How 3D TVs Work


How 3D TV works – 3D TV Technology


As with all 3D programmes, the action is captures using TWO cameras, effectively mimicking the two human eyes.

Rather than transmitting a single colour-coded signal, these 3D TV sets display two sets of signals, one for the left eye and one for the right eye. The difference lies in the way your eyes are fooled into seeing the two views separately:

Lenticular viewing: These 3-D sets are meant to be watched without any funny glasses. Instead, the monitor incorporates a special lens that sends different signals to each eye, as long as you’re sitting in a “sweet spot.” The 3-D effect is similar to that produced by those novelty postcards with a grooved plastic layer on top.

Active glass systems: Samsung and Mitsubishi are offering “3-D Ready” sets that rely on LCD glasses that alternate their polarization between the left and the right eye, in time with the refresh rate on the TV monitor. In effect, you see one frame with the left eye, the next with the right – repeated, say, 60 times a second.

Passive glass systems: Hyundai, JVC and other companies are working on TV sets that can switch between the usual 2-D display and a 3-D display meant to be seen with plain old polarized glasses – the kind of glasses that come by the binful at theme-park 3-D theatres. In 3-D mode, every other line carries a clockwise or a counter clockwise polarization. Thus, each eye gets half of the visual information on the screen, but your brain puts it together to create one picture with the 3-D effect.

Watching 3D TV without 3D TV glasses may mean you will see the “blurry” double image.


How does Sky 3D work?

Your brain creates a sense of depth by combining the slightly different perspectives from the left and right eye of the same object or scene into a ‘merged image’ that includes depth information. Delivering the two different images on a single two dimensional screen to the viewer is a challenge as there is only one view available to both eyes.

Sky 3D projects both a left and right image onto the same screen, and then the glasses that you wear filter out the correct image to each eye, to create the sense of depth of real life.

How are 3D images captured?

3D starts with recording content the way that our eyes see it – from two different perspectives. Two HD cameras are used in a special camera rig to take aligned left and right images of the chosen scene so what you see at home is exactly what the cameraman sees whether he’s on the touchline of a football match or in the heart of a car chase in a movie.

The images then make their way through Sky’s broadcast infrastructure where they are compressed and positioned side by side in a single HD frame.

How are 3D images broadcast?

Sky 3D is broadcast using a normal HD broadcast channel, over existing Sky infrastructure which means you can enjoy Sky 3D using your Sky+HD box, provided you have a 3D ready TV.

How are 3D images viewed?

There are two different 3D TV technologies coming to market now.

The first, polarized screens, project both the left and right images onto the screen at the same time, and then a special filter on the glass polarizes the left and right images differently, such that your 3D glasses then use a different left and right lens to filter the correct image to each eye. Your brain then does the rest.

Active shutter glasses alternately ‘block’ one eye and then the other in sync with the TV, which is alternating left and right images on the screen at a very high rate (usually a minimum of 50 frames per eye per second). this is fast enough that the brain sees no gaps, and again, takes the two different views from left and right eyes to merge them into an image with depth.

The best way to choose the one that suits you is to go to your local retailer and take a look.

Active v Passive 3D explained

Active v Passive 3D refers to the type of glasses you have to wear to watch 3D.

Active glasses contain LCD lenses that alternately ‘black-out’ each eye depending on whether the right or left image is being displayed on the screen. They are referred to as active because they require a battery to operate the LCD lenses. The shuttering occurs so rapidly that you don’t see the shutters just the amazing 3D picture.

Passive glasses use polarisation to separate out the left and right image. They are referred to as passive because the glasses do not require any power to operate them. These work with polarised TVs that use circular polarisation to deliver the two images to the viewer. The TVs have a polarized filter integrated into the screen, and when switched into a 3D mode, the filter orientates the light emitting from screen differently for the left and right image. When you put on the passive polarised glasses the left lens has a filter that blocks out the right image and right lens has a filter that blocks out the left image.