Real Time Ray Tracing for Augmented Reality

This paper introduces a novel graphics rendering pipeline applied to augmented reality, based on a real time ray tracing paradigm. Ray tracing techniques process pixels independently from each other, allowing an easy integration with image-based tracking techniques, contrary to traditional projection-based rasterization graphics systems, e.g. OpenGL. Therefore, by associating our highly optimized ray tracer with an augmented reality framework, the proposed pipeline is capable to provide high quality rendering with real time interaction between virtual and real objects, such as occlusions, soft shadows, custom shaders, reflections and self-reflections, some of these features only available in our rendering pipeline. As proof of concept, we present a case study with the ARToolKitPlus library and the Microsoft Kinect hardware, both integrated in our pipeline. Furthermore, we show the performance and visual results in high definition of the novel pipeline on modern graphics cards, presenting occlusion and recursive reflection effects between virtual and real objects without the latter ones needing to be previously modeled when using Kinect. Furthermore, an adaptive soft shadow sampling algorithm for ray tracing is presented, generating high quality shadows in real time for most scenes.