119 research outputs found
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Efficient FPGA implementation and power modelling of image and signal processing IP cores
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Field Programmable Gate Arrays (FPGAs) are the technology of choice in a number ofimage
and signal processing application areas such as consumer electronics, instrumentation,
medical data processing and avionics due to their reasonable energy consumption, high performance, security, low design-turnaround time and reconfigurability. Low power FPGA
devices are also emerging as competitive solutions for mobile and thermally constrained platforms. Most computationally intensive image and signal processing algorithms also consume a lot of power leading to a number of issues including reduced mobility, reliability concerns and increased design cost among others. Power dissipation has become one of the most important challenges, particularly for FPGAs. Addressing this problem requires optimisation and awareness at all levels in the design flow. The key achievements of the
work presented in this thesis are summarised here. Behavioural level optimisation strategies have been used for implementing matrix product and inner product through the use of mathematical techniques such as Distributed Arithmetic (DA) and its variations including offset binary coding, sparse factorisation and novel vector level transformations. Applications to test the impact of these algorithmic and arithmetic transformations include the fast Hadamard/Walsh transforms and Gaussian mixture models. Complete design space exploration has been performed on these cores, and where appropriate, they have been shown to clearly outperform comparable existing implementations. At the architectural level, strategies such as parallelism, pipelining and systolisation have been successfully applied for the design and optimisation of a number of
cores including colour space conversion, finite Radon transform, finite ridgelet transform and circular convolution. A pioneering study into the influence of supply voltage scaling for FPGA based designs, used in conjunction with performance enhancing strategies such as parallelism and pipelining has been performed. Initial results are very promising and indicated significant potential for future research in this area.
A key contribution of this work includes the development of a novel high level power macromodelling technique for design space exploration and characterisation of custom IP cores for FPGAs, called Functional Level Power Analysis and Modelling (FLPAM). FLPAM
is scalable, platform independent and compares favourably with existing approaches. A hybrid, top-down design flow paradigm integrating FLPAM with commercially available design tools for systematic optimisation of IP cores has also been developed
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Extraction of anthropological data with ultrasound
This thesis was submitted for the degree of Doctor of Philosophy and was awarded by Brunel University.Human body scanners used to extract anthropological data have a significant drawback, the
subject is required to undress or wear tight fitting clothing. This thesis demonstrates an
ultrasonic based alternative to the current optical systems, that can potentially operate on a fully
clothed subject. To validate the concept several experiments were performed to determine the
acoustic properties of multiple garments. The results indicated that such an approach was
possible.
Beamforming is introduced as a method by which the ultrasonic scanning area can be increased,
the concept is thoroughly studied and a clear theoretical analysis is performed. Additionally,
Matlab has been used to demonstrate graphically, the results of such analysis, providing an
invaluable tool during the simulation, experimental and results stages of the thesis.
To evaluate beamfoming as a composite part of ultrasonic body imaging, a hardware solution
was necessary. During the concept phase, both FPGA and digital signal processors were
evaluated to determine their suitability for the role. An FPGA approach was finally chosen,
which allows highly parallel operation, essential to the high acquisition speeds required by some
beamforming methodologies. In addition, analogue circuitry was also designed to provide an
interface with the ultrasonic transducers, which, included variable gain amplifiers, charge
amplifiers and signal conditioning. Finally, a digital acquisition card was used to transfer data
between the FPGA and a desktop computer, on which, the sampled data was processed and
displayed in a coherent graphical manner.
The beamforming results clearly demonstrate that imaging multiple layers in air, with
ultrasound, is a viable technique for anthroplogical data collection. Furthermore, a wavelet
based method of improving the axial resolution is also proposed and demonstrated
Interactions of fluorophores with complex surfaces and spectroscopic examinations of ancient manuscripts
In the first part of this thesis, it was found by fibre-optic fluorescence spectroscopy, that the greening of fabrics washed in optical brighteners is due to a reabsorption effect. The quantum yield of fluorescence of the optical brighteners OB15, OB36 and OB49 in water are , and respectively. Their respective fluorescence natural lifetimes are , and ps. In solution, the excited state of OB15 experiences more competing relaxation processes as the solvatochromic shift increases. OB49 displays the opposite trend.
A literature cellulose model surface is employed as a cotton mimic for evanescent wave fluorescence studies. Two model greases are similarly developed and used, and a third is presented for future work. These are based on surface-specific reactions with glass substrates, and the doping of a regenerated cellulose film with long chain alcohols. On doped cellulose surfaces, some low quantum yields occur compared to clean cellulose and bulk solution. Photobleaching behaviours are also observed. Both dyes physisorb rigidly to cellulose and grease models.
