How 3D Works on a 3D TV

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hi this is Sean for howdini today we're

gonna talk about how 3d television works

to find out we went to Los Angeles to

talk to this man my name is Perry

Hoberman he teaches at a School of

Cinematic Arts at USC and he's an expert

in immersive technologies like 3d and

virtual reality we asked him all about

how 3d works the first thing we learned

is movies and TV look 3d because they're

shot with two lenses cameras kind of

substitute for your eyes right if you

just think of two cameras or two lenses

where your eyes are each taking a

picture one is seeing the image slightly

from the left one from the right then if

you present those images one to the left

eye one to the right eye your brain

fuses them together to create the

impression of three-dimensional shapes

and surface and a hard part is to show

these two separate images to an audience

there's two basic ways to do this the

first is called stereoscopy it's a side

by side configuration so it's one image

and then another image okay and this eye

looks at this image this eye looks at

this image you've got a 3d image one

tiny little problem problem with side by

side is it's for single it's for a

single view not ideal for a movie

theater next option overlap the images

when you overlap the images you

basically project them on top of each


and now the problem is we have to figure

out some way that we can screen out this

image for the left eye on screen out

this image for the right eye this is

where the glasses come in they filter

the images to only show one image to

each in the 50s and 60s movie theaters

use two projectors to overlap the images

and this caused a few problems problem

within the 1950s was they used two

projectors that were interlocked so they

were supposed to go together but film is

a fragile medium and if the projectors

got one frame out of saying he's out of

sync images would not fuse together in

your brain the right way and along comes

digital digital cinema is in fact I

think the thing that made 3d turned it

into a process that was repeatable and

dependable and you could really show

films in a way that they weren't going

to be those kinds of problems this

digital image is consistent and reliable

and each image is filtered in a special

way switching the polarization of the

lights so that the left image comes out

polarized one way the right image then

follows polarize the other way you wear

the glasses with two different kinds of

lenses to match the polarization of each

image one image for the left eye one

image for the right eye and voila

can now watch a 3d movie at home just

like you do in a movie theater thanks to

Professor Perry Hoberman for talking to

us we made a video about 3d glasses you

can watch it here and for more tips and

information or to see the rest of our

interviews please check out the website