Skip to main content

Research Repository

Advanced Search

Outputs (53)

A multiscale optimisation algorithm for shape and material reconstruction from a single X-ray image (2024)
Conference Proceeding
Westmacott, H., Ivrissimtzis, I., & Weinzierl, T. (2024). A multiscale optimisation algorithm for shape and material reconstruction from a single X-ray image. In ICIGP '24: Proceedings of the 2024 7th International Conference on Image and Graphics Processing (252-259). https://doi.org/10.1145/3647649.3647690

We produce thickness and bone to soft tissue ratio estimations from a single, 2D medical X-ray image. For this, we simulate the scattering of the rays through a model of the object and embed this simulation into an optimiser which iteratively adjusts... Read More about A multiscale optimisation algorithm for shape and material reconstruction from a single X-ray image.

Anomaly Detection with Transformers in Face Anti-spoofing (2023)
Conference Proceeding
Abduh, L., Omar, L., & Ivrissimtzis, I. (2023). Anomaly Detection with Transformers in Face Anti-spoofing. . https://doi.org/10.24132/JWSCG.2023.10

Transformers are emerging as the new gold standard in various computer vision applications, and have already been used in face anti-spoofing demonstrating competitive performance. In this paper, we propose a network with the ViT transformer and ResNe... Read More about Anomaly Detection with Transformers in Face Anti-spoofing.

Race Bias Analysis of Bona Fide Errors in Face Anti-spoofing (2023)
Conference Proceeding
Abduh, L., & Ivrissimtzis, I. (2023). Race Bias Analysis of Bona Fide Errors in Face Anti-spoofing. In CAIP 2023: Computer Analysis of Images and Patterns (23-32). https://doi.org/10.1007/978-3-031-44240-7_3

The study of bias in Machine Learning is receiving a lot of attention in recent years, however, few only papers deal explicitly with the problem of race bias in face anti-spoofing. In this paper, we present a systematic study of race bias in face ant... Read More about Race Bias Analysis of Bona Fide Errors in Face Anti-spoofing.

Exploring the Potential of Immersive Virtual Environments for Learning American Sign Language (2023)
Conference Proceeding
Wang, J., Ivrissimtzis, I., Li, Z., Zhou, Y., & Shi, L. (2023). Exploring the Potential of Immersive Virtual Environments for Learning American Sign Language. In Responsive and Sustainable Educational Futures: 18th European Conference on Technology Enhanced Learning, EC-TEL 2023, Aveiro, Portugal, September 4–8, 2023, Proceedings (459-474). https://doi.org/10.1007/978-3-031-42682-7_31

Sign languages enable effective communication between deaf and hearing people. Despite years of extensive pedagogical research, learning sign language online comes with a number of difficulties that might be frustrating for some students. Indeed, mos... Read More about Exploring the Potential of Immersive Virtual Environments for Learning American Sign Language.

Developing and Evaluating a Novel Gamified Virtual Learning Environment for ASL (2023)
Conference Proceeding
Wang, J., Ivrissimtzis, I., Li, Z., Zhou, Y., & Shi, L. (2023). Developing and Evaluating a Novel Gamified Virtual Learning Environment for ASL. In Human-Computer Interaction – INTERACT 2023: 19th IFIP TC13 International Conference, York, UK, August 28 – September 1, 2023, Proceedings, Part I (459-468). https://doi.org/10.1007/978-3-031-42280-5_29

The use of sign language is a highly effective way of communicating with individuals who experience hearing loss. Despite extensive research, many learners find traditional methods of learning sign language, such as web-based question-answer methods,... Read More about Developing and Evaluating a Novel Gamified Virtual Learning Environment for ASL.

Bivariate non-uniform subdivision schemes based on L-systems (2023)
Journal Article
Gérot, C., & Ivrissimtzis, I. (2023). Bivariate non-uniform subdivision schemes based on L-systems. Applied Mathematics and Computation, 457, Article 128156. https://doi.org/10.1016/j.amc.2023.128156

L–systems have been used to describe non-uniform, univariate, subdivision schemes, which offer more flexible refinement processes than the uniform schemes, while at the same time are easier to analyse than the geometry driven non-uniform schemes. In... Read More about Bivariate non-uniform subdivision schemes based on L-systems.

