Accelerating Gauss-Newton filters on FPGA's

Includes bibliographical references (leaves 123-128).Radar tracking filters are generally computationally expensive, involving the manipulation of large matrices and deeply nested loops. In addition, they must generally work in real-time to be of any use. The now-common Kalman Filter was developed in the 1960's specifically for the purposes of lowering its computational burden, so that it could be implemented using the limited computational resources of the time. However, with the exponential increases in computing power since then, it is now possible to reconsider more heavy-weight, robust algorithms such as the original nonrecursive Gauss-Newton filter on which the Kalman filter is based. This dissertation investigates the acceleration of such a filter using FPGA technology, making use of custom, reduced-precision number formats

Benchmark for Peak Detection Algorithms in Fiber Bragg Grating Interrogation and a New Neural Network for its Performance Improvement

This paper presents a benchmark for peak detection algorithms employed in fiber Bragg grating spectrometric interrogation systems. The accuracy, precision, and computational performance of currently used algorithms and those of a new proposed artificial neural network algorithm are compared. Centroid and gaussian fitting algorithms are shown to have the highest precision but produce systematic errors that depend on the FBG refractive index modulation profile. The proposed neural network displays relatively good precision with reduced systematic errors and improved computational performance when compared to other networks. Additionally, suitable algorithms may be chosen with the general guidelines presented

Design of a reusable distributed arithmetic filter and its application to the affine projection algorithm

Digital signal processing (DSP) is widely used in many applications spanning the spectrum from audio processing to image and video processing to radar and sonar processing. At the core of digital signal processing applications is the digital filter which are implemented in two ways, using either finite impulse response (FIR) filters or infinite impulse response (IIR) filters. The primary difference between FIR and IIR is that for FIR filters, the output is dependent only on the inputs, while for IIR filters the output is dependent on the inputs and the previous outputs. FIR filters also do not sur from stability issues stemming from the feedback of the output to the input that aect IIR filters. In this thesis, an architecture for FIR filtering based on distributed arithmetic is presented. The proposed architecture has the ability to implement large FIR filters using minimal hardware and at the same time is able to complete the FIR filtering operation in minimal amount of time and delay when compared to typical FIR filter implementations. The proposed architecture is then used to implement the fast affine projection adaptive algorithm, an algorithm that is typically used with large filter sizes. The fast affine projection algorithm has a high computational burden that limits the throughput, which in turn restricts the number of applications. However, using the proposed FIR filtering architecture, the limitations on throughput are removed. The implementation of the fast affine projection adaptive algorithm using distributed arithmetic is unique to this thesis. The constructed adaptive filter shares all the benefits of the proposed FIR filter: low hardware requirements, high speed, and minimal delay.Ph.D.Committee Chair: Anderson, Dr. David V.; Committee Member: Hasler, Dr. Paul E.; Committee Member: Mooney, Dr. Vincent J.; Committee Member: Taylor, Dr. David G.; Committee Member: Vuduc, Dr. Richar

