Fernando Perdigão

University of Coimbra

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Co-Authors

Sara Candeias

American Jewish Committee

Carla Lopes

Instituto Politécnico de Leiria

Arlindo Veiga

University of Coimbra

Jorge Proença

University of Coimbra

Jaime Santos

University of Coimbra

Dirce Celorico

Instituto de Telecomunicações

Mário Santos

University of Coimbra

Marco Gomes

Instituto de Telecomunicações

Lorena Petrella

University of Coimbra

Miguel Caixinha

University of Beira Interior

Cooperative Institutions

University of Coimbra

Instituto de Telecomunicações

Institute for Systems Engineering and Computers

University of Aveiro

University of Lisbon

Universidade do Porto

Weatherford College

Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento

Universidade Nova de Lisboa

Universidade de São Paulo

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Investigating New Syllable Prototypes for the Portuguese Language.

ICPhS (2011)

Sara Candeias Fernando Perdigão

Brazilian Portuguese

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Citations (1)

Syllable structure in dysfuntional portuguese children speech

Sara Candeias Fernando Perdigão

Brazilian Portuguese

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Citations (0)

A-scan ultrasonic system for real time automatic cataract detection

Health and Technology (2020)

Lorena Petrella Carlos Pinto Fernando Perdigão Marco Gomes Mário Santos

Gold standard (test)

SIGNAL (programming language)

10.1007/s12553-020-00445-2

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Citations (4)

Feasibility assessment of the Eye Scan Ultrasound System for cataract characterization and optimal phacoemulsification energy estimation: protocol for a pilot, nonblinded and monocentre study

Pilot and Feasibility Studies (2022)

Lorena Petrella Sandrina Nunes Fernando Perdigão Marco Gomes Mário Santos

Abstract Background Cataracts are lens opacifications that are responsible for more than half of blindness cases worldwide, and the only treatment is surgical intervention. Phacoemulsification surgery, the most frequently performed cataract surgery in developed countries, has associated risks, some of which are related to excessive phacoemulsification energy levels and times. The protocol proposed in herein will be used to evaluate the feasibility of a new experimental medical device, the Eye Scan Ultrasound System (ESUS), for the automatic classification of cataract type and severity and quantitative estimation of the optimal phacoemulsification energy. Methods The pilot study protocol will be used to evaluate the feasibility and safety of the ESUS in clinical practice. The study will be conducted in subjects with age-related cataracts and on healthy subjects as controls. The procedures include data acquisition with the experimental ESUS, classification based on the Lens Opacity Classification System III (LOCS III, comparator) using a slit lamp, contrast sensitivity test, optical coherence tomography, specular microscopy and surgical parameters. ESUS works in A-scan pulse-echo mode, with a central frequency of 20 MHz. From the collected signals, acoustic parameters will be extracted and used for automatic cataract characterization and optimal phacoemulsification energy estimation. The study includes two phases. The data collected in the first phase (40 patients, 2 eyes per patient) will be used to train the ESUS algorithms, while the data collected in the second phase (10 patients, 2 eyes per patient) will be used to assess the classification performance. System safety will be monitored during the study. Discussion The present pilot study protocol will evaluate the feasibility and safety of the ESUS for use in clinical practice, and the results will support a larger clinical study for the efficacy assessment of the ESUS as a diagnostic tool. Ultimately, the ESUS is expected to represent a valuable tool for surgical planning by reducing complications associated with excessive levels of phacoemulsification energy and surgical times, which will have a positive impact on healthcare systems and society. The study is not yet recruiting. Trial registration ClinicalTrials.gov identifier NCT04461912 , registered on July 8, 2020.

Ultrasound energy

10.1186/s40814-022-01173-2

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Automatic Annotation of Disfluent Speech in Children’s Reading Tasks

Lecture notes in computer science (2016)

Jorge Proença Dirce Celorico Carla Lopes Sara Candeias Fernando Perdigão

Pronunciation

Text segmentation

10.1007/978-3-319-49169-1_17

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Citations (3)

Properties of Auditory Model Representations.

Conference of the International Speech Communication Association (1997)

Fernando Perdigão Luís Sá

We address the problem of robustness of auditory models as front ends for speech recognition. Auditory models have been referred as superior front ends when speech is corrupted by noise or linear filtering, but there is not yet a deep understanding of its functioning. We analyze some commonly used auditory models and show that they present some interesting properties which are useful for robust speech recognition. In our view, the short-time adaptation provided by hair cell models is a key factor for this robustness. A disadvantage of auditory models is that the distributions of the obtained features are not well represented by gaussian pdfs. We discuss the problem of parameter transformation in order to use a standard recognizer based on CDHMMs with gaussian pdfs and present some digit recognition experiments.

Robustness

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A multiprocessing system for the TMS32020

Microprocessing and Microprogramming (1988)

Luís Vieira de Sá Fernando Perdigão

10.1016/0165-6074(88)90359-6

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Query by example search with segmented dynamic time warping for non-exact spoken queries

Jorge Proenga Arlindo Veiga Fernando Perdigão

This paper presents an approach to the Query-by-Example task of finding spoken queries on speech databases when the intended match may be non-exact or slightly complex. The built system is low-resource as it tries to solve the problem where the language of queries and searched audio is unspecified. Our method is based on a modified Dynamic Time Warping (DTW) algorithm using posterior-grams and extracting intricate paths to account for special cases of query match such as word re-ordering, lexical variations and filler content. This system was evaluated on the MediaEval 2014 task of Query by Example Search on Speech (QUESST) where the spoken data is from different languages, unknown to the participant. We combined the results of five DTW modifications computed on the output of three phoneme recognizers of different languages. The combination of all systems provided the best performance overall and improved detection of complex case queries.

Dynamic Time Warping

Spoken Language

10.1109/eusipco.2015.7362666

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Citations (14)

Children's reading aloud performance: a database and automatic detection of disfluencies

Interspeech 2022 (2015)

Jorge Proença Dirce Celorico Sara Candeias Carla Lopes Fernando Perdigão

Reading aloud

10.21437/interspeech.2015-382

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Citations (8)

Multi-conference over HF packet radio channels

António Navarro Rui Rodrigues J. Angeja João Tavares L. Carvalho

The main objective of the research prototype is to demonstrate a narrow band multi-conference system over the Internet where one route is a high frequency (HF) wireless link.

High frequency

Packet radio

Radio spectrum

10.1109/icme.2004.1394188

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