Andreas Aristidou

Andreas Aristidou
University of Cyprus · Department of Computer Science

PhD

About

48
Publications
91,059
Reads
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1,342
Citations
Introduction
Andreas Aristidou is an Assistant Professor at the University of Cyprus, and a Research Fellow at the CYENS Centre of Excellence with special interest in computer graphics and character animation. His main interests are focused on 3D motion analysis, classification, and synthesis, and involve motion capture, inverse kinematics, deep convolutional and reinforcement learning, intangible cultural heritage, and applications of conformal geometric algebra in graphics.
Additional affiliations
August 2019 - present
University of Cyprus
Position
  • Professor (Assistant)
Description
  • Assistant Professor at the University of Cyprus, and Adjunct Senior Researcher at the RISE research center with special interest in computer graphics and character animation.
June 2018 - July 2019
University of Cyprus
Position
  • PostDoc Position
Description
  • Senior Post-Doctoral Fellow at the Department of Computer Science. Project Manager of the Safeguarding the Cultural HEritage of Dance through Augmented Reality.
February 2016 - June 2018
Interdisciplinary Center Herzliya
Position
  • PostDoc Position
Education
April 2007 - April 2011
University of Cambridge
Field of study
  • Information Engineering
October 2005 - September 2006
King's College London
Field of study
  • Mobile and Personal Communications
September 2001 - September 2005
National and Kapodistrian University of Athens
Field of study
  • Informatics and Telecommunications

