Academic Positions

  • Present 2014

    Assistant Professor (tenure-track)

    Cyprus University of Technology, Department of Multimedia and Graphic Arts

  • 2014 2010

    Lecturer (tenure-track, equivalent to U.S. Assistant Professor)

    Cyprus University of Technology, Department of Multimedia and Graphic Arts

  • 2010 2009

    Visiting Lecturer

    University of Cyprus, Department of Computer Science

Education & Training

  • Ph.D. 2008

    Ph.D. in Computer Science

    University of Southern California, Viterbi School of Engineering, Department of Computer Science

  • M.Sc.2003

    Master in Computer Science with specialization in Multimedia and Creative Technologies (GPA 394/4.00)

    University of Southern California, Viterbi School of Engineering, Department of Computer Science

  • B.Sc.2001

    Bachelor in Computing Information Systems (First-class honors)

    University of Manchester, Department of Computer Science

Honors, Awards and Grants

  • OCT 2014
    Support International Networking Mobility Grant
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    Project Title: Face 2 Face Meetings at H2020 Conference ICT 2014 Brokerage Event
    Contract number: METPA/SYND/1013/36
    Duration: 5 days
    Amount awarded to Cyprus University of Technology: € 1,500
    Funding body: Cyprus Research Promotion Foundation
    Principal Investigator: C. Poullis
    Description: The primary objective is to attend the ICT 2014 Brokerage event and establish a wider European and International network in view of the upcoming Call-for-Proposals of the European Horizon 2020 program.
  • MAR 2014
    Micro Media Grant
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    Project Title: Marie Curie Alumni Association Micro Media Grant
    Duration: 1 month (April 2014)
    Amount awarded to Cyprus University of Technology: € 250
    Funding body: Marie Curie Alumni Association
    Principal Investigator: C. Poullis
    Description: Design and production of posters, flyers and hand-outs; submission of papers to scientific conferences and journals; edition and writing of books; development and production of videos; development and maintenance of web pages; subscriptions to online services.
  • NOV 2013
    Support International Networking Mobility Grant
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    Project Title: Face 2 Face Meetings at H2020 Conference ICT 2013 Brokerage Event
    Contract number: METPA/SYND/1013/01
    Duration: 2 days
    Amount awarded to Cyprus University of Technology: € 1,500
    Funding body: Cyprus Research Promotion Foundation
    Principal Investigator: C. Poullis
    Description: The primary objective is to attend the ICT 2013 Brokerage event and establish a wider European and International network in view of the upcoming Call-for-Proposals of the European Horizon 2020 program.
  • SEP 2012
    New Infrastructure Grant
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    Project Title: A State-of-the-Art VR CAVE facility for the Advancement of Multi-Disciplinary Research & Development in Cyprus
    Contract number: DESMH 2009-2010 - IPE/NEKYP/0311/02
    Duration: 36 months (starting date 02 April 2012)
    Amount awarded to Cyprus University of Technology: € 499,887
    Funding bodies: European Union Structural Funds & Cyprus Research Promotion Foundation
    Principal Investigator: C. Poullis
    Website: http://www.vrcave.com.cy
    Description: The primary objective of the project is the establishment of a state-of-the-art VR CAVE facility in Cyprus and the implementation of three projects whose success depends on the use of this technology.
  • APR 2012
    Microsoft Imagine Cup (Game Design) Award
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    Supervisor of winning team at the local Microsoft Imagine Cup 2012 Competition (Game Design division), Limassol, Cyprus.
  • APR 2011
    Microsoft Imagine Cup (Software Design) Award
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    Supervisor of winning team at the local Microsoft Imagine Cup 2011 Competition (Software Design division), Nicosia, Cyprus.
  • SEP 2010
    FP7 PEOPLE Marie Curie Actions IRG Fellowship Grant
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    Project Title: 3DUNDERWORLD - Rapid Scanning and Automatic 3D Reconstruction of Underwater Sites
    Contract number: 268256
    Duration: 48 months (starting date 01/12/2010)
    Amount awarded to Cyprus University of Technology: € 100,000
    Funding body: European Union
    Principal Investigator: C. Poullis
    Website: http://www.3dunderworld.org
    Description: The primary objective of the project is to develop techniques for rapid data acquisition suitable for a range of applications and in particular for underwater archeology.
  • MAR 2009
    Audience Choice Award - Best Sketch Paper Award
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    Audience Choice Award - Best Sketch Paper for the paper "Automatic Creation of Massive Virtual Cities" at IEEE VR 2009, Lafayette, USA.
  • NOV 2007
    Best Fast-Forward Poster Presentation Award
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    Best Fast-Forward Poster Presentation Award for the paper "Linear Feature Extraction Using Perceptual Grouping And Graph-Cuts" at ACM GIS 2007, Seattle, USA.
  • 2005 - 2009
    Teaching Assistantship/Scholarship
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    Awarded by the Department of Computer Science, University of Southern California, Los Angeles, USA.
  • 2003 - 2005
    Research Assistantship/Scholarship
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    Awarded by the Institute for Creative Technologies, University of Southern California, Los Angeles, USA.
  • 2001 - 2003
    Post-Graduate Studies Scholarship
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    Awarded by the University of Southern California and Amideast, Los Angeles, USA.

