2016 41st International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 2016
Single Pixel Camera Imaging Setup Wave Propagation Model of the SPC Simulation Results References... more Single Pixel Camera Imaging Setup Wave Propagation Model of the SPC Simulation Results References and Acknowledgements Spatially resolved terahertz measurements usually require either mechanical scanning, large and expensive detector arrays, or a combination thereof. So called Single Pixel Cameras (SPCs), consisting mainly of a Spatial Light Modulator (SLM) and a single pixel detector, provide an alternative approach, which has already been demonstrated [1, 2]. For a successful image acquisition, the setup, and especially the behaviour of the SLM, needs to be physically well-understood. A wave propagation model was developed that takes into account the nature of coherent radiation emitted by the THz source. It is capable of predicting signal values at the single pixel detector for a given wavelength, spatial filter configuration, flat object and detector position. The developed model is presented here and verified using a 0.345 THz SPC setup.
Conference of the International Speech Communication Association, 2001
Page 1. Eurospeech 2001 - Scandinavia Using Boosting and POS Word Graph Tagging to Improve Speech... more Page 1. Eurospeech 2001 - Scandinavia Using Boosting and POS Word Graph Tagging to Improve Speech Recognition Christer Samuelsson 1 and James L. Hieronymus 2 ... Morgan Kaufmann. [Manning & Carpenter 1997] Christopher Manning and Bob Carpenter. 1997. ...
Coarticulation alters the vowel formant characteristics in continuous speech. Studies of isolated... more Coarticulation alters the vowel formant characteristics in continuous speech. Studies of isolated monosyllables in the literature suggest that some phonemes cause more severe distortions than others. The largest changes are caused by lrl, Ill, lwl. Unstressed vowels are most affected. Previous studies by Holmes [6] and by us [14] indicate that these effects are even larger for continuous speech. Vowel recognition algorithms which do not take context into account in continuous speech normally achieve correct recognition of approximately 75 % for the three top choices from the recognizer, with the first choice approximately 60 %.. By developing methods which explicitly model the phonetic context, higher levels of performance can to be achieved. An ongoing study is being made of all 16 of the American English vowels using subsets of the DARPA acoustic-phonetic data base. Formants are obtained and normalized for each talkers formant range based on one sentence. The resulting formant tra...
International Conference on Acoustics, Speech, and Signal Processing
An ongoing study is reported of all sixteen of the American English vowels using subsets of the D... more An ongoing study is reported of all sixteen of the American English vowels using subsets of the DARPA acoustic-phonetic database. Formants are obtained and normalized for each talker's formant range based on one sentence. The resulting formant tracks are smoothed using splines and sampled at nine equally spaced points in time within vowel-centered triphone regions. Triphones with semivowels in them are clustered separately. These formant values are k-means clustered using subsets of the sampled formant values. The additional supervised training is done using other parameters, including duration. The resulting clusters are used as a classifier on the basis of the modified Euclidean distance from the cluster centers. This results in approximately 80% first choice vowel recognition of the outer edges of the vowel quadrilateral. Stressed vowels were found to have spectra which statistically were no more stable than unstressed vowels.<<ETX>>
New missions of space exploration will require unprecedented levels of autonomy to successfully a... more New missions of space exploration will require unprecedented levels of autonomy to successfully accomplish their objectives. Both inherent complexity and communication distances will preclude levels of human involvement common to current and previous space flight missions. With exponentially increasing capabilities of computer hardware and software, including networks and communication systems, a new balance of work is being developed between humans
2015 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2015
This paper investigates a weighted finite state transducer (WFST) based syllable decoding and tra... more This paper investigates a weighted finite state transducer (WFST) based syllable decoding and transduction method for keyword search (KWS), and compares it with sub-word search and phone confusion methods in detail. Acoustic context dependent phone models are trained from word forced alignments and then used for syllable decoding and lattice generation. Out-of-vocabulary (OOV) keyword pronunciations are produced using a grapheme-to-syllable (G2S) system and then used to construct a lexical transducer. The lexical transducer is then composed with a keyword-boosted language model (LM) to transduce the syllable lattices to word lattices for final KWS. Word Error Rates (WER) and KWS results are reported for 5 different languages. It is shown that the syllable transduction method gives comparable KWS results to the syllable search and phone confusion methods. Combination of these three methods further improves OOV KWS performance.
