• Title/Summary/Keyword: Noise Removing

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ST-Segment Analysis of ECG Using Polynomial Approximation (다항식 근사를 이용한 심전도의 ST-Segment 분석)

  • Jeong, Gu-Young;Yu, Kee-Ho;Kwon, Tae-Kyu;Lee, Seong-Cheol
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.8
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    • pp.691-697
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    • 2002
  • Myocardial ischemia is a disorder of cardiac function caused by insuficient blood flow to the muscle tissue of the heart. We can diagnose myocardial ischemia by observing the change of ST-segment, but this change is temporary. Our primary purpose is to detect the temporary change of the 57-segment automatically In the signal processing, the wavelet transform decomposes the ECG(electrocardiogram) signal into high and low frequency components using wavelet function. Recomposing the high frequency bands including QRS complex, we can detect QRS complex more easily. Amplitude comparison method is adopted to detect QRS complex. Reducing the effect of noise to the minimum, we grouped ECG by 5 data and compared the amplitude of maximum value. To recognize the ECG .signal pattern, we adopted the polynomial approximation partially and statistical method. The polynomial approximation makes possible to compare some ECG signal with different frequency and sampling period. The ECG signal is divided into small parts based on QRS complex, and then, each part is approximated to the polynomials. After removing the distorted ECG by calculating the difference between the orignal ECG and the approximated ECG for polynomial, we compared the approximated ECG pattern with the database, and we detected and classified abnormality of ECG.

Real-Time Digital Auto-Focusing Using A-Priori Estimated Point Spread Functions (점 확산 함수 데이터베이스를 이용한 실시간 디지털 자동초점)

  • Yoo Yoon-Jong;Lee Jung-Soo;Shin Jeong-Ho;Paik Joon-Ki
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.43 no.5 s.311
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    • pp.1-11
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    • 2006
  • This paper presents a digital auto-focusing method using a priori estimated point-spread-functions (PSF) database. The proposed algorithm efficiently removes out-of-focus blur in a degraded input image by selecting the optimal PSF from the database. The database consists of optical characteristics of image formation system. The PSF selection Process is performed based on a novel focusing measure. The proposed method includes a spatially adaptive filter for removing both noise and ringing artifacts. Experimental results show that the proposed method efficiently removes out-of-focus blur using significantly reduced computational load compared with the existing method.

A Study on the Intelligent 3D Foot Scanning System (인공지능형 삼차원 Foot Scanning 시스템에 관한 연구)

  • Kim, Young-Tak;Park, Ju-Won;Tack, Han-Ho;Lee, Sang-Bae
    • Journal of the Korean Institute of Intelligent Systems
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    • v.14 no.7
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    • pp.871-877
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    • 2004
  • In this paper, for manufacturing a custom-made shoes, shape of foot acquired three-dimensional measurement device which makes shoe-last data for needing a custom-made shoes is founded on artificial intelligence technique and it shows method restoring to the original shape in optimized state. the developed system for this study is based on PC which uses existing three dimensional measurement method. And it gains shoe-last and data of foot shape going through 8 CCD(Charge Coupled Device) Which equipped top and bottom, right and left sides and 4 lasers which also equipped both sides and upper and lower sides. The acquired data are processed image processing algorithm using artificial intelligence technique. And result of data management is better quality of removing noise than other system not using artificial intelligence technique and it can simplify post-processing. So, this paper is constituted hardware and software system and it used neural network for determining threshold value, when input image on pre-processing step is being stage of image binarization and present that results.

Segmentation and 3-Dimensional Reconstruction of Liver using MeVisLab (MeVisLab을 이용한 간 영역 분할 및 3차원 재구성)

  • Shin, Min-Jun;Kim, Do-Yeon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.8
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    • pp.1765-1772
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    • 2012
  • Success rate of transplantation of body organs improved due to development of medical equipment and diagnostic technology. In particular, a liver transplant due to liver dysfunction has increased. With the development of image processing and analysis to obtain the volume for liver transplantation have increased the accuracy and efficiency. In this thesis, we try to reconstruct the regions of the liver within three dimensional images using the mevislab tool, which is effective in quick comparison and analysis of various algorithms, and in expedient development of prototypes. Liver is divided by applying threshold values and region growing method to the original image, and by removing noise and unnecessary entities through morphology and region filling, and setting of areas of interest. It is deemed that high temporal efficiency, and presentation of diverse range of comparison and analysis module application methods through usage of MeVisLab would make contribution towards expanding of baseline of medical image processing researches.

