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Fix grammer in README (#67)
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Minor spelling errors fixed
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aksh98md authored Jul 8, 2024
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Expand Up @@ -38,25 +38,25 @@ The most recent version of noisereduce comprises two algorithms:

### Steps of the Stationary Noise Reduction algorithm
1. A spectrogram is calculated over the noise audio clip
2. Statistics are calculated over spectrogram of the the noise (in frequency)
2. Statistics are calculated over spectrogram of the noise (in frequency)
3. A threshold is calculated based upon the statistics of the noise (and the desired sensitivity of the algorithm)
4. A spectrogram is calculated over the signal
5. A mask is determined by comparing the signal spectrogram to the threshold
6. The mask is smoothed with a filter over frequency and time
7. The mask is appled to the spectrogram of the signal, and is inverted
7. The mask is applied to the spectrogram of the signal, and is inverted
*If the noise signal is not provided, the algorithm will treat the signal as the noise clip, which tends to work pretty well*

# Non-stationary Noise Reduction
- The non-stationary noise reduction algorithm is an extension of the stationary noise reduction algorithm, but allowing the noise gate to change over time.
- When you know the timescale that your signal occurs on (e.g. a bird call can be a few hundred milliseconds), you can set your noise threshold based on the assumption that events occuring on longer timescales are noise.
- When you know the timescale that your signal occurs on (e.g. a bird call can be a few hundred milliseconds), you can set your noise threshold based on the assumption that events occurring on longer timescales are noise.
- This algorithm was motivated by a recent method in bioacoustics called Per-Channel Energy Normalization.

### Steps of the Non-stationary Noise Reduction algorithm
1. A spectrogram is calculated over the signal
2. A time-smoothed version of the spectrogram is computed using an IIR filter aplied forward and backward on each frequency channel.
2. A time-smoothed version of the spectrogram is computed using an IIR filter applied forward and backward on each frequency channel.
3. A mask is computed based on that time-smoothed spectrogram
4. The mask is smoothed with a filter over frequency and time
5. The mask is appled to the spectrogram of the signal, and is inverted
5. The mask is applied to the spectrogram of the signal, and is inverted

# Installation
`pip install noisereduce`
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