sign in sign up
<<
Home , Digital Light Processing, Projector, Stereoscopic motion

TECHNICAL PAPER

The Stereoscopic Cinema: From Film to Digital Projection

By Lenny Lipton Lenny Lipton

A noteworthy improvement in the projection of stereoscopic moving awaited the invention of commercial- images is taking place; the image is clear and easy to view. Moreover, the quality sheet polarizers by Edwin setup of projection is simplified, and requires no tweaking for continued Land, who applied the material to 3 performance at a high-quality level. The new system of projection relies stereoscopic eyewear. on the Texas Instruments Digital Micromirror Device (DMD), and the The Norling approach became the model for the theatrical motion pic- basis for this paper is the Christie Digital Mirage 5000 and ture stereoscopic boom of the early StereoGraphics selection devices, CrystalEyes and the ZScreen. 1950s. In those days theaters had two in the booth for changeover from reel to reel, provid- tereoscopic cinema has not problems of the past to better appreci- ing an opportunity to modify the Sbecome an accepted part of the ate the virtues of the improvement setup to run interlocked left and right neighborhood theatrical experience described. projectors (Fig. 1). because the technology hasn’t been Efforts It may well be that problems in the perfected to the point where it is satis- projection booth bear the major share fying for either the exhibitor or the The first successful (and influential) of responsibility for this short-lived viewer. However, the medium has commercial use of full-color stereo- effort. Polaroid researchers Jones and become widely accepted in theme scopic movie projection in the U.S. Shurcliff4described the artifacts relat- parks and location-based entertain- was in 1940 (a similar film was pro- ed to projector synchronization and ment where some of the problems jected in monochrome in 1939) at the shutter phase. The same kind of dual- have been overcome. For the most World’s Fair in New York. John A. projector scheme is used in today’s part, the projection technology used in Norling produced and photographed a theme parks. The theme park theater theme park theaters is identical to that film showing the assembly of a is more manageable than a neighbor- first employed commercially in 1939: Chrysler automobile. The film was hood theater, since more diligence can two projectors run in interlock with shot with a 35mm rig and pro- be devoted to making a touchy system lenses projecting through sheet polar- jected with a pair of projectors in work. izer filters. Audience members wore interlock. As mentioned, polarization polarizer analyzer eyewear for image was used for image selection.1 Single Projector Methods selection (the means for getting the The film debuted some four The history of the cinema teaches left eye image to be seen only by the decades after the suggestion was first that systems requiring multiple left eye and vice versa). made for using polarization as a machines, for color, sound, or wide- It is expected that digital projec- method of image selection. This delay screen, will be displaced by single tion, which produces a clean ghost- from idea to successful implementa- projector solutions. The same factors free image and requires the use of tion is typical of technology in gener- apply to the stereo-cinema. For exam- only one projector, will undoubtedly al, and the stereoscopic medium in ple, in the early 1980s, attempts were usher in a new and superior version of particular, in which innovation has made to commercialize single projec- the medium. First, let us take a histor- sometimes depended upon the arrival tor methods that placed left and right ical detour in order to understand the of new enabling technologies. In this images above and below each other case John Anderton2first suggested with Techniscope-style (two perf polarization for selection using the high) subframes.5Special dual A contribution received on April 26, 2001. Lenny Lipton is with StereoGraphics Corp., San Rafael, CA cumbersome piles-of-plates tech- that incorporated polarizing filters 94901. Copyright © 2001 by SMPTE. nique, but a viable implementation were required for projection.6

