Interactive directional ambient occlusion and shadow computations for volume ray casting
Resumo
Volume rendering is a widely used technique to visualize 3D scalar data. To enhance visual shape and depth perception, distinct illumination techniques have been proposed, adding different types of lighting effects. In this paper, we explore a new strategy to compute directional ambient occlusion and shadows for volume ray casting to render structured datasets. Our algorithm computes occlusion of traced cones by evaluating Gaussian integrals at discrete samples along the cone axis. The computed occlusion is then used to add directional ambient occlusion effects and to generate shadows. Given the extinction coefficient data volume, we create one extra volume computing representative amplitudes of Gaussian functions. Mipmapping is then used to effectively evaluate Gaussian integrals with different sizes placed along the cone axis, adapting a circle packing approach. We demonstrate that the proposed method delivers a better balance between quality results and performance when compared to previous specialized procedures, with the advantage of combining directional ambient occlusion and shadow generation under the same framework.
Palavras-chave:
Volume rendering, Volumetric illumination, Directional ambient occlusion, Volumetric shadow
Referências
M. Hadwiger, J.M. Kniss, C. Rezk-Salama, D. Weiskopf, K. Engel. Real-Time Volume Graphics. 9781568812663, Taylor & Francis (2006)
N. Max. Optical models for direct volume rendering. IEEE Transactions on Visualization and Computer Graphics, 1 (2) (1995), pp. 99-108
M. Levoy. Display of surfaces from volume data. IEEE Computer Graphics and Applications, 8 (3) (1988), pp. 29-37
J.F. Blinn. Models of light reflection for computer synthesized pictures. Proceedings of the 4th Annual Conference on Computer Graphics and Interactive Techniques, ACM, New York, NY, USA (1977), pp. 192-198
E.C.D. Favera, W. Celes. Ambient occlusion using cone tracing with scene voxelization. 25th SIBGRAPI Conference on Graphics, Patterns and Images (2012), pp. 142-149
C. Crassin, F. Neyret, M. Sainz, S. Green, E. Eisemann. Interactive indirect illumination using voxel cone tracing
Computer Graphics Forum (Proceedings of Pacific Graphics 2011), 30 (7) (2011)
L. Szirmay-Kalos, T. Umenhoffer, B. Tóth, L. Szécsi, M. Sbert. Volumetric ambient occlusion for real-time rendering and games. IEEE Computer Graphics and Applications, 30 (1) (2010), pp. 70-79
G. Papaioannou, M.L. Menexi, C. Papadopoulos. Real-time volume-based ambient occlusion. IEEE Transactions on Visualization and Computer Graphics, 16 (5) (2010), pp. 752-762
F. Hernell, P. Ljung, A. Ynnerman. Local ambient occlusion in direct volume rendering. IEEE Transactions on Visualization and Computer Graphics, 16 (4) (2010), pp. 548-559
T. Ropinski, J. Meyer-Spradow, S. Diepenbrock, J. Mensmann, K. Hinrichs. Interactive volume rendering with dynamic ambient occlusion and color bleeding. Computer Graphics Forum, 27 (2) (2008), pp. 567-576
J. Díaz, P.-P. Vázquez, I. Navazo, F. Duguet. Real-time ambient occlusion and halos with summed area tables
Comput Graph, 34 (4) (2010), pp. 337-350
P. Schlegel, M. Makhinya, R. Pajarola. Extinction-based shading and illumination in gpu volume ray-casting
IEEE Transactions on Visualization and Computer Graphics, 17 (12) (2011), pp. 1795-1802
M. Schott, V. Pegoraro, C. Hansen, K. Boulanger, K. Bouatouch. A directional occlusion shading model for interactive direct volume rendering. Computer Graphics Forum, 28 (2009), pp. 855-862
N. Max, M. Chen. Local and global illumination in the volume rendering integral. Scientific Visualization: Advanced Concepts (2010), pp. 259-274