Laboratory Personel

Aimilia Tzanavari

Research Associate (HCI)

Kyriakos Herakleous

Research Associate (Computer Vision/Graphics)

Charalambos Poullis

Lab Director

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Maria Christofi

Research Associate (2D/3D Artist)

Vaso Constantinou

[Alumni] Fall 2013 Intern (Undergraduate Student)

Maria Mitsi

[Alumni] Summer, Fall 2013 Intern (Undergraduate Student)

Fransesca Sella

[Alumni] Summer, Fall 2013 Intern (Undergraduate Student)

Konstantinos Koumi

[Alumni] Summer 2013 Intern (Undergraduate Student)

Marios Kleanthous

[Alumni] Summer 2013 Intern (Undergraduate Student)

Josephine Antoniou

[Alumni] Postdoctoral Fellow

Fernando Loizides

[Alumni] Research Associate

Evangelos Christofi

[Alumni] Summer 2013 Intern (Graduate Student)

Constantinos Terlikkas

Summer, Fall 2013 Intern (Graduate Student)

Skevi Matsentidou

Summer, Fall 2013 Intern (Graduate Student)

Irene Katsouri

Summer, Fall 2013 Intern (Graduate Student)

Despo Prokopiou

Lab Assistant

Immersive and Creative Technologies Research Lab

The Immersive and Creative Technologies Lab conducts fundamental and applied research in the area lying at the intersection of computer vision and computer graphics.

New knowledge and other research outcomes resulting from the research at the ICT lab are disseminated through teaching, research projects, and collaboration with the industry.

For more information: http://www.theICTlab.org

Research Projects

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    A State-of-the-Art VR CAVE facility for the Advancement of Multi-Disciplinary Research & Development in Cyprus - Research Promotion Foundation, (2012-2014)

    Project website: http://www.vrcave.com.cy

    Currently, there is no VR CAVE facility in Cyprus, neither in the private nor the public sector. Researchers involved in areas which require the use of such specialized equipment rely on small-scale, portable, and usually handheld VR systems for conducting their research experiments which quite often is inadequate for testing and validating their work.

    The VR-CAVE project addresses these technological limitations and difficulties and seeks the solution in the establishment of the first state-of-the-art VR (Virtual Reality) CAVE (Computer Automated Virtual Environment) for facilitating the advancement of multi-disciplinary research and development in Cyprus.

    In particular, the project aims to bridge the gap between the various disciplines by leveraging the common research methodologies and techniques employed by all disciplines, through the establishment of a state-of-the-art multimodal interaction VR-CAVE facility which enables users to collaboratively engage in an interactive, real-time and visually immersive environment.

    The project NEKYP/0311/02 "A State-of-the-Art VR CAVE facility for the Advancement of Multi-Disciplinary Research & Development in Cyprus" has received €499,887 in funding from the Cyprus Research Promotion Foundation (RPF) and the EU Structural Funds.

    The duration of the project is from April 2nd, 2012 to October 2nd, 2014.

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    Rapid Scanning and Automatic 3D Reconstruction of Underwater Sites

    Project website: http://www.3dunderworld.org

    The primary objective of this project is the development of an innovative hardware and software solution for the rapid scanning and 3D reconstruction of objects. The system will address the complexities and problems associated with the data acquisition, processing and reconstruction of objects situated underwater. The development of such a system will enhance the techniques available to underwater archaeologists and exploration groups in general, since it will significantly accelerate the documentation and mapping process.

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Visualizing and Assessing Hypotheses in Marine Archaeology in a VR CAVE Environment

Irene Katsouri, Aimilia Tzanavari, Kyriakos Herakleous, Charalambos Poullis
Journal Paper ACM Journal on Computing and Cultural Heritage

Abstract

The understanding and reconstruction of a wreck’s formation process can be a complicated procedure that needs to take into account many interrelated components. The Cypriot archaeologists investigating the 4th century BC, Mazotos shipwreck are unable to interact easily and intuitively with the recorded data, a fact that impedes visualization and reconstruction and subsequently delays the evaluation of their hypotheses. An immersive 3D visualization application that utilizes a VR CAVE was developed, with the intent to enable researchers to mine the wealth of information this ancient shipwreck has to offer. Through the implementation and evaluation of the proposed application, this research seeks to investigate whether such an environment can aid the interpretation and analysis process and ultimately serve as an additional scientific tool for marine archeology.