The second part of this thesis identifies the pigment palette of the earliest Northumbrian manuscripts pre- and post-1066, by Raman and diffuse reflectance spectroscopy. It develops a suite of multispectral imaging programs in MATLAB for facile classification of pigments across a page ab initio, using data reduction and colour spaces.
Raman and reflectance data are meta-analysed using symmetric permutation to split manuscripts and pigments into groups ab initio. It was also generalised, that the palette of the pre-Hastings selected manuscripts contained vergaut, indigo, orpiment, impure red lead, and copper green pigments, as well as orcein purples. Immediately post-1066 white lead, red ochre, vermilion and lapis lazuli appear in the palette in England, though vergaut and indigo disappear and the red lead used is essentially pure
Blind Source Separation for the Processing of Contact-Less Biosignals
(Spatio-temporale) Blind Source Separation (BSS) eignet sich für die Verarbeitung von Multikanal-Messungen im Bereich der kontaktlosen Biosignalerfassung. Ziel der BSS ist dabei die Trennung von (z.B. kardialen) Nutzsignalen und Störsignalen typisch für die kontaktlosen Messtechniken. Das Potential der BSS kann praktisch nur ausgeschöpft werden, wenn (1) ein geeignetes BSS-Modell verwendet wird, welches der Komplexität der Multikanal-Messung gerecht wird und (2) die unbestimmte Permutation unter den BSS-Ausgangssignalen gelöst wird, d.h. das Nutzsignal praktisch automatisiert identifiziert werden kann. Die vorliegende Arbeit entwirft ein Framework, mit dessen Hilfe die Effizienz von BSS-Algorithmen im Kontext des kamera-basierten Photoplethysmogramms bewertet werden kann. Empfehlungen zur Auswahl bestimmter Algorithmen im Zusammenhang mit spezifischen Signal-Charakteristiken werden abgeleitet. Außerdem werden im Rahmen der Arbeit Konzepte für die automatisierte Kanalauswahl nach BSS im Bereich der kontaktlosen Messung des Elektrokardiogramms entwickelt und bewertet. Neuartige Algorithmen basierend auf Sparse Coding erwiesen sich dabei als besonders effizient im Vergleich zu Standard-Methoden.(Spatio-temporal) Blind Source Separation (BSS) provides a large potential to process distorted multichannel biosignal measurements in the context of novel contact-less recording techniques for separating distortions from the cardiac signal of interest. This potential can only be practically utilized (1) if a BSS model is applied that matches the complexity of the measurement, i.e. the signal mixture and (2) if permutation indeterminacy is solved among the BSS output components, i.e the component of interest can be practically selected. The present work, first, designs a framework to assess the efficacy of BSS algorithms in the context of the camera-based photoplethysmogram (cbPPG) and characterizes multiple BSS algorithms, accordingly. Algorithm selection recommendations for certain mixture characteristics are derived. Second, the present work develops and evaluates concepts to solve permutation indeterminacy for BSS outputs of contact-less electrocardiogram (ECG) recordings. The novel approach based on sparse coding is shown to outperform the existing concepts of higher order moments and frequency-domain features
Digital Signal Processor Based Real-Time Phased Array Radar Backend System and Optimization Algorithms
This dissertation presents an implementation of multifunctional large-scale phased array radar based on the scalable DSP platform.
The challenge of building large-scale phased array radar backend is how to address the compute-intensive operations and high data throughput requirement in both front-end and backend in real-time. In most of the applications, FPGA or VLSI hardware are typically used to solve those difficulties. However, with the help of the fast development of IC industry, using a parallel set of high-performing programmable chips can be an alternative. We present a hybrid high-performance backend system by using DSP as the core computing device and MTCA as the system frame. Thus, the mapping techniques for the front and backend signal processing algorithm based on DSP are discussed in depth.
Beside high-efficiency computing device, the system architecture would be a major factor influencing the reliability and performance of the backend system. The reliability requires the system must incorporate the redundancy both in hardware and software. In this dissertation, we propose a parallel modular system based on MTCA chassis, which can be reliable, scalable, and fault-tolerant.
