How does the noise reduction algorithm(s) work in audio?

Question

Audio

What are the noise reduction algorithms in audio?
In particular, I'm interested in how profile noise reduction works. This is, for example, in Audacity and other similar programs.
Do I understand the operation of the algorithm correctly: you need to manually specify the section with audio, where there is nothing but noise. The algorithm makes a frequency analysis for this section and then equalizes throughout the audio, reducing the "loud" frequencies found in the profile.

Answer 1

It works just as you described. Searches the track for a sound that matches the sample and cuts it.
Materiel www.iraj.in/journal/journal_file/journal_pdf/6-162...