Short of actually jumping into your TV set, there's no better way to get beyond the usual two-dimensional entertainment world we're used to than 3DTV. Starting this year, companies are bringing 3DTV to a living room near you. The stereoscopic 3D-cinematic experience that's now available in movie theaters, will soon be available in your own home. Forget the long popcorn lines and seating availability issues, unless you’re the only one on your block with a 3DTV, in which case, expect the crowds to come to you.
Whether you’re looking for 3D sports, 3D movies, or 3D games, manufacturers are doing their best to bring you a more enjoyable, thrilling, entertainment experience. It’s up to you, the consumer, to decide when the balance of content types is right for you to take the plunge into 3D. What’s going to be the hottest 3D entertainer? It’s a tad hard to predict at this point since we’re at the edge of this new technology, but it is interesting to note that ESPN, Sony, and others are already betting that 3D sports viewing will be a major driver.
Believe it or not, the technology behind 3DTV dates back to the 1950s, when TV first became popular in the US. The first 3D movie ever produced, called Bwana Devil (United Artists), was viewed across the US in 1952. The following year, a second 3D movie, House of Wax, was produced featuring 2D sound.
Nancy Fares, business manager for DLP (digital light processing) Cinema with Texas Instruments, says older 3D technologies used anaglyphic (red and blue lenses) glasses. Fares says, “A Texas Instruments-based DLP 3D HDTV (high definition television) system, with shutter glasses, gives exceptional color fidelity and superior picture depth in comparison to other technologies used in the past.” But shutter glasses aren’t the only 3D glasses around, these days. Polarized 3D glasses, the type you wore when you saw Avatar in the theater, create an illusion of color-rich 3D images by restricting the light that reaches both eyes.
Alfred Poor, a consumer-electronics expert and creator of Alfred Poor's HDTV Resource Center (www.hdtvprofessor.com), says to begin with, the term 3D is actually a misnomer. Poor explains, “Three-dimensional viewing means that you perceive depth, and distance, but the cues are abundant in 2D images, especially the moving ones. People use ‘3D’ as shorthand for ‘stereoscopic’, which means different images delivered to the left and right eyes.”
Poor says people with vision in only one eye cannot perceive stereoscopic imaging by definition, and yet they are quite capable of perceiving depth in what they see. “As a matter of fact,” he continues, “stereoscopic images are identical when viewing objects at a distance; the differences only come into play for objects within 30 feet or so.”
So, when you think about 3DTV technology, Poor says the assumption is that you mean stereoscopic television. He adds, “The fact is, 3DTVs work in many different ways. Fundamentally, however, they are all the same—they deliver different images to the left and right eyes of the viewer. The brain then assembles these two images and infers depth information from the differences.
Want to hear a big secret? 3D television is not what you think it is, or at least what some experts lead you to think it is. There is no magic trickwhen it comes to how 3D technology actually works. 3D’s goal is to trick your binocular-based brain into thinking that the 2D images you are viewing actually contain depth. Today, there are a growing number of techniques to produce and display 3D television. But now that the secret is out, the most common 3D technology used today is stereoscopic.
With that said, here’s a breakdown of the most common technologies for projecting stereoscopic image pairs to your eyes. Anaglyphic 3D uses passive red-cyan glasses. Polarization 3D uses a pair of passive polarized glasses. Alternate-frame sequencing is another type of stereoscopic technology that uses active shutter glasses and headgear to receive the images. And finally, we have autostereoscopic displays, a form of stereoscopic imaging that does not require glasses to experience the illusion of depth.
Some 3D-ready TV sets available today are already being used in conjunction with a pair of LCD shutter glasses. The television is actually running the show in this case, telling the glasses which eye should see the image, which in turn creates the stereoscopic image. These kinds of 3DTVs are typically supporting the latest HDMI (1.4) and a minimum refresh rate of 120Hz.
While there’s still tons of confusion about what exactly 3DTV is, on of the most popular questions people ask is “Can I watch 3DTV without a pair of glasses? The answer to this question is both yes and no. The fact of the matter is we’ll be waiting a while for the no-glasses 3DTVsets, but many manufacturers and industry experts are saying that this is just around the corner.
