American Cinematographer, September 2002

212-244-8585 www.21stcentury3d.com

Pushing Stereoscopy: A Unique 3-D Video SystemBy Ray Zone

Despite the fact that Canon has discontin-ued production of the 3-D lens for its XL1 camera(see AC Aug. 2001), Jason Goodman of 21stCentury 3D has moved forward with stereoscopicvideo in developing a new system he calls "960p,"based on dual Sony DXC-9000 cameras.

"It's a high definition stereoscopic formatthat takes its name from the HDTV standards it isbased on," says Goodman. "By utilizing two720x480 progressive (480p) video streams, we areable to produce high definition stereoscopicimages with low cost standard definition tools."

Goodman also notes that there are certainadvantages of dual video recording over the alter-nating field process used by the Canon XL1 3-Dlens. "The XL1 3-D camera lens was unsuitablefor blue- or greenscreen composite work,"Goodman says. "The compressed video files, the4:1:1 color space, and sequential recording of theleft and right eye images were all limitations."

By utilizing the built-in "feature" of NTSCvideo, sequential left and right eye images wereneatly stored on odd and even fields. "This is great

for telling the lens when to photograph each image andtelling shutter glasses when to open and shut," saysGoodman. "but it can be bad for stereo photography.Because the images are recorded sequentially, there is a1/60-second time differential between the capture of leftand right eye images. In many cases, this causes stereopairs to be mismatched. Photographing anything with arelatively high degree of motion (the movement of fingerson a hand for example) may exhibit temporal artifacts anda breakdown in stereoscopy. By switching to a two chan-nel system, this problem is eliminated."

The DXC-9000 camera uses three 1/2" CCDs.With progressive scan technology, the camera can cap-ture objects moving at high speeds and produces clearimages with high horizontal (720 TV lines) and vertical(480 TV lines) resolution. A built-in frame memory pro-vides three types of output signals, including a non-inter-laced signal."I got the DXC 9000s because they were the only camerathat fit the qualifications for progressive scan and broad-cast quality," says Goodman. "They also allow us to docomponent video uncompressed with 4:2:2 color spacewith the option for 4:4:4"

While maintaining the benefits of progressivescan acquisition, the output signals provide system com-patibility with existing video equipment. The DXC-9000uses square pixels for minimum distortion of the image

and is ideal for computerizedimage processing applications. Theindividual cameras weigh in at 1.68pounds each, and Goodman hasassembled a system to record toBeta SP.

"The DXC-9000 outputsRGB component video which is notsuitable for recording to Beta SP inthis particular case," saysGoodman. "So we used two SigmaElectronics black boxes to convertthe RBG component video intoYUV component video and thenrecorded to the two separate Betadecks." Using "video out/video in"external sync on the two Betadecks, field accuracy was main-tained.

"We have one of the betadecks sending time code to theother so the in and out points foreach shot match," says Goodman."This makes editing much easier.We log all the footage from the lefteye tape and then just re-save thebatch capture list, changing the filenames to include a right eye suffix." A Horita mini-portable blackburstgenerator is used to provide exter-

American Cinematographer, September 2002

212-244-8585 www.21stcentury3d.com

nal sync to the two cameras toensure simultaneous image cap-ture for left and right eye chan-nels. The camera adapter unit pro-vides AC power as well as a multi-pin cable that allows for externalsync input. A camera remote con-trol unit also provides easy accessto various camera functions.

To preview the 3-D materi-al during production, a fieldsequential 3-D multiplexer is usedto mix composite video outputfrom the two Beta SP decks into asingle 3-D video stream. This isvery useful for comparing outputof the two cameras and ensuringvideo input at the Beta decks. Ahead-mounted display (HMD) orliquid crystal shutter (LCS) glass-es and a variety of other meanscan be used for preview.

"Both cameras ran com-posite video into a 3-D multiplexerprovided by Andrew Woods atCurtin University of Technology inAustralia," says Goodman. "Thisallowed us to preview 3-D in realtime and compare focus, bright-ness and other characteristics on

screen as we shot."The first 960p project that

Goodman has completed with hisnew stereoscopic video system isAvandia 3D, a seven-minutemovie produced for the pharma-ceutical companyGlaxoSmithKline and recentlyshown at the American DiabetesAssociation convention. Avandia3D combines live-action footageof actors shot in front of a green-screen and composited with com-puter generated (CG) imagerydepicting the bloodstream andhypoglycemia at a cellular level.It's a computer-generated fantas-tic voyage in 3-D into the humanheart and bloodstream that's a bitlike a traditional "ride film" usuallyseen in the Imax format.

