'Slasher' film projects state-of-the-art 3-D

http://www.eetimes.com/news/latest/showArticle.jhtml?articleID=212900987
R. Colin Johnson (01/16/2009 12:16 PM EST)
PORTLAND, Ore. — The first horror film to be encoded with advanced 3-D technology opens this weekend. A 3-D remake of the 1981 independent film, "My Bloody Valentine," uses RealD Cinema's stereoscopic encoding process, enabling viewers to experience state-of-the-art 3-D by wearing polarized glasses in a theater. The horror film is the first of 14 stereoscopic 3-D films to be release in 2009 using the RealD encoding process. Its developer claims a large patent portfolio of 3-D video technologies, with some of its over 150 patents dating back to the work of chief technology officer Lenny Lipton, who pioneered 3-D with his company, StereoGraphics, which was acquired by RealD in 2005. "We produce virtually every 3-D system in existence: active LCD shutter, linear polarized, circular polarized and color spectral systems, which are used in different applications areas," claimed Josh Greer, president and CEO of RealD (Beverly Hills, Calif.) Stereographics' main product was CrystalEyes (now marketed by RealD), which allows users to view 3-D stereographic images on their PC using wireless LCD shutter glasses. Stereoscopic images are viewed by supplying different images to the right and left eyes, thereby showing slightly different perspectives--shifted by the distance between the eyes--which the brain interprets as a 3-D visual field. LCD shutter glasses are said to deliver the highest quality 3-D stereoscopic view based on their 10,000:1 contrast ratio between right and left images. The glasses will be used by several vendors of future 3DTV systems. Texas Instruments, for instance, will use LCD shutter systems for 3DTVs based on its digital light projection technology. Still, these systems require active wireless LCD shutter glasses to sense whether the left or right image is displayed. For theater owners, that means expensive LCD glasses have to be distributed to viewers, then collected afterwards for cleaning and recharging before they can be used by the next audience. Some iMAX theaters have installed dishwashers dedicated to cleaning active LCD shutter glasses between shows. Most theaters will use disposable polarized glasses. "For the cinema, we wanted to deliver the best image quality that was possible within the infrastructure and operating responsibilities of a theater," said Greer. "So we chose a passive polarization system where you don't have active glasses that need to be cleaned and recharged between shows." Polarization is the second best option for delivering image quality. It works by moving the active element into the projector, which then polarizes the left and right images before they reach the screen. Linear polarization schemes require two critically-aligned projectors with passive polarization filters in front of each projector. One imparts a 45-degree angle of polarization; the other a minus-45 degree angle of polarization for the right and left images. Linear polarization has been chose by JVC for its forthcoming 3DTV system that uses chips from Sensio Technologies Inc. (Montreal,) to supply the separate right and left images to two JVC projectors. RealD's innovation for the cinema was to eliminate the need to critically align two projectors by installing the polarization mechanism's active electronics into a single digital projector. RealD's patented ZScreen is an active LCD that is placed in front of the single projector to properly polarize the light for sequential display of left and right images. The ZScreen is a custom LCD that adds polarization to the light passing through it. By synchronizing the angle of polarization imparted with the sequential display of right and left images, it eliminates the need for two projectors. Polarization matches up well with current theater infrastructures, since movies can be viewed with disposable passive glasses that don't have be cleaned and recharged between shows. But linear polarization requires that users keep their heads aligned with the screen to within 2 percent to prevent ghosting caused by images leaking from one side to the other. Circularly polarized glasses, on the other hand, allows users to tilt their heads as much as 35 degrees without reducing contrast ratio, thereby eliminating ghosting. ZScreen works by alternatively imparting either clockwise or counterclockwise circular polarization to left and right images, which are sequentially projected. A digital projector equipped with the technology alternatively displays left and right images at six times overspeed, or 144 frames/sec. Because the source video is just 24 frames/sec, each eye receives an image three times per each movie source frame. As a result, the images are perfectly aligned since only a single projector is used. Moreover, each eye perceives a continuous stream of frames since the gap between them is smaller than the gap between frames of a traditional 24-frames/sec movie. For future 3DTV systems, however, RealD said it remains agnostic on the format. The company recently release a system that assists developers struggling to standardize on a 3DTV format. Commissioned by the U.S. Navy, RealD's Pod system is a smart HDMI repeater that works between the an HD source and a 3-D display, automatically converting any input formats into the output format for a particular 3-D television.