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You can have 3D TV in your own home by Barrie Smith 4  Silicon Chip www.siliconchip.com.au T he third dimension. Has a certain ring to it, doesn’t it? Creating images and viewing them in 3D is still a challenge, but this hasn’t stopped video enthusiasts from punching out some corners of the envelope. Most of us who can hear and see well, take binaural (stereo) sound and binocular vision for granted. Sophisticated devices to replicate the former experience have been around for 40 years or more and today we can enjoy the delights of Compact Discs in the home at little cost and even less fuss. Just sit back, fire up the hifi and listen; no need to sit in the ‘sweet spot’ of the room (unless you’re a fanatic) and no pressing need for headphones. But binocular vision, viewing images in stereo, enjoying the third dimension – that’s a tougher call. And this is the odd thing: image capture by means of the photographic process has been around for 176 years now, while sound recording has been with us only 125 years since Edison began to market his phonograph. Furthermore, it was only about 25 years after Niepce took the world’s first photographic image that stereo cameras became practical devices and people of the Victorian era could sit back and enjoy images of their world in simulated depth, thanks to the Wheatstone hand-held viewer. 19th Century Apparatus And there lies the rub: successful and satisfactory view- ing of the 3D image always has, and still is, accomplished by use of a viewing aid to feed the eyes and brain discrete images, for the left and right eyes. In the 19th century it was the Holmes-style viewer or similar hand-held apparatus. In the mid-20th century 3D viewing could be achieved with spectacles fitted with red and blue/green filters then, thanks to Dr Edwin Land’s invention, cross oriented polarising filters. Over time there have been no-specs, lenticular systems, as evident in commonly available 3D postcards and in a little known Russian projection system. Lenticular 3D has never really taken hold but may see some daylight in new LCD technology developments. Stereo imaging, since its inception, has surged in popularity in fifty-year cycles. The last bump on the 3D radar screen was in 1952, when the pioneering movie Bwana Devil premiered in Los Angeles on the Thanksgiving evening of 1952, bringing “screams from the audience” as a lion “leaped from a screen”. 3D movies carried the burden of recapturing lost audiences infatu- You can watch 3D pictures via your computer or TV set – but you’re still going to need the glasses! Inset is the H3D spectacles and IR emitter. www.siliconchip.com.au October 2002  5 dating back to the 1950s, the third dimension on TV is a comparative rarity. I can well remember the excitement of one Friday night in October, 1983 when the Channel Seven network broadcast nearly two hours of 3D television. 3D on TV – at last. The only downside was that you needed to wear a pair of anaglyph spectacles (left eye looks through a red filter, right eye uses blue/green) to enjoy the offering. You could say the audience response was ‘underwhelming’ – and stereoscopic movies on TV never reappeared on Aussie screens. Perhaps the menu of a Three Stooges short and a low budget Western called Fort Ti was the reason. Viewing Session We can’t hope to do it justice in a printed magazine page but here’s a frame from Ultimate G’s 3D title. This is a single (left eye or right eye) image. ated by commercial TV when it appeared in 1948. Massive 3D Today, you can visit your local IMAX theatre and enjoy a similar but far more vivid experience as the expansive film process runs a catalog of documentaries shot with a pair of massive 70mm motion picture cameras and shown with an even more massive pair of projectors. The audience views the huge image with somewhat bulky and clumsy LCS (Liquid Crystal Shutter) spectacles, delivering a rapid sequence of right/left eye images, triggered by an infrared beam within the cinema. Yes, we have come a long way! 3D movies – but we’re still wearing glasses! To get a hands-on experience of 21st century 3D TV I spent the morning with Mark Giles of Mindflux, a Sydney company importing and distributing 3D gear. To get a ‘second opinion’ I took along this magazine’s editor and publisher, Leo Simpson. Mark very kindly took us through the ropes by first setting up a TV set and DVD player and handing each of us a pair of black specs with grey LCS lenses. The DVDs viewed (and generally available) are all NTSC productions, so you need a compatible player and TV set. Mark then slipped a disc onto the player, Haunted Castle, a title which I had previously seen and been impressed by, in the Sydney IMAX theatre as a 3D presentation. The show is a feast