User-Defined Hand Gesture Interface to Improve User Experience of Learning American Sign Language (2023)
Book Chapter
Wang, J., Ivrissimtzis, I., Li, Z., Zhou, Y., & Shi, L. (2023). User-Defined Hand Gesture Interface to Improve User Experience of Learning American Sign Language. In C. Frasson, P. Mylonas, & C. Troussas (Eds.), Augmented Intelligence and Intelligent Tutoring Systems: 19th International Conference, ITS 2023, Corfu, Greece, June 2-5, 2023, Proceedings (479-490). Springer Verlag. https://doi.org/10.1007/978-3-031-32883-1_43

Sign language can make possible effective communication between hearing and deaf-mute people. Despite years of extensive pedagogical research, learning sign language remains a formidable task, with the majority of the current systems relying extensiv... Read More about User-Defined Hand Gesture Interface to Improve User Experience of Learning American Sign Language.

Big data for human security: The case of COVID-19 (2022)
Journal Article
Cárdenas, P., Ivrissimtzis, I., Obara, B., Kureshi, I., & Theodoropoulos, G. (2022). Big data for human security: The case of COVID-19. Journal of Computational Science, 60, Article 101574. https://doi.org/10.1016/j.jocs.2022.101574

The COVID-19 epidemic has changed the world dramatically since societies are changing their behaviour according to the new normal, which comes along with numerous challenges and uncertainties. These uncertainties have led to instabilities in several... Read More about Big data for human security: The case of COVID-19.

Quality perception and discrimination thresholds in quantised triangle meshes (2021)
Conference Proceeding
Almutairi, A., Saarela, T., & Ivrissimtzis, I. (2021). Quality perception and discrimination thresholds in quantised triangle meshes. . https://doi.org/10.1117/12.2604720

At certain stages of the graphics pipeline, and most notably during compression for transmission and storage, triangle meshes may undergo a fixed-point arithmetic quantisation of their vertex coordinates. This paper presents the results of a psychoph... Read More about Quality perception and discrimination thresholds in quantised triangle meshes.

From Farey fractions to the Klein quartic and beyond (2021)
Journal Article
Ivrissimtzis, I., Singerman, D., & Strudwick, J. (2021). From Farey fractions to the Klein quartic and beyond. Ars mathematica contemporanea (Spletna izd.), 20(1), 37-50. https://doi.org/10.26493/1855-3974.2046.cb6

In a paper published in 1878/79 Klein produced his famous 14-sided polygon representing the Klein quartic, his Riemann surface of genus 3 which has PSL(2,7) as its automorphism group. The construction and method of side pairings are fairly complicate... Read More about From Farey fractions to the Klein quartic and beyond.

Early Fault Diagnostic System for Rolling Bearing Faults in Wind Turbines (2021)
Journal Article
Xu, L., Wang, Q., Ivrissimtzis, I., & Li, S. (2022). Early Fault Diagnostic System for Rolling Bearing Faults in Wind Turbines. Journal of Nondestructive Evaluation, Diagnostics and Prognostics of Engineering Systems, 5(1), Article 011004. https://doi.org/10.1115/1.4051222

The operation and maintenance costs of wind farms are always high due to high labor costs and the high replacement cost of parts. Thus, it is of great importance to have real-time monitoring and an early fault diagnostic system to prevent major event... Read More about Early Fault Diagnostic System for Rolling Bearing Faults in Wind Turbines.

