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Interactive navigation system for virtual endoscopy on personal computer
International Congress Series 1230 (2001) 1201 – 1202
Interactive navigation system for virtual endoscopy on personal computer Jinwoo Hwang*, June-Sic Kim, Jae-Seok Kim, In-Young Kim, Sun Il Kim Department of Biomedical Engineering, Hanyang University, Sungdong, P.O. Box 55, Seoul 133-605, South Korea
1. Purpose The most fundamental and effective way to diagnose diseases is to see affected parts directly. But it is very difficult or even impossible in certain cases such as the heart or the vascular brain. Virtual endoscopy provides great advantages to observe organs that one cannot do with conventional endoscopy system. The key ideas of virtual endoscopy are real-time navigation and quality of image. To implement real-time navigation, surfacerendering methods have been generally used. But, it is inferior in quality because it uses intermediate polygonal representation of iso-surface to construct the scenes. For better image quality, volume-rendering methods have been used. But, it takes very long time to render the scene. Our purpose is to develop real-time and high-quality navigation system for virtual endoscopy on a PC environment.
2. Method For real-time and high-quality rendering, a direct volume-rendering method based on 3D texture mapping is used. The 3D texture mapping is now available on any personal computers that have a graphic board supporting OpenGL 1.2. OpenGL defines 3D texture by loading volume data into the texture memory and render it by mapping it to a stack of slices. The textured slices are blended by OpenGL functions resulting in a final image [1]. For the lighting effect, the gradient values of the volume data are rendered. Then, pre-computed color matrix is multiplied [2]. To apply it to the virtual *
Corresponding author. Tel.: +82-2-229-117-13; fax: +82-2-229-659-43. E-mail address: [email protected] (J. Hwang).
0531-5131/01/$ – see front matter D 2001 Elsevier Science B.V. All rights reserved. PII: S 0 5 3 1 - 5 1 3 1 ( 0 1 ) 0 0 2 2 0 - 5
1202
J. Hwang et al. / International Congress Series 1230 (2001) 1201–1202
endoscopy, perspective effect is implemented. Texture bricking technique is used to achieve better rendering speed by loading and rendering the regions only within the range of view volume [1]. To simulate a three-dimensional rotation on the two-dimensional image plane, arcball rotation algorithm is implemented [3].
3. Result MR Angio brain data of 512 512 87 voxels were rendered in Intel PentiumIII 550 Mhz CPU and ATI Radeon 64DDR graphic board. To render 100 frames of image followed by surface of vessel, it took 17.5 s (about six frames per second). Compared to surfacerendered image, it showed a more realistic scene.
4. Conclusion For the high-quality image, real-time volume rendering was only available on high-end graphic workstations. The system we developed in a PC rendered the volumetric data in real-time with high rendering quality. This paper proposes one of the possibilities that the conventional endoscopy might be replaced by the virtual endoscopy in a PC.
References [1] A. Van Gelder, K. Kim, Direct volume rendering with shading via three-dimensional textures, Proceedings of IEEE, Volume Visualization ’96. [2] F. Dachille, K. Kreeger, B. Chen et al., High-quality volume rendering using texture mapping hardware, 1998 Workshop on Graphics Hardware, Lisbon, Portugal. [3] Ken Shoemake, Arcball: a user interface for specifying three-dimensional orientation using a mouse, Proceedings of Graphics Interface ’92.
Interactive navigation system for virtual endoscopy on personal computer Jinwoo Hwang*, June-Sic Kim, Jae-Seok Kim, In-Young Kim, Sun Il Kim Department of Biomedical Engineering, Hanyang University, Sungdong, P.O. Box 55, Seoul 133-605, South Korea
1. Purpose The most fundamental and effective way to diagnose diseases is to see affected parts directly. But it is very difficult or even impossible in certain cases such as the heart or the vascular brain. Virtual endoscopy provides great advantages to observe organs that one cannot do with conventional endoscopy system. The key ideas of virtual endoscopy are real-time navigation and quality of image. To implement real-time navigation, surfacerendering methods have been generally used. But, it is inferior in quality because it uses intermediate polygonal representation of iso-surface to construct the scenes. For better image quality, volume-rendering methods have been used. But, it takes very long time to render the scene. Our purpose is to develop real-time and high-quality navigation system for virtual endoscopy on a PC environment.
2. Method For real-time and high-quality rendering, a direct volume-rendering method based on 3D texture mapping is used. The 3D texture mapping is now available on any personal computers that have a graphic board supporting OpenGL 1.2. OpenGL defines 3D texture by loading volume data into the texture memory and render it by mapping it to a stack of slices. The textured slices are blended by OpenGL functions resulting in a final image [1]. For the lighting effect, the gradient values of the volume data are rendered. Then, pre-computed color matrix is multiplied [2]. To apply it to the virtual *
Corresponding author. Tel.: +82-2-229-117-13; fax: +82-2-229-659-43. E-mail address: [email protected] (J. Hwang).
0531-5131/01/$ – see front matter D 2001 Elsevier Science B.V. All rights reserved. PII: S 0 5 3 1 - 5 1 3 1 ( 0 1 ) 0 0 2 2 0 - 5
1202
J. Hwang et al. / International Congress Series 1230 (2001) 1201–1202
endoscopy, perspective effect is implemented. Texture bricking technique is used to achieve better rendering speed by loading and rendering the regions only within the range of view volume [1]. To simulate a three-dimensional rotation on the two-dimensional image plane, arcball rotation algorithm is implemented [3].
3. Result MR Angio brain data of 512 512 87 voxels were rendered in Intel PentiumIII 550 Mhz CPU and ATI Radeon 64DDR graphic board. To render 100 frames of image followed by surface of vessel, it took 17.5 s (about six frames per second). Compared to surfacerendered image, it showed a more realistic scene.
4. Conclusion For the high-quality image, real-time volume rendering was only available on high-end graphic workstations. The system we developed in a PC rendered the volumetric data in real-time with high rendering quality. This paper proposes one of the possibilities that the conventional endoscopy might be replaced by the virtual endoscopy in a PC.
References [1] A. Van Gelder, K. Kim, Direct volume rendering with shading via three-dimensional textures, Proceedings of IEEE, Volume Visualization ’96. [2] F. Dachille, K. Kreeger, B. Chen et al., High-quality volume rendering using texture mapping hardware, 1998 Workshop on Graphics Hardware, Lisbon, Portugal. [3] Ken Shoemake, Arcball: a user interface for specifying three-dimensional orientation using a mouse, Proceedings of Graphics Interface ’92.