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- Speaker Identification (4)
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Articles 1 - 21 of 21
Full-Text Articles in Signal Processing
Hmm - Impact Of Window Size And Frame Size On Asr Performance, Sanjay A. Patil, Jun Won Suh
Hmm - Impact Of Window Size And Frame Size On Asr Performance, Sanjay A. Patil, Jun Won Suh
Sanjay A. Patil
No abstract provided.
Consistency Results For The Roc Curves Of Fused Classifiers, Kristopher S. Bjerkaas
Consistency Results For The Roc Curves Of Fused Classifiers, Kristopher S. Bjerkaas
Theses and Dissertations
The U.S. Air Force is researching the fusion of multiple classifiers. Given a finite collection of classifiers to be fused, one seeks a new classifier with improved performance. An established performance quantifier is the Receiver Operating Characteristic (ROC) curve, which allows one to view the probability of detection versus the probability of false alarm in one graph. Previous research shows that one does not have to perform tests to determine the ROC curve of this new fused classifier. If the ROC curve for each individual classifier has been determined, then formulas for the ROC curve of the fused classifier exist …
Ultra Wide Band Signal Modeling For Radar Receiver Characterization, Robert J. Backscheider
Ultra Wide Band Signal Modeling For Radar Receiver Characterization, Robert J. Backscheider
Theses and Dissertations
Results for modeling, simulation, and analysis of interference effects that modern wideband signals have on existing narrowband radar system performance are presented. In particular, radar detection performance is characterized using a basic radar receiver model and operational parameters consistent with those of the ARSR-4 air route surveillance radar. Two modern wideband signals (interferers) are addressed in this work, including the GPS military signal (M-Code signal) and a direct sequence ultra wideband (DS-UWB) waveform meeting outdoor emission restrictions imposed by the Federal Communications Commission (FCC). Interference effects are characterized for an unmodulated sinusoidal pulse as well as linear frequency modulated (LFM) …
Non-Cooperative Detection Of Ultra Wideband Signals, Brett D. Gronholz
Non-Cooperative Detection Of Ultra Wideband Signals, Brett D. Gronholz
Theses and Dissertations
Techniques for the non-cooperative (non-matched filter) detection of impulse-like ultra wideband signals using channelized receiver architectures are developed and evaluated. Each technique considered is modeled and simulations conducted to characterize detection performance, the results of which are compared with the detection performance of three receivers: the matched filter receiver, which provides optimum detection performance in AWGN; the radiometer, or energy detector; and the multi-aperture cross correlation receiver. It is shown that a channelized receiver (with no downconversion) can provide approximately 2.5 dB improvement over the radiometer when performing detection using the temporal-temporal matrix (TTM). The TTM processing technique provides the …
Speaker Identification Using Usable Speech Concept, Ananth N. Iyer, Brett Y. Smolenski, Robert E. Yantorno, Jashmin K. Shah, Edward J. Cupples, Stanley J. Wenndt
Speaker Identification Using Usable Speech Concept, Ananth N. Iyer, Brett Y. Smolenski, Robert E. Yantorno, Jashmin K. Shah, Edward J. Cupples, Stanley J. Wenndt
Ananth N Iyer
Most signal processing involves processing a signal without concern for the quality or information content of that signal. In speech processing, speech is processed on a frame-by-frame basis, usually only with concern that the frame is either speech or silence. However, knowing how reliable the information is in a frame of speech can be very important and useful. This is where usable speech detection and extraction can play a very important role. The usable speech frames can be defined as frames of speech that contain higher information content compared to unusable frames with reference to a particular application. We have …
Robust Speaker Verification With Principal Pitch Components, Robert M. Nickel, Sachin P. Oswal, Ananth N. Iyer
Robust Speaker Verification With Principal Pitch Components, Robert M. Nickel, Sachin P. Oswal, Ananth N. Iyer
Ananth N Iyer
