CCGV concentrates on research in computer graphics, computer animation and medical visualisation.

Recent Submissions

  • 3D-holoscopic imaging: a new dimension to enhance Iimaging in minimally invasive therapy in urologic oncology

    Makanjuola, Jonathan K.; Aggoun, Amar; Swash, Mohammad; Grange, Philippe C.R.; Challacombe, Benjamin; Dasgupta, Prokar; Guy's and St Thomas' Hospital; Brunel University; King's College Hospital (Mary Ann Liebert, 2013-05)
    Background and Purpose: Existing imaging modalities of urologic pathology are limited by three-dimensional (3D) representation on a two-dimensional screen. We present 3D-holoscopic imaging as a novel method of representing Digital Imaging and Communications in Medicine data images taken from CT and MRI to produce 3D-holographic representations of anatomy without special eyewear in natural light. 3D-holoscopic technology produces images that are true optical models. This technology is based on physical principles with duplication of light fields. The 3D content is captured in real time with the content viewed by multiple viewers independently of their position, without 3D eyewear. Methods: We display 3D-holoscopic anatomy relevant to minimally invasive urologic surgery without the need for 3D eyewear. Results: The results have demonstrated that medical 3D-holoscopic content can be displayed on commercially available multiview auto-stereoscopic display. Conclusion: The next step is validation studies comparing 3D-Holoscopic imaging with conventional imaging.
  • The refocusing distance of a standard plenoptic photograph

    Hahne, Christopher; Aggoun, Amar; Velisavljević, Vladan; University of Bedfordshire (IEEE, 2015-06-12)
    In the past years, the plenoptic camera aroused an increasing interest in the field of computer vision. Its capability of capturing three-dimensional image data is achieved by an array of micro lenses placed in front of a traditional image sensor. The acquired light field data allows for the reconstruction of photographs focused at different depths. Given the plenoptic camera parameters, the metric distance of refocused objects may be retrieved with the aid of geometric ray tracing. Until now there was a lack of experimental results using real image data to prove this conceptual solution. With this paper, the very first experimental work is presented on the basis of a new ray tracing model approach, which considers more accurate micro image centre positions. To evaluate the developed method, the blur metric of objects in a refocused image stack is measured and compared with proposed predictions. The results suggest quite an accurate approximation for distant objects and deviations for objects closer to the camera device.
  • Healthcare-event driven semantic knowledge extraction with hybrid data repository

    Yu, Hong Qing; Zhao, Xia; Zhen, Xin; Dong, Feng; Liu, Enjie; Clapworthy, Gordon J.; University of Bedfordshire (IEEE, 2014-08)
    In this paper, we introduce a Healthcare-Event (H-event) based knowledge extraction approach on a hybrid data repository. The repository collects (with individual user's permission) dynamic and large volume healthcare related data from various resources such as wearable sensors, social media Web APIs and our application itself. The proposed extraction approach relies on two data processing processes. One is the data integration process to dynamically retrieving the large data using public data service APIs. The first process also generates a set of big knowledge bases and stored in NoSQL storage. This paper will focus on the second extraction process that is the H-Event based ontological knowledge extraction for detecting and monitoring user's healthcare related situations, such as medical symptoms, treatments, conditions and daily activities from the NoSQL knowledge bases. The second process can be seen as post-processing step to detect more explicit healthcare knowledge about personalised health conditions and represent the knowledge using RDF formats in a semantic triple repository to enhance further data analytics.
  • Support for the calculation of stent fatigue fracture in peripheral arteries

    McFarlane, Nigel J.B.; Wei, Hui; Zhao, Youbing; Clapworthy, Gordon J.; Testi, Debora; Chiarini, Alessandro; University of Bedfordshire (European Association for Computer Graphics, 2013)
    Vascular stenting is a medical intervention in which a wire mesh tube is inserted into an artery or vein to provide internal support. This is a safe and common procedure, but stents are now increasingly being deployed in peripheral locations, such as the femoral artery, as part of a procedure called Peripheral Vascular Angioplasty (PVA). Stents in such locations are subject to cyclic bending, and are therefore at risk of fatigue fracture. This paper describes the work of the RT3S project, which brings together stent modelling, surgical simulation and risk calculation for surgical planning. This will allow the clinical user to interactively assess different stent models and deployment options for breakage risk. In the RT3S system, models of several commercial models of self-expanding stent are available for simulation. The placement of the stent in the vessel and the withdrawal of the catheter sheath to expand the stent are visualised. A simplex control mesh is used to guide the deformation of the stent from its compressed start configuration to its expanded final position. The fracture risk for the given model and its patient-specific final position is precomputed using the response surfaces methodology.
  • A cross-platform approach to the treatment of ambylopia