M. Shih, S. Rizzi, J. Insley, T. Uram, V. Vishwanath, M. Hereld, et al. Parallel distributed, gpu-accelerated, advanced lighting calculations for large-scale volume visualization. 2016 IEEE 6th Symposium on Large Data Analysis and Visualization (LDAV) (2016), pp. 47-55
D. Jönsson, E. Sundén, A. Ynnerman, T. Ropinski. A survey of volumetric illumination techniques for interactive volume rendering. Computer Graphics Forum (2014)
F. Lindemann, T. Ropinski. About the influence of illumination models on image comprehension in direct volume rendering. IEEE Transactions on Visualization and Computer Graphics, 17 (12) (2011), pp. 1922-1931
J. Díaz, T. Ropinski, I. Navazo, E. Gobbetti, P.-P. Vázquez. An experimental study on the effects of shading in 3d perception of volumetric models. Vis Comput, 33 (1) (2017), pp. 47-61
V. S̆oltészová, D. Patel, S. Bruckner, I. Viola. A multidirectional occlusion shading model for direct volume rendering. Computer Graphics Forum, 29 (3) (2010), pp. 883-891
J.G. Magnus, S. Bruckner. Interactive dynamic volume illumination with refraction and caustics. IEEE Transactions on Visualization and Computer Graphics, 24 (1) (2018), pp. 984-993
F.C. Crow. Summed-area tables for texture mapping. Proceedings of the 11th Annual Conference on Computer Graphics and Interactive Techniques, 0-89791-138-5, ACM, New York, NY, USA (1984), pp. 207-212
M. Ament, F. Sadlo, D. Weiskopf. Ambient volume scattering. IEEE Transactions on Visualization and Computer Graphics, 19 (12) (2013), pp. 2936-2945
M. Ament, F. Sadlo, C. Dachsbacher, D. Weiskopf. Low-pass filtered volumetric shadows. IEEE Transactions on Visualization and Computer Graphics, 20 (12) (2014), pp. 2437-2446
J. Wilhelms, A. Van Gelder. A coherent projection approach for direct volume rendering. Proceedings of the 18th Annual Conference on Computer Graphics and Interactive Techniques, 0-89791-436-8, ACM, New York, NY, USA (1991), pp. 275-284
Friedman E. Circles in circles on erich’s packing center. 2019. URL https://www2.stetson.edu/~efriedma/cirincir/.
F. Sans, R. Carmona. A comparison between gpu-based volume ray casting implementations: Fragment shader, compute shader, opencl, and cuda. CLEI Electronic Journal, 20 (2) (2017)
J.H. Krüger, R. Westermann. Acceleration techniques for gpu-based volume rendering. IEEE Visualization, 2003 VIS 2003 (2003), pp. 287-292
N. Max. Optical models for direct volume rendering. IEEE Transactions on Visualization and Computer Graphics, 1 (2) (1995), pp. 99-108
M. Levoy. Display of surfaces from volume data. IEEE Computer Graphics and Applications, 8 (3) (1988), pp. 29-37
J.F. Blinn. Models of light reflection for computer synthesized pictures. Proceedings of the 4th Annual Conference on Computer Graphics and Interactive Techniques, ACM, New York, NY, USA (1977), pp. 192-198
E.C.D. Favera, W. Celes. Ambient occlusion using cone tracing with scene voxelization. 25th SIBGRAPI Conference on Graphics, Patterns and Images (2012), pp. 142-149
C. Crassin, F. Neyret, M. Sainz, S. Green, E. Eisemann. Interactive indirect illumination using voxel cone tracing
Computer Graphics Forum (Proceedings of Pacific Graphics 2011), 30 (7) (2011)
L. Szirmay-Kalos, T. Umenhoffer, B. Tóth, L. Szécsi, M. Sbert. Volumetric ambient occlusion for real-time rendering and games. IEEE Computer Graphics and Applications, 30 (1) (2010), pp. 70-79
G. Papaioannou, M.L. Menexi, C. Papadopoulos. Real-time volume-based ambient occlusion. IEEE Transactions on Visualization and Computer Graphics, 16 (5) (2010), pp. 752-762
F. Hernell, P. Ljung, A. Ynnerman. Local ambient occlusion in direct volume rendering. IEEE Transactions on Visualization and Computer Graphics, 16 (4) (2010), pp. 548-559