We are presenting a new method that improves the accuracy of text dependent speaker identification systems. The new method exploits a set of novel speech features that is derived from a principal component analysis (PC) of voiced speech segments. The new PC features are only weakly correlated with the corresponding cepstral features. A distance measure that combines both, cepstral and PC pitch features provides a discriminative power that cannot be achieved with cepstral features alone. It is well known that the discriminative power of cepstral features declines if the dimensionality of the feature space is increased beyond its optimal value. …
Sequential K-Nn Pattern Recognition For Usable Speech Classification, Jashmin K. Shah, Brett Y. Smolenski, Robert E. Yantorno, Ananth N. Iyer
Sequential K-Nn Pattern Recognition For Usable Speech Classification, Jashmin K. Shah, Brett Y. Smolenski, Robert E. Yantorno, Ananth N. Iyer
Ananth N Iyer
The accuracy of speech processing techniques degrades when operating in a co-channel environment. Co-channel speech occurs when more than one person is talking at the same time. The idea of usable speech segmentation is to identify and extract those portions of co-channel speech that are minimally degraded but still useful for speech processing application such as speaker identification. Usable speech measures are features that are extracted from the co-channel signal to distinguish between usable and unusable speech. In this paper, a new usable speech extraction technique is presented. The new method extracts features recursively and variable length segmentation is performed …
A Fast And Simple Algorithm For Computing M Shortest Paths In Stage Graph, M. Sherwood, Laxmi P. Gewali, Henry Selvaraj, Venkatesan Muthukumar
A Fast And Simple Algorithm For Computing M Shortest Paths In Stage Graph, M. Sherwood, Laxmi P. Gewali, Henry Selvaraj, Venkatesan Muthukumar
Electrical & Computer Engineering Faculty Research
We consider the problem of computing m shortest paths between a source node s and a target node t in a stage graph. Polynomial time algorithms known to solve this problem use complicated data structures. This paper proposes a very simple algorithm for computing all m shortest paths in a stage graph efficiently. The proposed algorithm does not use any complicated data structure and can be implemented in a straightforward way by using only array data structure. This problem appears as a sub-problem for planning risk reduced multiple k-legged trajectories for aerial vehicles.
Scatterer Size Estimation In Pulse-Echo Ultrasound Using Focused Sources: Calibration Measurements And Phantom Experiments, Timothy A. Bigelow, William D. O'Brien
Scatterer Size Estimation In Pulse-Echo Ultrasound Using Focused Sources: Calibration Measurements And Phantom Experiments, Timothy A. Bigelow, William D. O'Brien
Timothy A. Bigelow
In a companion paper [T. A. Bigelow and W. D. O'Brien Jr., J. Acoust. Soc. Am. 116, 578 (2004)], theory, supported by simulations, showed that accurate scatterer size estimates could be obtained using highly focused sources provided that the derived generalized attenuation-compensation function was used and the velocity potential field near the focus could be approximated as a three-dimensional Gaussian. Herein, the theory is further evaluated via experimental studies. A calibration technique is developed to find the necessary equivalent Gaussian dimensions for a focused source using reflections obtained from a rigid plane scanned through the focus. Then, the theoretical analysis …
Scatterer Size Estimation In Pulse-Echo Ultrasound Using Focused Sources: Theoretical Approximations And Simulation Analysis, Timothy A. Bigelow, William D. O'Brien
Scatterer Size Estimation In Pulse-Echo Ultrasound Using Focused Sources: Theoretical Approximations And Simulation Analysis, Timothy A. Bigelow, William D. O'Brien
Timothy A. Bigelow
The speckle in ultrasound images has long been thought to contain information related to the tissue microstructure. Many different investigators have analyzed the frequency characteristics of the backscattered signals to estimate the scatterer acoustic concentration and size. Previous work has been mostly restricted to unfocused or weakly focused ultrasound sources, thus limiting its implementation with diagnostically relevant fields. Herein, we derive equations capable of estimating the size of a-scatterer for any reasonably focused source provided that the velocity potential field in the focal region can be approximated as a three-dimensional Gaussian beam, scatterers are a sufficient distance from the source, …
Utilizing Near-Field Measurements To Characterize Far-Field Radar Signatures, John R. Watkins
Utilizing Near-Field Measurements To Characterize Far-Field Radar Signatures, John R. Watkins