Detection of Yellow Sand Dust over Northeast Asia using Background Brightness Temperature Difference of Infrared Channels from MODIS (MODIS 적외채널 배경 밝기온도차를 이용한 동북아시아 황사 탐지)

  • Park, Jusun;Kim, Jae Hwan;Hong, Sung Jae
    • Atmosphere
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    • v.22 no.2
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    • pp.137-147
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    • 2012
  • The technique of Brightness Temperature Difference (BTD) between 11 and $12{\mu}m$ separates yellow sand dust from clouds according to the difference in absorptive characteristics between the channels. However, this method causes consistent false alarms in many cases, especially over the desert. In order to reduce these false alarms, we should eliminate the background noise originated from surface. We adopted the Background BTD (BBTD), which stands for surface characteristics on clear sky condition without any dust or cloud. We took an average of brightness temperatures of 11 and $12{\mu}m$ channels during the previous 15 days from a target date and then calculated BTD of averaged ones to obtain decontaminated pixels from dust. After defining the BBTD, we subtracted this index from BTD for the Yellow Sand Index (YSI). In the previous study, this method was already verified using the geostationary satellite, MTSAT. In this study, we applied this to the polar orbiting satellite, MODIS, to detect yellow sand dust over Northeast Asia. Products of yellow sand dust from OMI and MTSAT were used to verify MODIS YSI. The coefficient of determination between MODIS YSI and MTSAT YSI was 0.61, and MODIS YSI and OMI AI was also 0.61. As a result of comparing two products, significantly enhanced signals of dust aerosols were detected by removing the false alarms over the desert. Furthermore, the discontinuity between land and ocean on BTD was removed. This was even effective on the case of fall. This study illustrates that the proposed algorithm can provide the reliable distribution of dust aerosols over the desert even at night.

Interference Cancellation On-Channel Regenerative Repeater for the Single Frequency Network of ATSC Terrestrial Broadcasting (ATSC 지상파 방송의 단일주파수 망 구성을 위한 간섭제거 동일 채널 재생 중계기)

  • Kim, Yong-Seok;Ki, Jang-Geun;Lee, Kyu-Tae
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.11 no.6
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    • pp.295-302
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    • 2011
  • In this paper we consider technological requirements to broadcast digital television signals using single frequency networks(SFN) in the Advanced Television Systems Committee(ATSC) transmission systems and propose Interference Cancellation Digital On Channel Regenerative Repeater(IC-DOCR) thar overcomes the limitation of EDOCR(Equalization Digital On Channel Repeater) proposed by ETRI. The proposed IC-DOCR maintains the benefits of EDOCR that have good output signal quality removing multi-path, additive white Gaussian noise(AWGN). In additional, since the Interference Cancellation algorithm using the 8-VSB symbol demodulation of received signal removes the Interference of feedback signal, IC-DOCR improve the weakness of EDOCR that have low isolation between receive and transmit antenna so that can overcome the limitation of output signal power. we did analysis and verification of the proposed system performance using computational simulation.

Facial Image Recognition Based on Wavelet Transform and Neural Networks (웨이브렛 변환과 신경망 기반 얼굴 인식)

  • 임춘환;이상훈;편석범
    • Journal of the Institute of Electronics Engineers of Korea TE
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    • v.37 no.3
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    • pp.104-113
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    • 2000
  • In this study, we propose facial image recognition based on wavelet transform and neural network. This algorithm is proposed by following processes. First, two gray level images is captured in constant illumination and, after removing input image noise using a gaussian filter, differential image is obtained between background and face input image, and this image has a process of erosion and dilation. Second, a mask is made from dilation image and background and facial image is divided by projecting the mask into face input image Then, characteristic area of square shape that consists of eyes, a nose, a mouth, eyebrows and cheeks is detected by searching the edge of divided face image. Finally, after characteristic vectors are extracted from performing discrete wavelet transform(DWT) of this characteristic area and is normalized, normalized vectors become neural network input vectors. And recognition processing is performed based on neural network learning. Simulation results show recognition rate of 100 % about learned image and 92% about unlearned image.

