3D-viewing (Updated 19th. of May, 2011)
 

There are several methods available to show 3D-images. Depending on the media, size of your audience and what kind of invironment you are into they all have their advantages and disadvantages. Below is a description of the most used methods, but not all and probably more will show up in the future.

Polarized Projection: The most suitable method for displaying 3D images for a larger audience is with no doubt by "Polarized projection". That's also the reason why I use this method when I keep my lectures. A technique which requires glasses (Which I provide) but also provides minimal color loss and minimal "Ghosting" (Shadows where the contrast and diversion in the images is high) ..... yes indeed it is the same technique as the majority of the digital 3D cinemas are using today.

To get the polarization to work it is necessary to show the images on a silverscreen. Using a white screen will simply result in no 3D-effect at all.

The disadvantage of this method is primarily related to economy. Relatively high prices on beamers/projectors is still an isue, but prices has dropped down considerable in the recent years and the technical development still increase quality. From a logistic point of view, it also takes plenty of place in the car to travel with a dual beamer setup and a desktop computer to connect it all together.

 

 

3D-projector consisting of two BenQ W6000 FULL HD beamers and a desktop computer. Notice the polarized filters in front of each optic.

 

Aanaglyph: The method is used with 2 colored glasses (Each glass with chromatically opposite color, usually red (Left) and cyan (right)). Usually the main subject is in the center of the image as foreground and background displaced laterally in opposite directions. When viewed through the red and cyan colered glasses the images appears with a certain depth, also called 3D.

Advantages: Easy accessible as the method works with all kind of media (Paper, TV, movies, web, etc.) and can be viewed by anyone who has their vision intact in both eyes. A pair of anaglyph glasses can usually be purchased for less than 3,- Euros.

The disadvantages is mainly a relatively large loss of color and so called "Ghosting".

3D-image in "Anaglyph".

   

 

LCD Shutter: In 3D-TV and computers the "LCD Shutter method" has became widespread in recent years. An electronic signal that provides the glasses alternately opens and closes the view of each eye, depending on whether it is the right or the left image that is displayed on the screen. Since it all happens very quickly (typically at 120 Hz) we perceived the two images as one 3D image. The main advantages of this method is a low loss of color and very little "Ghosting" and the method can be used with both LCD-screens and projectors (If prepared for 3D.). When both left and right image are displayed on the same screen / projector the 3D-image may appear slightly dark, especially at the cheaper ends of monitors / projectors that are not so bright. Furthermore, the glasses are still pretty costly (From about 70 - Euros/ pair in 2011) since they contain a certain amount of electronics which is runing on a battery.

3D-computer monitor with "LCD shutter-glasses". Notice the indared transmitter that gives the signal to the glasses shutter-function...

 

   

Digital 3D display: By using a stereoscopic mirror and two 10" digital pictureframes I managed to make a small portable 3D-viewer which can be used wherever there is power from an electrical outlet available. The memory cards in the digital frames can contain several thousand images which can be viewed in 3D through a pair of polarized glasses.

The light from the LCD-pictureframes is already polarized so the use of polarizing filters isn't necessary. You only need polarized glasses to view the images in 3D. To separate the polarized images to each eye, one of the digital picture frames are placed over the other at an angle of approximately 110degrees. One screen is turned upside down to get the polarization opposite to the second screen / the other eye. The stereoscopic mirror is then placed between the screens so that one picture is thrown up on the underside of the mirror and the second image (which must be inverted) is thrown onto the front of the mirror and by using the polarized glasses each eye will see it's own picture and appear in 3D

Advantages: Very nice experience and the 3D-effect is in top quality with no or very little ghosting. You might be able to build a stereo/3D-display yourself.
Depending on the screen size the pictures can be shown to a small group of people at the same time.
Disadvantages: Relatively expensive if you can't build it yourself. Unless using digital picture frames, but computer LCD-monitors instead, your computer must also be able to handle two LCD-monitors, in example by Dual DVI output on the graphic card.

10" Transportable 3D-display in funktion
Photo by Peter Randløv

 

 

 


Cross-eye view: The absolute cheapest and simplest method to view 3D images is by "Cross-eye viewing". In all its simplicity it's all about having the right image to the left and the left image to the right, side by side. By observing the images on "Cross", by viewing the left image with your right eye and the right image with your left eye, you will see a 3rd. picture between the other two images. This image will appear in 3D, completely clear and without color loss. This viewing technique requires some practice, and many never learn it, which to be said this methods main disadvantage.

 

 

3D-image for "Cross-eye view".
   


Parallel: In the first place this method looks like the "Cross-eye method" but here you are looking at the left image with your left eye and the right image with your right eye.

Advantages: No loss of color and the 3D-effect is working fine. The main disadvantage is that most people will need special glasses (Pokeskope viewer or so-called lorgnetts) to see the images properly. The images may not be too large and a good pokeskope viewer is relatively expensive compared with lorgnetts that can be difficult for some people to use. Because of this, the method is not suitable for viewing for more than a single viewer at a time.

 

3D-image for "Parallel view".