Signal Processing Commons^™

Design And Control Of A Peristaltic Pump To Simulate Left Atrial Pressure In A Conductive Silicone Model, Jeremy Collins

Mechanical Engineering Undergraduate Honors Theses

According to the CDC, atrial fibrillation is responsible for more than 454,000 hospitalizations and approximately 158,000 deaths per year. A common treatment for atrial fibrillation is catheter ablation, a process in which a long flexible tube is guided through the femoral artery and to the source of arrhythmia in the heart, where it measures the electrical potential at various locations and converts problematic heart tissue to scar tissue via ablation. This paper details the design and control of a low-cost ($400) peristaltic pump system using repetitive control to replicate blood pressure in the left atrium in a conductive silicone model …

Optical Study Of 2-D Detonation Wave Stability, Eulaine T. Grodner

Theses and Dissertations

Fundamental optical detonation study of detonations constricted to a 2-d plane propagation, and detonations propagating around a curve. All images were processed using modern image processing techniques. The optical techniques used were shadowgraph, Schlieren, and chemiluminescence. In the 2-Dstraight channels, it was determined wave stability was a factor of cell size. It was also determined the detonation wave thickness (area between the combustion and shockwave) was a factor of how much heat available for the detonation. For the detonations propagating around a curve, it was determined the three main classifications of wave stability were stable, unstable, and detonation wave restart. …

Light Field Compression And Manipulation Via Residual Convolutional Neural Network, Eisa Hedayati

Dissertations, Master's Theses and Master's Reports

Light field (LF) imaging has gained significant attention due to its recent success in microscopy, 3-dimensional (3D) displaying and rendering, augmented and virtual reality usage. Postprocessing of LF enables us to extract more information from a scene compared to traditional cameras. However, the use of LF is still a research novelty because of the current limitations in capturing high-resolution LF in all of its four dimensions. While researchers are actively improving methods of capturing high-resolution LF's, using simulation, it is possible to explore a high-quality captured LF's properties. The immediate concerns following the LF capture are its storage and processing …

Impacts Of Laboratory Vibrations And Laser Flicker Noise On Digital Holography, Douglas E. Thornton, Mark F. Spencer, Christopher A. Rice, Glen P. Perram

Faculty Publications

In this paper, we experimentally demonstrate the impacts of laboratory vibrations and laser flicker noise on digital holography (DH). Specifically, we measure both the vibration efficiency and the coherence efficiency of our DH system at various focal-plane array integration times and path-length differences between the signal and reference. These efficiencies, in practice, contribute to the overall mixing efficiency, which is a measure for how well the detected signal and reference interfere. The results show that when the integration time is ≤1ms, the laboratory vibrations are negligible with a vibration efficiency of 100%; however, when the integration time equals 100 ms, …

Heel Down And Toe-Off Time Measured With Ultrasonic Doppler System And Force Plate Sensor, Sabin Timsina

Honors Theses

Collie Box is a medical device that measures the gait parameters of the person walk- ing in front of it. This device uses the Ultrasonic Doppler system to extract the heel-contact and toe-off times of a person walking within the range of 2-10 meters. These times are used to determine the leg’s swing phase and double stance times. The ultrasonic transducer of 10mm diameter is driven at 40kHz. At the time of the heel-contact and toe-off, foot velocity is zero while the torso part of the human body is still in motion. The wide directivity of 10mm diameter ultrasonic transducer …

One-Dimensional Multi-Frame Blind Deconvolution Using Astronomical Data For Spatially Separable Objects, Marc R. Brown

Theses and Dissertations

Blind deconvolution is used to complete missions to detect adversary assets in space and to defend the nation's assets. A new algorithm was developed to perform blind deconvolution for objects that are spatially separable using multiple frames of data. This new one-dimensional approach uses the expectation-maximization algorithm to blindly deconvolve spatially separable objects. This object separation reduces the size of the object matrix from an NxN matrix to two singular vectors of length N. With limited knowledge of the object and point spread function the one-dimensional algorithm successfully deconvolved the objects in both simulated and laboratory data.

