published_or_final_version / abstract / Electrical and Electronic Engineering / Master / Master of Philosophy

In recent years, a growing number of diagnostic examinations in a hospital are being generated by digitally formatted imaging modalities. The evolution of these systems has led to the development of a totally digitized imaging system, which is called Picture Archiving and Communication System (PACS). A high speed computer network plays a very important role in the design of a Picture Archiving and Communication System. The computer network must not only offer a high data rate, but also it must be structured to satisfy the PACS requirements efficiently. In this dissertation, a computer network, called PACnet, is proposed for PACS. The PACnet is designed to carry image, voice, image pointing overlay, and intermittent data over a 200 Mbps dual fiber optic ring network. The PACnet provides a data packet channel and image and voice channels based on Time Division Multiple Access (TDMA) technique. The intermittent data is transmitted over a data packet channel using a modified token passing scheme. The voice and image pointing overlay are transferred between two stations in real-time to support the consultive nature of a radiology department using circuit switching techniques. Typical 50 mega-bit images are transmitted over the image channel in less than a second using circuit switching techniques. A technique, called adaptive variable frame size, is developed for PACnet to achieve high network utilization and short response time. This technique allows the data packet traffic to use any residual voice or image traffic momentarily available due to variation in voice traffic or absence of images. To achieve optimal design parameters for network and interfaces, the PACnet is also simulated under different conditions.

The main thrust of this dissertation is the application of statistics and information theory to design, analysis and estimation pertaining to image-forming systems. This study explores the application of Shannon's information in pupil design, the characterization of noise, and study of its behavior in a specific electro-optical system, and estimation of the degraded spread function in atmospherical imagery using the maximum entropy method. Our study shows that a pupil designed to maximize Shannon's information throughput is an apodizer, resulting in resolution and contrast enhancement when compared to the diffraction-limited case. The Strehl ratio is about 0.55. Investigation of statistical and spectral properties as a function of gray level in an electro-optical tracking system indicates that the noise is "white," having a wide band and a close-to-Gaussian distribution. Estimating the spread function via maximum entropy technique has revealed some remarkable results. Using an edge as the object, simulation studies predict a superior estimate in the mean squared error sense to those of the least squares in the presence of three types of noise (signal-dependent Gaussian and Poisson, and signal-independent Gaussian noise). Information theory, linear systems theory, sampling theory and more particularly, statistics and the Fast Fourier Transform are used to derive our results.

Wavefront controller optimization is important in achieving the best possible image quality for adaptive optics systems on the current generation of large and very large aperture telescopes. This will become even more critical when we consider the demands of the next generation of extremely large telescopes currently under development. These telescopes will be capable of providing resolution which is significantly greater than the current generation of optical/IR telescopes. However, reaching the full resolving potential of these instruments will require a careful analysis of all disturbance sources, then optimizing the wavefront controller to provide the best possible image quality given the desired science goals and system constraints. Along with atmospheric turbulence and sensor noise, structural vibration will play an important part in determining the overall image quality obtained. The next generation of very large aperture telescopes currently being developed will require assessing the effects of structural vibration on closed loop AO system performance as an integral part of the overall system design. Telescope structural vibrations can seriously degrade image quality, resulting in actual spot full width half maximum (FWHM) and angular resolution much worse than the theoretical limit. Strehl ratio can also be significantly degraded by structural vibration as energy is dispersed over a much larger area of the detector. In addition to increasing telescope diameter to obtain higher resolution, there has also been significant interest in adaptive optics systems which observe at shorter wavelength from the near infrared to visible (VNIR) wavelengths, at or near 0.7 microns. This will require significant reduction in the overall wavefront residuals as compared with current systems, and will therefore make assessment and optimization of the wavefront controller even more critical for obtaining good AO system performance in the VNIR regime.

Thermography is a useful tool for analyzing spinal nerve root irritation, but interpretation of digital infrared images is often qualitative and subjective. A new quantitative, computer-aided method for analyzing thermograms, utilizing the human dermatome map, is presented. Image processing and pattern recognition principles needed to accomplish this goal are discussed. Algorithms for segmentation, boundary detection and interpretation of thermograms are presented. An interactive, user-friendly program to perform this analysis has been developed. Due to the relatively large number of images in an exam, speed and simplicity were emphasized in algorithm development. The results obtained correlate well with clinical data and show promise for aiding the diagnosis of spinal nerve root irritation.

