11 research outputs found
EDGE DETECTION PARAMETER OPTIMIZATION BASED ON THE GENETIC ALGORITHM FOR RAIL TRACK DETECTION
One of the most important parameters in an edge detection process is setting up the proper threshold value. However, that parameter can be different for almost each image, especially for infrared (IR) images. Traditional edge detectors cannot set it adaptively, so they are not very robust. This paper presents optimization of the edge detection parameter, i.e. threshold values for the Canny edge detector, based on the genetic algorithm for rail track detection with respect to minimal value of detection error. First, determination of the optimal high threshold value is performed, and the low threshold value is calculated based on the well-known method. However, detection results were not satisfactory so that, further on, the determination of optimal low and high threshold values is done. Efficiency of the developed method is tested on set of IR images, captured under night-time conditions. The results showed that quality detection is better and the detection error is smaller in the case of determination of both threshold values of the Canny edge detector
State of the Art of Radar Images Recognition of Surface Ships by Means of Space Monitoring
Поступила: 01.02.2024. Принята в печать: 01.03.2024.Received: 01.02.2024. Accepted: 01.03.2024.Проблема синтеза и анализа алгоритмов обработки радиолокационных изображений пространственно-распределенных целей, полученных средствами космического мониторинга, была и остается одной из наиболее значимых как с теоретических, так и практических позиций для обеспечения безопасности мореплавания, контроля за незаконной добычей рыбы, мониторинга и управления кризисными ситуациями, такими как естественные бедствия, миграционные потоки и другие. Одним из наиболее распространенных приложений названной проблемы является распознавание надводных кораблей, которому и посвящен данный обзор, выполненный по иностранным источникам. В связи с этим предлагаемый обзор, содержащий достаточно подробный анализ современных методов решения названной задачи, предложенных широким кругом авторов в последние десятилетия, будет полезен создателям и исследователям средств космического наблюдения за состоянием морской поверхности.The issue of synthesizing and analyzing algorithms of processing radar images of spatially distributed targets, obtained through space monitoring tools, remains one of the most significant both theoretically and practically. This is particularly crucial for ensuring maritime safety, monitoring illegal fishing activities, and managing crisis situations such as natural disasters and migration flows. One of the most common applications of this problem is the recognition of surface ships, to which this review is devoted. The review is performed using foreign materials. Thus, the proposed review, which includes a detailed analysis of contemporary methods addressing the mentioned challenges, proposed by a wide range of authors over the past decades, will be valuable for developers and researchers in the field of space observation of marine surface conditions
Fusion of Imaging and Inertial Sensors for Navigation
The motivation of this research is to address the limitations of satellite-based navigation by fusing imaging and inertial systems. The research begins by rigorously describing the imaging and navigation problem and developing practical models of the sensors, then presenting a transformation technique to detect features within an image. Given a set of features, a statistical feature projection technique is developed which utilizes inertial measurements to predict vectors in the feature space between images. This coupling of the imaging and inertial sensors at a deep level is then used to aid the statistical feature matching function. The feature matches and inertial measurements are then used to estimate the navigation trajectory using an extended Kalman filter. After accomplishing a proper calibration, the image-aided inertial navigation algorithm is then tested using a combination of simulation and ground tests using both tactical and consumer- grade inertial sensors. While limitations of the Kalman filter are identified, the experimental results demonstrate a navigation performance improvement of at least two orders of magnitude over the respective inertial-only solutions
Dataset analysis for classifier ensemble enhancement
We developed three different methods for dataset analysis and ensemble enhance-
ment. They share the underlying idea that an accurate preprocessing and adap-
tation of the data can improve the system performance, without changing the
classification model. Correlation Score is a generic framework for assessing encoding
techniques by measuring the correlation between the encoded feature vectors and
the corresponding class labels; experiments show its effectiveness in discovering the
best encoding configurations between those tested, on a wide range of classification
domains. Multi-Resolution Complexity Analysis is a method for assessing the
local complexity inside a given domain. It is able to split a domain into regions
of different classification complexity, giving insights on the inner structure of the
populations inside the domain. Finally, Forests of Local Trees are a novel training
algorithm for ensemble classifiers. They are based on the concept of local trees:
classifiers trained with a bias toward a certain region of the domain. This bias
enhances the diversity inside the ensemble, leading to improved performance.