586 SMPTE Journal, September 2001 • www.smpte.org THE STEREOSCOPIC CINEMA: FROM FILM TO DIGITAL PROJECTION

In the early 1980s a few films were shot and released using this approach. Unfortunately, one of difficulties Screen had been replaced with another: this subframe method is considerably less bright than the dual-projector method. Polarizing It was introduced at a time when Filter screen sizes were larger than ever and more brightness was needed. In addi- tion, while synchronization of two projectors was not an issue, it was too Left easy for the projectionist to splice reels together at the subframe line rather than at the frame line. The Right result is the projection of a pseudo- stereoscopic image. The viewing of a left perspective Polarizing view with the right eye and vice versa Glasses does not happen in the visual world; people have a hard time articulating the nature of the problem. The result Figure 1. Polarization image selection. Sheet polarizers are used over the projection lenses of this mistake is the destruction of and as analyzers in eyewear. must conserve polarization. the raison d'être of the medium caus- ing audience discomfort. This sub- frame technique has more or less fall- en by the wayside, not having been able to live up to its promise. Anaglyph and In addition to the polarization method, two other technologies have been considered for theatrical stereo- scopic projection, both of which offer a single projector solution. One, the anaglyph, employing complementary colored images, with selection eye- wear using similar complementary colored filters, has a long history of on-again/off-again use since the early days of the motion picture industry. Although it requires only one projec- tor, a monochrome image and eye have precluded its acceptance. The Vectograph, a trade name of the Polaroid Corp., was another con- tender, and it has interesting similari- ties to the anaglyph, except that it allows for full color (Fig. 2). At a spe- cial session of Siggraph about a decade ago, a test reel produced by Polaroid in conjunction with Technicolor was shown in a Manhattan screening room. The Figure 2. Vectograph projection. A single film contains both left and right images with each image was extremely bright and sharp having the ability to polarize . This drawing is from a 1942 patent by Land. with excellent stereoscopic effects.

SMPTE Journal, September 2001 • www.smpte.org 587 THE STEREOSCOPIC CINEMA: FROM FILM TO DIGITAL PROJECTION

The Vectograph process imbibes open and close in synchrony with the result is a -free stereoscopic polarizing dyes onto two reels of spe- projector shutters. moving image (Fig. 3). cially prepared film that are then Laurens Hammond9invented the It’s not surprising that this method cemented together.7This duplitized first commercial motion picture works, because it is an extension of process was never used commercially eclipse system, Teleview, used in the basic motion picture technology. The for motion picture projection. screening of the movie MARS,at the interrupting projector shutter occludes Selwyn Theater on Broadway in New the film as it is transported, to prevent Eclipse Technique York City in 1923. Mounted on the travel ghost, and also interrupts the Another approach worthy of atten- back of every seat in the theater was projected frame when it is at rest, to tion, because it is the basis for the an adjustable gooseneck, and mounted increase the repetition rate of the pro- improvement in technology described on the gooseneck was a spinning jected fame in order to satisfy the crit- here, is the eclipse or occlusion mechanical shutter in electrical syn- ical flicker frequency condition. The method. It has a great deal in common chronization with the projector’s shut- result is that half the time the viewer with the polarization projection tech- ters. When the pie-shaped shutter’s is observing “nothing” on the screen, nique since both use dual interlocked movement uncovered the right eye, since the image is blocked. The projectors. It was first proposed in the right projector shutter was also stereoscopic occlusion technique fills 1855 for the projection of slides,8 open. At that moment the viewer’s in the periods of nothing with image. requiring the images for the left and left eye was blocked, so was the left Until IMAX’s revival of the right eyes to be alternately blocked projector lens. As the viewer shutters process for dome projection, Teleview and passed. The projector shutters are continued to rotate, the left view was was the only commercial use of this out of phase with each other, and the unblocked and so on and so forth. If motion picture process for over 60 shutters used in the selection devices the repetition rate is high enough the years. IMAX’s addition was the use

Figure 3. Teleview theater setup. Spinning shutters cover projector lenses and the viewers’ eyes. The drawing is from the 1924 patent by Hammond.

