Over the past few decades, significant improvements have been made in our ability to recover arti... more Over the past few decades, significant improvements have been made in our ability to recover articulation from the acoustics of speech. Approaches have evolved from first principle models based on erroneous, simplifying assumptions to plausible, physiologically based data driven methods. One of these methods, called maximum likelihood continuity mapping, is built on the premise that output realizations close together in a high-dimensional observation space had to have been generated by positions close together in a low-dimensional latent space. This model is consistent with our understanding of how speech is produced; low-dimensional articulatory configurations in close proximity to each other help generate the temporally connected acoustics we hear. In this thesis, maximum likelihood continuity mapping is used to discover the intrinsic parameters and, reduce the dimensionality of two speaker-dependent articulation manifolds from the MOCHA-TIMIT data set: the articulatory measuremen...
ABSTRACT We present a novel architecture based upon a Dicke-switched heterodyne radiometer archit... more ABSTRACT We present a novel architecture based upon a Dicke-switched heterodyne radiometer architecture employing two identical input sections consisting of horn and orthomode transducer to detect the difference between the horizontal (H) and vertical (V) polarization states of two separate object patches imaged by the radiometer. We have constructed and described previously a fully polarimetric W-band passive millimeter wave imager constructed to study the phenomenology of anomaly detection using polarimetric image exploitation of the Stokes images. The heterodyne radiometer used a PIN diode switch between the input millimeter wave energy and that of a reference load in order to eliminate the effects of component drifts and to reduce the effects of 1/f noise. The differential approach differs from our previous work by comparing H and V polarization states detected by each of two input horns instead of a reference load to form signals ΔH and ΔV from adjacent paired object patches. This novel imaging approach reduces common mode noise and enhances detection of small changes between the H and V polarization states of two object patches, now given as difference terms of the fully polarimetric radiometer. We present the theory of operation, initial proof of concept experimental results, and extension of the differential radiometer to a system with a binocular fore optics that allow adjustment of the convergence or shear of the object patches as viewed by the differential polarimetric imager.
A prototype active wideband 350 GHz imaging system has been developed to address the urgent need ... more A prototype active wideband 350 GHz imaging system has been developed to address the urgent need for standoff concealed-weapon detection. This system is based on a wideband, heterodyne, frequency-multiplier-based transceiver system coupled to a quasi-optical focusing system and high-speed conical scanner. This system is able to quickly scan personnel for concealed weapons. Additionally, due to the wideband operation, this system
The sub-millimeter (sub-mm) wave frequency band from 300-1000 GHz is currently being developed fo... more The sub-millimeter (sub-mm) wave frequency band from 300-1000 GHz is currently being developed for standoff concealed weapon detection imaging applications. This frequency band is of interest due to the unique combination of high resolution and clothing ...
ABSTRACT As millimeter-wave arrays become available, off-axis imaging performance of the fore opt... more ABSTRACT As millimeter-wave arrays become available, off-axis imaging performance of the fore optics increases in importance due to the relatively large physical extent of the arrays. Typically, simple optical telescope designs are adapted to millimeter-wave imaging but single-mirror spherical or classic conic designs cannot deliver adequate image quality except near the optical axis. Since millimeter-wave designs are quasi-optical, optical ray tracing and commercial design software can be used to optimize designs to improve off-axis imaging as well as minimize cross-polarization. Methods that obey the Dragone-Mizuguchi condition for the design of reflective millimeter-wave telescopes with low cross-polarization also provide additional degrees of freedom that offer larger fields of view than possible with single-reflector designs. Dragone's graphical design method does not lend itself readily to computer-based optical design approaches, but subsequent authors expanded on Dragone's geometric design approach with analytic expressions that describe the location, shape, off-axis height and tilt of the telescope elements that satisfy Dragone's design rules and can be used as a first-order design for subsequent computer-based design and optimization. We investigate two design variants that obey the Dragone-Mizuguchi conditions that exhibit ultra-low cross-polarization and a large diffraction-limited field of view well suited to millimeter-wave imaging arrays.
