3D Glasses, How Do They Work?

[Santa Clarita Len]

Today we went to the movies and saw G Force with 3D glasses and once again I wondered how do they work. What makes the image look 3D. They do a great job but can someone explain in layman's terms how they transform the image.

[Bill in Buena Park]

Len,
Two images recorded in stereo photography simulating human binocular vision, projected through polarizing filters on the same screen, and the 3D glasses have polarizing filters that allow only one image to be seen by each eye.

See this for 3D polarized images - http://en.wikipedia.org/wiki/Polarized_3D_glasses

See this for stereo photography - http://en.wikipedia.org/wiki/Stereo_camera

[Tom Slick]

Here is the long explaination:

http://www.howstuffworks.com/question360.htm

[Santa Clarita Len]

Thanks guys, although I wouldn't be able to explain it to anyone I now have somewhat of an understanding of how 3D works.

[dlminehart]

I wanna know how those xray glasses on the backs of old comics worked!

[BobSch]

I wanna know how those xray glasses on the backs of old comics worked!

Not very well!

[drumpriest]

The current 3D glasses for movies are rotational polariziation, but certainly not the only method. Linear polarization has been around for a while, and it's what some of the Disney attractions use, you can tell because if you tilt your head, the 3D goes wonky. With rotational polarization this isn't an issue.

These are "passive" systems, in that the method for isolating eyes is done at time of projection, there are "active" systems such as LCD shutter glasses, but of course these are not practical for movie style applications.

Pretty neat stuff, really. My last project was a 3D project, so I have to know this stuff.

[JSUPreston]

Alas, a technology that I will never be able to use. Due to a birth defect that was easily correctable (but not affordable-parents were dirt poor), I have 20/200 vision corrected in my left eye, and a blind spot pretty much dead center of the eye. Straining to use my peripheral vision, I sometimes can make out shapes at a distance of 3 feet. Without glasses, my left eye is off the chart low. My "good" eye is 20/20 with glasses, and 20/200 without, so without glasses I am legally blind and find it nearly impossible to do anything. People have actually asked me how I got a drivers license and how many accidents I've had.

Last time I tried the 3D glasses, I was at the aquarium in NOLA before Katrina. I could tell immediately things weren't going well. I was so sick to my stomach that about 1/2 way through the movie, I had to take the glasses off and close my eyes. By the time it was all over, I had the 2nd worse migraine of my life. Took days and lots of medicine to get over it.

I sometimes envy you guys with the 3D movies, but it gives me the perfect reason not to take the kids to those movies. Until they can plug directly into my skull, 3D movies will never happen for me.

BTW: My eye doctor tells me that an eye transplant wouldn't help at this point either, the optic nerve has atrophied over the years and would never recover. Needless to say, eye protection is a must for me.