A Stratified Sampling Technique for an Ellipse

Chung-Ming Wang and Nen-Chin Hwang
National Chung Hsing University

This paper appears in issue Volume 9, Number 1.
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Abstract

We present an efficient stratified sampling technique for an ellipse. Our technique provides extensions of previous work for sampling a disk with low distortion; it works for both polar and concentric maps between a square and an ellipse. The mapping preserves adjacency and fractional area, and does not require any numerical computation. As in the previous work, the concentric map demonstrates better performance. Our technique has proven useful in realistic image synthesis using Monte Carlo direct lighting and Monte Carlo path tracing. In conclusion, the proposed technique is stratified, efficient, and feasible for the computer graphics community. Source code is available online.

Author Information

Chung-Ming Wang, National Chung Hsing University, Institute of Computer Science, Room 915, Science Building, 250 Kuo-Kwang Road, Taichung 402, Taiwan, Province of China cmwang@cs.nchu.edu.tw

Nen-Chin Hwang, National Chung Hsing University, Institute of Computer Science, Room 915, Science Building, 250 Kuo-Kwang Road, Taichung 402, Taiwan, Province of China nchuang@cs.nchu.edu.tw

Source Code

The following C source file contains routines to sample the entire ellipse using the concentric map, and the corresponding ellipse-to-square mapping: Ellipse.c (2K HTML text)

BibTeX Entry

@article{WangHwang04,
  author = "Chung-Ming Wang and Nen-Chin Hwang",
  title = "A Stratified Sampling Technique for an Ellipse",
  journal = "journal of graphics, gpu, and game tools",
  volume = "9",
  number = "1",
  pages = "13-22",
  year = "2004",
}