1. Transfer Fucntion slides knowledgement : G. Kindlmann

2. Transfer Function Transfer functions make volume data visible by mapping data values to optical properties volume data

3. Transfer Function

4. Optical Properties –Anything that can be composited with a standard graphics operator (“over”) –Opacity: “opacity functions” Most important –Color Can help distinguish features –Emittance Why don’t we use this more often? –Phong parameters (ka, kd, ks) –Index of refraction

5. Volume rendering with different transfer function Setting transfer function is difficult, unintuitive, and slow

6. Goal Make good renderings easier to come by –Make space of TFs less confusing –Remove excess “flexibility” –Provide one or more of: –Information –Guidance –Semi-automation –Automation

7. Semi-automatic generation of TF edges

8. Scatter plot

9. Analysis

10. Distance Map

11. Whole Process

12. Result : CT Head

13. Result

14. Multidimensional Transfer Fucntion

15. 1D vs 2D histogram

16. Volume rendering using 2D transfer function

17. Multidimensional transfer function

18. Interaction Tools Data Probe Clipping plane Classification Widget –Triangle –rectangle

19. Dual Domain Interaction

20. Results