Colour Processing in Adversarial Attacks on Face Liveness Systems (2019)
Conference Proceeding
Abduh, L., & Ivrissimtzis, I. (2019). Colour Processing in Adversarial Attacks on Face Liveness Systems. In F. P. Vidal, G. K. . L. Tam, & J. C. Roberts (Eds.), Proceedings of Computer Graphics and Visual Computing 2019 (CGVC) (149-152). https://doi.org/10.2312/cgvc.20191272

In the context of face recognition systems, liveness test is a binary classification task aiming at distinguishing between input images that come from real people’s faces and input images that come from photos or videos of those faces, and presented... Read More about Colour Processing in Adversarial Attacks on Face Liveness Systems.

Using theoretical ROC curves for analysing machine learning binary classifiers (2019)
Journal Article
Omar, L., & Ivrissimtzis, I. (2019). Using theoretical ROC curves for analysing machine learning binary classifiers. Pattern Recognition Letters, 128, 447-451. https://doi.org/10.1016/j.patrec.2019.10.004

Most binary classifiers work by processing the input to produce a scalar response and comparing it to a threshold value. The various measures of classifier performance assume, explicitly or implicitly, probability distributions Ps and Pn of the respo... Read More about Using theoretical ROC curves for analysing machine learning binary classifiers.

Trivalent expanders, $(Delta – Y)$-transformation, and hyperbolic surfaces (2019)
Journal Article
Ivrissimtzis, I., Peyerimhoff, N., & Vdovina, A. (2019). Trivalent expanders, $(Delta – Y)$-transformation, and hyperbolic surfaces. Groups, Geometry, and Dynamics, 13(3), 1103-1131. https://doi.org/10.4171/ggd/518

We construct a new family of trivalent expanders tessellating hyperbolic surfaces with large isometry groups. These graphs are obtained from a family of Cayley graphs of nilpotent groups via (Delta–Y)-transformations. We study combinatorial, topologi... Read More about Trivalent expanders, $(Delta – Y)$-transformation, and hyperbolic surfaces.

Single Image Watermark Retrieval from 3D Printed Surfaces via Convolutional Neural Networks (2018)
Conference Proceeding
Zhang, X., Wang, Q., & Ivrissimtzis, I. (2018). Single Image Watermark Retrieval from 3D Printed Surfaces via Convolutional Neural Networks. In G. Tam, & F. Vidal (Eds.), Computer Graphics & Visual Computing (CGVC) 2018 : Eurographics UK Chapter proceedings (117-120). https://doi.org/10.2312/cgvc.20182019

In this paper we propose and analyse a method for watermarking 3D printed objects, concentrating on the watermark retrieval problem. The method embeds the watermark in a planar region of the 3D printed object in the form of small semi-spherical or cu... Read More about Single Image Watermark Retrieval from 3D Printed Surfaces via Convolutional Neural Networks.

A user study on quantisation thresholds of triangle meshes (2017)
Conference Proceeding
Almutairi, A., Saarela, T., & Ivrissimtzis, I. (2017). A user study on quantisation thresholds of triangle meshes. In T. R. Wan, & F. Vidal (Eds.), Computer Graphics & Visual Computing (CGVC) 2017. Eurographics UK Chapter Proceedings, anchester Metropolitan University, United Kingdom, 14 – 15 September 2017. https://doi.org/10.2312/cgvc.20171283

We present the results of a user study on estimating a quantisation threshold above which the quantised triangle mesh is perceived as indistinguishable from its unquantised original. The design of the experiment and the analysis of the results focus... Read More about A user study on quantisation thresholds of triangle meshes.

Order-randomized Laplacian mesh smoothing (2017)
Conference Proceeding
Yang, Y., Rushmeier, H., & Ivrissimtzis, I. (2017). Order-randomized Laplacian mesh smoothing. In M. S. Floater, T. Lyche, M. Mazure, K. Mørken, & L. L. Schumaker (Eds.), Mathematical methods for curves and surfaces : 9th International Conference, MMCS 2016, Tønsberg, Norway, June 23 - June 28, 2016. Revised selected papers (312-323). https://doi.org/10.1007/978-3-319-67885-6_17

In this paper we compare three variants of the graph Laplacian smoothing. The first is the standard synchronous implementation, corresponding to multiplication by the graph Laplacian matrix. The second is a voter process inspired asynchronous impleme... Read More about Order-randomized Laplacian mesh smoothing.