We present the theory, design, and experimental results obtained from a scanning passive W-band f... more We present the theory, design, and experimental results obtained from a scanning passive W-band fully polarimetric imager. Passive millimeter-wave imaging offers persistent day/nighttime imaging and the ability to penetrate dust, clouds and other obscurants, including clothing and dry soil. The single-pixel scanning imager includes both far-field and near-field fore-optics for investigation of polarization phenomena. Using both fore-optics, a variety of scenes including natural and man-made objects was imaged and these results are presented showing the utility of polarimetric imaging for anomaly detection. Analysis includes conventional Stokes-parameter based approaches as well as multivariate image analysis methods.
Reflectance characteristics of typical Earth surface materials are strongly dependent on the inci... more Reflectance characteristics of typical Earth surface materials are strongly dependent on the incident illumination angle of the sun and viewing geometry of the sensor to the scene. This relationship is summarized in the bidirectional reflectance distribution function (BRDF) of the surface material under investigation. The BRDF, defined to be the ratio of reflected radiance to the incident radiant flux density striking a surface, cannot be measured directly in an operational setting. Laboratory measurements of surface BRDF are possible but tend to be tedious and time consuming. Consequently, the BRDF is often specified with models applied to laboratory spectra obtained under ideal and controlled conditions. In this paper, we evaluate the utility of BRDF modeling in statistical classification/discrimination of Earth surface materials by considering the bidirectional reflectance for multiple viewing angle configurations and the resulting separability between classes.
Journal of the Association for Laboratory Automation, 2009
An automated, flow-through ultrasonic lysis module that is capable of disrupting bacterial spores... more An automated, flow-through ultrasonic lysis module that is capable of disrupting bacterial spores to increase the DNA available for biodetection is described. The system uses a flow-through chamber that allows for direct injection of the sample without the need for a chemical or enzymatic pretreatment step to disrupt the spore coat before lysis. Lysis of Bacillus subtilis spores, a benign simulant of Bacillus anthracis, is achieved by flowing the sample through a tube whose axis is parallel to the faces of two transducers that deliver 10 W cm−2 to the surface of the tube at 1.4-MHz frequency. Increases in amplifiable DNA were assessed by real-time PCR analysis that showed at least a 25-fold increase in amplifiable DNA after ultrasonic treatment with glass beads, compared with controls with no ultrasonic power applied. The ultrasonic system and integrated fluidics are designed as a module that could be incorporated into multistep, automated sample treatment and detection systems for ...
We present experimental results obtained from a scanning passive W-band fully polarimetric imager... more We present experimental results obtained from a scanning passive W-band fully polarimetric imager. Passive millimeter wave imaging offers persistent day/nighttime imaging and the ability to penetrate dust, clouds and other obscurants, as well as thin layers of clothing and even dry soil. The selection of the W-band atmospheric window at 94 GHz offers a compromise as there is sufficient angular
IMTC 2001. Proceedings of the 18th IEEE Instrumentation and Measurement Technology Conference. Rediscovering Measurement in the Age of Informatics (Cat. No.01CH 37188)
The Energy Citations Database (ECD) provides access to historical and current research (1948 to t... more The Energy Citations Database (ECD) provides access to historical and current research (1948 to the present) from the Department of Energy (DOE) and predecessor agencies.
A new approach to the compression of vector quantized (VQ) speech sequences is evaluated. The tec... more A new approach to the compression of vector quantized (VQ) speech sequences is evaluated. The technique uses a method called maximum likelihood continuity mapping to learn a mapping between ariticulation and speech acoustics. Smooth articulator paths are then derived from VQ codes sequences. The paths are subsequently sampled, quantized, and transmitted along with additional information that allows perfect recovery of the VQ code sequences. A decoder takes the transmitted articulator paths and recovers the correct VQ code sequence for resynthesis of the speech waveform. The algorithm has not achieved compression yet, requiring an average of 6.04 bits/frame to transmit a 6 bit VQ code sequence, and 9.96 bits/frame to transmit a 10 bit VQ code sequence. However, modifications to the algorithm are currently under investigation, and we expect to implement improvements to help us compress VQ code sequences. Results of the improved algorithm will be presented at the conference. 1. INTRODU...
