David Menotti

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Histogram equalization (HE) has proved to be a simple and effective image contrast enhancement technique. However, it tends to change the mean brightness of the image to the middle level of the gray-level range, which is not desirable in the case of images from consumer electronics products. In the latter case, preserving the input brightness of the image(More)
Spoofing detection is a challenging task in biometric systems, when differentiating illegitimate users from genuine ones. Although iris scans are far more inclusive than fingerprints, and also more precise for person authentication, iris recognition systems are vulnerable to spoofing via textured cosmetic contact lenses. Iris spoofing detection is also(More)
The upper-weighted sets of a signal are the sets of points with weight above a given threshold. The components of the upperweighted sets, thanks to the inclusion relation, can be organized in a tree structure, which is called the component tree. In this work, we present a linear time and space algorithm to compute the component tree of one-dimensional(More)
Author name ambiguity is a hard problem that occurs when several authors publish articles with the same name or when a same author publishes their articles under different names. Traditionally, automatic disambiguation methods process the author names of all citation records in a repository. Aiming efficiency, incremental methods disambiguate author names(More)
An important tool for the heart disease diagnosis is the analysis of electrocardiogram (ECG) signals, since the noninvasive nature and simplicity of the ECG exam. According to the application, ECG data analysis consists of steps such as preprocessing, segmentation, feature extraction and classification aiming to detect cardiac arrhythmias (i.e., cardiac(More)
An electrocardiogram (ECG) measures the electric activity of the heart and has been widely used for detecting heart diseases due to its simplicity and non-invasive nature. By analyzing the electrical signal of each heartbeat, i.e., the combination of action impulse waveforms produced by different specialized cardiac tissues found in the heart, it is(More)
Nowadays devices are able to capture and process images from complex surveillance monitoring systems or from simple mobile phones. In certain applications, the time necessary to process the image is not as important as the quality of the processed images (e.g., medical imaging), but in other cases the quality can be sacrificed in favour of time. This thesis(More)
Many of the difficulties in managing soybean tillage are related to the identification of insect/pests harmful to the plant, since tillage can be attacked by a wide range of such agents. By identifying the most common agents that cause damages to the leaflets, we can obtain more knowledge about appropriate strategies of control. The proposed work presents(More)