This project is designed for the Audio Pattern Recognition course attended at the University of Milan and it proposes an approach for addressing the Few-Shot Bioacustic Sound Event Detection (SED) task for the DCASE 2023 Challenge.
The Few-Shot-Learning (FSL) framework is followed considering the training as a 5-way 5-shot task. More precisely, transfer learning is used to train models on the larger training set and then finetuning is performed on the validation set of the DCASE challenge using the 5-way 5-shot strategy.

The code has been tested on Ubuntu 22.04 with Python 3.10.

The proposed approach entails the design of a CNN-based module for feature extraction, leveraging the Bayesian Optimisation and HyperBand (BOHB) algorithm [1] for model selection. The selected CNN module is then trained using an online-mining implementation [2] of the Triplet Margin Loss [3] and it is used as feature extractor for a Siamese Network and a Relation Network. The CNN tries to learn useful features in a latent space, which can be visualised as follows:

All networks are trained on features obtained applying Per-Channel Energy Normalisation (PCEN) [4] on Mel-spectrograms extracted from the sound events of interest, while a visualisation of the activation map of the CNN is shown below:

The figures/ folder contains detailed representation of the networks, additional activation maps of the CNN and the plots of the learned feature space.
In the serialized/ folder, training, validation and finetuning metrics are available.