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Ioannis Pitas

Researcher at Aristotle University of Thessaloniki

Publications -  826
Citations -  26338

Ioannis Pitas is an academic researcher from Aristotle University of Thessaloniki. The author has contributed to research in topics: Facial recognition system & Digital watermarking. The author has an hindex of 76, co-authored 795 publications receiving 24787 citations. Previous affiliations of Ioannis Pitas include University of Bristol & University of York.

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Approximate kernel extreme learning machine for large scale data classification

TL;DR: The proposed Approximate Kernel Extreme Learning Machine algorithm for Single-hidden Layer Feedforward Neural network training that can be used for large scale classification problems is able to scale well in both computational cost and memory, while achieving good generalization performance.
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Subclass discriminant Nonnegative Matrix Factorization for facial image analysis

TL;DR: The proposed method incorporates appropriate discriminant constraints in the NMF decomposition cost function in order to address the problem of finding discriminant projections that enhance class separability in the reduced dimensional projection space, while taking into account subclass information.
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Multidimensional Sequence Classification Based on Fuzzy Distances and Discriminant Analysis

TL;DR: A novel sequence representation, based on its fuzzy distances from optimal representative signal instances, called statemes, is proposed, and a novel modified clustering discriminant analysis algorithm minimizing the adopted criterion leading to the optimal discriminant sequence class representation in a low-dimensional space, respectively.
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Class-Specific Reference Discriminant Analysis With Application in Human Behavior Analysis

TL;DR: The proposed approach is tested on three problems relating to human behavior analysis: Face recognition, facial expression recognition, and human action recognition, since the proposed class-specific reference discriminant analysis outperforms kernel discriminantAnalysis, kernel spectral regression, and class- specific kernel discriminatory analysis, as well as support vector machine-based classification, in most cases.
Proceedings ArticleDOI

Hierarchical Face Clustering using SIFT Image Features

TL;DR: An algorithm to cluster face images found in video sequences is proposed, and a novel method for creating a dissimilarity matrix using SIFT image features is introduced, which yields the clustering result.