• Title/Summary/Keyword: time scale modification

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Variable Time-Scale Modification with Voiced/Unvoiced Decision (유/무성음 결정에 다른 가변적인 시간축 변환)

  • 손단영;김원구;윤대희;차일환
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.32B no.5
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    • pp.788-797
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    • 1995
  • In this paper, a variable time-scale modification using SOLA(Synchronized OverLap and Add) is proposed, which takes into consideration the different time-scaled characteristics of voiced and unvoiced speech, Generally, voiced speech is subject to higher variations in length during time-scale modification than unvoiced speech, but the conventional method performs time-scale modification at a uniform rate for all speech. For this purpose, voiced and unvoiced speech duration at various talking speeds were statistically analyzed. The sentences were then spoken at rates of 0.7, 1.3, 1.5 and 1.8 times normal speed. A clipping autocorrelation function was applied to each analysis frame to determine voiced and unvoiced speech to obtain respective variation rates. The results were used to perform variable time-scale modification to produce sentences at rates of 0.7, 1.3, 1.5, 1.8 times normal speed. To evaluate performance, a MOS test was conducted to compare the proposed voiced/unvoiced variable time-scale modification and the uniform SOLA method. Results indicate that the proposed method produces sentence quality superior to that of the conventional method.

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Variable Time-Scale Modification of Speech Using Transient Information based on LPC Cepstral Distance (LPC 켑스트럼 거리 기반의 천이구간 정보를 이용한 음성의 가변적인 시간축 변환)

  • Lee, Sung-Joo;Kim, Hee-Dong;Kim, Hyung-Soon
    • Speech Sciences
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    • v.3
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    • pp.167-176
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    • 1998
  • Conventional time-scale modification methods have the problem that as the modification rate gets higher the time-scale modified speech signal becomes less intelligible, because they ignore the effect of articulation rate on speech characteristics. Results of research on speech perception show that the timing information of transient portions of a speech signal plays an important role in discriminating among different speech sounds. Inspired by this fact, we propose a novel scheme for modifying the time-scale of speech. In the proposed scheme, the timing information of the transient portions of speech is preserved, while the steady portions of speech are compressed or expanded somewhat excessively for maintaining overall time-scale change. In order to identify the transient and steady portions of a speech signal, we employ a simple method using LPC cepstral distance between neighboring frames. The result of the subjective preference test indicates that the proposed method produces performance superior to that of the conventional SOLA method, especially for very fast playback case.

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Variable Time-Scale Modification with Voiced/Unvoiced Decision (유/무성음 결정에 따른 가변적인 시간축 변환)

  • 손단영
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1994.06c
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    • pp.111-115
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    • 1994
  • In this paper, a variable time-scale modification using SOLA is proposed, which takes into consideration the different time-scaled characteristics of voiced and unvoiced speech. The conventional method performs time-scale modifiction at a uniform rate for all speech. For this purpose, voiced and unvoiced speech duration at various taling speeds were statistically analyzed. A clipping autocorrelation functio was applied to each analysis frame to detemine voiced and unvoiced speech to obtain respective variation rates. The results were used to perform variable time-scale modification to evaluate performance, a MOS test was conducted to compare the proposed voiced/unvoiced variable time-scale modification and the uniform SOLA method. Results indicate that the proposed method produces sentence quality superior to that of the conventional method.

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Variable Time-Scale Modification of Speech Using Trasient Information (천이구간 정보를 이용한 음성의 가변적인 시간축 변환)

  • Lee, Sung-Joo;Kim, Hee-Dong;Kim, Hyung-Soon
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.35S no.6
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    • pp.147-155
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    • 1998
  • Conventional time-scale modification methods have the problem that as the modification rate gets higher the time-scale modified speech signal becomes less intelligible, because they ignore the effect of articulation rate on speech characteristics. In this paper, we propose a variable time-scale modification method based on the knowledge that the timing information of transient portions of a speech signal plays an important role in speech perception. After identifying steady protions only. The result of subjective preference test indicates that the proposed method produces performance superior to that of the conventional SOLA method.

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Optimized Time Scale Modification (TSM) System Integrating G,729 Speech Decoder and Dual SOLA Algorithm (G.729 음성 복호화기와 듀얼 SOLA 알고리즘을 통합한 최적의 음성 속도 변환 시스템)

  • 박규식;오승록;김선영
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.3
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    • pp.293-303
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    • 2002
  • This paper implements optimized Time Scale Modification (TSM) system using ITU G.729 speech decoder and Dual SOLA algorithm. The proposed system assume 8 Kz sampling rate, 80 samples/frame input speech from the ITU G.729 speech Decoder and the TSM (Time Scale Modification) feature of Dual SOLA produces the high quality output speech that was slow-down or speed up as a user's choice. Especially, the proposed Optimized Dual SOLA base on various simulations and theoretical analysis, and the additional interpolation procedure of the speech makes it possible to setup high performance integrated TSM system at the maximum time scale modification rate. The system performance is analyzed and verified with various input speech and playback speed.

