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Publications

Publications by Jaime Cardoso

2015

Fingerprint Liveness Detection in the Presence of Capable Intruders

Authors
Sequeira, AF; Cardoso, JS;

Publication
SENSORS

Abstract
Fingerprint liveness detection methods have been developed as an attempt to overcome the vulnerability of fingerprint biometric systems to spoofing attacks. Traditional approaches have been quite optimistic about the behavior of the intruder assuming the use of a previously known material. This assumption has led to the use of supervised techniques to estimate the performance of the methods, using both live and spoof samples to train the predictive models and evaluate each type of fake samples individually. Additionally, the background was often included in the sample representation, completely distorting the decision process. Therefore, we propose that an automatic segmentation step should be performed to isolate the fingerprint from the background and truly decide on the liveness of the fingerprint and not on the characteristics of the background. Also, we argue that one cannot aim to model the fake samples completely since the material used by the intruder is unknown beforehand. We approach the design by modeling the distribution of the live samples and predicting as fake the samples very unlikely according to that model. Our experiments compare the performance of the supervised approaches with the semi-supervised ones that rely solely on the live samples. The results obtained differ from the ones obtained by the more standard approaches which reinforces our conviction that the results in the literature are misleadingly estimating the true vulnerability of the biometric system.

2017

Mobile-Based Analysis of Malaria-Infected Thin Blood Smears: Automated Species and Life Cycle Stage Determination

Authors
Rosado, L; da Costa, JMC; Elias, D; Cardoso, JS;

Publication
SENSORS

Abstract
Microscopy examination has been the pillar of malaria diagnosis, being the recommended procedure when its quality can be maintained. However, the need for trained personnel and adequate equipment limits its availability and accessibility in malaria-endemic areas. Rapid, accurate, accessible diagnostic tools are increasingly required, as malaria control programs extend parasite-based diagnosis and the prevalence decreases. This paper presents an image processing and analysis methodology using supervised classification to assess the presence of malaria parasites and determine the species and life cycle stage in Giemsa-stained thin blood smears. The main differentiation factor is the usage of microscopic images exclusively acquired with low cost and accessible tools such as smartphones, a dataset of 566 images manually annotated by an experienced parasilogist being used. Eight different species-stage combinations were considered in this work, with an automatic detection performance ranging from 73.9% to 96.2% in terms of sensitivity and from 92.6% to 99.3% in terms of specificity. These promising results attest to the potential of using this approach as a valid alternative to conventional microscopy examination, with comparable detection performances and acceptable computational times.

2016

A review of automatic malaria parasites detection and segmentation in microscopic images

Authors
Rosado, L; Correia da Costa, JM; Elias, D; Cardoso, JS;

Publication
Anti-Infective Agents

Abstract
Background: Malaria is a leading cause of death and disease in many developing countries, where young children and pregnant women are the most affected groups. In 2012, there were an estimated 207 million cases of malaria, which caused approximately 627 000 malaria deaths. Around 80% of malaria cases occur in Africa, where the lack of access to malaria diagnosis is largely due to a shortage of expertise, being the shortage of equipment the secondary factor. This lack of expertise for malaria diagnosis frequently results on the increase of false positives, since prescription of medication is based only on symptoms. Thus, there is an urgent need of new tools that can facilitate the rapid and easy diagnosis of malaria, especially in areas with limited access to quality healthcare services. Methods: Various image processing and analysis approaches already proposed on the literature for the detection and segmentation of malaria parasites in blood smear microscopic images were collected and reviewed. This timely review aims to support the increasing interest in the development of low cost tools that can facilitate the rapid and easy diagnosis of malaria, especially in areas with limited access to quality healthcare services. Results: Malaria parasites detection and segmentation techniques in microscopic images are, in general, still in need of improvement and further testing. Most of the methodologies reviewed in this work were tested with a limited number of images, and more studies with significantly larger datasets for the evaluation of the proposed approaches are needed. Despite promising results reported during the past years, the great majority of the computer-aided methods found on the literature for malaria diagnosis are based on images acquired under well controlled conditions and with proper microscopic equipment. However, one should take into account that 80% of malaria cases occur in Africa, where this type of equipment is scarce or even nonexistent in common healthcare facilities. Conclusion: This work collects and reviews various image processing and analysis approaches already proposed on the literature for the detection and segmentation of malaria parasites in blood smear microscopic images. This timely review aims to support the increasing interest in the development of image processing-based systems to be used in rural areas of developing countries, which might be the next future trend in malaria computer-aided diagnosis. © 2016 Bentham Science Publishers.

