Table 1 Compositing methods in FluoRender

Front-to-back

\( {C}_{out}=\left(1-{\alpha}_{dest}\right)\bullet {C}_{source}+{C}_{dest} \)

Blends semitransparent layers from front to back. Also used for ray casting

Direct volume rendering (DVR) for one channel

Back-to-front

\( {C}_{out}={\alpha}_{source}\bullet {C}_{source}+\left(1-{\alpha}_{source}\right)\bullet {C}_{dest} \)

Blends semitransparent layers from back to front

Layered channel- intermixing mode

Addition

\( {C}_{out}={C}_{source}+{C}_{dest} \)

Sums input and existing intensity values

Composite channel- intermixing mode;

compositing operations between slices in depth mode;

visualization of selected structures

Maximum intensity

\( {C}_{out}= MAX\left({C}_{source},{C}_{dest}\right) \)

Finds the maximum intensity value from the input and existing values

MIP rendering for one channel

Multiplication

\( {C}_{out}={C}_{source}\bullet {C}_{dest} \)

Multiplies the intensity value of the input by the existing value. Also called modulation

Shading and shadow effects