Transfer Fucntion slides knowledgement : G. Kindlmann

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

Transfer Function

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

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

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

Semi-automatic generation of TF edges

Scatter plot

Analysis

Distance Map

Whole Process

Result : CT Head

Result

Multidimensional Transfer Fucntion

1D vs 2D histogram

Volume rendering using 2D transfer function

Multidimensional transfer function

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

Dual Domain Interaction

Results