Conclusion and Future Work

This paper has dealt with fast and flexible visualization for virtual endoscopy without the use of hardware acceleration. It has discussed the segmentation of important objects, which serve as navigation aid in the endoscopy process, as well as the rendering process. Cell-based first-hit ray casting, a new visualization technique, which is well applicable, for a large spectrum of scenarios in virtual endoscopy, has been introduced. It performs well visualizing the inner surfaces of the investigated organ, as well as surrounding objects. As expected, rendering speed is significantly below that of a hardware-accelerated image-based technique, however, huge gains in flexibility easily make up for that, since rendering speed is still at an acceptable level. Some ideas exist to further improve the performance of cell-based first-hit ray casting. They include, among others, finding an optimal trade-off between effectiveness and security of early scan line termination and improvement of the used data structures to reduce per-macro-cell overhead.