André Marcal

Prof. André Marcal


Research Focus & Metrics

Academic Career Length

30Years (1997-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 July 2013
Verified
Conference Paper
Closed access
TMTeresa Mendonca
Teresa Mendonca
PFPedro M. Ferreira
Pedro M. Ferreira
JMJorge S. Marques
Jorge S. Marques
André MarcalAndré Marcal
André Marcal
JRJorge Rozeira
Jorge Rozeira
The increasing incidence of melanoma has recently promoted the development of computer-aided diagnosis systems for the classification of dermoscopic images. Unfortunately, the performance of such systems cannot be compared since they are evaluated in different sets of images by their authors and there are no public databases available to perform a fair evaluation of multiple systems. In this paper, a dermoscopic image database, called PH 2 , is presented. The PH 2 database includes the manual segmentation, the clinical diagnosis, and the identification of several dermoscopic structures, performed by expert dermatologists, in a set of 200 dermoscopic images. The PH 2 database will be made freely available for research and benchmarking purposes.

20 February 2009 in IEEE Journal of Selected Topics in Signal Processing
Verified
Journal Article
Closed access
MSMargarida Silveira
Margarida Silveira
JNJacinto C. Nascimento
Jacinto C. Nascimento
JMJorge S. Marques
Jorge S. Marques
André MarcalAndré Marcal
André Marcal
TMTeresa Mendonca
Teresa Mendonca
JRJorge Rozeira
Jorge Rozeira
In this paper, we propose and evaluate six methods for the segmentation of skin lesions in dermoscopic images. This set includes some state of the art techniques which have been successfully used in many medical imaging problems (gradient vector flow (GVF) and the level set method of Chan et al.[(C-LS)]. It also includes a set of methods developed by the authors which were tailored to this particular application (adaptive thresholding (AT), adaptive snake (AS), EM level set (EM-LS), and fuzzy-based split-and-merge algorithm (FBSM)]. The segmentation methods were applied to 100 dermoscopic images and evaluated with four different metrics, using the segmentation result obtained by an experienced dermatologist as the ground truth. The best results were obtained by the AS and EM-LS methods, which are semi-supervised methods. The best fully automatic method was FBSM, with results only slightly worse than AS and EM-LS.

2 March 2012 in International Journal of Multimedia Information Retrieval
Verified
Journal Article
Open access
PDF file
ARAna Rebelo
Ana Rebelo
IFIchiro Fujinaga
Ichiro Fujinaga
FPFilipe Paszkiewicz
Filipe Paszkiewicz
André MarcalAndré Marcal
André Marcal
CGCarlos Guedes
Carlos Guedes
JCJaime Cardoso
Jaime Cardoso
For centuries, music has been shared and remembered by two traditions: aural transmission and in the form of written documents normally called musical scores. Many of these scores exist in the form of unpublished manuscripts and hence they are in danger of being lost through the normal ravages of time. To preserve the music some form of typesetting or, ideally, a computer system that can automatically decode the symbolic images and create new scores is required. Programs analogous to optical character recognition systems called optical music recognition (OMR) systems have been under intensive development for many years. However, the results to date are far from ideal. Each of the proposed methods emphasizes different properties and therefore makes it difficult to effectively evaluate its competitive advantages. This article provides an overview of the literature concerning the automatic analysis of images of printed and handwritten musical scores. For self-containment and for the benefit of the reader, an introduction to OMR processing systems precedes the literature overview. The following study presents a reference scheme for any researcher wanting to compare new OMR algorithms against well-known ones.


1 January 2013
Verified
Book Chapter
Closed access
PDF file
PSPedro F. B. Silva
Pedro F. B. Silva
André MarcalAndré Marcal
André Marcal
RARubim M. Almeida
Rubim M. Almeida

20 June 2010 in International Journal of Remote Sensing
Verified
Journal Article
Closed access
Mario CunhaMario Cunha
Mario Cunha
André MarcalAndré Marcal
André Marcal
LSLisa Silva
Lisa Silva
A forecast model for estimating the annual variation in regional wine yield based on remote sensing was developed for the main wine regions of Portugal. Normalized Difference Vegetation Index (NDVI) time-series obtained by the VEGETATION sensor, on board the most recent Satellite Pour l'Observation de la Terre (SPOT) satellite, over the period 1998–2008 were used for four test sites located in the main wine regions of Portugal: Douro (two sites), Vinhos Verdes and Alentejo. The CORINE (Coordination of Information on the Environment) Land Cover maps from 2000 were initially used to select the suitable regional test sites. The NDVI values of the second decade of April of the previous season to harvest were significantly correlated to the wine yield for all studied regions. The relation between the NDVI and grapevine induction and differentiation of the inflorescence primordial or bud fruitfulness during the previous season is discussed. This NDVI measurement can be made about 17 months before harvest and allows us to obtain very early forecasts of potential regional wine yield. Appropriate statistical tests indicated that the wine yield forecast model explains 77–88% of the inter-annual variability in wine yield. The comparison of official wine yield and the adjusted prediction models, based on 36 annual data records for all regions, shows an average spread deviation between 2.9% and 7.1% for the different regions. The dataset provided by the VEGETATION sensor proved to be a valuable tool for vineyard monitoring, mainly for inter-annual comparisons on a regional scale due to their high data acquisition rates and wide availability. The accuracy, very early indication and low-cost of the developed forecast model justify its use by the winery and viticulture industry.