[photo-3d] Re: do you believe it?

["Kenneth J. Dunkley" <KenDunkley@xxxxxxx>]

--- In photo-3d@xxxxxxxxxxx, "John A. Rupkalvis" <stereoscope@xxxx> 
wrote:
> Yes, stereoscopic vision does require two different images.   The 
brain
> compares difference information and interprets this as depth.
> 
> However, there are many ways of encoding difference information in a
> picture.

Hi John,

Your full comments reproduced below, mirror the comments of the 
majority of individuals who have attempted to explain the 3-DVG 
effect on this list. 

Your comments are wide ranging and you state at the outset, "Yes, 
stereoscopic vision does require two different images."  

If you want to "define" stereoscopic vision as that requiring two 
images, then we have no argument. I would certainly agree with you.  

But definitions have little to do with objective observable reality. 
The question really is: what might you have observed if you took the 
time and attempted to detect the effect. Chances are you would have 
observed that a single picture can indeed appear unequivocally and 
undeniably stereoscopic albeit less stereopsis than that created from 
stereo pairs (at a camera separation of 65 mm).  Since stereo 
disparity (i.e., stereopsis) depends on the camera separation, if we 
use less or more separation than the normal 65 mm, we will perceive 
less stereopsis or hyperstereopsis in the final stereo image.

But now, we have an interesting situation, if we call it false, are 
we saying that what we see does not possess the visual properties of 
a stereoscopic picture (albeit less stereopsis)? or that it is not 
identical to stereo pairs. Clearly, it is not identical to stereo 
pairs, but is it undeniably stereoscopic. 

I have chosen to call it the 3-DVG effect and by doing so I believe I 
have separated it from normal viewing by stereo pairs. I tend to 
think you feel otherwise, that is your call. I only ask that you 
attempt to experience it before you identify with the process you 
identify as "False Stereo". I do not believe it is directly related 
to that because the 3-DVG effect can be detected in black and white 
images.

Hey, I'm not trying to replace stereo pairs here! The 3-DVG effect is 
a phenomenon that will expand your perception and appreciation of 
pictures and vision science in general. Trust me on that.  

Your remaining comments are very familiar, I too held a similar point 
of view for a period of time. I soon realized a theory based mostly 
on pictorial cues (what you call monoscopic depth cues), or on 
chromostereopsis (ala ChromaDepth) was insufficient to explain my 
observations. 

The following is a partial list of the visual properties of the 3-DVG 
effect; these observations changed my mind and can be verified in a 
matter of minutes with a copy of National Geo in hand:

(1) The 3-DVG stereoscopic perception of an object's relative visual 
depth within a scene is independent of the color of the object.

This can be confirmed by viewing two pictures containing objects of 
different colors but with the object's relative distances reversed.  
However, note that if the 3-DVG device is operated outside of its 
normal operating range, pinhole generated chromostereopsis will begin 
to predominate (as you indicated). At this point, red colored objects 
will no longer maintain their relative position within a visual scene 
and will literally, pop off the page. Blue objects will tend to 
recede (also as you indicated).

(2) The 3-DVG effect can be observed in black and white photographs, 
and also in monochrome photographs. Note that the ease of detection 
is much reduced. I missed it the first time I looked. (For the 
record, note that even a black and white photo contains spectral 
colors covering the entire visual bandwidth. But, each individual 
picture element/object will possess approximately the same spectral 
bandwidth)

(3) The 3-DVG effect can clear up ambiguous photographs such as a 
photo of splashed water, pictures of ambiguous white mountain top 
snow, or murky underwater photos. 

(4) The 3-DVG effect actually adds objective visual information to a 
scene. Unobserved or unnoticed details in a scene suddenly become 
apparent.  

Confirm items(3) & (4) by simply going through an issue of National 
Geographic cover to cover.


(5) If you have a picture of a stick or other long object being 
pointed at the camera taking the original picture, then the stick can 
appear to actually project forward out from the plane of the picture. 
You will be able to place a test object on the surface of the picture 
and demonstrate that the stick actually projects towards the viewer. 
In other words, the image of the stick will appear closer to you than 
the test object resting on the picture. 

(6) The 3-DVG increases the observed picture resolution and the 
observed contrast in a picture. Using the 3-DVG can feel like you are 
seeing photos for the first time. At moments, it can feel like your 
mind is actually receiving and processing more information. 