ワイヤレス通信のための先進的な信号処理技術を用いた非線形補償法の研究

The inherit nonlinearity in analogue front-ends of transmitters and receivers have had primary impact on the overall performance of the wireless communication systems, as it gives arise of substantial distortion when transmitting and processing signals with such circuits. Therefore, the nonlinear compensation (linearization) techniques become essential to suppress the distortion to an acceptable extent in order to ensure sufficient low bit error rate. Furthermore, the increasing demands on higher data rate and ubiquitous interoperability between various multi-coverage protocols are two of the most important features of the contemporary communication system. The former demand pushes the communication system to use wider bandwidth and the latter one brings up severe coexistence problems. Having fully considered the problems raised above, the work in this Ph.D. thesis carries out extensive researches on the nonlinear compensations utilizing advanced digital signal processing techniques. The motivation behind this is to push more processing tasks to the digital domain, as it can potentially cut down the bill of materials (BOM) costs paid for the off-chip devices and reduce practical implementation difficulties. The work here is carried out using three approaches: numerical analysis & computer simulations; experimental tests using commercial instruments; actual implementation with FPGA. The primary contributions for this thesis are summarized as the following three points: 1) An adaptive digital predistortion (DPD) with fast convergence rate and low complexity for multi-carrier GSM system is presented. Albeit a legacy system, the GSM, however, has a very strict requirement on the out-of-band emission, thus it represents a much more difficult hurdle for DPD application. It is successfully implemented in an FPGA without using any other auxiliary processor. A simplified multiplier-free NLMS algorithm, especially suitable for FPGA implementation, for fast adapting the LUT is proposed. Many design methodologies and practical implementation issues are discussed in details. Experimental results have shown that the DPD performed robustly when it is involved in the multichannel transmitter. 2) The next generation system (5G) will unquestionably use wider bandwidth to support higher throughput, which poses stringent needs for using high-speed data converters. Herein the analog-to-digital converter (ADC) tends to be the most expensive single device in the whole transmitter/receiver systems. Therefore, conventional DPD utilizing high-speed ADC becomes unaffordable, especially for small base stations (micro, pico and femto). A digital predistortion technique utilizing spectral extrapolation is proposed in this thesis, wherein with band-limited feedback signal, the requirement on ADC speed can be significantly released. Experimental results have validated the feasibility of the proposed technique for coping with band-limited feedback signal. It has been shown that adequate linearization performance can be achieved even if the acquisition bandwidth is less than the original signal bandwidth. The experimental results obtained by using LTE-Advanced signal of 320 MHz bandwidth are quite satisfactory, and to the authors’ knowledge, this is the first high-performance wideband DPD ever been reported. 3) To address the predicament that mobile operators do not have enough contiguous usable bandwidth, carrier aggregation (CA) technique is developed and imported into 4G LTE-Advanced. This pushes the utilization of concurrent dual-band transmitter/receiver, which reduces the hardware expense by using a single front-end. Compensation techniques for the respective concurrent dual-band transmitter and receiver front-ends are proposed to combat the inter-band modulation distortion, and simultaneously reduce the distortion for the both lower-side band and upper-side band signals.電気通信大学201

Performance Comparison of 3D Sinc Interpolation for fMRI Motion Correction by Language of Implementation and Hardware Platform

Substantial effort is devoted to improving neuroimaging data processing; this effort however, is typically from the algorithmic perspective only. I demonstrate that substantive running time performance improvements to neuroscientific data processing algorithms can be realized by considering their implementation. Focusing specifically on 3D sinc interpolation, an algorithm used for processing functional magnetic resonance imaging (fMRI) data, I compare the performance of Python, C and OpenCL implementations of this algorithm across multiple hardware platforms. I also benchmark the performance of a novel implementation of 3D sinc interpolation on a field programmable gate array (FPGA). Together, these comparisons demonstrate that the performance of a neuroimaging data processing algorithm is significantly impacted by its implementation. I also present a case study demonstrating the practical benefits of improving a neuroscientific data processing algorithm\u27s implementation, then conclude by addressing threats to the validity of the study and discussing future directions

Electrical Impedance Tomography/Spectroscopy (EITS): a Code Division Multiplexed (CDM) approach

Electrical Impedance Tomography and Spectroscopy (EITS) is a noninvasive imaging technique that creates images of cross-sections "tomos" of objects by discriminating them based on their electrical impedance. This thesis investigated and successfully confirmed the use of Code Division Multiplexing (CDM) using Gold codes in Electrical Impedance Tomography and Spectroscopy. The results obtained showed 3.5% and 6.2% errors in determining the position and size of imaged anomalies respectively, with attainable imaging speed of 462 frames/second. These results are better, compared to those reported when using Time Division Multiplexing (TDM) and Frequency Division Multiplexing (FDM).This new approach provides a more robust mode of EITS for fast changing dynamic systems by eliminating temporal data inconsistencies. Furthermore, it enables robust use of frequency difference imaging and spectroscopy in EITS by eliminating frequency data inconsistencies. In this method of imaging, electric current patterns are safely injected into the imaged object by a set of electrodes arranged in a single plane on the objects surface, for 2-Dimensional (2D) imaging. For 3-Dimensional (3D) imaging, more electrode planes are used on the objects surface. The injected currents result in measurable voltages on the objects surface. Such voltages are measured, and together with the input currents, and a Finite Element Model (FEM) of the object, used to reconstruct an impedance image of the cross-sectional contents of the imaged object. The reconstruction process involves the numerical solutions of the forward problem; using Finite Element solvers and the resulting ill-posed inverse problem using iterative Optimization or Computational Intelligence methods. This method has applications mainly in the Biomedical imaging and Process monitoring fields. The primary interests of the author are, in imaging and diagnosis of cancer, neonatal pneumonia and neurological disorders which are leading causes of death in Africa and world-wide

