George A. Triantafyllidis

Aalborg University · Department of Architecture, Design and Media Technology

This study explores how lighting can be employed as a visual language to enhance communication between the space and its users and develop a design framework for educational spaces. A primary school is used as a case study to apply the proposed design framework. The study focuses on lighting interventions in existing educational spaces to support d...

This paper presents the results of ‘Light4Health’ (L4H), a three-year EU Erasmus+ Strategic Partnership grant project (2019-2021), which investigated, systematized and taught health-related research on the impact of natural and artificial light on human health and well-being relevant to indoor lighting design. The objective was to re-think evidence...

Outdoor lighting has mainly been approached as an engineering subject throughout its history. The current urban lighting requirements are established upon factors which mainly refer to motorised traffic dynamics. As a consequence, excessive lighting levels are found in the city environments with a negative impact on the human as well as the environ...

Light is the foundation of the visual perceptual process that initiates the evaluation of the surrounding area. Linked to various aspects and rhythms of the body, light connects us to both the natural environment and the interior space. The process of perceiving and assessing space for children and adults with different viewing heights and viewing...

A holistic approach to daylight dynamics in our built environment can have beneficial outcomes for both physiological and visual effects on humans. Simulations of how daylight variables affect light levels on the horizontal work plane are compared to their physiological effects, measured as melanopic EDI (Melanopic Equivalent Daylight Illuminance)...

Urban development projects are often 1opposed by residents due to a lack of sense of ownership over the project. This study is a methodological approach in creating interactive lighting art installations in virtual environments to stimulate this sense of ownership. The study is part of the Brighter Brunnshög project, which is the initial stage of t...

The research presented in this paper revolves around the development of an interactive light installation called NEO-David. The focus is on the development of kinetic light within the boundaries of real-time generated anthropomorphic form. The case study seeks to address the issues related to democratic aspects of art and participatory artistic dev...

Despite significant recent advances in the field of head pose estimation and facial expression recognition, raising the cognitive level when analysing human activity presents serious challenges to current concepts. Motivated by the need of generating comprehensible visual representations from different sets of data, we introduce a system capable of...

An approach build on discriminative random regression forests was followed in order to achieve fast, accurate and reliable estimation of head pose in uncontrolled environment. Data representing the changes of a person's head direction, concerning two Degrees of Freedom (DOF), pitch and yaw, are collected and stored adopting a lightweight data excha...

Real-time multimedia content production, because of its delay-sensitive nature, requires fast and precise control by the user. This is commonly achieved by specialized application-specific physical controllers, with steep learning curves. In our work, we propose using the inputs from Microsoft Kinect as a controller interface. Introduced as a peri...

The recognition of facial expressions is important for the perception of emotions. Understanding emotions is essential in human communication and social interaction. Children with autism have been reported to exhibit deficits in the recognition of affective expressions. Their difficulties in understanding and expressing emotions lead to inappropria...

This paper presents a natural user interface system based on multimodal human computer interaction, which operates as an intermediate module between the user and the operating system. The aim of this work is to demonstrate a multimodal system which gives users the ability to interact with desktop applications using face, objects, voice and gestures...

This paper presents a complete system for multiple object detection and classification in a 3D scene using an RGB-D sensor such as the Microsoft Kinect sensor. Successful multiple object detection and classification are crucial features in many 3D computer vision applications. The main goal is making machines see and understand objects like humans...

In this paper we present a natural user interface system. The device utilized for achieving natural interaction is the MS-Kinect which provides RGB, depth & audio signal. Our system is based on the theory of multimodal interaction and provides the ability to the user to interact simultaneously with different applications using vocal commands and ge...

This paper presents a novel system that is fusing efficient and state-of-the-art techniques of stereo vision and machine learning, aiming at object detection and recognition. To this goal, the system initially creates depth maps by employing the Graph-Cut technique. Then, the depth information is used for object detection by separating the objects...

In this paper a novel frequency domain technique estimating the significance of blocking artifacts in images coded using the Discrete Cosine Transform is proposed. First a gradient image is computed which is then split into blocks. For each block, the blocking artifacts in the horizontal and vertical directions are detected by comparing ratios obta...

Extending visual communications to the third dimension (3D) has been a dream over decades. The ultimate goal of the viewing experience is to create the illusion of a real environment in its absence. However limitations of visual quality and user acceptance prevented the development of relevant mass markets so far. Recent achievements in research an...