Finally, we present an example of high performance phased array radar backend, in which there is the number of 220 DSPs, achieving 7000 GFLOPS calculation from 768 channels. This example shows the potential of using the combination of DSP and MTCA as the computing platform for the future multi-functional large-scale phased array radar
Técnicas de compresión de imágenes hiperespectrales sobre hardware reconfigurable
Tesis de la Universidad Complutense de Madrid, Facultad de Informática, leĂda el 18-12-2020Sensors are nowadays in all aspects of human life. When possible, sensors are used remotely. This is less intrusive, avoids interferces in the measuring process, and more convenient for the scientist. One of the most recurrent concerns in the last decades has been sustainability of the planet, and how the changes it is facing can be monitored. Remote sensing of the earth has seen an explosion in activity, with satellites now being launched on a weekly basis to perform remote analysis of the earth, and planes surveying vast areas for closer analysis...Los sensores aparecen hoy en dĂa en todos los aspectos de nuestra vida. Cuando es posible, de manera remota. Esto es menos intrusivo, evita interferencias en el proceso de medida, y además facilita el trabajo cientĂfico. Una de las preocupaciones recurrentes en las Ăşltimas dĂ©cadas ha sido la sotenibilidad del planeta, y cĂłmo menitoirzar los cambios a los que se enfrenta. Los estudios remotos de la tierra han visto un gran crecimiento, con satĂ©lites lanzados semanalmente para analizar la superficie, y aviones sobrevolando grades áreas para análisis más precisos...Fac. de InformáticaTRUEunpu
Design for prognostics and security in field programmable gate arrays (FPGAs).
There is an evolutionary progression of Field Programmable Gate Arrays (FPGAs)
toward more complex and high power density architectures such as Systems-on-
Chip (SoC) and Adaptive Compute Acceleration Platforms (ACAP). Primarily, this is
attributable to the continual transistor miniaturisation and more innovative and
efficient IC manufacturing processes. Concurrently, degradation mechanism of Bias
Temperature Instability (BTI) has become more pronounced with respect to its
ageing impact. It could weaken the reliability of VLSI devices, FPGAs in particular
due to their run-time reconfigurability. At the same time, vulnerability of FPGAs to
device-level attacks in the increasing cyber and hardware threat environment is also
quadrupling as the susceptible reliability realm opens door for the rogue elements to
intervene. Insertion of highly stealthy and malicious circuitry, called hardware
Trojans, in FPGAs is one of such malicious interventions. On the one hand where
such attacks/interventions adversely affect the security ambit of these devices, they
also undermine their reliability substantially. Hitherto, the security and reliability are
treated as two separate entities impacting the FPGA health. This has resulted in
fragmented solutions that do not reflect the true state of the FPGA operational and
functional readiness, thereby making them even more prone to hardware attacks.
The recent episodes of Spectre and Meltdown vulnerabilities are some of the key
examples. This research addresses these concerns by adopting an integrated
approach and investigating the FPGA security and reliability as two inter-dependent
entities with an additional dimension of health estimation/ prognostics. The design
and implementation of a small footprint frequency and threshold voltage-shift
detection sensor, a novel hardware Trojan, and an online transistor dynamic scaling
circuitry present a viable FPGA security scheme that helps build a strong
microarchitectural level defence against unscrupulous hardware attacks. Augmented
with an efficient Kernel-based learning technique for FPGA health
estimation/prognostics, the optimal integrated solution proves to be more
dependable and trustworthy than the prevalent disjointed approach.Samie, Mohammad (Associate)PhD in Transport System
Efficient FPGA implementation and power modelling of image and signal processing IP cores
Field Programmable Gate Arrays (FPGAs) are the technology of choice in a number ofimage and signal processing application areas such as consumer electronics, instrumentation, medical data processing and avionics due to their reasonable energy consumption, high performance, security, low design-turnaround time and reconfigurability. Low power FPGA devices are also emerging as competitive solutions for mobile and thermally constrained platforms. Most computationally intensive image and signal processing algorithms also consume a lot of power leading to a number of issues including reduced mobility, reliability concerns and increased design cost among others. Power dissipation has become one of the most important challenges, particularly for FPGAs. Addressing this problem requires optimisation and awareness at all levels in the design flow. The key achievements of the work presented in this thesis are summarised here. Behavioural level optimisation strategies have been used for implementing matrix product and inner product through the use of mathematical techniques such as Distributed Arithmetic (DA) and its variations including offset binary coding, sparse factorisation and novel vector level transformations. Applications to test the impact of these algorithmic and arithmetic transformations include the fast Hadamard/Walsh transforms and Gaussian mixture models. Complete design space exploration has been performed on these cores, and where appropriate, they have been shown to clearly outperform comparable existing implementations. At the architectural level, strategies such as parallelism, pipelining and systolisation have been successfully applied for the design and optimisation of a number of cores including colour space conversion, finite Radon transform, finite ridgelet transform and circular convolution. A pioneering study into the influence of supply voltage scaling for FPGA based designs, used in conjunction with performance enhancing strategies such as parallelism and pipelining has been performed. Initial results are very promising and indicated significant potential for future research in this area. A key contribution of this work includes the development of a novel high level power macromodelling technique for design space exploration and characterisation of custom IP cores for FPGAs, called Functional Level Power Analysis and Modelling (FLPAM). FLPAM is scalable, platform independent and compares favourably with existing approaches. A hybrid, top-down design flow paradigm integrating FLPAM with commercially available design tools for systematic optimisation of IP cores has also been developed.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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