The Journal of the Acoustical Society of America, 2008
Research was conducted to examine interactions between acoustic signals and mechanical factors re... more Research was conducted to examine interactions between acoustic signals and mechanical factors relevant to the design of improved auditory displays and noise mitigation for future NASA Spacesuits. Data were collected at NASA Johnson Space Center for the current Mark III advanced prototype surface suit during walking, walking with arm motion, and while seated. Measurements were made using multiple microphones (both head mounted and helmet mounted) and a tri-axial accelerometer to evaluate the effects of suit-borne vibration on overall background noise. Footfall impacts were found to create temporary depolarization of condenser microphone signals, and microphone positioning had a strong effect on signal-noise ratio, partially due to the effect of the helmet enclosure. The results indicate noise mitigation and signal conditioning strategies for improving lunar suit audio voice communications under extra-vehicular (EVA) conditions. Funded by a directed research program of NASA's Spa...
The Journal of the Acoustical Society of America, 1986
The goal is to develop a speaker-independent, semivowel detector-classifier for use with continuo... more The goal is to develop a speaker-independent, semivowel detector-classifier for use with continuous speech. Preliminary analysis of semivowels within continuous speech indicates large within-(and between) speaker variability in the respective semivowel formant frequencies, amplitudes, and durations of steady states and transitions. Deviations from textbook descriptions based on isolated words are significant. Coarticulation effects are also large. Nevertheless, through the use of energy, energy ratios, zero crossings, and signal envelopes, a logical analytical scheme was developed that classifies segments of continuous speech as: semivowel, high-front vowel, vowel, nasal, fricative, stop, or plosive. The specific characteristics of this scheme will be discussed and the computer-generated displays that were used will be presented. Results of using this scheme on a large corpus of phonetically labeled speech will be presented. [Work supported, in part, by DARPA.]
The Journal of the Acoustical Society of America, 1984
Early results on synthetic-vowel formant amplitude discrimination by Flanagan [J. Acoust. Soc. Am... more Early results on synthetic-vowel formant amplitude discrimination by Flanagan [J. Acoust. Soc. Am. 27, 1223–1225 (1955); J. Speech Hear. Disord. 22, 205–212 (1957)] indicated that ΔI for overall vowel level was about ± 1.5 dB, but that ΔI for F2 was about ± 4 dB. The latter result was for F2 ≃ − 12dB re: F1 for the “comparison” vowel. Subjects made a same-different judgment which may have affected the interpretation of these results. Here we report ΔI for several “comparison” vowels which differ in amplitude relations among F1, F2, and F3. In addition, we report on perception of extreme shifts in formant amplitude, Implications for computer recognition of speech will be discussed.
The Journal of the Acoustical Society of America, 1994
A language identification (LID) system that uses phonemotactic models in addition to phoneme mode... more A language identification (LID) system that uses phonemotactic models in addition to phoneme models to identify languages is described. The proposed LID system is trained and tested using the OGI multilanguage telephone speech database. The continuous density second-order ergodic variable duration hidden Markov phonemic models are trained for each language using a high accuracy phoneme recognition system developed at Bell Laboratories. The phonemotactic models for each language are trained using a text corpora of about ten million words and grapheme to phoneme converters. The language Li of an incoming speech signal x is hypothesized as the one that produced the highest likelihood f(x‖λi)f(λi‖Li) for all the phonemic models λi of a given set with the phonemotactic constraint. Initially, this LID system was trained and evaluated for English/Spanish language identification and the language identification was 83% correct (79% on English and 88% on Spanish). Results for four languages w...
1995 International Conference on Acoustics, Speech, and Signal Processing
... (1) When the word labels and the alignment of these ... tory and bigram probabilities since t... more ... (1) When the word labels and the alignment of these ... tory and bigram probabilities since the trigram phonemo-tactic capture the allowable phoneme sequence in any ... For example, the allowable or not allowable three phoneme sequences in English, Spanish and Mandarin are ...