Designing a facial spoofing database for processed image attacks (2016)
Conference Proceeding
Omar, L., & Ivrissimtzis, I. (2016). Designing a facial spoofing database for processed image attacks. In 7th International Conference on Imaging for Crime Detection and Prevention (ICDP 2016) : Madrid, Spain, 23-25 November 2016 ; proceedings. https://doi.org/10.1049/ic.2016.0073

Face recognition systems are used for user authentication in everyday applications such as logging into a laptop or smartphone without need to memorize a password. However, they are still vulnerable to spoofing attacks, as for example when an imposte... Read More about Designing a facial spoofing database for processed image attacks.

Reevaluating Reconstruction Filters for Path-Searching Tasks in 3D (2016)
Journal Article
Roberts, D., & Ivrissimtzis, I. (2017). Reevaluating Reconstruction Filters for Path-Searching Tasks in 3D. Computer Graphics Forum, 36(6), 291-302. https://doi.org/10.1111/cgf.12939

In this paper, we present an experiment on stereoscopic direct volume rendering, aiming at understanding the relationship between the choice of reconstruction filter and participant performance on tasks requiring spatial understanding such as 3D path... Read More about Reevaluating Reconstruction Filters for Path-Searching Tasks in 3D.

Resilience of Luminance based Liveness Tests under Attacks with Processed Imposter Images (2016)
Conference Proceeding
Omar, L., & Ivrissimtzis, I. (2016). Resilience of Luminance based Liveness Tests under Attacks with Processed Imposter Images. In V. Skala (Ed.),

Liveness tests are techniques employed by face recognition authentication systems, aiming at verifying that a live face rather than a photo is standing in front of the system camera. In this paper, we study the resilience of a standard liveness test... Read More about Resilience of Luminance based Liveness Tests under Attacks with Processed Imposter Images.

A 3D Steganalytic Algorithm and Steganalysis-Resistant Watermarking (2016)
Journal Article
Yang, Y., Pintus, R., Rushmeier, H., & Ivrissimtzis, I. (2017). A 3D Steganalytic Algorithm and Steganalysis-Resistant Watermarking. IEEE Transactions on Visualization and Computer Graphics, 23(2), 1002-2626. https://doi.org/10.1109/tvcg.2016.2525771

We propose a simple yet efficient steganalytic algorithm for watermarks embedded by two state-of-the-art 3D watermarking algorithms by Cho et al. The main observation is that while in a clean model the means/variances of Cho et al.’s normalized histo... Read More about A 3D Steganalytic Algorithm and Steganalysis-Resistant Watermarking.

Quality measures of reconstruction filters for stereoscopic volume rendering (2016)
Journal Article
Roberts, D. A., & Ivrissimtzis, I. (2016). Quality measures of reconstruction filters for stereoscopic volume rendering. Computational Visual Media, 2(1), 19-30. https://doi.org/10.1007/s41095-016-0035-7

In direct volume rendering (DVR), the choice of reconstruction filter can have a significant effect on the visual appearance of the images produced and thus, on the perceived quality of a DVR rendered scene. This paper presents the results of a subje... Read More about Quality measures of reconstruction filters for stereoscopic volume rendering.

Evaluating the Resilience of Face Recognition Systems Against Malicious Attacks (2015)
Conference Proceeding
Omar, L., & Ivrissimtzis, I. (2015). Evaluating the Resilience of Face Recognition Systems Against Malicious Attacks. In X. Xie, M. W. Jones, & G. K. L. Tam (Eds.), Proceedings of the 7th UK Computer Vision Student Workshop (BMVW) (5.1-5.9). https://doi.org/10.5244/c.29.bmvw.5

This paper presents an experiment designed to test the resilience of several user verification systems based on face recognition technology against simple identity spoofing methods, such as trying to gain access to the system by using mobile camera s... Read More about Evaluating the Resilience of Face Recognition Systems Against Malicious Attacks.

