Apparent stereo: the Cornsweet illusion can enhance perceived depth

Abstract

It is both a technical and an artistic challenge to depict three-dimensional content using stereo equipment and a flat two-dimensional screen. On the one hand, the content needs to fit within the limits of a given display technology and at the same time achieve a comfortable viewing experience. Given the technological advances of 3D equipment, especially the latter increases in importance. Modifications to stereo content become necessary that aim at flattening or even removing binocular disparity to adjust the 3D content to match the comfort zone in which the clash between accommodation and vergence stays acceptable. However, applying such modifications can lead to a reduction of crucial depth details. One promising direction is backwardcompatible stereo, for which the disparity is low enough that overlaid stereo pairs seem almost identical. It builds upon the Craik-O'Brien-Cornsweet effect, a visual illusion, which uses so-called Cornsweet profiles to produce a local contrast that leads to a perceived brightness increase. Similarly, Cornsweet profiles in disparity can lead to an illusion of depth. Applying them skilfully at depth discontinuities allows for a reduction of the overall disparity range to ensure a comfortable yet convincing stereo experience. The present work extends the previous idea by showing that Cornsweet profiles can also be used to enhance the 3D impression. This operation can help in regions where the disparity range was compressed, but also to emphasize parts of a scene. A user study measures the performance of backward-compatible stereo and our disparity enhancement.

3d+2dtv

“…Didyk et al have also considered the problem of displaying a 3D image to a viewer wearing glasses while creating an acceptable 2D image for those without glasses, which they refer to as "backward compatible stereo" [Didyk et al 2011[Didyk et al , 2012. They reduce the disparity between objects in the left and right images to a minimal threshold, preferentially retaining high-frequency components.…”

“…We compared our prototype to Didyk et al's "backwardcompatible stereo," which improves the 2D viewing experience by reducing stereo disparity to the minimum that still maintains a perception of depth for 3D viewers [Didyk et al 2011[Didyk et al , 2012. The original stereo image is shown in Figure 10(a).…”

Kinetic depth images: flexible generation of depth perception

“…However, this will compress both important and unimportant regions of the scene uniformly. Extensive amount of research has been conducted in visual saliency and perceptual enhancements [9,10,16,20,21,23,24,28,29,57]; however, use of motion makes our situation unique. We want the salient regions of the scene to occupy a larger share of the depth range while compressing non-salient regions and artifacts.…”

Towards a free viewpoint and 3D intensity adjustment on multi-view display

“…Being inside this zone is then mandatory to ensure a correct acceptation. Alternative solutions have been proposed using for instance the Cornsweet illusion to reduce the depth [10]. In our application, since new views must be generated, it is possible to optimize the global depth budget to always satisfy this comfort zone.…”