(7) The 3-DVG effect is in no way limited to scenic pictures, its 
effects can be detected on ANY picture. It is just that if you are 
new to the process, scenic pictures are easiest to observe.

(8) The 3-DVG process does not work in movie theaters or under 
outdoor lighting conditions.

John, I wrote an explanation of the 3-DVG effect in my SPIE paper, "A 
new 3-D from 2-D visual display process," SPIE, Vol. 1915 
Stereoscopic Displays and Application IV (1993) pp. 132 -140. The 
visual properties of the 3-DVG rest on four distinct visual effects, 
the most interesting being the Adelbert Ames Jr. principle of 
stereoscopic generation by alteration of the interoptic viewing axes. 
Unfortunately, few people have bothered read it|:-). 

John, if you're interested that pinhole offer still stands. Let me 
know by email if you'd like to receive them. 

Best regards,

Ken Dunkley

http://www.3-dvg.com   Make any picture 3-D using only your fingers.

http://www.3-dvg.com/thoughts  Arguably, the most stunning 3-D image 
ever created


--- In photo-3d@xxxxxxxxxxx, "John A. Rupkalvis" <stereoscope@xxxx> 
wrote:
> Yes, stereoscopic vision does require two different images.   The 
brain
> compares difference information and interprets this as depth.
> 
> However, there are many ways of encoding difference information in a
> picture.
> 
> This can be true stereoscopic as with an anaglyph or a Pulfrich (or 
other
> time parallax type image), or it can be "false 3D", which are 
simply images
> that give the impression of depth, buf the depth is not encoded in 
a manner
> such that it simulates the actual depth relationships of the 
original scene.
> An example is the chromatic systems, such as the one that involves
> diffraction grating grids that spread light in proportion to 
wavelength,
> yielding a wavelength, or color hue differentiation (ChromaDepth).
> 
> Although I have not had time to check out the pinhole method, I 
would guess
> that this is a related effect.
> 
> Since a very small aperture increases depth of field, these would 
allow
> image information to be resolved on the rods in the retina, where 
this
> information is normally too diffuse to be interpreted as sharp image
> elements.
> 
> If the monochrome image information, which is displaced from the
> trichromatic (received by the cones), it is likely that this will 
also
> result in chromatic difference information that the brain 
interprets as
> depth.
> 
> Although this would be classified as "false 3D" like other depth 
signals
> that are not keyed by real depth information in the subject, the 
results (as
> with ChromaDepth) under the right circumstances can appear quite 
convincing.
> 
> The reason for this is a rather convenient visual coincidence 
involving a
> common monoscopic depth cue.  In many (but not all) situations in 
real life,
> warm colored subjects (people, red, orange, yellow, tan, gold, etc. 
colored
> objects) just happen to be in the foreground, while cool colored 
backgrounds
> (grass, trees, sky, distant mountains, etc.) are farther away.  
This can
> give a sometimes rather convincing appearance to chromatic 
differentiation
> systems.
> 
> Of course, this can also backfire and produce rather wierd, 
sometimes even
> amusing, false depth effects when the colors are not arranged in a 
logical
> sequence for the effect.  An example would be a person in a red 
shirt with
> blue slacks.  The top half of their body would appear to float out 
in front
> of the bottom half.  Actually, it might work with Dolly Parton...
> 
> JR
> 
> ----- Original Message -----
> From: "Herbert C Maxey" <bmaxey1@xxxx>
> To: <photo-3d@xxxxxxxxxxx>
> Sent: Sunday, October 15, 2000 1:09 PM
> Subject: Re: [photo-3d] Re: do you believe it?
> 
> 
> > >>>Make any picture 3-D using only your fingers.
> >
> > By happenstance, I was thumbing through the current "Discover" 
Magazine;
> > at least I think it was that one, and I came across a few example 
of
> > colored circles. The short filler was about seeing "False 3D". I 
am not
> > an expert, but since there is an apparent thing called False 3D, 
perhaps
> > the above might also fool the brain. The brain can be fooled in 
many way,
> > as can hearing.
> >
> > You can't make any picture 3D (Stereoscopic). There is no 
possible way.
> > What is being demonstrated is some other visual artifact. 
Stereoscopic
> > Vision requires 2 different views.
> >
> > Bob
> >
> >
> >
> >