Mesh Alignment using Grid based PCA (2015)
Conference Proceeding
Kaye, D., & Ivrissimtzis, I. (2015). Mesh Alignment using Grid based PCA. In J. Braz, J. Pettré, & P. Richard (Eds.), Proceedings of the 10th International Conference on Computer Graphics Theory and Applications (VISIGRAPP 2015) : Berlin, Germany, 11-14 March 2015 (174-181). https://doi.org/10.5220/0005313801740181

We present an algorithm for mesh alignment by performing Principal Components Analysis (PCA) on a set of nodes of a regular 3D grid. The use of a 3D lattice external to both inputs increases the robustness of PCA, particularly when dealing with meshe... Read More about Mesh Alignment using Grid based PCA.

A steganalytic algorithm for 3D polygonal meshes (2014)
Conference Proceeding
Yang, Y., Pintus, R., Rushmeier, H., & Ivrissimtzis, I. (2014). A steganalytic algorithm for 3D polygonal meshes. In ICIP 2014 : 2014 IEEE International Conference on Image Processing (ICIP) (4782-4786). https://doi.org/10.1109/icip.2014.7025969

We propose a steganalytic algorithm for watermarks embedded by Cho et al.'s mean-based algorithm [1]. The main observation is that while in a clean model the means of Cho et al.'s normalized histogram bins are expected to follow a Gaussian distributi... Read More about A steganalytic algorithm for 3D polygonal meshes.

An evaluation of reconstruction filters for a path-searching task in 3D (2014)
Conference Proceeding
Roberts, D., Ivrissimtzis, I., & Holliman, N. (2014). An evaluation of reconstruction filters for a path-searching task in 3D. In 2014 Sixth International Workshop on Quality of Multimedia Experience (QoMEX 2014) : Singapore, 18-20 September 2014 (165-170). https://doi.org/10.1109/qomex.2014.6982314

The choice of reconstruction filter used to interpolate between sample points when generating images from volumetric data sets can have an impact on image quality. There are a range of reconstruction filters as well as methods to determine the qualit... Read More about An evaluation of reconstruction filters for a path-searching task in 3D.

Mesh Discriminative Features for 3D Steganalysis (2014)
Journal Article
Yang, Y., & Ivrissimtzis, I. (2014). Mesh Discriminative Features for 3D Steganalysis. ACM Transactions on Multimedia Computing, Communications and Applications, 10(3), Article 27. https://doi.org/10.1145/2535555

We propose a steganalytic algorithm for triangle meshes, based on the supervised training of a classifier by discriminative feature vectors. After a normalization step, the triangle mesh is calibrated by one step of Laplacian smoothing and then a fea... Read More about Mesh Discriminative Features for 3D Steganalysis.

Model selection for the Dubuc-Deslauriers family of subdivision schemes (2013)
Conference Proceeding
Mustafa, G., & Ivrissimtzis, I. (2013). Model selection for the Dubuc-Deslauriers family of subdivision schemes. In R. J. Cripps, G. Mullineux, & M. A. Sabin (Eds.), Mathematics of surfaces - XIV. The proceedings of a conference on the Mathematics of Surfaces, organised by the Institute of Mathematics and its Applications held at the University of Birmingham in September 2013 (155-162)

We propose two methods for model selection for the DubucDeslauriers family of subdivision schemes. In particular, we study model selection under the statistical method of cross-validation and the geometric method of minimizing the absolute discrete t... Read More about Model selection for the Dubuc-Deslauriers family of subdivision schemes.

Spectral representations of vertex transitive graphs, Archimedean solids and finite Coxeter groups (2013)
Journal Article
Ivrissimtzis, I., & Peyerimhoff, N. (2013). Spectral representations of vertex transitive graphs, Archimedean solids and finite Coxeter groups. Groups, Geometry, and Dynamics, 7(3), 591-615. https://doi.org/10.4171/ggd/199

In this article, we study eigenvalue functions of varying transitionprobability matrices on finite, vertex transitive graphs. We provethat the eigenvalue function of an eigenvalue of fixed highermultiplicity has a critical point if and only if the co... Read More about Spectral representations of vertex transitive graphs, Archimedean solids and finite Coxeter groups.