The recent advances in Image Based Rendering (IBR) has pioneered a new technology, named Free-View Television (FTV), in which the viewers select freely the viewing position and angle of the transmitted multi-view video. In Free-View Television, a person might record a personal video of this arbitrarily selected view and misuse this content, therefo...

The aim of this study is to build a Web-based virtual tour system, focused at the presentation of archaeological sites. The proposed approach is comprised of powerful techniques such as multiview 3D reconstruction, omnidirectional viewing based on panoramic images, and their integration with GIS technologies. In the proposed method, the scene is ca...

Research efforts on 3DTV technology have been strengthened worldwide recently, covering the whole media processing chain from capture to display. Different 3DTV systems rely on different 3D scene representations that integrate various types of data. Efficient coding of these data is crucial for the success of 3DTV. Compression of pixel-type data in...

The recent advances in Image Based Rendering (IBR) has pioneered a new technology, free view point television, in which TV-viewers select freely the viewing position and angle by the application of IBR on the transmitted multi-view video. In this paper, exhaustive tests were carried out to conclude to the best possible watermarking for free-view te...

The recent advances in image based rendering (IBR) has pioneered a new technology, free view point television, in which TV-viewers select freely the viewing position and angle by the application of IBR on the transmitted multi-view video. In this paper, exhaustive tests were carried out to conclude to the best possible watermarking for free-view te...

Ultrasound imaging allows the evaluation of the degree of emergency of a patient. However, in many situations no experienced sonographer is available to perform such echography. To cope with this issue, the OTELO project “mObile Tele-Echography using an ultra-Light rObot” (OTELO) aims to develop a fully integrated end-to-end mobile tele-echography...

In this paper, a software-based system for the real-time synchronization of images captured by a low-cost camera framework is presented. It is most well suited for cases where special hardware cannot be utilized (e.g. remote or wireless applications) and when cost efficiency is critical. The proposed method utilizes messages to establish a consensu...

Mobile interconnectivity and telemedicine are important issues for achieving effectiveness in health care, since medical information can be transmitted faster and physicians can make diagnoses and treatment decisions faster. In this context, the OTELO project (OTELO, 2001) aims to develop a fully integrated end-to-end mobile tele-echography system...

A technological revolution in health care is underway, triggered by advances in information technology (IT) including modern telecommunications, information processing capability and miniaturised health diagnostic technology. This powerful combination permits advances in high-bandwidth applications for clinic and patient-based telemedicine techniqu...

A novel frequency domain,technique for image blocking ar- tifact reduction is presented in this paper. For each block, its DC and AC coe‐cients are recalculated for artifact reduction. To achieve this, a closed form representation of the optimal correction of the DCT coef- flcients is produced by minimizing a novel enhanced form of the Mean Squared...

Ultrasound imaging allows the evaluation of the degree of emergency of a patient. However, in some instances, a well-trained sonographer is unavailable to perform such echography. To cope with this issue, the Mobile Tele-Echography Using an Ultralight Robot (OTELO) project aims to develop a fully integrated end-to-end mobile tele-echography system...

Despite its growing age, the JPEG is among the most popular choices as a standard compression scheme for continuous-tone still images. In this paper, a novel technique is proposed to alleviate the blocking artifacts that usually occur in JPEG coded images especially at low bit rates. The proposed algorithm consists of two stages: firstly, the AC co...

Multiview image sequence processing has been the focus of considerable attention in recent literature. This paper presents an efficient technique for object-based rigid and non-rigid 3D motion estimation, applicable to problems occurring in multiview image sequence coding applications. More specifically, a neural network is formed for the estimatio...

A novel frequency-domain technique for image blocking artifact detection and reduction is presented. 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 (DCT)...

Stereoscopic image sequence processing has been the focus of considerable attention in recent literature for videoconference applications. A novel Bayesian scheme is proposed in this paper, for the segmentation of a noisy stereoscopic image sequence. More specifically, occlusions and visible foreground and background regions are detected between th...

A novel combined frequency and spatial domain method is presented in this paper for blockiness reduction for low bit rate compressed images. The method consists of two stages: in the first, better estimates of the reconstructed DCT coefficients are obtained based on their observed probability distribution. In the second, an efficient postprocessing...

A novel combined frequency and spatial domain method is presented in this paper for blockiness reduction for low bit rate compressed images. The method consists of two stages: in the first, better estimates of the reconstructed DCT coefficients are obtained based on their observed probability distribution. In the second, an efficient postprocessing...

