Hardware implementations of computer-generated holography: a review

Computer-generated holography (CGH) is a technique to generate holographic interference patterns. One of the major issues related to computer hologram generation is the massive computational power required. Hardware accelerators are used to accelerate this process. Previous publications targeting hardware platforms lack performance comparisons between different architectures and do not provide enough information for the evaluation of the suitability of recent hardware platforms for CGH algorithms. We aim to address these limitations and present a comprehensive review of CGH-related hardware implementations

Smart video sensors for 3D scene reconstruction of large infrastructures

The final publication is available at Springer via http://dx.doi.org/10.1007/s11042-012-1184-zThis paper introduces a new 3D-based surveillance solution for large infrastructures. Our proposal is based on an accurate 3D reconstruction using the rich information obtained from a network of intelligent video-processing nodes. In this manner, if the scenario to cover is modeled in 3D with high precision, it will be possible to locate the detected objects in the virtual representation. Moreover, as an improvement over previous 2D solutions, having the possibility of modifying the view point enables the application to choose the perspective that better suits the current state of the scenario. In this sense, the contextualization of the events detected in a 3D environment can offer a much better understanding of what is happening in the real world and where it is exactly happening. Details of the video processing nodes are given, as well as of the 3D reconstruction tasks performed afterwards. The possibilities of such a system are described and the performance obtained is analyzed.This work has been partially supported by the ViCoMo project (ITEA2 project IP08009 funded by the Spanish MICINN with project TSI-020400-2011-57), the Spanish Government (TIN2009-14103-C03-03, DPI2008-06737-C02-01/02 and DPI 2011-28507-C02-02) and European FEDER funds.Ripollés Mateu, ÓE.; Simó Ten, JE.; Benet Gilabert, G.; Vivó Hernando, RA. (2014). Smart video sensors for 3D scene reconstruction of large infrastructures. Multimedia Tools and Applications. 73(2):977-993. https://doi.org/10.1007/s11042-012-1184-zS977993732Atienza-Vanacloig V, Rosell-Ortega J, Andreu-Garcia G, Valiente-Gonzalez J (2008) People and luggage recognition in airport surveillance under real-time constraints. In: 19th international conference on pattern recognition, pp 1–4Cal3D (2011) http://gna.org/projects/cal3d/ . Accessed 19 July 2012Chang F, Chen CJ (2003) A component-labeling algorithm using contour tracing technique. In: 7th int. conference on document analysis and recognition, pp 741–745Cruz-Neira C, Sandin DJ, DeFanti TA, Kenyon RV, Hart JC (1992) The cave: audio visual experience automatic virtual environment. Commun ACM 35:64–72Fleck S, Busch F, Biber P, Strasser W (2006) 3D surveillance a distributed network of smart cameras for real-time tracking and its visualization in 3D. In: Conference on computer vision and pattern recognition workshop (CVPRW06), p 118Hoiem D, Efros AA, Hebert M (2005) Automatic photo pop-up. ACM Trans Graph 24:577–584Javed O, Shah M (2008) Automated multi-camera surveillance: algorithms and practice. Springer, New YorkLipton A, Fujiyoshi H, Patil R (1998) Moving target classification and tracking from real-time video. In: Proceedings of IEEE workshop on applications of computer vision, vol 1, pp 8–14Lloyd DH (1968) A concept of improvement of learning response in the taught lesson. In: Visual education, pp 23–25Osfield R, Burns D (2011) OpenSceneGraph. http://www.openscenegraph.org . Accessed 19 July 2012Rieffel EG, Girgensohn A, Kimber D, Chen T, Liu Q (2007) Geometric tools for multicamera surveillance systems. In: IEEE int. conf. on distributed smart camerasSebe I, Hu J, You S, Neumann U (2003) 3D video surveillance with augmented virtual environments. In: ACM SIGMM workshop on video surveillance, pp 107–112SENSE Consortium (2006) Smart embedded network of sensing entities. Web page: http://www.sense-ist.org (European Commission: IST Project 033279). Accessed 19 July 2012Sánchez J, Benet G, Simó JE (2012) Video sensor architecture for surveillance applications. Sensors 12(2):1509–1528Vouzounaras G, Daras P, Strintzis M (2011) Automatic generation of 3D outdoor and indoor building scenes from a single image. Multimedia Tools Appl. doi: 10.1007/s11042-011-0823-0Yan W, Kieran D, Rafatirad S, Jain R (2011) A comprehensive study of visual event computing. Multimedia Tools Appl 55:443–481Zúñiga M, Brémond F, Thonnat M (2006) Fast and reliable object classification in video based on a 3D generic model. In: Proceedings of the international conference on visual information engineering (VIE2006), pp 26–2

Investigation into the use of zero angle ultrasonic probe array for defect detection and location

