Commit 38d9477d authored by Oliver Kirsebom's avatar Oliver Kirsebom
Browse files

updated readme

parent def9139c
......@@ -20,7 +20,8 @@ See the [Step-by-step guide for Windows users](https://gitlab.meridian.cs.dal.ca
# Usage example
To illustrate the usage of the boat detector, we have included an example data set, which
To illustrate the usage of the boat detector, we have included an example data set in the
`assets/` directory, which
consists of 60 short audio recordings, each lasting no more than approximately 10 seconds.
The recordings were made in the span of 1 hour using a broadband hydrophone with a sampling
rate of 20 kHz. The hydrophone was deployed in a shallow bay that is busy with recreational
......@@ -115,8 +116,8 @@ optional arguments:
The main configuration file informs the program about 1) the date-time filename
labeling convetion, 2) the maximum amount of audio data to be processed in a single
batch, and 3) the path to the detector configuration file. In the example above:
```termina
batch, and 3) the path to the detector configuration file.
```terminal
$ more settings.json
{
"date_time_format": "HMS_%H_%M_%S__DMY_%d_%m_%y",
......@@ -127,12 +128,29 @@ $ more settings.json
## Detector configuration file
The
The `detectors/` folder contains two detector configuration files, [fav.json](detectors/fav.json) and [obi.json](detectors/obi.json).
### fav.json
To detect the presence of a boat, the FAV (Frequency Amplitude Variation) detector takes advantage of the fact
that the frequency spectrum of a boat often contains several narrow peaks, which occur at frequencies ranging
from tens of Hz to several hundred Hz. More specifically, the FAV detector computes the Short-Time Fourier
Transform (STFT) of the audio data, searches for narrow peaks, and reports a boat detection if a few such
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).
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.
![](assets/boat.png)
### obi.json
# A little background on the algorithms
"To detect the presence of a boat, we will exploit the fact that the frequency spectrum of a boat often contains several narrow peaks. These peaks occur at frequencies ranging from tens of Hz to several hundred Hz. Thus, our approach will be to compute the frequency spectrum of the audio data, search for narrow peaks, and report a boat detection if a few such peaks are found. We will use a search algorithm similar to the one described in [this paper](https://doi.org/10.1111/2041-210X.13245). 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."
"To detect the presence of a boat, we will
......
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