588 SMPTE Journal, September 2001 • www.smpte.org THE STEREOSCOPIC CINEMA: FROM FILM TO DIGITAL PROJECTION of liquid crystal shutters for the selec- Binocular Symmetries Accommodation and tion eyewear, an approach that had In addition to the ghosting issue, Convergence (A/C) been used for some years for stereo- there are other factors that determine There is another phenomenon pecu- scopic graphics. the visual experience one will have at liar to the display of plano-stereoscop- Ghosting a stereoscopic movie. These factors ic images (a stereo image made up of need to be understood to grasp the planar left and right perspective The cross-talk artifact of polariza- extent of the improvement resulting views) that may detract from the tion image selection is one of the art’s from the digital projection technique enjoyment of the image. It is the most serious technical problems. The described here. One set of concerns breakdown of accommodation (the term ghosting is sometimes used in has to do with the correlation of the muscle controlled change of shape of place of cross-talk to describe the left and right images, or what has the eyes’ lenses to accomplish focus- visual result, an effect that is similar been termed binocular symmetries.11 ing) and convergence (the muscle- in appearance to a double exposed The left and right images must be sub- controlled movement of the eyes that image. Despite the fact that good lin- stantially identical in all ways except allows them to rotate as a coordinated ear polarizer sheet filters are avail- for the entity of parallax. That means, pair to accomplish fusion). able, they are imperfect devices and within specifiable tolerances, the left The A/C breakdown occurs when will pass a small amount of unwanted and right images must have identical viewing a stereoscopic image, and light in their crossed or occluded magnification, color balance, and illu- does not take place in the visual state. The problem is exacerbated mination, and they must be aligned in world. We are accustomed from birth because of the Law of Malus,10which, the vertical so that a horizontal line to having our eyes focus and con- applied to the case at hand, teaches can pass through corresponding verge on the object we are looking at. that even a few degrees of head tip- points. For a projected stereoscopic display ping will produce a substantial In this regard the Vectograph and the habituated A/C response breaks increase in cross-talk. field-sequential electro-stereoscopi- down, since the eyes are focused on The dynamic range of the projec- cally projected images are beneficial the plane of the screen but conver- tion filters’ polarized light in combi- in that both use the same optical sys- gence is determined by parallax. nation with the eyewear analyzers is a tem for both perspective views. Since The muscles and neurological measure of the ratio of light transmit- they are treated identically, the condi- pathways that control A/C are sepa- ted with the filters’ axes parallel to tion of binocular symmetries will be rate, but we become habituated to that measured with the filters’ axes fulfilled. As described by their working together. Viewing a crossed. Measured on an optical Spottiswoode et al.,12 when such a projected stereoscopic image derails bench, sheet polarizers can have a condition is fulfilled we have a neu- this learned response, and for some dynamic range of several thousand to tral stereoscopic transmission system. people makes it difficult to enjoy a one. After reflection from a metallic In addition, there are temporal con- stereoscopic image. Interestingly, coated screen, the dynamic range can siderations. Although moving stereo- when looking at images from some be reduced, especially for corner seat- scopic images must be captured considerable distance, in a theater ing. simultaneously, they can be success- setting for example, the breakdown is Cross-talk is dependent on the fil- fully projected out of phase to within less troublesome, because the eyes ters’ characteristics and the properties a specifiable tolerance.4 If dual are focused at (or nearly at) infinity. of the screen. The screen is an imper- motion picture are used, their Most of the author’s work has fect device with respect to its conser- shutters must be adjusted to run in been in designing systems for view- vation of polarization characteristics. phase and video cameras must be gen- ing images on workstation monitors, Having said this it should be noted locked. For computer generated which are typically 20 in. or so diag- that there are some stereoscopic pro- imaging, it should be a given that onal and viewed from only a few jection screens that do a reasonably action in left and right image views feet. This is the most demanding sit- good job of conserving polarization. will be “captured” at the same uation for viewing a (rear) projected Linear polarization selection is the moment. stereo image, since the eyes must accepted standard for stereoscopic Field or frame-sequential electro- accommodate for the close distance. projection, but if care isn’t taken, stereoscopic displays cannot project These displays, based on CRT moni- ghost images can result that are left and right images simultaneously; tors, have afterglow characteristics noticeable for high-parallax (object rather, they present left and right that contribute to cross-talk or ghost coming off the screen) and high-con- images in sequence. However, images. Working with a digital pro- trast images. As mentioned, even a because the field rate is high enough, jector, which contributes no ghosting slightly tipped head can produce a usually 100 per sec or higher, a tem- artifact, proves that the presence of ghost image. poral artifact is never seen. even a faint ghost image may be as