Publications

Publications (48)
Article
Full-text available
Inverse Kinematics is defined as the problem of determining a set of appropriate joint configurations for which the end effectors move to desired positions as smoothly, rapidly, and as accurately as possible. However, many of the currently available methods suffer from high computational cost and production of unrealistic poses. In this paper, a no...
Article
Full-text available
The increasing availability of large motion databases, in addition to advancements in motion synthesis, has made motion indexing and classification essential for better motion composition. However, in order to achieve good connectivity in motion graphs, it is important to understand human behaviour; human movement though is complex and difficult to...
Article
Full-text available
Inverse kinematics (IK) is the use of kinematic equations to determine the joint parameters of a manipulator so that the end effector moves to a desired position; IK can be applied in many areas, including robotics, engineering, computer graphics and video games. In this survey, we present a comprehensive review of the IK problem and the solutions...
Preprint
Full-text available
We introduce MotioNet, a deep neural network that directly reconstructs the motion of a 3D human skeleton from monocular video.While previous methods rely on either rigging or inverse kinematics (IK) to associate a consistent skeleton with temporally coherent joint rotations, our method is the first data-driven approach that directly outputs a kine...
Article
Full-text available
Many analysis tasks for human motion rely on high-level similarity between sequences of motions, that are not an exact matches in joint angles, timing, or ordering of actions. Even the same movements performed by the same person can vary in duration and speed. Similar motions are characterized by similar sets of actions that appear frequently. In t...
Conference Paper
Full-text available
With the technological advancements and the widespread adoption of the internet, the physical library has lost its role as the main resource of information. As the Metaverse is becoming more and more apparent, a revolutionary change is expected in how we understand social relationships and consequently, education. It is therefore necessary for libr...
Article
Full-text available
In this paper we design and develop a 3D virtual museum with holistic metadata documentation and a variety of reptile behaviors and movements. First, we reconstruct the reptiles mesh in high resolution, and then create its rigged/skinned digital counterpart. We acquire the movement of two subjects using an optical motion capture system, acceleromet...
Article
Full-text available
Professional dancing is characterized by high impulsiveness, elegance, and aesthetic beauty. In order to reach the desired professionalism, it requires years of long and exhausting practice, good physical condition, musicality, but also, a good understanding of the choreography. Capturing dance motions and transferring them into digital avatars is...
Conference Paper
Full-text available
Folk dancing is a key aspect of intangible cultural heritage that often reflects the socio-cultural and political influences prevailing in different periods and nations; each dance produces a meaning, a story with the help of music, costumes and dance moves. It has been transmitted from generation to generation, and to different countries, mainly d...
Article
Full-text available
Synthesizing human motion with a global structure, such as a choreography, is a challenging task. Existing methods tend to concentrate on local smooth pose transitions and neglect the global context or the theme of the motion. In this work, we present a music-driven motion synthesis framework that generates long-term sequences of human motions whic...
Preprint
Full-text available
Data-driven character animation techniques rely on the existence of a properly established model of motion, capable of describing its rich context. However, commonly used motion representations often fail to accurately encode the full articulation of motion, or present artifacts. In this work, we address the fundamental problem of finding a robust...
Preprint
Full-text available
Synthesizing human motion with a global structure, such as a choreography, is a challenging task. Existing methods tend to concentrate on local smooth pose transitions and neglect the global context or the theme of the motion. In this work, we present a music-driven motion synthesis framework that generates long-term sequences of human motions whic...
Conference Paper
Full-text available
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...
Article
We introduce MotioNet, a deep neural network that directly reconstructs the motion of a 3D human skeleton from monocular video. While previous methods rely on either rigging or inverse kinematics (IK) to associate a consistent skeleton with temporally coherent joint rotations, our method is the first data-driven approach that directly outputs a kin...
Conference Paper
Full-text available
Child characters are commonly seen in leading roles in top-selling video games. Previous studies have shown that child motions are perceptually and stylistically different from those of adults. Creating motion for these characters by motion capturing children is uniquely challenging because of confusion, lack of patience and regulations. Retargetin...
Article
Full-text available
Learning couple dance such as salsa is challenging as it requires to understand and assimilate all the dance skills (guidance, rhythm, style) correctly. Salsa is traditionally learned by attending a dancing class with a teacher and practice with a partner, the difficulty to access such classes though, and the variability of dance environment can im...
Article
Full-text available
Folk dances often reflect the socio-cultural influences prevailing in different periods and nations; each dance produces a meaning, a story with the help of music, costumes and dance moves. However, dances have no borders; they have been transmitted from generation to generation, along different countries, mainly due to movements of people carrying...
Article
Full-text available
Synthesizing human motions from existing motion capture data is the approach of choice in most applications requiring high- quality visual results. Usually to synthesize motion, short motion segments are concatenated into longer sequences by finding transitions at points where character poses are similar. If similarity is only a measure of posture...
Article
Full-text available
Motion capture sequences may contain erroneous data, especially when the motion is complex or performers are interacting closely and occlusions are frequent. Common practice is to have specialists visually detect the abnormalities and fix them manually. In this paper, we present a method to automatically analyze and fix motion capture sequences by...
Article
Full-text available
Articulated hand tracking systems have been commonly used in virtual reality applications, including systems with human–computer interaction or interaction with game consoles; hand pose estimation has various other applications comprising sign language recognition and animation synthesis. The advanced technological achievements in motion capture ov...
Conference Paper
Full-text available
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 e...
Article
Full-text available
Understanding emotional human behavior in its multimodal and continuous aspect is necessary for studying human machine interaction and creating constituent social agents. As a first step, we propose a system for continuous emotional behavior recognition expressed by people during communication based on their gesture and their whole body dynamical m...
Article
Full-text available
Forward and Backward Reaching Inverse Kinematics (FABRIK) is a recent iterative inverse kinematics solver that became very popular because of its simplicity, convergence speed and control performance, especially in models with multiple end effectors. In this paper, we extend and/or adjust FABRIK to be used in problems with leaf joints and closed-lo...
Conference Paper
Full-text available
