• Title/Summary/Keyword: spectral study

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Speech enhancement using psychoacoustics model (사이코어쿠스틱스 모델을 이용한 음성 향상)

  • Kwon, Chul-Hyun;Shin, Dae-Kyu;Park, Sang-Hui
    • Proceedings of the KIEE Conference
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    • 1999.11c
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    • pp.748-750
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    • 1999
  • In this study, a speech enhancement is presented based on the utilization of well-known auditory mechanism, noise masking. The speech enhancement approach adopted here is to derive an modifier that achieves audible noise suppression. This modification selectively affects the perceptually significant spectral values, and is therefore less prone to introduction of unwanted distortions than methods that affect the complete STSA and produces more enhanced results at low SNR as well as at high SNR. The speech enhancement method adopted here needs exact estimation of the minimum specteal value per critical band because it uses only the minimum spectral value per critical band. For this, the method adopted here uses the modified spectral subtraction that is more flexible than power spectral subtraction. So, the result in experiment represented better SNR than before.

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Spectral Reflectance Characteristics and Vegetation Indices for Field Crops (밭작물의 분광반사특성과 식생지수)

  • Park, Jong-Hwa;Shin, Yong-Hee;Park, Min-Seo
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2003.10a
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    • pp.627-630
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    • 2003
  • This research determined the spectral reflectance characteristics and vegetation indices when intermixed with field crops and soil. Ground-level spectral reflectance were collected in the field experiment containing plots of soybean and other seven crops. The first and second derivative of reflectance spectra showed several peaks that were dependent in different degrees on leaf age and chlorophyll concentration in the crop leaves. This study evaluated a number of spectral indices for estimating chlorophyll concentrations at the leaf scale difference, using samples from field crops at various stages of senescence. Five vegetation indices were evaluated which had advantages over previous techniques. Experimental data recorded on field crops during the growing season are in good agreement with previous theoretical results.

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Study on the physical mechanism of nonlinear gain in semiconductor lasers (반도체 레이저의 비선형 이득의 물리적인 매카니즘에 관한 연구)

  • 김창봉;엄진섭
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.9
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    • pp.72-79
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    • 1997
  • The dominant physical process repsonsible for the nonlinear gain is from spectral-hole burning with the time constant fo about 50fs and the contribution to the nonlinea rgain form hot carriers effect is determined to be about 15% of the contribution due to spectral-hole burning. To prove the above results we fit the data of hall and found that hot carriers have a profound effect on their experimental data despite the fact that the magnitude of hot carriers effect is only 15% of spectral-hole burning. We suggest that the experimenta with a pump pulse width of 180 fs is very sensitive in detecting the effect of hot carriers, but is not sensitive in detecting much faster process associated with spectral-hole burning.

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A STUDY ON SPATIAL FEATURE EXTRACTION IN THE CLASSIFICATION OF HIGH RESOLUTIION SATELLITE IMAGERY

  • Han, You-Kyung;Kim, Hye-Jin;Choi, Jae-Wan;Kim, Yong-Il
    • Proceedings of the KSRS Conference
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    • 2008.10a
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    • pp.361-364
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    • 2008
  • It is well known that combining spatial and spectral information can improve land use classification from satellite imagery. High spatial resolution classification has a limitation when only using the spectral information due to the complex spatial arrangement of features and spectral heterogeneity within each class. Therefore, extracting the spatial information is one of the most important steps in high resolution satellite image classification. In this paper, we propose a new spatial feature extraction method. The extracted features are integrated with spectral bands to improve overall classification accuracy. The classification is achieved by applying a Support Vector Machines classifier. In order to evaluate the proposed feature extraction method, we applied our approach to KOMPSAT-2 data and compared the result with the other methods.

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Adjusted Direct Orthogonal Signal Correction For High-Dimensional Spectral Data (고차원 스펙트라 데이터 분석을 위한 Adjusted Direct Orthogonal Signal Correction 기법)

  • Kim, Sin-Young;Kim, Seoung-Bum
    • Journal of Korean Institute of Industrial Engineers
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    • v.37 no.4
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    • pp.400-407
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    • 2011
  • Modeling and analysis of high-dimensional spectral data provide an opportunity to uncover inherent patterns in various information-rich data. Orthogonal signal correction (OSC) a preprocessing technique has been widely used to remove unwanted variations of spectral data that do not contribute to prediction or classification. In the present study we propose a novel OSC algorithm called adjusted direct OSC to improve visualization and the ability of classification. Experimental results with real mass spectral data from condom lubricants demonstrate the effectiveness of the proposed approach.

