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Accelerated Ray Tracing

  • Akira Fujimoto
  • Kansei Iwata

Abstract

This paper proposes algorithms for dealing with two essential problems encountered in generating continuous-tone images by the ray tracing method: speed and aliasing. These two factors are considered an Achilles’ heel of the method and have been the main cause preventing the method from being widely used. The paper examines previous approaches to the problem and finally proposes a scheme based on the coherency of an auxiliary data structure imposed on the original object domain. Both simple spatial enumeration and a hybrid octree approach were investigated. 3DDDA (3D line generator) was developed for efficient traversing of both structures. It constitutes the essential factor providing a dramatic improvement (order of magnitude) in processing speed in comparison to other known ray tracing methods. In particular, processing time is found to be virtually independent of the number of objects involved in the scene. For a larger number of objects (around 1500), this method actually becomes faster than scan-line methods. In order to remove jags from edges, a scheme for identifying the edge orientation and the distance from a pixel center to the true edge has been implemented. The additional time required for antialiasing depends on the total length of the edges encountered in the scene, but is normally only a fractional addition to the time required to produce such a scene without antialiasing.

Keywords

Computer Graphic Cell Decomposition Control Term Overhead Time Constructive Solid Geometry 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Tokyo 1985

Authors and Affiliations

  • Akira Fujimoto
    • 1
  • Kansei Iwata
    • 1
  1. 1.Graphica Computer CorporationTama, TokyoJapan

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