## Semi-Automatic Generation of Transfer Functions

for Direct Volume Rendering

### Gordon Kindlmann, James Durkin

## Presentation

Below each slide I've included the text of what I said during the
presentation. I tried to stick to the (memorized) text as much as
possible, but there were some sentences which I forgot; those sentences
have been included here. The last two slides didn't fit into the
time I had, but they are here for the curious. This HTML layout
was created by PowerPoint, with significant help from emacs.
Obviously, when "here" or "this" appears in the text, I was pointing
to something in the slide. You can probably figure out what I was
pointing at, but you'll still be missing my various emotive hand gestures.

__Table of Contents__

- Semi-Automatic Generation of Transfer Functions for Direct Volume Rendering
- Transfer Functions
- Setting transfer function is difficult
- General idea of our approach
- Previous work
- Previous work, continued
- Previous work, continued
- Scope of our approach
- Our boundary model
- Technique based on edge detection ideas
- Opacity functions: data value domain, not spatial domain
- Edge detection in data value domain
- Directional derivatives across boundaries
- Relating f, f', and position
- Relating f, f'', and position
- f - f' and f - f'' parametric plots
- Basic f - f' - f'' inter-relationship
- Histogram volume records f - f'- f'' relationship
- Histogram volume calculation issues
- Sampling along boundary
- Sampling the boundary everywhere
- Directional derivative measurement
- Histogram volume inspection: scatterplots
- Histogram volume inspection, continued
- Review
- To Do
- Position function p(v)
- Boundary emphasis function b(x)
- Synthetic dataset : p(v) result
- b(x), a(v), rendering
- b(x), a(v), rendering, continued
- CT head : p(v) result
- b(x), a(v), rendering
- neuron : p(v) result
- b(x), a(v), rendering
- Two-dimensional opacity functions in use
- Conclusions
- Current/Future Work
- Acknowledgements
- Questions?
- One boundary per value
- Two-dimensional opacity functions