Tensor-Cuts: A simultaneous multi-type feature extractor and classifier and its application to road extraction from satellite images

Charalambos Poullis
Journal Paper ISPRS Journal of Photogrammetry and Remote Sensing, Elsevier

Abstract

Many different algorithms have been proposed for the extraction of features with a range of applications. In this work, we present Tensor-Cuts: a novel framework for feature extraction and classification from images which results in the simultaneous extraction and classification of multiple feature types (surfaces, curves and joints). The proposed framework combines the strengths of tensor encoding, feature extraction using Gabor Jets, global optimization using Graph-Cuts, and is unsupervised and requires no thresholds. We present the application of the proposed framework in the context of road extraction from satellite images, since its characteristics makes it an ideal candidate for use in remote sensing applications where the input data varies widely. We have extensively tested the proposed framework and present the results of its application to road extraction from satellite images.

3DUNDERWORLD-SLS: An Open-Source Structured-Light Scanning System for Rapid Geometry Acquisition

Kyriakos Herakleous, Charalambos Poullis
Other (Technical Report) ICT-TR-2014-01

Abstract

Recently, there has been an increase in the demand of virtual 3D objects representing real-life objects. A plethora of methods and systems have already been proposed for the acquisition of the geometry of real-life objects ranging from those which employ active sensor technology, passive sensor technology or a combination of various techniques. In this paper we present the development of a 3D scanning system which is based on the principle of structured-light, without having particular requirements for specialized equipment. We discuss the intrinsic details and inherent difficulties of structured-light scanning techniques and present our solutions. Finally, we introduce our open-source scanning system "3DUNDERWORLD-SLS" which implements the proposed techniques. We have performed extensive testing with a wide range of models and report the results. Furthermore, we present a comprehensive evaluation of the system and a comparison with a high-end commercial 3D scanner.

User experience observations on factors that affect performance in a road crossing training application for children using the CAVE

Aimilia Tzanavari, Skevi Matsentidou, Chris G. Christou, Charalambos Poullis
Conference Papers 1st International Conference on Learning and Collaboration Technologies LCT2014, held as part of HCI International 2014

Abstract

Each year thousands of pedestrian get killed in road accidents and millions are non-fatally injured. Many of these involve children and occur when crossing at or between intersections. It is more difficult for children to understand, assess and predict risky situations, especially in settings that they don’t have that much experience in, such as in a city. Virtual Reality has been used to simulate situations that are too dangerous to practice in real life and has proven to be advantageous when used in training, aiming at improving skills. This paper presents a road-crossing application that simulates a pedestrian crossing found in a city setting. Children have to evaluate all given pieces of information (traffic lights, cars crossing, etc.) and then try to safely cross the road in a virtual environment. A VR CAVE is used to immerse children in the city scene. User experience observations were made so as to identify the factors that seem to affect children’s performance. Results indicate that the application was well received as a learning tool and that gender; immersion and traffic noise seem to affect children’s performance.

Immersive Visualizations in a VR Cave Environment for the Training and Enhancement of Social Skills for Children with Autism

Skevi Matsentidou, Charalambos Poullis
Conference Papers 9th International Conference on Computer Vision Theory and Applications

Abstract

Autism is a complex developmental disorder characterized by severe impairment in social, communicative, cognitive and behavioral functioning. Several studies investigated the use of technology and Virtual Reality for social skills training for people with autism with promising and encouraging results (D. Strickland, 1997; Parsons S. & Cobb S., 2011). In addition, it has been demonstrated that Virtual Reality technologies can be used effectively by some people with autism, and that it had helped or could help them in the real world; (S. Parsons, A. Leonard, P. Mitchell, 2006; S. Parsons, P. Mitchell, 2002). The goal of this research is to design and develop an immersive visualization application in a VR CAVE environment for educating children with autism. The main goal of the project is to help children with autism learn and enhance their social skills and behaviours. Specifically, we will investigate whether a VR CAVE environment can be used in an effective way by children with mild autism, and whether children can benefit from that and apply the knowledge in their real life. The training will focus in situations of real life which are difficult or impossible to explain to children with the known methods of treatment. Like an unsafe situation or a situation where the child must have an experience of it in order to learn how to act (e.g. crossing the road).

