Training neural audio classifiers with few data

We investigate supervised learning strategies that improve the training of neural network audio classifiers on small annotated collections. In particular, we study whether (i) a naive regularization of the solution space, (ii) prototypical networks, (iii) transfer learning, or (iv) their combination, can foster deep learning models to better leverage a small amount of training examples. To this end, we evaluate (i-iv) for the tasks of acoustic event recognition and acoustic scene classification, considering from 1 to 100 labeled examples per class. Results indicate that transfer learning is a powerful strategy in such scenarios, but prototypical networks show promising results when one does not count with external or validation data.

This repository contains code to reproduce the results of our arXiv paper.

Reference:

@article{pons2018training,
    author = {Pons, J. and Serr\`a, J. and Serra, X.},
    title = {Training neural audio classifiers with few data},
    journal = {ArXiv},
    volume = {1810.10274},
    year = 2018,
    }

Reproduce our results

Download the data:

Download US8K dataset, and ASC-TUT dataset (dev-set / eval-set).

Installation:

Create a python 3 virtual environment and install dependencies pip install -r requirements.txt

Install tensorflow for CPU pip install tensorflow or for CUDA-enabled GPU pip install tensorflow-gpu

Be sure to have ffmpeg installed, as well.

Preprocess the data:

To preprocess the data, first set some config_file.py variables:

• DATA_FOLDER, where you want to store all your intermediate files (see folders structure below).
• config_preprocess['audio_folder'], where your dataset is located.

Preprocess the data running python preprocess.py asc_spec. Note asc_spec config option is defined in config_file.py

After running preprocess.py, spectrograms are in ../DATA_FOLDER/audio_representation/asc__time-freq/

Warning! Rename index_0.tsv to index.tsv. This is because this script is parallelizable.

Regularized deep learning results:

Set config_sl dictionary in config_file.py, and run CUDA_VISIBLE_DEVICES=0 python sl_train.py spec

Once training is done, the resulting model is stored in ../DATA_FOLDER/experiments/fold_0_1541174334/

To evaluate the model, run CUDA_VISIBLE_DEVICES=0 python sl_evaluate.py fold_0_1541174334

Prototypical networks results:

Set config_proto dictionary in config_file.py, and run CUDA_VISIBLE_DEVICES=0 python proto.py spec

Transfer learning results:

We also study the effectiveness of transfer learning. For that, we use a VGG model pre-trained with Audioset, a dataset conformed by 2 M YouTube audios. This model is available online.

For being able to run transfer learning experiments, you just need to download the VGGish model checkpoint vggish_model.ckpt, and copy it to /src.

Then, you can run transfer_proto.py following the same logic as in proto.py. Now via setting config_proto dictionary in config_file.py

And you can also run transfer_train.py and transfer_evaluate.py following the same logic as in transfer_sl.py and transfer_sl.py. Now via setting config_transfer_proto dictionary in config_file.py

Scripts

Configuration and preprocessing scripts:

• config_file.py: file with all configurable parameters.
• preprocess.py: pre-computes and stores the spectrograms.

Scripts for regularized deep learning models experiments:

• sl_train.py: run it to train your model. First set config_sl in config_file.py
• sl_evaluate.py: run it to evaluate the previously trained model.
• models_sl.py: script where the architectures are defined.

Scripts for prototypical networks experiments:

• proto.py: run it to reproduce our prototypical networks' results. First set config_proto in config_file.py
• models_proto.py: script where the architectures are defined.

Scripts for transfer learning experiments:

• transfer_train.py: run it to reproduce our transfer learning (with finetuning) results. First set config_transfer in config_file.py
• transfer_evaluate.py: run it to evaluate the previously trained model.
• transfer_proto.py: run it to reproduce our prototypical networks' results. First set config_transfer_proto in config_file.py

Auxiliar scripts:

• knn_audioset.py: run it to reproduce our nearest-neigbour Audioset results.
• knn_mfcc.py: run it to reproduce our nearest-neigbour MFCCs results.
• shared.py: auxiliar script with shared functions that are used by other scripts.
• vggish_input.py,vggish_params.py,vggish_slim.py,mel_features.py,vggish_model.ckpt: auxiliar scripts for transfer learning experiments.

Folders structure

• /src: folder containing previous scripts.
• /aux: folder containing auxiliar additional scripts. These are used to generate the index files in /data/index/.
• /data: where all intermediate files (spectrograms, results, etc.) will be stored.
• /data/index/: indexed files containing the correspondences between audio files and their ground truth.

When running previous scripts, the following folders will be created:

• ./data/audio_representation/: where spectrogram patches are stored.
• ./data/experiments/: where the results of the experiments are stored.