The steel industry like any other manufacturing process is under constant pressure to deliver higher quality defect free material at lower cost to customers. This push for zero defects has led to improved manufacturing processes and the need for more reliable, faster defect testing methods. Ultrasound fundamentally provides a mechanical stress, produced by tensile, compressive, shearing or flexural forces, which are of such low intensity that no material damage occurs. The remit of the project was to investigate and develop the latent potential within the Present automated ultrasonic immersion system using an array of normal angle probes, used for billet inspection. The work presented in this thesis describes the research undertaken to develop a system using, 10mm diameter, standard zero angled 5MHz ultrasonic transducers. The transducers were used at linear separation distances of between 22.5mm and 45mm set in a typical 8-probe array orientation. The developed technique is potentially transferable to other ultrasonic multi-probe array applications and demonstrates that time of flight diffraction can be realised using normal probes, and termed Normal Probe Diffraction, (NPD). The technique located defects, using the intersection of ellipses, with an error of <0.5% of the signal transit distance and, with the application of a correlation filter, improved the Signal to Noise Ratio (SNR) from—20dB to 17.0dB

Continuous Occupancy Mapping in Dynamic Environments Using Particles

Particle-based dynamic occupancy maps were proposed in recent years to model the obstacles in dynamic environments. Current particle-based maps describe the occupancy status in discrete grid form and suffer from the grid size problem, wherein a large grid size is unfavorable for motion planning, while a small grid size lowers efficiency and causes gaps and inconsistencies. To tackle this problem, this paper generalizes the particle-based map into continuous space and builds an efficient 3D egocentric local map. A dual-structure subspace division paradigm, composed of a voxel subspace division and a novel pyramid-like subspace division, is proposed to propagate particles and update the map efficiently with the consideration of occlusions. The occupancy status of an arbitrary point in the map space can then be estimated with the particles' weights. To further enhance the performance of simultaneously modeling static and dynamic obstacles and minimize noise, an initial velocity estimation approach and a mixture model are utilized. Experimental results show that our map can effectively and efficiently model both dynamic obstacles and static obstacles. Compared to the state-of-the-art grid-form particle-based map, our map enables continuous occupancy estimation and substantially improves the performance in different resolutions.Comment: This paper has been accepted by IEEE Transactions on Robotic

Performance Evaluation of Orthogonal Frequency Division Multiplexing using 16-bit Irregular Data Formats

This report asserts that 16-bit Digital Signal Processing applications suffer from dynamic range and noise performance issues. This problem is highly common in complex DSP algorithms and is compounded if they are programmed in high level languages due to no native compiler support for 16-bit data formats. A solution to this problem is achieved by using 16-bit irregular data formats which show significant improvement over fixed and floating point approaches. First, the data formatting problem for 16-bit programmable devices are defined and discussed. Existing solutions to the problem is taken into consideration. Then a new class of floating point numbers is obtained from which irregular data formats are derived. Attempts are made to derive format with greater dynamic range and noise performance. Then the irregular data format along with fixed and floating point formats are simulated and analysed for simple DSP applications to make a performance analysis. Finally the data formats under consideration are implemented in a full-fledged Orthogonal Frequency Division Multiplexing model. The inputs and outputs obtained are compared for the percentage of error and final conclusions are drawn. The results indicate that irregular data formats have significant improvement over fixed and floating point formats and 16-bit DSP applications can be implemented in a more effective way using irregular data formats

Image Processing Using FPGAs

This book presents a selection of papers representing current research on using field programmable gate arrays (FPGAs) for realising image processing algorithms. These papers are reprints of papers selected for a Special Issue of the Journal of Imaging on image processing using FPGAs. A diverse range of topics is covered, including parallel soft processors, memory management, image filters, segmentation, clustering, image analysis, and image compression. Applications include traffic sign recognition for autonomous driving, cell detection for histopathology, and video compression. Collectively, they represent the current state-of-the-art on image processing using FPGAs

Tools for efficient Deep Learning

In the era of Deep Learning (DL), there is a fast-growing demand for building and deploying Deep Neural Networks (DNNs) on various platforms. This thesis proposes five tools to address the challenges for designing DNNs that are efficient in time, in resources and in power consumption. We first present Aegis and SPGC to address the challenges in improving the memory efficiency of DL training and inference. Aegis makes mixed precision training (MPT) stabler by layer-wise gradient scaling. Empirical experiments show that Aegis can improve MPT accuracy by at most 4\%. SPGC focuses on structured pruning: replacing standard convolution with group convolution (GConv) to avoid irregular sparsity. SPGC formulates GConv pruning as a channel permutation problem and proposes a novel heuristic polynomial-time algorithm. Common DNNs pruned by SPGC have maximally 1\% higher accuracy than prior work. This thesis also addresses the challenges lying in the gap between DNN descriptions and executables by Polygeist for software and POLSCA for hardware. Many novel techniques, e.g. statement splitting and memory partitioning, are explored and used to expand polyhedral optimisation. Polygeist can speed up software execution in sequential and parallel by 2.53 and 9.47 times on Polybench/C. POLSCA achieves 1.5 times speedup over hardware designs directly generated from high-level synthesis on Polybench/C. Moreover, this thesis presents Deacon, a framework that generates FPGA-based DNN accelerators of streaming architectures with advanced pipelining techniques to address the challenges from heterogeneous convolution and residual connections. Deacon provides fine-grained pipelining, graph-level optimisation, and heuristic exploration by graph colouring. Compared with prior designs, Deacon shows resource/power consumption efficiency improvement of 1.2x/3.5x for MobileNets and 1.0x/2.8x for SqueezeNets. All these tools are open source, some of which have already gained public engagement. We believe they can make efficient deep learning applications easier to build and deploy.Open Acces