Although stochastic models of speech signals (e.g. hidden Markov models, trigrams, etc) have lead... more Although stochastic models of speech signals (e.g. hidden Markov models, trigrams, etc) have lead to impressive improvements in speech recognition accuracy, it has been noted that these models have little relationship to speech production (Lee, 1989), and their recognition performance on some important tasks is far from perfect. However, there have been recent attempts to bridge the gap between speech
Over the past few decades, significant improvements have been made in our ability to recover arti... more Over the past few decades, significant improvements have been made in our ability to recover articulation from the acoustics of speech. Approaches have evolved from first principle models based on erroneous, simplifying assumptions to plausible, physiologically based data driven methods. One of these methods, called maximum likelihood continuity mapping, is built on the premise that output realizations close together in a high-dimensional observation space had to have been generated by positions close together in a low-dimensional latent space. This model is consistent with our understanding of how speech is produced; low-dimensional articulatory configurations in close proximity to each other help generate the temporally connected acoustics we hear. In this thesis, maximum likelihood continuity mapping is used to discover the intrinsic parameters and, reduce the dimensionality of two speaker-dependent articulation manifolds from the MOCHA-TIMIT data set: the articulatory measuremen...
ABSTRACT We present a novel architecture based upon a Dicke-switched heterodyne radiometer archit... more ABSTRACT We present a novel architecture based upon a Dicke-switched heterodyne radiometer architecture employing two identical input sections consisting of horn and orthomode transducer to detect the difference between the horizontal (H) and vertical (V) polarization states of two separate object patches imaged by the radiometer. We have constructed and described previously a fully polarimetric W-band passive millimeter wave imager constructed to study the phenomenology of anomaly detection using polarimetric image exploitation of the Stokes images. The heterodyne radiometer used a PIN diode switch between the input millimeter wave energy and that of a reference load in order to eliminate the effects of component drifts and to reduce the effects of 1/f noise. The differential approach differs from our previous work by comparing H and V polarization states detected by each of two input horns instead of a reference load to form signals ΔH and ΔV from adjacent paired object patches. This novel imaging approach reduces common mode noise and enhances detection of small changes between the H and V polarization states of two object patches, now given as difference terms of the fully polarimetric radiometer. We present the theory of operation, initial proof of concept experimental results, and extension of the differential radiometer to a system with a binocular fore optics that allow adjustment of the convergence or shear of the object patches as viewed by the differential polarimetric imager.
A prototype active wideband 350 GHz imaging system has been developed to address the urgent need ... more A prototype active wideband 350 GHz imaging system has been developed to address the urgent need for standoff concealed-weapon detection. This system is based on a wideband, heterodyne, frequency-multiplier-based transceiver system coupled to a quasi-optical focusing system and high-speed conical scanner. This system is able to quickly scan personnel for concealed weapons. Additionally, due to the wideband operation, this system
The sub-millimeter (sub-mm) wave frequency band from 300-1000 GHz is currently being developed fo... more The sub-millimeter (sub-mm) wave frequency band from 300-1000 GHz is currently being developed for standoff concealed weapon detection imaging applications. This frequency band is of interest due to the unique combination of high resolution and clothing ...
ABSTRACT As millimeter-wave arrays become available, off-axis imaging performance of the fore opt... more ABSTRACT As millimeter-wave arrays become available, off-axis imaging performance of the fore optics increases in importance due to the relatively large physical extent of the arrays. Typically, simple optical telescope designs are adapted to millimeter-wave imaging but single-mirror spherical or classic conic designs cannot deliver adequate image quality except near the optical axis. Since millimeter-wave designs are quasi-optical, optical ray tracing and commercial design software can be used to optimize designs to improve off-axis imaging as well as minimize cross-polarization. Methods that obey the Dragone-Mizuguchi condition for the design of reflective millimeter-wave telescopes with low cross-polarization also provide additional degrees of freedom that offer larger fields of view than possible with single-reflector designs. Dragone's graphical design method does not lend itself readily to computer-based optical design approaches, but subsequent authors expanded on Dragone's geometric design approach with analytic expressions that describe the location, shape, off-axis height and tilt of the telescope elements that satisfy Dragone's design rules and can be used as a first-order design for subsequent computer-based design and optimization. We investigate two design variants that obey the Dragone-Mizuguchi conditions that exhibit ultra-low cross-polarization and a large diffraction-limited field of view well suited to millimeter-wave imaging arrays.
