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- Fractional Diffusion (2)
- Image Processing (2)
- Non-negative Tensor Factorisation (2)
- Sound Source Separation (2)
- Beta Divergence (1)
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- Detection (1)
- Drum Sound Separation (1)
- Information Hiding (1)
- Inverse Scattering (1)
- Localization Quality Assessment in Source Separation-Based Upmixing Algorithms (1)
- Meter (1)
- Multiple Scattering (1)
- Music (1)
- Non-negative tensor factorisation (1)
- Print Authentication (1)
- Side-band Systems (1)
- Signal Reconstruction (1)
- Sound source separation (1)
- Stochastic Disfusion (1)
- Synthetic Aperture Radar (1)
- Tenuous Random Media (1)
- Transform Methods (1)
Articles 1 - 10 of 10
Full-Text Articles in Engineering
Diffusion And Fractional Diffusion Based Image Processing, Jonathan Blackledge
Diffusion And Fractional Diffusion Based Image Processing, Jonathan Blackledge
Conference papers
We consider the background to describing strong scattering in terms of diffusive processes based on the diffusion equation. Intermediate strength scattering is then considered in terms of a fractional diffusion equation which is studied using results from fractional calculus. This approach is justified in terms of the generalization of a random walk model with no statistical bias in the phase to a random walk that has a phase bias and is thus, only ‘partially’ or ‘fractionally’ diffusive. A Green’s function solution to the fractional diffusion equation is studied and a result derived that provides a model for an incoherent image …
Inverse Scattering Solutions For Side-Band Signals, Jonathan Blackledge, Timo Hamalainen, Jyrki Joutsensalo
Inverse Scattering Solutions For Side-Band Signals, Jonathan Blackledge, Timo Hamalainen, Jyrki Joutsensalo
Conference papers
When a signal is recorded that has been physically generated by some scattering process (the interaction of electromagnetic waves with an inhomogeneous dielectric, for example), the `standard model' for the signal (i.e. information content convolved with a characteristic Impulse Response Function) is usually based on a single scattering approximation. An additive noise term is introduced into the model to take into account a range of non-deterministic factors including multiple scattering that, along with electronic noise and other background noise sources, is assumed to be relatively weak. Thus, the standard model is based on a `weak field condition' and the inverse …
Localization Quality Assessment In Source Separation-Based Upmixing Algorithms, Dan Barry, Gavin Kearney
Localization Quality Assessment In Source Separation-Based Upmixing Algorithms, Dan Barry, Gavin Kearney
Conference papers
In this paper we explore the source localisation accuracy and perceived spatial distortion of a source separation based upmix algorithm for 2 to 5 channel conversion. Unlike traditional upmixing techniques, source separation based techniques allow individual sources to be separated from the mixture and repositioned independently within the surround sound field. Generally, spectral artefacts and source interference generated during the source separation process are masked when the upmixed sound field is presented in its entirety; however, this can lead to perceived spatial distortion and ambiguous source localisation. Here, we use subjective testing to compare the localisation perceived on a purposely …
Automatic Musical Meter Detection, Mikel Gainza
Automatic Musical Meter Detection, Mikel Gainza
Conference papers
A method that automatically estimates the metrical structure of a piece of music is presented. The approach is based on the generation of a beat similarity matrix, which provided information about the similarity between any two beats of a piece of music. The repetitive structure of most music is exploited by processing the beat similarity matrix in order to identify similar patterns of beats in different parts of a piece. This principles proves to be equally effective for the detection of both duple and triple meters as awll as complex meters. The use of beat positions and dynamic programming techniques …
Structural Segmentation Of Irish Traditional Music Using Chroma At Set Accented Tone Locations, Cillian Kelly, Mikel Gainza, David Dorran, Eugene Coyle
Structural Segmentation Of Irish Traditional Music Using Chroma At Set Accented Tone Locations, Cillian Kelly, Mikel Gainza, David Dorran, Eugene Coyle
Conference papers
An approach is presented which provides a structural segmentation of Irish Traditional Music. Chroma information is extracted at certain locations within the music. The resulting chroma vectors are compared to determine similar structural segments. Chroma is only calculated at "set accented tone" locatins within the music. "Set accented tones" are considered to be impervious to melodic variation and are entirely representative of an Irish Traditional tune. Results show that comparing "set accented tones" represented by chroma significantly increases the structural segmentation accuracy that when "set accented tones" are represented by pitch values.
