3D display size matters: Compensating for the perceptual effects of S3D display scaling

Abstract Introduction In recent years the consumer electronics market has been flooded with a variety of S3D products, which rely on a variety of display and image segregation technologies. For each display system, the ideal viewing conditions (eg. viewing angle) can be defined in order to obtain the desired 3D experience. SMPTE and THX [1, 2] have provided specific standards and guidelines for the ideal viewing angle for theatre and television. However, screen dimension 1 is an uncontrolled variable since the same content could be displayed on a mobile autostereoscopic device, 3D monitor, HD 3DTV or in a 3D movie theatre. Adapting a S3D film to a variety of screen sizes is necessary for most, if not all, popular movies if the distributors are to maximize their exposure and therefore earnings. However, unlike 2D film the S3D scaling process is complicated by a variety of 1 The range of viewing distances typically used are correlated with the size of the display, with audiences moving closer as screens get smaller. If field of view is constant it is often the distance that is more important. Since they normally co-vary here we will focus on screen size and related disparity scaling issues, but will point out the role of viewing distance in particular when it is warranted. computational and perceptual issues that can significantly impact the audience experience. As outlined below, the existing approaches to scaling S3D content for a variety of delivery form factors can be divided into two main categories: those applied during acquisition and those applied during postproduction or display. The most common strategy is some combination of pre and post-production approaches. However, inevitably some degree of perceptual and geometric distortion will remain. A better understanding of these distortions and their perceptual consequences will provide S3D content creators with insight and context for using sophisticated scaling approaches based on both acquisition and post-production techniques. This paper will review the principal issues related to S3D content scaling, some of the technical solutions available to content makers/ providers and the perceptual consequences for audiences. Stereoscopic Geometry As was shown by Spottiswood in the early 1950's [3], displaying stereoscopic 3D content at different sizes may dramatically influence the audience's S3D experience. Given the interdependence of acquisition and display parameters; most filmmakers, while trying to protect for different screen dimensions will have a target viewing condition when they begin filming. Figures 1 and 2 depict stereoscopic viewing and acquisition geometry, respectivel