Search Results for author: Niko Brümmer

Found 16 papers, 5 papers with code

Toroidal Probabilistic Spherical Discriminant Analysis

2 code implementations27 Oct 2022 Anna Silnova, Niko Brümmer, Albert Swart, Lukáš Burget

It extends PSDA with the ability to model within and between-speaker variabilities in toroidal submanifolds of the hypersphere.

Speaker Recognition

Probabilistic Spherical Discriminant Analysis: An Alternative to PLDA for length-normalized embeddings

3 code implementations28 Mar 2022 Niko Brümmer, Albert Swart, Ladislav Mošner, Anna Silnova, Oldřich Plchot, Themos Stafylakis, Lukáš Burget

In speaker recognition, where speech segments are mapped to embeddings on the unit hypersphere, two scoring backends are commonly used, namely cosine scoring or PLDA.

Speaker Recognition

How to use KL-divergence to construct conjugate priors, with well-defined non-informative limits, for the multivariate Gaussian

no code implementations15 Sep 2021 Niko Brümmer

The Wishart distribution is the standard conjugate prior for the precision of the multivariate Gaussian likelihood, when the mean is known -- while the normal-Wishart can be used when the mean is also unknown.

The Phonexia VoxCeleb Speaker Recognition Challenge 2021 System Description

no code implementations5 Sep 2021 Josef Slavíček, Albert Swart, Michal Klčo, Niko Brümmer

We describe the Phonexia submission for the VoxCeleb Speaker Recognition Challenge 2021 (VoxSRC-21) in the unsupervised speaker verification track.

Clustering Contrastive Learning +2

Out of a hundred trials, how many errors does your speaker verifier make?

1 code implementation1 Apr 2021 Niko Brümmer, Luciana Ferrer, Albert Swart

For perfect calibration, the Bayes error-rate is upper bounded by min(EER, P, 1-P), where EER is the equal-error-rate and P, 1-P are the prior probabilities of the competing hypotheses.

Probabilistic embeddings for speaker diarization

1 code implementation6 Apr 2020 Anna Silnova, Niko Brümmer, Johan Rohdin, Themos Stafylakis, Lukáš Burget

We apply the proposed probabilistic embeddings as input to an agglomerative hierarchical clustering (AHC) algorithm to do diarization in the DIHARD'19 evaluation set.

Clustering speaker-diarization +1

Language-depedent I-Vectors for LRE15

no code implementations29 Sep 2017 Niko Brümmer, Albert Swart

A standard recipe for spoken language recognition is to apply a Gaussian back-end to i-vectors.

Note on the equivalence of hierarchical variational models and auxiliary deep generative models

no code implementations8 Mar 2016 Niko Brümmer

This note compares two recently published machine learning methods for constructing flexible, but tractable families of variational hidden-variable posteriors.

BIG-bench Machine Learning

VB calibration to improve the interface between phone recognizer and i-vector extractor

no code implementations12 Oct 2015 Niko Brümmer

We show here that the classical i-vector extractor recipe is actually a mean-field variational Bayes (VB) recipe.

Constrained speaker linking

no code implementations26 Mar 2014 David A. van Leeuwen, Niko Brümmer

In this paper we study speaker linking (a. k. a.\ partitioning) given constraints of the distribution of speaker identities over speech recordings.

Speaker Recognition

Bayesian calibration for forensic evidence reporting

no code implementations24 Mar 2014 Niko Brümmer, Albert Swart

We introduce a Bayesian solution for the problem in forensic speaker recognition, where there may be very little background material for estimating score calibration parameters.

Speaker Recognition

A comparison of linear and non-linear calibrations for speaker recognition

no code implementations11 Feb 2014 Niko Brümmer, Albert Swart, David van Leeuwen

In recent work on both generative and discriminative score to log-likelihood-ratio calibration, it was shown that linear transforms give good accuracy only for a limited range of operating points.

Speaker Recognition

The EM algorithm and the Laplace Approximation

no code implementations24 Jan 2014 Niko Brümmer

The Laplace approximation calls for the computation of second derivatives at the likelihood maximum.

Generative Modelling for Unsupervised Score Calibration

no code implementations4 Nov 2013 Niko Brümmer, Daniel Garcia-Romero

Score calibration enables automatic speaker recognizers to make cost-effective accept / reject decisions.

Likelihood-ratio calibration using prior-weighted proper scoring rules

no code implementations30 Jul 2013 Niko Brümmer, George Doddington

Prior-weighted logistic regression has become a standard tool for calibration in speaker recognition.

regression Speaker Recognition

The BOSARIS Toolkit: Theory, Algorithms and Code for Surviving the New DCF

1 code implementation10 Apr 2013 Niko Brümmer, Edward de Villiers

This poses the challenges of (i) how to decide what number of trials is enough, and (ii) how to process such large data sets with reasonable memory and CPU requirements.

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