"The analog componentfootage was captured with theNewTek Video Toaster via analogcomponent, uncompressed andbrought right into Adobe A f t e rEffects," says Goodman. "I want-ed to stay in component colorspace to preserve as much imagequality and color fidelity as possi-ble. While the Sigma transcoderbox is not necessarily an idealsolution, it seems like the bestavailable choice for the presenttime."

Working in the realm ofcomputer imagery provided greatflexibility for manipulation of thestereoscopic image. "We manipu-lated the stereo window with After

American Cinematographer, September 2002

212-244-8585 www.21stcentury3d.com

Effects by moving left and right eyeimages closer together or furtherapart depending on the need," saysGoodman. "We werecompositing the live actors into aCG world, so we set up the CGshots with convergence or cameratoe-in. Once we got the CG worldlooking the way we wanted, weintegrated the actors in a way thatmade them appear to be at theproper depth relative to their sur-roundings."

To project Avandia 3D at theconvention, two independent DVDswere encoded progressive scan.The DVDs played in two off-the-shelf DVD players controlled by aDave Jones-designed sync box.Each DVD player was hooked up toa separate Christie DigitalVistagraphics 5000 projectorthrough a component video con-nection. The Christie DLP projec-tors each have 5,000 lumens oflight and project through properlyoriented linear polarizers onto a10’8” x 6’ silver screen. Projected inthe 16x9 aspect ratio, Avandia 3Dwas watched by the audience usingpaper polarizing glasses.

"The projected 3-D imageswere pretty bright," says Goodman."DVD is important in this system.The disc-based format allows us toeasily synchronize the two 480pstreams and presents a very highquality image. By sidesteppingNTSC interlacing, we are achievinga digital projection format using

inexpensive DLP p r o-jectors that produceSVGA resolution, whichcan represent everypixel in our image with-out scaling. By matingtwo DLPs to two com-puter-controlled gen-locked DVD players,we are able to present480 horizontal lines ofdata to each eye.

"Unlike the XL13-D which takes a720x480 frame and cuts it in halffor each eye," continuesGoodman, "this system gives youfour times the resolution becauseit's a full frame per eye. The braininterpolates the dual 480p signalsinto a 960-line display because allthat data is there, merging the twoindependent channels. That's thekey to the system."

Modification of the DXC-9000 cameras was not without itschallenges. To get the stereo basebetween the two cameras down toa workable 2 3/8 inches apart,Goodman found he had to use theSony VCL-707BXM lensesbecause of its smaller lens barrel."This is actually a macro lens,designed to photograph objectsno more that 17 inches from thecamera," says Goodman. JohnMerritt, chair of the StereoscopicDisplays and Applications confer-ence and senior consultant withThe Merritt Group in Williamsburg,

Massachusetts, consultedwith Goodman to find asolution. Custom optics were creat-

ed for the lenses by SteveManos, formerly of CenturyPrecision Optics."Originally, the lens was a7.5mm to 52.5mm zoom,"says Goodman. "The modi-fications created a need to

lock the focal length and lose thezoom capability. The focal lengthswere matched by our optical engi-neer and locked in place at7.7mm. Currently, aperture andfocus functions are not linked. Forthe first shoot, we were just verycareful to match them as closelyas possible."

Goodman isn't the onlyone assembling a stereoscopicvideo rig. Paradise FX inHollywood has tested two SonyCineAlta 24p HD camcordersmounted at right angles in a hous-ing frame. James Cameron hasbeen using a similar rig for under-water filming of Ghosts of theAbyss, which is destined for thelarge-format Imax screen. Wi t hdigital processing of the HDfootage, extra definition is addedand recorded out to film for pro-jection in the 15/70 format.

"Imax is the obvious kingin this arena," says Goodman,"but without Sony's budget, whocould afford to make a film in thatformat? Eventually, however, oureyes are on HD." For now, 21stCentury Media will service thepharmaceutical and medicalindustries with 960p 3-D moviesto showcase at trade shows andconventions.