5 research outputs found
CONTRIBUTIONS TO EFFICIENT AUTOMATIC TRANSCRIPTION OF VIDEO LECTURES
Tesis por compendio[ES] Durante los últimos años, los repositorios multimedia en línea se han convertido
en fuentes clave de conocimiento gracias al auge de Internet, especialmente en
el área de la educación. Instituciones educativas de todo el mundo han dedicado
muchos recursos en la búsqueda de nuevos métodos de enseñanza, tanto para
mejorar la asimilación de nuevos conocimientos, como para poder llegar a una
audiencia más amplia. Como resultado, hoy en día disponemos de diferentes
repositorios con clases grabadas que siven como herramientas complementarias en
la enseñanza, o incluso pueden asentar una nueva base en la enseñanza a
distancia. Sin embargo, deben cumplir con una serie de requisitos para que la
experiencia sea totalmente satisfactoria y es aquí donde la transcripción de los
materiales juega un papel fundamental. La transcripción posibilita una búsqueda
precisa de los materiales en los que el alumno está interesado, se abre la
puerta a la traducción automática, a funciones de recomendación, a la
generación de resumenes de las charlas y además, el poder hacer
llegar el contenido a personas con discapacidades auditivas. No obstante, la
generación de estas transcripciones puede resultar muy costosa.
Con todo esto en mente, la presente tesis tiene como objetivo proporcionar
nuevas herramientas y técnicas que faciliten la transcripción de estos
repositorios. En particular, abordamos el desarrollo de un conjunto de herramientas
de reconocimiento de automático del habla, con énfasis en las técnicas de aprendizaje
profundo que contribuyen a proporcionar transcripciones precisas en casos de
estudio reales. Además, se presentan diferentes participaciones en competiciones
internacionales donde se demuestra la competitividad del software comparada con
otras soluciones. Por otra parte, en aras de mejorar los sistemas de
reconocimiento, se propone una nueva técnica de adaptación de estos sistemas al
interlocutor basada en el uso Medidas de Confianza. Esto además motivó el
desarrollo de técnicas para la mejora en la estimación de este tipo de medidas
por medio de Redes Neuronales Recurrentes.
Todas las contribuciones presentadas se han probado en diferentes repositorios
educativos. De hecho, el toolkit transLectures-UPV es parte de un conjunto de
herramientas que sirve para generar transcripciones de clases en diferentes
universidades e instituciones españolas y europeas.[CA] Durant els últims anys, els repositoris multimèdia en línia s'han convertit
en fonts clau de coneixement gràcies a l'expansió d'Internet, especialment en
l'àrea de l'educació. Institucions educatives de tot el món han dedicat
molts recursos en la recerca de nous mètodes d'ensenyament, tant per
millorar l'assimilació de nous coneixements, com per poder arribar a una
audiència més àmplia. Com a resultat, avui dia disposem de diferents
repositoris amb classes gravades que serveixen com a eines complementàries en
l'ensenyament, o fins i tot poden assentar una nova base a l'ensenyament a
distància. No obstant això, han de complir amb una sèrie de requisits perquè la
experiència siga totalment satisfactòria i és ací on la transcripció dels
materials juga un paper fonamental. La transcripció possibilita una recerca
precisa dels materials en els quals l'alumne està interessat, s'obri la
porta a la traducció automàtica, a funcions de recomanació, a la
generació de resums de les xerrades i el poder fer
arribar el contingut a persones amb discapacitats auditives. No obstant, la
generació d'aquestes transcripcions pot resultar molt costosa.
Amb això en ment, la present tesi té com a objectiu proporcionar noves
eines i tècniques que faciliten la transcripció d'aquests repositoris. En
particular, abordem el desenvolupament d'un conjunt d'eines de reconeixement
automàtic de la parla, amb èmfasi en les tècniques d'aprenentatge profund que
contribueixen a proporcionar transcripcions precises en casos d'estudi reals. A
més, es presenten diferents participacions en competicions internacionals on es
demostra la competitivitat del programari comparada amb altres solucions.
D'altra banda, per tal de millorar els sistemes de reconeixement, es proposa una
nova tècnica d'adaptació d'aquests sistemes a l'interlocutor basada en l'ús de
Mesures de Confiança. A més, això va motivar el desenvolupament de tècniques per
a la millora en l'estimació d'aquest tipus de mesures per mitjà de Xarxes
Neuronals Recurrents.
