• 전자공학회논문지CI
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• 제46권4호
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• pp.94-101
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• 2009

본 논문은 냉각형 적외선(infrared focal plane array; IRFPA) 영상시스템에서 하드웨어 뉴럴 네트워크를 이용한 실시간 고정패턴잡음 제어를 위해 고속 DSP & FPGA 기반의 H/W 설계 방법을 제안한다. 고정패턴잡음은 검출기의 불균일 보정처리후에도 관측영상의 온도분포 변화에 의해 발생한다. 이것은 열상 화질의 저하뿐만 아니라 다른 응용에도 문제되는 중요한 요소이다. 냉각형 적외선 영상시스템의 신호처리구조는 저온, 상온, 고온의 3개 테이블을 기준으로 이득(gain) 값과 편차(offset) 값을 연산한다. 제안된 방법은 3개 편차 테이블에서 각각 교차되는 영역을 세분화하여 가상의 테이블을 만들고, 입력 영상의 구분된 3개 영역에서 영상의 평균값으로 하드웨어 뉴럴 네트워크의 가중치 값을 조정하여 최적의 온도구간을 선정한다. 이와 같은 방법은 영상의 평균값으로부터 저온, 상온, 혹은 고온의 이득, 편차 테이블을 연산하고, 운용 중에 지속적으로 편차 보상을 적용하지 않아도 된다. 따라서 제안된 방법은 실시간 처리로 관측영상의 온도분포 변화에 의해 발생하는 고정패턴잡음을 제어하여 영상화질의 개선된 결과를 보였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.530-532
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• 2007

Multi-Spectral Camera(MSC) is a main payload on the KOMPSAT-2 satellite to perform the earth remote sensing. The MSC instrument has one(1) channel for panchromatic imaging and four(4) channel for multi-spectral imaging covering the spectral range from 450nm to 900nm using TDI CCD Focal Plane Array (FPA). The compression method on KOMPSAT-2 MSC was selected and used to match EOS input rate and PDTS output data rate on MSC image data chain. At once the MSC performance was carefully handled to minimize any degradation so that it was analyzed and restored in KGS(KOMPSAT Ground Station) during LEOP and Cal./Val.(Calibration and Validation) phase. In this paper, on-orbit image data chain in MSC and image data processing on KGS including general MSC description is briefly described. The influences on image performance between on-board compression algorithms and between performance restoration methods in ground station are analyzed and discussed.

• 한국정밀공학회지
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• 제14권5호
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• pp.60-65
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• 1997

This paper proposes a profilometry system for precise surface contouring of 3D objects using a direc- tionally magnified image of a laser light stripe. The resolution of this system can be improved several times comparad with that of conventional systems without loss of spatial resolution and depth of measurement. A pair of cylindrical lens(a convex lens and a concave lens) are used for a directionally magnified image of a laser light stripe maintaining the same focal plane. Also, image processing procedures for image reconstruc- tions are described.

• 산업기술연구
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• 제5권
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• pp.3-7
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• 1985

Analytical techniques for use with reconnaissance frame photographs are outlined. The first approach is a point-by-point space resection in which the dynamic properties of the camera are taken into account. In the second approach appropriate parameters are added to correct for image distoritions, caused by the focal plane shutter, during the space resection phase. Test results showed that the analytical techniques developed will significantly improve the planimetric and height accuracy obtained by conventional methods.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1338-1340
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• 2009

High resolution three-dimensional integral imaging display is proposed. Each time-multiplexed image is projected with different incident angle on same array of elemental lenses. Those images are collected at different positions in focal plane of lens array, and thus the number of the point light sources increases and their spacing decreases. Therefore, proposed method can create high resolution 3D images.

