• 수산해양교육연구
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• 제5권2호
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• pp.90-97
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• 1993

Pair trawling is one of the important fishing methods for Korean fisheries, and is working in the western sea of Korea - the Yellow Sea and the East China Sea. On the engine power of the trawlers, 72% of 190 pairs of trawlers were equipped with 450ps class engine, and 21% with 450~750ps and merely 7% with in 750ps class 1980. Thereafter the engine power has grown up, so that 450~750ps occupy 28% and 750ps or more 27% in 1992. Main objective fishes of pair trawling were traditionally flat fishes, so the fundamental shape of pair trawl net was a four - seam net, but by the gradual shortage of flat fishes, roundfishes has been noticed. So the six - seam net which performs high opening of net mouth has been used widely since 1985. In the six - seam net, the length of wing was not so short in the beginning but became short in the later instead of the net pendant elongated, and also the pendant was separated into three pieces according to the change of wing structure. Since the 1990's, the objective fishes has gradually been changed into pelagic fishes, the fishing technique is required to fit the behavior of fishes. So the midwater trawling or the multi -layer trawling became required.

• 방송공학회논문지
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• 제24권6호
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• pp.992-1001
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• 2019

다수의 카메라를 이용하여 취득된 영상을 정합 하여 하나의 넓은 시야각을 가지는 영상을 합성하는 기술이 많은 영역에서 사용되고 있다. 영상의 정합 영역 내에 이동 객체가 등장한 경우 객체의 왜곡 없이 영상을 정합 하기 위하여 움직임 정보를 이용하는 시접선 추정 방법을 제안한다. 기존 시접선 추정 기반 기술들은 영상 외곽선 정보와 시차 등을 이용하여 에너지 함수를 형성하고 시접선을 추정하는 방법을 사용하여 왔으나, 본 논문에서는 프레임 별 외곽선 정보를 이용하여 움직임 정보를 계산하고, 이를 에너지 함수에 반영하여 영상 정합 시 이동 객체의 왜곡을 방지하는 시접선 추정 기술을 제안한다. 또한, 정합 영상의 왜곡 정도를 정량화 할 수 있는 지표를 제안하여 기존 기술과 제안된 방법의 성능 차이를 검증한다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1996년도 특별강연 및 추계학술발표 개요집
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• pp.142-144
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• 1996

This paper discusses the application of infra-red thermography in monitoring the robotic arc welding process, and it's potential for weld bead dimension and seam tracking control. Thermal images illustrating weld pool formation dynamics and heat distribution phenomena are digitized and their characteristics are measured. At each sampling point the maximum depth of penetration is recorded together with additional information regarding weld bead placement in relation to the seam location. Deficiencies such as incomplete penetration and lack of side wall fusion are readily identified and can be remained during the process. The technique can help an increase in productivity and weld quality by minimizing the amount of post process rework and inspection efforts needed otherwise.

• Geomechanics and Engineering
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• 제22권1호
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• pp.1-9
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• 2020

This paper presents an investigation of the ground response of a gob-side gateroad suffering mining stress induced by a 21 m-thick coal seam extraction. A field observation, including entry convergence and stress changes monitoring, was first conducted in the tailgate 8209. The observation results of entry convergence showed that, during the adjacent panel 8210 retreating period, the deformation of the gob-side gateroad experienced a continuous increase stage, subsequently, an accelerating increase stage, and finally, a slow increase stage. However, strong ground response, including roof bending deflection, rib extrusion and floor heave, occurred during the current panel 8209 retreating period, and the maximum floor heave reached 1530 mm. The stress changes within coal mass of the two ribs demonstrated that the gateroad was always located in the stress concentrated area, which responsible for the strong response of the tailgate 8209. Subsequently, a hydraulic fracture technique was proposed to pre-fracture the two hard roofs above the tailgate 8209, thus decreasing the induced disturbance on the tailgate. The validity of the above roof treatment was verified via field application. The finding of this study could be a reference for understanding the stability control of the gob-side gateroad in extra thick coal seams mining.

• 방송공학회논문지
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• 제25권5호
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• pp.685-697
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• 2020

파노라마(Panorama) 및 360도 영상과 같은 몰입형(Immersive) 미디어 영상은 영상 내 공간을 사용자가 직접 방문한 것 같은 현장감을 제공해야하므로 실제 세계의 모습을 사실 그대로 나타낼 수 있어야 한다. 그러나 파노라마 및 360도 영상에서는 촬영 카메라들간의 시차(Parallax)로 인해 사물이 사라지거나 중복해서 나타나는 현상이 나타나며, 이와 같은 시차 왜곡은 사용자의 콘텐츠 몰입을 방해할 수 있다. 이에 따라서, 시차 왜곡을 극복하기 위한 많은 동영상 스티칭 알고리즘이 제안되고 있지만, Object detection 모듈의 낮은 성능과 Seam 생성 방식 등의 제한으로 여전히 시차 왜곡이 발생하고 있다. 이에 본 논문에서는 기존 동영상 스티칭 기술의 제한 사항을 분석하고, 해당 동영상 스티칭 기술의 제한을 극복하기 위하여 LDPM(Local Differential Pixel Mean) 영상 평가를 활용한 동영상 스티칭의 시차 왜곡 검출 및 정정 방법을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권11호
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• pp.5419-5435
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• 2017

The construction of panoramic images on smartphones and low-powered devices is a challenging task. In this paper, we propose a new approach for smoothly stitching images on mobile phones in the presence of moving objects in the scene. Our main contributions include handling moving object problems, reducing processing time, and generating rectangular panoramic images. First, unique and robust feature points are extracted using fast ORB method and a feature matching technique is applied to match the extracted feature points. After obtaining good matched feature points, we employ the non-deterministic RANSAC algorithm to discard wrong matches, and the hommography transformation matrix parameters are estimated with the algorithm. Afterward, we determine precise overlap regions of neighboring images and calculate their absolute differences. Then, thresholding operation and noise removal filtering are applied to create a mask of possible moving object regions. Sequentially, an optimal seam is estimated using dynamic programming algorithm, and a combination of linear blending with the mask information is applied to avoid seam transition and ghosting artifacts. Finally, image-cropping operation is utilized to obtain a rectangular boundary image from the stitched image. Experiments demonstrate that our method is able to produce panoramic images quickly despite the existence of moving objects.