Measuring Localization Confidence For Quantifying Accuracy And Heterogeneity In Single-Molecule Super-Resolution Microscopy, Hesam Mazidi, Tianben Ding, Arye Nehorai, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

We present a computational method, termed Wasserstein-induced flux (WIF), to robustly quantify the accuracy of individual localizations within a single-molecule localization microscopy (SMLM) dataset without ground- truth knowledge of the sample. WIF relies on the observation that accurate localizations are stable with respect to an arbitrary computational perturbation. Inspired by optimal transport theory, we measure the stability of individual localizations and develop an efficient optimization algorithm to compute WIF. We demonstrate the advantage of WIF in accurately quantifying imaging artifacts in high-density reconstruction of a tubulin network. WIF represents an advance in quantifying systematic errors with unknown and complex distributions, …

Average Speech Directivity, Samuel D. Bellows, Claire M. Pincock, Jennifer K. Whiting, Timothy W. Leishman

Directivity

Speech directivity describes the angular dependence of acoustic radiation from a talker’s mouth and nostrils and diffraction about his or her body and chair (if seated). It is an essential physical aspect of communication affecting sounds and signals in acoustical environments, audio, and telecommunication systems. Because high-resolution, spherically comprehensive measurements of live, phonetically balanced speech have been unavailable in the past, the authors have undertaken research to produce and share such data for simulations of acoustical environments, optimizations of microphone placements, speech studies, and other applications. The measurements included three male and three female talkers who repeated phonetically balanced passages …

Demonstration Of Visible And Near Infrared Raman Spectrometers And Improved Matched Filter Model For Analysis Of Combined Raman Signals, Alexander Matthew Atkinson

Electrical & Computer Engineering Theses & Dissertations

Raman spectroscopy is a powerful analysis technique that has found applications in fields such as analytical chemistry, planetary sciences, and medical diagnostics. Recent studies have shown that analysis of Raman spectral profiles can be greatly assisted by use of computational models with achievements including high accuracy pure sample classification with imbalanced data sets and detection of ideal sample deviations for pharmaceutical quality control. The adoption of automated methods is a necessary step in streamlining the analysis process as Raman hardware becomes more advanced. Due to limits in the architectures of current machine learning based Raman classification models, transfer from pure …

A Harmless Wireless Quantum Alternative To Cell Phones Based On Quantum Noise, Florentin Smarandache, Robert Neil Boyd, Victor Christianto

Branch Mathematics and Statistics Faculty and Staff Publications

In the meantime we know that 4G and 5G technologies cause many harms to human health. Therefore, here we submit a harmless wireless quantum alternative to cell phones. It is our hope that this alternative

Digital Holography Efficiency Experiments For Tactical Applications, Douglas E. Thornton

Theses and Dissertations

Digital holography (DH) uses coherent detection and offers direct access to the complex-optical field to sense and correct image aberrations in low signal-to-noise environments, which is critical for tactical applications. The performance of DH is compared to a similar, well studied deep-turbulence wavefront sensor, the self-referencing interferometer (SRI), with known efficiency losses. Wave optics simulations with deep-turbulence conditions and noise were conducted and the results show that DH outperforms the SRI by 10's of dB due to DH's strong reference. Additionally, efficiency experiments were conducted to investigate DH system losses. The experimental results show that the mixing efficiency (37%) is …

The Challenge For Vision Of Fluctuating Real-World Illumination, David H. Foster

MODVIS Workshop

No abstract provided.