Towards a More Effective Way of Presenting Virtual Reality Museums Exhibits

Constantinos Terlikkas, Charalambos Poullis
Conference Papers 9th International Conference on Computer Vision Theory and Applications

Abstract

In this work, we present the design, development and comparison of two immersive applications with the use of Virtual Reality CAVE technology: a virtual museum following the traditional paradigm for the museum exhibit placement and a virtual museum where no spatial restrictions exist. Our goal is to identify the most effective method of arranging museum exhibits when no constraints are present. Additionally we will present the significance of the folklore museum in cyprus. Since this would affect the design process.

A Framework for Automatic Modeling from Pointcloud Data

Charalambos Poullis
Journal Paper IEEE Transactions on Pattern Analysis and Machine Intelligence

Abstract

We propose a complete framework for the automatic modeling from pointcloud data. Initially, the pointcloud data is pre-processed into manageable datasets, which are then separated into clusters using a novel two-step, unsupervised clustering algorithm. The boundaries extracted for each cluster are then simplified and refined using a fast energy minimization process. Finally, 3D models are generated based on the roof outlines. The proposed framework has been extensively tested and the results are reported.

Improving Augmented Reality Applications with Optical Flow

Kyriakos Herakleous, Charalambos Poullis
Conference Papers IEEE International Conference on Image Processing

Abstract

This paper presents an augmented reality application framework which does not require specialized hardware or pre-calibration. Features extracted using SURF are matched between consecutive frames in order to determine the motion of the detected known object with respect to the camera. Next, a bi-directional optical flow algorithm is used to maintain the performance of the system to real- time. The system has been tested on two case studies, a children’s book and advertisement, and the results are reported.

Environment-Aware Design For Underwater 3D-Scanning Application

Josephine Antoniou, Charalambos Poullis
Other (Technical Report) ICT-TR-2012-03

Abstract

Underwater archaeologists and exploration groups often face a challenge with the documentation and mapping process, which must take place underwater and be able to accurately capture and reconstruct the specific archaeological site. The automation of the scanning and reconstructing process is quite desirable for the underwater archaeologists, however, such automation entails quite a few hurdles from a technological perspective, in terms of data acquisition, processing and final reconstruction of the objects situated underwater. This paper focuses on the design of the 3D scanning application, for the purpose of reconstructing the underwater objects/scenes, such that it is environment-aware. By environment-aware the paper refers to the identification of aspects of an underwater environment that need to be considered in a 3D scanning process and, furthermore, the designing of a system that considers these aspects when scanning objects/scenes found in underwater environments. In this process, several decisions need to be made, with regards to the setup, the method and the analysis, considering issues that may arise in such environments.

Addressing lens distortion through the use of feed-forward neural networks for calibrating underwater scenes

Josephine Antoniou, Charalambos Poullis
Other (Technical Report) ICT-TR-2012-02

Abstract

Underwater archaeologists often face a challenge with the documentation process, which must take place underwater and be able to accurately capture and reconstruct an archaeological site. The automation of the scanning and reconstructing process is desirable, however, it entails quite a few hurdles from a technological perspective, in terms of data acquisition, processing and final reconstruction of the objects situated underwater. This paper focuses on the system calibration process, as the first step towards a successful automation attempt, and in particular on lens distortion and how to eliminate this from the calibration process. Existing analytical solutions that approximate lens distortion values, might not be able to capture such distortions faithfully, and in underwater environments where the water’s refractive index causes a magnification of image features, the analytical approximation of distortion values becomes even more challenging. The neural network approach proposed aims to simplify the calibration procedure for such environments by eliminating lens distortion prior to system calibration, without compromising precision in the subsequent calibration process.

Improving Augmented Reality Applications on Commodity Hardware With Optical Flow

Kyriakos Herakleous, Charalambos Poullis
Other (Technical Report) ICT-TR-2012-01

Abstract

This paper presents an augmented reality application framework which does not require specialized hardware or pre-calibration. Features extracted using SURF are matched between consecutive frames in order to determine the motion of the detected known object with respect to the camera. Next, a bi-directional optical flow algorithm is used to maintain the performance of the system to realtime. The system has been tested on two case studies, a children’s book and advertisement, and the results are reported.

