1. Ng Boon Hian Physics behind 3D Movies

2. Case Study – 3D movies With 3D viewing technology offered in cinemas, many people are fast to snap up on the tickets to 3D movies. I watched Alice in Wonderland in 3D version at Shaw Theatre recently and wondered what was the science behind the 3D glasses.

3. How do our eyes work Our eyes project a 3D image in the brain by seeing things from two different viewpoints as noted by the gap between our eyes and these 2 2D images are formed in the brain into 1 3D image. Thus, 3D images are formed and everything in the real world is 3D.

4. 2D Movies 2D movies work on a film being projected onto the screen. Everything is on the screen and in 2D. The light is unpolarized.

5. Polarized light and Unpolarized ight Light is an electromagnetic wave Electromagnetic waves consist of electric and magnetic component Electric component (electric force field) moves up and down as the electromagnetic waves forward

6. Unpolarized light From Sun, bulbs, candles No fixed plant of oscillation Yellow plane arrow changes angles but keeps direction of light Random changes in direction of light 3D animation

7. Polarized Light Filtered Light Fixed plane of oscillation Half of the intensity of unpolarized light

8. Unpolarized VS Polarized For unpolarized light, no matter how the arrow turns, electric forces are always perpendicular to ray direction Polarized lightUnpolarized light

9. Polarizers Filters out the unpolarized light into single light planes Have lines aligned in 1 direction and only allow 1 plane of light to pass Circular polarization and linear polarization

10. Circular polarizer and linear polarizer Circular polarizer used for 3D glasses

11. Circular polarizer and linear polarizer Circular polarizer is just a quarter wave plate in addition to the linear polarizer Linear polarized 3D glasses will work with all the old stereo projectors, StereoJet prints, and modern projector systems with linear polarizers attached Circular polarized 3D glasses are specifically for the StereoGraphics Z-Screen and some 3-D digital projection systems.

12. Circular polarizer and linear polarizer Not much difference as both saturates colors and eliminates reflections from water and windows for cameras Circular polarizers are more expensive but can eliminate possible metering errors while linear polarizers are unable to

13. Filters to transform unpolarized light to polarized light Polaroid filter Enables only 1 polarization of light to pass through.

14. 3D Movies Eyes are two inches apart, two different angles on viewing the same things creates a 3D image 3D movies trick the brain by projecting two 2D images separately to the two eyes and recreate a 3D image in the brain

15. 3D Movies 3D movies not viewed with the glasses are very fuzzy and eye-straining to look at The same scene is projected simultaneously from two sources Previous 3D movies used colour as filter but polarization is used

16. Colour and Polarization Colour 3D uses contrast of colours An anaglyph image is formed Each lens is made up of a chromatically different colour – blue and red Colour used to provide separation Red part allows blue light to enter while blue part allows red light to enter

17. Colour as filter A severe disadvantage is that film cannot have much colour as colour is used as filter in this case Stereo Monochrome image

18. Polarization Two synchronised projectors project two respective views, each with a different polarization Each side of the glasses allows 1 plane of light to enter

19. 3D Movies Due to the 3D effect, viewers can feel the thrill of being in the movie themselves and get really close to the characters

20. Bites 3D glasses if not cleaned properly can pass on eye infections to others Can cause headaches and blurred vision Forces viewers to focus on things in the foreground (which causes eyes to converge) and distance (which causes them to separate) simultaneously Vergence accomodation conflict

21. Build your own 3D glasses activity Cardboard Scissors Tape Red and Blue acetate (Available from art store)

22. Build your own 3D glasses activity Trace a pattern on the paper of the three parts of spec mainly the two sides and a middle portion Place them on the cardboard and cut out the shapes Cut eyeholes Tape the blue and red acetate separately on the two eyeholes and you have a 3D glasses

23. Other Facts 3D glasses used will not produce a 3D effect on home TV as light is unpolarized

24. Thank you! http://www.colorado.edu/physics/2000/polarization/polarizationII.html http://www.physicsclassroom.com/class/light/U12l1e.cfm http://science.hq.nasa.gov/kids/imagers/ems/waves2.html http://library.thinkquest.org/C006027/html-ver/op-polar.html www.wikipedia.com www.google.com http://www.3dglassesonline.com/how-do-3d-glasses-work/ http://www.howstuffworks.com/3dgraphics.htm http://www.bobatkins.com/photography/technical/polarizers.html http://www.berezin.com/3D/3dglasses.htm http://www.articlesnatch.com/Article/Difference-Between-2d-And-3d- Animation/921882 http://stereo.gsfc.nasa.gov/classroom/glasses.shtml http://wiki.answers.com/Q/Why_do_Real_D_3D_glasses_work_in_the_cinema_but _they_wont_work_with_any_other_3D_images_at_home_Are_there_any_images_tha t_do_work