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I'm trying to filter noise from an audio signal. The signal was and is going to be recorded in a city environment which always contains some white/pink noise.

At this moment I'm using two options to filter the noise. Spectral Subtraction algorithm and Wiener filter.

I'm assuming the initial samples are noise only and that's how the filter starts subtracting noise, but I can't make this assumption at all times. I have to automatically detect when it's noise and when it's not.

My audio signal

I'm using Matlab btw.

If anyone has any sugestion... thanks

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    $\begingroup$ You can use Voice Activity Detection(VAD) algorithm for the required task. the choice of VAD algorithm depends on the characteristics/features of noise present in your recordings. If speech is supposed to have very high energy(magnitude) in comparison to noise than you can directly use some threshold on energy(to be calculated frame wise of length around 20 ms) and declare corresponding frames as noise or speech. $\endgroup$
    – Arpit Jain
    Jun 10, 2016 at 11:58
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    $\begingroup$ Carlos, welcome to DSP.SE! This is an on-topic question, but it may be a little general as asked. Can you expand on why you're asking the question if At this moment I'm using two options to filter the noise. ? What is wrong with the two options you have? $\endgroup$
    – Peter K. ♦
    Jun 10, 2016 at 12:21
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    $\begingroup$ ok, sorry for not being clear x) . I'm assuming, in these two options, that I have a noise sample before I run the algorithm. but when the algorithm is runing it will not know what is noise at the begining. The algorithm has to run in real time. So no offline verification of what is a sample of noise only. the algorithm (distributed through a series of microphones along a location in a city) has to adapt to each point of the city and identify samples that are only noise, so that it can then run the noise filters (Spectral Subtraction or Wiener) $\endgroup$
    – Carlos_Rei
    Jun 10, 2016 at 16:44
  • $\begingroup$ @arpit I'm not sure if VAD is right in this situation. I've got to detect sound events that are not speech as well. using a threshold it might work in a few , maybe most, cases , but it will eliminate some events that might be relevant for me. $\endgroup$
    – Carlos_Rei
    Jun 10, 2016 at 16:50
  • $\begingroup$ @Carlos_Rei do you want to detect all the events except ambient noise ? $\endgroup$
    – Arpit Jain
    Jun 11, 2016 at 9:05

1 Answer 1

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From here.

BRIL Noise Reduction | DSP ALGORITHMS. BRIL is a high quality blind noise reduction algorithm. It takes as its input a noisy audio or voice signal and tries to estimate and reduce the noise in the input signal without distorting the audio. In most cases the input signal is recorded by a single-microphone.

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    $\begingroup$ Lokman, copying and pasting material from another website is plagiarism unless you link to it and/or give appropriate attribution. $\endgroup$
    – Peter K. ♦
    Jun 2 at 18:26
  • $\begingroup$ To complement @PeterK.'s comment, providing link-only answers is not useful. Most probably the OP could very well find that link themselves simply by Googling. SE is a Q&A site and answers should be as self-contained and stand-alone as possible. $\endgroup$
    – ZaellixA
    Jun 2 at 19:15
  • $\begingroup$ Yes, I presented this algorithm from websites on Google pages, and it's not considered theft, because this information is available on all the pages. It's also an answer, not a scientific article. I didn't assign this work to myself. I wanted to give the right answer after the search, so that I could engage in the site and work and benefit from the site because of its selection and offer questions and answers, especially in my research field, so that it would be useful. $\endgroup$
    – Lokman Alhakim
    Jun 4 at 1:26

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