logo

The Visible Human within the VOXEL-MAN Framework


Thomas Schiemann, Ulf Tiede, Karl Heinz Höhne

Institute of Mathematics and Computer Science in Medicine (IMDM),
University Hospital Hamburg-Eppendorf, Germany
e-mail: schiemann@uke.uni-hamburg.de
WWW : http://www.uke.uni-hamburg.de/idv

Introduction

In previous work we have developed a framework for generating volume based 3D interactive atlases from cross-sectional images [4, 7, 10, 14, 15, 16, 18]. These atlases are based on a two layer model of image volumes linked to a semantic network containing descriptive knowledge (see Figure 1). For extraction of the model's contents there is a large set of visualization, exploration, and simulation tools. The pictorial basis of existing VOXEL-MAN atlases are radiologic cross-sectional images. While this has the advantage that anatomy can be linked to radiological imaging, anatomical detail is subject to improvement. The high resolution data sets of the Visible Human project [17] are therefore an ideal basis for this purpose.

Slice Browsing within the VOXEL-MAN brain atlas

Typically the Visible Human images are presented in stacks of orthogonal slices, which can be browsed through. Compared to such simple systems, creation of a real 3D model requires detailed segmentation, which is a huge project due to the vast amount of data and anatomical detail. In our first approach we overcome this problem by registration of the Visible Human with the existing volume based atlas VOXEL-MAN/brain. This procedure introduces anatomical detail from the Visible Human into the radiological environment of VOXEL-MAN/brain, and on the other hand the detailed labelling of VOXEL-MAN can be correlated with the Visible Human [1]. This procedure [12] adds a new functionality to the existing atlas, 3D display of the Visible Human is not possible in this way.

Volume based atlas of the Visible Human Male

The real challenge is, however, the construction of a volume model of the Visible Human, which allows the interactive exploration and the derivation of labelled pictures and animations with realistic visualization. The VOXEL-MAN environment is ready for this. Yet we had to adapt segmentation and rendering to the multi-parametric nature of the data. For segmentation we extended the threshold based methods developed for scalar data [6, 11]. For the color images the intensity threshold range defining an object was replaced by an ellipsoid in RGB-space [13]. The volume visualization algorithms developed previously [2, 3, 5, 8, 9 19] where modified in that the classification defined by the ellipsoid is used for supersampling in the ray-tracing step [20]. The surface colors are texture mapped from the photographic data.

Results

We produced experimental atlases of the Visible Human's head (16 Mvoxels), shoulder (35 Mvoxels), and abdomen (40 Mvoxels). We reduced the in-slice resolution to 1 mm (yielding 1 cmm voxel-size) in order to keep the models in reasonable sizes. We segmented only the major anatomical components so far. It turns out that interactive use of the thus generated atlases is possible at reduced image quality (10-15 seconds per view). The nearly photorealsistic quality achievable with the above described methods must be paid for with longer computation times. For instance Figure 7 with 1254 x 983 pixels took 45 minutes on a DECstation 250 with 266 MHz. To overcome this problem we can precompute QuickTime-VR movies, which allow interaction with 2 degrees of freedom.

Further Information

Further information and some recent papers are found under the URL http://www.uke.uni-hamburg.de/Institutes/IMDM/IDV/ VisibleHuman.html

Acknowledgements

This paper concentrates on the additions made to VOXEL-MAN for incorporating the Visible Human data. Yet VOXEL-MAN is the result of a project to which many co-workers have contributed. Andreas Pommert and Rainer Schubert have designed and implemented the knowledge base and its user interface. Martin Riemer is in charge of the general user interface to which also Bernhard Pflesser and Kay Priesmeyer contributed. Hans-Christian Wulf helped us by generating and providing tools for the movies. Kay Priesmeyer created the HTML version of this paper.

References

1
Höhne, K. H. (Ed.): VOXEL-MAN, Part 1: Brain and Skull, Version 1.1. Springer-Verlag Electronic Media, Heidelberg, 1996. (ISBN 3-540-14584-2).

2
Höhne, K. H., Bernstein, R.: Shading 3D-images from CT using gray level gradients. IEEE Trans. Med. Imaging MI-5, 1 (1986), 45-47.

3
Höhne, K. H., Bomans, M., Pommert, A., Riemer, M., Schiers, C., Tiede, U., Wiebecke, G.: 3D-visualization of tomographic volume data using the generalized voxel-model. Visual Comput. 6, 1 (1990), 28-36.

4
Höhne, K. H., Bomans, M., Riemer, M., Schubert, R., Tiede, U., Lierse, W.: A 3D anatomical atlas based on a volume model. IEEE Comput. Graphics Appl. 12, 4 (1992), 72-78.

5
Höhne, K. H., DeLaPaz, R. L., Bernstein, R., Taylor, R. C.: Combined surface display and reformatting for the 3D-analysis of tomographic data. Invest. Radiol. 22 (1987), 658-664.