Theses and Dissertations
The increased need for stealth aircraft requires an on-site Far-Field (FF) Radar Cross-Section (RCS) measurement process. Conducting these measurements in on-site Near-Field (NF) monostatic facilities results in significant savings for manufacturers and acquisition programs. However, NF measurements are not directly extended to a FF RCS. Therefore, a large target Near-Field to Far-Field Transformation (NFFFT) is needed for RCS measurements. One approach requires an Inverse Synthetic Aperture Radar (ISAR) process to create accurate scattering maps. The focus of this work is the development of accurate NF scattering maps generated by a monostatic ISAR process. As a first look, the process is …
Usable Speech Detection Using A Context Dependent Gaussian Mixture Model Classifier, Robert E. Yantorno, Brett Y. Smolenski, Ananth N. Iyer, Jashmin K. Shah
Usable Speech Detection Using A Context Dependent Gaussian Mixture Model Classifier, Robert E. Yantorno, Brett Y. Smolenski, Ananth N. Iyer, Jashmin K. Shah
Ananth N Iyer
Speech that is corrupted by nonstationary interference, but contains segments that are still usable for applications such as speaker identification or speech recognition, is referred to as "usable" speech. A common example of nonstationary interference occurs when there is more than one person talking at the same time, which is known as co-channel speech. In general the above speech processing applications do not work in co-channel environments; however, they can work on the extracted usable segments. Unfortunately, currently available usable speech measures only detect about 75% of the total available usable speech. The first reason for this high error stems …
A Tutorial On Text-Independent Speaker Verification, Frédéric Bimbot, Jean-François Bonastre, Corinne Fredouille, Guillaume Gravier, Ivan Magrin-Chagnolleau, Sylvain Meignier, Teva Merlin, Javier Ortega-García, Dijana Petrovska-Delacrétaz, Douglas A. Reynolds
A Tutorial On Text-Independent Speaker Verification, Frédéric Bimbot, Jean-François Bonastre, Corinne Fredouille, Guillaume Gravier, Ivan Magrin-Chagnolleau, Sylvain Meignier, Teva Merlin, Javier Ortega-García, Dijana Petrovska-Delacrétaz, Douglas A. Reynolds
Presidential Fellows Articles and Research
This paper presents an overview of a state-of-the-art text-independent speaker verification system. First, an introduction proposes a modular scheme of the training and test phases of a speaker verification system. Then, the most commonly speech parameterization used in speaker verification, namely, cepstral analysis, is detailed. Gaussian mixture modeling, which is the speaker modeling technique used in most systems, is then explained. A few speaker modeling alternatives, namely, neural networks and support vector machines, are mentioned. Normalization of scores is then explained, as this is a very important step to deal with real-world data. The evaluation of a speaker verification system …
A Linear Subspace Approach To Burst Communication Signal Processing, Daniel E. Gisselquist
A Linear Subspace Approach To Burst Communication Signal Processing, Daniel E. Gisselquist
Theses and Dissertations
This dissertation focuses on the topic of burst signal communications in a high interference environment. It derives new signal processing algorithms from a mathematical linear subspace approach instead of the common stationary or cyclostationary approach. The research developed new algorithms that have well-known optimality criteria associated with them. The investigation demonstrated a unique class of multisensor filters having a lower mean square error than all other known filters, a maximum likelihood time difference of arrival estimator that outperformed previously optimal estimators, and a signal presence detector having a selectivity unparalleled in burst interference environments. It was further shown that these …
Ultra-Wideband (Uwb) Communications: New Paradigms And Opportunities, Robert H. Morelos-Zaragoza
Ultra-Wideband (Uwb) Communications: New Paradigms And Opportunities, Robert H. Morelos-Zaragoza
Robert Henry Morelos-Zaragoza
In this talk, the unique characteristics of ultra wideband (UWB) communications systems are introduced. Receiver design considerations are presented. Focus is on the relation between the symbol duration and the delay spread of the channel. This determines whether the receiver should use a Rake receiver (Spread-spectrum system) or an equalizer (multiple carrier or OFDM system).
