• Phonetics and Speech Sciences
• /
• v.1 no.3
• /
• pp.65-72
• /
• 2009

Formant values are the most important acoustic correlates of English vowels. Classical studies on English vowels reported the first three formant values measured at a single timepoint on a sustained vowel segment. However, many recent studies revealed that partial onset or offset segments with information of dynamic spectral changes may contribute to the exact identification of English vowels with an accuracy almost comparable to that by the whole vowel segment or word. The purpose of this study was to examine formant trajectories of nine English vowels collected by Hillenbrand et al.(1995). Acoustic analysis was systematically made by a Praat script at six equidistant timepoints over the vowel segment. Results showed that the first formant trajectories played an important role in distinguishing each vowel within the front- or back-vowel groups. The second formant trajectories of the back vowels varied more drastically than those of the front vowels. The third formant value was similar except the high vowel /i/. From the vowel space on F1 by F2 axes, the formant trajectories of each vowel clearly showed a transition toward the locus of the following consonant /d/. Other acoustic data revealed that there were some vowel inherent duration or pitch values. From this study we can conclude that the dynamic spectral changes are very important in specifying acoustic characteristics of the English vowels. Further studies on vowels and diphthongs in different contexts are desirable.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.4
• /
• pp.715-720
• /
• 2017

This study tries to analyze morphology and formant frequencies of linear prediction spectra of stethoscope sounds for heart diseased children. For this object, heart diseased stethoscope sounds were collected in the pediatrics of an university hospital. The collected signals were preprocessed and analyzed by the Burg algorithm, a kind of linear prediction analysis. The linear prediction spectra and the formant frequencies of the spectra for the stethoscope sounds for the normal and the diseased children are estimated and compared. The spectra showed outstanding differences in morphology and formant frequencies between the normal and the diseased children. Normal children showed relatively low frequency of F1(the first formant) and small negative slope from F1. VSD children revealed stiff slope change around F1 to F3. Spectra of ASD children is similar with the normal case, but have negative values of F3. F1-F2 difference of the functional murmur children were relatively large.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.17 no.3
• /
• pp.12-19
• /
• 1980

A speech recognition system for separately pronounced Korean digits is described. The system is composed of four stages ; parameter extraction, segmentation by voiced-unovied analysis, formant tracking and pattern matching. Digit speech is segmented into an unvoiced segment and/or a voiced one using ZCR and energy measurements, then to estimate the first three formant frequencies a relatively simple formant tracking scheme is applied to the raw formant data extracted from linear prediction spectra. Finally, pattern matching is made using dynamic programmig method. Recognition experiment is carried out for 150 digit utterences spoken by three male speakers, and recgnition rate 94 % is obtained.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.11
• /
• pp.1605-1610
• /
• 2015

This study describes a new method to analyze phonocardiogram acquired from electronic stethoscope. The method uses the formant frequencies of linear prediction spectrum of the phonocardiogram and proposes a novel method for formant detection using the smoothing and the first and second derivatives. For this, stethoscope sounds are acquired in university hospital. The stethoscope signals are preprocessed and analyzed by the Burg algorithm, a kind of linear prediction analysis. Based on the linear prediction spectra, the formant frequencies are estimated. The proposed method has shown better performance in formant frequency detection than the conventional peak picking method.

• Phonetics and Speech Sciences
• /
• v.6 no.2
• /
• pp.55-64
• /
• 2014

This study measured formant bandwidths of profound hearing impaired children and examined the characteristics of their articulation. For this study, 10 cochlear implanted children(CI), 10 hearing aid children(HA) and 10 normal hearing children(NH) were asked to read 7 Korean vowels(/ɑ, ʌ, o, u, ɯ, i, ɛ/). The subjects' readings were recorded by NasalView and analyzed by Praat. The analysis of the formant bandwidths explains the degree of vocal fold opening and the characteristics of radiation. Through the analysis of formant bandwidth, we can see that the hearing-impaired maintain vocal fold tension when they speak high vowels and characteristics of radiation. Narrower B1 means better maintain vocal fold tension, wider B2 means more front and wider B3 means the rounder lips. CI's B1 was widest and NH's was narrowest. And females' B1 was wider than males'. Among vowels, B1 of /a/ was widest, and B1 of /i/ was narrowest. In the case of B2, HA and NH's B2 was wider than CI's. Females' B2 was wider than males'. And B2 of /i/ was widest, and B2 of /ʌ/ was narrowest. In the case of B3, NH's was widest, and CI's was narrowest. Males' was wider than females'. Among vowels, B3 of /o/ was widest, and B3 of /ɛ/ was narrowest. As a result, first, through the analysis of B1, we can find that NH and males could better maintain vocal fold tension than the hearing-impaired or females, and all children articulate /i/ with vocal fold tension than other vowels. Second, through the analysis of B2, NH and HA articulate vowels with the weaker rounded than CI does. And females articulate vowels with the weaker rounded than males do. Third, through the analysis of B3, NH articulate vowels with the rounder than HA or CI do, and males articulate vowels with the rounder than females do. Through the results, we can expect that the analysis of formant bandwidth will be applied to the therapy of articulation for the hearing-impaired with hearing aids or cochlear implant.

