Auditory Spectrum-Based Pitched Instrument Onset Detection

In this paper, a method for onset detection of music signals using auditory spectra is proposed. The auditory spectrogram provides a time-frequency representation that employs a sound processing model resembling the human auditory system. Recent work on onset detection employs DFT-based features describing spectral energy and phase differences, as well as pitch-based features. These features are often combined for maximizing detection performance. Here, the spectral flux and phase slope features are derived in the auditory framework and a novel fundamental frequency estimation algorithm based on auditory spectra is introduced. An onset detection algorithm is proposed, which processes and combines the aforementioned features at the decision level. Experiments are conducted on a dataset covering 11 pitched instrument types, consisting of 1829 onsets in total. Results indicate that auditory representations outperform various state-of-the-art approaches, with the onset detection algorithm reaching an F-measure of 82.6%

Music Transcription Within Irish Traditional Music

Transcribing Irish traditional music is an open-field of research. The oral transmission of the music between generations explains the lack of transcription until recent times. The music can be played solo, which permits the player to exploit the variety of ornamentation types, in unison, and also with the accompaniment of a harmonic instrument. Different signal processing applications for transcribing Irish traditional music are presented in this thesis, including onset, ornamentation and pitch detection. An onset detection system which focuses on the characteristics of the tin whistle within Irish traditional music is first presented. The tin whistle is a good example of the features of Irish traditional music, and the detection of its onset encounters all the problems associated with onset detection identified in the literature review. An extension of this method is also implemented in an effort to detect the most common types of ornamentation, which has not been attempted to date. Existing onset detectors utilise energy and/or phase information to detect onsets. A novel onset detector, which focuses on the harmonicity of the signal to detect the onsets by using comb filters, is presented. This methods overcomes the difficulties encountered by existing onset detection approaches in respect of signal modulations and detection of slow onsets. Finally, a further comb filter based method is utilised to detect the triads played by a harmonic accompaniment. A set of results is presented for the four methods, followed by a commentary and explanation of the novel contributions

Correction system for polyphonic piano recordings

M.I. Martin-Erdozain, I. Barbancho, A. Rosa-Pujazon, A.M. Barbancho, "Correction system for polyphonic piano recordings", XXVIII Simposium Nacional de la Unión Científica Internacional de Radio, Santiago de Compostela, España, 2013n this paper, a support tool for piano rehearsal is presented. The system analyses a given piano polyphonic recording to find the times, pitch and duration of the notes and figures played, taking into account the possibility of playing more than one note simultaneously as well as covering the whole piano frequency range. In order to do so, the system uses an onset detection algorithm to segment the input signal into partitions which are then analysed in the time and frequency domains. Then, the system correlates the data extracted from the partitions with the score of the original piece, identifying the positions and type of the mistakes performed by the user, and providing her/him with the corresponding feedback. The experiments conducted showed that the application is capable of analysing a given recording and indicate the musician the mistakes made.This work has been funded by the Ministerio de Economia y Competitividad of the Spanish Government under Project No. TIN2010-21089-C03-02 and by the Ministerio de Industria, Turismo y Comercio under Project No. TSI-090100-2011-25

A new approach to onset detection: towards an empirical grounding of theoretical and speculative ideologies of musical performance

This article assesses aspects of the current state of a project which aims, with the help of computers and computer software, to segment soundfiles of vocal melodies into their component notes, identifying precisely when the onset of each note occurs, and then tracking the pitch trajectory of each note, especially in melodies employing a variety of non-standard temperaments, in which musical intervals smaller than 100 cents are ubiquitous. From there, we may proceed further, to describe many other “micro-features” of each of the notes, but for now our focus is on the onset times and pitch trajectories

THGEM operation in Ne and Ne/CH4

The operation of Thick Gaseous Electron Multipliers (THGEM) in Ne and Ne/CH4 mixtures, features high multiplication factors at relatively low operation potentials, in both single- and double-THGEM configurations. We present some systematic data measured with UV-photons and soft x-rays, in various Ne mixtures. It includes gain dependence on hole diameter and gas purity, photoelectron extraction efficiency from CsI photocathodes into the gas, long-term gain stability and pulse rise-time. Position resolution of a 100x100 mm^2 X-rays imaging detector is presented. Possible applications are discussed.Comment: Submitted to JINST, 25 pages, 33 figure

Investigation of charge sharing among electrode strips for a CdZnTe detector

We have investigated charge sharing among the anode strips of a CdZnTe (CZT) detector using a 30 micrometer collimated gamma-ray beam. We compared the laboratory measurements with the predictions from our modeling of the charge transport within the detector. The results indicate that charge sharing is a function of the interaction depth and the energy of the incoming photon. Also, depending on depth, a fraction of the electrons might drift to the inter-anode region causing incomplete charge collection. Here, we show that photoelectron range and diffusion of the charge cloud are the principal causes of charge sharing and obtain limits on the size of the electron cloud as a function of position in the detector.Comment: 16 pages 10 figures. Accepted for publication in Nuclear Instruments and Methods -

Spatiotemporal evolution of runaway electrons from synchrotron images in Alcator C-Mod

In the Alcator C-Mod tokamak, relativistic runaway electron (RE) generation can occur during the flattop current phase of low density, diverted plasma discharges. Due to the high toroidal magnetic field (B = 5.4 T), RE synchrotron radiation is measured by a wide-view camera in the visible wavelength range (~400-900 nm). In this paper, a statistical analysis of over one thousand camera images is performed to investigate the plasma conditions under which synchrotron emission is observed in C-Mod. In addition, the spatiotemporal evolution of REs during one particular discharge is explored in detail via a thorough analysis of the distortion-corrected synchrotron images. To accurately predict RE energies, the kinetic solver CODE [Landreman et al 2014 Comput. Phys. Commun. 185 847-855] is used to evolve the electron momentum-space distribution at six locations throughout the plasma: the magnetic axis and flux surfaces q = 1, 4/3, 3/2, 2, and 3. These results, along with the experimentally-measured magnetic topology and camera geometry, are input into the synthetic diagnostic SOFT [Hoppe et al 2018 Nucl. Fusion 58 026032] to simulate synchrotron emission and detection. Interesting spatial structure near the surface q = 2 is found to coincide with the onset of a locked mode and increased MHD activity. Furthermore, the RE density profile evolution is fit by comparing experimental to synthetic images, providing important insight into RE spatiotemporal dynamics