Unsupervised Feature Learning for Music and Audio

For my PhD thesis, I explored unsupervised feature learning for musical data and applied them to music classification, annotation and transcription.

Feature Learning for Music Classification and Annotation

This presents an effective data processing pipeline to find feature representations from musical signals using unsupervised learning algorithms. This learning-based feature representations were utilized in music genre classification, annotation (a.k.a tagging) and text-based retrieval tasks.

SAFVY! - Real-Time Music Tagging Visualizer

A real-time music tagging demo that shows data/feature representations as well as estimated tags that describes music in semantic levels (e.g. genre, emotion, instrument, voice quality and other semantic words)

Polyphonic Piano Transcription Using Learned Audio Features

We applied the feature learning idea to polyphonic piano transcription. Based on a classification approach (i.e. a binary classifier determines the presence of a single note), we pre-trained a neural networks in an unsupervised way and then fine-tuned the networks using the errors which are simultaneously propagated from multiple note classifiers.
[paper] [poster]

Sound Representation and Recognition

I spent some time working on new sound representation and recognition methods using probabilistic latent component analysis (PLCA), which is a probabilistic version of non-negative matrix factorization (NMF).

Sound Recognition in Mixture

This presents a method for recognizing sound sources in a mixture. The method is based on a source separation idea using the PLCA but estimates relative proportions of the mixture without separating the sources.

Super-Resolution Spectrogram

The short-time Fourier transform (STFT) based spectrogram intrinsically has a trade-off in time and frequency resolution when it is displayed as a 2-D time-frequency representation. We propose an idea to achieve high resolutions in both time and frequency using PLCA.

Sound Synthesis

Sound synthesis is my longtime favorite. I love to learn and explore various sound synthesis techniques and sound design using them. This introduces my research work that I spent quite a while.

Virtual Analog Oscillators

With Vesa Välimäki and Jussi Pekonen at Aalto University, I came up with several different algorithms to efficiently generate bandlimited (anti-aliasing) oscillators, which are used in virtual analog synthesizers. This briefly introduces a class of algorithms among them.

Spatial Audio

ThreeDee: Binaural Sound Processor

This shows a 3-D sound processing demo working in real-time. It uses head-related transfer functions (HRTFs) to synthesize binaural sounds from monaural sources. We measured the HRTFs from human subjects and efficiently modeled them using their minimum-phase characteristic.