Η τεχνολογία motion capture (mocap) είναι μια αποτελεσματική μέθοδος τρισδιάστατης (3Δ) ψηφιακής καταγραφής κίνησης, και η χρήση της αυξάνεται ολοένα και περισσότερο στον τομέα της διατήρησης και διάδοσης της Άυλης Πολιτιστικής Κληρονομιάς (ΑΠΚ). Αν και τα δεδομένα που καταγράφονται μπορούν από τεχνικής άποψης να είναι πολύ υψηλής ποιότητας, στην π...
Article
Full-text available
Motion capture (mocap) technology is an efficient method for digitizing art performances, and is becoming increasingly popular in the preservation and dissemination of dance performances. Although technically the captured data can be of very high quality, dancing allows stylistic variations and improvisations that cannot be easily identified. The m...
Conference Paper
Full-text available
Over the last few years, recent advances in user interface and mobile computing, introduce the ability to create new experiences that enhance the way we acquire, interact and display information within the world that surrounds us with virtual characters [1], [2]. Virtual Reality (VR) is a 3D computer simulated environment that gives the user the ex...
Conference Paper
Full-text available
Motion capture (mocap) technology is an efficient method for digitizing art-performances, and it is becoming a popular method for the preservation and dissemination of dances. However, stylistic variations of human motion are difficult to measure and cannot be directly extracted from the motion capture data itself. In this work, we present a framew...
Conference Paper
Full-text available
Motion capture techniques are becoming a popular method for digitizing folk dances for preservation and dis-semination. Although technically the captured data can be of very high quality, folk dancing, in contrast to choreographed performances, allow for stylistic variations and improvisations that cannot be easily captured by the data themselves....
Article
Full-text available
Cultural Heritage Cyprus has a long and rich history of dance tradition which unfortunately, year after year, tends to be forgotten; thus, it is our duty to help documenting and disseminating our dance heritage to the younger generations. In this work, we aim to preserve the Cypriot folk dance heritage, creating a state-of-the-art publicly accessib...
Conference Paper
Full-text available
There has been an increasing use of pre-recorded motion capture data for animating virtual characters and synthesising different actions; it is although a necessity to establish a resultful method for indexing, classifying and retrieving motion. In this paper, we propose a method that can automatically extract motion qualities from dance performanc...
Conference Paper
Full-text available
Recently, there has been an increasing use of pre-recorded motion capture data, making motion indexing and classification essential for animating virtual characters and synthesising different actions. In this paper, we use a variety of features that encode characteristics of motion using the Body, Effort, Shape and Space components of Laban Movemen...
Conference Paper
Full-text available
Exergames do not have the capacity to detect whether the players are really enjoying the game-play. The games are not intelligent enough to detect significant emotional states and adapt accordingly in order to offer a better user experience for the players. We pro- pose a set of body motion features, based on the Effort component of Laban Movement...
Technical Report
Full-text available
Optical motion capture systems suffer from marker occlusions resulting in loss of useful information. This technical report addresses the problem of real-time joint localisation of human skeletons in the presence of such missing data; at least three markers are placed at strategic positions on each limb segment. The data is assumed to be labelled 3...
Article
Full-text available
Optical motion capture systems suffer from marker occlusions resulting in loss of useful information. This paper addresses the problem of real-time joint localisation of legged skeletons in the presence of such missing data. The data is assumed to be labelled 3d marker positions from a motion capture system. An integrated framework is presented whi...
Conference Paper
Full-text available
In this article an initiative to preserve the Cypriot folk dance heritage is reported. The project aims to create a publicly accessible digital archive of folk dances that does not only include video recordings, commonly used to document dance performances. In addition to rare video material held by local cultural institutions, state-of-the-art mot...
Chapter
Full-text available
This paper describes a novel iterative Inverse Kinematics (IK) solver, FABRIK, that is implemented using Conformal Geometric Algebra (CGA). FABRIK uses a forward and backward iterative approach, finding each joint position via locating a point on a line. We use the IK of a human hand as an example of implementation where a constrained version of FA...
Thesis
Full-text available
This thesis focuses on the problem of determining appropriate skeletal configurations for which a virtual animated character moves to desired positions as smoothly, rapidly, and as accurately as possible. During the last decades, several methods and techniques, sophisticated or heuristic, have been presented to produce smooth and natural solutions...
Article
Full-text available
Articulated hand tracking systems have been commonly used in virtual reality applications, including systems with human-computer interaction or interaction with game consoles. However, building an effective real-time hand pose tracker remains challenging. In this paper, we present a simple and efficient methodology for tracking and reconstructing 3...
Conference Paper
Full-text available
Articulated hand tracking systems have been commonly used in virtual reality applications, including systems with human-computer interaction or interaction with game consoles. However, building an effective real-time hand pose tracker remains challenging. In this paper, we present a simple and efficient methodology for tracking and reconstructing 3...
Technical Report
Full-text available
Inverse Kinematics (IK) is defined as the problem of determining a set of appropriate joint configurations for which the end effectors move to desired positions as smoothly, rapidly, and as accurately as possible. During the last decades, several methods and techniques, sophisticated or heuristic, have been presented to produce fast and realistic s...
Conference Paper
Full-text available
This paper addresses the problem of real-time location of the joints or centres of rotation (CoR) of human skeletons in the presence of missing data. The data is assumed to be 3d marker positions from a motion capture system. We present an integrated framework which predicts the occluded marker positions using a Kalman filter in combination with in...
Conference Paper
Full-text available
This paper considers the problem of taking marker locations from optical motion capture data to identify and parameterise the underlying human skeleton structure and motion over time. It is concerned with real-time algorithms suitable for use within a visual feedback system. A common problem in motion capture is marker occlusion. Most current metho...
Technical Report
Full-text available
This report considers the problem of using marker locations from optical motion capture data to identify and parameterise the underlying human skeleton structure and motion over time. It is concerned with real-time algorithms suitable for use within a visual feedback system. The algorithms presented require 3 markers on each limb segment and can be...
Thesis
Full-text available
An architecture system and a method for tracking people are presented for sports applications. The system's input is video data from static camera of a stadium and the output is the real world, real-time positions of the players during a sport event. This output can be used for low-bandwidth match play animations for web or wireless display, and fo...
Conference Paper
Full-text available
This work studies the problem of violence detection in audio data, which can be used for automated content rating. We employ some popular frame-level audio features both from the time and frequency domain. Afterwards, several statistics of the calculated feature sequences are fed as input to a Support Vector Machine classifier, which decides about...