    Wei, Hui; Zhao, Youbing; Dong, Feng; Saleh, George; Ye, Xujiong; Clapworthy, Gordon J.; University of Bedfordshire (IEEE, 2013-11)
    In this paper, we introduce a diagnosis and treatment for amblyopia performed through a game suitable for children aged between 3 and 7. Our method places emphasis on cooperation between the two eyes to achieve a good binocular outcome to aid the recovery of depth perception. Our approach is not limited to a particular device or platform nor even to a particular form of game. Several prototype games have been developed, including 2D games and 3D games.
  • Pre-surgery planning in vascular procedures: an introduction to the RT3S project

    Dubini, Gabriele; Guarneri, Maria Renata; Clapworthy, Gordon J.; Katsaounis, Nassos; Lawford, Patricia; Petrakis, Euripides; Rochette, Michel; Silvestro, Claudio; Testi, Debora; Politec. di Milano; et al. (IEEE, 2013-11)
    RT3S is an EU-funded project in an area of e-health - ICT for Patient Safety. Specifically, RT3S is developing a patient-centred, probabilistic model for peripheral stent fatigue-fracture, integrated within a real-time, computer-aided surgery planning application. RT3S will provide advice on fracture risk for individual combinations of patient anatomy and stent design. Alongside the pre-operational software tool, which is addressed mainly to interventional radiologists, RT3S has also developed a training application that will be of benefit to trainee vascular interventionists and engineers in medical device companies. This paper provides an overview of the work performed during nearly three years of project activities and also addresses the motivation leading to RT3S and the expected impact.
  • WebGL-based interactive rendering of whole body anatomy for web-oriented visualisation of avatar-centered digital health data

    Zhao, Youbing; Zhao, X.; Dong, Feng; Clapworthy, Gordon J.; Ersotelos, Nikolaos; Liu, Enjie; University of Bedfordshire (IEEE, 2013-11)
    The visualisation of whole-body anatomy has a variety of applications in health-related analysis and simulation. However, the rendering of complex 3D human anatomy models is generally performed by standalone applications rather than via a web interface, as rendering large 3D models has always been a weak spot of traditional web browsers. Consequently, online access to, and exploration of, the human anatomy in 3D has not been feasible in the past. With the advent of WebGL and HTML5, high performance OpenGL rendering seamlessly integrated with the web interface is now within reach, and this opens the possibility of visualising avatar-centered health data via a web interface. In this paper, a WebGL-based prototype for rendering whole-body anatomy is introduced, and the technical details are presented.
  • Dynamic PCI assignment in two-tier networks based on cell activity prediction

    Zhang, J.; Zhang, X.; Xiao, Z.; Liu, Enjie; University of Bedfordshire; Hunan University; University of Sheffield (IET, 2013-11)
    Physical cell identity (PCI) is used to identify each cell. However, with the introduction of femtocells, 8 bytes allocation for PCI cannot accommodate a large number of femtocells. The current solution in 3GPP Release 9 is to use cell global identity associated with PCI to resolve this problem. However, this solution may incur higher inbound handover failure. A dynamic PCI assignment based on cell activity level prediction is proposed. The system level simulation showed that the approach outperforms the existing approaches.
  • Enhancing Bayesian estimators for removing camera shake

