Signal Processing Commons^™

Quality-Driven Cross Layer Design For Multimedia Security Over Resource Constrained Wireless Sensor Networks, Wei Wang

Department of Computer Electronics and Engineering: Dissertations, Theses, and Student Research

The strong need for security guarantee, e.g., integrity and authenticity, as well as privacy and confidentiality in wireless multimedia services has driven the development of an emerging research area in low cost Wireless Multimedia Sensor Networks (WMSNs). Unfortunately, those conventional encryption and authentication techniques cannot be applied directly to WMSNs due to inborn challenges such as extremely limited energy, computing and bandwidth resources. This dissertation provides a quality-driven security design and resource allocation framework for WMSNs. The contribution of this dissertation bridges the inter-disciplinary research gap between high layer multimedia signal processing and low layer computer networking. It formulates the …

Detection And Tracking Of Stealthy Targets Using Particle Filters, Philip M. Losie

Master's Theses

In recent years, the particle filter has gained prominence in the area of target tracking because it is robust to non-linear target motion and non-Gaussian additive noise. Traditional track filters, such as the Kalman filter, have been well studied for linear tracking applications, but perform poorly for non-linear applications. The particle filter has been shown to perform well in non-linear applications. The particle filter method is computationally intensive and advances in processor speed and computational power have allowed this method to be implemented in real-time tracking applications. This thesis explores the use of particle filters to detect and track stealthy …

Violin Note Detector Using Digital Signal Processing, Nathaniel Kyle Mopas

Electrical Engineering

No abstract provided.

Psuedo-Randomly Controlled Analog Synthesizer, Jared Huntington

Electrical Engineering

The goal of this project was to design and build a portable box recreating classic sounds heard in science fiction films. These include sounds ranging from droning hums to bloops and bleeps. Currently no other device is made specifically for generating these sounds. The user controls and manipulates the sounds produced using a combination of switches and knobs to shape the sound generation. The sounds are generated using analog electronics. The project was successful in meeting the desired goal by designing and building a Randomizer, MIDI controller, VCO, LFO, VCA, Ring Modulator, and Fuzz Section. The resulting device is useful …

Sensor Integration For Low-Cost Crash Avoidance, Stephane M. Roussel

Master's Theses

This report is a summary of the development of sensor integration for low-cost crash avoidance for over-land commercial trucks. The goal of the project was to build and test a system composed of low-cost commercially available sensors arranged on a truck trailer to monitor the environment around the truck. The system combines the data from each sensor to increase the reliability of the sensor using a probabilistic data fusion approach. A combination of ultrasonic and magnetoresistive sensors was used in this study. In addition, Radar and digital imaging were investigated as reference signals and possible candidates for additional sensor integration. …

A Robust Method To Detect Concealed Weapons, Anand Gone

Electrical & Computer Engineering Theses & Dissertations

Concealed weapons detection is a large problem that is faced by the Police Department nowadays. There are many disasters caused by poor detection of the weapons. Since public safety is at risk there is a need to design an efficient detector that can detect the weapons hidden under the clothing. This thesis presents a novel method for detecting concealed weapons under clothing using image processing techniques. In this thesis IR imagery is used to capture an image which works on the principle of law of black body radiation. Image thresholding is performed on the captured data using Sauvola's adaptive thresholding …

Signal Classification In Fading Channels Using Cyclic Spectral Analysis, Zhiqiang Wu, Eric C. Like, Vasu D. Chakravarthy, Paul Ratazzi

Student Publications

Cognitive Radio (CR), a hierarchical Dynamic Spectrum Access (DSA) model, has been considered as a strong candidate for future communication systems improving spectrum efficiency utilizing unused spectrum of opportunity. However, to ensure the effectiveness of dynamic spectrum access, accurate signal classification in fading channels at low signal to noise ratio is essential. In this paper, a hierarchical cyclostationary-based classifier is proposed to reliably identify the signal type of a wide range of unknown signals. The proposed system assumes no a priori knowledge of critical signal statistics such as carrier frequency, carrier phase, or symbol rate. The system is designed with …

Anomaly Detection In Hyperspectral Imagery: Comparison Of Methods Using Diurnal And Seasonal Data, Patrick C. Hytla, Russell C. Hardie, Michael T. Eismann, Joseph Meola

Electrical and Computer Engineering Faculty Publications

The use of hyperspectral imaging is a fast growing field with many applications in the civilian, commercial and military sectors. Hyperspectral images are typically composed of many spectral bands in the visible and infrared regions of the electromagnetic spectrum and have the potential to deliver a great deal of information about a remotely sensed scene. One area of interest regarding hyperspectral images is anomaly detection, or the ability to find spectral outliers within a complex background in a scene with no a priori information about the scene or its specific contents. Anomaly detectors typically operate by creating a statistical background …