Deep-Turbulence Wavefront Sensing Using Digital Holography In The On-Axis Phase Shifting Recording Geometry With Comparisons To The Self-Referencing Interferometer, Douglas E. Thornton, Mark F. Spencer, Glen P. Perram

Faculty Publications

In this paper, we study the use of digital holography in the on-axis phase-shifting recording geometry for the purposes of deep-turbulence wavefront sensing. In particular, we develop closed-form expressions for the field-estimated Strehl ratio and signal-to-noise ratio for three separate phase-shifting strategies—the four-, three-, and two-step methods. These closed-form expressions compare favorably with our detailed wave-optics simulations, which propagate a point-source beacon through deep-turbulence conditions, model digital holography with noise, and calculate the Monte Carlo averages associated with increasing turbulence strengths and decreasing focal-plane array sampling. Overall, the results show the four-step method is the most efficient phase-shifting strategy and …

Improving Detection Of Dim Targets: Optimization Of A Moment-Based Detection Algorithm, Shannon R. Young

Theses and Dissertations

Wide area motion imagery (WAMI) sensor technology is advancing rapidly. Increases in frame rates and detector array sizes have led to a dramatic increase in the volume of data that can be acquired. Without a corresponding increase in analytical manpower, much of these data remain underutilized. This creates a need for fast, automated, and robust methods for detecting dim, moving signals of interest. Current approaches fall into two categories: detect-before-track (DBT) and track-before-detect (TBD) methods. The DBT methods use thresholding to reduce the quantity of data to be processed, making real time implementation practical but at the cost of the …

High Dynamic Range Optical Devices And Applications., Elijah Robert Jensen

Electronic Theses and Dissertations

Much of what we know about fundamental physical law and the universe derives from observations and measurements using optical methods. The passive use of the electromagnetic spectrum can be the best way of studying physical phenomenon in general with minimal disturbance of the system in the process. While for many applications ambient visible light is sufficient, light outside of the visible range may convey more information. The signals of interest are also often a small fraction of the background, and their changes occur on time scales so quickly that they are visually imperceptible. This thesis reports techniques and technologies developed …

Dark Current Rts-Noise In Silicon Image Sensors, Benjamin William Hendrickson

Dissertations and Theses

Random Telegraph Signal (RTS) noise is a random noise source defined by discrete and metastable changes in the magnitude of a signal. Though observed in a variety of physical processes, RTS is of particular interest to image sensor fabrication where progress in the suppression of other noise sources has elevated its noise contribution to the point of approaching the limiting noise source in scientific applications.

There have been two basic physical sources of RTS noise reported in image sensors. The first involves a charge trap in the oxide layer of the source follower in a CMOS image sensor. The capture …

Plasmonic Grating Geometrics And Wavelength-Dependent Focus Depth In Infrared Detectors, Patrick R. Kennedy

Theses and Dissertations

The objective for this research is to determine a relationship between plasmonic grating geometries and the wavelength-dependent focus depth. This research is focused on enhancing the signal collected by infrared detectors by using a metal grating as a planar lens to focus light in the detecting region of the substrate. This can be used to maintain a thinner absorbing region and possibly to create multi-color imaging in a single pixel. Simulations demonstrate that the plasmonic lens is capable of creating a wavelength dependent focus spot.

Underwater Acoustic Signal Analysis Toolkit, Kirk Bienvenu Jr

LSU New Orleans Theses and Dissertations

This project started early in the summer of 2016 when it became evident there was a need for an effective and efficient signal analysis toolkit for the Littoral Acoustic Demonstration Center Gulf Ecological Monitoring and Modeling (LADC-GEMM) Research Consortium. LADC-GEMM collected underwater acoustic data in the northern Gulf of Mexico during the summer of 2015 using Environmental Acoustic Recording Systems (EARS) buoys. Much of the visualization of data was handled through short scripts and executed through terminal commands, each time requiring the data to be loaded into memory and parameters to be fed through arguments. The vision was to develop …

Synthesis Of Non-Uniformly Correlated Partially Coherent Sources Using A Deformable Mirror, Milo W. Hyde Iv, Santasri Bose-Pillai, Ryan A. Wood

Faculty Publications

The near real-time synthesis of a non-uniformly correlated partially coherent source using a low-actuator-count deformable mirror is demonstrated. The statistical optics theory underpinning the synthesis method is reviewed. The experimental results of a non-uniformly correlated source are presented and compared to theoretical predictions. A discussion on how deformable mirror characteristics such as actuator count and pitch affect source generation is also included.