SMPTE Journal, September 2001 • www.smpte.org 589 THE STEREOSCOPIC CINEMA: FROM FILM TO DIGITAL PROJECTION important as the A/C breakdown. When viewing images in a A single motion picture projector cannot be Brewster lenticular ,13 like the familiar ViewMaster, there is used for the field-sequential or occlusion no cross-talk, because there are two approach, but it comes naturally to electronic separate viewing channels. In addi- projection because there is no mechanical limi- tion, the stereoscope uses accommo- dating lenses that help the eyes tation to image transport. In a motion picture focus. Both of these factors make system two projectors are required, as is the looking through a stereoscope the case for Teleview or the IMAX system. most pleasant stereoscopic viewing experience. The Brewster stereoscope is an excellent neutral transmission component and remains the gold stan- duration, and for digital projection the the screen). It uses a type of super- dard for viewing stereo images. vertical blanking is even less. twisted nematic liquid crystal (LC) Electronic vs. Film Projection A major attraction of the single pro- shutters to produce both fast switch- jector approach is that two projectors ing speed and high dynamic range, as A review of the prior art continues do not have to be calibrated to work described by Tilton et al.15 with a brief discussion of cathode ray in concert. In addition, since a single The shutter is a sandwich made of tube (CRT)-based projection. For the optical path is used for both left and two linear sheet polarizers (whose past decade or so electro-stereoscopic right images binocular asymmetrical axes are orthogonal) on either side of images have been projected by CRT artifacts are eliminated. the liquid crystal cell. The cell itself is devices, usually using three tubes and In electronic projection two selec- made up of a thin film of LC material associated lenses. Today they are tion methods are used, one employing contained between two parallel sheets most frequently used for industrial shuttering (active) eyewear, and the of glass. The inside of each glass (VR) or simulation other using a polarization modulator sheet is coated with a transparent con- applications. The technique is related and polarizing (passive) eyewear. As ductor, indium tin oxide. The conduc- to that used for viewing stereo images will be described, these techniques tors have a voltage applied to them on desktop workstations (often for can be applied to digital projection and in this way an electric field can be applications like molecular modeling with great success. set up within the gap of LC material. and aerial mapping). This is a variant When a field is induced, the LC Active Eyewear of the eclipse or occlusion system material becomes isotropic and the described above in which significant The active eyewear approach uses crossed polarizers block light. improvements have been made: elec- wireless battery-powered eyewear Without a field having been applied tro-optical shutters have replaced with liquid crystal shutters that are run the axis of incoming polarized light is mechanical shutters and one projector in synchrony with the video field rate. toggled through 90o, by means of the replaces two. Synchronization information is com- phenomenon of optical activity; in A single motion picture projector municated to the eyewear by means of this mode the shutter transmits light. cannot be used for the field-sequential an infrared (IR) emitter. The emitter CrystalEyes, in conjunction with or occlusion approach, but it comes looks at the computer’s video signal CRT projectors, is commonly used in naturally to electronic projection and seeing the vertical blanking syn- industrial VR applications such as the because there is no mechanical limita- chronization pulse broadcasts coded CAVE.16 Also, simulators with tion to image transport. In a motion IR pulses to signify when the left eye screens from 10 to 30 ft across (often picture system two projectors are and the right eye images are being dis- with projectors set up in a triptych required, as is the case for Teleview played.14The eyewear incorporates an arrangement like that employed by or the IMAX system. IR detection diode that sees the emit- Cinerama) are used. The principal Electronic projection does not have ter’s signal and tells the eyewear shut- contribution of cross-talk comes from to deal with the limitations of film ters when to occlude and transmit. the CRT display’s phosphor afterglow transport and the mechanical pull- An active eyewear product, like and not from the eyewear shutters. down of a frame of film. A quarter of CrystalEyes by StereoGraphics, has The stereoscopic effect is achieved by the motion picture projection cycle, or shutters with a dynamic range better projection of a succession of left and about 0.01 sec, is required for the than 1500:1, which is about an order right images, but CRT projector tubes, pull-down of a frame of film. For of magnitude better than the polarized even when optimized for the stereo- CRT projection the analogous entity, light method of selection (considering scopic task, have phosphors that con- vertical blanking, is a tenth of that in the total optical system inclusive of tinue to glow into the adjacent field.

