MedicalVisualization
Transfer Functions
← Local Thresholding | ● | Transfer Functions and Iso Values →
A transfer function, is a generalized concept of color-mapping, where the transfer function assigns physical properties p, such as colors rgb, to scalar values s.
TF(s)=p
Linear transfer functions are realized by a global mapping coefficient:
TF(s)=μ⋅s
The mapping to Hounsfield values is a special case of linear mapping with a scale- and offset-factor:
TF(s)=μ⋅s+o with μ=1000/0.15cm−1,o=−1000
A non-linear assignment is represented as
- threshold function → TFt(s)=1:s>t,0:else
- lookup table
- union of line segments.
Display of transfer functions in the TF Editor as normalized unit function curves, e.g. with gimp “Freehand Curves”:
← Local Thresholding | ● | Transfer Functions and Iso Values →