Search Results

Now showing 1 - 10 of 25
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    Virtual Dance Museum: the Case of Greek/Cypriot Folk Dancing
    (The Eurographics Association, 2021) Aristidou, Andreas; Andreou, Nefeli; Charalambous, Loukas; Yiannakidis, Anastasios; Chrysanthou, Yiorgos; Hulusic, Vedad and Chalmers, Alan
    In this paper, we have designed and developed a virtual dance museum to provide the technological tools that allow for widely educating the public, most specifically the youngest generations, about the story, costumes, music, and history of our dances. The holistic documentation of our intangible cultural heritage creations is a critical necessity for the preservation and the continuity of our identity as Europeans. In that direction, we have employed a specially designed relational database schema that holistically structures the information within the database, and is ideal for archiving, presenting, further analyzing, and re-using dance motion data. Data have been retargeted to a virtual character, dressed with traditional uniform and simulated to achieve realism. The users can view and interact with the archived data using advanced 3D character visualization in three ways: via an online 3D virtual environment; in virtual reality using headset; and in augmented reality, where the 3D characters can co-inhabit the real world. Our museum is publicly accessible, and also enables motion data reusability, facilitating dance learning applications through gamification.
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    A Data-Driven Framework for Visual Crowd Analysis
    (The Eurographics Association and John Wiley and Sons Ltd., 2014) Charalambous, Panayiotis; Karamouzas, Ioannis; Guy, Stephen J.; Chrysanthou, Yiorgos; J. Keyser, Y. J. Kim, and P. Wonka
    We present a novel approach for analyzing the quality of multi-agent crowd simulation algorithms. Our approach is data-driven, taking as input a set of user-defined metrics and reference training data, either synthetic or from video footage of real crowds. Given a simulation, we formulate the crowd analysis problem as an anomaly detection problem and exploit state-of-the-art outlier detection algorithms to address it. To that end, we introduce a new framework for the visual analysis of crowd simulations. Our framework allows us to capture potentially erroneous behaviors on a per-agent basis either by automatically detecting outliers based on individual evaluation metrics or by accounting for multiple evaluation criteria in a principled fashion using Principle Component Analysis and the notion of Pareto Optimality. We discuss optimizations necessary to allow real-time performance on large datasets and demonstrate the applicability of our framework through the analysis of simulations created by several widely-used methods, including a simulation from a commercial game.
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    Emotion Control of Unstructured Dance Movements
    (ACM, 2017) Aristidou, Andreas; Zeng, Qiong; Stavrakis, Efstathios; Yin, KangKang; Cohen-Or, Daniel; Chrysanthou, Yiorgos; Chen, Baoquan; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
    Motion capture technology has enabled the acquisition of high quality human motions for animating digital characters with extremely high fidelity. However, despite all the advances in motion editing and synthesis, it remains an open problem to modify pre-captured motions that are highly expressive, such as contemporary dances, for stylization and emotionalization. In this work, we present a novel approach for stylizing such motions by using emotion coordinates de ned by the Russell's Circumplex Model (RCM).We extract and analyze a large set of body and motion features, based on the Laban Movement Analysis (LMA), and choose the e ective and consistent features for characterizing emotions of motions. These features provide a mechanism not only for deriving the emotion coordinates of a newly input motion, but also for stylizing the motion to express a di erent emotion without having to reference the training data. Such decoupling of the training data and new input motions eliminates the necessity of manual processing and motion registration. We implement the two-way mapping between the motion features and emotion coordinates through Radial Basis Function (RBF) regression and interpolation, which can stylize freestyle highly dynamic dance movements at interactive rates. Our results and user studies demonstrate the e ectiveness of the stylization framework with a variety of dance movements exhibiting a diverse set of emotions.
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    Automatic Environment Map Registration
    (The Eurographics Association, 2019) Larvy, Ulysse; Loscos, Céline; Chrysanthou, Yiorgos; Cignoni, Paolo and Miguel, Eder
    In this paper, a method to automatically register an environment map (EM) around a local scene is presented. In the literature, this step is most of the time manually processed by a user. However, it is an essential step when lighting and/or background coherence is needed. We present a method to find the coherent spatial organization between a main light source present in the EM and a couple object/shadow in a local scene. We automatically recover the EM orientation which corresponds to the local scene illumination. We proceed to a 3D representation of the scene using the EM mapped on a hemisphere as a background scene, a simplified geometry description of the reference object and its shadow outline. As a first step, we compute a projection of the main object shadow to compare it against the real acquired shadow. In a second step, we minimize a metric based on Euclidean Distance Transform (EDT), to compare both shadows and to recover the EM orientation. We demonstrate that we can automatically find rotation and scaling parameters that position in a coherent manner the background around a local scene.
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    High Dynamic Range Display of Authentically Illuminated Byzantine Art from Cyprus
    (The Eurographics Association, 2007) Zanyi, Eva; Chrysanthou, Yiorgos; Bashford-Rogers, Tom; Chalmers, Alan; D. Arnold and F. Niccolucci and A. Chalmers
    High-fidelity computer reconstructions of cultural heritage sites attempt to create a faithful representation of the past physical environment. This includes modeling the scene to high precision, and accurately simulating the distribution of authentic light energy within the scene. This does not, however, ensure that the displayed image will have a high fidelity visual appearance due to the limited dynamic range of typical computer displays. Such displays only have a range of about two orders of magnitude between minimum and maximum luminance. A welldesigned cathode ray tube (CRT) monitor may do slightly better than this in a darkened room, but the maximum display luminance is only around 100 cd/m2, which does not even begin to approach natural daylight levels of approximately 105 cd/m2. Furthermore, their inability to display 'true black' means that standard displays also struggle to show low-light images accurately. In this paper we compare images of computer reconstructions of Byzantine art from Cyprus illuminated with simulated modern lighting and the candle light which was present in Byzantine times on both a traditional and a novel High Dynamic Range display.