Real-Time Camera Tracking System Using Optical Flow Feature Points, Daniel D. Doyle, Alan L. Jennings, Jonathan T. Black

AFIT Patents

A new apparatus and method for tracking a moving object with a moving camera provides a real-time, narrow field-of-view, high resolution and on target image by combining commanded motion with an optical flow algorithm for deriving motion and classifying background. Commanded motion means that movement of the pan, tilt and zoom (PTZ) unit is “commanded” by a computer, instead of being observed by the camera, so that the pan, tilt and zoom parameters are known, as opposed to having to be determined, significantly reducing the computational requirements for tracking a moving object. The present invention provides a single camera pan …

Multispectral Identification Array, Zachary D. Eagan

Computer Engineering

The Multispectral Identification Array is a device for taking full image spectroscopy data via the illumination of a subject with sixty-four unique spectra. The array combines images under the illumination spectra to produce an approximate reflectance graph for every pixel in a scene. Acquisition of an entire spectrum allows the array to differentiate objects based on surface material. Spectral graphs produced are highly approximate and should not be used to determine material properties, however the output is sufficiently consistent to allow differentiation and identification of previously sampled subjects. While not sufficiently advanced for use as a replacement to spectroscopy the …

The Fresnel Zone Light Field Spectral Imager, Francis D. Hallada

Theses and Dissertations

This thesis provides a computational model and the first experimental demonstration of a Fresnel zone light field spectral imaging (FZLFSI) system. This type of system couples an axial dispersion binary diffractive optic with light field (plenoptic) camera designs providing a snapshot spectral imaging capability. A computational model of the system was developed based on wave optics methods using Fresnel propagation. It was validated experimentally and provides excellent demonstration of system capabilities. The experimentally demonstrated system was able to synthetically refocus monochromatic images across greater than a 100nm bandwidth. Furthermore, the demonstrated system was modeled to have a full range of …

Nonlinear Dynamics, Bifurcation Maps, Signal Encryption And Decryption Using Acousto-Optic Chaos Under A Variable Aperture Illumination, Monish Ranjan Chatterjee, Suman Chaparala

Electrical and Computer Engineering Faculty Publications

Bragg cell nonlinear dynamics and bifurcation properties under first-order feedback with variable aperture are examined. Chaotic encryption and recovery of low-bandwidth signals, and optimal performance are evaluated for fixed and variable apertures.

Unequal A Priori Probability Multiple Hypothesis Testing In Space Domain Awareness With The Space Surveillance Telescope, Tyler J. Hardy, Stephen C. Cain, Travis F. Blake

Faculty Publications

This paper investigates the ability to improve Space Domain Awareness (SDA) by increasing the number of detectable Resident Space Objects (RSOs) from space surveillance sensors. With matched filter based techniques, the expected impulse response, or Point Spread Function (PSF), is compared against the received data. In the situation where the images are spatially undersampled, the modeled PSF may not match the received data if the RSO does not fall in the center of the pixel. This aliasing can be accounted for with a Multiple Hypothesis Test (MHT). Previously, proposed MHTs have implemented a test with an equal a priori prior …

A Prototype Microwave Cavity Control Circuit For Use In Next Generation Free Electron Laser, Josh Thompson, Peter Neal Barrina, Jiayi Jiang, Joe Frisch, Steve Smith, Daniel Van Winkle