We present the theory, design, and experimental results obtained from a scanning passive W-band f... more We present the theory, design, and experimental results obtained from a scanning passive W-band fully polarimetric imager. Passive millimeter-wave imaging offers persistent day/nighttime imaging and the ability to penetrate dust, clouds and other obscurants, including clothing and dry soil. The single-pixel scanning imager includes both far-field and near-field fore-optics for investigation of polarization phenomena. Using both fore-optics, a variety of scenes including natural and man-made objects was imaged and these results are presented showing the utility of polarimetric imaging for anomaly detection. Analysis includes conventional Stokes-parameter based approaches as well as multivariate image analysis methods.
Reflectance characteristics of typical Earth surface materials are strongly dependent on the inci... more Reflectance characteristics of typical Earth surface materials are strongly dependent on the incident illumination angle of the sun and viewing geometry of the sensor to the scene. This relationship is summarized in the bidirectional reflectance distribution function (BRDF) of the surface material under investigation. The BRDF, defined to be the ratio of reflected radiance to the incident radiant flux density striking a surface, cannot be measured directly in an operational setting. Laboratory measurements of surface BRDF are possible but tend to be tedious and time consuming. Consequently, the BRDF is often specified with models applied to laboratory spectra obtained under ideal and controlled conditions. In this paper, we evaluate the utility of BRDF modeling in statistical classification/discrimination of Earth surface materials by considering the bidirectional reflectance for multiple viewing angle configurations and the resulting separability between classes.
Journal of the Association for Laboratory Automation, 2009
An automated, flow-through ultrasonic lysis module that is capable of disrupting bacterial spores... more An automated, flow-through ultrasonic lysis module that is capable of disrupting bacterial spores to increase the DNA available for biodetection is described. The system uses a flow-through chamber that allows for direct injection of the sample without the need for a chemical or enzymatic pretreatment step to disrupt the spore coat before lysis. Lysis of Bacillus subtilis spores, a benign simulant of Bacillus anthracis, is achieved by flowing the sample through a tube whose axis is parallel to the faces of two transducers that deliver 10 W cm−2 to the surface of the tube at 1.4-MHz frequency. Increases in amplifiable DNA were assessed by real-time PCR analysis that showed at least a 25-fold increase in amplifiable DNA after ultrasonic treatment with glass beads, compared with controls with no ultrasonic power applied. The ultrasonic system and integrated fluidics are designed as a module that could be incorporated into multistep, automated sample treatment and detection systems for ...
We present experimental results obtained from a scanning passive W-band fully polarimetric imager... more We present experimental results obtained from a scanning passive W-band fully polarimetric imager. Passive millimeter wave imaging offers persistent day/nighttime imaging and the ability to penetrate dust, clouds and other obscurants, as well as thin layers of clothing and even dry soil. The selection of the W-band atmospheric window at 94 GHz offers a compromise as there is sufficient angular
IMTC 2001. Proceedings of the 18th IEEE Instrumentation and Measurement Technology Conference. Rediscovering Measurement in the Age of Informatics (Cat. No.01CH 37188)
The Energy Citations Database (ECD) provides access to historical and current research (1948 to t... more The Energy Citations Database (ECD) provides access to historical and current research (1948 to the present) from the Department of Energy (DOE) and predecessor agencies.
A new approach to the compression of vector quantized (VQ) speech sequences is evaluated. The tec... more A new approach to the compression of vector quantized (VQ) speech sequences is evaluated. The technique uses a method called maximum likelihood continuity mapping to learn a mapping between ariticulation and speech acoustics. Smooth articulator paths are then derived from VQ codes sequences. The paths are subsequently sampled, quantized, and transmitted along with additional information that allows perfect recovery of the VQ code sequences. A decoder takes the transmitted articulator paths and recovers the correct VQ code sequence for resynthesis of the speech waveform. The algorithm has not achieved compression yet, requiring an average of 6.04 bits/frame to transmit a 6 bit VQ code sequence, and 9.96 bits/frame to transmit a 10 bit VQ code sequence. However, modifications to the algorithm are currently under investigation, and we expect to implement improvements to help us compress VQ code sequences. Results of the improved algorithm will be presented at the conference. 1. INTRODU...
Although stochastic models of speech signals (e.g. hidden Markov models, trigrams, etc) have lead... more Although stochastic models of speech signals (e.g. hidden Markov models, trigrams, etc) have lead to impressive improvements in speech recognition accuracy, it has been noted that these models have little relationship to speech production (Lee, 1989), and their recognition performance on some important tasks is far from perfect. However, there have been recent attempts to bridge the gap between speech
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