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    Crowds by Example
    (The Eurographics Association and Blackwell Publishing Ltd, 2007) Lerner, Alon; Chrysanthou, Yiorgos; Lischinski, Dani
    We present an example-based crowd simulation technique. Most crowd simulation techniques assume that the behavior exhibited by each person in the crowd can be defined by a restricted set of rules. This assumption limits the behavioral complexity of the simulated agents. By learning from real-world examples, our autonomous agents display complex natural behaviors that are often missing in crowd simulations. Examples are created from tracked video segments of real pedestrian crowds. During a simulation, autonomous agents search for examples that closely match the situation that they are facing. Trajectories taken by real people in similar situations, are copied to the simulated agents, resulting in seemingly natural behaviors.
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    Automatic High Level Avatar Guidance Based on Affordance of Movement
    (Eurographics Association, 2003) Michael, Despina; Chrysanthou, Yiorgos
    As virtual cities become ever more common and more extensive, the need to populate them with virtual pedestrians grows. One of the problems to be resolved for the virtual population is the behaviour simulation. Currently specifying the behaviour requires a lot of laborious work. In this paper we propose a method for automatically deriving the high level behaviour of the avatars. We introduce to the Graphics community a new method adapted from ideas recently presented in the Architecture literature. In this method, the general avatar movements are derived from an analysis of the structure of the architectural model. The analysis tries to encode Gibsons 7 principle of affordance, interpreted here as: pedestrians are more attracted towards directions with greater available walkable surface. We have implemented and tested the idea in a 2x2 km2 model of the city of Nicosia. Initial results indicate that the method, although simple, can automatically and efficiently populate the model with realistic results.
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    Virtual Instrument Performances (VIP): A Comprehensive Review
    (The Eurographics Association and John Wiley & Sons Ltd., 2024) Kyriakou, Theodoros; Alvarez de la Campa Crespo, Merce; Panayiotou, Andreas; Chrysanthou, Yiorgos; Charalambous, Panayiotis; Aristidou, Andreas; Aristidou, Andreas; Macdonnell, Rachel
    Driven by recent advancements in Extended Reality (XR), the hype around the Metaverse, and real-time computer graphics, the transformation of the performing arts, particularly in digitizing and visualizing musical experiences, is an ever-evolving landscape. This transformation offers significant potential in promoting inclusivity, fostering creativity, and enabling live performances in diverse settings. However, despite its immense potential, the field of Virtual Instrument Performances (VIP) has remained relatively unexplored due to numerous challenges. These challenges arise from the complex and multi-modal nature of musical instrument performances, the need for high precision motion capture under occlusions including the intricate interactions between a musician's body and fingers with instruments, the precise synchronization and seamless integration of various sensory modalities, accommodating variations in musicians' playing styles, facial expressions, and addressing instrumentspecific nuances. This comprehensive survey delves into the intersection of technology, innovation, and artistic expression in the domain of virtual instrument performances. It explores musical performance multi-modal databases and investigates a wide range of data acquisition methods, encompassing diverse motion capture techniques, facial expression recording, and various approaches for capturing audio and MIDI data (Musical Instrument Digital Interface). The survey also explores Music Information Retrieval (MIR) tasks, with a particular emphasis on the Musical Performance Analysis (MPA) field, and offers an overview of various works in the realm of Musical Instrument Performance Synthesis (MIPS), encompassing recent advancements in generative models. The ultimate aim of this survey is to unveil the technological limitations, initiate a dialogue about the current challenges, and propose promising avenues for future research at the intersection of technology and the arts.
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    Authoring Virtual Crowds: A Survey
    (The Eurographics Association and John Wiley & Sons Ltd., 2022) Lemonari, Marilena; Blanco, Rafael; Charalambous, Panayiotis; Pelechano, Nuria; Avraamides, Marios; Pettré, Julien; Chrysanthou, Yiorgos; Meneveaux, Daniel; Patanè, Giuseppe
    Recent advancements in crowd simulation unravel a wide range of functionalities for virtual agents, delivering highly-realistic, natural virtual crowds. Such systems are of particular importance to a variety of applications in fields such as: entertainment (e.g., movies, computer games); architectural and urban planning; and simulations for sports and training. However, providing their capabilities to untrained users necessitates the development of authoring frameworks. Authoring virtual crowds is a complex and multi-level task, varying from assuming control and assisting users to realise their creative intents, to delivering intuitive and easy to use interfaces, facilitating such control. In this paper, we present a categorisation of the authorable crowd simulation components, ranging from high-level behaviours and path-planning to local movements, as well as animation and visualisation. We provide a review of the most relevant methods in each area, emphasising the amount and nature of influence that the users have over the final result. Moreover, we discuss the currently available authoring tools (e.g., graphical user interfaces, drag-and-drop), identifying the trends of early and recent work. Finally, we suggest promising directions for future research that mainly stem from the rise of learning-based methods, and the need for a unified authoring framework.
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    42nd EUROGRAPHICS General Assembly  
    (2020-11-20) Chrysanthou, Yiorgos