I love going to the movies. I don’t think I’ll ever get sick of it. Now that we have 3D movies I’m like a little kid in a candy store. You don’t have to twist my arm to get me to experience the joys of a well made 3D experience. Fortunately I have four little girls who also like an outing to the movie theater and enjoy a good 3D film as much as the next person and not just movies made for girls either.
3D movies work by making sure each eye sees a different image to the other, both taken from a slightly different perspective.
As each eye perceives the world from a slightly different perspective due to them being about 2 inches apart this effectively mimics the way we see the real world and creates a more realistic 3D image on a 2D screen. Every 3D image or movie you view uses this same principle but may go about it in a slightly different manner.
Anaglyph Stereo
Once a popular method anaglyph is now more of a novelty due to its poor picture quality. In case you don’t know the term anaglyph refers to the red and blue glasses which are usually made out of cardboard. The two separate images for the eye are created with either a red or a blue tint. The red or blue lenses filter out the corresponding image so each eye sees the different perspective. This technique is a novelty at best and is not really suitable for enjoying 3D movies in high definition full color.
Active Shutter Glasses Stereoscopy
Active shutter glasses use a method that is technically known as alternate-frame sequencing. Each image is shown alternately on the screen. When an eye is not supposed to see the image it is blocked by the shutter over that eye going dark. When the technology was fairly new many people complained of a visible flickering in the image. It’s for this reason that a TV needs to be have a refresh frequency of 120Hz or higher to double the frame rate of the animation on screen. These higher frequencies are becoming the default standard of new model TVs and projectors.
Active shutter glasses have a couple of disadvantages. The major disadvantage is that the glasses require power either through a cord or from batteries. If you are blessed with a large family you are either going to create a jungle of cables or you will have a rather large expense for batteries. The major advantage is that the technology has been around for a while now and projectors and TVs using this method are relatively cheap. If you only need one or two pairs of glasses then this would be the way to go.
Polarized Light Stereoscopy
As technology is always evolving new techniques for displaying 3D imagery are coming onto the market. One such system uses polarized light for projecting images onto a screen and it is now possible to display both images on the screen simultaneously. Special polarized lenses in the glasses are polarized to only let in the correct image while blocking the other.
The major disadvantage of this method is the cost. It’s new technology so prices are still quite high. Another disadvantage is that you will need to buy a silver screen to get the best viewing experience. Silver screens make sure the light reaching your eyes remains polarized so the picture retains its quality.
I believe polarized light stereoscopy will become the dominant method of 3D in the home eventually as costs decrease over time. The glasses are lighter, cheaper and don’t require batteries. You can also have a more widely dispersed audience as the 3D effect is viewable from more angles. Shutter glasses also have a tendency to darken the image by about 20%. Polarized lenses give you a much brighter image by only blocking out about 10%.
This article has been written by the author, Alex Blaken. Should you require any more 3D Cinema please visit his 3D Movies resources!