• Title, Summary, Keyword: Signal to noise ratio (SNR)

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Improvement of Signal-to-Noise Ratio for Speech under Noisy Environment (잡음환경 하에서의 음성의 SNR 개선)

  • Choi, Jae-Seung
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.7
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    • pp.1571-1576
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    • 2013
  • This paper proposes an improvement algorithm of signal-to-noise ratios (SNRs) for speech signals under noisy environments. The proposed algorithm first estimates the SNRs in a low SNR, mid SNR and high SNR areas, in order to improve the SNRs in the speech signal from background noise, such as white noise and car noise. Thereafter, this algorithm subtracts the noise signal from the noisy speech signal at each bands using a spectrum sharpening method. In the experiment, good signal-to-noise ratios (SNR) are obtained for white noise and car noise compared with a conventional spectral subtraction method. From the experiment results, the maximal improvement in the output SNR results was approximately 4.2 dB and 3.7 dB better for white noise and car noise compared with the results of the spectral subtraction method, in the background noisy environment, respectively.

A Linear Prediction Based Estimation of Signal-to-Noise Ratio in AWGN Channel

  • Kamel, Nidal S.;Jeoti, Varun
    • ETRI Journal
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    • v.29 no.5
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    • pp.607-613
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    • 2007
  • Most signal-to-noise ratio (SNR) estimation techniques in digital communication channels derive the SNR estimates solely from samples of the received signal after the matched filter. They are based on symbol SNR and assume perfect synchronization and intersymbol interference (ISI)-free symbols. In severe channel distortion where ISI is significant, the performance of these estimators badly deteriorates. We propose an SNR estimator which can operate on data samples collected at the front-end of a receiver or at the input to the decision device. This will relax the restrictions over channel distortions and help extend the application of SNR estimators beyond system monitoring. The proposed estimator uses the characteristics of the second order moments of the additive white Gaussian noise digital communication channel and a linear predictor based on the modified-covariance algorithm in estimating the SNR value. The performance of the proposed technique is investigated and compared with other in-service SNR estimators in digital communication channels. The simulated performance is also compared to the Cram$\acute{e}$r-Rao bound as derived at the input of the decision circuit.

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Evaluation and Comparison of Contrast to Noise Ratio and Signal to Noise Ratio According to Change of Reconstruction on Breast PET/CT (Breast PET CT 영상 재구성 변화에 따른 대조도 대 잡음비와 신호 대 잡음비의 비교평가)

  • Lee, Jea-Young;Lee, Eul-Kyu;Kim, Ki-Won;Jeong, Hoi-Woun;Lyu, Kwang-Yeul;Park, Hoon-Hee;Son, Jin-Hyun;Min, Jung-Whan
    • Journal of radiological science and technology
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    • v.40 no.1
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    • pp.79-85
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    • 2017
  • The purpose of this study was to measure contrast to noise ratio (CNR) and signal to noise ratio (SNR) according to change of reconstruction from region of interest (ROI) in breast positron emission tomography-computed tomography (PET-CT), and to analyze the CNR and SNR statically. We examined images of breast PET-CT of 100 patients in a University-affiliated hospital, Seoul, Korea. Each patient's image of breast PET-CT were calculated by using ImageJ. Differences of CNR and SNR among four reconstruction algorithms were tested by SPSS Statistics21 ANOVA test for there was statistical significance (p<0.05). We have analysis socio-demographical variables, CNR and SNR according to reconstruction images, 95% confidence according to CNR and SNR of reconstruction and difference in a mean of CNR and SNR. SNR results, with the quality of distributions in the order of PSF_TOF, Iterative and Iterative-TOF, FBP-TOF. CNR, with the quality of distributions in the order of PSF_TOF, Iterative and Iterative-TOF, FBP-TOF. CNR and SNR of PET-CT reconstruction methods of the breast would be useful to evaluate breast diseases.

Evaluation and Comparison of Signal to Noise Ratio According to Change of Kernel size of Heart Shadow on Chest Image (흉부 영상에서 커넬 크기변화에 따르는 신호대잡음비 비교평가)

  • Lee, Eul-Kyu;Jeong, Hoi-Woun;Min, Jung-Whan
    • Journal of the Korean Society of Radiology
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    • v.11 no.6
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    • pp.443-451
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    • 2017
  • The purpose of this study was to comparison of measure signal to noise ratio (SNR) according to change of kernel size from region of interest (ROI) of heart shadow in chest image. We examined images of chest image of 100 patients in a University-affiliated hospital, Seoul, Korea. Chest images of each patient were calculated by using ImageJ. We have analysis socio-demographical variables, SNR according to images, 95% confidence according to SNR of difference in a mean of SNR. Differences of SNR among change of equalization were tested by SPSS Statistics21 ANOVA test for there was statistical significance 95%(p<0.05). In SNR results, with the quality of distributions in the order of kernel size 9*9 image, kernel size 7*7 image and original chest image, kernel size 3*3 image (p<0.001). In conclusion, this study would be that quantitative evaluation of heart shadow on chest image can be used as an adjunct to the kernel size chest image.

SNR Analyses for MSC and Camera Electronics Design for Its Improvement

  • Kim Young Sun;Kong Jong-Pil;Heo Haeng-Pal;Park Jong-Euk;Paik Hong-Yul
    • Proceedings of the KSRS Conference
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    • pp.444-447
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    • 2004
  • SNR(Signal to Noise Ratio) is one of the most important performance for the electro-optical camera system. This paper shows not only the SNR analyses for the MSC system, which is the payload in the KOMPSAT2 satellite, but also the trials for its improvement in the electronics circuit design. The MSC deals with one panchromatic band and four multi-spectral bands. The SNR analyses are performed based on the MSC design for the each band and assuming that the defined radiance reached directly to the sensor entrance pupil. In the SNR calculation, shot noise, dark current noise, analog electronics noise and ADC quantization noise are considered as noise sources. In these noise sources, especially, the electronics noise depends on the camera electronics design. This paper shows the camera electronics design to increase SNR and its test results as well as the SNR analyses.

