
Topic: understanding sampling, filters, motion blur, DoF,...
Replies: 14
Views: 9156

Re: understanding sampling, filters, motion blur, DoF,...

Well, the 4D BVH is just like a 3D BVH, but splitting according to time is also allowed => no more loose bboxes. The 3D bbox + 1D time split is just a special and largely suboptimal case of a 4D BVH. The ray/geometry intersection is 4D as well, but finding an accurate intersection with an arbitraril...
by tarlack
Tue Jul 01, 2014 6:54 am
Forum: General Development
Topic: understanding sampling, filters, motion blur, DoF,...
Replies: 14
Views: 9156

Re: understanding sampling, filters, motion blur, DoF,...

@friedlinguini : don't you have structured aliasing patterns with your approach ? I remember blender doing this, and the number of images to avoid ghosting effects were large as soon as an object was going really fast relatively to the aperture time. For instance, reproducing a long exposure time ph...