This paper describes the design and simulation of a network interface unit (NIU) for a picture archiving and communication system (PACS) network called PACnet. PACnet is a dual fiber optic ring network under development at the Computer Engineering Research Laboratory of the University of Arizona. This network integrates voice, data, and image communications in a hospital environment and supports a throughput rate between 200-500 megabits per second. At each node in the network, an NIU implements the Data Link Layer and Physical Layer protocols of PACnet. The initial network interface unit design for PACnet was a functional description of NIU protocols and major components. In order to construct a demonstration prototype of PACnet,the NIU description must be refined and an architecture must be specified. The NIU design is specified and simulated using the hardware description language VHDL. Simulation results provide information on NIU timing characteristics and logic families required to implement the NIU.

The transit method is considered to be one of the most promising for discovering extrasolar planets. However, the method requires photometric precision of better than ∼ 1%. If we are able to achieve this kind of accuracy, then we are set to discover extrasolar planets. The uniqueness of my experiment will lead to the discovery of transiting planets around the brightest and most important stars quicker than the competitors in the field. The importance of the transit method stems from being able to supply many more planetary parameters than other methods, which plays a crucial role in testing planet formation theories. This thesis is divided into eight chapters. The first chapter provides a general background about transits and their theory. We discuss other methods of extrasolar planet detection, recent developments, future space missions, and what we have learned so far about properties of hot Jupiters. The second chapter details the theory of signals and noise on CCDs followed by the design of the PASS0 experiment. The third chapter reports on the difference imaging data pipeline that we developed and applied to a set of PASS0 data to search for transiting planets. The fourth chapter shows how we apply the PASS0 pipeline to SuperWASP data and improve on the accuracy obtained with their aperture photometry pipeline. The fifth chapter reports on the search for variable stars from the PASS0 and SuperWASP data sets that we consider in this thesis. In the sixth chapter we perform a transit search on the PASS0 and SuperWASP data sets and report the results. In the seventh chapter we use the PASS0 pipeline to process a full season of observing data from 2007 for two recent planet discoveries, WASP-7b and WASP-8b, that have not yet been announced. We analyse their lightcurves and predict their radii. Finally we conclude in the eighth chapter.

A 915 MHz wireless IR image transfer system, comprised of an IR-160 Thermal Camera and MDS iNet 900 transceivers, was assessed for image transfer capabilities in different environments. Image transfer through natural and artificial obstructions, the capability of transferring images under urban environments, and an exploration of interference issues associated with RF communication links were investigated in detail. Concrete, wood, various construction materials, and building walls were examined to assess indoor propagation capabilities. Data transmission through random trees, buildings, foliage under various atmospheric conditions is also evaluated for outdoor system capabilities. A maximum free space range for acceptable IR image transferring is determined as 23 miles for line of sight (LOS). Non line of sight (NLOS) urban environment measurements revealed that urban path loss (15-60 dBm) is highly dependent on antenna orientation and obstruction geometry rather than the T-R separation distance.

Though several clinical monitoring ways exist and have been applied to detect cardiac atril fibrillation (A-Fib) and other arrhythmia, these medical interventions and the ensuing clinical treatments are after the fact and costly. Current portable healthcare monitoring systems come in the form of Ambulatory Event Monitors. They are small, battery-operated electrocardiograph devices used to record the heart's rhythm and activity. However, they are not energy-aware ; they are not personalized ; they require long battery life, and ultimately fall short on delivering real-time continuous detection of arrhythmia and specifically progressive development of cardiac A-Fib. The focus of this dissertation is the design of a class of adaptive and efficient energy-aware real-time detection models for monitoring, early real-time detection and reporting of progressive development of cardiac A-Fib.... The design promises to have a greater positive public health impact from predicting A-Fib and providing a viable approach to meeting the energy needs of current and future real-time monitoring, detecting and reporting required in wearable computing healthcare applications that are constrained by scarce energy resources. / by Redjem Bouhenguel. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

With augmenting security concerns and decreasing costs of surveillance and computing equipment, research on automated systems for object detection has been increasing, but the majority of the studies focus their attention on sequences where high resolution objects are present. The main objective of this work is the detection and extraction of information of low resolution objects (e.g. objects that are so far away from the camera that they occupy only tens of pixels) in order to provide a base for higher level information operations such as classification and behavioral analysis. The system proposed is composed of four stages (preprocessing, background modeling, information extraction, and post processing) and uses context based region of importance selection, histogram equalization, background subtraction and morphological filtering techniques. The result is a system capable of detecting and tracking low resolution objects in a controlled background scene which can be a base for systems with higher complexity. / by Diego F. Pava. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.