• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.237-240
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• 2004

In this study, the digital image processing with image enhancement based on homomorphic filtering was performed using geophysical imaging data such as gravity, magnetic data and sub-scenes of satellite images such as LANDSAT, IKONOS, and KOMPSAT. Windows application program for executing homomorphic filtering was designed and newly implemented. In general, homomorphic filtering is technique that is based on Fourier transform, which enhances the contrast of image by removing the low frequencies and amplifying the high frequencies in frequency domain. We can enhance the image selectively using homomorphic filtering as compared with the existing method, which enhance the image totally. Through several experiment using remotely sensed imagery and geophysical image with this program, it is concluded that homomorphic filtering is more effective to reveal distinct characteristics for some complicated and multi-associated features on image data.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1332-1333
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• 2003

• 한국지구과학회지
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• 제26권1호
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• pp.58-65
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• 2005

호모몰픽 필터링은 푸리에 변환에 기초를 둔 기법으로 주파수 영역에서 저주파 신호는 약화시키고 고주파 신호는 강화하여 영상의 대비 차를 강화시키는 처리기법이다. 호모몰픽 필터링을 위한 응용 프로그램을 개발하여 인공위성영상과 지구물리 자력탐사 자료를 이미지화한 영상에 시험적으로 적용하여 그 결과를 분석하였다. 영상평활화 기법이나 커널 마스크 처리 등과 같은 영상강화 기법에서는 추출 가능한 경계부의 위치를 변화시키거나 영상의 화소값이 전체 영상을 대상으로 변화시키는 반면에 호모몰픽 필터링은 세부적인 영상 정보의 내용을 선택적으로 강조할 수 있다. 호모몰픽 필터링은 인공위성 영상에서 복잡한 지형지물의 특성을 추출하거나 분리하는 데 효과적인 방법으로 나타났으며 지구물리 영상자료에서 이상대를 조사하는 경우에도 유용하게 적용될 수 있을 것으로 생각된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.376-383
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• 2005

In this study, we conducted geophysical investigations for the organization of integrated geophysical methods to detect underground cavities of ground subsidence area at the field test site, located at Yongweol-ri, Muan-gun. We examined the applicability of geophysical methods such as electrical resistivity, electromagnetic, and microgravity to cavity detection with the aid of borehole survey results. Underground cavities are widely present within the limestone bedrock overlain by the alluvial deposits in the area of the test site where the ground subsidences have occurred in the past. The limestone cavities are mostly filled with groundwater and clays in the test site. Thus, cavities have low electrical resistivity and density compared to the surrounding host bedrock. The results of the study have shown that the zones of low resistivity and density correspond to the zones of the cavities identified in the boreholes at the site, and that the geophysical methods used are very effective to detect underground cavities. Furthermore, we could map the distribution of cavities more precisely with the test results incorporated from the various geophysical methods. It is also important to notice that the microgravity method is a very promising tool since it has rarely used for the cavity detection in korea. Beyond the investigation of underground cavities, the geophysical methods are required to provide useful information for the reinforcement design for the ground subsidence areas. It is, therefore, necessary to develop integrated geophysical technique incorporating different geophysical methods to precisely map underground cavities and image the subsurface of the ground subsidence areas.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1264-1267
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• 2003

To protect the digital image, video and audio from non-authorized use, the digital watermarking technology has received a great attention in the field of multimedia in recent years . An overview of the development of watermark techniques is given in the current paper followed by a discussion of potential application of spatial domain, transform domain watermark techniques in remote sensing images copyright protection and verification in different forms of processed images.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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• pp.54-57
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• 2007

Recently, multidimensional joint inversion of geophysical data based on fundamentally different physical properties has been actively studied. Joint inversion can provide a way to much more accurately image the subsurface structure. Through the joint inversion, furthermore, it is possible to directly estimate non-geophysical material properties from geophysical measurements. In this study, I derive the objective functions and normal equations of three different joint inversion approaches: one approach based on the structural similarity using cross-gradient, and the other two using the a priori information on the model parameters and the correlation between material properties. Since all the equations derived in this study are based on the same inversion method (smoothness constrained least-squares), it is possible to mix the joint inversion methods so as to produce a new joint inversion algorithm.

• 지구물리
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• 제4권3호
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• pp.183-195
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• 2001

This paper contains and facts to a number of projects on "content-based access to image databases" around the world today. The main focus is on what kind of image features are used but also the user interface and the users possibility to interact with the system.

• 지구물리와물리탐사
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• 제3권1호
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• pp.25-32
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• 2000

최근 토목, 지하수탐사, 환경분야 등에서 각종 지구물리탐사자료의 수요 증가와 이들 자료의 품질관리 및 전산화에 대한 필요성이 대두되고 있다. 따라서, 지구물리 탐사자료의 효율적 관리 및 공유를 위하여 Client/Server(C/S)환경 및 웹(Web)환경 물리탐사자료 관리시스템을 개발하였다. C/S환경의 관리시스템은 MS SQL-Server을 이용하여 관계형 데이터베이스 시스템으로 설계하였고 각종 물리탐사 자료의 규격화, Window용 C/S 인터페이스 프로그램 개발, 검색자료 전송 프로그램 개발 등으로 특징된다. 웹환경에서의 일반 사용자용 데이터베이스 시스템은 물리탐사 이미지자료 표현을 위한 플러그인 모듈개발과, 한국자원연구소 웹사이트 개설 및 홈페이지 작성 등으로 이루어진다.

• 지구물리와물리탐사
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• 제2권2호
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• pp.112-121
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• 1999

This article reviews the development of geophysical inverse theory. In a series of articles published in 1967, 1968, and 1979, G. Backus and F. Gilbert a trade-off between model resolution and estimation errors in geophysical inverse problems, and gave a criterion to compromise the reciprocal relation. Although the criterion was not clear in the physical point of view, it had been extensively used in the interpretation of geophysical date in the 1970s. This was the starting point of the fruitful development of inverse theory in geophysics. A reasonable criterion to compromise the reciprocal relation was derived to solve linear problems by D. D. jackson in 1979, introducing the concept of a priori information about unknown model parameters. This Jackson's approach was extended to solve nonlinear problems on the basis o probabilistic approach to the inverse problems formulated by A. Tarantola and B. Vallete in 1982. At the end of 1980s ABIC (Akaike Bayesian Information Criterion) was introduced for selecting a more reasonable model in geophysics. Now the date inversion is regarded as the process of extracting new information from observed data, combining in with a priori information about model parameters, and constructing a more clear image of model.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권2호
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• pp.1-23
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• 2022

For its essential importance as a resource, sustainable development of groundwater has been major research interests for many decades. Conventional characterization of aquifer and groundwater has relied on borehole data from observation well. Although borehole data provide useful information on yield and flow of groundwater, it is often difficult and sometimes costly to estimate the spatial distribution of groundwater in entire aquifer. Geophysical probing is an alternative techique that provides such information due to its capability to image subsurface structures as well as to delineate spatial distribution of hydraulic parameters. This study presents various technical information about geophysical probing to estimate main characteristics of aquifer for groundwater exploitation. Subsequently, we analyzed representative cases, in which geophysical methods were applied to identify the location of the groundwater, classify freshwater and brine, derive hydraulic constants, and monitor groundwater.