Using Tensor Factorisation Models To Separate Drums From Polyphonic Music, Derry Fitzgerald, Matt Cranitch, Eugene Coyle
Using Tensor Factorisation Models To Separate Drums From Polyphonic Music, Derry Fitzgerald, Matt Cranitch, Eugene Coyle
Conference papers
This paper describes the use of Non-negative Tensor Factorisation models for the separation of drums from polyphonic audio. Improved separation of the drums is achieved through the incorporation of Gamma Chain priors into the Non-negative Tensor Factorisation framework. In contrast to many previous approaches, the method used in this paper requires little or no pre-training or use of drum templates. The utility of the technique is shown on real-world audio examples.
Musical Sound Source Separation Using Extended Tensor Decompositions, Derry Fitzgerald
Musical Sound Source Separation Using Extended Tensor Decompositions, Derry Fitzgerald
Conference papers
Recently, tensor decompositions have found use in sound source separation. In particular, non-negative tensor decompositions have received a lot of attention due to their ability to decompose audio spectrograms into meaningful ”parts” such as individual notes. Extensions to the basic non-negative tensor factorisation framework allow the incorporation of additional constraints, such as shift-invariance in both frequency and time. This enables the factorisations to capture more complex structures than individual notes, such as individual sources playing different pitches and time-evolving instrument timbres. Further music specific constraints such as harmonicity and source-filter modeling have been shown to improve separation performance for musical …
Imaging Reconstruction For Light Scattering From A Tenuous Random Medium, Jonathan Blackledge
Imaging Reconstruction For Light Scattering From A Tenuous Random Medium, Jonathan Blackledge
Conference papers
We consider the basis for describing strong scattering in terms of diffusive processes based on the diffusion equation. Intermediate strength scattering is then considered in terms of a fractional diffusion equation which is studied using results from fractional calculus. This approach is justified in terms of the generalization of a random walk model with no statistical bias in the phase to a random walk that has a phase bias and is thus, only `partially' or `fractionally' diffusive. A Green's function solution to the fractional diffusion equation is studied and a result derived that provides a model for an incoherent image …
On The Use Of The Beta Divergence For Musical Source Separation, Derry Fitzgerald, Matt Cranitch, Eugene Coyle
On The Use Of The Beta Divergence For Musical Source Separation, Derry Fitzgerald, Matt Cranitch, Eugene Coyle
Conference papers
Non-negative Tensor Factorisation based methods have found use in the context of musical sound source separation. These techniques require the use of a suitable cost function to determine the optimal factorisation, and most work has focused on the use of the generalised Kullback-Liebler divergence, and more recently the Itakura-Saito divergence. These divergences can be regarded as limiting cases of the parameterised Beta divergence. This paper looks at the use of the Beta Divergence in the context of musical source separation with a view to determining an optimal value of Beta for this problem. This is considered for both magnitude and …
Information Hiding By Stochastic Disfusion And Its Application To Printed Document Authentication, Jonathan Blackledge, Eugene Coyle
Information Hiding By Stochastic Disfusion And Its Application To Printed Document Authentication, Jonathan Blackledge, Eugene Coyle
Conference papers
The use of image based information exchange has grown rapidly over the years in terms of both e-to-e image storage and transmission and in terms of maintaining paper documents in electronic form. Further, with the dramatic improvements in the quality of COTS (Commercial-O-The-Shelf) printing and scanning devices, the ability to counterfeit electronic and printed documents has become a widespread problem. Consequently, there has been an increasing demand to develop digital watermarking, information hiding and covert encryption methods which can be applied to both electronic and printed images (and documents) for the purposes of authentication, prevent unauthorized copying and, in the …