• 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.
    • 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.
    • Performance simulations of moving target search algorithms

      Loh, Peter K. K.; Prakash, Edmond C. (Hindawi, 2009)
      The design of appropriate moving target search (MTS) algorithms for computer-generated bots poses serious challenges as they have to satisfy stringent requirements that include computation and execution efficiency. In this paper, we investigate the performance and behaviour of existing moving target search algorithms when applied to search-and-capture gaming scenarios. As part of the investigation, we also introduce a novel algorithm known as abstraction MTS. We conduct performance simulations with a game bot and moving target within randomly generated mazes of increasing sizes and reveal that abstraction MTS exhibits competitive performance even with large problem spaces.
    • Pre-processing of holoscopic 3D image for autostereoscopic 3D displays

      Swash, M.R.; Aggoun, Amar; Fatah, O. Abdul; Li, B.; Fernandez, Juan C. J.; Alazawi, E.; Tsekleves, Emmanuel; University of Bedfordshire; Brunel University (2013-12)
      Holoscopic 3D imaging also known as Integral imaging is an attractive technique for creating full colour 3D optical models that exist in space independently of the viewer. The constructed 3D scene exhibits 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 microlens arrays, which view the scene at a slightly different angle to its neighbour. However, the main problem is that the microlens array introduces a dark borders in the recorded image and this causes errors at playback on the holoscopic 3D Display. This paper proposes a reference based pre-processing of holoscopic 3D image for autostereoscopic holoscopic 3D displays. The proposed method takes advantages of microlens as reference point to detect amount of introduced dark borders and reduce/remove them from the holoscopic 3D image.
    • 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.
    • 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.
    • 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.
    • 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.
    • Rendering of novel views from photographs using inference in Markov random field

      Dong, Feng; Clapworthy, Gordon J.; Lin, Hai (IET, 2009-12-03)
    • RESTful web service composition: extracting a process model from Linear Logic theorem proving

      Zhao, Xia; Liu, Enjie; Clapworthy, Gordon J.; Ye, Na; Lu, Yueming (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2011-10)
    • 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.
    • Scene depth extraction from Holoscopic Imaging technology

      Alazawi, E.; Aggoun, Amar; Abbod, M.; Swash, M.R.; Abdul Fatah, O.; Fernandez, Juan C. J.; University of Bedfordshire; Brunel University (IEEE, 2013-10)
      3D Holoscopic Imaging (3DHI) is a promising technique for viewing natural continuous parallax 3D objects within a wide viewing zone using the principle of “Fly's eye”. The 3D content is captured using a single aperture camera in real-time and represents a true volume spatial optical model of the object scene. The 3D content viewed by multiple viewers independently of their position, without 3D eyewear glasses. The 3DHI technique merely requires a single recording that the acquisition of the 3D information and the compactness of depth measurement that is used has been attracting attention as a novel depth extraction technique. This paper presents a new corresponding and matching technique based on a novel automatic Feature-Match Selection (FMS) algorithm. The aim of this algorithm is to estimate and extract an accurate full parallax 3D model form from a 3D Omni-directional Holoscopic Imaging (3DOHI) system. The basis for the novelty of the paper is on two contributions: feature blocks selection and corresponding automatic optimization process. There are solutions for three main problems related to the depth map estimation from 3DHI: uncertainty and region homogeneity at image location, dissimilar displacements within the matching block around object borders, and computational complexity.
    • Scheduling and optimisation of batch plants: model development and comparison of approaches

      Tan, Yaqing; Huang, Wei; Sun, Yanming; Yue, Yong; University of Bedfordshire (Inderscience Publishers, 2014-06)
      The application of parallel machines and storage facilities provides flexibility but raises challenges for batch plants. This research proposes a scheduling model in batch plants, considering complex real-world constraints that were seldom addressed together. Two optimisation approaches, genetic algorithm (GA) and constraint programming (CP), are applied to solve the complex batch plant scheduling problem. A case study and scalability tests are conducted to investigate different performance of GA and CP in the problem to prepare for further research application. It is found that the CP approach has a better performance in solving batch plant scheduling problems with complex constraints although it needs longer time. The ‘restart’ search strategy is better than two other search strategies for the CP approach.
    • Semi-supervised tissue segmentation of 3D brain MR images

      Zhang, Xiangrong; Dong, Feng; Clapworthy, Gordon J.; Zhao, Youbing; Jiao, Licheng (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2010)
    • Shape-enhanced maximum intensity projection

      Zhou, Zhiguang; Tao, Yubo; Lin, Hai; Dong, Feng; Clapworthy, Gordon J. (SpringerLink, 2011)
      Maximum intensity projection (MIP) displays the voxel with the maximum intensity along the viewing ray, and this offers simplicity in usage, as it does not require a complex transfer function, the specification of which is a highly challenging and time-consuming process in direct volume rendering (DVR). However, MIP also has its inherent limitation, the loss of spatial context and shape information. This paper proposes a novel technique, shape-enhanced maximum intensity projection (SEMIP), to resolve this limitation. Inspired by lighting in DVR to emphasize surface structures, SEMIP searches a valid gradient for the maximum intensity of each viewing ray, and applies gradient-based shading to improve shape and depth perception of structures. As SEMIP may result in the pixel values over the maximum intensity of the display device, a tone reduction technique is introduced to compress the intensity range of the rendered image while preserving the original local contrast. In addition, depth-based color cues are employed to enhance the visual perception of internal structures, and a focus and context interaction is used to highlight structures of interest. We demonstrate the effectiveness of the proposed SEMIP with several volume data sets, especially from the medical field.
    • Single feed stacked patch circular polarized antenna for triple band GPS receivers

      Falade, Oluyemi Peter; Ur-Rehman, Masood; Gao, Yue; Chen, Xiaodong; Parini, Clive G.; Queen Mary University, London (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2012-10)
      A novel design of a circular polarized antenna for multiband GPS receivers is presented. The design employs the concept of multistacked patches fed through a single coaxial probe. Three patches being stacked together with a slit and symmetry I-slot are used to achieve triple operating frequency bands for GPS including L1 (1.575 GHz), L2 (1.227 GHz) and L5 (1.176 GHz). The proposed antenna has achieved a bandwidth of 2.0%, 1.5%, and 1.7% at GPS L1, L2, and L5 bands, respectively. It exhibits a minimum axial ratio of 0.51 dB with broad beamwidth in the upper hemisphere required for the GPS applications. The design of the proposed antenna is verified in the experiment. In addition, a detailed analysis has been carried out to study the effects of different geometrical parameters on the performance of the antenna.
    • SOA-based digital library services and composition in biomedical applications

      Zhao, Xia; Liu, Enjie; Clapworthy, Gordon J.; Viceconti, Marco; Testi, Debora (Elsevier, 2012-06)
    • Strategic team AI path plans: probabilistic pathfinding

      John, Tng C. H.; Prakash, Edmond C.; Chaudhari, Narendra S. (Hindawi, 2008)
      This paper proposes a novel method to generate strategic team AI pathfinding plans for computer games and simulations using probabilistic pathfinding. This method is inspired by genetic algorithms (Russell and Norvig, 2002), in that, a fitness function is used to test the quality of the path plans. The method generates high-quality path plans by eliminating the low-quality ones. The path plans are generated by probabilistic pathfinding, and the elimination is done by a fitness test of the path plans. This path plan generation method has the ability to generate variation or different high-quality paths, which is desired for games to increase replay values. This work is an extension of our earlier work on team AI: probabilistic pathfinding (John et al., 2006). We explore ways to combine probabilistic pathfinding and genetic algorithm to create a new method to generate strategic team AI pathfinding plans.