Browsing by Author "Tang, Wen"

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    Break and Splice: A Statistical Method for Non‐Rigid Point Cloud Registration
    (© 2023 Eurographics ‐ The European Association for Computer Graphics and John Wiley & Sons Ltd., 2023) Gao, Qinghong; Zhao, Yan; Xi, Long; Tang, Wen; Wan, Tao Ruan; Hauser, Helwig and Alliez, Pierre
    3D object matching and registration on point clouds are widely used in computer vision. However, most existing point cloud registration methods have limitations in handling non‐rigid point sets or topology changes (. connections and separations). As a result, critical characteristics such as large inter‐frame motions of the point clouds may not be accurately captured. This paper proposes a statistical algorithm for non‐rigid point sets registration, addressing the challenge of handling topology changes without the need to estimate correspondence. The algorithm uses a novel  framework to treat the non‐rigid registration challenges as a reproduction process and a Dirichlet Process Gaussian Mixture Model (DPGMM) to cluster a pair of point sets. Labels are assigned to the source point set with an iterative classification procedure, and the source is registered to the target with the same labels using the Bayesian Coherent Point Drift (BCPD) method. The results demonstrate that the proposed approach achieves lower registration errors and efficiently registers point sets undergoing topology changes and large inter‐frame motions. The proposed approach is evaluated on several data sets using various qualitative and quantitative metrics. The results demonstrate that the  framework outperforms state‐of‐the‐art methods, achieving an average error reduction of about 60% and a registration time reduction of about 57.8%.
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    Just Noticeable Difference of Dead Pixels in Monochrome Computer-Generated Holograms
    (The Eurographics Association, 2023) Lindfield, Nicholas; Carey, Remington; Hulusic, Vedad; Milne, Darran; Tang, Wen; Vangorp, Peter; Hunter, David
    Computer-generated holography (CGH) is a method for replicating scenes that incorporates depth, making them potentially much more realistic than traditional displays. Because CGH uses diffractive optics to generate scenes, holograms are also significantly more robust against dead pixels: while a single dead pixel is often noticeable in traditional displays, in holography much higher numbers are needed before a viewer realises the issue. This work is a pilot study to determine the Just Noticeable Difference of the number of dead pixels of a hologram, i.e., the minimum amount that need to be added before a viewer notices the difference. From these JNDs a quality ruler will be generated, which later work will use to compare the impact of other distortions on the perceived quality of a hologram. Results thus far suggest an addition of 4% dead pixels is required to notice a difference, which is significantly greater than the tolerance observed for traditional displays, where the fault class threshold is less than 0.05%.
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    User eXperience in educational eXtended Reality applications in the Cultural Heritage domain
    (The Eurographics Association, 2023) Liu, Wenjun; Hargood, Charlie; Tang, Wen; Hulusic, Vedad; Bucciero, Alberto; Fanini, Bruno; Graf, Holger; Pescarin, Sofia; Rizvic, Selma
    With the increasing prevalence of educational eXtended Reality (XR) Cultural Heritage (CH) experiences, it becomes increasingly important to understand the user, and learner, experience of such installations and develop bespoke methodologies to capture and evaluate these experiences. Our work aims to expand the existing knowledge of User Experience (UX) in CH incorporating XR, especially for educational aspects inside, by displaying and analysing UX understanding and evaluation methods. Through investigation and research on UX work of applications described from various sources, this paper summarises the current trends, limitations, and challenges of UX evaluation in this field and represents the direction of future work.