Networks - I: An Instantiation Of Way Point Routing For Mobile Ad Hoc Networks, Waseem M. Arain, Sayeed Ghani

International Conference on Information and Communication Technologies

Mobile ad hoc networks are increasingly finding their existence in the marketplace heading to a new paradigm of pervasive computing. However there are many areas open to research in the field. Due to node mobility resulting in an ever-changing network topology, conventional routing methods cannot be applied in MANETS. Therefore, this is one of the core areas of research. Researchers are challenged to design protocols that can potentially scale to anything from thousand to tens of thousands of nodes and to reduce the route discovery latency. In this paper a different instantiation of way point routing (WPR) model is proposed, …

Scene-Based Nonuniformity Correction With Reduced Ghosting Using A Gated Lms Algorithm, Russell C. Hardie, Frank Orion Baxley, Brandon J. Brys, Patrick C. Hytla

Electrical and Computer Engineering Faculty Publications

In this paper, we present a scene-based nouniformity correction (NUC) method using a modified adaptive least mean square (LMS) algorithm with a novel gating operation on the updates. The gating is designed to significantly reduce ghosting artifacts produced by many scene-based NUC algorithms by halting updates when temporal variation is lacking. We define the algorithm and present a number of experimental results to demonstrate the efficacy of the proposed method in comparison to several previously published methods including other LMS and constant statistics based methods. The experimental results include simulated imagery and a real infrared image sequence. We show that …

Abstracting Gis Layers From Hyperspectral Imagery, Torsten E. Howard, Michael J. Mendenhall, Gilbert L. Peterson

Faculty Publications

The spectral-spatial relationship of materials in a hyperspectral image cube is exploited to partially automate the creation of Geographic Information System (GIS) layers. The topological neighborhood preservation property of the Self Organizing Map (SOM) is clustered into six (partially overlapping) neighborhoods that are mapped into the image domain to locate in-scene structures of similar material type. GIS layers are abstracted through spatial logical and morphological operations on the six image domain material maps and a novel road finding algorithm connects road segments under significant tree-occlusion resulting in a contiguous road network. It is assumed that specific knowledge of the scene …

Robust Unconstrained Face Detection And Lip Localization Using Gabor Filters, Robert E. Hursig

Master's Theses

Automatic speech recognition (ASR) is a well-researched field of study aimed at augmenting the man-machine interface through interpretation of the spoken word. From in-car voice recognition systems to automated telephone directories, automatic speech recognition technology is becoming increasingly abundant in today’s technological world. Nonetheless, traditional audio-only ASR system performance degrades when employed in noisy environments such as moving vehicles. To improve system performance under these conditions, visual speech information can be incorporated into the ASR system, yielding what is known as audio-video speech recognition (AVASR). A majority of AVASR research focuses on lip parameters extraction within controlled environments, but these …

An Approach Based On Wavelet Decomposition And Neural Network For Ecg Noise Reduction, Suranai Poungponsri

Master's Theses

Electrocardiogram (ECG) signal processing has been the subject of intense research in the past years, due to its strategic place in the detection of several cardiac pathologies. However, ECG signal is frequently corrupted with different types of noises such as 60Hz power line interference, baseline drift, electrode movement and motion artifact, etc. In this thesis, a hybrid two-stage model based on the combination of wavelet decomposition and artificial neural network is proposed for ECG noise reduction based on excellent localization features: wavelet transform and the adaptive learning ability of neural network. Results from the simulations validate the effectiveness of this …

Time-Frequency Analysis Of Intracardiac Electrogram, Erik Brockman

Master's Theses

The Cardiac Rhythm Management Division of St. Jude Medical specializes in the development of implantable cardioverter defibrillators that improve the quality of life for patients diagnosed with a variety of cardiac arrhythmias, especially for patients prone to sudden cardiac death. With the goal to improve detection of cardiac arrhythmias, this study explored the value in time-frequency analysis of intracardiac electrogram in four steps. The first two steps characterized, in the frequency domain, the waveforms that construct the cardiac cycle. The third step developed a new algorithm that putatively provides the least computationally expensive way to identifying cardiac waveforms in the …

Diffusion And Fractional Diffusion Based Image Processing, Jonathan Blackledge

Conference papers

We consider the background to describing strong scattering in terms of diffusive processes based on the diffusion equation. Intermediate strength scattering is then considered in terms of a fractional diffusion equation which is studied using results from fractional calculus. This approach is justified in terms of the generalization of a random walk model with no statistical bias in the phase to a random walk that has a phase bias and is thus, only ‘partially’ or ‘fractionally’ diffusive. A Green’s function solution to the fractional diffusion equation is studied and a result derived that provides a model for an incoherent image …

