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Publications

Publications by Ana Maria Mendonça

2001

Special issue - Selected papers from the 11th Portuguese Conference on Pattern Recognition - RECPAD2000 - Preface

Authors
Campilho, AC; Mendonca, AM;

Publication
PATTERN RECOGNITION LETTERS

Abstract

2008

Tracking of Arabidopsis thaliana root cells in time-lapse microscopy

Authors
Marcuzzo, M; Quelhas, P; Mendonca, AM; Campilho, A;

Publication
19TH INTERNATIONAL CONFERENCE ON PATTERN RECOGNITION, VOLS 1-6

Abstract
In vivo observation of cells in the Arabidopsis thaliana root, by time-lapse confocal microscopy, is central to biology research. The research herein described is based on large amount of image data, which must be analyzed to determine the location and state of individual cells. Automating the process of cell tracking is an important step to create tools which will facilitate the analysis of cells' evolution through time. Here we introduce a confocal tracking system designed in two stages. At the image acquisition stage, we track the area under analysis based on point-to-point correspondences and motion estimation. After image acquisition, we compute cell-to-cell correspondences through time. The final result is a temporal structured information about each cell.

1994

A NEW SIMILARITY CRITERION FOR RETINAL IMAGE REGISTRATION

Authors
MENDONCA, AM; CAMPILHO, A; NUNES, JMR;

Publication
ICIP-94 - PROCEEDINGS, VOL III

Abstract

2011

Automatic segmentation of chromatographic images for region of interest delineation

Authors
Mendonca, AM; Sousa, AV; Sa Miranda, MC; Campilho, AC;

Publication
MEDICAL IMAGING 2011: IMAGE PROCESSING

Abstract
This paper describes a segmentation method for automating the region of interest (ROI) delineation in chromatographic images, thus allowing the definition of the image area that contains the fundamental information for further processing while excluding the frame of the chromatographic plate that does not contain relevant data for disease identification. This is the first component of a screening tool for Fabry disease, which will be based on the automatic analysis of the chromatographic patterns extracted from the image ROI. Image segmentation is performed in two phases, where each individual pixel is finally considered as frame or ROI. In the first phase, an unsupervised learning method is used for classifying image pixels into three classes: frame, ROI or unknown. In the second phase, distance features are used for deciding which class the unknown pixels belong to. The segmentation result is post-processed using a sequence of morphological operators in order to obtain the final ROI rectangular area. The proposed methodology was successfully evaluated in a dataset of 41 chromatographic images.

2004

Automatic delimitation of lung fields on chest radiographs

Authors
Mendonca, AM; da Silva, JA; Campilho, A;

Publication
2004 2ND IEEE INTERNATIONAL SYMPOSIUM ON BIOMEDICAL IMAGING: MACRO TO NANO, VOLS 1 and 2

Abstract
The purpose of the research herein presented is the automatic delimitation of lung fields in posterior-anterior digital chest radiographs. In a computer-aided diagnosis system the precise location of the lungs is important as it allows the reduction of the re-ion under analysis, decreasing the computation time and facilitating data compression. Furthermore, it allows the delimitation of the search area, easing the selective tuning of the abnormalities detection algorithms. The results produced by the automatic method were validated by comparison with manual contours traced by experienced radiologists. Two programs with friendly interfaces were developed for this purpose.

2012

Automatic Localization of the Optic Disc in Retinal Images Based on the Entropy of Vascular Directions

Authors
Mendonca, AM; Cardoso, F; Sousa, AV; Campilho, A;

Publication
IMAGE ANALYSIS AND RECOGNITION, PT II

Abstract
This paper proposes an automatic method for estimating the location of the optic disc in color images of the retina. The proposed methodology is founded in a new concept, the entropy of vascular directions, which proved to be a reliable measure for assessing the convergence of vessels around an image point. To improve the robustness of the method, the search for the maximum value of entropy is restricted to image areas with high intensity. This new method was evaluated in two publicly available databases, containing both normal and pathological images, and was able to obtain a valid location for the optic disc in 115 out of the 121 images of the two datasets.

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