Commit 275f5408 authored by Oliver Kirsebom's avatar Oliver Kirsebom
Browse files

updated readme

parent 6b532cc0
......@@ -140,14 +140,29 @@ Transform (STFT) of the audio data, searches for narrow peaks, and reports a boa
peaks are found. The peak search algorithm is similar, though not identical, to the one described in
[this paper](https://doi.org/10.1111/2041-210X.13245).
The performance of the FAV detector can be optimized by adjustable the parameters found in the [fav.json](detectors/fav.json)
configuration files. While this file contains many parameters, the most relevant are the `threshold` parameter (found in
the `fav_config` section) and the `height` parameter (found in the `detect_config` section). The former determines how sharp and tall
a frequency peak must be to be counted as a peak, while the latter determines how many such peaks must be present at given
instant to produce a boat detection.
### obi.json
The OBI (Octave Band Intensity) detector, on the other hand, detects boats by looking for variations in the
sound intensity within the 2nd, 3rd, and 4th octave band, centered at 125 Hz, 250 Hz, and 500Hz.
The performance of the OBI detector can be optimized by adjustable the parameters found in the [obi.json](detectors/obi.json)
configuration files. While this file contains many parameters, the most relevant are the `prominence` and `multiplicity`
parameters (found in the `detect_config` section). The former determines how prominent the increase in the
sound intensity must be to be counted as signal, while the latter determines in how many octave bands such
a signal must be detected to produce a boat detection.
Below, you see the spectrogram of a 10-second long audio recordering containing noise from a boat.
Narrow peaks in the frequency spectrum are seen as sharp horizontal lines in the spectrogram, visible
at about 20 Hz, 50 Hz, 95 Hz, and 145 Hz.
at about 20 Hz, 50 Hz, 95 Hz, and 145 Hz, as well as an overall increase of sound intensity, especially
in the third octave band centered at 250 Hz.
![](assets/boat.png)
### obi.json
# A little background on the algorithms
......
......@@ -8,6 +8,9 @@
"window_size": "1 min",
"step_size": "1 min"
},
"fav_config": {
"threshold": "3.0"
},
"spectrogram": {
"rate": "4000 Hz",
"window_size": "1.0 s",
......@@ -22,7 +25,6 @@
"peak_finding_config": {
"separation": "2 minutes",
"prominence": "2.0",
"multiplicity": "1",
"height": "2"
}
}
......
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