    Wang, Chao; Yue, Y.; Dong, Feng; Tao, Yubo; Ma, Xiangyin; Clapworthy, Gordon J.; Ye, Xujiong; University of Bedfordshire (Wiley, 2013)
    The aim of removing camera shake is to estimate a sharp version x from a shaken image y when the blur kernel k is unknown. Recent research on this topic evolved through two paradigms called MAP(k) and MAP(x,k). MAP(k) only solves for k by marginalizing the image prior, while MAP(x,k) recovers both x and k by selecting the mode of the posterior distribution. This paper first systematically analyses the latent limitations of these two estimators through Bayesian analysis. We explain the reason why it is so difficult for image statistics to solve the previously reported MAP(x,k) failure. Then we show that the leading MAP(x,k) methods, which depend on efficient prediction of large step edges, are not robust to natural images due to the diversity of edges. MAP(k), although much more robust to diverse edges, is constrained by two factors: the prior variation over different images, and the ratio between image size and kernel size. To overcome these limitations, we introduce an inter-scale prior prediction scheme and a principled mechanism for integrating the sharpening filter into MAP(k). Both qualitative results and extensive quantitative comparisons demonstrate that our algorithm outperforms state-of-the-art methods.
  • A user interface design for a patient oriented digital patient

    Ersotelos, Nikolaos; Zhao, Xia; Zhao, Youbing; Wei, Hui; Liu, Enjie; Clapworthy, Gordon J.; Dong, Feng; University of Bedfordshire (IEEE, 2013-11)
    MyHealthAvatar is designed to provide a digital representation of patient health status. It aims to become a `lifetime companion' for individual citizens that will facilitate the collection of, and access to, long term health-status information. This avatar is not only extremely valuable for clinical decision-making, but it will generate data to support clinical investigation, thereby leading to strengthened multidisciplinary research and excellence in supporting innovative medical care across the population. My Health Avatar platform is currently under development. The purpose of this paper is to present the scope, the provided service and the future plans of the platform as well as a detailed description of the visual representation of the MyHealthAvatar platform.
  • A scalable data repository for recording self-managed longitudinal health data of digital patients

    Zhao, Xia; Zhao, Youbing; Ersotelos, Nikolaos; Fan, Dina; Liu, Enjie; Clapworthy, Gordon J.; Dong, Feng; University of Bedfordshire (2013-11)
    This paper presents the proof-of-concept design of the data repository for 4D digital avatars in the MyHealthAvatar project. Taking account of the privacy and legal issues of patient health information, the research generates a set of synthetic data based on publicly available survey data. At the prototype stage, these synthetic data are used in the scenarios of data storage and management. The paper discusses the early proof-of-concept design of the technical stack which enables the storage and query of large scale patients' health data and empowers the future data mining and analysis for health care support. It provides the first stage implementation and the use of it for data analytics.
  • AimaSimul: a software tool to plan stent positioning in peripheral arteries and evaluate the associated fatigue fracture risk

    Testi, Debora; McFarlane, Nigel J.B.; Wei, Hui; Zhao, Youbing; Clapworthy, Gordon J.; Ryan, D. M.; Lawford, Patricia; University of Bedfordshire; CINECA Supercomput. Centre (IEEE, 2013-11)
    Vascular stent deployment in peripheral arteries is a medical intervention in which a wire mesh tube is inserted into the artery to provide internal support. However, stents positioned in locations such as the femoral artery are subject to cyclic bending, and are therefore at risk of fatigue fracture. A software tool chain, called AimaSimul, is being implemented to support stent modeling, surgical simulation and risk calculation for surgical planning. In particular, the AimaSimul preoperative planning tool allows clinicians, starting from patient-specific medical images, to interactively assess different stent models and deployment options for the risk of breakage. This paper describes the main functionalities of AimaSimul and, in particular, the stent deployment and deformation.
  • Parallel centerline extraction on the GPU