These three topics are meant as a foundation for a more complex framework, that
will eventually utilize them organically
Deep Learning for the Analysis of Latent Fingerprint Images
Latent fingerprints are fingerprint impressions unintentionally left on surfaces at a crime scene. The accuracy of latent fingerprint identification by latent fingerprint forensic examiners has been the subject of increased study, scrutiny, and commentary in the legal system and the forensic science literature. Errors in latent fingerprint matchingcan be devastating, resulting in missed opportunities to apprehend criminals or wrongful convictions of innocent people. Latent fingerprint comparison is increasingly relied upon by law enforcement to solve crime, and prosecute offenders. The increasing use of this service places new strains on the limited resources of the forensic science delivery system. Currently, latent examiners manually mark the region of interest (ROI) in latent fingerprints and use features manually identified in the ROI tosearch large databases of reference full fingerprints to identify a small number of potential matches for subsequent manual examination. Given the large size of law enforcement databases containing rolled and plain fingerprints, it is very desirable to perform latent fingerprint processing in a fully automated way.This dissertation proposes deep learning models and algorithms developed in the context of machine learning for automatic latent fingerprint image quality assessment, quality improvement, segmentation and matching. We also propose techniques that help speed-up convergence of a deep neural network and achieve a better estimation of the relation between a latent fingerprint image patch and its target class. A unified frequency domain based framework for latent fingerprint matching using image patches, as well as a novel latent fingerprint super-resolution model that uses a graph-total variation energy of latent fingerprints as a non-local regularizer for learning optimal weights for high quality image reconstruction, are also proposed. Using the deep learning models, we aim at providing an end-to-end automatic system that solves the problems inherent in latent fingerprint quality assessment, quality improvement, segmentation and matching
Towards Accurate Forecasting of Epileptic Seizures: Artificial Intelligence and Effective Connectivity Findings
L’épilepsie est une des maladies neurologiques les plus fréquentes, touchant près d’un
pourcent de la population mondiale. De nos jours, bien qu’environ deux tiers des patients
épileptiques répondent adéquatement aux traitements pharmacologiques, il reste qu’un tiers des
patients doivent vivre avec des crises invalidantes et imprévisibles. Quoique la chirurgie
d’épilepsie puisse être une autre option thérapeutique envisageable, le recours à la chirurgie de
résection demeure très faible en partie pour des raisons diverses (taux de réussite modeste, peur
des complications, perceptions négatives). D’autres avenues de traitement sont donc souhaitables.
Une piste actuellement explorée par des groupes de chercheurs est de tenter de prédire les crises à
partir d’enregistrements de l’activité cérébrale des patients. La capacité de prédire la survenue de
crises permettrait notamment aux patients, aidants naturels ou personnels médical de prendre des
mesures de précaution pour éviter les désagréments reliés aux crises voire même instaurer un
traitement pour les faire avorter. Au cours des dernières années, d’importants efforts ont été
déployés pour développer des algorithmes de prédiction de crises et d’en améliorer les
performances.
Toutefois, le manque d’enregistrements électroencéphalographiques intracrâniens (iEEG) de
longue durée de qualité, la quantité limitée de crises, ainsi que la courte durée des périodes
interictales constituaient des obstacles majeurs à une évaluation adéquate de la performance des
algorithmes de prédiction de crises. Récemment, la disponibilité en ligne d’enregistrements iEEG
continus avec échantillonnage bilatéral (des deux hémisphères) acquis chez des chiens atteints
d’épilepsie focale à l’aide du dispositif de surveillance ambulatoire implantable NeuroVista a
partiellement facilité cette tâche. Cependant, une des limitations associées à l’utilisation de ces
données durant la conception d’un algorithme de prédiction de crises était l’absence
d’information concernant la zone exacte de début des crises (information non fournie par les
gestionnaires de cette base de données en ligne). Le premier objectif de cette thèse était la mise
en oeuvre d’un algorithme précis de prédiction de crises basé sur des enregistrements iEEG canins
de longue durée. Les principales contributions à cet égard incluent une localisation quantitative
de la zone d’apparition des crises (basée sur la fonction de transfert dirigé –DTF), l’utilisation
d’une nouvelle fonction de coût via l’algorithme génétique proposé, ainsi qu’une évaluation
quasi-prospective des performances de prédiction (données de test d’un total de 893 jours). Les résultats ont montré une amélioration des performances de prédiction par rapport aux études
antérieures, atteignant une sensibilité moyenne de 84.82 % et un temps en avertissement de 10 %.