Linear Correlations between Spatial and Normal Noise in Triangle Meshes (2013)
Journal Article
Yang, Y., Norbert, P., & Ivrissimtzis, I. (2013). Linear Correlations between Spatial and Normal Noise in Triangle Meshes. IEEE Transactions on Visualization and Computer Graphics, 19(1), 45-55. https://doi.org/10.1109/tvcg.2012.106

We study the relationship between the noise in the vertex coordinates of a triangle mesh and normal noise. First, we compute in closed form the expectation for the angle  between the new and the old normal when uniform noise is added to a single ver... Read More about Linear Correlations between Spatial and Normal Noise in Triangle Meshes.

Efficient construction of the Čech complex (2012)
Journal Article
Dantchev, S., & Ivrissimtzis, I. (2012). Efficient construction of the Čech complex. Computers and Graphics, 36(6), 708-713. https://doi.org/10.1016/j.cag.2012.02.016

In many applications, the first step into the topological analysis of a discrete point set P sampled from a manifold is the construction of a simplicial complex with vertices on P. In this paper, we present an algorithm for the efficient computation... Read More about Efficient construction of the Čech complex.

Polygonal mesh watermarking using Laplacian coordinates (2010)
Journal Article
Yang, Y., & Ivrissimtzis, I. (2010). Polygonal mesh watermarking using Laplacian coordinates. Computer Graphics Forum, 29(5), 1585-1593. https://doi.org/10.1111/j.1467-8659.2010.01767.x

We propose a watermarking algorithm for polygonal meshes based on the modification of the Laplacian coordinates. More specifically, we first compute the Laplacian coordinates (x; y; z) of the mesh vertices, then construct the histogram of the lengths... Read More about Polygonal mesh watermarking using Laplacian coordinates.

Implicit surface reconstruction and feature detection with a learning algorithm (2010)
Conference Proceeding
Kaye, D., & Ivrissimtzis, I. (2010). Implicit surface reconstruction and feature detection with a learning algorithm. In J. Collomosse, & I. Grimstead (Eds.),

We propose a new algorithm for implicit surface reconstruction and feature detection. The algorithm is based on a self organising map with the connectivity of a regular 3D grid that can be trained into an implicit representation of surface data. The... Read More about Implicit surface reconstruction and feature detection with a learning algorithm.

Effects of Noise on Quantized Triangle Meshes (2010)
Conference Proceeding
Ivrissimtzis, I. (2010). Effects of Noise on Quantized Triangle Meshes. In M. Dahlen, M. Floater, T. Lyche, J. Merrien, K. Morken, & L. Schumaker (Eds.), Mathematical methods for curves and surfaces : 7th International Conference, MMCS 2008, 26 June - 1 July, 2008, Tønsberg, Norway ; revised selected papers (274-284). https://doi.org/10.1007/978-3-642-11620-9_18

In this paper we measure the effects of noise on the performance of a standard entropy compression algorithm for quantized triangle meshes. In a first experiment, we show that a small amount of added noise may lead to slightly smaller filesizes. The... Read More about Effects of Noise on Quantized Triangle Meshes.

Curve subdivision with arc-length control. (2009)
Journal Article
Hernandez-Mederos, V., Estrada-Sarlabous, J., Morales, S., & Ivrissimtzis, I. (2009). Curve subdivision with arc-length control. Computing, 86(2-3), 151-169. https://doi.org/10.1007/s00607-009-0068-1

In this paper we present a new nonstationary, interpolatory, curve subdivision scheme. We show that the scheme converges and the subdivision curve is continuous. Moreover, starting with the chord length parametrization of the initial polygon, we obta... Read More about Curve subdivision with arc-length control..

