• 한국측량학회지
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• 제40권4호
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• pp.275-292
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• 2022

기후변화 감시에 위성 자료 활용을 위해 GCOS (Global Climate Observing System)는 시공간 해상도, 시간 변화에 따른 안정성, 불확실도 등의 요구사항을 제시하고 있다. 천리안위성 2A호의 경우, 센서의 한계로 인해 산출물들이 공간해상도 조건에 충족하지 못하는 경우가 많다. 따라서 본 연구에서는 영상융합 기법들을 천리안위성 2A호 영상에 적용하여 산출물 생성 시 활용될 수 있는 최적의 기법을 찾고자 한다. 이를 위해 CS (Component Substitution), MRA (Multiresolution Analysis), VO (Variational Optimization), DL (Deep Learning)에 포함되는 총 6가지 영상융합 기법을 활용하였다. DL의 경우 합성적(Synthesis) 특성 기반 방법을 훈련자료 구축에 사용하였다. 합성적 특성 기반 방법의 과정은 PAN (Panchromatic)과 MS (Multispectral) 영상의 공간해상도 차이만큼 두 영상의 해상도를 낮춰 융합 영상을 생성한 후 원본 MS 영상과 비교한다. 합성적 특성 기반 방법은 공간해상도를 저하시킨 PAN 영상과 MS 영상 간 기하 특성이 같아야 사용자가 원하는 수준의 융합 영상을 제작할 수 있다. 하지만, 훈련자료 구축 시 비유사성이 존재하기에 이를 최소화하는 방법으로 무작위 비율을 활용한 PSGAN 모델(PSGAN_RD)을 추가로 활용하였다. 융합 영상의 검증은 일관성(consistency) 및 합성적 특성 기반 정성적, 정량적 분석을 수행하였다. 분석 결과, 영상융합 알고리즘 중 GSA가 공간 유사도를 나타내는 평가지수에서 가장 높은 수치를 보였으며, 분광 유사도를 나타내는 지수들은 PSGAN_RD 모델의 정확도가 가장 높았다. 융합 영상의 공간 및 분광 특성을 모두 고려한다면 PSGAN_RD 모델이 천리안위성 2A호 산출물 제작에 가장 최적일 것으로 판단하였다.

• 기술사
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• 제30권6호
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• pp.144-152
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• 1997

Development of diamond wheel with fine grains and multi-pore structures were newely attempted to be studied in this paper. Wheels, that are employed for the smooth and mirrow finishing of die materials such as tungsten carbide alloy using tool and die materials, must have both performances to remove tool marks efficiently and to contact elastically with curved surfaces. Diamond abrasive grains were bonded firmly by a melamine to prevent the decrease of machining efficiency due to grain sinking within the bond materials. Also, highly foamed structures were developed to increase the flexibility of the wheel, and to induce active self-sharpening by increasing contact pressure between the wheel and work sufaces. In this paper, melamine-bonded diamond wheels are trial manufactured, then the forming method of wheels are explained.

• 대한전자공학회논문지
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• 제26권9호
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• pp.1410-1419
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• 1989

In this paper, we present a new synthetic high coding method which gives high image compression ratio. Given an image, only its low-pass component is transmitted by DCT coding` the high-pass component is not transmitted but synthesized using edge sharpening on the reconstructed low-pass image at the receiver. For the DCT coding which is used to encode the low-pass image, we used an improved version of Cox's variance estimator. Also, introduced are new image quality measures called GSNR and EPR which emphasize perceptual aspects of image quality. Experimental results show that the performance of the proposed synthetic high coding is better in various quality measures than that of Cox's adaptive transform coding. Also, it yields acceptable image quality with neither apparent block effect nor visible granular noise even at high compression ratio of about 30:1.

• 한국생산제조학회지
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• 제7권2호
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• pp.100-107
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• 1998

Diamond wheels with fine grains and multi-porous structures are newely trial developed for smoothing and mirror finishing materials. Grinding wheel must have performed both to remove tool marks efficienitly and to contact elastically with curved surfaces, that are employed for ultra precision and high performance grinding of difficult-to materials such as tungsten carbide alloy using tool and die materials, Diamond grains are bonded by a melamine resin to prevent the decrease of machining efficiency due to grain sinking within the bond materials. Also, highly foamed structures are developed to increase the flexibility of the grinding wheel, and to induce self-sharpening by increasing contact pressure between the grinding wheel and workpiece surfaces. In this paper, melamine-bonded diamond wheels try to manufacture, then the forming method of grinding wheel are suggested, and the grinding characteristics of melamine-bonded diamond grinding wheel are also illustrated.