Image Super-Resolution Using Adaptive 2-D Gaussian Basis Function Interpolation, Terence D. Hunt
Image Super-Resolution Using Adaptive 2-D Gaussian Basis Function Interpolation, Terence D. Hunt
Theses and Dissertations
Digital image interpolation using Gaussian radial basis functions has been implemented by several investigators, and promising results have been obtained; however, determining the basis function variance has been problematic. Here, adaptive Gaussian basis functions fit the mean vector and covariance matrix of a non-radial Gaussian function to each pixel and its neighbors, which enables edges and other image characteristics to be more effectively represented. The interpolation is constrained to reproduce the original image mean gray level, and the mean basis function variance is determined using the expected image smoothness for the increased resolution. Test outputs from the resulting Adaptive Gaussian …
Enhancing The Instantaneous Dynamic Range Of Electronic Warfare Receivers Using Statistical Signal Processing, Bryan E. Smith
Enhancing The Instantaneous Dynamic Range Of Electronic Warfare Receivers Using Statistical Signal Processing, Bryan E. Smith
Theses and Dissertations
Accurately processing multiple, time-coincident signals presents a challenge to Electronic Warfare (EW) receivers, especially if the signals are close in frequency and/or mismatched in amplitude. The metric that quantifies an EW receiver's ability to measure time-coincident signals is the Instantaneous Dynamic Range (IDR), defined for a given frequency estimation accuracy, a given frequency separation and a given SNR as the maximum signal amplitude ratio that can be accommodated. Using a two sinusoid time-series model, this thesis analyzes IDR for ideal intercept and parametric digital EW receivers. In general, the number of signals contained in the EW receiver measurement interval is …
Geolocation Of An Audio Source In A Multipath Environment Using Time-Of-Arrival, Jeffrey A. Boggs
Geolocation Of An Audio Source In A Multipath Environment Using Time-Of-Arrival, Jeffrey A. Boggs
Theses and Dissertations
The Air Force and the Department of Defense (DoD) are continually searching for ways to protect U.S. forces, both stateside and abroad. One continuing threat, especially in the current world environment, is gunfire from an unseen sniper. Designated areas, such as a forward deployed base or motorcade route, need to be continuously monitored for sniper fire. Once detected, these gunmen need to be located in real time. One possible method for accomplishing this task is to geolocate the audio signals generated using time-of-arrival (TOA) algorithms. These algorithms rely on direct-path measurements for accuracy. Multipath environments therefore pose a problem when …
Forward Looking Radar: Interference Modelling, Characterization, And Suppression, James T. Caldwell
Forward Looking Radar: Interference Modelling, Characterization, And Suppression, James T. Caldwell
Theses and Dissertations
This research characterizes forward looking radar performance while noting differences with traditionally examined sidelooking radar. The target detection problem for forward looking radar is extremely difficult due to the severe, heterogeneous and range dependent ground clutter. Consequently, forward looking radar detection represents an important but overlooked topic because of the increased difficulty compared to sidelooking radar. This void must be filled since most fighter aircraft use forward looking radar, making this topic intensely interesting to the Air Force. After characterizing forward looking radar performance, basic radar concepts along with advanced adaptive interference suppression techniques improve the output Signal-to-Interference-plus-Noise Ratio (SINR) …
Characterization Of The Target-Mount Interaction In Radar Cross Section Measurement Calibrations, Donald W. Powers
Characterization Of The Target-Mount Interaction In Radar Cross Section Measurement Calibrations, Donald W. Powers
Theses and Dissertations
Radar Cross Section (RCS) measurements are quintessential in understanding target scattering phenomenon. The reduced RCS of modern weapons systems stresses the capability of current RCS measurement ranges. A limiting factor that has recently become more significant is the electromagnetic coupling between a test target and the mounting hardware used to support it and control its orientation during the RCS measurement. Equally important is the electromagnetic coupling between the RCS calibration artifact and its mount, which provides an opportunity to explore the coupling phenomena without delving into operationally sensitive areas. The primary research goal was to characterize the interaction between a …
A Fast And Simple Algorithm For Computing M-Shortest Paths In State Graph, M. Sherwood, Laxmi P. Gewali, Henry Selvaraj, Venkatesan Muthukumar
A Fast And Simple Algorithm For Computing M-Shortest Paths In State Graph, M. Sherwood, Laxmi P. Gewali, Henry Selvaraj, Venkatesan Muthukumar
Electrical & Computer Engineering Faculty Research
We consider the problem of computing m shortest paths between a source node s and a target node t in a stage graph. Polynomial time algorithms known to solve this problem use complicated data structures. This paper proposes a very simple algorithm for computing all m shortest paths in a stage graph efficiently. The proposed algorithm does not use any complicated data structure and can be implemented in a straightforward way by using only array data structure. This problem appears as a sub-problem for planning risk reduced multiple k-legged trajectories for aerial vehicles.