• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.3
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• pp.120-131
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• 2020

Water body detection using remote sensing based on machine interpretation of satellite image is efficient for managing water resource, drought and flood monitoring. In this study, water body detection with SAR satellite image based on machine learning was performed. However, non water body area can be misclassified to water body because of shadow effect or objects that have similar scattering characteristic comparing to water body, such as roads. To decrease misclassifying, 8 combination of morphology open filtered band, DEM band, curvature band and Cosmo-SkyMed SAR satellite image band about Mokpo region were trained to semantic segmentation machine learning models, respectively. For 8 case of machine learning models, global accuracy that is final test result was computed. Furthermore, concordance rate between landcover data of Mokpo region was calculated. In conclusion, combination of SAR satellite image, morphology open filtered band, DEM band and curvature band showed best result in global accuracy and concordance rate with landcover data. In that case, global accuracy was 95.07% and concordance rate with landcover data was 89.93%.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.4
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• pp.363-370
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• 2017

In this paper, we proposed a low-complexity speech enhancement algorithm based on a improved minima controlled recursive averaging (IMCRA) and log minimum mean square error (logMMSE). The IMCRA algorithm track the minima value of input power within buffers in local window and identify the speech presence using ratio between input power and its minima value. In this process, many number of operations are required. To reduce the number of operations of IMCRA algorithm, minima value is tracked using time-varying frequency-dependent smoothing based on speech presence probability. The proposed algorithm enhanced speech quality by 2.778%, 3.481%, 2.980% and 2.162% in 0, 5, 10 and 15dB SNR respectively and reduced computational complexity by average 9.570%.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.1
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• pp.155-163
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• 2010

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on-board the NASA's Terra spacecraft provides along-track digital stereo image data at 15m resolution with a base-height ratio 0.6. Automated stereocorrelation procedure was implemented using the ENVI 4.1 software to derive DEMs with $15m{\times}15m$ in 43km long and 50km wide area using the ASTER stereo images. The accuracy of DEMs was analyzed in comparison with those which were obtained from digital topographic maps of 1:25,000 scale. Results indicate that RMSE in elevation between ${\pm}7$ and ${\pm}20m$ could be achieved. Excluding cloud, water and building areas as the factors which make RMSE value exceeding 10m, the accuracy of DEMs showed RMSE of ${\pm}5.789m$. Therefore for the purpose of elevating accuracy of topographic information, we intended to detect the cloud areas and shadow areas by a landcover classification method, remove those areas on the ASTER DEM and then replace with those areas detached from the cartographic DEM by band math.

• Journal of The Geomorphological Association of Korea
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• v.21 no.4
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• pp.121-131
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• 2014

This study analyzed the spectral reflectance characteristics of kaolinite and ASTER(Advanced Spaceborne Thermal Emission and Reflectance Radiometer) image to extract the distribution of kaolin mines in Hadong area, Gyeongsangnam-do. The band ratio model was applied to extract kaolinite using difference of wavelength absorption band distinct feature of minerals from ASTER image which is the major mineral of kaolin mines. According to the spectral reflectance curve of kaolinite, it showed the absorption features around 0.96 and $2.18{\mu}m$ by Al-OH. Also, it affected 1.24 and $1.38{\sim}1.41{\mu}m$ by OH. Applying for new band ratio model from the spectral features of kaolinite to ASTER image, it is possible to make the distribution map of mining traces including present- developing kaolin mines.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.11 no.1
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• pp.55-60
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• 1993

Forest occupied a part of natural ecosystem carries out a role of purifying air, preserving water resource, prevention of the breeding and extermination, recreation areas and etc that preserve and for me one's living environment. In this study, the classification for management of this forest is performed with Landsat TM Image. The classes are decided needle-leaf trees, broad-leaf trees, farming land and grass land, and water. When the TM digital images are classified on computer, water is represented in 7∼13 D.N. of 4th band. But the others is appeared similar mostly specific values so that must be done image processing. When the images compounded 2ed band and 3ed band are processed with ratio of enhancement. Needle-leaf treas is represented in l18∼136 D.N. of 1st band, broad-leaf trees in 72∼91 D.N. of 3ed band, farm land and glass land in 96∼120 of 3ed band. Forest Information is classified with M.L.C, an image classification method. The errors of needle-leaf trees, broad-leaf trees, farm land and grass land, and water are appeared each －7.43, ＋1.89,＋7.58 and －2.04 as compared the digital image with investigation on the scene. Finally, these results are useful for classification of forest vegetation with Landsat TM Image.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6C
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• pp.637-644
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• 2006