Inverse Scattering Solutions For Side-Band Signals, Jonathan Blackledge, Timo Hamalainen, Jyrki Joutsensalo

Conference papers

When a signal is recorded that has been physically generated by some scattering process (the interaction of electromagnetic waves with an inhomogeneous dielectric, for example), the `standard model' for the signal (i.e. information content convolved with a characteristic Impulse Response Function) is usually based on a single scattering approximation. An additive noise term is introduced into the model to take into account a range of non-deterministic factors including multiple scattering that, along with electronic noise and other background noise sources, is assumed to be relatively weak. Thus, the standard model is based on a `weak field condition' and the inverse …

Probability Density Functions For Snir In Ds-Cdma, David W. Matolak

Faculty Publications

Analytical expressions for the probability density function of block-wise signal-to-noise-plus-interference ratio for both synchronous and asynchronous direct-sequence spread spectrum code-division multiple access systems are developed, for equal average energy signals on the Gaussian and Rayleigh flat fading channels. Using the standard Gaussian approximation for multi-user interference, accurate density approximations are obtained, which agree very well with computer simulation results.

A Graph-Based Approach To Symbolic Functional Decomposition Of Finite State Machines, Piotr Szotkowski, Mariusz Rawski, Henry Selvaraj

Electrical & Computer Engineering Faculty Research

This paper discusses the symbolic functional decomposition method for implementing finite state machines in field-programmable gate array devices. This method is a viable alternative to the presently widespread two-step approaches to the problem, which consist of separate encoding and mapping stages; the proposed method does not have a separate decomposition step instead, the state's final encoding is introduced gradually on every decomposition iteration. Along with general description of the functional symbolic decomposition method's steps, the paper discusses various algorithms implementing the method and presents an example realisation of the most interesting algorithm. In the end, the paper compares the results …

Synthetic Aperture Radar Imaging Simulated In Matlab, Matthew Schlutz

Master's Theses

This thesis further develops a method from ongoing thesis projects with the goal of generating images using synthetic aperture radar (SAR) simulations coded in MATLAB. The project is supervised by Dr. John Saghri and sponsored by Raytheon Space and Airborne Systems. SAR is a type of imaging radar in which the relative movement of the antenna with respect to the target is utilized. Through the simultaneous processing of the radar reflections over the movement of the antenna via the range Doppler algorithm (RDA), the superior resolution of a theoretical wider antenna, termed synthetic aperture, is obtained. The long term goal …

Time Domain Equalizer Design Using Bit Error Rate Minimization For Uwb Systems, Syed Imtiaz Husain, Jinhong Yuan, Jian Zhang, Richard K. Martin

Faculty Publications

Ultra-wideband (UWB) communication systems occupy huge bandwidths with very low power spectral densities. This feature makes the UWB channels highly rich in resolvable multipaths. To exploit the temporal diversity, the receiver is commonly implemented through a Rake. The aim to capture enough signal energy to maintain an acceptable output signal-to-noise ratio (SNR) dictates a very complicated Rake structure with a large number of fingers. Channel shortening or time domain equalizer (TEQ) can simplify the Rake receiver design by reducing the number of significant taps in the effective channel. In this paper, we first derive the bit error rate (BER) of …

Target Tracking Using Various Filters In Synthetic Aperture Radar Data And Imagery, Jessica L. Kiefer

Master's Theses

This thesis explores the use and accuracy of several discrete-time image filters for the purpose of target tracking in Synthetic Aperture Radar imagery. Both extended targets and point targets are used for tracking, showing the need for different types of filters for each target type.

Monte Carlo analysis is performed on the results of the extended target filter results to determine the absolute mean-squared error between the filter prediction of the target centroid and the actual location of the target centroid. Two different filters were chosen for the extended target: Kalman and H Infinity.

Both the Kalman and H Infinity …

Low Power Fft Processor Design Considerations For Ofdm Communications, David Layne Rushforth

UNLV Theses, Dissertations, Professional Papers, and Capstones

Today's emerging communication technologies require fast processing as well as efficient use of resources. This project specifically addresses the power-efficient design of an FFT processor as it relates to OFDM communications such as cognitive radio. The Fast Fourier Transform (FFT) processor is what enables the efficient modulation in OFDM. As the FFT processor is the most computationally intensive component in OFDM communication, the power efficiency improvement of this component can have great impacts on the overall system. These impacts are significant considering the number of mobile and remote communication devices that rely on limited battery-powered operation. This project explores current …

Human Identification Using Pyroelectric Infrared Sensors, Aron E. Suppes

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of this thesis is to discuss the viability of using pyroelectric infrared (PIR) sensors as a biometric system for human identification.