• 대한치과보철학회지
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• 제29권3호
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• pp.87-99
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• 1991

The effect of oven firing on the color stability and surface texture of extrinsic stains used characterization and color modification of metal cermic restoration were studied by comparing different temperatures and techniques. They were autoglaze technique, applied glaze technique, two step low-fusing glaze technique and one step low-fusing glaze technique. Autoglaze technique and applied glaze technique were air-fired to manufacturer's recommended temperature. Two step low-fusing glaze technique is separated staining and overglazing. Thin slurry of stain powder were air-fired to $1500^{\circ}F$, Overglaze powder powder was then mixed with seam medium and air-fired to $170^{\circ}F$. One step low-fusing glaze technique is combined staining and overglazing. Thin slurry of stain and glaze powder were air-fired to $170^{\circ}F$. The obtained results were as fellows. 1. Slightly significant color differences by colorimeter were found between different stain application and fusion techniques(P<0.05). 2. Two step low-fusing glaze method showed the most rough surface, especially ceramco orage stain(P<0.05). 3. Surface roughness increased gradually in order of autoglaze, applied glaze, one step low-fusing glaze but they were not significantly different(P<0.05). 4. When two step low-fusing glaze was applied, both color measurement and surface texture were sinificantly different from other groups(P<0.05).

• 정보처리학회논문지B
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• 제14B권5호
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• pp.351-360
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• 2007

비디오 복원(video completion) 기술은 비디오 영상에서 색상 정보가 없는 픽셀에 적절한 색을 채워 영상을 복원하는 기술이다. 본 논문에서는 움직이는 물체가 서로 교차하는 비디오 영상에서 원하지 않는 물체를 제거하고 이때 발생한 영상 홀(image hole)을 채우는 비디오 복원 기술을 제안한다. 움직이는 카메라에서 획득한 비디오 영상에서 이동하는 두 물체 중 카메라와 가까운 물체를 제거함으로써 가려진 이동물체와 배경에 홀이 발생하게 되고, 이 홀온 다른 프레임들의 정보를 이용하여 채움으로써 새로운 비디오를 생성한다. 입력 영상의 모든 프레임에 대해 각 물체의 중심을 추정하여 물체의 중심을 기준으로 시-공간 볼륨(spatio-temporal volume)을 생성하고, 복셀 매칭(voxel matching)을 통한 시간적 탐색(temporal search)을 수행한 후 두 물체를 분리한다. 가리는 물체 영역으로 판단된 부분을 삭제하고 공간적 탐색(spatial search) 방법을 이용하여 홀을 채워 가려짐이 있는 이동 물체 및 배경을 복원한다. 복원된 영상에서 블렌딩을 통해 솔기(seam)를 제거한다. 비디오카메라로 획득한 두 실영상을 이용하여 실험을 수행한 결과 가려진 물체를 복원한 새로운 비디오 영상을 생성할 수 있었다.

• 대한기계학회논문집A
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• 제20권3호
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• pp.891-900
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• 1996

The vision sensor which is based on the optical triangulation theory with the laser as an auxiliary light source can detect not only the seam position but the shape of seam. In this study, a vision sensor using the scanning laser beam was investigated. To design the vision sensor which considers the reflectivity of the sensing object and satisfies the desired resolution and measuring range, the equation of the focused laser beam which has a Gaussian irradiance profile was firstly formulated, Secondly, the image formaing sequence, and thirdly the relation between the displacement in the measuring surface and the displacement in the camera plane was formulated. Therefore, the focused beam diameter in the measuring range could be determined and the influence of the relative location between the laser and camera plane could be estimated. The measuring range and the resolution of the vision sensor which was based on the Scheimpflug's condition could also be calculated. From the results mentioned above a vision sensor was developed, and an adequate calibration technique was proposed. The image processing algorithm which and recognize the center of joint and its shape informaitons was investigated. Using the developed vision sensor and image processing algorithm, the shape informations was investigated. Using the developed vision sensor and image processing algorithm, the shape informations of the vee-, butt- and lap joint were extracted.

• 복식
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• 제60권10호
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• pp.80-87
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• 2010

The purpose of this study is to develop cultural products containing Korean beauty with modern sense by applying quilting with dyed threat among Korean traditional quilting works. Quilting with dyed thread using various colored thread expresses curve, straight and oblique lines harmoniously, is mainly used to make household goods such as a pouch, a spectacle case and a quilting pocket and a circular pattern, a cross pattern and a geometric pattern are shown in this kind of quilting. As for sewing method, half backstitch and full backstitch are used, and products made by this method are pouches stuffing pads in cotton or silk and quilting it finely to make patterns with various colored threads of stuffing cotton between linings and spectacle cases, a packet of needles and case of spoon and chopsticks which give various feelings according to arrangement of colors. Design of cultural products by applying the beauty of curves of hanbok, sleave-seam of jeogori, trimming line of dangeui. We expect that various cultural products with Korean traditional beauty and modern convenience will be developed continually by introducing the artistic strength of quilting with dyed thread to practical life.