6
Höhne, K. H., Hanson, W. A.: Interactive 3D-segmentation of MRI and CT volumes using morphological operations. J. Comput. Assist. Tomogr. 16, 2 (1992), 285-294.

7
Höhne, K. H., Pflesser, B., Pommert, A., Riemer, M., Schiemann, T., Schubert, R., Tiede, U.: A new representation of knowledge concerning human anatomy and function. Nature Med. 1, 6 (1995), 506-511.

8
Höhne, K. H., Riemer, M., Tiede, U.: Viewing operations for 3D-tomographic gray level data. In Lemke, H. U. et al. (Eds.): Computer Assisted Radiology, Proc. CAR '87, Springer-Verlag, Berlin, 1987, 599-609.

9
Pommert A., Bomans M., Höhne K. H.: Volume visualization in magnetic resonance angiography. IEEE Comput. Graphics Appl. 12, 4, (1992), 12-13

10
Pommert, A., Schubert, R., Riemer, M., Schiemann, T., Tiede, U., Höhne, K. H.: Symbolic modeling of human anatomy for visualization and simulation. In Robb, R. A. (Ed.): Visualization in Biomedical Computing 1994, Proc. SPIE 2359. Rochester, MN, 1994, 412-423.

11
Schiemann, T., Bomans, M., Tiede, U., Höhne, K. H.: Interactive 3D-segmentation. In Robb, R. A. (Ed.): Visualization in Biomedical Computing II, Proc. SPIE 1808. Chapel Hill, NC, 1992, 376-383.

12
Schiemann, T., Höhne, K. H., Koch, C., Pommert, A., Riemer, M., Schubert, R., Tiede, U.: Interpretation of tomographic images using automatic atlas lookup. In Robb, R. A. (Ed.): Visualization in Biomedical Computing 1994, Proc. SPIE 2359. Rochester, MN, 1994, 457-465.

13
Schiemann, T., Nuthmann, J., Tiede, U., Höhne, K. H.: Segmentation of the Visible Human for high quality volume based visualization. In Höhne, K. H., Kikinis, R. (Eds.): Visualization in Biomedical Computing, Proc. VBC '96, Lecture Notes in Computer Science 1131, Springer-Verlag, Berlin, 1996, 13-22.

14
Schubert, R., Höhne, K. H., Pommert, A., Riemer, M., Schiemann, T., Tiede, U., Lierse, W.: A new method for practicing exploration, dissection, and simulation with a complete computerized three-dimensional model of the brain and skull. Acta Anat. 150, 1 (1994), 69-74.

15
Schubert R., Höhne K. H., Pommert A., Riemer M., Schiemann T., and Tiede U.: Spatial knowledge representation for visualization of human anatomy and function. In Barrett H. H. and Gmitro A. F. (Eds.): Information Processing in Medical Imaging, Proc. IPMI '93, Lecture Notes in Computer Science 687, Springer-Verlag, Berlin, (1993), 168-181

16
Schubert R., Pommert A., Höhne K. H.: Methods for model-based knowledge representation in anatomy. Annu. Symp. Comput. Appl. Med. Care Proc. SCAMC, New Orleans, LA, (1995), 971 (abstract)

17
Spitzer, V., Ackerman, M. J., Scherzinger, A. L., Whitlock, D.: The Visible Human Male: A Technical Report. J. Am. Med. Inf. Ass. 3, 2 (1996), 118-130.

18
Tiede, U., Bomans, M., Höhne, K. H., Pommert, A., Riemer, M., Schiemann, T., Schubert, R., Lierse, W.: A computerized three-dimensional atlas of the human skull and brain. Am. J. Neuroradiology 14, 3 (1993), 551-559.

19
Tiede, U., Höhne, K. H., Bomans, M., Pommert, A., Riemer, M., Wiebecke, G.: Investigation of medical 3D-rendering algorithms. IEEE Comput. Graphics Appl. 10, 2 (1990), 41-53.

20
Tiede, U., Schiemann, T., Höhne, K. H.: Visualizing the Visible Human. IEEE Comput. Graphics Appl. 16, 1 (1996), 7-9.

   

Figures

Figure 1: Basic framework of the VOXEL-MAN atlases.

Figure 2: Reconstruction of muscular and vascular structures of the head and a magnification of the center portion.

Figure 3: Three illustrations of VOXEL-MAN's ability to cut, map and view different modalities in one rendering.

Figure 4: Two cut plane views of the abdomen.

Figure 5: A view into the Visible Human's stomach and a picture of a real gastroscopic image.

Figure 6: User interface of the experimental atlas VOXEL-MAN/VHP-abdomen.

Figure 7: Two realistic views: the right shoulder with bones, musculature and some major veins; and the torso.

Figure 8: Three red/green stereo views.

Movies: Two QuickTime VR movies.