2016 41st International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 2016
Single Pixel Camera Imaging Setup Wave Propagation Model of the SPC Simulation Results References... more Single Pixel Camera Imaging Setup Wave Propagation Model of the SPC Simulation Results References and Acknowledgements Spatially resolved terahertz measurements usually require either mechanical scanning, large and expensive detector arrays, or a combination thereof. So called Single Pixel Cameras (SPCs), consisting mainly of a Spatial Light Modulator (SLM) and a single pixel detector, provide an alternative approach, which has already been demonstrated [1, 2]. For a successful image acquisition, the setup, and especially the behaviour of the SLM, needs to be physically well-understood. A wave propagation model was developed that takes into account the nature of coherent radiation emitted by the THz source. It is capable of predicting signal values at the single pixel detector for a given wavelength, spatial filter configuration, flat object and detector position. The developed model is presented here and verified using a 0.345 THz SPC setup.
Conference of the International Speech Communication Association, 2001
Page 1. Eurospeech 2001 - Scandinavia Using Boosting and POS Word Graph Tagging to Improve Speech... more Page 1. Eurospeech 2001 - Scandinavia Using Boosting and POS Word Graph Tagging to Improve Speech Recognition Christer Samuelsson 1 and James L. Hieronymus 2 ... Morgan Kaufmann. [Manning & Carpenter 1997] Christopher Manning and Bob Carpenter. 1997. ...
Coarticulation alters the vowel formant characteristics in continuous speech. Studies of isolated... more Coarticulation alters the vowel formant characteristics in continuous speech. Studies of isolated monosyllables in the literature suggest that some phonemes cause more severe distortions than others. The largest changes are caused by lrl, Ill, lwl. Unstressed vowels are most affected. Previous studies by Holmes [6] and by us [14] indicate that these effects are even larger for continuous speech. Vowel recognition algorithms which do not take context into account in continuous speech normally achieve correct recognition of approximately 75 % for the three top choices from the recognizer, with the first choice approximately 60 %.. By developing methods which explicitly model the phonetic context, higher levels of performance can to be achieved. An ongoing study is being made of all 16 of the American English vowels using subsets of the DARPA acoustic-phonetic data base. Formants are obtained and normalized for each talkers formant range based on one sentence. The resulting formant tra...
International Conference on Acoustics, Speech, and Signal Processing
An ongoing study is reported of all sixteen of the American English vowels using subsets of the D... more An ongoing study is reported of all sixteen of the American English vowels using subsets of the DARPA acoustic-phonetic database. Formants are obtained and normalized for each talker's formant range based on one sentence. The resulting formant tracks are smoothed using splines and sampled at nine equally spaced points in time within vowel-centered triphone regions. Triphones with semivowels in them are clustered separately. These formant values are k-means clustered using subsets of the sampled formant values. The additional supervised training is done using other parameters, including duration. The resulting clusters are used as a classifier on the basis of the modified Euclidean distance from the cluster centers. This results in approximately 80% first choice vowel recognition of the outer edges of the vowel quadrilateral. Stressed vowels were found to have spectra which statistically were no more stable than unstressed vowels.<<ETX>>
New missions of space exploration will require unprecedented levels of autonomy to successfully a... more New missions of space exploration will require unprecedented levels of autonomy to successfully accomplish their objectives. Both inherent complexity and communication distances will preclude levels of human involvement common to current and previous space flight missions. With exponentially increasing capabilities of computer hardware and software, including networks and communication systems, a new balance of work is being developed between humans
2015 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2015
This paper investigates a weighted finite state transducer (WFST) based syllable decoding and tra... more This paper investigates a weighted finite state transducer (WFST) based syllable decoding and transduction method for keyword search (KWS), and compares it with sub-word search and phone confusion methods in detail. Acoustic context dependent phone models are trained from word forced alignments and then used for syllable decoding and lattice generation. Out-of-vocabulary (OOV) keyword pronunciations are produced using a grapheme-to-syllable (G2S) system and then used to construct a lexical transducer. The lexical transducer is then composed with a keyword-boosted language model (LM) to transduce the syllable lattices to word lattices for final KWS. Word Error Rates (WER) and KWS results are reported for 5 different languages. It is shown that the syllable transduction method gives comparable KWS results to the syllable search and phone confusion methods. Combination of these three methods further improves OOV KWS performance.
