P3D Re: What is the "Stereo-Base"?

[michaelk@xxxxxxxxxxx (Michael Kersenbrock)]

> What is the "stereo-Base"?
> Some people would say: 65mm, like the distance between the
> eyes. 

The baseline the formula below calculates for a near-point of 7 feet
and the typical realist camera focal length works out to about 65mm.

> And some would say: 1/30 from the mearest object.
> *Rubbish* - Those answers is good for amateurs!
> I found this formula provided by David Kuntz in the ISU STEREOSCOPY:
> 
> i   *   b  
> ----------     =    n
>     p
> 
> i = focal length, in mm.
> b = baseline, in feet.
> p = parallax (1.2 mm for infinity far point)
> n = near point, in feet.
> 
> And I have got some q. about this formula:
> A. What "parallax" is?

I'm not going to *touch* the 1.2mm number.  See past
postings in tech-3d (as well as how to calculate things,
including spreadsheet programs).  :-)

> B. Here in Israel we use the "Metric System"
>     How can I use the formula only meters & cm?

Change the units for 'b' and 'n' to anything you want,
as long as they are the same.  meters would work.

Likewise, you can change the units for 'i' and 'p' to anything
you want so long as you use the same units.

Without changing the formulae.

> C. I know the near point, and I want to calculate
>    the "base-line" - How can I do that?


b = ( n * p )
    ---------
        i


Assuming your formula is applicable to your application.  :-)


Mike K.

> 
> Thanks,
> David B.
> Tel-Aviv
> Israel.
> 
> 


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