書き換え可能なゲートアレイを用いた無作為抽出法に基づく実時間画像処理に関する研究

長崎大学学位論文 学位記番号:博(工)甲第53号 学位授与年月日:平成30年3月20日Nagasaki University (長崎大学)課程博

Sensor Signal and Information Processing II

In the current age of information explosion, newly invented technological sensors and software are now tightly integrated with our everyday lives. Many sensor processing algorithms have incorporated some forms of computational intelligence as part of their core framework in problem solving. These algorithms have the capacity to generalize and discover knowledge for themselves and learn new information whenever unseen data are captured. The primary aim of sensor processing is to develop techniques to interpret, understand, and act on information contained in the data. The interest of this book is in developing intelligent signal processing in order to pave the way for smart sensors. This involves mathematical advancement of nonlinear signal processing theory and its applications that extend far beyond traditional techniques. It bridges the boundary between theory and application, developing novel theoretically inspired methodologies targeting both longstanding and emergent signal processing applications. The topic ranges from phishing detection to integration of terrestrial laser scanning, and from fault diagnosis to bio-inspiring filtering. The book will appeal to established practitioners, along with researchers and students in the emerging field of smart sensors processing

FPGA prototype for wavefront reconstruction acceleration

La óptica adaptativa es una tecnología usada para mejorar el rendimiento de diferentes tipos de sistemas ópticos. Lo hace corrigiendo las posibles aberraciones que son introducidas por la atmósfera. Para corregirlo se usa un sensor de frente de onda, habitualmente un Shack-Hartmann. En esta técnica, hasta centenas de centroides de imágenes deben ser calculados. De este modo el frente de onda original puede ser reconstruido. La óptica adaptativa impone restricciones temporales muy acusadas, el proceso completo debe ser realizado en un tiempo del orden de un milisegundo. Debido a esta limitación los algoritmos usados para calcular cada centroide son rápidos, pero normalmente su precisión es baja. En la misión Gaia de la ESA se ha desarrollado un algoritmo de cálculo de centroides de máxima verosimilitud, teniendo el mismo una precisión muy cercana al máximo teórico, la cota inferior de Crámer-Rao. Como este algoritmo es computacionalmente complejo, es normalmente demasiado lento para se usado en óptica adaptativa. Una versión simplificada que usa look-up tables fue desarrollada para estudiar si esta podría cumplir los requisitos temporales. En un trabajo previo, una primera versión de un sistema basado en FPGA que implementa este algoritmo fue creada. Consiste en un sistema empotrado que usa un procesador soft Microblaze para controlar un sistema con un coprocesador. Este coprocesador fue creado usando herramientas de síntesis de alto nivel, lo que se probó adecuado para implementar algoritmos intensivos en el cálculo con datos. Este prototipo tenía una funcionalidad reducida, y estaba seriamente limitado. El tamaño de la tabla usada era demasiado pequeño, y sólo realizaba una iteración del algoritmo de cálculo de centroides. En este proyecto se presenta una versión más completa de este prototipo, así como un estudio de la precisión alcanzada por tabla de diferentes tamaños y un estudio de la convergencia del algoritmo. Además, se compara la precisión de algoritmo ya implementado con el mismo en una plataforma software. La aceleración del algoritmo ha sido medida y un estudio multinúcleo ha sido realizado.Adaptive optics is a technology used to improve the performance of different kinds of optical systems. It does so correcting the possible aberrations that are introduced by the atmosphere. To correct it, a wave front sensor is used, often a Shack-Hartmann. In this technique, up to hundreds of image centroids have to be determined. In this way the original wave front can be reconstructed. Adaptive optics imposes a very restrictive time constraint, the whole process must be completed in a time of the order of one millisecond. Due to this time limitation the algorithms used to calculate each centroid are fast, but usually achieve low precision. A maximum likelihood algorithm to calculate centroids was developed for ESA Gaia mission, providing a precision very close to the theoretical maximum, the Crámer-Rao lower bound. As this algorithm is computationally complex, it is usually too slow for adaptive optics. A simplified version using look-up tables was developed to study if it could comply with the time requirements. In a previous work, a first version of a FPGA-based system that implements this algorithm has been created. It consists of an embedded system that uses a Microblaze soft processor to control a system with a coprocessor. This coprocessor was created using high level synthesis tools, which proved to be adequate to implement data intensive algorithms. This prototype covered a basic functionality, and had several limitations. The size of the used look-up table was too small, and it only performed one iteration of the centroid algorithm. In this project a more complete version of this prototype is provided, as well as a study of the precision achieved by different look-up table sizes and a study of the convergence of the algorithm. Also the precision of the implemented algorithm is compared with the one achieved by the same algorithm in a software platform. The acceleration of the algorithm has also been measured, and a multicore study has been done