590 SMPTE Journal, September 2001 • www.smpte.org THE STEREOSCOPIC CINEMA: FROM FILM TO DIGITAL PROJECTION

My team and I became interested in the problem many years ago, and did an experiment to understand the nature of ghosting. Placing spinning mechanical shutters in front of the twin lenses of a stereoscopic , we then coupled a CrystalEyes emitter to the action of the shutters and studied a series of projected images. When viewing the images through active eyewear with high dynamic range shutters, we could see virtually no cross-talk, no matter how high the parallax values. Since the mechanical shutter had no phos- phor afterglow this experiment estab- lished that the CRT-based display devices, and not the selection device, contributed to ghosting. Passive Eyewear An alternative to active eyewear is the ZScreen, which is a special kind Figure 4. ZScreen mounted on a Mirage projector. of LC polarization modulator. It is placed in front of the projection be applied to the cells in order to tune The combination of ZScreen and lens(es) like a sheet-polarizing filter. their birefringence so that the vector polarizing eyewear forms a shutter, The device changes the characteristic sum of the cells’ phase shift achieves although one could make a case for of polarized light and switches a quarter-wave retardation.18 classifying it as a polarization selec- between left and right-handed circu- The projector’s light is first linearly tion method. larly polarized light at field rate. polarized which is next subjected to Audience members wear circular phase shifts based on the voltages Digital Projection polarizing analyzing eyewear. applied to the cells. In combination This paper presents a brief history Although the great majority of the- the cells function as a variable of the technology of motion picture aters showing stereo movies use lin- retarder so that left and right-handed and electronic stereoscopic projection, early polarized light for image selec- circularly polarized light is output in with an emphasis on tion, circular polarized light has the synchrony with the video field rate. the artifacts that can detract from the advantage of allowing a great deal of The dynamic range of the ZScreen enjoyment of the medium. In this way head tipping before the stereoscopic is on the order of 150:1 (when mea- the stage has been set for the reader to effect is lost.17 sured in combination with typical ana- understand the improvements that are The ZScreen uses two liquid crystal lyzers found in off-the-shelf-eye- made possible with digital projection. cells (called pi-cells or surface mode wear). The transition between left and The paper is the result of a working devices) in optical series with their right circularly polarized states is fast, relationship between Christie Digital optical axes orthogonal. Unlike the 0.5 ms, or about half the usual CRT and StereoGraphics Corp. in an twisted nematic cells used in display vertical-blanking interval. attempt to create a stereoscopic digital CrystalEyes, which depend upon opti- Compared with CrystalEyes shutters projector solution. The author and a cal activity, the ZScreen uses phase the dynamic range is lower, but the team of engineers at StereoGraphics shifting of linearly polarized light to ZScreen has its virtues. Its image have been working with the Mirage achieve its electro-optical effect. A quality is on a par with what people 5000 (5000 L) to gain an understand- linear polarizer, at the surface of one have come to expect from stereoscop- ing of its characteristics to create a of the cells (closest to the projection ic movies but with the virtue that head fully integrated stereoscopic solution. lens), has its axis oriented to bisect tipping is possible. In addition, there We have been adapting our the pi-cells’ orthogonal axes. The pi- are venues in which it is more appro- CrystalEyes and ZScreen devices to cells are driven to quarter-wave retar- priate to use cardboard or plastic- digital projection (Fig. 4). In addition, dation but with their electric potential framed eyewear than more costly we have been working to interface the out of phase. A low-voltage bias must active eyewear. projectors with Windows operating

