• Title/Summary/Keyword: Harr Wavelet

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Noise Suppression of NMR Spectrum by Shifted Harr Wavelet Transform

  • Hoshik Won;Kim, Daesung
    • Journal of the Korean Magnetic Resonance Society
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    • v.5 no.2
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    • pp.66-72
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    • 2001
  • The noise suppression of time domain NMR data by discrete wavelet transform with high order Daubechies wavelet coefficients exhibits severe peak distortion and incomplete noise suppression near real signal. However, the fact that even a shift averaged Harr wavelet transform with a set of Daubechies wavelet coefficients (1/2, -l/2) can be used as a new and excellent tool to distinguish real peaks from the noise contaminated NMR signal is introduced. New algorithms of shift averaged Harr wavelet were developed and quantitatively evaluated in terms of threshold and signal to noise ratio (SNR).

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Large Solvent and Noise Peak Suppression by Combined SVD-Harr Wavelet Transform

  • Kim, Dae-Sung;Kim, Dai-Gyoung;Lee, Yong-Woo;Won, Ho-Shik
    • Bulletin of the Korean Chemical Society
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    • v.24 no.7
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    • pp.971-974
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    • 2003
  • By utilizing singular value decomposition (SVD) and shift averaged Harr wavelet transform (WT) with a set of Daubechies wavelet coefficients (1/2, -1/2), a method that can simultaneously eliminate an unwanted large solvent peak and noise peaks from NMR data has been developed. Noise elimination was accomplished by shift-averaging the time domain NMR data after a large solvent peak was suppressed by SVD. The algorithms took advantage of the WT, giving excellent results for the noise elimination in the Gaussian type NMR spectral lines of NMR data pretreated with SVD, providing superb results in the adjustment of phase and magnitude of the spectrum. SVD and shift averaged Haar wavelet methods were quantitatively evaluated in terms of threshold values and signal to noise (S/N) ratio values.

An Experiment on Volume Data Compression and Visualization using Wavelet Transform (웨이블릿 변환을 이용한 볼륨데이타의 압축 및 가시화 실험)

  • 최임석;권오봉;송주환
    • Journal of KIISE:Computing Practices and Letters
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    • v.9 no.6
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    • pp.646-661
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    • 2003
  • It is not easy that we visualize the large volume data stored in the every client computers of the web environment. One solution is as follows. First we compress volume data, second store that in the database server, third transfer that to client computer, fourth visualize that with direct-volume-rendering in the client computer. In this case, we usually use wavelet transform for compressing large data. This paper reports the experiments for acquiring the wavelet bases and the compression ratios fit for the above processing paradigm. In this experiments, we compress the volume data Engine, CThead, Bentum into 50%, 10%, 5%, 1%, 0.1%, 0.03% of the total data respectively using Harr, Daubechies4, Daubechies12 and Daubechies20 wavelets, then visualize that with direct-volume-rendering, afterwards evaluate the images with eyes and image comparison metrics. When compression ratio being low the performance of Harr wavelet is better than the performance of the other wavelets, when compression ratio being high the performance of Daubechies4 and Daubechies12 is better than the performance of the other wavelets. When measuring with eyes the good compression ratio is about 1% of all the data, when measuring with image comparison metrics, the good compression ratio is about 5-10% of all the data.

An Improved Wavelet PWM Technique with Output Voltage Amplitude Control for Single-phase Inverters

  • Zheng, Chun-Fang;Zhang, Bo;Qiu, Dong-Yuan;Zhang, Xiao-Hui;Li, Rui
    • Journal of Power Electronics
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    • v.16 no.4
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    • pp.1407-1414
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    • 2016
  • Unlike existing pulse-width modulation (PWM) techniques, such as sinusoidal PWM and random PWM, the wavelet PWM (WPWM) technique based on a Harr wavelet function can achieve a high fundamental component for the output voltage, low total harmonic distortion, and simple digital implementation. However, the original WPWM method lacks output voltage control. Thus, the practical application of the WPWM technique is limited. This study proposes an improved WPWM technique that can regulate output voltage amplitude with the addition of a parameter. The relationship between the additional parameter and the output voltage amplitude is analyzed in detail. Experimental results verify that the improved WPWM exhibits output voltage control in addition to all the merits of the WPWM technique.

P-wave Detection Using Wavelet Transform (Wavelet Transform을 이용한 P파 검출에 관한 연구)

  • Jang, W.S.;Yoon, Y.R.;Yoon, H.R.
    • Proceedings of the KOSOMBE Conference
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    • v.1996 no.11
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    • pp.377-380
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    • 1996
  • The purpose of this paper is to improve the P-wave detection capacity using wavelet transform. The first procedure is to remove baseline drift using the median filter. The second procedure is to cancel ECG's QRS-T complex with ECG's QRS-T complex templete to get P-wave candidate. Before we cancelled out the QRS-T complex, we estimated the best matching between templete and QRS-T complex to minimize the error. Then, Harr wavelet was used to eleminate the high frequency noise of ECG wave form cancelled the QRS-T complex. Finally, P-wave was discriminated and confirmed by threshold value. By using this method, We can got the around 95.1% P-wave detection.