Digitizing the Parthenon: Estimating Surface Reflectance under Measured Natural Illumination

Paul Debevec, Chris Tchou, Andrew Gardner, Tim Hawkins, Charalambos Poullis , Jessi Stumpfel, Andrew Jones, Nathaniel Yun, Per Einarsson, Therese Lundgren, Marco Fajardo, Philippe Martinez
Book Chapter CRC Press | July 28, 2011 | ISBN-13: 978-1-43-982173-2
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Digital Imaging for Cultural Heritage Preservation: Analysis, Restoration, and Reconstruction of Ancient Artworks

This edition presents the most prominent topics and applications of digital image processing, analysis, and computer graphics in the field of cultural heritage preservation. The text assumes prior knowledge of digital image processing and computer graphics fundamentals. Each chapter contains a table of contents, illustrations, and figures that elucidate the presented concepts in detail, as well as a chapter summary and a bibliography for further reading. Well-known experts cover a wide range of topics and related applications, including spectral imaging, automated restoration, computational reconstruction, digital reproduction, and 3D models.

3D Reconstruction of Urban Areas

Charalambos Poullis, Suya You
Conference Papers IEEE 3D Imaging, Modeling, Processing, Visualization, Transmission (3DIM/3DPVT in cooperation with Eurographics)

Abstract

Virtual representations of real world areas are increasingly being employed in a variety of different applications such as urban planning, personnel training, simulations, etc. Despite the increasing demand for such realistic 3D representations, it still remains a very hard and often manual process. In this paper, we address the problem of creating photorealistic 3D scene models for large-scale areas and present a complete system.
The proposed system comprises of two main components: (1) A reconstruction pipeline which employs a fully automatic technique for extracting and producing high-fidelity geometric models directly from Light Detection and Ranging (LiDAR) data and (2) A flexible texture blending technique for generating high-quality photorealistic textures by fusing information from multiple optical sensor resources. The result is a photorealistic 3D representation of large-scale areas(city-size) of the real-world.

Delineation and Geometric Modeling of Road Networks

Charalambos Poullis, Suya You
Journal Paper ISPRS Journal of Photogrammetry and Remote Sensing, Elsevier

Abstract

In this work we focus on the automatic and reliable detection and extraction of transportation networks from remote sensor data including aerial photographs, satellite images, and LiDAR. We present an integrated solution that merges the strengths of perceptual grouping theory(Gabor filters, tensor voting) and segmentation(global optimization by graph-cuts), under a unified framework to address the challenging problem of automated feature detection, classifcation and extraction.
The proposed approach leverages the multi-scale, multiorientation capabilities of Gabor filters for the inference of geospatial features, the effective and robust handling of noisy, incomplete data of tensor voting for the feature classification and the fast and efficient optimization of graph cuts for the segmentation and labeling of road features.

Automatic Reconstruction of Cities from Remote Sensor Data

Charalambos Poullis, Suya You
Conference Papers IEEE Computer Vision and Pattern Recognition

Abstract

In this paper, we address the complex problem of rapid modeling of large-scale areas and present a novel approach for the automatic reconstruction of cities from remote sensor data. The goal in this work is to automatically create lightweight, watertight polygonal 3D models from LiDAR data(Light Detection and Ranging) captured by an airborne scanner. This is achieved in three steps: preprocessing, segmentation and modeling, as shown in Figure 1.
Our main technical contributions in this paper are: (i) a novel, robust, automatic segmentation technique based on the statistical analysis of the geometric properties of the data, which makes no particular assumptions about the input data, thus having no data dependencies, and (ii) an efficient and automatic modeling pipeline for the reconstruction of large-scale areas containing several thousands of buildings.
We have extensively tested the proposed approach with several city-size datasets including downtown Baltimore, downtown Denver, the city of Atlanta, downtown Oakland, and we present and evaluate the experimental results.

Automatic Creation of Massive Virtual Cities

Charalambos Poullis, Suya You
Conference Papers IEEE Virtual Reality

Abstract

This research effort focuses on the historically-difficult problem of creating large-scale (city size) scene models from sensor data, including rapid extraction and modeling of geometry models.
The solution to this problem is sought in the development of a novel modeling system with a fully automatic technique for the extraction of polygonal 3D models from LiDAR (Light Detection And Ranging) data. The result is an accurate 3D model representation of the real-world as shown in Figure 1. We present and evaluate experimental results of our approach for the automatic reconstruction of large U.S. cities.

Photorealistic Large-scale Urban City Model Reconstruction

Charalambos Poullis, Suya You
Journal Paper IEEE Transactions on Visualization and Computer Graphics

Abstract

The rapid and efficient creation of virtual environments has become a crucial part of virtual reality applications. In particular, civil and defense applications often require and employ detailed models of operations areas for training, simulations of different scenarios, planning for natural or man-made events, monitoring, surveillance, games and films. A realistic representation of the large-scale environments is therefore imperative for the success of such applications since it increases the immersive experience of its users and helps reduce the difference between physical and virtual reality. However, the task of creating such large-scale virtual environments still remains a time-consuming and manual work.
In this work we propose a novel method for the rapid reconstruction of photorealistic large-scale virtual environments. First, a novel, extendible, parameterized geometric primitive is presented for the automatic building identification and reconstruction of building structures. In addition, buildings with complex roofs containing complex linear and non-linear surfaces are reconstructed interactively using a linear polygonal and a nonlinear primitive, respectively. Secondly, we present a rendering pipeline for the composition of photorealistic textures which unlike existing techniques it can recover missing or occluded texture information by integrating multiple information captured from different optical sensors (ground, aerial and satellite).