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Performance Improvement of Perceptual Filter Using Noise Energy Control (잡음 에너지 제어를 통한 지각 필터 성능 개선)

  • Seo Joung-Kook;Cha Hyung-Tai
    • The Journal of the Acoustical Society of Korea
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    • v.24 no.1
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    • pp.43-51
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    • 2005
  • In this paper, we propose an algorithm that improves a tone quality of a noisy audio signal in order to enhance a Performance of perceptual filter using noise energy control. Most of the algorithms which were proposed by the other researchers usually applied a filter using the noise energy acquired from a silent range. In this case. the improvement rate of tone quality decreases if the noise energy is changed by the magnitude or environment variation in a signal frame. But the Proposed method Provides the means to find a food estimated noise through energy control of the estimated noise which is obtained from a silent range. Also we can get the enhancement of tone qualify in low frequency band unlike other methods. To show the performance of the Proposed algorithm, various input signals which had a different signal-to-noise ratio (SNR) such as 5dB, l0dB, 15dB and 20dB were used to test the proposed algorithm. With the proposed algorithm, we could confirm the enhancement of tone quality in terms of segmental SNR (SSNR). noise-to-mask ration (NMR) and mean opinion score (MOS) test.

Compensation for the decrease of output SNR of hadamard transform spectrometer with nonideal mask (비이상적 마스크로 인한 하다마드변환 스펙트럼 검파기 출력값의 신호대 잡음비 감소의 해결방안)

  • 남지탁;박진배;윤태성
    • 제어로봇시스템학회:학술대회논문집
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    • pp.4-7
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    • 1997
  • When we use Hadamard transform spectrometers (HTS), we can increase signal to noise ratio(SNR) by multiplexing which is done by masks. But if the mask has a single defective element, output-SNR decreases. In this paper the effect of a single defective element on the output-SNR is investigated. And a method of compensating for the defective mask element is presented.

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Perception of sentences varying with prosody pattern, sound intensity, and signal-to-noise ratio (운율 패턴, 강도, 신호대소음비에 따른 문장 지각 변화)

  • Chang, Son-A;Jang, Eunjoo;Jang, Jaejin
    • Phonetics and Speech Sciences
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    • v.9 no.2
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    • pp.119-124
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    • 2017
  • This study investigates how perception of easy sentences varies with prosody pattern, sound intensity, and signal-to-noise ratio(SNR) in young adults with normal hearing who were in their 20's. The results showed that the presence of proper prosody pattern in the sentences increased correct perception rate of the target sentences, and that the lower the intensity and SNR, the lower the sentence perception scores. The results also showed that SNR had a greater effect on the sentence perception scores than sound intensity. There was a significant decrease of perception scores starting at the level of 15 dB and +3 SNR for the sentences with prosody pattern, while starting at the level of 18 dB and +6 SNR for the sentences without prosody pattern, ending up with a very poor perception score as sound intensity and SNR gets lower. There was a significant difference in the perception score of the sentences with prosody pattern between 20 year-old group and 21 year or older group in several listening conditions of sound intensity and SNR.

An Improved Spin Echo Train De-noising Algorithm in NMRL

  • Liu, Feng;Ma, Shuangbao
    • Journal of Information Processing Systems
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    • v.14 no.4
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    • pp.941-947
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    • 2018
  • Since the amplitudes of spin echo train in nuclear magnetic resonance logging (NMRL) are small and the signal to noise ratio (SNR) is also very low, this paper puts forward an improved de-noising algorithm based on wavelet transformation. The steps of this improved algorithm are designed and realized based on the characteristics of spin echo train in NMRL. To test this improved de-noising algorithm, a 32 points forward model of big porosity is build, the signal of spin echo sequence with adjustable SNR are generated by this forward model in an experiment, then the median filtering, wavelet hard threshold de-noising, wavelet soft threshold de-noising and the improved de-noising algorithm are compared to de-noising these signals, the filtering effects of these four algorithms are analyzed while the SNR and the root mean square error (RMSE) are also calculated out. The results of this experiment show that the improved de-noising algorithm can improve SNR from 10 to 27.57, which is very useful to enhance signal and de-nosing noise for spin echo train in NMRL.

A Study on Variation and Determination of Gaussian function Using SNR Criteria Function for Robust Speech Recognition (잡음에 강한 음성 인식에서 SNR 기준 함수를 사용한 가우시안 함수 변형 및 결정에 관한 연구)

  • 전선도;강철호
    • The Journal of the Acoustical Society of Korea
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    • v.18 no.7
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    • pp.112-117
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    • 1999
  • In case of spectral subtraction for noise robust speech recognition system, this method often makes loss of speech signal. In this study, we propose a method that variation and determination of Gaussian function at semi-continuous HMM(Hidden Markov Model) is made on the basis of SNR criteria function, in which SNR means signal to noise ratio between estimation noise and subtracted signal per frame. For proving effectiveness of this method, we show the estimation error to be related with the magnitude of estimated noise through signal waveform. For this reason, Gaussian function is varied and determined by SNR. When we test recognition rate by computer simulation under the noise environment of driving car over the speed of 80㎞/h, the proposed Gaussian decision method by SNR turns out to get more improved recognition rate compared with the frequency subtracted and non-subtracted cases.

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