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A Lossless Image Compression using Wavelet Transform with 9/7 Integer Coefficient Filter Bank (9/7텝을 갖는 정수 웨이브릿 변환을 이용한 무손실 정지영상 압축)

  • 추형석;서영천;이태호;전희성;안종구
    • Proceedings of the Korea Institute of Convergence Signal Processing
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    • 2000.08a
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    • pp.253-256
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    • 2000
  • In this paper, we propose the lossless image compression algorithm using the integer wavelet transform. Recently, the S+P transform is widely used and computed with only integer addition and bit-shift operations, but not proper to remove the correlation of smooth images. then we compare the Harr wavelet of the S+P transform with various integer coefficient filter banks and apply 9/7 ICFB to the wavelet transform. In addition, we propose a entropy-coding method that exploits the multiresolution structure and the feedback of the prediction error, and can efficiently compress the transformed image for progressive transmission. Simulation results are compared to the compression ratio using the S+P transform with different types of images.

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Rotation-invariant pattern recognition using an optical wavelet circular harmonic matched filter (광웨이브렛 원형고조 정합필터를 이용한 회전불변 패턴인식)

  • 이하운;김철수;김정우;김수중
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.1
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    • pp.132-144
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    • 1997
  • The rotation-invariant pattern recognition filter using circular harmonic function of the wavelet transforme dsreference image by morlet, mexican-hat, and haar wavelt function is proposed. The rotated reference images, the images sililar to the reference image, and the images which are added by random noise are used for the inpt images, and in case of the input images with random noise, they are applied to the recognition after removing the random noise by the transformed moving average method with proper thresholding value and window size. The proposed optical wavelet circular harmonic matched filter (WCHMF) is a type of the matche dfilter, so that it can be applied to the 4f vander lugt optical correlation system. SNR and discrimination capability of the proposed filter are compared with those of the conventional HF, the POCHF, and the BPOCHF. The proper wavelet function for the reference image used in this paper is achieved by applying morlet, mexican-hat, and harr wavelet function ot the proposed filter, and the proposed filter has good SNR and discrimination capability with rotation-invariance in case of the morlet wavelet function.

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Real-Time Head Tracking using Adaptive Boosting in Surveillance (서베일런스에서 Adaptive Boosting을 이용한 실시간 헤드 트래킹)

  • Kang, Sung-Kwan;Lee, Jung-Hyun
    • Journal of Digital Convergence
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    • v.11 no.2
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    • pp.243-248
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    • 2013
  • This paper proposes an effective method using Adaptive Boosting to track a person's head in complex background. By only one way to feature extraction methods are not sufficient for modeling a person's head. Therefore, the method proposed in this paper, several feature extraction methods for the accuracy of the detection head running at the same time. Feature Extraction for the imaging of the head was extracted using sub-region and Haar wavelet transform. Sub-region represents the local characteristics of the head, Haar wavelet transform can indicate the frequency characteristics of face. Therefore, if we use them to extract the features of face, effective modeling is possible. In the proposed method to track down the man's head from the input video in real time, we ues the results after learning Harr-wavelet characteristics of the three types using AdaBoosting algorithm. Originally the AdaBoosting algorithm, there is a very long learning time, if learning data was changes, and then it is need to be performed learning again. In order to overcome this shortcoming, in this research propose efficient method using cascade AdaBoosting. This method reduces the learning time for the imaging of the head, and can respond effectively to changes in the learning data. The proposed method generated classifier with excellent performance using less learning time and learning data. In addition, this method accurately detect and track head of person from a variety of head data in real-time video images.

The Facial Area Extraction Using Multi-Channel Skin Color Model and The Facial Recognition Using Efficient Feature Vectors (Multi-Channel 피부색 모델을 이용한 얼굴영역추출과 효율적인 특징벡터를 이용한 얼굴 인식)

  • Choi Gwang-Mi;Kim Hyeong-Gyun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.9 no.7
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    • pp.1513-1517
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    • 2005
  • In this paper, I make use of a Multi-Channel skin color model with Hue, Cb, Cg using Red, Blue, Green channel altogether which remove bight component as being consider the characteristics of skin color to do modeling more effective to a facial skin color for extracting a facial area. 1 used efficient HOLA(Higher order local autocorrelation function) using 26 feature vectors to obtain both feature vectors of a facial area and the edge image extraction using Harr wavelet in image which split a facial area. Calculated feature vectors are used of date for the facial recognition through learning of neural network It demonstrate improvement in both the recognition rate and speed by proposed algorithm through simulation.