• 제목/요약/키워드: Wavelet transform

검색결과 2,201건 처리시간 0.024초

On Wavelet Transform Based Feature Extraction for Speech Recognition Application

  • Kim, Jae-Gil
    • The Journal of the Acoustical Society of Korea
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    • 제17권2E호
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    • pp.31-37
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    • 1998
  • This paper proposes a feature extraction method using wavelet transform for speech recognition. Speech recognition system generally carries out the recognition task based on speech features which are usually obtained via time-frequency representations such as Short-Time Fourier Transform (STFT) and Linear Predictive Coding(LPC). In some respects these methods may not be suitable for representing highly complex speech characteristics. They map the speech features with same may not frequency resolutions at all frequencies. Wavelet transform overcomes some of these limitations. Wavelet transform captures signal with fine time resolutions at high frequencies and fine frequency resolutions at low frequencies, which may present a significant advantage when analyzing highly localized speech events. Based on this motivation, this paper investigates the effectiveness of wavelet transform for feature extraction of wavelet transform for feature extraction focused on enhancing speech recognition. The proposed method is implemented using Sampled Continuous Wavelet Transform (SCWT) and its performance is tested on a speaker-independent isolated word recognizer that discerns 50 Korean words. In particular, the effect of mother wavelet employed and number of voices per octave on the performance of proposed method is investigated. Also the influence on the size of mother wavelet on the performance of proposed method is discussed. Throughout the experiments, the performance of proposed method is discussed. Throughout the experiments, the performance of proposed method is compared with the most prevalent conventional method, MFCC (Mel0frequency Cepstral Coefficient). The experiments show that the recognition performance of the proposed method is better than that of MFCC. But the improvement is marginal while, due to the dimensionality increase, the computational loads of proposed method is substantially greater than that of MFCC.

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이중 밀도 웨이브렛 변환의 성능 향상을 위한 3방향 분리 처리 기법 (The Three Directional Separable Processing Method for Double-Density Wavelet Transformation Improvement)

  • 신종홍
    • 디지털산업정보학회논문지
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    • 제8권2호
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    • pp.131-143
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    • 2012
  • This paper introduces the double-density discrete wavelet transform using 3 direction separable processing method, which is a discrete wavelet transform that combines the double-density discrete wavelet transform and quincunx sampling method, each of which has its own characteristics and advantages. The double-density discrete wavelet transform is nearly shift-invariant. But there is room for improvement because not all of the wavelets are directional. That is, although the double-density DWT utilizes more wavelets, some lack a dominant spatial orientation, which prevents them from being able to isolate those directions. The dual-tree discrete wavelet transform has a more computationally efficient approach to shift invariance. Also, the dual-tree discrete wavelet transform gives much better directional selectivity when filtering multidimensional signals. But this transformation has more cost complexity Because it needs eight digital filters. Therefor, we need to hybrid transform which has the more directional selection and the lower cost complexity. A solution to this problem is a the double-density discrete wavelet transform using 3 direction separable processing method. The proposed wavelet transformation services good performance in image and video processing fields.

이산 웨이블렛 변환을 이용한 자유감쇠 횡요 데이타의 분리 (Decoupling of Free Decay Roll Data by Discrete Wavelet Transform)

  • Kwon, Sun-Hong;Lee, Hee-Sung;Lee, Hyoung-Suk;Ha, Mun-Keun
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2001년도 추계학술대회 논문집
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    • pp.169-173
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    • 2001
  • This study presents the results of decoupling of free decay roll test data by discrete wavelet transform. Free roll decay test was performed to decide the coefficients of damping terms in equation of motion. During the experiment, a slight yaw motion was found while the model was in the free roll decay motion. Discrete wavelet transform was applied to the signal to extract the pure roll motion. The results were compared to those of the Fourier transform. DWT was able to decouple the two signals efficiently while the Fourier transform was not.

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A Study on the Performance of the Watermarking with Wavelet Transform

  • Kang, Hwan-Il;Park, Hwan-soo
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제1권1호
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    • pp.24-28
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    • 2001
  • Wavelet transforms are used for implementing digital watermarking methods in the frequency domain. In this paper, we construct the digital watermarking using various wavelet transforms such as the Daubechies transform, Coiflets transform, Symlets transform and the biorthogonal transform, and we compare each digital watermarking method with the others. We investigate the preservation of the watermark after the data compression attack based on the discrete on the discrete cosine transform. We show that the biorthogonal wavelet, denoted by bior3.5, has the best performance among the wavelet types we selected in an experiment.

