P3D Re: PHOTO-3D digest 3135

[Ray Hannisian <ray@xxxxxxx>]

Dana Nibby wrote:

>I vaguely remember reading somewhere about a device used to convert an
>ordinary camcorder into a 3-D camcorder by splitting the lens.

While splitters can be used, most currently produced 3D video is in the
"field-sequential" format.

NTSC (the US and Japanese standard) video consists of 30 frames per second,
(PAL is 25 fps).  Each frame is made up of two "fields", on the odd and
even horizontal scan lines.  These "fields" are "interlaced", although the
information in each field comes a 60th of a second after the other.

An advantage of "field-sequential" video over anaglyph, is that full color
images are available.  Unlike "Pulfrich", even still images may be
precisely placed in front of, at, or behing the screen.  And, unlike "split
screen images, full size pictures, using the entire screen, are possible.

A disadvantage of this format is "flicker", and the fact that each eye sees
only half the vertical resolution of a normal video picture.  Many schemes
have been and are being developed to solve these problems.

>How much do real 3-D camcorders cost?

Several years ago, Toshibe made a consumer stereoscopic VHS-C camcorder.
As only about 500 to 800 were made, any you can now find are being sold at
outrageous prices, (often $8,000 to $12,000).  The NU-VIEW camcorder
attachment is an inexpensive solution, although it has the limitations of a
fixed, reduced stereo base, reflection and alignment difficulties, and
uneven light transmission between the left and right views.

>Also, are most 3-D video tapes compatible with different kinds of signal
boxes/shutter glasses?

Most of the shutter glasses on the market are compatible with most
"field-sequential" videos.  However, the decoder box must be video
compatible.  (Some are designed for computer use only.)

In general, it is possible for "field-sequential" videos to be made in
"left or right eye first" field assignments.  Decoder boxes from Ray3D
(APEC), VREX and NU-VIEW (3D Video, INC.) have buttons or switches to
adjust for these preferences.  Virtual i/o "i-glasses" also have "3D-1" and
"3D-2" settings to accomodate these circumstances.

For a list of compatible systems and available content, visit my web-site at:
		http://www.ray3d.com/video.html

Sincerely,


Ray Hannisian

   ====== Ray 3D - Stereoscopic Imaging ======
                  ray@xxxxxxxxx
              http://www.ray3d.com

                 (970) 963-8474



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