    Liu, Baoquan; Telea, Alexandru C.; Roerdink, Jos B.T.M.; Clapworthy, Gordon J.; Williams, David; Yang, Po; Dong, Feng; Codreanu, Valeriu; Chiarini, Alessandro; University of Bedfordshire; et al. (Elsevier, 2014-06)
    Centerline extraction is important in a variety of visualization applications including shape analysis, geometry processing, and virtual endoscopy. Centerlines allow accurate measurements of length along winding tubular structures, assist automatic virtual navigation, and provide a path-planning system to control the movement and orientation of a virtual camera. However, efficiently computing centerlines with the desired accuracy has been a major challenge. Existing centerline methods are either not fast enough or not accurate enough for interactive application to complex 3D shapes. Some methods based on distance mapping are accurate, but these are sequential algorithms which have limited performance when running on the CPU. To our knowledge, there is no accurate parallel centerline algorithm that can take advantage of modern many-core parallel computing resources, such as GPUs, to perform automatic centerline extraction from large data volumes at interactive speed and with high accuracy. In this paper, we present a new parallel centerline extraction algorithm suitable for implementation on a GPU to produce highly accurate, 26-connected, one-voxel-thick centerlines at interactive speed. The resulting centerlines are as accurate as those produced by a state-of-the-art sequential CPU method [40], while being computed hundreds of times faster. Applications to fly through path planning and virtual endoscopy are discussed. Experimental results demonstrating centeredness, robustness and efficiency are presented.
  • Dynamic user equipment-based hysteresis-adjusting algorithm in LTE femtocell networks

    Xiao, Zhu; Zhang, Xu; Maple, Carsten; Allen, Ben; Liu, Enjie; Mahato, Shyam Babu; University of Bedfordshire; Southeast University, Nanjing; Hunan University, Chang sha; University of Warwick (IEEE, 2014-09)
    In long-term evolution (LTE) femtocell networks, hysteresis is one of the main parameters which affects the performance of handover with a number of unnecessary handovers, including ping-pong, early, late and incorrect handovers. In this study, the authors propose a hybrid algorithm that aims to obtain the optimised unique hysteresis for an individual mobile user moving at various speeds during the inbound handover process. This algorithm is proposed for two-tier scenarios with macro and femto. The centralised function in this study evaluates the overall handover performance indicator. Then, the handover aggregate performance indicator (HAPI) is used to determine an optimal configuration. Based on the received reference signal-to-interference-plus-noise ratio, the distributed function residing on the user equipment (UE) is able to obtain an optimal unique hysteresis for the individual UE. Theoretical analysis with three indication boundaries is provided to evaluate the proposed algorithm. A system-level simulation is presented, and the proposed algorithm outperformed the existing approaches in terms of handover failure, call-drop and redundancy handover ratios and also achieved better overall system performance.
  • Performance analysis of a generalized and autonomous DRX scheme

    Liu, Enjie; Ren, Weili; University of Bedfordshire (IEEE, 2014-07)
    A generalized and autonomous DRX (discontinuous reception) scheme, applicable to both 3GPP and IEEE 802.16e standards, is analyzed by two - level Markov chain modeling along with the ETSI packet traffic model. Numerical analysis showed that this scheme is capable of autonomously adjusting DRX cycle to keep up with changing UE activity level with no signaling overhead increase, thus produces a better tuned DRX operation. Quantitative comparison with the power saving schemes of 3GPP and 802.16e standards demonstrated that it is advantageous over and generalization of these power saving schemes.
  • Synopsis of an engineering solution for a painful problem - phantom limb pain

    Mousavi, A.; Cole, J.; Kalganova, T.; Stone, R.; Zhang, J.; Pettifer, S.; Walker, R.; Nikopoulou-Smyrni, P.; Henderson Slater, D.; Aggoun, Amar; et al. (Scitepress, 2014)
    This paper is synopsis of a recently proposed solution for treating patients who suffer from Phantom Limb Pain (PLP). The underpinning approach of this research and development project is based on an extension of "mirror box" therapy which has had some promising results in pain reduction. An outline of an immersive individually tailored environment giving the patient a virtually realised limb presence, as a means to pain reduction is provided. The virtual 3D holographic environment is meant to produce immersive, engaging and creative environments and tasks to encourage and maintain patients' interest, an important aspect in two of the more challenging populations under consideration (over-60s and war veterans). The system is hoped to reduce PLP by more than 3 points on an 11 point Visual Analog Scale (VAS), when a score less than 3 could be attributed to distraction alone.
  • Dynamic hyperlinker for 3D content search and retrieval