STAR Program Research Presentations

One of the current programs at SLAC National Accelerator Laboratory is the Linac Coherent Light Source, or LCLS. Using the existing hardware of the last third of their linear accelerator (or “linac”), SLAC has created one of the most energetic X-ray free electron lasers (or “FEL”). Since 2009, LCLS has used this FEL to perform a wide range of experiments across all sciences, most notably ultrafast filming at the molecular scale. As requests for beam-time with this laser increases, SLAC is purposing a linac upgrade to better match this demand. This upgrade, named LCLS-II, will replace existing copper radio frequency …

Multiframe Adaptive Wiener Filter Super-Resolution With Jpeg2000-Compressed Images, Barath Narayanan Narayanan, Russell C. Hardie, Eric J. Balster

Electrical and Computer Engineering Faculty Publications

Historically, Joint Photographic Experts Group 2000 (JPEG2000) image compression and multiframe super-resolution (SR) image processing techniques have evolved separately. In this paper, we propose and compare novel processing architectures for applying multiframe SR with JPEG2000 compression. We propose a modified adaptive Wiener filter (AWF) SR method and study its performance as JPEG2000 is incorporated in different ways. In particular, we perform compression prior to SR and compare this to compression after SR. We also compare both independent-frame compression and difference-frame compression approaches. We find that some of the SR artifacts that result from compression can be reduced by decreasing the …

An Experimental Evaluation Of Image Quality For Various Scenarios In A Chromotomographic System With A Spinning Prism, Kyle J. Dufaud

Theses and Dissertations

A lab and eld based hyperspectral chromotomographic imager has been developed at the Air Force Institute of Technology. It is a prototype used to study the requirements for a space-based system. The imager uses a high speed visible band camera behind a direct-vision prism to image both spatial dimensions and the spectral dimension at the same time. Capturing all 3 simultaneously allows for the hyperspectral imaging of transient events. The prism multiplexes the spectral and spatial information, so tomographic reconstruction algorithms must be used to separate hyperspectral channels. Experiments were conducted to compare reconstructed image quality as a function of …

Comparative Analysis Of Reconstructed Image Quality In A Simulated Chromotomographic Imager, Ryan L. Tervo

Theses and Dissertations

A hyperspectral chromotomographic instrument has been developed to determine the spatial and spectral distribution of a target. It does this by recording the dispersed images produced by a rotating direct vision prism with a high speed camera. The recorded images are processed through a tomographic reconstruction algorithm to produce a reconstructed hypercube. A physics-based system model was developed to investigate three areas. The first was how the prism angle selection and range of angles used impacted the reconstructed image quality. The second was an assessment of a new iterative reconstruction algorithm developed to remove artifacts produced in the Back Projection …

Discrimination Between Child And Adult Forms Using Radar Frequency Signature Analysis, Stephanie R. Keith

Theses and Dissertations

In this thesis we develop a method to discriminate between adult and child radar signatures. In particular, we examine radar data measured from behind a wall, which introduces radar signal attenuation and multipath effects. To investigate the child/adult discrimination problem in a through-wall, multipath scenario, a previously developed free-space human scattering model was expanded to incorporate multiple paths, and the effects of transmission through, and reflections from, walls and ground. The ground was modeled as a perfectly reflecting surface, while the walls were modeled as homogeneous concrete slabs. Twenty-five reflection paths were identified, involving the direct paths, as well as …

Development And Characterization Of A Chromotomosynthetic Hyperspectral Imaging System, Randall L. Bostick

Theses and Dissertations

A chromotomosynthetic imaging (CTI) methodology based upon mathematical reconstruction of a set of 2-D spectral projections to collect high-speed (100 Hz) 3-D hyperspectral data cube has been proposed. The CTI system can simultaneously provide usable 3-D spatial and spectral information, provide high-frame rate slitless 1-D spectra, and generate 2-D imagery equivalent to that collected with no prism in the optical system. The wavelength region where prism dispersion is highest (500 nm) is most sensitive to loss of spectral resolution in the presence of systematic error, while wavelengths 600 nm suffer mostly from a shift of the spectral peaks. The quality …