A novel technique is proposed to reduce the blocking artifacts detected in the JPEG coded images, especially in low bit rates. The proposed algorithm is consisting of two stages: firstly, the AC coefficients are estimated based on their observed probability distribution and secondly, a postprocessing scheme consisting of a region classification alg...

A novel hybrid frequency and spatial domain method is presented for blockiness reduction in low bit rate compressed images. The proposed method consists of two stages acting complementarily. In the first, better estimates of the reconstructed DCT coefficients are obtained based on their observed probability distribution. In the second, an efficient...

An efficient technique based on the Bayes test is introduced in this paper for the identification of the occlusion and visible background and foreground areas in a noisy stereoscopic image pair. Four hypotheses are used for the formulation of a compound Bayes decision rules. Experimental results illustrating the performance of the proposed techniqu...

A novel combined frequency and spatial domain method is presented in this paper for blockiness reduction for low bit rate compressed images. The method consists of two stages: in the first, better estimates of the reconstructed DCT coefficients are obtained based on their observed probability distribution. In the second, an efficient postprocessing...

An efficient technique based on the Bayes test is introduced, for detecting occlusions in a noisy stereoscopic image pair. Two hypotheses are used for the formulation of the Bayes decision rules: the first describes the displaced areas while the other describes the occlusion areas. Experimental results illustrating the performance of the proposed t...

A novel frequency domain technique for image blocking artifact detection is presented. The algorithm 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 DCT coefficients are modeled by a Laplacian probabi...

A novel frequency domain technique for image blocking artifact detection is presented in this paper. The algorithm 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 DCT coefficients are modeled by a Lap...

A novel frequency domain technique for image blocking artifact reduction is presented. For each block, its DC and AC coefficients are recalculated for artifact reduction. To achieve this, a closed form representation of the optimal correction of the DCT coefficients is produced by minimizing a novel enhanced form of the mean squared difference of s...

A novel frequency domain technique for image blocking artifact detection is presented. The algorithm 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 DCT coefficients are modeled by a Laplacian probabi...

Discrete wavelet transforms are widely used for lossless image compression, The overall performance of these schemes may be further improved by properly designing efficient entropy coders. A novel technique for the implementation of context-based adaptive arithmetic entropy coding is presented in this paper. This technique is based on the predictio...

An efficient technique based on the Bayes test is introduced in this paper, for the identification of the occlusion and visible background and foreground areas in a noisy stereoscopic image pair. Four hypotheses are used for the formulation of compound Bayes decision rules. Experimental results illustrating the performance of the proposed technique...

Significant progress has recently been made in lossless im- age compression using discrete wavelet transforms. The overall performance of these schemes may be further im- proved by properly designing efficient entropy coders. In this paper a new technique is introduced for the implemen- tation of context-based adaptive arithmetic entropy coding. Th...

The overall performance of discrete wavelet transforms for lossless image compression may be further improved by properly designing efficient entropy coders. In this paper a novel technique is proposed for the implementation of context-based adaptive arithmetic entropy coding. It is based on the prediction of the value of the current transform coef...

Efficient techniques are introduced in this paper for the identification of the occlusion and visible background and foreground areas in a noisy stereoscopic image pair. Three different Bayes decision methods are tested for this purpose. The first, and uses three hypotheses for the formulation of the Bayes decision rules, adopting the right image a...

A Bayesian scheme is proposed for the identification of the occlusion and visible background and foreground areas in a noisy stereoscopic image pair. Three hypotheses are used for the formulation of Bayes decision rules: the first describes the visible foreground areas, the second describes the visible background areas and the last describes the oc...

Significant progress has recently been made in lossless image compression using discrete wavelet transforms. The overall performance of these schemes may be further improved by properly designing efficient entropy coders. A new technique is introduced for the implementation of context based adaptive arithmetic entropy coding. This technique is base...

Despite its growing age, the JPEG is among the most popular choices as a standard compression scheme for continuous-tone still images. In this paper, a novel technique is proposed to alleviate the blocking artifacts that usually occur in JPEG coded images especially at low bit rates. The proposed algorithm consists of two stages: firstly, the AC co...

When ICT technologies were implemented in schools gradual changes started to take place in the organisation of education, in the form and method of teaching, the role of teacher, the class organising. One of the fundamental changes took place in the organization of the classroom, which could not remain the same. In this paper we shall present the c...