• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.10
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• pp.902-909
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• 2015

In this paper, monovision based relative navigation for a satellite proximity operation is studied. The chaser satellite only uses one camera sensor to observe the target satellite and conducts image tracking to obtain the target pose information. However, by using only mono-vision, it is hard to get the depth information which is related to the relative distance to the target. In order to resolve the well-known difficulty in computing the depth information with the use of a single camera, the active contour method is adopted for the image tracking process. The active contour method provides the size of target image, which can be utilized to indirectly calculate the relative distance between the chaser and the target. 3D virtual reality is used in order to model the space environment where two satellites make relative motion and produce the virtual camera images. The unscented Kalman filter is used for the chaser satellite to estimate the relative position of the target in the process of glideslope approaching. Closed-loop simulations are conducted to analyze the performance of the relative navigation with the active contour method.

• Smart Media Journal
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• v.13 no.3
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• pp.18-26
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• 2024

Road surface monitoring is essential for maintaining road environment safety through managing risk factors like rutting and crack detection. Using autonomous driving-based UGVs with high-performance 2D laser sensors enables more precise measurements. However, the increased energy consumption of these sensors is limited by constrained battery capacity. In this paper, we propose a fusion sensor system for efficient surface monitoring with UGVs. The proposed system combines color information from cameras and depth information from line laser sensors to accurately detect surface displacement. Furthermore, a dynamic sampling algorithm is applied to control the scanning frequency of line laser sensors based on the detection status of monitoring targets using camera sensors, reducing unnecessary energy consumption. A power consumption model of the fusion sensor system analyzes its energy efficiency considering various crack distributions and sensor characteristics in different mission environments. Performance analysis demonstrates that setting the power consumption of the line laser sensor to twice that of the saving state when in the active state increases power consumption efficiency by 13.3% compared to fixed sampling under the condition of λ=10, µ=10.

• Journal of Aerospace System Engineering
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• v.13 no.6
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• pp.9-16
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• 2019

The experiment on the liquid jet in crossflow in supersonic BFS (backward-facing step) flow was conducted to investigate the mixing characteristics. The working fluids are nitrogen and water. The shadow graph technique was used to visualize the flow field. Images captured by the high-speed camera were applied to analyze the flow phenomena. The liquid jet was injected at the re-circulation zone created by the supersonic jet flow. Experimental conditions are defined based on the pressure of the nitrogen gas chamber and pressurized liquid tank. In respective cases, the penetration depth of liquid jet and location of the Mach disc were observed to be proportional to the momentum ratio of gas and liquid jets.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.5
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• pp.42-53
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• 2000

Efficient implementation of pre-filtering has been an important issue in video sequence coding, because it can remove camera noise and improve coding efficiency dramatically This paper introduces a novel pre-filtering scheme that is performed inside a video encoder The proposed pre-filtering is based on the approximated generalized Wiener filtering and two-dimensional discrete cosine transform (DCT) factorization. and is achieved by scaling the DCT coefficients of original image blocks for intra block coding and those of motion-compensated error blocks for inter block coding, respectively Even though the pre-filtering operation is embedded in a video encoder, its additional computational complexity is marginal compared to the encoding process, and the overall architecture of the conventional video encoder is maintained In spite of its simplicity, the proposed pre-filtering scheme provides good filtering and coding performance for noisy video sequences.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.5 s.305
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• pp.19-26
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• 2005

In this paper, a new method for obtaining three-dimensional shape of an object by measuring relative blur between images using wavelet analysis has been described. Most of the previous methods use inverse filtering to determine the measure of defocus. These methods suffer from some fundamental problems like inaccuracies in finding the frequency domain representation, windowing effects, and border effects. Besides these deficiencies, a filter, such as Laplacian of Gaussian, that produces an aggregate estimate of defocus for an unknown texture, can not lead to accurate depth estimates because of the non-stationary nature of images. We propose a new depth from defocus (DFD) method using wavelet analysis that is capable of performing both the local analysis and the windowing technique with variable-sized regions for non-stationary images with complex textural properties. We show that normalized image ratio of wavelet power by Parseval's theorem is closely related to blur parameter and depth. Experimental results have been presented demonstrating that our DFD method is faster in speed and gives more precise shape estimates than previous DFD techniques for both synthetic and real scenes.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.21.2-21.2
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• 2011