This paper presents performance and implementation comparisons of standard and fast DCT algorithms that are commonly used for subband filter bank in MPEG audio coders. The comparison is made according to the architectural difference of the implementation hardware. Fast DCT algorithms are known to have much less computational complexity than the standard method that involves computing a vector dot product of cosine coefficient. But, due to structural irregularity, fast DCT algorithms require extra cycles to generate the addresses for operands and to realign interim data. When algorithms are implemented using DSP processors that provide special operations such as single-cycle MAC (multiply-accumulate), zero-overhead nested loop, the standard algorithm is more advantageous than the fast algorithms. Also, in case of the finite-precision processing, the error performance of the standard method is far superior to that of the fast algorithms. In this paper, truncation errors and algorithmic suitability are analyzed and implementation results are provided to support the analysis.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.1
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• pp.104-110
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• 2009

In this paper, we suggest a new technique which employ the pipelined architecture for the implementation of the SAP adaptive filter using variable step size. According as SAP adaptive filter is sufficiently decomposed, a simplified SAP adaptive filter can be derived, and the weights of adaptive sub-filters can be updated by a simple formular without a matrix inversion. The convergence speed and the steady state error of the simplified SAP adaptive filter are improved by using variable step size. For practical implementation, the simplified SAP adaptive sub-filters are transformed by the pipeline technique.

• The Journal of the Acoustical Society of Korea
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• v.14 no.6
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• pp.32-39
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• 1995

This paper describes a method of musical frequency estimation using tree structured octave band filter banks and the constant Q spectral transform. The performances of the proposed method are compared with those of the conventional constant Q transform using FFT. The performances are evaluated by the estimated fundamental frequency, varying the bandwidth and the frequency resolutions. The results are as follows. With the same frequency resolution of the conventional constant Q transform using FFT, the proposed method gives the better time resolutions, thus, the limit of the processing bandwidth is removed. And, when the bandwidth and the frequency resolution are set high for more accurate results, the computational complexity of the proposed method is less than that of the conventional one.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.91-96
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• 2008

증강현실(Augmented Reality)을 위한 효과적인 비전 기반 인터페이스 개발은 꾸준히 진행되어 왔으나, 대부분 환경적 제약을 받거나, 특수한 장비 혹은 복잡한 모델을 요구한다. 예를 들어, 마커를 이용하면 구현 상의 편의성과 정확성을 보장하지만, 일반적으로 마커는 환경과 대비되는 모양을 가지기 때문에, 사용자에게 거부감을 줄 수 있으며 무엇보다 복잡한 인터랙션에는 적용되기 힘들다. 한편, 손동작을 이용할 경우, 자연스럽고 다양한 인터랙션을 수행할 수 있지만, 색을 이용한 손동작 인식은 복잡한 환경에서 인식률이 크게 저하되고, 3 차원 모델 기반의 손동작 인식은 많은 연산량을 필요로 한다는 문제점을 가진다. 이로 인해 지금까지 제안된 방법을 증강현실 시스템에 적용하는 데는 한계가 있다. 본 논문에서는 기본적으로 손동작을 이용한 인터페이스를 제안하는데, 손동작 인식을 위한 알고리즘을 효율적으로 개선함으로써, 복잡한 환경에서 적은 연산량으로 자연스러운 인터랙션을 제공하고자 한다. 제안방법은 손목에 컬러 밴드를 착용하고, 색 정보를 이용하여 손을 포함하는 최소 영역을 용이하게 검출함으로써, 손 동작 인식률이 좋아지도록 하였다. 제안된 인터페이스는 손의 자연스러운 움직임을 감지해서 손의 모양과 동작에 따라서 가상의 물체를 자연스럽게 제어할 수 있도록 해 준다. 예를 들어, 손이 지정한 위치에 가상의 물체를 나타내고, 가상의 물체를 잡고 다양한 조작을 하는 등의 제어를 할 수 있다. 다양한 환경에서의 실험 및 사용자 평가를 통해 제안된 인터페이스의 유용성을 검증하였다.

• 한국공간정보시스템학회:학술대회논문집
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• 2005.05a
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• pp.249-253
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• 2005

인공위성 데이터를 이용한 원격탐사 기술과 지형공간정보시스템의 통합에 의한 도시에의 활용은 도시 계획뿐 만 아니라, 환경정비와 유지 관리 측면 등에서 중요한 역할을 하고 있다. 본 연구는 대상지역의 Landsat TM 영상자료를 이용하여 보정과정을 수행하고, GSIS 시스템의 NDVI(Normalized Difference Vegetation Index)식을 이용하여 식생지수를 추출하였다. 산출된 식생지수를 5개 등급으로 분류하여 비 식생지역과 식생이 활발한 지역을 구분하여 분석하였고, 인공위성 데이터의 밴드간 비연산 처리를 실시하여 식물의 건강상태를 나타내는 NDVI를 위성 데이터를 이용하여 추출함으로써, 시가지내의 녹지분포에 대한 시계열적 변화를 분석하였다. 이 결과 도심주변지역에 분포하는 낯은 구릉지에서 점차적으로 도시화가 이루어짐을 알 수 있었고, 전체 면적별 녹지분포가 높은 구릉지 및 산악지역의 3, 4, 5등급지역 면적 비율이 68.9%에서 37.2%로 감소한 것으로 나타났다.