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웨이브렛 변환을 이용한 전자빔 용접 진단 (Electron Beam Welding Diagnosis Using Wavelet Transform)

  • 윤충섭
    • Journal of Welding and Joining
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    • 제21권6호
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    • pp.33-39
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    • 2003
  • Wavelet transform analysis results show a spectrum energy distribution of CWT along scale factors distinguish the partial, full and over penetration in a electron beam welding by analyzing the curve of spectrum energy at small scale, middle and large scale range, respectively. Two types of signals collected by Ion collector and x-ray sensors and analyzed. The acquired signals from sensors are very complicated since these signals are very closely related the dynamics of keyhole which interact the very high density energy with materials during welding. The results show the wavelet transform is more effective to diagnosis than Fourier Transform, further for the general welding defects which are not a periodic based, but a transient, non-stationary and time-varying phenomena.

이산 웨이블릿 변환을 이용한 지문의 계층적 분류 (Hierarchical classification of Fingerprints using Discrete Wavelet Transform)

  • 권용호;이정문
    • 산업기술연구
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    • 제19권
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    • pp.403-408
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    • 1999
  • An efficient method is developed for classifying fingerprint data based on 2-D discrete wavelet transform. Fingerprint data is first converted to a binary image. Then a multi-level 2-D wavelet transform is performed. Vertical and horizontal subbands of the transformed data show typical energy distribution patterns relevant to the fingerprint categories. The proposed method with moderate level of wavelet transform is successful in classifying fingerprints into 5 different types. Finer classification is possible by higher frequency subbands and closer analysis of energy distribution.

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Wavelet transform을 이용한 GIS내 초음파 신호 분석 (Analysis of Ultrasonic signal in GIS using Wavelet transform)

  • 이동준;곽희로;박중신;김두석
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 하계학술대회 논문집 C
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    • pp.1918-1920
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    • 2000
  • In this paper, acoustic signals in GIS were analyzed by using wavelet transform and FFT to distinguish sound source caused by collision of particles and partial discharges. As a result, the analysis using wavelet transform was more accurate than that using FFT. Therefore, wavelet transform was useful technique to analyze the acoustic signals in GIS.

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웨이블릿 변환역 최소평균자승법을 이용한 능동 소음 제어 (Active Noise Control Using Wavelet Transform Domain Least Mean Square)

  • 김도형;박영진
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 춘계학술대회논문집
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    • pp.269-273
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    • 2000
  • This paper describes Active Noise Control (ANC) using Discrete Wavelet Transform (DWT) Domain Least Mean Square (LMS) Method. DWT-LMS is one of the transform domain input decorrelation LMS and improves the convergence speed of adaptive filter especially when the input signal is highly correlated. Conventional transform domain LMS's use Discrete Cosine Transform (DCT) because it offers linear band signal decomposition and fast transform algorithm. Wavelet transform can project the input signal into the several octave band subspace and offers more efficient sliding fast transform algorithm. In this paper, we propose Wavelet transform domain LMS algorithm and shows its performance is similar to DCT LMS in some cases using ANC simulation.

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스파이크 웨이블렛 변환을 이용한 기어 시스템의 건전성 감시 (Condition Monitoring in Gear System Using Spike Wavelet Transform)

  • 이상권;심장선
    • 한국음향학회지
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    • 제20권5호
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    • pp.21-27
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    • 2001
  • 기어 시스템의 충격음과 충격 신호는 대개 기어의 결함과 관련이 있다. 그래서 이러한 충격음과 충격 신호는 기어 시스템의 건전성 감시의 주요 요소로 사용되어진다. 본 연구에서는 이런 충격음과 충격 신호를 효율적으로 추출해 내기 위해 스파이크 웨이블렛 변환을 이용하는 방법을 제안한다. 스파이크 웨이블렛 변환은 기존에 제안된 연속 웨이블렛 변환의 한계점인 임의의 영역에서의 시간-주파수 분해능의 스케일 변수에 대한 선형성을 보완하여 비 선형적으로 이것을 조절할 수 있게 하였다. 이로 인해서 스파이크 웨이블렛 변환은 관심 주파수를 기준으로 연속 웨이블렛 변환보다 고주파 영역에서는 시간 분해능이 향상되고 동시에 저주파 영역에서는 주파수 분해능이 향상되어 기어 결함에 대한 정보 손실 없이 기어의 결함 위치를 보다 명확히 판단할 수 있는 장점을 가진다. 또한 본 연구에서는 상단 절손의 결함을 갖는 기어에 대한 실험을 통해 본 연구에서 제안하는 스파이크 웨이블렛 변환의 유용성을 검증하였다.

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리프팅 기반의 3차원 웨이블릿 변환 인코더의 아키텍쳐 설계 (Architecture Design of 3D-Wavelet Transform encoder based on Lifting Scheme)

  • 조덕은;송낙운
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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    • pp.409-412
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    • 2003
  • In this paper, the encoder architecture of 3-D wavelet transform based on lifting scheme is designed. Architecture, here, 3 level wavelet transform for spatial decomposition and 2 level wavelet transform for temporal decomposition is adopted with efficient computation.

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