3-D Revolution: The History of Modern Stereoscopic Cinema

Chapter 25: Rebuilding the Z-axis

Rebuilding the Z-axis 25 Stereo Conversion of Motion Pictures Stereographic conversion of flat two-dimensional images is the holy grail of stereoscopy. Though the fundamental principles of such a procedure have been long established, the method and means of repurposing 2-D images to 3-D are still in the process of becoming a mature technology. It is an artistic and perceptual strategy that continues to elude automation. So sensitive is the human sensorium to retinal disparity and spatial perception of the visual world that an automatic means of stereo conversion has yet to be successfully implemented. In addition, with moving images, the amount of visual information that must be manipulated is so large that any effective process of stereo conversion in real time has proved elusive. Fortunately, the complexities of the task have not daunted or stopped various utopians of stereography from making inroads into this most challenging of repurposing technologies. States of the Spatial Art Stereoscopic displays were highly visible at the 2007 Consumer Electronics Show in Las Vegas. Autostereoscopic video displays were much in evidence, with a forty-two-inch LCD 3-D monitor from LG, an intelligent display from The 3D Company (Dubai), and Phillips’s WOWvx professional displays . Autostereoscopic displays were rapidly becoming a mature technology . Almost every one of them had evolved from the classic 1903 U.S. patent by Frederic E. Ives describing a “Parallax Stereogram and Process of Making Same.”1 This was a lenticular autostereoscopic process, and it rep- 284 3-D Revolution Freeman Owens, in a 1936 patent, set forth the fundamental principles of stereo conversion by breaking an image down into various picture units. resented the first really practical method of producing a stereo photograph that did not require glasses for viewing. One of the virtues of the proliferation of autostereoscopic displays was the creation of a need for stereoscopic content. The growth of digital 3-D cinema also creates such a need. These needs can be partially answered by stereo conversion of flat content to three dimensions. In addition to the WOWvx display, Phillips was demonstrating a suite Rebuilding the Z-axis 285 of 3-D content enabling software to convert existing material to stereo with what they call a “2-D plus depth” format using plug-ins for animation software and semiautomated conversion tools for 3-D conversion of 2-D video. The important term here, of course, is “semiautomatic,” because for any stereo conversion procedure to be effective, the intervention of the human hand and eye still remains artistically necessary. The Syntax-Brillian Corporation demonstrated their 3-D Olevia display , a thirty-two-inch LCD HDTV display running content from the Dynamic Digital Depth (DDD) company’s TriDef Vision software that converts existing 2-D broadcast or DVD content to 3-D in real time. DDD stereo conversion technology uses grayscale depth mapping of 2-D imagery that generates left and right eye images, as well as the intermediate views necessary for autostereoscopic displays. DDD, like Phillips, continues to work on a real-time solution to automatic stereo conversion of 2-D moving images. Stereo Foundations With a series of three articles published in the Journal of the Optical Society of America from 1938 to 1941, John T. Rule, professor of engineering graphics at the Massachusetts Institute of Technology, formulated practical techniques for drawing, photographing, and projecting both still and moving stereographic images. In his February 1941 Journal of the Optical Society of America paper, “The Shape of Stereoscopic Images,” Rule wrote that his purpose was “to supply an exact tool for the analysis of stereoscopic effects so that it may become possible to determine the reasons for observable distortions and to predict the results of any proposed optical system.”2 In the absence of a unified literature on the subject of stereoscopy, Rule’s work was primary and significant. In 1939, Rule was granted a U.S. patent for an “Apparatus for Producing Stereographic Drawings.”3 The apparatus, which Rule described as a “space pencil,” could “automatically and accurately” produce “two perspective views of the object drawn, which perspective views are accurately related to each other in a manner corresponding to the relationships of binocular vision.” Rule subsequently worked with John Norling on stereoscopic production of In Tune with Tomorrow, the short 3-D Chrysler film for the 1939–40 World’s Fair in New York, and, along with Edwin H. Land...