• Baseline of virtual cameras acquired by a standard plenoptic camera setup

      Hahne, Christopher; Aggoun, Amar; Haxha, Shyqyri; Velisavljević, Vladan; Fernandez, Juan C. J.; University of Bedfordshire (IEEE, 2014-07-03)
      Plenoptic cameras have been used to computationally generate viewpoint images from the captured light field. This paper aims to provide a prediction of corresponding virtual camera positions based on the parameters of a standard plenoptic camera setup. Furthermore, by tracing light rays from the sensor to the object space, a solution is proposed to estimate the baseline of viewpoints. By considering geometrical optics, the suggested approach has been implemented in Matlab and assessed using Zemax, a real ray tracing simulation tool. Thereby, the impact of different main lens locations is investigated. Results of the baseline approximation indicate that estimates obtained by the proposed model deviate by less than 0.2% compared to the complex real ray tracing method.
    • Building highly realistic facial modeling and animation: a survey

      Ersotelos, Nikolaos; Dong, Feng (SpringerLink, 2008)
      This paper provides a comprehensive survey on the techniques for human facial modeling and animation. The survey is carried out from two different perspectives: facial modeling, which concerns how to produce 3D face models, and facial animation, which regards how to synthesize dynamic facial expressions. To generate an individual face model, we can either perform individualization of a generic model or combine face models from an existing face collection. With respect to facial animation, we have further categorized the techniques into simulation-based, performance-driven and shape blend-based approaches. The strength and weakness of these techniques within each category are discussed, alongside with the applications of these techniques to various exploitations. In addition, a brief historical review of the technique evolution is provided. Limitations and future trend are discussed. Conclusions are drawn at the end of the paper.
    • CCVis: a software plugin for unified visualisation in ContraCancrum based on VTK extensions

      Zhao, Youbing; Clapworthy, Gordon J.; Tao, Yubo; Dong, Feng; Wei, Hui; Wang, Tao (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2011-07)
    • Clinically driven design of multi-scale cancer models: the ContraCancrum project paradigm

      Marias, Kostas; Dionysiou, D.; Sakkalis, Vangelis; Graf, N.; Bohle, R.M.; Coveney, Peter V.; Wan, S.; Folarin, A.; Buchler, P.; Reyes, M.; et al. (The Royal Society, 2011-06-06)
    • Contour synthesis by least-squares construction

      Dong, Feng; Clapworthy, Gordon J.; Lin, Hai (IET, 2009-10-08)
    • 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.
    • Deposition of charged inhaled aerosols with transient airflow in sequential lung airway model

      Koolpiruck, Diew; Prakoonwit, Simant; Balachandran, Wamadeva (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2004)
    • The development of a parallel ray launching algorithm for wireless network planning

      Lai, Zhihua; Bessis, Nik; De La Roche, Guillaume; Kuonen, Pierre; Zhang, Jie; Clapworthy, Gordon J. (IGI Publishing, 2011)
    • Diode-based IQ imbalance estimation in direct conversion transmitters

      Xiong, Jian; Zhang, Yue; Li, Wei; Wang, Jin; Huang, Li-Ke; Maple, Carsten; University of Bedfordshire; Aeroflex, Stevenage; Shanghai Jiao Tong University (IEEE, 2014-02)
      Direct conversion transmitters are widely used in wireless systems for their inherent features of being simple and low cost. In this architecture, the inphase (I branch) and quadrature signal (Q branch) will be unconverted to the RF frequency band by quadrature modulation. However, the drawback of the direct conversion architecture is that it is sensitive to IQ imbalance caused by the impairment of analogue devices in I and Q branches. It then results in interferences in mirror frequencies which degrades the signal quality. Therefore, the accurate measurement of IQ imbalance is crucial. A diode-based method to measure the broadband IQ imbalance is proposed which does not need additional measurement instruments. Measurement results show the effectiveness of this method
    • Distributed pixel mapping for refining dark area in parallax barriers based holoscopic 3D Display