The human body emits infrared radiation, the distribution of which varies throughout the body, and depends upon the shape and composition of the particular body part. A PIR sensor utilizing a Fresnel lens will respond to this infrared radiation. When a human walks, the motion of the body's individual components form a characteristic gait that is likely to affect a PIR sensor field in a unique way.

A statistical model, such as a Hidden Markov Model, could …

Changes And Challenges In Uncertain Times: When The Only Constant Is Change

ACUTA: Other Publications

The Forums

Since 1997, the annual ACUTA Forum for Strategic Leadership in Information Communications Technology has provided a unique for campus leaders to exchange ideas and discuss issues relevant to the use technology in meeting the goals of higher education. Held in conjunction with ACUTA's Annual Conference and Exhibition, this forum brings together men and women of vision, foresight, and authority to discuss strategic directions for the campus of the future.

Goals

• To provide a venue for the examination of issues and challenges facing the higher education community as we grapple with planning, financing, and implementing technology on our campuses. …

Auditory Coding Based Speech Enhancement, Yao Ren, Michael T. Johnson

Dr. Dolittle Project: A Framework for Classification and Understanding of Animal Vocalizations

This paper demonstrates a speech enhancement system based on an efficient auditory coding approach, coding of time-relative structure using spikes. The spike coding method can more compactly represent the non-stationary characteristics of speech signals than the Fourier transform or wavelet transform. Enhancement is accomplished through the use of MMSE thresholding on the spike code. Experimental results show that compared with the spectral domain logSTSA filter, both the subjective spectrogram evaluation and objective SSNR improvement for the proposed approach is better in suppressing noise in high noise situations, with fewer musical artifacts.P

Optimal Distributed Microphone Phase Estimation, Marek B. Trawicki, Michael T. Johnson

Dr. Dolittle Project: A Framework for Classification and Understanding of Animal Vocalizations

This paper presents a minimum mean-square error spectral phase estimator for speech enhancement in the distributed multiple microphone scenario. The estimator uses Gaussian models for both the speech and noise priors under the assumption of a diffuse incoherent noise field representing ambient noise in a widely dispersed microphone configuration. Experiments demonstrate significant benefits of using the optimal multichannel phase estimator as compared to the noisy phase of a reference channel.

Frequency Diversity For Improving Synthetic Aperture Radar Imaging, Jawad L. Farooq

Theses and Dissertations

In this work, a novel theoretical framework is presented for using recent advances in frequency diversity arrays (FDAs). Unlike a conventional array, the FDA simultaneously transmits a unique frequency from each element in the array. As a result, special time and space properties of the radiation pattern are exploited to improve cross-range resolution. The idealized FDA radiation pattern is compared with and validated against a full-wave electromagnetic solver, and it is shown that the conventional array is a special case of the FDA. A new signal model, based on the FDA, is used to simulate SAR imagery of ideal point …

Application Of Time-Frequency Representation To Non-Stationary Radar Cross Section, John D. Mcshane

Theses and Dissertations

Radar Cross Section (RCS) imaging of a non-wide sense stationary signal poses significant problems in identifying scattering centers in the post processed radar- generated image. A non-wide sense stationary RCS is typically encountered when moving parts on the target impress a phase shift into the backscatter signal that is uncorrelated to the previous return pulse. When the Fourier transform of the phase shifted complex signal is taken, range and cross range information on scattering centers are misplaced. Time Frequency Representations (TFR) must be used to help locate these scattering centers so they can be properly treated to reduce the target’s …

Bit-Error-Rate-Minimizing Channel Shortening Using Post-Feq Diversity Combining And A Genetic Algorithm, Gokhan Altin

Theses and Dissertations

In advanced wireline or wireless communication systems, i.e., DSL, IEEE 802.11a/g, HIPERLAN/2, etc., a cyclic prefix which is proportional to the channel impulse response is needed to append a multicarrier modulation (MCM) frame for operating the MCM accurately. This prefix is used to combat inter symbol interference (ISI). In some cases, the channel impulse response can be longer than the cyclic prefix (CP). One of the most useful techniques to mitigate this problem is reuse of a Channel Shortening Equalizer (CSE) as a linear preprocessor before the MCM receiver in order to shorten the effective channel length. Channel shortening filter …

Two Dimensional Scattering Analysis Of Data-Linked Support Strings For Bistatic Measurement Systems, William Keichel

Theses and Dissertations

Use of data-linked strings to support a bistatic antenna is being considered as a possible improvement to indoor bistatic radar cross section measurement systems. Analysis of candidate data-linked strings is required to understand the potential clutter contribution posed by such a system. The main objective of this research is to determine the scattering properties of four data-linked support string samples. An- other goal is to determine the material properties of the string material through nondestructive means if possible. The final goal is to model the samples as a single wire coated with a dielectric material and determine the validity of …