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Projects

Projects (3)
Archived project
This project aims at generating a virtual animated character that interacts, in real-time, with a real dancing performer to compose a contemporary dancing show. The proposed research will explore innovative topics with special interest in the area of computer animation, including methods which smoothly combine optical motion capture (mocap) data with kinematic techniques, human figure modelling, a novel methodology for motion classification and partial-body motion synthesis. The system will be adjusted dynamically according to the performers' actions and responses, offering the maximum possible interaction between the natural and virtual performer. Similar techniques can be adapted to the game industry, possibly for military or local law enforcement training simulators or other virtual character animations.
Project
Dance is an integral part of any culture. Through its choreography and costumes dance imparts richness and uniqueness to that culture. Over the last decade, technological developments have been exploited to record, curate, remediate, provide access, preserve and protect tangible CH. However, intangible assets, such as dance, has largely been excluded from this previous work. UNESCO states in its 2003 Convention for the Safeguarding of the Intangible Cultural Heritage (ICH) that ICH is a mainspring of humanity's cultural diversity and its maintenance is a guarantee for continuing creativity. However, modern factors such as globalization and the massive movement of people have diminished the unique culture of many communities, and indeed there is a now a very real risk that many types of ICH may disappear forever. Recent computing advances have enabled the accurate 3D digitization of human motion. Such systems provide a new means for capturing, preserving and subsequently re-creating ICH which goes far beyond traditional written or imaging approaches. However, 3D motion data is expensive to create and maintain, encompassed semantic information is difficult to extract and formulate, and current software tools to search and visualize this data are too complex for most end-users. SCHEDAR will provide novel solutions to the three key challenges of archiving, re-using and re-purposing, and ultimately disseminating ICH motion data. In addition, we will devise a comprehensive set of new guidelines, a framework and software tools for leveraging existing ICH motion databases. Data acquisition will be undertaken holistically; encompassing data related to the performance, the performer, the kind of the dance, the hidden/untold story, etc. Innovative use of state-of-the-art multisensory Augmented Reality technology will enable direct interaction with the dance, providing new experiences and training in traditional dance which is key to ensure this rich culture asset is preserved for future generations.
Archived project
SimPol VR (Synthesis of Dynamic Characters with motion capture data for human figure animation: Educating the police force) is a research project funded by the Cyprus Research Promotion Foundation in the area of Computer Graphics and more specifically in the sub-area of Human Body Animation. The project focuses in investigating the usability and applicability of Virtual Reality in training special forces. It proposes the development of a platform using Computer Graphics techniques (as oppossed to the existing video-based system that is restrictive), for the creation of a 3D Visualisation Tool enriched with tools suitable for the formation and customisation of dynamic scenarios. The proposed platform will be used as a simulator for training purposes by the Cyprus Police Emergency Response Unit. The user of the platform will be able to fully participate, act and interact with the environment. To achieve the above, research will be carried out in the area of Computer Animation for realistic avatar movement as well as the realistic and dynamic change of facial expressions. Smoothing of the surfaces on the avatar models used is another area that will be targeted by this project work. Researchers from Frederick University, the University of Cyprus, P.A. College, the University of Nicosia and abroad will be involved as well as acting trainers from the Cyprus Police Emergency Response Unit.