Distance Based Feature Detection on 3D Point Sets. (2009)
Conference Proceeding
Ahmad, R., & Ivrissimtzis, I. (2009). Distance Based Feature Detection on 3D Point Sets. In W. Tang, & J. Collomosse (Eds.), Theory and practice of computer graphics 2009: Eurographics UK Chapter proceedings ; Cardiff University, United Kingdom, 17th to 19th June 2009; [papers presented at the 6th Theory and Practice of Computer Graphics Conference (TP.CG.09)] (53-56)

Variational Bayesian noise estimation of point sets. (2009)
Journal Article
Yoon, M., Ivrissimtzis, I., & Lee, S. (2009). Variational Bayesian noise estimation of point sets. Computers and Graphics, 33(3), 226 - 234. https://doi.org/10.1016/j.cag.2009.03.019

Scanning devices acquire geometric information from the surface of an object in the form of a 3D point set. Such point sets, as any data obtained by means of physical measurement, contain some noise. To create an accurate model of the scanned object,... Read More about Variational Bayesian noise estimation of point sets..

Multi-pen Sketch Recognition in a Learning Environment. (2009)
Journal Article
Don, L., & Ivrissimtzis, I. (2009). Multi-pen Sketch Recognition in a Learning Environment. Journal of multimedia, 4(2), 80-86. https://doi.org/10.4304/jmm.4.2.80-86

Virtual physics environments are becoming increasingly popular as a teaching tool for high school level mechanical physics. While useful, these tools often offer a complex user interface, lacking the intuitive nature of the traditional whiteboard. Fu... Read More about Multi-pen Sketch Recognition in a Learning Environment..

Multi-Colour Sketch Recognition in a Learning Environment (2008)
Conference Proceeding
Don, L., & Ivrissimtzis, I. (2008). Multi-Colour Sketch Recognition in a Learning Environment. In L. Li, T. Shih, Q. L. Li, S. Yang, & Q. Zhou (Eds.), 1st IEEE International Conference on Ubi-Media Computing, 15-16 July 2008, Lanzhou, China ; proceedings (441-443). https://doi.org/10.1109/umedia.2008.4570932

Virtual physics environments are becoming increasingly popular as a teaching tool for grade and high school level mechanical physics. While useful, these tools often offer a complex user interface, lacking the intuitive nature of the traditional whit... Read More about Multi-Colour Sketch Recognition in a Learning Environment.

Self-Organising Maps for Implicit Surface Reconstruction (2008)
Conference Proceeding
Yoon, M., Ivrissimtzis, I., & Lee, S. (2008). Self-Organising Maps for Implicit Surface Reconstruction. In I. S. Lim, & W. Tang (Eds.),

This paper proposes an implicit surface reconstruction algorithm based on Self-Organising Maps (SOMs). The SOM has the connectivity of a regular 3D grid, each node storing its signed distance from the surface. At each iteration of the basic algorithm... Read More about Self-Organising Maps for Implicit Surface Reconstruction.

Subdivision Surfaces and Applications (2008)
Book Chapter
Catalano, C., Ivrissimtzis, I., & Nasri, A. (2008). Subdivision Surfaces and Applications. In L. De Floriani, & M. Spagnuolo (Eds.), Shape analysis and structuring (115-143). Springer Verlag. https://doi.org/10.1007/978-3-540-33265-7_4

After a short introduction on the fundamentals of subdivision surfaces, the more advanced material of this chapter focuses on two main aspects. First, shape interrogation issues are discussed; in particular, artifacts, typical of subdivision surfaces... Read More about Subdivision Surfaces and Applications.

Point Set Denoising using a Variational Bayesian Method (2008)
Journal Article
Yoon, M., & Ivrissimtzis, I. (2008). Point Set Denoising using a Variational Bayesian Method. Jeongbo gwahaghoe nonmunji. keompyuting ui silje, 14(5), 527-531

For statistical modeling, the model parameters are usually estimated by maximizing a probability measure, such as the likelihood or the posterior. In contrast, a variational Bayesian method threats the parameters of the model as probability distribut... Read More about Point Set Denoising using a Variational Bayesian Method.