    Swash, M.R.; Aggoun, Amar; Fatah, O. Abdul; Li, B.; Fernandez, Juan C. J.; Tsekleves, Emmanuel; Brunel University; University of Bedfordshire (IEEE, 2013-06)
    Recently, 3D display technology, and content preparation and creation tools have been under vigorous development. Consequently, they are also widely adopted by home and professional users. 3D digital repositories are increasing and becoming available ubiquitously. However, there is not yet a single 3D content search and retrieval platform. In this paper, we propose and present the development of a novel approach for 3D content search and retrieval which is called Dynamic hyperlinker for 3D content search and retrieval. It advances 3D multimedia navigability and searchability by creating dynamic links for selectable and clickable objects in the scene while the 3D video clip is being replayed. The proposed system involves 3D video processing, such as detecting/tracking clickable objects, annotating objects, and metadata engineering. Such system attracts the attention from both home and professional users such as broadcasters and digital content providers. The experiment is conducted on Holoscopic 3D images “also known as integral images.
  • Reference based holoscopic 3D camera aperture stitching for widening the overall viewing angle

    Swash, M.R.; Fernandez, Juan C. J.; Aggoun, Amar; Fatah, O. Abdul; Tsekleves, Emmanuel; Brunel University; University of Bedfordshire (IEEE, 2014-07)
    Holoscopic 3D imaging also known as Integral imaging is a promising technique for creating full color 3D optical models that exist in space independently of the viewer. The images exhibit continuous parallax throughout the viewing zone. In order to achieve depth control, robust and real-time, a single aperture holoscopic 3D imaging camera is used for recording holoscopic 3D image using a regularly spaced array of small lenslets, which view the scene at a slightly different angle to its neighbour. However, the main problem the holoscopic 3D camera aperture faces is that it is not big enough for recording larger scene with existing 2D camera sensors. This paper proposes a novel reference based holoscopic 3D camera aperture stitching method that enlarges overall viewing angle of the holoscopic 3D camera in post-production after the capture.
  • Precise foreground detection algorithm using motion estimation, minima and maxima inside the foreground object

    Nawaz, Muhammad; Cosmas, John; Lazaridis, Pavlos I.; Zaharis, Zaharias D.; Zhang, Yue; Mohib, Hamdullah; Brunel University; University of Bedfordshire (IEEE, 2013)
    In this paper the precise foreground mask is obtained in a complex environment by applying simple and effective methods on a video sequence consisting of multi-colour and multiple foreground object environment. To detect moving objects we use a simple algorithm based on block-based motion estimation, which requires less computational time. To obtain a full and improved mask of the moving object, we use an opening-and-closing-by-reconstruction mechanism to identify the minima and maxima inside the foreground object by applying a set of morphological operations. This further enhances the outlines of foreground objects at various stages of image processing. Therefore, the algorithm does not require the knowledge of the background image. That is why it can be used in real world video sequences to detect the foreground in cases where we do not have a background model in advance. The comparative performance results demonstrate the effectiveness of the proposed algorithm.
  • Super depth-map rendering by converting holoscopic viewpoint to perspective projection

    Alazawi, E.; Abbod, M.; Aggoun, Amar; Swash, M.R.; Fatah, O. Abdul; Fernandez, Juan C. J.; University of Bedfordshire; Brunel University (IEEE, 2014-07)
    The expansion of 3D technology will enable observers to perceive 3D without any eye-wear devices. Holoscopic 3D imaging technology offers natural 3D visualisation of real 3D scenes that can be viewed by multiple viewers independently of their position. However, the creation of a super depth-map and reconstruction of the 3D object from a holoscopic 3D image is still in its infancy. The aim of this work is to build a high-quality depth map of a real 3D scene from a holoscopic 3D image through extraction of multi-view high resolution Viewpoint Images (VPIs) to compensate for the poor features of VPIs. To manage this, we propose a reconstruction method based on the perspective formula to convert sets of directional orthographic low resolution VPIs into perspective projection geometry. Following that, we implement an Auto-Feature point algorithm for synthesizing VPIs to distinctive Feature-Edge (FE) blocks to localize and provide an individual feature detector that is responsible for integration of 3D information. Detailed experiments proved the reliability and efficiency of the proposed method, which outperforms state-of-the-art methods for depth map creation.

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