Seeing in 3D by closing one eye

[williams2]

3D

Most video files contain much 3D information builtin.

The brain is smart enough to see (using 2 eyes)
that the television or computer monitor is a flat screen
and so shows the picture as a flat picture without 3D processing.

If the brain is tricked into not seeing the picture as a flat picture,
ir looks like a 3D picture to the brain (because it is)
and processes it using the 3D information which is included with the picture.

One way of tricking the brain into processing the video pictures as 3D
is to close one eye.

There are also diseases that can affect how easy it is to see the 3D processed video.

See https://en.wikipedia.org/wiki/Pulfrich_effect
The Pulfrich effect may or may not exist,
but when you watch any video with one eye partially or completely blocked,
you are simply tricking the brain into processing the video
as 3D using the builtin 3D information..

It works with any video, colour or BW, moving or still pictures.
It does not need special glasses or equipment.
It does not change the colours (like anaglyph)
It does not need special 3D films to watch.
It works quite well with most videos and also still pictures.

[amethyst]

Don't know if related but you get these 3D images, that if you concentrate on it you should see the 3d images or pattern appear (come to the fore). I'm not so good at this but some people see these 3D stuff come to the fore immediately when they look at the picture. I normally see it after a while of concentrating on the image and in most cases I see it quicker with a sort of deliberate double vision focus. Distance from the image also plays a big role for me.

[6502coder]

You mean stereograms? The ones where you have to look at the picture slightly cross-eyed in order for the 3D image to appear? As I recall there was a brief time in the early 90s when they became something of a fad. There were books of them, and there was even software you could buy to make your own stereograms. I was one of the lucky folks who could see the 3D image almost instantly.

But the OP is about something else entirely.

This sounds like the 3D effect I experience when I close one eye while watching TV. It works best when the image is simple, and -- at least for me -- it mostly involves getting the distinct impression that the picture is "layered," with certain elements appearing to be in front of others. I vaguely remember reading an academic paper on the phenomenon back when I was a college student studying optics.

As williams2 implies, I believe what's going is that the brain "knows" that the overlapping of objects is an indication of relative distance: the things that are closer will block out parts of the things behind them. Similarly, when two objects have the same actual size, the closer one will appear larger. When you watch TV with both eyes, your stereo vision sees only a flat image. But with only one eye, the brain can't triangulate distance, so it falls back on principles like overlap and relative size to deduce distance.

However, I believe this is somewhat different from the cited Pulfrich effect, which involves MOTION. Quoting the Wikipedia article: "...the Pulfrich effect depends on motion in a particular direction to instigate the illusion of depth."

[williams2]

The matrix screen saver has 3D information built in.

Code: Select all

xlock -nolock -mode matrix

Motion, even very small amounts of motion,
can be processed by the brain to show you the 3D information built into the video.
So yes, motion, even a small amount of motion,
enables the brain to process the 3D information.
Almost every film, television program, etc has at least small amounts of motion that the directors think adds interest to the video, which it does, because it adds 3D information that the brain can process and help you to see, for example, hidden tigers hiding in the bushes.