Vowel Formant Trajectory Patterns for Shared Vowels of American English and Korean

  • Chung, Hyun-Ju;Kong, Eun-Jong;Weismer, Gary
    • Phonetics and Speech Sciences
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    • v.2 no.4
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    • pp.67-74
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    • 2010
  • The purpose of this study was to explore the cross-linguistic difference in the spectral movement pattern of American English and Korean vowels. Eight American vowels /a/, /e/, /$\varepsilon$/, /i/, /I/, /o/, /u/, and /$\mho$/, and five Korean vowels, /a/, /e/, /i/, /o/ and /u/ in a fricative-vowel environment produced by adult speakers of each language were analyzed. The spectral movement patterns of the first two formant frequency values were measured and analyzed. The results showed that Korean vowels had minimal spectral movement, both in F1 and F2 values, as compared to American English vowels. Moreover, no consistent direction of movement was found in the three corner Korean vowels, while American English vowels showed consistent direction of movement for each vowel of the same phonemic category.

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Energy consumption by Spectral Power Distribution Of LED lighting (LED 조명의 분광 분포에 따른 건물에너지 소비)

  • Jung, Ho-Youn;Kim, Hyo-In;Kim, Gon;Yun, Geun-Young
    • KIEAE Journal
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    • v.12 no.3
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    • pp.101-106
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    • 2012
  • Lighting energy accounts for approximately 20% of the electrical energy used worldwide. Thus, High efficiency Light emitting diode(LED)lighting is getting more popular as the next generation lighting replaced to traditional lighting fixtures. Also, LED lighting not only has a long lifetime but also can realize a variety visual environments through the wavelengh control. The lighting energy varies depending on the Spectral Power Distribution(SPD) even though the Illuminance level is same. Therefore, This study indicates that the difference of indoor energy consumption under the same illuminance level when Spectral Power Distribution(SPD) is different. As a result, Lighting energy consumption under red-color emphasizing SPD is about 10% lower than under blue-color emphasizing SPDs.

A study on the transfromation from CMYK to Labcolor space using color reproduction models (색재현 모델을 이용한 CMYK to Lab 색변환에 관한 연구)

  • 차재영;구철회
    • Proceedings of the Korean Printing Society Conference
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    • 2000.04a
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    • pp.25-34
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    • 2000
  • Recently, color proofing in printing industry grow rapidly. If an order decide color from known color information in the case of color reproduction, we can reduce expenses and time. In color proofing the best important point must be closed proofed color to primary color and secondary color. Model-based approaches have the advantages of faster recharacterization and the opportunity of simulating product enhancements such as changes in ink properties and halftoning. In this paper, we transformed the dot area of CMYK to CIELAB color space using color reprodution models. Firstly, we measured spectral reflectance of primary color printed by Matchprint II and the data was used to find tone reproduction curve using regression equation, and than we applied at primary color model, such as Murray-Davies, Yule-Nilsen, and mixed color model, such as Kubelka--Munk, relaxed version of spectral Neugebauser. In such results, the Kubleka-Munk model resulted in the best spectral reconstruction accuracy followed by relaxed version of spectral Neugebauer model, color difference is 2.8401.

A study on the Transformation from CMYK to $L^{*}a^{*}b^{*}$ color space using color reproduction models (색재현 모델을 이용한 CMYK에서 $L^{*}a^{*}b^{*}$ 색변환에 관한 연구)

  • 차재영;조가람;구철희
    • Journal of the Korean Graphic Arts Communication Society
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    • v.18 no.2
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    • pp.29-40
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    • 2000
  • Recently. color proofing in printing industry grow rapidly. If an order decide color from known color information in the case of color reproduction, we can reduce expenses and time. In color proofing the best important point must be closed proofed color to primary color and secondary color. Model-based approaches have the advantages of faster recharacterization and the opportunity of simulating product enhancements such as changes in ink properties and halftoning. In this paper, we transformed the dot area of CMYK to CIELAB color space using color reproduction models. Firstly, we measured spectral reflectance of primary color printed by Matchprint II and the data was used to find tone reproduction curve using regression equation, and than we applied at primary color model, such as Murray-Davies, Yule-Nilsen, and mixed color model, such as Kubelka-Munk, relaxed version of spectral Neugebauer. In such results, the Kubelka-Munk model resulted in the best spectral reconstruction accuracy followed by relaxed version of spectral Neugebauer model, color difference is 2.8401.

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The Endmember Analysis for Sub-Pixel Detection Using the Hyperspectral Image

  • Kim, Dae-Sung;Cho, Young-Wook;Han, Dong-Yeob;Kim, Young-Il
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.732-734
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    • 2003
  • In the middle -resolution remote sensing, the Ground Sampled Distance(GSD) sensed and sampled by the detector is generally larger than the size of objects(or materials) of interest, in which case several objects are embedded in a single pixel and cannot be detected spatially. This study is intended to solve this problem of a hyperspectral data with high spectral resolution. We examined the detection algorithm, Linear Spectral Mixing Model, and also made a test on the Hyperion data. To find class Endmembers, we applied two methods, Spectral Library and Geometric Model, and compared them with each other.

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