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Publications

Publications by CTM

2014

Morphometric Analysis of Sciatic Nerve Images: A Directional Gradient Approach

Authors
Rodrigues, IV; Ferreira, PM; Malheiro, AR; Brites, P; Pereira, EM; Oliveira, HP;

Publication
2014 IEEE INTERNATIONAL CONFERENCE ON BIOINFORMATICS AND BIOMEDICINE (BIBM)

Abstract
The extraction of morphometric features from images of biological structures is a crucial task for the study of several diseases. Particularly, concerning neuropathies, the state of the myelination process is vital for neuronal integrity and may be an indicator of the disease type and state. Few approaches exist to automatically analyse nerve morphometry and assist researchers in this time consuming task. The aim of this work is to develop an algorithm to detect axons and myelin contours in myelinated fibres of sciatic nerve images, thus allowing the automated assessment and quantification of myelination through the measurement of the g-ratio. The application of a directional gradient together with an active contour algorithm was able to effectively and accurately determine the degree of myelination in an imagiological dataset of sciatic nerves. It was obtained an average error of 1.80%, in comparison with the manual annotation performed by the specialist in all dataset.

2014

Tessellation-based Coarse Registration Method for 3D Reconstruction of the Female Torso

Authors
Costa, P; Monteiro, JP; Zolfagharnasab, H; Oliveira, HP;

Publication
2014 IEEE INTERNATIONAL CONFERENCE ON BIOINFORMATICS AND BIOMEDICINE (BIBM)

Abstract
The medical procedures related with the Breast Cancer Conservative Treatment (BCCT) have evolved towards the usage of affordable and practical tools, along with the recent inclusion of volumetric information of the breast. A richer three-dimensional (3D) model of the female torso allows, for instance, improvement of the evaluation the aesthetic outcome of BCCT and the surgery planning. The standard 3D reconstruction methods often fail to model objects of interest using highly misaligned views. In this work, a Tessellation-based coarse registration method is proposed, based on robust keypoints extraction from RGB-D data using the Delaunay Triangulation (DT) principle. With this method, it is possible to reconstruct female torso data with detail using only 3 views, in feasible time. Structures such as the nipples and the breast contour were correctly reconstructed and a highly correlated with reference models.

2014

The kyte latissimus dorsi flap in breast reconstruction: A technique modification attempt to reduce axillary bulging

Authors
Pinto, D; Gouveia, P; Magalhaes, AT; Bastos Martins, JB; Moura, A; Oliveira, HP; Cardoso, MJ; Mavioso, C; Correia Anacieto, JC;

Publication
EUROPEAN JOURNAL OF CANCER

Abstract

2014

MobBIO: A Multimodal Database Captured with a Portable Handheld Device

Authors
Sequeira, AF; Monteiro, JC; Rebelo, A; Oliveira, HP;

Publication
PROCEEDINGS OF THE 2014 9TH INTERNATIONAL CONFERENCE ON COMPUTER VISION, THEORY AND APPLICATIONS (VISAPP 2014), VOL 3

Abstract
Biometrics represents a return to a natural way of identification: testing someone by what (s) he is, instead of relying on something (s) he owns or knows seems likely to be the way forward. Biometric systems that include multiple sources of information are known as multimodal. Such systems are generally regarded as an alternative to fight a variety of problems all unimodal systems stumble upon. One of the main challenges found in the development of biometric recognition systems is the shortage of publicly available databases acquired under real unconstrained working conditions. Motivated by such need the MobBIO database was created using an Asus EeePad Transformer tablet, with mobile biometric systems in mind. The proposed database is composed by three modalities: iris, face and voice.

2014

Experimental Setup for Electromagnetically Induced Transparency Observation in Hollow-Core Fibers

Authors
Tiburcio, BD; Fernandes, GM; Monteiro, JM; Rodrigues, S; Carvalho, MI; Facao, M; Ferreira, M; Pinto, AN;

Publication
SECOND INTERNATIONAL CONFERENCE ON APPLICATIONS OF OPTICS AND PHOTONICS

Abstract
We developed a system to investigate resonant nonlinear optical interactions in acetylene molecules, confined in a hollow-core photonic crystal fiber (HC-PCF), using light injection through a low-loss splice from one end of the fiber, allowing us to work at low power. Electromagnetically induced transparency (EIT) was observed in the 1500 nm telecommunications window.

2014

Dynamics of blueshifted floating pulses in gas-filled hollow-core photonic crystal fibers

Authors
Facao, M; Carvalho, MI;

Publication
APPLIED PHYSICS B-LASERS AND OPTICS

Abstract
Frequency blueshifting was recently observed in light pulses propagating on gas-filled hollow-core photonic crystal fibers where a plasma has been produced due to photoionization of the gas. One of the propagation models that is adequate to describe the actual experimental observations is here investigated. It is a nonlinear Schrodinger equation with an extra term, to which we applied a self-similar change of variables and found its accelerating solitons. As in other NLS-related models possessing accelerating solitons, there exist asymmetrical pulses that decay as they propagate in some parameter region that was here well defined.

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