      Swash, M.R.; Aggoun, Amar; Fatah, O. Abdul; Fernandez, Juan C. J.; Alazawi, E.; Tsekleves, Emmanuel; Brunel University; University of Bedfordshire (IEEE, 2013-12)
      Autostereoscopic 3D Display is robustly developed and available in the market for both home and professional users. However 3D resolution with acceptable 3D image quality remains a great challenge. This paper proposes a novel pixel mapping method for refining dark areas between two pinholes by distributing it into 3 times smaller dark areas and creating micro-pinholes in parallax barriers based holoscopic 3D displays. The proposed method allows to project RED, GREEN, BLUE subpixels separately from 3 different pinholes and it distributes the dark spaces into 3 times smaller dark spaces, which become unnoticeable and improves quality of the constructed holoscopic 3D scene significantly. Parallax barrier technology refers to a pinhole sheet or device placed in front or back of a liquid crystal display, allowing to project viewpoint pixels into space that reconstructs a holoscopic 3D scene in space. The holoscopic technology mimics the imaging system of insects, such as the fly, utilizing a single camera, equipped with a large number of micro-lenses or pinholes, to capture a scene, offering rich parallax information and enhanced 3D feeling without the need of wearing specific eyewear.
    • 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.
    • 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.
    • 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, 2014-09-15)
      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.
    • Editorial

      Kohl, Peter; Coveney, Peter V.; Clapworthy, Gordon J.; Viceconti, Marco (Royal Society Publishing, 2008-09)
      The second issue of Phil. Trans. R. Soc. A, devoted to ‘The virtual physiological human’, highlights the challenges involved in organ-level modelling of biological systems.
    • Editorial

      Clapworthy, Gordon J.; Viceconti, Marco; Coveney, Peter V.; Kohl, Peter (Royal Society Publishing, 2008-09)
    • Enabling the interactive display of large medical volume datasets by multiresolution bricking

      Agrawal, Anupam; Kohout, Josef; Clapworthy, Gordon J.; McFarlane, Nigel J.B.; Dong, Feng; Viceconti, Marco; Taddei, Fulvia; Testi, Debora (SpringerLink, 2010)
    • Energy-saving MAC protocols for Point-Controlled Wireless Networks: Best-Effort, QoS

      Safdar, Ghazanfar Ali (VDM Verlag, 2010)
      As wireless networks become an integral component of the modern communication infrastructure, energy efficiency will be an important design consideration due to the limited battery life of mobile and portable terminals. Such devices must operate with the highest possible energy efficiency while still maintaining a minimum quality of service to meet the user?s expectations. PCSAR, a new power-saving MAC protocol for centralized control wireless networks is presented in this book. The book contains power saving techniques employed by standards for WPAN and WLANs, such as Bluetooth, Zigbee, HiperLan, and IEEE 802.11. The steady state performance of PCSAR was compared with IEEE 802.11b power saving mode (PCF-PS) using DES of a typical WLAN scenario. To account for effect of errors on performance, PCSAR was also compared with PCF-PS for both uncorrelated and time-correlated channel models. Finally, PCSAR was modified to suit a QoS enabled MAC such as IEEE 802.11e. This book should be useful for professionals both in academics and industry, in the field of wireless communications and networking, especially those engaged in the development of MAC protocols for wireless networks
    • 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.
    • The EuroPhysiome, STEP and a roadmap for the virtual physiological human

      Fenner, J.W; Brook, B.; Clapworthy, Gordon J.; Coveney, Peter V.; Feipel, V.; Gregersen, H.; Hose, D.R.; Kohl, Peter; Lawford, Patricia; McCormack, K.M.; et al. (The Royal Society, 2008-09)
    • Evaluation of a statistical model for the characterization of multipath affecting mobile terminal GPS antennas in sub-urban areas

      Ur-Rehman, Masood; Chen, Xiaodong; Parini, Clive G.; Ying, Zhinong (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2012-02)
      This paper describes and validates a technique to characterize the environmental effects on mobile terminal GPS antennas using statistical model. This method requires the knowledge of 3-D free space antenna gain patterns and average angular distribution of incident power in the environment. The power distribution must be known in both elevation and azimuth and separately for parallel and perpendicular polarizations. The antenna performance is assessed in terms of GPS Mean Effective Gain (MEGGPS) and GPS Coverage Efficiency (ηc). Angle of Arrival (AoAGPS) distributions of incident GPS radio waves arriving at the mobile terminal are assumed to be randomly uniform in both the azimuth and elevation planes. It effectively replicates the open field (sub-urban) working conditions for the mobile terminal GPS antennas. The method could be adapted to an urban environment by introducing the information of AoAGPS distributions. A lengthy open field measurement campaign based on received signal-to-noise ratio (SNR) and mean number of tracked GPS satellites is carried out to validate the statistical model.