Abstract

Figure 1: Fig. (a) shows a lens without depth constraint. Here, the pelvis and both arms are distorted by the lens. In (b) the scope of the lens is restricted to the pelvis, i.e. the projection of both arms is not influenced by the lens. Fig. (c) and (d) display an extract of a lens-object tracking sequence. In (c), where the complete skeleton is visible, the lens has been selected by the user to magnify the skull. In (d), where only the skull and the ribcage are visible, the lens has adapted to the position and the size of the skull automatically. In this paper we introduce a novel real-time rendering technique for camera deformations that can be applied to lens distortions and non-realistic projections. Our technique is based on vertex shader textures and presents a hybrid approach working in both, image and object space. As the primal deformation is achieved by a vertex deformation in object space, our technique does not exhibit any artefacts known from pixel-based scaling techniques. Additionally, we present a novel approach for an automatic lensobject tracking that assists the user in manipulating and interacting 3D objects within the scene. Here, we developed a GPU-based technique for fast bounding box determination that is defined by a set of arbitrary vertices. We also discuss different techniques allowing the user to accurately select these vertices in a nonlinearly distorted environment.

Citations