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6-Gbps Single-ended Receiver with Continuous-time Linear Equalizer and Self-reference Generator (기준 전압 발생기와 연속 시간 선형 등화기를 가진 6 Gbps 단일 종단 수신기)

  • Lee, Pil-Ho;Jang, Young-Chan
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.9
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    • pp.54-61
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    • 2016
  • A 6-Gbps single-ended receiver with a linear equalizer and a self-reference generator is proposed for a high-speed interface with the double data rate. The proposed single-ended receiver uses a common gate amplifier to increase a voltage gain for an input signal with low voltage level. The continuous-time linear equalizer which reduces gain to the low frequencies and achieves high-frequency peaking gain is implemented in the common gate amplifier. Furthermore, a self-reference generator, which is controlled with the resolution 2.1 mV using digital averaging method, is implemented to maximize the voltage margin by removing the offset noise of the common gate amplifier. The proposed single-ended receiver is designed using a 65-nm CMOS process with 1.2-V supply and consumes the power of 15 mW at the data rate of 6 Gbps. The peaking gain in the frequency of 3 GHz of the designed equalizer is more than 5 dB compared to that in the low frequency.

Extraction of Lumbar Multifidus Muscle using Ultrasound Imaging (초음파 영상에서 다열근 추출)

  • Kim, Kwang-Baek;Shin, Sang-Ho
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.2
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    • pp.55-60
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    • 2011
  • In this paper, we propose a new method for extracting muscles from lumbar images. The proposed method sets areas without distortions with field expert's assistance as areas of measuring interest and removing noises from initial ultrasonic videos. Then, the method emphasizes the brightness contrast with Ends-in search stretching algorithm and separate thoracic vertebra from subcutaneous fat area using morphological characteristics. 4-directions contour tracing algorithm is applied to extract the bottom of subcutaneous fat area. Extracting thoracic vertebra area requires noise removal and morphological characteristics as well among candidate areas obtained by controlling min-max brightness. The thickness of muscles is then defined as the length between subcutaneous fat area and extracted thoracic vertebra. The experiment which consists of 368 image analysis verifies that the proposed method is more effective in measuring the thickness of muscles than before.

Ground-Motion Prediction Equations based on refined data for dynamic time-history analysis

  • Moghaddam, Salar Arian;Ghafory-Ashtiany, Mohsen;Soghrat, Mohammadreza
    • Earthquakes and Structures
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    • v.11 no.5
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    • pp.779-807
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    • 2016
  • Ground Motion Prediction Equations (GMPEs) are essential tools in seismic hazard analysis. With the introduction of probabilistic approaches for the estimation of seismic response of structures, also known as, performance based earthquake engineering framework; new tasks are defined for response spectrum such as the reference criterion for effective structure-specific selection of ground motions for nonlinear time history analysis. One of the recent efforts to introduce a high quality databank of ground motions besides the corresponding selection scheme based on the broadband spectral consistency is the development of SIMBAD (Selected Input Motions for displacement-Based Assessment and Design), which is designed to improve the reliability of spectral values at all natural periods by removing noise with modern proposed approaches. In this paper, a new global GMPE is proposed by using selected ground motions from SIMBAD to improve the reliability of computed spectral shape indicators. To determine regression coefficients, 204 pairs of horizontal components from 35 earthquakes with magnitude ranging from Mw 5 to Mw 7.1 and epicentral distances lower than 40 km selected from SIMBAD are used. The proposed equation is compared with similar models both qualitatively and quantitatively. After the verification of model by several goodness-of-fit measures, the epsilon values as the spectral shape indicator are computed and the validity of available prediction equations for correlation of the pairs of epsilon values is examined. General consistency between predictions by new model and others, especially, in short periods is confirmed, while, at longer periods, there are meaningful differences between normalized residuals and correlation coefficients between pairs of them estimated by new model and those are computed by other empirical equations. A simple collapse assessment example indicate possible improvement in the correlation between collapse capacity and spectral shape indicators (${\varepsilon}$) up to 20% by selection of a more applicable GMPE for calculation of ${\varepsilon}$.