SMPTE Journal, September 2001 • www.smpte.org 591 THE STEREOSCOPIC CINEMA: FROM FILM TO DIGITAL PROJECTION system video accelerator boards. The improvement over a comparable LC problem since the digital projectors projector can run as high as 108 device. can be so much brighter. In the stereo fields/sec at a resolution of 1280 by Since the DMD is intrinsically a mode the digital projector is running 1024 per field. monochromatic device, the three at about twice the usual field or pic- There are two contributions to DMDs must be used to produce a ture rate. Half the light is now used that DMD projectors color image that is made up of color- for each perspective view so com- make: they greatly increase image filtered gray scales contributed by pared to the planar mode the light is brightness and substantially reduce each device. The speed with which cut in half. In addition, both the cross-talk. DMD projectors are able to the mirror can be tilted has lead to a ZScreen with passive eyewear or do this because the DMD device is a pulse-width modulation scheme CrystalEyes (both depend upon light light modulator, or reflector, rather wherein the mirrors are turned on and absorbing sheet polarizers for their than a generator of light itself, as is off so that, integrated over time, a sin- electro-optical effect) transmit about CRT projector. The DMD device has gle will have the desired density. 30% of the light. Combined with the no image afterglow to create a resid- It is the speed of the mirrors that duty cycle loss this diminishes the ual left image which will leak into a makes them so interesting for stereo- projector’s light output to 15% of right field (and vice versa), as do the scopic displays. Unlike LC devices, what it would have been. In effect phosphors used in CRT devices; which are slow to switch, the DMD is this reduces the output of the Mirage hence, they do not contribute to cross- fast enough to be used for field- 5000 from 5000 to 750 lumens. Front talk. In addition, like current CRT- sequential stereoscopic application. projection high gain screens, which based stereo projectors, they use the Unlike CRT-based imaging, the DMD also conserve polarization (required field-sequential approach treating does not leak unwanted image into for the ZScreen), can boost the light both left and right images by means of adjacent fields. The titling mirrors are, output by a factor of four (more or a single optical path. The digital pro- essentially, either on or off with an less depending upon the screen), jector is a neutral stereoscopic trans- extremely short duration devoted to restoring the Mirage to an effective mitter, doing no harm to the image. the intermediate position. 3000 lumens. Other configurations of the DMD DMD Projection chip exist, especially for the Road Theatrical Applications The basis for the Mirage projector’s Warrior class of projectors. In this Stereo digital projection will be a imaging is the Texas Instruments case, the speed of the DMD is taken boon for industrial VR users, but there DMD chip. This is a micro-electro- advantage of to produce field-sequen- is a future use of immense impor- mechanical (MEMS) microchip made tial color using the light reflected by a tance. I began this article by stating up of minute tiled mirrors. TI uses the single chip through a rotating color that the stereoscopic medium has not term DMD to refer to the MEMS wheel. Combining colorplexing and become accepted as part of the the- microchip itself, and another term, stereoplexing would be demanding of atrical cinema. Other technologies (DLP) to a single chip, so the three-chip design like sound, color, and wide screen, refer to the image forming engine is used for our application. have become products in daily use in including optics. Until the Mirage series of projec- theaters around the world, but the pro- DMD devices form a Cartesian tors three-chip DMD projectors could jection of stereoscopic movies is an array of (mirrors)19. The mir- not be driven at a high enough field event restricted almost entirely to rors can be tilted on hinged structures rate for stereo applications. One prob- theme park venues. and move through a rotation of +/-10o. lem was the scaling chip employed to Most of the public is now aware The mirrors can be actuated 1000 homogenize video signals of different that a purely electronic or digital cine- times/sec and can be addressed indi- resolutions. The scaling chip would ma is being contemplated as a vidually. take video of whatever field rate and replacement for the present film-based In the case of the Mirage projec- turn it into a 60-Hz signal to be dis- technology. It may well take years for tors, three DMD devices are illumi- played by the DMD. This approach is the transition to take place. In this nated by a single light source through incompatible with the needs of field- context there are a number of techni- an optical path that is divided into sequential stereo, which requires a cal issues to address, such as the three components and high field rate. nature of the format to be used for then reflected off of the surface of the distribution. This is a good time for Light Loss DMDs. The light reflected by the projector manufacturers and others in three DMDs is recombined and The amount of light loss associated the industry to plan for adding stereo- imaged through a single projection with stereo digital projection is the scopic capability. lens. The DMD device has an active same as that associated with CRT pro- The deterrents to the widespread area or fill factor of about 90%, an jection, but ultimately it’s less of a acceptance of the stereoscopic theatri-