of impressive computer imagery that 3D on DVD Now, thanks to the popularity of DVD as a delivery medium, you can enjoy 3D viewing via your home TV set. And, if our pockets and energies can take us there, we can even craft our own 3D productions. But we’ll still need to wear glasses to enjoy stereoscopic video! However you have to remember there’s 3D . . . and there’s 3D! For a few years now the computer gaming fraternity have been playing with highly enhanced 3D graphics on their PC screens, PlayStation consoles and the like. But this is a graphic display that shows the three dimensions – width, height and depth – rendered as a flat image, in other words as a perspective illustration. Then there’s the 3D process, the topic of this story, which displays graphics as a binocular image, with each eye receiving a discrete image. Without a viewing aid, such as dedicated spectacles, the image is a confusion of two slightly displaced images. However, when the viewer dons the specs, all is revealed and the illusion of the image having true width, height and depth is achieved. You feel you can reach out and touch the subjects on screen. Anaglyph Stereo Despite the existence of a fat backlist of 3D movies 6  Silicon Chip The Ultimate 3D Collection contains a decoder, 3D specs and DVDs. www.siliconchip.com.au takes you through haunted castles and the like - and ends with the obligatory and fairly scary roller-coaster ride. The stereoscopic effect in this presentation is excellent with the 3D effect convincing and not at all an eye strain. I said the roller coaster ride was ‘fairly scary’. Well, to be honest, the scare factor (SF) is directly proportional to the screen size. In the IMAX theatre it was a blast! However, our preview session was run with a 50cm television set so the SF was many notches down from the 30 x 38 metre IMAX mega screen. But it was not hard to imagine the effect from a largish (say a metre or more diagonal) rear projection or front projection television set up. Next up was Ultimate G’s, a more ‘down home’ sort of production about two kids’ dream of becoming pilots, mixed in with some stunt flying. This gained much because it was nearly all shot in ‘true’ (not CGI simulated) live action, with real people in real environments. The production had been carefully photographed and the 3D effect was again convincing and enjoyable but a little more exaggerated than the first film, although not enough to cause eyestrain. It should be noted that both these productions (and possibly most other 3D titles) are packaged on the same DVD as 2D and 3D versions. The 3D video signal consists of alternating left and right images – alternating at the field rate of the video signal (50Hz for PAL and 60Hz for NTSC). The LCS 3D glasses contain shutters that alternately block each eye so that the left eye only sees left images and the right eye only sees right images. When the glasses are taken off, you can see both images overlaid. Depending on the offset between the two images, it can range from blurred to utterly unwatchable. In both cases, any scene with bright areas – such as sky – revealed quite noticeable flicker; it is possible to alleviate the flicker by careful adjustment of contrast. With specs off you see a double image. It was interesting to hold a freeze frame on the DVD and see a clear, non-stereo image, intended for a single eye. ‘Freeze frame’ should really be called ‘freeze field’ as Pricey but effective, the Cy-visor delivers 3D TV direct to the spectacles’ LCD screens. some devices (from TVs, to VCRs, camcorders and DVDs) offer a ‘Pause’ function which holds only a single interlaced field. This factor is, of course, the heart of the whole system. 25 of the fields (in PAL) in any one second carry the left eye image; the other 25 carry the right eye image. So the video Looking for some 3D DVD Titles? Here’s just a few, originally shot for the huge IMAX format and now reduced somewhat! www.siliconchip.com.au October 2002  7 The Standard NTSC and PAL can both be used for the recording and playback of stereoscopic 3D video by storing the left and right views in the even and odd fields of the video signal. This is commonly known as “field-sequential 3D video” or occasionally “alternate-field 3D video”. However, the choice of which image (left or right) to store in which field (even or odd) is arbitrary. A proposed standard is in development that seeks to formalise the image/field polarity for the recording of field-sequential 3D video in the NTSC and PAL standards. picture of 25 complete frames in each second is comprised of two sets of 25 interlaced ‘lefts’ and ‘rights’. The 3D programming on the DVD is accomplished by coding the left and right images onto the even and odd fields respectively (or vice versa). A standard sync extractor