Rapid Creation of Large-scale Photorealistic Virtual Environments

Charalambos Poullis, Suya You
Conference Papers IEEE Virtual Reality

Abstract

The rapid and efficient creation of virtual environments has become a crucial part of virtual reality applications. In particular, civil and defense applications often require and employ detailed models of operations areas for training, simulations of different scenarios, planning for natural or man-made events, monitoring, surveillance, games and films. A realistic representation of the large-scale environments is therefore imperative for the success of such applications since it increases the immersive experience of its users and helps reduce the difference between physical and virtual reality. However, the task of creating such large-scale virtual environments still remains a time-consuming and manual work.
In this work we propose a novel method for the rapid reconstruction of photorealistic large-scale virtual environments. First, a novel parameterized geometric primitive is presented for the automatic building detection, identification and reconstruction of building structures. In addition, buildings with complex roofs containing non-linear surfaces are reconstructed interactively using a nonlinear primitive. Secondly, we present a rendering pipeline for the composition of photorealistic textures which unlike existing techniques it can recover missing or occluded texture information by integrating multiple information captured from different optical sensors (ground, aerial and satellite).

A Vision-based System for Automatic Detection and Extraction of Road Networks

Charalambos Poullis, Suya You, Ulrich Neumann
Conference Papers IEEE Workshop on Applications of Computer Vision

Abstract

In this paper we present a novel vision-based system for automatic detection and extraction of complex road networks from various sensor resources such as aerial photographs, satellite images, and LiDAR. Uniquely, the proposed system is an integrated solution that merges the power of perceptual grouping theory(gabor filtering, tensor voting) and optimized segmentation techniques(global optimization using graph-cuts) into a unified framework to address the challenging problems of geospatial feature detection and classification.
Firstly, the local presicion of the gabor filters is combined with the global context of the tensor voting to produce accurate classification of the geospatial features. In addition, the tensorial representation used for the encoding of the data eliminates the need for any thresholds, therefore removing any data dependencies.
Secondly, a novel orientation-based segmentation is presented which incorporates the classification of the perceptual grouping, and results in segmentations with better defined boundaries and continuous linear segments.
Finally, a set of gaussian-based filters are applied to automatically extract centerline information (magnitude, width and orientation). This information is then used for creating road segments and then transforming them to their polygonal representations.

Linear Feature Extraction Using Perceptual Grouping And Graph-Cuts

Charalambos Poullis, Suya You, Ulrich Neumann
Conference Papers ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems

Abstract

In this paper we present a novel system for the detection and extraction of road map information from high-resolution satellite imagery.
Uniquely, the proposed system is an integrated solution that merges the power of perceptual grouping theory (gabor filtering, tensor voting) and segmentation (graph-cuts) into a unified framework to address the problems of road feature detection and classification. Local orientation information is derived using a bank of gabor filters and is refined using tensor voting. A segmentation method based on global optimization by graph-cuts is developed for segmenting foreground(road pixels) and background objects while preserving oriented boundaries. Road centerlines are detected using pairs of gaussian-based filters and road network vector maps are finally extracted using a tracking algorithm.
The proposed system works with a single or multiple images, and any available elevation information. User interaction is limited and is performed at the begining of the system execution. User intervention is allowed at any stage of the process to refine or edit the automatically generated results.

Generating High-Resolution Textures For 3D Virtual Environments using View-Independent Texture Mapping

Charalambos Poullis, Suya You, Ulrich Neumann
Conference Papers IEEE International Conference on Multimedia and Expo

Abstract

Image based modeling and rendering techniques have become increasingly popular for creating and visualizing 3D models from a set of images. Typically, these techniques depend on view-dependent texture mapping to render the textured 3D models in which the texture of novel views is synthesized at runtime according to different view-points. This is computationaly expensive and limits their application in domains where efficient computations are required, such as games and virtual reality. In this paper we present an offline technique for creating view-independent texture atlases for 3D models, given a set of registered images. The best texture map resolution is computed by considering the areas of the projected polygons in the images. Texture maps are generated by a weighted composition of all available image information in the scene.Assuming that all surfaces of the model are exhibiting Lambertian reflectance properties, ray-tracing is then employed, for creating the view-independent texture maps. Finally, all the generated texture maps are packed into texture atlases. The result is a 3D model with an associated view independent texture atlas which can be used efficiently in any application without any knowledge of camera pose information.

