Hélder P. Oliveira

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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(More)
Breast cancer is one of the most mediated malignant diseases, because of its high incidence and prevalence, but principally due to its physical and psychological invasiveness. The study of this disease using computer science tools resorts often to the image segmentation operation. Image segmentation, although having been extensively studied, is still an(More)
Breast Cancer Conservative Treatment (BCCT) is considered nowadays to be the most widespread form of locor-regional breast cancer treatment. However, aesthetic results are heterogeneous and difficult to evaluate in a standardized way. The limited reproducibility of subjective aesthetic evaluation in BCCT motivated the research towards objective methods. A(More)
Biometric systems based on iris are vulnerable to several attacks, particularly direct attacks consisting on the presentation of a fake iris to the sensor. The development of iris liveness detection techniques is crucial for the deployment of iris biometric applications in daily life specially in the mobile biometric field. The 1 Mobile Iris Liveness(More)
This paper presents a nonlinear model based predictive controller (NMPC) for trajectory tracking of a mobile robot. Methods of numerical optimization to perform real time nonlinear minimization of the cost function are used. The cost function penalizes the robot position error, the robot orientation angle error and the control effort. Experimental results(More)
"Taking less treating better" has been one of the major improvements of breast cancer surgery in the last four decades. The application of this principle translates into equivalent survival of breast cancer conserving treatment (BCT) when compared to mastectomy, with a better cosmetic outcome. While it is relatively easy to evaluate the oncological results(More)
BACKGROUND AND OBJECTIVE Cosmetic outcome of breast cancer conservative treatment (BCCT) remains without a standard evaluation method. Subjective methods, in spite of their low reproducibility, continue to be the most frequently used. Objective methods, although more reproducible, seem unable to translate all the subtleties involved in cosmetic outcome. The(More)
Breast Cancer Conservative Treatment (BCCT) is now the preferred technique for breast cancer treatment. The limited reproducibility of standard aesthetic evaluation methods led to the development of objective methods, such as Breast Cancer Conservative Treatment.cosmetic results (BCCT.core) software tool. Although the satisfying results, there are still(More)
A 3D low-cost solution for the aesthetic evaluation of breast cancer conservative treatment Hélder P. Oliveira, Jaime S. Cardoso, André T. Magalhães & Maria J. Cardoso a INESC TEC and Faculdade de Engenharia, Universidade do Porto, Porto, Portugal b Faculdade de Medicina, Universidade do Porto, Porto, Portugal c Breast Unit, Champalimaud Cancer Center,(More)
The rising challenges in the field of iris recognition, concerning the development of accurate recognition algorithms using images acquired under an unconstrained set of conditions, is leading to the a renewed interest in the area. Although several works already report excellent recognition rates, these values are obtained by acquiring images in very(More)