2013

Cosmetic outcome after intraoperative radiotherapy or external beam radiotherapy for early breast cancer: An objective assessment of patients from a randomized controlled trial

Authors
Keshtgar, MR; Williams, NR; Corica, T; Bulsara, M; Saunders, C; Flyger, H; Bentzon, N; Cardoso, JS; Michalopoulos, N; Joseph, DJ;

Publication
JOURNAL OF CLINICAL ONCOLOGY

Abstract
59 Background: The international randomised contolled TARGeted Intraoperative radioTherapy (TARGIT) trial has demonstrated non-inferiority between the novel technique of TARGIT (intra-operative radiotherapy with Intrabeam) and conventional whole-breast external beam radiotherapy (EBRT) in women with early breast cancer, in terms of the primary outcome measure of risk of local relapse within the treated breast. With very low recurrence rates, cosmesis becomes an increasingly important outcome of breast conserving treatment with both surgery and radiotherapy. This study was performed to determine if the single high dose of TARGIT leads to impaired cosmesis. Methods: A validated, objective assessment tool for evaluation of cosmetic outcome was used. Frontal digital photographs were taken at baseline (before TARGIT or EBRT) and yearly thereafter for up to five years. The photographs were analysed by BCCT.core software which produces a composite score based on symmetry, colour and scar. Results: 342 patients were assessed, all over 50 years old with a median age at baseline of 64 years (IQR 59 to 68). The scores were dichotomised into Excellent and Good (EG), and Fair and Poor (FP). There were statistically significant increases in the odds of having an outcome of EG for patients in the TARGIT group relative to the EBRT group at year 1 (OR = 2.07, 95% CI 1.12 to 3.85, p = 0.021) and year 2 (OR = 2.11, 95% CI 1.0 to 4.45, p = 0.05). Conclusions: Following an objective assessment of aesthetic outcome in patients from a randomised setting, this study demonstrates that those treated with targeted intraoperative radiotherapy have a superior cosmetic result compared with those patients who received conventional whole-breast external beam radiotherapy.

2016

Preface: DLMIA 2016

Authors
Carneiro, G; Tavares, JMRS; Bradley, A; Papa, JP; Nascimento, JC; Cardoso, JS; Belagiannis, V; Lu, Z;

Publication
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Abstract

2016

Automated detection of malaria parasites on thick blood smears via mobile devices

Authors
Rosado, L; da Costa, JMC; Elias, D; Cardoso, JS;

Publication
20TH CONFERENCE ON MEDICAL IMAGE UNDERSTANDING AND ANALYSIS (MIUA 2016)

Abstract
An estimated 214 million cases of malaria were detected in 2015, which caused approximately 438 000 deaths. Around 90% of those cases occurred in Africa, where the lack of access to malaria diagnosis is largely due to shortage of expertise and equipment. Thus, the importance to develop new tools that facilitate the rapid and easy diagnosis of malaria for areas with limited access to healthcare services cannot be overstated. This paper presents an image processing and analysis methodology using supervised classification to assess the presence of P. falciparum trophozoites and white blood cells in Giemsa stained thick blood smears. The main differential factor is the usage of microscopic images exclusively acquired with low cost and accessible tools such as smartphones, using a dataset of 194 images manually annotated by an experienced parasilogist. Using a SVM classifier and a total of 314 image features extracted for each candidate, the automatic detection of trophozoites detection achieved a sensitivity of 80.5% and a specificity of 93.8%, while the white blood cells achieved 98.2% of sensitivity and 72.1% specificity. (C) 2016 The Authors. Published by Elsevier B.V.

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