"The Parthenon"

Paul Debevec, Chris Tchou, Andrew Gardner, Tim Hawkins, Charalambos (Charis) Poullis, Jessi Stumpfel, Andrew Jones, Nathaniel Yun, Per Einarsson, Therese Lundgren, Marcos Fajardo, Philippe Martinez
Other (Short Film) ACM SIGGRAPH Electronic Theater

Abstract

"The Parthenon" is a short computer animation which visually reunites the Parthenon and its sculptural decorations, separated since the early 1800s. The film used combinations of time-of-flight laser scanning, structured light scanning, photometric stereo, inverse global illumination, photogrammetric modeling, image-based rendering, BRDF measurement, and Monte-Carlo global illumination in order to create the twenty-some shots used in the film.

Estimating Surface Reflectance Properties of a Complex Scene under Captured Natural Illumination

Paul Debevec, Chris Tchou, Andrew Gardner, Tim Hawkins, Charalambos (Charis) Poullis, Jessi Stumpfel, Andrew Jones, Nathaniel Yun, Per Einarsson, Therese Lundgren, Marcos Fajardo, Philippe Martinez
Journal Paper ACM Transactions on Graphics

Abstract

We present a process for estimating spatially-varying surface reflectance of a complex scene observed under natural illumination conditions. The process uses a laser-scanned model of the scene’s geometry, a set of digital images viewing the scene’s surfaces under a variety of natural illumination conditions, and a set of corresponding measurements of the scene’s incident illumination in each photograph. The process then employs an iterative inverse global illumination technique to compute surface colors for the scene which, when rendered under the recorded illumination conditions, best reproduce the scene’s appearance in the photographs. In our process we measure BRDFs of representative surfaces in the scene to better model the non-Lambertian surface reflectance. Our process uses a novel lighting measurement apparatus to record the full dynamic range of both sunlit and cloudy natural illumination conditions. We employ Monte-Carlo global illumination, multiresolution geometry, and a texture atlas system to perform inverse global illumination on the scene. The result is a lighting-independent model of the scene that can be re-illuminated under any form of lighting. We demonstrate the process on a real-world archaeological site, showing that the technique can produce novel illumination renderings consistent with real photographs as well as reflectance properties that are consistent with ground-truth reflectance measurements.

Current Teaching

  • Fall 2014

    MGA318 Interactive Multimedia II

    Cyprus University of Technology

    Course website

  • Fall 2014

    MGA410 Applied Multimedia

    Cyprus University of Technology

    Course website

Teaching History

  • Spring 2014

    MGA243 Multimedia Programming

    Cyprus University of Technology

    Course website

  • Spring 2014

    MGA515 Creative Technologies

    Cyprus University of Technology

    Course website

  • Fall 2013

    MGA310 3D Modeling and Animation I

    Cyprus University of Technology

    Course website

  • Fall 2013

    MGA410 Applied Multimedia

    Cyprus University of Technology

    Course website

  • Spring 2013

    MGA343 Multimedia Programing

    Cyprus University of Technology

    Course website

  • Spring 2013

    MGA515 Creative Technologies

    Cyprus University of Technology

    Course website

  • Fall 2012

    MGA310 3D Modeling and Animation I

    Cyprus University of Technology

    Course website

  • Fall 2012

    MGA410 Applied Multimedia

    Cyprus University of Technology

    Course website

  • Spring 2012

    MGA315 3D Modeling and Animation II

    Cyprus University of Technology

    Course website

  • Spring 2012

    MGA343 Multimedia Programing

    Cyprus University of Technology

    Course website

  • Spring 2012

    MGA515 Interactive Multimedia II

    Cyprus University of Technology

    Course website

  • Fall 2012

    MGA410 Applied Multimedia

    Cyprus University of Technology

    Course website

  • Spring 2011

    MGA315 3D Modeling and Animation II

    Cyprus University of Technology

    Course website

  • Spring 2011

    MGA416 Creative Technologies

    Cyprus University of Technology

    Course website

  • Fall 2010

    EPL032 Problem Solving and Program Design

    University of Cyprus

    Course website

  • Fall 2010

    EPL447 Computer Vision

    University of Cyprus

    Course website

  • Fall 2009

    EPL003 Computer Science and Computational Systems

    University of Cyprus

    Course website

  • Fall 2009

    EPL233 Object-Oriented Programming

    University of Cyprus

    Course website

Current Supervision

  • Coming soon

Supervision History

  • Fall 2013

    Towards a More Effective Way of Presenting Virtual Reality Museums Exhibits

    Cyprus University of Technology

    Graduate student researcher: Constantinos Terlikkas

  • Fall 2013

    Towards Effective Immersive Visualizations for the Training and Enhancement of Social Skills for Children with Autism