La DTF, utilisée précédemment comme mesure de connectivité pour déterminer le réseau
épileptique (objectif 1), a été préalablement validée pour quantifier les relations causales entre les
canaux lorsque les exigences de quasi-stationnarité sont satisfaites. Ceci est possible dans le cas
des enregistrements canins en raison du nombre relativement faible de canaux. Pour faire face
aux exigences de non-stationnarité, la fonction de transfert adaptatif pondérée par le spectre
(Spectrum weighted adaptive directed transfer function - swADTF) a été introduit en tant qu’une
version variant dans le temps de la DTF. Le second objectif de cette thèse était de valider la
possibilité d’identifier les endroits émetteurs (ou sources) et récepteurs d’activité épileptiques en
appliquant la swADTF sur des enregistrements iEEG de haute densité provenant de patients
admis pour évaluation pré-chirurgicale au CHUM. Les générateurs d’activité épileptique étaient
dans le volume réséqué pour les patients ayant des bons résultats post-chirurgicaux alors que
différents foyers ont été identifiés chez les patients ayant eu de mauvais résultats postchirurgicaux.
Ces résultats démontrent la possibilité d’une identification précise des sources et
récepteurs d’activités épileptiques au moyen de la swADTF ouvrant la porte à la possibilité d’une
meilleure sélection d’électrodes de manière quantitative dans un contexte de développement
d’algorithme de prédiction de crises chez l’humain.
Dans le but d’explorer de nouvelles avenues pour la prédiction de crises épileptiques, un
nouveau précurseur a aussi été étudié combinant l’analyse des spectres d’ordre supérieur et les
réseaux de neurones artificiels (objectif 3). Les résultats ont montré des différences
statistiquement significatives (p<0.05) entre l’état préictal et l’état interictal en utilisant chacune
des caractéristiques extraites du bi-spectre. Utilisées comme entrées à un perceptron multicouche,
l’entropie bispectrale normalisée, l’entropie carré normalisée, et la moyenne ont atteint des
précisions respectives de 78.11 %, 72.64% et 73.26%.
Les résultats de cette thèse confirment la faisabilité de prédiction de crises à partir
d’enregistrements d’électroencéphalographie intracrâniens. Cependant, des efforts
supplémentaires en termes de sélection d’électrodes, d’extraction de caractéristiques, d’utilisation
des techniques d’apprentissage profond et d’implémentation Hardware, sont nécessaires avant
l’intégration de ces approches dans les dispositifs implantables commerciaux.----------ABSTRACT
Epilepsy is a chronic condition characterized by recurrent “unpredictable” seizures. While
the first line of treatment consists of long-term drug therapy about one-third of patients are said to
be pharmacoresistant. In addition, recourse to epilepsy surgery remains low in part due to
persisting negative attitudes towards resective surgery, fear of complications and only moderate
success rates. An important direction of research is to investigate the possibility of predicting
seizures which, if achieved, can lead to novel interventional avenues.
The paucity of intracranial electroencephalography (iEEG) recordings, the limited number of
ictal events, and the short duration of interictal periods have been important obstacles for an
adequate assessment of seizure forecasting. More recently, long-term continuous bilateral iEEG
recordings acquired from dogs with naturally occurring focal epilepsy, using the implantable
NeuroVista ambulatory monitoring device have been made available on line for the benefit of
researchers. Still, an important limitation of these recordings for seizure-prediction studies was
that the seizure onset zone was not disclosed/available. The first objective of this thesis was to
develop an accurate seizure forecasting algorithm based on these canine ambulatory iEEG
recordings. Main contributions include a quantitative, directed transfer function (DTF)-based,
localization of the seizure onset zone (electrode selection), a new fitness function for the
proposed genetic algorithm (feature selection), and a quasi-prospective assessment of seizure
forecasting on long-term continuous iEEG recordings (total of 893 testing days). Results showed
performance improvement compared to previous studies, achieving an average sensitivity of
84.82% and a time in warning of 10 %.