The Journal of the Acoustical Society of America, 2008
Research was conducted to examine interactions between acoustic signals and mechanical factors re... more Research was conducted to examine interactions between acoustic signals and mechanical factors relevant to the design of improved auditory displays and noise mitigation for future NASA Spacesuits. Data were collected at NASA Johnson Space Center for the current Mark III advanced prototype surface suit during walking, walking with arm motion, and while seated. Measurements were made using multiple microphones (both head mounted and helmet mounted) and a tri-axial accelerometer to evaluate the effects of suit-borne vibration on overall background noise. Footfall impacts were found to create temporary depolarization of condenser microphone signals, and microphone positioning had a strong effect on signal-noise ratio, partially due to the effect of the helmet enclosure. The results indicate noise mitigation and signal conditioning strategies for improving lunar suit audio voice communications under extra-vehicular (EVA) conditions. Funded by a directed research program of NASA's Spa...
The Journal of the Acoustical Society of America, 1986
The goal is to develop a speaker-independent, semivowel detector-classifier for use with continuo... more The goal is to develop a speaker-independent, semivowel detector-classifier for use with continuous speech. Preliminary analysis of semivowels within continuous speech indicates large within-(and between) speaker variability in the respective semivowel formant frequencies, amplitudes, and durations of steady states and transitions. Deviations from textbook descriptions based on isolated words are significant. Coarticulation effects are also large. Nevertheless, through the use of energy, energy ratios, zero crossings, and signal envelopes, a logical analytical scheme was developed that classifies segments of continuous speech as: semivowel, high-front vowel, vowel, nasal, fricative, stop, or plosive. The specific characteristics of this scheme will be discussed and the computer-generated displays that were used will be presented. Results of using this scheme on a large corpus of phonetically labeled speech will be presented. [Work supported, in part, by DARPA.]
The Journal of the Acoustical Society of America, 1984
Early results on synthetic-vowel formant amplitude discrimination by Flanagan [J. Acoust. Soc. Am... more Early results on synthetic-vowel formant amplitude discrimination by Flanagan [J. Acoust. Soc. Am. 27, 1223–1225 (1955); J. Speech Hear. Disord. 22, 205–212 (1957)] indicated that ΔI for overall vowel level was about ± 1.5 dB, but that ΔI for F2 was about ± 4 dB. The latter result was for F2 ≃ − 12dB re: F1 for the “comparison” vowel. Subjects made a same-different judgment which may have affected the interpretation of these results. Here we report ΔI for several “comparison” vowels which differ in amplitude relations among F1, F2, and F3. In addition, we report on perception of extreme shifts in formant amplitude, Implications for computer recognition of speech will be discussed.
The Journal of the Acoustical Society of America, 1994
A language identification (LID) system that uses phonemotactic models in addition to phoneme mode... more A language identification (LID) system that uses phonemotactic models in addition to phoneme models to identify languages is described. The proposed LID system is trained and tested using the OGI multilanguage telephone speech database. The continuous density second-order ergodic variable duration hidden Markov phonemic models are trained for each language using a high accuracy phoneme recognition system developed at Bell Laboratories. The phonemotactic models for each language are trained using a text corpora of about ten million words and grapheme to phoneme converters. The language Li of an incoming speech signal x is hypothesized as the one that produced the highest likelihood f(x‖λi)f(λi‖Li) for all the phonemic models λi of a given set with the phonemotactic constraint. Initially, this LID system was trained and evaluated for English/Spanish language identification and the language identification was 83% correct (79% on English and 88% on Spanish). Results for four languages w...
1995 International Conference on Acoustics, Speech, and Signal Processing
... (1) When the word labels and the alignment of these ... tory and bigram probabilities since t... more ... (1) When the word labels and the alignment of these ... tory and bigram probabilities since the trigram phonemo-tactic capture the allowable phoneme sequence in any ... For example, the allowable or not allowable three phoneme sequences in English, Spanish and Mandarin are ...
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Papers by Jim Hieronymus