    Cyprus University of Technology

    Graduate student researcher: Skevi Matsentidou

  • Fall 2013

    Visualizing and Assessing Scenarios in Marine Archeology in a VR CAVE environment

    Cyprus University of Technology

    Graduate student researcher: Irene Katsouri

  • Fall 2012

    Game Design and Development on Android Mobile Devices

    Cyprus University of Technology

    Graduate student researcher: Diomidis Papadiomidous

  • Fall 2012

    Alternative Projection Mapping for Live Performances

    Cyprus University of Technology

    Graduate student researcher: Kyriakos Herakleous

  • Fall 2012

    Design and Development of an Educational Game on Apple Ipad

    Cyprus University of Technology

    Graduate student researcher: Maria Papadouri

  • Fall 2012

    Design and Development of Social-networking Website

    Cyprus University of Technology

    Graduate student researcher: Andri Parpa

  • Spring 2012

    Design and Development of a Game with Blender

    Cyprus University of Technology

    Undergraduate student researcher: Kriton Florides

  • Spring 2012

    Interactive Multimedia Application for Advertising

    Cyprus University of Technology

    Undergraduate student researcher: Desi Mincheva

  • Spring 2012

    Team "Sweet Dreams" - Imagine Cup 2012 by Microsoft®

    Cyprus University of Technology

    The Imagine Cup is a worldwide student technology competition aimed at helping solve some of the biggest problems facing the world today with innovative technology solutions.

    The local competition in the Game Design category took place on the 30th April 2012, in Nicosia, Cyprus. The local competition was hosted at the Department of Computer Science at Frederick University and coordinated by Microsoft® Cyprus.

    The team I am supervising was the winner of the local competition with their game Sweet Dreams.

    The team consists of Kyriakos Herakleous (M.Sc. student), Maria Christofi (B.A. student), Kritonas Florides (B.A. student)

    All members are students of the Department of Multimedia and Graphic Arts, of the Cyprus University of Technology.

    You can play the game online: here

    Instructions

    Trailer

    Gameplay video

  • Spring 2011

    Team "iDoc" - Imagine Cup 2011 by Microsoft®

    University of Cyprus

    The Imagine Cup is a worldwide student technology competition aimed at helping solve some of the biggest problems facing the world today with innovative technology solutions.

    The first part of the competition is local to Cyprus and took place on 15th April 2011. The local competition was hosted at the Department of Computer Science at the University of Cyprus and coordinated by Microsoft® Cyprus.

    The team I am supervising was the winner of the local competition and will be representing Cyprus in the second part of the competition; the Imagine Cup World Finals 2011, to be held in New York in July 2011. The innovative software solution is iDoc.

    News articles: 1, 2, 3, 4, 5, 6, 7, 8.

    All members are students of the Department of Computer Science, University of Cyprus.

  • Spring 2011

    3D Object Scanning using Active and Passive Sensor Technologies

    University of Cyprus

    Undergraduate student researcher: Alexia Kolosova

  • Spring 2011

    Mixed Reality Story Telling: Greek Mythology (Feature-less tracking)

    University of Cyprus

    Undergraduate student researcher: Kyriakos Herakleous

  • Spring 2011

    Development of a Game with Blender

    Cyprus University of Technology

    Undergraduate student researcher: Mikaella Papagianni

  • Spring 2011

    Mixed Reality Story Telling: Greek Mythology (Feature-less tracking)

    Cyprus University of Technology

    Undergraduate student researcher: Smaragda Christodoulou

Under Active Development

  • VRCAVE v1.0

    Project for Multi-screen Setup for Unity3D

    Project: VR CAVE - www.vrcave.com.cy

    Coming soon

  • 3DUW v3.1

    Structured-Light Scanning Software

    Project: 3D UNDERWORLD - www.3dunderworld.org

    Latest stable version: v3.1

    Download from Github

Other

At My Office

My office is located on the 2nd floor of the Iacovides Building. The address is:

Iacovides Building, 2nd floor
94 Anexartisias Street,
3036 Limassol,
Cyprus

At My Lab

The ICT lab is located in the basement(-1) of the Micrologic Building. The address is:

Basement Floor (-1),
Micrologic Building,
31 Le Corbusier Street,
3075 Limassol,
Cyprus