VTK Volume Visualization

MVL Homepage Department of Computer Engineering and Computer Science

Contact Information:

Jesse Whitlock
Department of Computer Engineering and Computer Science
University of Missouri-Columbia
Columbia, MO 65211

K. Palaniappan
Department of Computer Engineering and Computer Science
University of Missouri-Columbia
Columbia, MO 65211

3D Model Generation From Biomedical Data

Using the Visualization ToolKit

VTK is a software system for 3D computer graphics and visualizaion. It uses a C++ class library and a Tcl implementation based on the class information. The use of Tcl scripts adversly effects performance, but can speed up development because time-consuming compilations are not necessary. Several surface generation algorithms have been implemented, and the system uses OpenGL to implement the graphics funcionalities. Given the power, versitility, and portability of this package, its growing popularity is hardly surprising.

VTK homepage

Two sets of data were used in this project. The original objective of the project was to create a surface model from 8-bit CT data from which the left ventricle had been segmented out by Li Fan, a Ph.D. student at MU. This model would be compaired with a surface model created by extracting isosurfaces from the raw data. Because of the contrast agent used to highlight the left ventricle, this should not have been an insurmountable task. However, it is proposed that the 8 bit data, which only provides for 256 different density values for all points in the data, prevented the simple extraction of the isosurface. What was obtained by using procedures standard to VTK was a jumbled collection of voxels that were not necessarily a part of or adjacent to the LV because of the limited amount of varience dictaed by the datatype. Because of these limitations, a set of 16 bit data was used to illustrate the proper method of extracting a particular isosurface, in this case corresponding to bone (CT number ~1150).

Notice the errors in segmentation that lead to the partial disks that are not flush with the side of the model.

View model generated from presegmented data (View #1)

Presegmented View #2

Presegmented View #3

Notice the subtraction of the soft tissue leading to a hollow spinal cord pathway.

View model generated from raw data isosurface(View #1)

Isosurface View #2

Isosurface View #3

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