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웨이블릿 변환을 이용한 디지털 워터마킹 방법에 관한 연구
전형섭,현기호 영산대학교 2002 영산논총 Vol.9 No.-
The rapid expansion of the Internet in the past few years has rapidly increased the availability of digital data such as audio, images and videos to the public. Therefore, The need for copyright protect of digital data are increasing in the internet. In this paper, we study several multiresolution watermarking method for digital images. The digital watermarking method is based on the discrete wavelet transform (DWT). The results presented in this paper are quite convincing and truly demonstrate the robustness of wavelet-based watermarking method to fundamental image processing operations.
전형섭,최연웅,조기성 전북대학교 공학연구원 ( 구 전북대학교 공업기술연구소 ) 2003 工學硏究 Vol.34 No.-
On this study, to deal with meteorological satellite data in general data processing system without high cost of meteorological satellite data processing equipment, it studied the geometric correction method which could be coincided with real world coordinate and adjusted the spatial resolution of meteorological satellite data to observe the change of local meteorological environment. As the result of geometric correction, the Root Mean Squared Error(RMSE) generally decreased as the number of control points increased, but the minimum of these was generated in the third and fourth degree formula using 25 control points. As a result of resampling, the RMSE had no connection with the pixel size of it. Therefore when using 25 control points as uniform distribution and the polynomial expression of fourth degree as conversion formula, we could get the most appropriate result for general utilization of GMS imagery.
전형섭,임승현,조기성 전북대학교 공학연구원 ( 구 전북대학교 공업기술연구소 ) 2003 工學硏究 Vol.34 No.-
Recently, landuse and landcover are suddenly changing by the urban development with population concentration, constrruction of the society base equipment and the reclamation project, so using this is became more densified, and the demand, which should be digitalized by society information, is increasing. Therefore, to manage efficiently the country, which is changing hourly, the method, which can detect and change wide landuse and landcover quickly and correctly, is demanding. This study quantitatively tried to detect the course of change, which used the classificated result of the detected satellite imagery with different time, and the source of the change, after the study, it could be gotten these conclusion. First, there was change about 33.19% with different time after presuming landcover change using the post-classificated change detection method, which is comparison of the classificated result of landcover, and it could be decided the change volume of each class, but it couldn't be known the change course of the landcover. Second, after detecting change of landcover, which used the mixed change detection method presented in this study, there was landcover change about 24.29% and it could indicate the change volume in addition to the change course of each landcover class, so it was made the basis, which could organically be the landcover management and environmental management. Third, while in the normal method the countered change volume of landcover presents the offset result, it could detect the offset volume in the mixed chage detection method, so it could indicate that the actual landcover change rate is about 19.82%
RFM을 이용한 고해상도 위성영상의 기하보정에 관한 연구
전형섭,정용주,조기성 전북대학교 공학연구원 ( 구 전북대학교 공업기술연구소 ) 2003 工學硏究 Vol.34 No.-
Manufacturing of the large scale map using the high-resolution satellite data requires high-precision geometric correction, and for this the location ephemeris data as like the location and attitude of the satellite sensor, which is an orbit component model, is needed, but in IKONOS satillite these are not porvided because of the business technology protection. Therefore, in this study, as the basic course for obtaining the ground coordinates from the IKONOS satellite imagery, using the ground control point without the satellite aid data it derived RMF's coefficient in the geometric correction of high-resolution satellite imagery, did the geometric correction using RFM and evaluated accuracy, and then finally it could be gotten the follwing conclusion as the result of evaluating the RMF's usefulness. First, as the result of applying to the least square method, to derive the coefficient of RFM using the ground control point, in the case of using the third order expression, it could derived the exact coefficient value about 0.686 pixel(m) of the root mean square error. Second, as the result of comparing the polynominal expression model and RFM, by using RFM it could improve the root mean square error more than 1.5 pixel. Third, RFM is very sensitive to the Z value information, and it could know that using the polynominal expression is more efficient than RFM is if the Z value infromation is inaccurated.