POV-Ray : Newsgroups : povray.general : how to define the focal length and the principal point of a camera in pov r= Server Time
17 Aug 2022 22:36:09 EDT (-0400)
  how to define the focal length and the principal point of a camera in pov r= (Message 1 to 4 of 4)  
From: 6digit
Subject: how to define the focal length and the principal point of a camera in pov r=
Date: 18 Jul 2022 09:35:00
Message: <web.62d56056c11de4414eb0f47cfb08dd02@news.povray.org>
good evening,

I recently calibrated a camera to get the intrinsic and extrinsic parameters. my
main goal is to mimic the perspective camera in pov ray with that of the real
one. I was wondering if it's possible to define the focal length and principal
point of the perspective camera located in pov ray. I read through this
documentation <http://www.povray.org/documentation/view/3.6.1/246/> but it
doesn't seem to mention any about defining a focal length and principal point.
any tips?

thank you

regards 6digit


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From: Alain Martel
Subject: Re: how to define the focal length and the principal point of a camera in pov r=
Date: 18 Jul 2022 11:10:33
Message: <62d577e9@news.povray.org>
Le 2022-07-18 à 09:29, 6digit a écrit :
> good evening,
> 
> I recently calibrated a camera to get the intrinsic and extrinsic parameters. my
> main goal is to mimic the perspective camera in pov ray with that of the real
> one. I was wondering if it's possible to define the focal length and principal
> point of the perspective camera located in pov ray. I read through this
> documentation <http://www.povray.org/documentation/view/3.6.1/246/> but it
> doesn't seem to mention any about defining a focal length and principal point.
> any tips?
> 
> thank you
> 
> regards 6digit
> 

The length of the direction vector determine the distance between the 
camera and the projection plane. In a way, it can be seen as the focal 
length of the camera.Then, the ratio between the up and right vectors 
determine the aspect ratio of the image. Those three vectors should be 
perpendicular to one another.

If you want to emulate focal blurring, then, you need to use the focal 
blur feature. For that, you need to also define the aperture of the 
emulated objective, the focal point and how many samples are to be used.
You will find the relevant information here :
https://wiki.povray.org/content/Documentation:Tutorial_Section_2.2#Using_Focal_Blur

Hope that it's useful to you.
Happy POVing.


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From: jr
Subject: Re: how to define the focal length and the principal point of a camera in p=
Date: 18 Jul 2022 11:55:00
Message: <web.62d5814b9be596051be3cd4b6cde94f1@news.povray.org>
hi,

Alain Martel <kua### [at] videotronca> wrote:

> > ...

just to add, I find Google searches prefixed with 'site' usually gets me good
results, so the below was the second "hit" when searching:
  "site: news.povray.org focal length"

<http://news.povray.org/povray.general/message/%3C43672159%241%40news.povray.org%3E/#%3C43672159%241%40news.povray.org%
3E>


regards, jr.


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From: Thomas de Groot
Subject: Re: how to define the focal length and the principal point of a camera in pov r=
Date: 19 Jul 2022 07:51:07
Message: <62d69aab$1@news.povray.org>
Op 18-7-2022 om 15:29 schreef 6digit:
> good evening,
> 
> I recently calibrated a camera to get the intrinsic and extrinsic parameters. my
> main goal is to mimic the perspective camera in pov ray with that of the real
> one. I was wondering if it's possible to define the focal length and principal
> point of the perspective camera located in pov ray. I read through this
> documentation <http://www.povray.org/documentation/view/3.6.1/246/> but it
> doesn't seem to mention any about defining a focal length and principal point.
> any tips?
> 
> thank you
> 
> regards 6digit
> 

This has been done in the past by Edouard Poor in 2009. Go to:
https://news.povray.org/povray.binaries.images/thread/%3C528023d4%40news.povray.org%3E/

-- 
Thomas


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