Geometrical Analysis of Puppet Theater and Cardboard Effects in Stereoscopic Images

Abstract

Research has continued on the shooting conditions for production of natural stereoscopic images. In this paper, we present an analysis of the conversion of images from real space into stereoscopic images from the point of view of the geometrical relationships of the binocular parallax. In particular, the differences in conversion between images shot by a parallel camera configuration and those shot by a toed-in camera configuration are discussed, taking into consideration the effects of the horizontal shift between left and right images. We also derived some simple equations relating to the distortions peculiar to stereoscopic images, such as the puppet theater effect and the cardboard effect. According to these equations, stereoscopic images shot using a parallel camera configuration do not produce the puppet theater effect while a toed-in camera configuration may produce the effect. Both camera configurations may produce the cardboard efffect.