POV-Ray : Newsgroups : povray.unofficial.patches : POVRay 3.7 with depth-map unofficial patch release : Re: POVRay 3.7 with depth-map unofficial patch release Server Time
28 Sep 2021 14:46:02 EDT (-0400)
  Re: POVRay 3.7 with depth-map unofficial patch release  
From: handos
Date: 17 Jul 2011 18:10:01
Message: <web.4e235c90554df4f5b166303d0@news.povray.org>
Hi Le,

Thanks for having spent time on this. I understand that it's not cleaned up yet
but it's just a small rudimentary version of the patch I created. I'd take your
advice and clean up a bit so that it's easy for other guys to understand.
My intention here was to just get some good feedback on it.

Regarding the purpose, there are many applications in computer vision or
graphics where one would like to have a depth-map corresponding to the image.
And one might need to obtain 3D coordinates for each pixel observed in the image
to aid  3D reconstruction or applications related to Augmented Reality. I had
searched in the POVRay website to see if anyone had done that before with
POVRay-3.7. I guess maybe working on depth-map is quite specific but just in
case anyone wanted to have a depth-map along with image, it might be worth
taking a look at this patch I released.

I'd definitely add the original version of 3.7 into my git-hub so that it's easy
to find out the patches I created.

Thanks a lot!

Le_Forgeron <jgr### [at] freefr> wrote:
Le 17/07/2011 18:32, handos nous fit lire :
> > Dear everyone,
> >
> > I'd like to let you guys know of the recent change I made to the source code of
> > POVRay-3.7 to get the depth-map and camera parameters alongside
> > original image. Depth-maps are quite essential and important if one wants to
> > work on the 3D structure of the environment e.g. People in SLAM (Simultaneous
> > Localisation and Mapping), dense optical flow computation (Lucas Kanade 2.5D)
> > and ESM (Efficient Second Order Minimisation for image registration). It was
> > easy to get the depth-map with MegaPOV using PP_Init_Depth() directive function
> > but for scenes which take a lot of time to render e.g. Jaime's office scene
> > (Presistence of Ignorancia), POVRay-3.7 reduces a dramatic overhead in time by
> > multi-threading. So, in order to get the depth-map I had to change the 3.7 code
> > at some places and I was happy to get the depth-map without much hassles. I'd
> > also like to thank the suggestions I received on this forum to help me figure
> > out where do I need to change the code.
> >
> > I've kept the code here at my git-hub[
> > https://github.com/ankurhanda/povray.3.7.0.RC3.withdepthmap]. Please feel free
> > to download the code and try it out yourself. Please find the README_ANKUR file
> > here at
> >
> > to get started. I'd be very keen on your suggestions, complaints and comments.
> Why did you commit the compiled files too ?
> And left "cout <<" in code ? with getchar() too ?
> The postproc directory seems to be a left-over of first design.
> Some files have been updated only to have traces which are now in comments.
> (So, to summarise gently: clean up is needed)
> Also a shame you did not put unmodified 3.7RC3 as some step in your git,
> looking for your patches would have been easier.
> The depthArray (or whatever its name) could need to be disk-buffered
> (transparently, same as -IM/-MI option) for large picture.
> I'm not sure I understand the purpose & behaviour of the Depth Patch.
> Nor why you needed the F_Triangle_Patch from megapov either.

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