Ray path categorization

TL;DR: An algorithm that divides rays into equivalence classes, or categories is presented, which is generated during the rendering process and used to determine edges in the resulting image.

Abstract: Edge detection and image segmentation algorithms usually operate on an image to extract geometrical information based on pixel colors. For ray-traced images, the presence of geometrical information on the scene from which the image was rendered allows for a completely different approach. We present an algorithm that divides rays into equivalence classes, or categories. The category information is generated during the rendering process and used to determine edges in the resulting image. Detected edges can later be used to help determine areas subject to aliasing. Little effort is needed to implement the described algorithms over an existing ray tracer. Furthermore, the extra computational and memory requirements are modest.