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Enhancing Depth-Perception with Flexible Volumetric Halos
November/December 2007 (vol. 13 no. 6)
pp. 1344-1351
Volumetric data commonly has high depth complexity which makes it difficult to judge spatial relationships accurately. There are many different ways to enhance depth perception, such as shading, contours, and shadows. Artists and illustrators frequently employ halos for this purpose. In this technique, regions surrounding the edges of certain structures are darkened or brightened which makes it easier to judge occlusion. Based on this concept, we present a flexible method for enhancing and highlighting structures of interest using GPU-based direct volume rendering. Our approach uses an interactively defined halo transfer function to classify structures of interest based on data value, direction, and position. A feature-preserving spreading algorithm is applied to distribute seed values to neighboring locations, generating a controllably smooth field of halo intensities. These halo intensities are then mapped to colors and opacities using a halo profile function. Our method can be used to annotate features at interactive frame rates.

[1] A. Appel, F. J. Rohlf, and A. J. Stein, The haloed line effect for hidden line elimination. In Proceedings of ACM SIGGRAPH 1979, pages 151–157, 1979.
[2] U. Behrens and R. Ratering, Adding shadows to a texture-based volume renderer. In Proceedings of IEEE Symposium on Volume Visualization 1998, pages 39–46, 1998.
[3] P. Cavanagh, Pictorial art and vision. In R. A. Wilson and F. C. Keil, editors, The MIT Encyclopedia of the Cognitive Sciences, pages 644–646. MIT Press, Cambridge, MA, 1999.
[4] B. Csébfalvi, L. Mroz, H. Hauser, A. König, and M. E. Gröller, Fast visualization of object contours by non-photorealistic volume rendering. Computer Graphics Forum, 20 (3): 452–460, 2001.
[5] P. Desgranges, K. Engel, and G. Paladini, Gradient-free shading: A new method for realistic interactive volume rendering. In Proceedings of Vision, Modeling, and Visualization 2005, pages 209–216, 2005.
[6] H. Hauser, L. Mroz, G.-I. Bischi, and M. E. Gröller, Two-level volume rendering. IEEE Transactions on Visualization and Computer Graphics, 7 (3): 242–252, 2001.
[7] E. R. S. Hodges, editor. The Guild Handbook of Scientific Illustration. John Wiley & Sons, Hoboken, NJ, 2nd edition, 2003.
[8] V. Interrante and C. Grosch, Strategies for effectively visualizing 3D flow with volume LIC. In Proceedings of IEEE Visualization 1997, pages 421–424, 1997.
[9] M. Kersten, J. Stewart, N. Troje, and R. Ellis, Enhancing depth perception in translucent volumes. IEEE Transactions on Visualization and Computer Graphics, 12 (5): 1117–1124, 2006.
[10] G. Kindlmann, R. Whitaker, T. Tasdizen, and T. Möller, Curvature-based transfer functions for direct volume rendering: Methods and applications. In Proceedings of IEEE Visualization 2003, pages 513–520, 2003.
[11] J. Kniss, G. Kindlmann, and C. Hansen, Multidimensional transfer functions for interactive volume rendering. IEEE Transactions on Visualization and Computer Graphics, 8 (3): 270–285, 2002.
[12] J. Kniss, S. Premoze, C. Hansen, P. Shirley, and A. McPherson, A model for volume lighting and modeling. IEEE Transactions on Visualization and Computer Graphics, 9 (2): 150–162, 2003.
[13] J. Krüger, J. Schneider, and R. Westermann, ClearView: An interactive context preserving hotspot visualization technique. IEEE Transactions on Visualization and Computer Graphics, 12 (5): 941–948, 2006.
[14] C. H. Lee, X. Hao, and A. Varshney, Geometry-dependent lighting. IEEE Transactions on Visualization and Computer Graphics, 12 (2): 197–207, 2006.
[15] M. Levoy, Display of surfaces from volume data. IEEE Computer Graphics and Applications, 8 (3): 29–37, 1988.
[16] J. Loviscach, Stylized haloed outlines on the GPU. ACM SIGGRAPH 2004 Poster, 2004.
[17] T. Luft, C. Colditz, and O. Deussen, Image enhancement by unsharp masking the depth buffer. In Proceedings of ACM SIGGRAPH 2006, pages 1206–1213, 2006.
[18] E. B. Lum and K.-L. Ma, Lighting transfer functions using gradient aligned sampling. In Proceedings of IEEE Visualization 2004, pages 289–296, 2004.
[19] N. Max, Optical models for direct volume rendering. IEEE Transactions on Visualization and Computer Graphics, 1 (2): 99–108, 1995.
[20] Z. Nagy, J. Schneider, and R. Westermann, Interactive volume illustration. In Proceedings of Vision, Modeling, and Visualization 2002, pages 497–504, 2002.
[21] Y. Ostrovsky, P. Cavanagh, and P. Sinha, Perceiving illumination inconsistencies in scenes. Perception, 34 (11): 1301–1314, 2005.
[22] P. Rheingans and D. S. Ebert, Volume illustration: Nonphotorealistic rendering of volume models. IEEE Transactions on Visualization and Computer Graphics, 7 (3): 253–264, 2001.
[23] F. Ritter, C. Hansen, V. Dicken, O. Konrad, B. Preim, and H.-O. Peitgen, Real-time illustration of vascular structures. IEEE Transactions on Visualization and Computer Graphics, 12 (5): 877–884, 2006.
[24] G. Rong and T.-S. Tan, Jump flooding in GPU with applications to voronoi diagram and distance transform. In Proceedings of ACM Symposium on Interactive 3D Graphics and Games 2006, pages 109–116, 2006.
[25] A. J. Stewart, Vicinity shading for enhanced perception of volumetric data. In Proceedings of IEEE Visualization 2003, pages 355–362, 2003.
[26] N. A. Svakhine and D. S. Ebert, Interactive volume illustration and feature halos. In Proceedings of the Pacific Conference on Computer Graphics and Applications 2003, pages 347–354, 2003.
[27] I. Viola, A. Kanitsar, and M. E. Gröller, Importance-driven feature enhancement in volume visualization. IEEE Transactions on Visualization and Computer Graphics, 11 (4): 408–418, 2005.
[28] A. Wenger, D. F. Keefe, and S. Zhang, Interactive volume rendering of thin thread structures within multivalued scientific data sets. IEEE Transactions on Visualization and Computer Graphics, 10 (6): 664–672, 2004.
[29] R. Yagel, A. Kaufman, and Q. Zhang, Realistic volume imaging. In Proceedings of IEEE Visualization 1991, pages 226–231, 1991.
[30] X. Yuan and B. Chen, Illustrating surfaces in volume. In Proceedings of Joint IEEE/EG Symposium on Visualization 2004, pages 9–16, 2004.
[31] J. Zhou, A. Döring, and K. D. Tönnies, Distance based enhancement for focal region based volume rendering. In Proceedings of Bildverarbeitung für die Medizin 2004, pages 199–203, 2004.

Index Terms:
Volume rendering, illustrative visualization, halos
Citation:
Stefan Bruckner, Eduard Gröller, "Enhancing Depth-Perception with Flexible Volumetric Halos," IEEE Transactions on Visualization and Computer Graphics, vol. 13, no. 6, pp. 1344-1351, Nov.-Dec. 2007, doi:10.1109/TVCG.2007.70555
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