understanding noise level controls

[tko]

I'm trying to understand noise level controls on an intuitive level. The manual states:

"The noise level controls determine which image elements are
considered noise. . . When the level controls are set differently, the noise
level estimations are raised or lowered accordingly."

Can I think of the noise level controls as a "threshold" that must be crossed noise filtering is applied? Kind of like the threshold setting in PS unsharp mask? How does NI determine whether an element is "noise" or not?

[NITeam]

Can I think of the noise level controls as a "threshold" that must be crossed noise filtering is applied? Kind of like the threshold setting in PS unsharp mask?

Yes, a noise level (estimation) can be considered as a kind of threshold. However the difference between noise levels in NI and threshold in PS unsharp mask is that NI noise reduction is applied to image elements below the noise level, while PS sharpening is applied to image elements above the threshold. Because of this calling noise levels 'thresholds' may produce confusion.

How does NI determine whether an element is "noise" or not?

If an element is noise-like and its strenght is below noise level then it is most likely noise. This is difficult to explain without use of math formulae.

Vlad