Dimitrios Tzovaras

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In the present paper a face recognition technique is developed based on depth and colour information. The main objective of the paper is to evaluate three different approaches (colour, depth, combination of colour and depth) for face recognition and quantify the contribution of depth. The proposed face recognition technique is based on the implementation of(More)
The optimal predictors of a lifting scheme in the general n-dimensional case are obtained and applied for the lossless compression of still images using first quincunx sampling and then simple row-column sampling. In each case, the efficiency of the linear predictors is enhanced nonlinearly. Directional postprocessing is used in the quincunx case, and(More)
A novel frequency-domain technique for image blocking artifact detection and reduction is presented in this paper. The algorithm first detects the regions of the image which present visible blocking artifacts. This detection is performed in the frequency domain and uses the estimated relative quantization error calculated when the discrete cosine transform(More)
In this study we examined the effects of intermittent short-duration Galvanic Vestibular Stimulation (GVS) during a multisensory perturbation of posture in young and elderly adults. Twelve young (24.91±6.44 years) and eleven elderly (74.8±6.42 years) participants stood upright under two task conditions: (a) quiet standing and (b) standing while receiving(More)
In this paper, a 3D shape-based approach is presented for the efficient search, retrieval, and classification of protein molecules. The method relies primarily on the geometric 3D structure of the proteins, which is produced from the corresponding PDB files and secondarily on their primary and secondary structure. After proper positioning of the 3D(More)
Multiresolution block matching methods for both monocular and stereoscopic image sequence coding are evaluated. These methods are seen to drastically reduce the amount of processing needed for block correspondence without seriously a ecting the quality of the reconstructed images. The evaluation criteria are the prediction error and the speed of the(More)
This paper proposes an innovative gait identification and authentication method based on the use of novel 2-D and 3-D features. Depth-related data are assigned to the binary image silhouette sequences using two new transforms: the 3-D radial silhouette distribution transform and the 3-D geodesic silhouette distribution transform. Furthermore, the use of a(More)
This paper presents a novel object-based method for the generation of a stereoscopic image sequence from a monoscopic video, using bidirectional two–dimensional motion estimation for the recovery of rigid motion and structure and a Bayesian framework to handle occlusions. The latter is based on extended Kalman filters and an efficient method for reliably(More)
In this paper, a fuzzy expert system (FES) for the detection of the physiological manifestations of extreme hypovigilance is presented. A large number of features that describe the eyelid activity of drivers is examined, and fuzzy logic is used for the fusion of the most prominent features to not only increase the accident prediction accuracy but also(More)
This paper presents the work that has been carried out within the SENSATION Integrated Project [1] concerning the prediction of sleep onset for drivers aiming to provide an effective measure for sleep related accident prevention. Indicators that have been proven to be the most relevant to the physiological manifestation of hypovigilance were examined and(More)