chip (eg, LM1881 or EL4581) can be used to identify odd and even fields and hence identify left and right images. The LCS glasses are then driven by this signal. On replay, an IR emitter transmits to the infrared viewing spectacles in the room (a maximum ‘live’ viewing screen-to-specs distance of six metres is quoted by Mindflux). A tiny IR receptor is built into the front of each spectacle frame; at this point the infrared signal fires the opacity/ transparency cycle of the specs’ LCS lenses; the left eye sees only the left image, the right eye sees only the right. Mindflux markets a variety of 3D TV packs. One is the Ultimate 3D collection ($229), containing three DVDs, the H3D signal box (connected to the DVD’s output and mountable on the top of the TV set) and two pairs of wired LCS spectacles. If you hanker for total viewing freedom you can purchase two pairs of wireless specs (H3D Video Eyewear) and enjoy a far more comfortable viewing option, for an additional $235. There is also a computer pack (Eyeforce), suitable for Another 3D viewing option: i-glasses! installation on your Windows PC. Similar setup: a different IR emitter (which sits on top of your monitor) and two pairs of specs. Cost: $249. There are other spectacle options, including headmounted displays (HMD) – Cy-visor is one at $3699 -– which plug directly into the DVD’s video output or the computer’s VGA signal. These are equipped with a pair of LCD screens and of course need no TV set to create the stereoscopic image. And this is where the story gets interesting: Mark ran a DVD computer game, authored in stereo, on a Windows PC, with the monitor set at a refresh rate of 100Hz. Voila! No flicker. My guess is that you could probably run the 3D programming on most screens, even with refresh rates down to as low as 70Hz and enjoy the 3D effect with zero flicker. The point is, you don’t need more than 25 fields to create the stereo image, but you do need more than 25 ‘bursts’ of an on screen image to avoid flicker. That is, each of the 25 fields shown each second can be displayed on screen for a frequency of more than 1:1. 100Hz scan rate So why not run the show on a 100Hz television set to overcome flicker? (Or 120Hz on an NTSC model?) Good idea. But it doesn’t work! For a 100Hz set to work with 3D, the left-image, right- image, Footnote Eyeforce 3D pack, with wireless spectacles. 8  Silicon Chip Andrew Woods suggests that readers can view his conference paper from 1991 “which discusses the principles I used to modify the components of a Grundig 100Hz TV set to achieve 100Hz 3D.” Go to: “The use of flicker free television products for stereoscopic display applications” at http://info.curtin.edu. au/~iwoodsa www.siliconchip.com.au left-image, rightimage field sequence (ie, L1 , R1, L2, R2 etc) needs to be maintained. Mindflux: www.mindflux.com.au Unfortunately most 100Hz Digital Playtime: www.digital-playsets don’t do this; time.com.au/3D/index.asp most implement a modified field EzyDVD: www.ezydvd.com.au/ sequence that regrettably upsets Direct 2U: 07 5455 3554 the 3D content. Some TVs interpolate new fields to improve depiction of 2D motion at 100Hz. Other sets merge the odd and even fields into a single progressively displayed frame, then use a rapid cycle frame store to deliver a double quantity of the complete frames. So there is a range of methods used. For a 100Hz set to work with 3D it needs to convert the 50Hz PAL signal field sequence from the normal sequence of L1, R1, L2, R2, L3, R3, to a “doubled up” sequence of L1, R1, L1, R1, L2, R2, L2, R2, L3, R3, L3, R3 at 100Hz. This is a relatively simple scheme to implement (simpler than some of the 2D schemes) but most 100Hz TV It’s not that scary . . . honest! sets don’t offer it – although some can be modified to achieve it. A secondary issue would be how to sync the LCS glasses with the 100Hz signal. There is considerable debate in 3D TV circles as to methods of tapping into 100Hz display systems to deliver high quality, flickerless stereo images. Dedicated TVs and converters are available in the US and Europe; the URLs are www.3dmagic.com/catalog/price_list/price_list.html#TV and www.micronas.com/press/pressrel-eases/pressrelease. php?s=1&ID=171 Next issue: we take a look at some of the DVD titles and apparatus available in Australia – plus a hands-on trial of a 3D camera adaptor that lets you shoot 3D video with a SC consumer camcorder. Contacts for Hardware and Software Supplies Acknowledgement: Barrie Smith would like to thank Jason Pang and Mark Giles at Mindflux for their help as well as to express his gratitude to Andrew Woods at the Centre for Marine Science and Technology, Curtin University of Technology, Perth WA for additional technical advice and checking. www.siliconchip.com.au October 2002  9