2010년 11월 05일부터 11월 29일 중 총 12일간 진천 소재 충북대학교 천문대의 60cm 반사망원경과 ST-8 CCD 카메라를 이용하여 BD And의 BVR CCD 측광 관측을 수행하여 처음으로 BVR 광도 곡선을 완성하였다. 또한, 극심시각 결정을 위한 측광관측이 레몬산 천문대 1m 반사망원경과 충북대학교 천문대의 35cm 망원경으로 수행되었다. 우리의 관측과 SWASP 관측을 통하여 모두 31개의 극심시각을 새로이 결정하였다. 새로운 관측은 이 별의 공전주기가 이전까지 알려진 0.4629일이 아니라 그 두 배인 0.9258일이며, 기산점도 반주기 바뀌어야 함을 보여 준다. BD And의 광도요소를 Min I = HJD 2434962.8602 + 0.d9258054 E으로 새롭게 개정하였다. 이 광도요소로 작성한 우리의 BVR 광도곡선은 제1식과 제2식의 깊이가 거의 비슷하며, 식바깥 부분에 잘 발달된 파형 모양을 보인다. 이는 BD And가 짧은 주기의 RS CVn형 식쌍성임을 나타내는 것이다. 우리의 극심시각을 포함한 총 144개의 극심시각에 대한 (O-C)도를 작성한 결과, BD And의 공전주기가 규칙적으로 변화하는 것을 발견하였다. 이 변화를 보이지 않는 제3천체에 의한 광시간 효과로 가정하여, 궤도이심율이 0.78이며, 9.19년의 주기를 가진 광시간 궤도를 결정하였다.우리의 광도곡선을 2003년 Wilson-Devinney 쌍성 모형으로 분석하여 광도곡선 해를 질량비 q=1.1822, 궤도경사각 i=$86.^{\circ}16$, $T_1$=6358(K), $T_2$=6250(K), $r_1$=1.117(Rsun), $r_2$=1.321(Rsun)와 같이 산출하였다. 식바깥에서 나타나는 파형 모양의 변화는 주성의 표면에 매우 큰 흑점으로 잘 설명되며, BVR 광도곡선에서 각각 전체 광도의 각 6.4%, 8.1%, 9.9%에 해당되는 제3 광도가 검출되었다. 이는 주기연구에서 제안된 제3천체의 존재 가능성을 더 공고히 한다.

• Journal of Korea Multimedia Society
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• v.17 no.2
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• pp.132-142
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• 2014

Stereo camera is drawing attention as an essential sensor for future intelligence robot system since it has the advantage of acquiring not only distance but also other additive information for an object. However, it cannot match correlated point on target image for low textured region or periodic patterned region such as wall of building or room. In this paper, we propose a stereo matching technique that increase the matching performance by fusing belief propagation stereo matching algorithm and local distance measurements of 2D-laser range finder in order to overcome this kind of limitation. The proposed technique adds laser measurements by referring quad-tree based segment information on to the local-evidence of belief propagation stereo matching algorithm, and calculates compatibility function by reflecting over-segmented information. Experimental results of the proposed method using simulation and real test images show that the distance information for some low textured region can be acquired and the discontinuity of depth information is preserved by using segmentation information.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.140-154
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• 2011

Through this thesis, I intended to analyze superhero action thriller through that achieved in art and box office after the film release. I would to access about it centering around directing viewpoint. of Christoper Nolan is evaluate as 'upgraded excellent action thriller'that have remarkable theme and excellent visual. Analysis of directing'll classify both contents and form. See about contents... theme of existential dilemma about the good and the evel, characters who is grew more powerful, and deeper than Batman series in old times. the fifth plot, especially dramatic plot by Joker's game, and various irony and motif. About form... efficient use of IMAX camera, prominence of action directing about car chase and fighting... better editing and music and art than former super hero series. The most important merit of is it's a philosophical theme. It is dipicted very seriously and successfully. First of all, the film has more advanced technique power and new directing style.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.629-638
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• 2011

Mobile game have an advantage of mobility, portability, and simple interface. These advantages are useful for gesture recognition based game which should not have much content quantity and complex interface. This paper suggests gesture recognition based mobile game content with user movement could be applied directly to the mobile game wherever recognition system is equipped. Gesture is recognized by obtaining user area in image from the depth image of TOF camera and going through SVM(Support Vectorn Machine) using EOH(Edge Of Histogram) features of user area. And we confirmed that gesture recognition can be utilized to user input of mobile game content. Proposed technique can be applied to a variety of content, but this paper shows a simple way of game contents which is consisted of moving and jumping newly.

• The Journal of the Korea Contents Association
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• v.7 no.8
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• pp.152-162
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• 2007

Subject of this Study is focused on set design for short animation, GHOST, made and presented by animation studio, BEYOND PROSCENIUM. Sets in animation have several functions. First, sets are a playground that character can play to lead a story. Second, sets explain background, which is time and space. Third, sets can visualize metaphorical meaning or symbolic system in animation. To obtain final design that is sufficient to those functions, this study analyzes the case that metaphorical and symbolic meaning from scenario is how to apply into set design also, mentions the method that designer multiply considers character, property and composition from the camera and movement from those elements. Set designers for animation should have ability that simultaneously considers so many elements and they need design skills to create it.