T. Ropinski, J. Meyer-Spradow, S. Diepenbrock, J. Mensmann, K. Hinrichs. Interactive volume rendering with dynamic ambient occlusion and color bleeding. Computer Graphics Forum, 27 (2) (2008), pp. 567-576
J. Díaz, P.-P. Vázquez, I. Navazo, F. Duguet. Real-time ambient occlusion and halos with summed area tables
Comput Graph, 34 (4) (2010), pp. 337-350
P. Schlegel, M. Makhinya, R. Pajarola. Extinction-based shading and illumination in gpu volume ray-casting
IEEE Transactions on Visualization and Computer Graphics, 17 (12) (2011), pp. 1795-1802
M. Schott, V. Pegoraro, C. Hansen, K. Boulanger, K. Bouatouch. A directional occlusion shading model for interactive direct volume rendering. Computer Graphics Forum, 28 (2009), pp. 855-862
N. Max, M. Chen. Local and global illumination in the volume rendering integral. Scientific Visualization: Advanced Concepts (2010), pp. 259-274
M. Shih, S. Rizzi, J. Insley, T. Uram, V. Vishwanath, M. Hereld, et al. Parallel distributed, gpu-accelerated, advanced lighting calculations for large-scale volume visualization. 2016 IEEE 6th Symposium on Large Data Analysis and Visualization (LDAV) (2016), pp. 47-55
D. Jönsson, E. Sundén, A. Ynnerman, T. Ropinski. A survey of volumetric illumination techniques for interactive volume rendering. Computer Graphics Forum (2014)
F. Lindemann, T. Ropinski. About the influence of illumination models on image comprehension in direct volume rendering. IEEE Transactions on Visualization and Computer Graphics, 17 (12) (2011), pp. 1922-1931
J. Díaz, T. Ropinski, I. Navazo, E. Gobbetti, P.-P. Vázquez. An experimental study on the effects of shading in 3d perception of volumetric models. Vis Comput, 33 (1) (2017), pp. 47-61
V. S̆oltészová, D. Patel, S. Bruckner, I. Viola. A multidirectional occlusion shading model for direct volume rendering. Computer Graphics Forum, 29 (3) (2010), pp. 883-891
J.G. Magnus, S. Bruckner. Interactive dynamic volume illumination with refraction and caustics. IEEE Transactions on Visualization and Computer Graphics, 24 (1) (2018), pp. 984-993
F.C. Crow. Summed-area tables for texture mapping. Proceedings of the 11th Annual Conference on Computer Graphics and Interactive Techniques, 0-89791-138-5, ACM, New York, NY, USA (1984), pp. 207-212
M. Ament, F. Sadlo, D. Weiskopf. Ambient volume scattering. IEEE Transactions on Visualization and Computer Graphics, 19 (12) (2013), pp. 2936-2945
M. Ament, F. Sadlo, C. Dachsbacher, D. Weiskopf. Low-pass filtered volumetric shadows. IEEE Transactions on Visualization and Computer Graphics, 20 (12) (2014), pp. 2437-2446
J. Wilhelms, A. Van Gelder. A coherent projection approach for direct volume rendering. Proceedings of the 18th Annual Conference on Computer Graphics and Interactive Techniques, 0-89791-436-8, ACM, New York, NY, USA (1991), pp. 275-284
Friedman E. Circles in circles on erich’s packing center. 2019. URL https://www2.stetson.edu/~efriedma/cirincir/.
F. Sans, R. Carmona. A comparison between gpu-based volume ray casting implementations: Fragment shader, compute shader, opencl, and cuda. CLEI Electronic Journal, 20 (2) (2017)
J.H. Krüger, R. Westermann. Acceleration techniques for gpu-based volume rendering. IEEE Visualization, 2003 VIS 2003 (2003), pp. 287-292
Publicado
28/10/2019
Como Citar
CAMPAGNOLO, Leonardo Quatrin; CELES, Waldemar.
Interactive directional ambient occlusion and shadow computations for volume ray casting. In: CONFERENCE ON GRAPHICS, PATTERNS AND IMAGES (SIBGRAPI), 32. , 2019, Rio de Janeiro.
Anais [...].
Porto Alegre: Sociedade Brasileira de Computação,
2019
.
DOI: https://doi.org/10.5753/sibgrapi.2019.9819.
