A Curved Ray Camera for Handling Occlusions through Continuous Multiperspective Visualization

Most images used in visualization are computed with the planar pinhole camera. This classic camera model has important advantages such as simplicity, which enables efficient software and hardware implementations, and similarity to the human eye, which yields images familiar to the user. However, the planar pinhole camera has only a single viewpoint, which limits images to parts of the scene to which there is direct line of sight. In this paper we introduce the curved ray camera to address the single viewpoint limitation. Rays are C1-continuous curves that bend to circumvent occluders. Our camera is designed to provide a fast 3-D point projection operation, which enables interactive visualization. The camera supports both 3-D surface and volume datasets. The camera is a powerful tool that enables seamless integration of multiple perspectives for overcoming occlusions in visualization while minimizing distortions.

1 Introduction

Almost all images used in visualization are computed with a planar pinhole camera (PPC). One reason for this is that the PPC models the human eye well, producing images that resemble what users would see if they were actually looking at the dataset to be visualized. Another reason is simplicity: software and hardware implementations of PPC rendering algorithms allow visualizing complex 3-D datasets at interactive rates. However, the simplicity of the PPC model also brings three important limitations. First, the PPC has a limited field of view. Second, the sampling rate of the PPC is uniform over its entire field of view. Third, the PPC has only a single viewpoint, i.e. the pinhole where all rays converge.