• 한국분무공학회지
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• 제12권4호
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• pp.191-197
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• 2007

This study presents in-line digital particle holography and its application to spray droplets to measure the characteristics of spray droplets. Several important parameters at the time of hologram recording such as the object distance and the region of laser beam used were verified. The correlation coefficient method with important parameters such as the reconstruction interval and the correlation interval was used for determination of the focal planes of particles. The optimal values of all these parameters are obtained by either numerical simulation of holograms or experiments. Using these optimal parameters, double pulse digital spray holograms in a short time interval were recorded with the synchronization system for the time control. The spatial positions of droplets that are used for the evaluation of the three dimensional droplet velocities can be easily located, which proves the feasibility of the digital holographic technology for measurements of several important features of spray droplets.

• Journal of the Optical Society of Korea
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• 제9권2호
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• pp.79-83
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• 2005

Spatial calibrations have been performed on the Medium-sized Aperture Camera (MAC) of the RazakSAT satellite. Topics discussed in this paper include the measurements of system modulation transfer function (MTF), relative pixel line-of-sight (LOS), and end-to-end imaging tests. The MTF measurements were made by capturing the scanned knife-edge image on a pixel, and an issue in the MTF calculation algorithm is discussed. The method used to place the focal plane at the correct focal position is described, since they make use of MTF measurements. Relative LOS measurements are done by theodolite measurements of the telescope. Qualitative ground test result of end-to-end imaging is given.

• 한국군사과학기술학회지
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• 제7권4호
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• pp.79-86
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• 2004

This paper has presented to the design results of the analog and digital signal processor for the 2nd generation thermal imaging system using $480\times6$ infrared focal plane array In order to correct non-uniformities of detector arrays, we have developed the 2-point correction method using the thermo electric cooler. Additionally, to enhance the image of low contrast and improve the detection capability, we developed the new technique of histogram processing being suitable for the characteristics of contrast distribution of thermal imagery. Through these image processing techniques, we obtained a high qualify thermal image and acquired good result.

• 전자공학회논문지B
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• 제32B권6호
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• pp.886-898
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• 1995

One of the ways to measure the distance in the computer vision is to use the focus and defocus. There are two methods in this way. The first method is caculating the distance from the focused images in a point (MMDFP: the method measuring the distance to the focal plane). The second method is to measure the distance from the difference of the camera parameters, in other words, the apertures of the focal planes, of two images with having the different parameters (MMDCI: the method to measure the distance by comparing two images). The problem of the existing methods in MMDFP is to decide the thresholding vaue on detecting the most optimally focused object in the defocused image. In this case, it could be solved by comparing only the error energy in 3x3 window between two images. In MMDCI, the difficulty is the influence of the deflection effect. Therefor, to minimize its influence, we utilize two differently focused images instead of different aperture images in this paper. At the first, the amount of defocusing between two images is measured through the introduction of regularization and then the distance from the camera to the objects is caculated by the new equation measuring the distance. In the results of simulation, we see the fact to be able to measure the distance from two differently defocused images, and for our approach to be robuster than the method using the different aperture in the noisy image.

• 비파괴검사학회지
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• 제25권2호
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• pp.74-80
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• 2005

물체의 형상검사를 위한 검사 방법 가운데 광삼각법을 이용한 레이저 삼각검사 방식은 원격 비접촉식의 고정밀, 고속 측정이 가능하다는 장점이 있다. 이러한 레이저 삼각측정 방식은 평면뿐만 아니라 경사면에 위치한 홀의 길이를 측정하는데 이용하고 있다. 그러나 기존의 방식으로는 렌즈의 초점 거리가 정해져 있었으므로 한정된 영역만을 측정할 수 있다는 단점이 있었다. 이러한 문제는 CCD 카메라와 측정 대상체 사이의 거리를 변화시키는 간단한 방법으로 해결할 수 있다. 이를 원리로 좀더 효율적인 방식을 채택한 것이 가변적인 초점 거리를 갖는 줌 렌즈를 사용하는 방법이다 주 논문에서는 가변적인 초점 거리를 갖는 줌렌즈를 사용함으로써 측정 물체의 크기에 따라 렌즈 배율을 최적화하여 개선된 분해능을 갖는 형상측정 시스템을 제안하였고 정밀도의 향상을 실험적으로 실증하였다.