• 대한기계학회논문집A
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• 제21권12호
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• pp.2172-2178
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• 1997

Development of diamond wheel with fine grains and multi-pore structures were newely attempted. Wheels, that are employed for ultra precision and high performance grinding of difficult-to materials such as tungsten carbide alloy using tool and die materials, must have both performances to remove tool marks efficiently and to contact elastically with curved surfaces. Diamond grains were bonded firmly by a melamine resin to prevent the decrease of machining efficiency due to grain sinking within the bond materials. Also, highly foamed structures were developed to increase the flexibility of the wheel, and to induce active self-sharpening by increasing contact pressure between the wheel and work surfaces. In this paper, melamine-bonded diamond wheels are trial manufactured, then the forming method of wheels are suggested, and the grinding characteristics of wheels are also illustrated.

• Journal of information and communication convergence engineering
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• 제8권4호
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• pp.405-410
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• 2010

Image processing operations like smoothing and edge detection, and many more are very widely used in areas like Computer Vision. We classify the image processing domain as seven branches-image acquirement and output, image coding and compression, image enhancement and restoration, image transformation, image segmentation, image description, and image recognition and description. We implemented algorithms of gaussian smoothing, laplace sharpening, image contrast effect, image black and white effect, image fog effect, image bright and dark effect, image median filter, and canny edge detection. Such experimental results show the figures respectively.

• ETRI Journal
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• 제33권2호
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• pp.169-175
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• 2011

This paper presents a double-sharpened decimation filter based on the application of a Kaiser and Hamming sharpening technique for multistandard wireless systems. The proposed double-sharpened decimation filter uses a pre-droop compensator which improves the passband response of a conventional cascaded integrator-comb filter so that it provides an efficient sharpening performance at half-speed with comparison to conventional sharpened filters. In this paper, the passband droop characteristics with compensation provides -1.6 dB for 1.25 MHz, -1.4 dB for 2.5 MHz, -1.3 dB for 5 MHz, and -1.0 dB for 10 MHz bandwidths, respectively. These results demonstrate that the proposed double-sharpened decimation filter is suitable for multistandard wireless applications.

• 대한원격탐사학회지
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• 제23권5호
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• pp.347-353
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• 2007

Recently, $Gonz\acute{a}lez-Aud\acute{i}cana$ et al. proposed the substitute wavelet intensity(SWI) method which provided a solution based on the intensity-hue-saturation(IHS) method for the fusing of panchromatic(PAN) and multispectral(MS) images. Although the spectral quality of the fused MS images is enhanced, this method is not efficient enough to quickly merge massive volumes of data from satellite. To overcome this problem, we introduce a new SWI method based on a fast IHS transform to implement efficiently as an alternative procedure. In addition, we show that the method is well applicable for fusing IKONOS PAN with MS images.

• 한국정밀공학회지
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• 제10권3호
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• pp.220-230
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• 1993

Photoelastic isochromatic fringes related to the difference of principal stresses have some bandwidth whose light intensities are not constant and asymmetrical in experimental images. Hence, it is difficult to measure fringe order accurately at a data point by visual observation. In this study, a method of fringe sharpening, which can extract shapened lines from both full-and half-order fringes by digital image processing, is developed. To test the method, various simple photelastic fringe patterns are simulated and their images are processed to yield sharpened lines. The method is then applied to general problems such as images of a circular disk compressed by diametrically concentrated loads and a circular cylinder sybject to internal pressure. The procedure is proved to be capable of extracting sharpened lines accurately from photoelastic isochromatic fringes.

• 비파괴검사학회지
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• 제19권3호
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• pp.200-206
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• 1999

광탄성법을 이용하여 인장하중을 받는 곡선보의 중앙에서 하중축과 직교하는 일직선상에 축방향 응력성분을 측정하였다. 광탄성 데이터의 정밀 측정을 위하여 영상처리 시스템을 이용, 원래의 프린지를 명시야 배열과 암시야 배열의 등색선프린지로부터 2배로 증식시키고 세선처리를 하였다. 세선처리된 광탄성 영상으로부터 1/4차수(N=0. 1/4, 2/4. 3/4. 1, 5/4...)마다 프린지 차수를 읽을 수 있으므로 정확한 위치에서 정량적인 측정이 가능하다. 광탄성 실험에서 곡선보의 인장 하중을 3종류로 변화하였을 때 이론식에 의한 응력분포와 일치하는 경향을 나타냈으나, 장탄성법에 의한 측정결과는 이론값과 8%이내의 차이가 나타났다. 이러한 원인은 광탄성 시험편 가공시 하중축과 치수가 이론식에 적용된 조건과 다소 상이한 것으로 판단되며, 정밀하게 가공된 시험편을 사용하여 측정할 경우 실험에 의한 오차는 감소될 것으로 추정된다. 이 실험으로부터 광탄성법에 의한 응력측정시 프린지 증식 및 세선처리 기법을 적용할 경우 정밀한 응력측정이 가능함을 확인할 수 있었다.