Concealment of Internet Packet Loss Using Time Scale Modification (Time Scale Modification 을 이용한 인터넷 패킷 손실의 보상)

  • Oh Yoon Haak;Hur Ho Young;Kim Hee Dong;Jeon Jun Hyun;Kim Hyung Soon
    • Proceedings of the Acoustical Society of Korea Conference
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    • autumn
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    • pp.45-48
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    • 1999
  • 인터넷에서 전송 지연에 의해 발생한 패킷 손실은 인터넷이라는 공유망을 사용함으로써 불가피하게 발생하게 된다. 이러한 패킷 손실은 음성과 같이 실시간 처리가 필요한 미디어를 전송할 경우 매우 심각한 문제를 야기시킨다. 본 논문에서는 인터넷을 통한 음성통신에서 전송 지연으로 인해 발생한 패킷 손실을 time scale modification(TSM)기번을 이동하여 복원하는 방법들을 검토하였다. 청취평가 결과, 송수신단 양쪽에서 TSM을 적용할 경우 기존의 가장 우수한 접근방식인 재생성(regeneration) 방식과 거의 대등한 음질을 얻을 수 있다.

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Fast Time-Scale Modification of Speech Using Nonlinear Clipping Methods

  • Jung, Ho-Young;Kim, Hyung-Soon;Lee, Sung-Joo
    • MALSORI
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    • no.59
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    • pp.69-87
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    • 2006
  • Among the conventional time-scale modification (TSM) methods, the synchronized overlap and add (SOLA) method is widely used due to its good performance relative to computational complexity But the SOLA method remains complex due to its synchronization procedure using the normalized cross-correlation function. In this paper, we introduce a computationally efficient SOLA method utilizing 3 level center clipping method, as well as zero-crossing and level-crossing information. The result of subjective preference test indicates that the proposed method can reduce the computational complexity by over 80% compared with the conventional SOLA method without serious degradation of synthesized speech quality.

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A Study on Real-time Implementing of Time-Scale Modification (음성 신호 시간축 변환의 실시간 구현에 관한 연구)

  • Han, Dong-Chul;Lee, Ki-Seung;Cha, Il-Hawan;Youn, Dae-Hee
    • The Journal of the Acoustical Society of Korea
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    • v.14 no.2
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    • pp.50-61
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    • 1995
  • A time scale modification method yielding rate-modified speech while conserving the characteristic of speech was implemented in real-time using a goneral purpose digital signal processor. Time scale modification changed pronunciation speed only, producing a time difference between the input signal and the modified signal, making it impossible to implement it in real-time. In this thesis, a system was implemented to remove the time difference between the input and modified signals. Speech signals slowed down or speeded up by a physical time scale modification method, such as adjusting the motor speed of the cassett tape recorder, was used as the input signal. Physical modification that controled only the inter speed of the cassette tape player distorted the pitch period of the original speech. In this study, a real-time system was implemented so that the pitch-distorted speech was reconstructed back to the original by fractional sampling pitch shifting using an FIR filter, and this signal was time scale modified to match the cassette tape recorder motor speed using SOLA time-scale medification. In experiments using speech signals medifiedby the proposed method, results obtained using a 16-bit resolution ADSP2101 processor and using computer simulations employing floating point operations showed about the same average frame signal-to-noise ratio of about 20 dB.

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Time-Scale Modification of Polyphonic Audio Signals Using Sinusoidal Modeling (정현파 모델링을 이용한 폴리포닉 오디오 신호의 시간축 변화)

  • 장호근;박주성
    • The Journal of the Acoustical Society of Korea
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    • v.20 no.2
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    • pp.77-85
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    • 2001
  • This paper proposes a method of time-scale modification of polyphonic audio signals based on a sinusoidal model. The signals are modeled with sinusoidal component and noise component. A multiresolution filter bank is designed which splits the input signal into six octave-spaced subbands without aliasing and sinusoidal modeling is applied to each subband signal. To alleviate smearing of transients in time-scale modification a dynamic segmentation method is applied to subbands which determines the analysis-synthesis frame size adaptively to fit time-frequency characteristics of the subband signal. For extracting sinusoidal components and calculating their parameters matching pursuit algorithm is applied to each analysis frame of subband signal. In accordance with spectrum analysis a psychoacoustic model implementing the effect of frequency masking is incorporated with matching pursuit to provide a resonable stop condition of iteration and reduce the number of sinusoids. The noise component obtained by subtracting the synthesized signal with sinusoidal components from the original signal is modeled by line-segment model of short time spectrum envelope. For various polyphonic audio signals the result of simulation shows suggested sinusoidal modeling can synthesize original signal without loss of perceptual quality and do more robust and high quality time-scale modification for large scale factor because of representing transients without any perceptual loss.

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A Fast Normalized Cross-Correlation Computation for WSOLA-based Speech Time-Scale Modification (WSOLA 기반의 음성 시간축 변환을 위한 고속의 정규상호상관도 계산)

  • Lim, Sangjun;Kim, Hyung Soon
    • The Journal of the Acoustical Society of Korea
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    • v.31 no.7
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    • pp.427-434
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    • 2012
  • The overlap-add technique based on waveform similarity (WSOLA) method is known to be an efficient high-quality algorithm for time scaling of speech signal. The computational load of WSOLA is concentrated on the repeated normalized cross-correlation (NCC) calculation to evaluate the similarity between two signal waveforms. To reduce the computational complexity of WSOLA, this paper proposes a fast NCC computation method, in which NCC is obtained through pre-calculated sum tables to eliminate redundancy of repeated NCC calculations in the adjacent regions. While the denominator part of NCC has much redundancy irrespective of the time-scale factor, the numerator part of NCC has less redundancy and the amount of redundancy is dependent on both the time-scale factor and optimal shift value, thereby requiring more sophisticated algorithm for fast computation. The simulation results show that the proposed method reduces about 40%, 47% and 52% of the WSOLA execution time for the time-scale compression, 2 and 3 times time-scale expansions, respectively, while maintaining exactly the same speech quality of the conventional WSOLA.