Totes les contribucions presentades s'han provat en diferents repositoris
educatius. De fet, el toolkit transLectures-UPV és part d'un conjunt d'eines
que serveix per generar transcripcions de classes en diferents universitats i
institucions espanyoles i europees.[EN] During the last years, on-line multimedia repositories have become key
knowledge assets thanks to the rise of Internet and especially in the area of
education. Educational institutions around the world have devoted big efforts
to explore different teaching methods, to improve the transmission of knowledge
and to reach a wider audience. As a result, online video lecture repositories
are now available and serve as complementary tools that can boost the learning
experience to better assimilate new concepts. In order to guarantee the success
of these repositories the transcription of each lecture plays a very important
role because it constitutes the first step towards the availability of many other
features. This transcription allows the searchability of learning materials,
enables the translation into another languages, provides recommendation
functions, gives the possibility to provide content summaries, guarantees
the access to people with hearing disabilities, etc. However, the
transcription of these videos is expensive in terms of time and human cost.
To this purpose, this thesis aims at providing new tools and techniques that
ease the transcription of these repositories. In particular, we address the
development of a complete Automatic Speech Recognition Toolkit with an special
focus on the Deep Learning techniques that contribute to provide accurate
transcriptions in real-world scenarios. This toolkit is tested against many
other in different international competitions showing comparable transcription
quality. Moreover, a new technique to improve the recognition accuracy has been
proposed which makes use of Confidence Measures, and constitutes the spark that
motivated the proposal of new Confidence Measures techniques that helped to
further improve the transcription quality. To this end, a new speaker-adapted
confidence measure approach was proposed for models based on Recurrent Neural
Networks.
The contributions proposed herein have been tested in real-life scenarios in
different educational repositories. In fact, the transLectures-UPV toolkit is
part of a set of tools for providing video lecture transcriptions in many
different Spanish and European universities and institutions.Agua Teba, MÁD. (2019). CONTRIBUTIONS TO EFFICIENT AUTOMATIC TRANSCRIPTION OF VIDEO LECTURES [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/130198TESISCompendi
Speech segmentation and speaker diarisation for transcription and translation
This dissertation outlines work related to Speech Segmentation – segmenting an audio
recording into regions of speech and non-speech, and Speaker Diarization – further
segmenting those regions into those pertaining to homogeneous speakers.
Knowing not only what was said but also who said it and when, has many useful
applications. As well as providing a richer level of transcription for speech, we will
show how such knowledge can improve Automatic Speech Recognition (ASR) system
performance and can also benefit downstream Natural Language Processing (NLP)
tasks such as machine translation and punctuation restoration.
While segmentation and diarization may appear to be relatively simple tasks to
describe, in practise we find that they are very challenging and are, in general, ill-defined
problems. Therefore, we first provide a formalisation of each of the problems
as the sub-division of speech within acoustic space and time. Here, we see that the
task can become very difficult when we want to partition this domain into our target
classes of speakers, whilst avoiding other classes that reside in the same space, such as
phonemes. We present a theoretical framework for describing and discussing the tasks
as well as introducing existing state-of-the-art methods and research.
Current Speaker Diarization systems are notoriously sensitive to hyper-parameters
and lack robustness across datasets. Therefore, we present a method which uses a series
of oracle experiments to expose the limitations of current systems and to which
system components these limitations can be attributed. We also demonstrate how Diarization
Error Rate (DER), the dominant error metric in the literature, is not a comprehensive
or reliable indicator of overall performance or of error propagation to subsequent
downstream tasks. These results inform our subsequent research.
We find that, as a precursor to Speaker Diarization, the task of Speech Segmentation
is a crucial first step in the system chain. Current methods typically do not account
for the inherent structure of spoken discourse. As such, we explored a novel method
which exploits an utterance-duration prior in order to better model the segment distribution
of speech. We show how this method improves not only segmentation, but also
the performance of subsequent speech recognition, machine translation and speaker
diarization systems.
Typical ASR transcriptions do not include punctuation and the task of enriching
transcriptions with this information is known as ‘punctuation restoration’. The benefit
is not only improved readability but also better compatibility with NLP systems
that expect sentence-like units such as in conventional machine translation. We show
how segmentation and diarization are related tasks that are able to contribute acoustic
information that complements existing linguistically-based punctuation approaches.
There is a growing demand for speech technology applications in the broadcast media
domain. This domain presents many new challenges including diverse noise and
recording conditions. We show that the capacity of existing GMM-HMM based speech
segmentation systems is limited for such scenarios and present a Deep Neural Network
(DNN) based method which offers a more robust speech segmentation method resulting
in improved speech recognition performance for a television broadcast dataset.
Ultimately, we are able to show that the speech segmentation is an inherently ill-defined
problem for which the solution is highly dependent on the downstream task
that it is intended for
Proceedings of the 17th Annual Conference of the European Association for Machine Translation
Proceedings of the 17th Annual Conference of the European Association for Machine Translation (EAMT
A Text Rewriting Decoder with Application to Machine Translation
Ph.DDOCTOR OF PHILOSOPH