Surface and normal ensembles for surface reconstruction (2007)
Journal Article
Yoon, M., Lee, Y., Lee, S., Ivrissimtzis, I., & Seidel, H. (2007). Surface and normal ensembles for surface reconstruction. Computer-Aided Design, 39(5), 408-420. https://doi.org/10.1016/j.cad.2007.02.008

The majority of the existing techniques for surface reconstruction and the closely related problem of normal reconstruction are deterministic. Their main advantages are the speed and, given a reasonably good initial input, the high quality of the rec... Read More about Surface and normal ensembles for surface reconstruction.

Surface Reconstruction with Neural Meshes. (2005)
Conference Proceeding
Ivrissimtzis, I., Jeong, W., Lee, S., Lee, Y. L., & Seidel, H. (2005). Surface Reconstruction with Neural Meshes. In M. Daehlen, K. Morken, & L. Schumaker (Eds.),

We describe a Learning algorithm for surface reconstruction based on an incrementally expanding Neural Network known as Growing Cell Structure. The Neural Network (Neural Mesh) expands by splitting its most active vertices and removing its least acti... Read More about Surface Reconstruction with Neural Meshes..

On the support of recursive subdivision (2004)
Journal Article
Ivrissimtzis, I., Sabin, M., & Dodgson, N. (2004). On the support of recursive subdivision. ACM Transactions on Graphics, 23(4), 1043-1060. https://doi.org/10.1145/1027411.1027417

We study the support of subdivision schemes: that is, the region of the subdivision surface, which is affected by the displacement of a single control point. Our main results cover the regular case, where the mesh induces a regular Euclidean tessella... Read More about On the support of recursive subdivision.

Evolutions of Polygons in the Study of Subdivision Surfaces (2004)
Journal Article
Ivrissimtzis, I., & Seidel, H. (2004). Evolutions of Polygons in the Study of Subdivision Surfaces. Computing, 72(1-2), 93-103. https://doi.org/10.1007/s00607-003-0049-8

We employ the theory of evolving n-gons in the study of subdivision surfaces. We show that for subdivision schemes with small stencils the eige¬nanalysis of an evolving polygon, corresponding either to a face or to the 1-¬ring neighborhood of a verte... Read More about Evolutions of Polygons in the Study of Subdivision Surfaces.

A generative classification of mesh refinement rules with lattice transformations (2004)
Journal Article
Ivrissimtzis, I., Dodgson, N., & Sabin, M. (2004). A generative classification of mesh refinement rules with lattice transformations. Computer Aided Geometric Design, 21(1), 99-109. https://doi.org/10.1016/j.cagd.2003.08.001

We give a classification of subdivision refinement rules using similarity transformations of lattices. Our work expands recent results in the classification of primal triangular subdivision. In the examples we concentrate on the cases with a low rati... Read More about A generative classification of mesh refinement rules with lattice transformations.

The refinability of the 4-point scheme. (2002)
Journal Article
Ivrissimtzis, I., Dodgson, N., Hassan, M., & Sabin, M. (2002). The refinability of the 4-point scheme. Computer Aided Geometric Design, 19(4), 235-238

An interpolating 4-point C2 ternary stationary subdivision scheme (2002)
Journal Article
Hassan, M., Ivrissimtzis, I., Dodgson, N., & Sabin, M. (2002). An interpolating 4-point C2 ternary stationary subdivision scheme. Computer Aided Geometric Design, 19(1), 1-18. https://doi.org/10.1016/s0167-8396%2801%2900084-x

A novel 4-point ternary interpolatory subdivision scheme with a tension parameter is analyzed. It is shown that for a certain range of the tension parameter the resulting curve is C2. The role of the tension parameter is demonstrated by a few example... Read More about An interpolating 4-point C2 ternary stationary subdivision scheme.