Re: [photo-3d] 1/30 rule for video!?

[Owen Pearn <owenp@xxxxxxxxxxxxxx>]

as far as i've been able to determine from the human factors literature
and my own experiments, the maximum deviation is related to angular
disparity created at the eye.

by trignometry, this means that viewing distance is the driving
parameter.

lenny lipton recommends a maximum of 1.5 degrees of uncrossed parallax
(behind the presentation plane). note that it seems as though humans in
general can tolerate a little more than that of crossed parallax (in
front of the presentation plane) but i use 1.5 degrees for both.

if my math hasn't failed me, the relation is: 

  maximum deviation at the presentation plane allowed at a given viewing
distance = the viewing distance * 0.02618

and conversely:

  minimum viewing distance for a given deviation at the presentation
plane = the deviation * 38.2

i usually round up to 40 when i'm doing these calculations in my head:

  deviation = distance / 40
  distance = deviation * 40

as a starting point for more info, i recommend:

  http://www.stereographics.com/html/chapter_2.html

-o-

boris@xxxxxxxxxxxx wrote:
> 
> Sergio Baldissara wrote to the glamourphoto group:
> 
> >Sorry for my (perhaps non pertinent) intrusion... can I know what videos
> >you're talking about and what stereo method was employed?
> ...
> >THE MAXIMAL DEVIATION BETWEEN 2 MATCHING POINTS SHOULD NOT BE GREATER THAN
> >1/30 OF BASE (HORIZONTAL SIDE) OF THE FRAME (or screen.. say 2° parallax)
> >anyway if you want formulas...  http://home.mira.net/~kiewavly/bases.html ;
> >is it possible the movie-makers ignored such simple rules?
> 
> Harold Baize was talking about videos using frame alternate format.  But I
> believe the discussion related to anaglyph as well.
> 
> Sergio, not another rule flattening out what might have been good depth
> pictures?  1/30 sound too small!  On my monitor, which is 30cm wide, you
> are recommending a deviation of no more than one centimeter.
> 
> Is the recommendation for this maximum deviation based on any physiological
> principles?  Does the fact that motion will be shown recommend the use of
> smaller deviations in a picture?
> 
> I would think that for video, because of its lower resolution, more
> deviation would be necessary for a reasonable range of depth to be
> apparent.
> 
> Boris
> 
> - Science is the part of culture that rubs against the world.
> -
> -                                     Stanislaw Lem, _His Master's Voice_
> 
> Boris Starosta                        boris@xxxxxxxxxxxx
> Stereoscopic Art & 3-D Photography    http://www.starosta.com
> usa - 804 979 3930                    http://www.starosta.com/3dshowcase



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