The DTF has been previously validated for quantifying causal relations when quasistationarity
requirements are met. Although such requirements can be fulfilled in the case of
canine recordings due to the relatively low number of channels (objective 1), the identification of
stationary segments would be more challenging in the case of high density iEEG recordings. To
cope with non-stationarity issues, the spectrum weighted adaptive directed transfer function
(swADTF) was recently introduced as a time-varying version of the DTF. The second objective
of this thesis was to validate the feasibility of identifying sources and sinks of seizure activity
based on the swADTF using high-density iEEG recordings of patients admitted for pre-surgical monitoring at the CHUM. Generators of seizure activity were within the resected volume for
patients with good post-surgical outcomes, whereas different or additional seizure foci were
identified in patients with poor post-surgical outcomes. Results confirmed the possibility of
accurate identification of seizure origin and propagation by means of swADTF paving the way
for its use in seizure prediction algorithms by allowing a more tailored electrode selection.
Finally, in an attempt to explore new avenues for seizure forecasting, we proposed a new
precursor of seizure activity by combining higher order spectral analysis and artificial neural
networks (objective 3). Results showed statistically significant differences (p<0.05) between
preictal and interictal states using all the bispectrum-extracted features. Normalized bispectral
entropy, normalized squared entropy and mean of magnitude, when employed as inputs to a
multi-layer perceptron classifier, achieved held-out test accuracies of 78.11%, 72.64%, and
73.26%, respectively.
Results of this thesis confirm the feasibility of seizure forecasting based on iEEG recordings;
the transition into the ictal state is not random and consists of a “build-up”, leading to seizures.
However, additional efforts in terms of electrode selection, feature extraction, hardware and deep
learning implementation, are required before the translation of current approaches into
commercial devices
Computational Optimizations for Machine Learning
The present book contains the 10 articles finally accepted for publication in the Special Issue “Computational Optimizations for Machine Learning” of the MDPI journal Mathematics, which cover a wide range of topics connected to the theory and applications of machine learning, neural networks and artificial intelligence. These topics include, among others, various types of machine learning classes, such as supervised, unsupervised and reinforcement learning, deep neural networks, convolutional neural networks, GANs, decision trees, linear regression, SVM, K-means clustering, Q-learning, temporal difference, deep adversarial networks and more. It is hoped that the book will be interesting and useful to those developing mathematical algorithms and applications in the domain of artificial intelligence and machine learning as well as for those having the appropriate mathematical background and willing to become familiar with recent advances of machine learning computational optimization mathematics, which has nowadays permeated into almost all sectors of human life and activity
Primena inteligentnih sistema mašinske vizije autonomnog upravljanja železničkim vozilima
The railway is an important type of transport and has a significant
economic impact on the industry and people's everyday life. Due
to its capacities and complex infrastructure, it is necessary to work
on its constant development and improvement. Railway
automation requires the use of intelligent systems as a necessary
part of an autonomous railway vehicle. As from the point of view
of safe traffic, the existence of the object on the rail track and / or
in its vicinity represents a potential obstacle to the railway traffic,
and visibility has a very important role in correct and timely
detection of the object on the railway infrastructure, a key element
of autonomous railway vehicle is an obstacle detection system on
the part of the railway infrastructure, in conditions of reduced
visibility.
The subject of scientific research of this doctoral dissertation is the
application of intelligent machine vision systems in autonomous
train operation. For the purpose of detecting obstacles on the part
of the railway infrastructure in conditions of reduced visibility, a
thermal imaging camera and a night vision system are integrated
into the system, coupled with a developed advanced algorithm for
image processing with artificial intelligence tools. In addition, the
distance from the machine vision system to the detected object
was estimated. The operation of the system was tested in a series
of field experiments, at different locations, in different visibility
conditions and weather conditions, through realistic scenarios