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Publications

Publications by Aurélio Campilho

2013

Automatic Lane Segmentation in TLC Images Using the Continuous Wavelet Transform

Authors
Moreira, B; Sousa, A; Mendonca, AM; Campilho, A;

Publication
COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE

Abstract
This paper describes a new methodology for lane detection in Thin-Layer Chromatography images. An approach based on the continuous wavelet transform is used to enhance the relevant lane information contained in the intensity profile obtained from image data projection. Lane detection proceeds in three phases: the first obtains a set of candidate lanes, which are validated or removed in the second phase; in the third phase, lane limits are calculated, and subtle lanes are recovered. The superior performance of the new solution was confirmed by a comparison with three other methodologies previously described in the literature.

2013

Correction of Geometrical Distortions in Bands of Chromatography Images

Authors
Moreira, BM; Sousa, AV; Mendonca, AM; Campilho, A;

Publication
IMAGE ANALYSIS AND RECOGNITION

Abstract
This paper presents a methodology for correcting band distortions in Thin-Layer Chromatography (TLC) images. After the segmentation of image lanes, the intensity profile of each lane column is spatially aligned with a reference profile using a modified version of the Correlation Optimized Warping (COW) algorithm. As the initial partition of the profile into equal length segments proposed by COW can result in the separation of a single band between two segments to be disjointedly aligned, in the proposed method the warping function is only applied to selected profile regions containing groups of adjacent bands. The proposed band correction methodology was assessed using 105 profiles of 105 TLC lanes. A set of features for band characterization was extracted from each lane profile, before and after band distortion correction, and was used as input for three distinct one-class classifiers aiming at band identification. In all cases, the best results of band classification were obtained for the set lanes after band distortion correction.

2013

Automatic localization of the optic disc by combining vascular and intensity information

Authors
Mendonca, AM; Sousa, A; Mendonca, L; Campilho, A;

Publication
COMPUTERIZED MEDICAL IMAGING AND GRAPHICS

Abstract
This paper describes a new methodology for automatic location of the optic disc in retinal images, based on the combination of information taken from the blood vessel network with intensity data. The distribution of vessel orientations around an image point is quantified using the new concept of entropy of vascular directions. The robustness of the method for OD localization is improved by constraining the search for maximal values of entropy to image areas with high intensities. The method was able to obtain a valid location for the optic disc in 1357 out of the 1361 images of the four datasets.

2013

Automatic Estimation of the Arteriolar-to-Venular Ratio in Retinal Images Using a Graph-Based Approach for Artery/Vein Classification

Authors
Dashtbozorg, B; Mendonca, AM; Campilho, A;

Publication
IMAGE ANALYSIS AND RECOGNITION

Abstract
The Arteriolar-to-Venular Ratio (AVR) is a well known index for the diagnosis of diseases such as diabetes, hypertension or cardiovascular pathologies. This paper presents a fully automatic AVR estimation method which uses a graph-based artery/vein classification approach to classify the retinal vessels by a combination of structural information taken from the vasculature graph with intensity features from the original color image. This method was evaluated on the images of the INSPIRE-AVR dataset. The mean error and the correlation coefficient of obtained results with respect to the reference AVR values were identical to the ones obtained by the second observer using a semi-automated system, which demonstrate the potential of the herein proposed solution for clinical application.

2013

Classification Approach for Measurement of Atherosclerosis Using B-Mode Ultrasound Carotid Images

Authors
Carvalho, C; Rocha, R; Campilho, A;

Publication
IMAGE ANALYSIS AND RECOGNITION

Abstract
This paper presents an approach for the detection and delineation of the interfaces at the near and far walls of carotid artery using B-mode ultrasound images. After the delineation the system measures automatically the carotid intima-media thickness (IMT) in order to aid the diagnosis of the atherosclerosis. In this method we start by the measurement, at a pixel level, of local features followed by the selection of the most discriminant ones. The next stage is a classification step which assigns a probability to the pixels to belong to an interface, enabling the detection of the carotid artery interfaces. The final artery boundaries are delineated using a dynamic programming approach. The final measurements of IMT produced by the automatic method proposed in this paper were compared with three manual tracings of experts. It was also compared with an automatic method previously developed. The results show that the two automatic detection methods have similar performance, although with slight improvements in the new method, particularly for the the far wall interface.

2016

Image Analysis and Recognition

Authors
Campilho, A; Karray, F;

Publication
Lecture Notes in Computer Science

Abstract

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