As of today, some of the bigger players including LG, Samsung, Phillips, and Mitsubishi have already created 3DTVs, but they only work with a pair of 3D glasses. However, another less common 3D technology, which combines holographic and stereoscopic components (essentially light and reflections creating 3-dimentional shapes), is able to create the 3D effect without using 3D glasses.
Some TV manufacturers, however, have already put their stamp on RealD glasses (www.reald.com), which can be used with 3D-ready HDTVs. Sony and JVC, for example, have both approved RealD glasses. This is a good move for both companies, especially considering they are going to be the standard eyewear in the upcoming 3D television boom this year. So if you buy a set of these glasses, you can expect them to be compatible with the majority of 3DTV manufacturers.
The two main consumer 3D technologies today are passive polarized and active shutter. According to Phil Lelyveld, program manager of the Consumer 3D Experience Lab in the
Entertainment Technology Center at the University of Southern California (see our tour of the lab here), passive polarized displays have a thin film on the surface of the screen which causes the light for one eye's image to rotate clockwise and the light for the other eye's image to rotate counterclockwise. He says the glasses have paired circular-polarized lenses in them so that the left eye only gets the image intended for the left eye, and the same for the right eye.
Active shutter displays rapidly flip between the left eye and the right eye image on the screen (120 times per second is currently common). Lelyveld elaborates, “Active shutter glasses have liquid crystal lenses and built-in electronics that synch up with the TV. When the TV is showing the image for the right eye, the electronics in the glasses makes the left eye go black so only the right eye sees the image. When the TV is showing the image for the left eye, the electronics in the glasses makes the right eye go black so only the left eye sees the image.”
Lelyveld says passive polarized displays are currently more expensive to manufacture than active shutter displays, but passive polarized glasses are much cheaper to manufacture than active shutter glasses.
It doesn’t appear that the 3D world will stop at technology and functionality choices anytime soon, and it will only get more complicated as the technology increases in popularity. Take HMDs (head mounted displays) as an example; these 3D glasses look like glasses from the future. According to Lelyveld, they contain one small video screen for each eye and built in ear buds. The glasses start at $100, and the more expensive models have motion sensors for immersive game play. You can often see HMDs advertised in in-flight magazines, because they are great for watching 2D movies on a long trip.
Autostereoscopic displays, Lelyveld notes, produce a 3D image without glasses, but the viewer must be in a “sweet spot” to see the effect. He comments, “Much progress has been made in creating displays with many sweet spots and narrowing the zone between the sweet spot. Many people do not expect autostereo displays to be ready for the consumer market for at least five to ten years. Until then, they work amazingly well for capturing people's attention as marketing displays in public spaces.”
The one exception to this, Lelyveld says, may be cell phones and laptops. “They are normally used by a single person, and people tend to tilt the screen for the best view. So it is a natural first entry point for auto stereoscopic in the consumer market.”
Another 3D technology, called anaglyph, uses the red/green, red/blue, or other two-color combination glasses. Anaglyph takes the two colors in the lens out of the image in order to create the 3D effect. This leaves you with a nearly black-and-white 3D movie. This technology does not produce the color-rich experience of all of the other technologies mentioned. Anaglyph is, in Lelyveld’s opinion, the 3D of the past.
According to Phil Lelyveld, program manager of the Consumer 3D Experience Lab in the
EntertainmentTechnologyCenter at the University of Southern California, the conversion of the entire infrastructure from analog to digital is a major reason why 3DTV is so popular. Lelyveld explains, “Alignment of the left eye and right eye images is the key to the long-term enjoyment of 3D. Misalignment of the two images leads to eye strain and headaches. Unlike 3D film capture, 3D digital cameras that are conjoined never fall out of alignment.”
Lelyveld says when it comes to widely spaced digital cameras, misalignment can be corrected in post production. He says unlike film post production, misalignment, left-eye and right-eye color balance, among other issues, can be easily corrected in the post production digital work flow. “Unlike 3D film projectors,” he notes, “which can vibrate out of alignment, or single-strip 3D films, which can warp as they pass through the projector, digital 3D projects are always in alignment and distortion-free.”