• Proceedings of the Acoustical Society of Korea Conference
• /
• spring
• /
• pp.325-328
• /
• 2000

According to H.B.Lee(1993), standard Korean vowel qualities are as follows: in /i/, /e/, $/\epsilon/$, /a/, /o/, /w/, they have 4 qualities each other and in /er/ there are 3 qualities. The environments of 4 qualities are iong and stressed vowel in word initial, short and stressed vowel in word initial, unstressed vowel in word initial, unstressed vowel in word finial. The aim of this study is to seek and compare with H.B.Lee(1993). Conclusively I could not find on the whole any pattern of the same types of H.B.Lee(1993) in this study And especially in Fl vowel formant values of /er/and /w/, I never found any pattern of the same types of H.B.Lee(1993). Also F2 vowel formant values of $/\varepsilon/$ and /w/ do not have any kind of pattern of the same types of H.B.Lee(1993), between them, the patternize of F2 vowel formant values in /w / is especially difficult. It is the same story of Jaekang Lee(1998). But in some case, the patternize could be done. among the whole vowels, analysis environment b has the wide width on the change of the formant value. As the another result of the analysis It is to possible to make the pattern of the old male group. The old male group on the whole is analyzed to have the most low formant values and the old women group is analyzed to have the most high formants values, but in the most high formant valus there are young women group. And the formant values's rising in 2 cases of the formant value of /er/ is analyzed to have the same pattern of H.B.Lee(1993).

• Journal of the Ergonomics Society of Korea
• /
• v.32 no.1
• /
• pp.139-144
• /
• 2013

Objective: The current study investigated a non-obtrusive measure for detecting physical fatigue based on the analysis of formant frequencies of human voice. Background: Fatigue has been considered as a main cause in industrial and traffic accidents. Therefore, it is critical to detect worker's fatigue for accident prevention. Method: After running exercises on a treadmill, participants were instructed to read a sentence and their voices were recorded under four different physical fatigue levels. Korean vowels of "아", "어", "오", "우", and "이" from the voice recorded were then used to collect formant 1 frequencies. Results: Results of separate ANOVAs showed a significant main effect of physical fatigue on formant 1 frequency of "아", "어", and "이". Furthermore, post-hoc comparisons revealed that formant 1 frequency of "아" was most sensitive to physical fatigue level employed in this experiment. Conclusion: Formant 1 frequencies of some vowels significantly decrease as the physical fatigue level increases. Application: Potential application of this study includes the development of a measure of physical fatigue state that is free from sensor attachment and requires little preparation.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.4
• /
• pp.805-810
• /
• 2009

This paper present a characteristic of formant variation in order to discriminate between drinking and nondrinking condition. By simulation experiments based on monosyllable, it is shown that the higher formant in F1, F2 and F3 in drinking speech signals compared with nondrinking speech signals. And I knew that the formant is very effective at distinction of drinking condition and nondrinking condition.

• MALSORI
• /
• no.57
• /
• pp.43-58
• /
• 2006

This study aims to investigate whether Chinese learning Korean and Korean native speakers show any difference in length and formant structures of the Korean liquid 'ㄹ' in the environments of v_v and v_# through the acoustic analysis of 10 Chinese learners' and 10 Koreans' utterances. The acoustic analysis of L2KSC DB shows that the length and formant structures of 'ㄹ' produced by Chinese learners are significantly different from the ones by Koreans. I explain these differences by contrasting the liquids and syllable structure constraints of the two languages, Chinese and Korean. In addition, I relate the F1 and F2's values to the tongue's movement when making a constriction, and conclude that Chinese learners pronounce the 'ㄹ' in the v_# environment with the tongue lower and backer than Koreans do.

• Speech Sciences
• /
• v.10 no.2
• /
• pp.85-95
• /
• 2003

In speech signal processing, it is very important to detect the pitch exactly in speech recognition, synthesis and analysis. If we exactly pitch detect in speech signal, in the analysis, we can use the pitch to obtain properly the vocal tract parameter. It can be used to easily change or to maintain the naturalness and intelligibility of quality in speech synthesis and to eliminate the personality for speaker-independence in speech recognition. In this paper, we proposed a new pitch detection algorithm. First, positive center clipping is process by using the incline of speech in order to emphasize pitch period with a glottal component of removed vocal tract characteristic in time domain. And rough formant envelope is computed through peak-fitting spectrum of original speech signal infrequence domain. Using the roughed formant envelope, obtain the smoothed formant envelope through calculate the linear interpolation. As well get the flattened harmonics waveform with the algebra difference between spectrum of original speech signal and smoothed formant envelope. Inverse fast fourier transform (IFFT) compute this flattened harmonics. After all, we obtain Residual signal which is removed vocal tract element. The performance was compared with LPC and Cepstrum, ACF. Owing to this algorithm, we have obtained the pitch information improved the accuracy of pitch detection and gross error rate is reduced in voice speech region and in transition region of changing the phoneme.