592 SMPTE Journal, September 2001 • www.smpte.org THE STEREOSCOPIC CINEMA: FROM FILM TO DIGITAL PROJECTION cal medium have, in principle, been the project might never have taken “Liquid crystal shutter system for stereo- solved by digital projection. The same root. I would also like to thank our scopic and other applications.” Pat. no. 4,967,268, Oct. 30, 1990. projector can be used for showing pla- colleagues Bill Speer and Wayne 15. Mary Tilton and Lenny Lipton, “Fast nar content as well as stereo content Bickley at Christie Digital for their switching 270 degree twisted nematic liq- with the flip of a switch. Digital pro- cooperation. uid crystal device and eyewear incorporat- ing the device,” Pat. no. 5,327,269, July 5, jectors can project images that are References 1994. free of eyestrain or discomfort pro- 16. www.aec.at/center/proj/cavee. ducing components, assuring the 1. John A, Norling, “Three-Dimensional 17. Vivian Walworth, “Three-Dimensional Motion Pictures,” J. SMPTE, 33:612-634, Projection with Circular Polarizers.” SPIE enjoyment of stereoscopic films. The Dec. 1939. Vol. 462, Optics in Entertainment II,1984. future of the stereoscopic digital cine- 2. John Anderton, “Method by which pictures 18. Lenny Lipton, Arthur Berman, Lawrence D. ma is up to us and will depend on the projected upon screens by magic lanterns Meyer, and James L. Fergasen, “Method are seen in relief,” Pat. no. 542,321, July 9, and system employing a push-pull liquid strength of our determination. 1895, (July 7, 1891 in England). crystal modulator,” Pat. no. 4,792,850; 3. Edwin H. Land, Stereoscopic Motion Dec. 20, 1988. Conclusion Pictures: A Special Report to the Directors 19. www.dlp.com/dlp/resources/white papers/ of the Polaroid Corp.,Polaroid Corp., overview. There have been many solutions Cambridge, MA, 1935. offered for solving the riddle of 4. R. Clark Jones and William A. Shurcliff, “Equipment to Measure and Control stereoscopic projection. Some of them Synchronization Errors in 3-D Projection,” THE AUTHOR have fallen by the wayside and some J. SMPTE, 62:134-41, Feb. 1954. are with us to this day. The field- 5. Lenny Lipton, “A Plea for Technical Standards in 3-D,” Amer. Cinemat.,July Lenny Liptonfounded Stereo- sequential system, using occlusion for 1983. image selection, combined with digi- 6. Chris J. Condon, “Film projection lens sys- Graphics Corp. in 1980 and with tal projection, has produced, in the tem for 3-D movies,” Pat. no. 4,235,503, it the electro-stereoscopic indus- Nov. 25, 1980. try. He is actively engaged as the author’s view, the most promising 7. Land, E. H., “Light-polarizing image full solution. The image is free from color,” Pat. no. 2,289,714, July 14, 1942. vice-president of R&D there. binocular asymmetries and cross-talk. 8. Arthur J. Judge, Stereoscopic Photography: Lipton was the first person to Its Application to Science, Industry and produce a flicker-free field- The result is a perfectly beautiful Education,Chapman and Hall: London, stereoscopic moving image. Equally 1950. sequential stereoscopic display important, the result has been 9. Lauraens Hammond, “Stereo-scopic motion and holds 20 patents in the field. picture device.” Pat. no. 1,506,524, Aug. He received an award from the achieved not only in laboratory exper- 26, 1924. iments but also in a real-world prod- 10. Francis A. Jenkins and Harvey E. White, Smithsonian for his invention of uct. Fundamentals of Optics (Fourth Ed.), CrystalEyes. His films are col- McGraw-Hill: New York, 1976. lected in the Pacific Film 11. Lenny Lipton, Foundations of the Acknowledgements Stereoscopic Cinema,Van Nostrand- Archive, and as a filmmaker he I would like to thank my colleagues Reinhold: New York, 1982. has traveled to South America as 12. Raymond Spottiswoode and Nigel L. a cultural liaison for the at StereoGraphics R&D for their con- Spottiswoode, The Theory of Stereoscopic tributions in engineering an integrated Transmission and its Application to the Department of State. Motion Picture, digital projection solution. They Univ. of California Press: A SMPTE member since 1964, Berkeley, 1953. he is the author of Independent include Jeff Halnon, Bill McKee, 13. David Brewster, The Stereoscope: Its Bruce Dorworth, and Jeff Wuopio. History, Theory and Construction, 1856, Filmmaking, which was in print Reprinted 1971.New York: Morgan and for twenty years. Without the persistence of our Morgan. Director of Marketing Ian Matthews, 14. Lenny Lipton and Marvin Ackerman,

SMPTE Journal, September 2001 • www.smpte.org 593