The 3D Cinema Experience at Home

By Eric James


I love going to the movies. Always have and always will. Since 3D movies have become all the rage I enjoy it even more now. I don't need much excuse to go and experience the wonders of the fantastic new effects that 3D promises. 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.

Because our eyes are separated slightly they each see the world from a different perspective. 3D movies mimic this effect thus giving the illusion of depth 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

Firstly, let's get the anaglyph method out of the way. If you've never heard the term before I am referring to the red and blue glasses that are usually manufactured from cheap cardboard with low grade plastic lenses. Each separate image is made up of either a red or blue tint. Your eyes have the corresponding image filtered out by the colored lenses thus allowing each eye to see only one image each. This technique suffers from muted colors and blurriness so has never really been used for feature length movies.

Active Shutter Glasses Stereoscopy

Active shutter glasses use a method that is technically known as alternate-frame sequencing. Each eye has its view blocked by the lens going dark when the image that it is not supposed to be seeing is on the screen. This is the reason a TV needs to be capable of at least a frequency of 120Hz. Divide this by two and you have the required 60Hz for each eye that is needed for smooth animation. Even higher frequencies can ensure a flicker free experience for the vast majority of viewers. These higher frequencies are becoming the default standard of new model TVs and projectors.

Active shutter glasses have a couple of disadvantages. Perhaps the biggest disadvantage is the need for a power source for the glasses. It can be provided via cable tethered to a power supply or via 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. As they have been around for a while now prices for active shutter glasses and the TVs that use them have greatly reduced in price. If you only need one or two pairs of glasses then this would be the way to go.

Polarized Light Stereoscopy

Technological research has created new ways of displaying 3D imagery in the home. Polarized light stereoscopy, currently popular in cinemas, is now being made available in the home marketplace through the use of projectors. It's a very efficient way of creating 3D images as both images can now be displayed on the screen at the same time. 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. The images are projected so you will also need to buy a silver screen to get the best effect. A silver screen is needed to keep the light polarized so the image remains crisp and clear.

The polarized technique has some major advantages that will enable it to become the dominant method when prices finally do come down. Glasses are easier to manufacture and are lots cheaper and lighter than shutter glasses. You can also have a more widely dispersed audience as the 3D effect is viewable from more angles. The average pair of shutter glasses will darken the image by about 20%. You get a much brighter image with polarized lenses as they only block about 10% of the light.

The author loves electronic gadgets and loves writing about his passion. You can find more information on home entertainment technology on his site at 3D projectors for the home theater




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