• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.407-407
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• 2000

For acquisition of 3-Dimensional information in real space, stereo vision system is suitable. In the stereo system, 3D real world position is derived from translation of coordinates between cameras and world. Thus, to use stereo vision, it is needed to construct a precise system which provides kinematically precise translation between camera and world coordinate, in spite of intricacy and hardness. So much cost and time should be spent to build the system. In this paper, facilely to solve previous problem, a method which can easily obtain 3D informations using reference objects and RSD(Relative Stereo Disparity) is proposed. Instead of direct computation of position with translation of coordinates, only relative stereo disparity in stereo pair of image is used to find the reference depth of objects, and real 3D position is computed with initial condition of reference objects. In computation, subpixel resolution is involved to find the display for accuracy. To find the RSD, corresponding points are calculated in subpixel resolution. So the result in experiemnt will be shown that subpixel resolution is more accurate than 1 pixel resolution.

• 아동학회지
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• 제25권6호
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• pp.1-13
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• 2004

The purposes of this study were to investigate whether there were differences in the young children's abilities to use spatial coordinates and to represent spatial locations by children's age and sex, and to examine the relationship between these two abilities. It also explored whether the young children could use coordinates as the frames of reference for representing spatial locations. Seventy 5- and 6-year-old children from two kindergartens in Seoul and in Bucheon participated in this study. Results indicated that there were statistically significant differences between age groups on the children's ability to use spatial coordinates and to represent spatial locations. However, there were no significant differences between boys and girls on these two abilities. A positive correlation was found between theses two abilities of using spatial coordinates and representing spatial locations. Most of the young children used landmarks as the frames of reference to represent spatial locations while some of the children were partially able to use spatial coordinates. Twenty percent of 6-year-old children were fully able to use spatial coordinates as the frames of reference to represent spatial locations.

• 한국측량학회지
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• 제23권3호
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• pp.273-282
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• 2005

인공위성기술의 비약적인 발전은 각종 공간정보의 취득과 이를 응용하는 다양한분야에 광범위하게 이용되고 있다. 특히 GPS를 이용한 위치결정은 국가 기준계가 세계좌표계로 전환되는 시점을 맞이하여 더욱 활성화 될 전망이다. 현재 국토지리 정보원에서 발급하는 삼각점에 대한 성과는 신성과와 구성과로 구분하고 있고 2007년부터는 전면 세계좌표계로 전환할 예정에 있다. 현재 제주지역의 삼각점은 최초, 복구 또는 재설한 삼각점 성과 차이로 인해 측량자 들이 그 성과를 이용함에 있어 많은 혼란을 초래하고 있다. 따라서 본 연구는 제주지역의 현행삼각점간 부합관계를 점검하기 위해 1, 2등 삼각점을 기준으로 최초 측량 당시의 측지망을 재 구성하여 GPS 관측을 수행하였다. 관측 후 성과분석을 통해 삼각점간 부합되는 안정점을 추출하고 제주지역에 적합한 측지기준망을 구축하고 그 활용방안을 제시하였다. .

• 대한기계학회논문집A
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• 제29권4호
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• pp.534-539
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• 2005

Nodal displacements are referred to the initial configuration in the total Lagrangian formulation and to the last converged configuration in the updated Lagrangian furmulation. This research proposes a relative nodal displacement method to represent the position and orientation for a node in truss structures. Since the proposed method measures the relative nodal displacements relative to its adjacent nodal reference frame, they are still small for a truss structure undergoing large deformations for the small size elements. As a consequence, element formulations developed under the small deformation assumption are still valid for structures undergoing large deformations, which significantly simplifies the equations of equilibrium. A structural system is represented by a graph to systematically develop the governing equations of equilibrium for general systems. A node and an element are represented by a node and an edge in graph representation, respectively. Closed loops are opened to form a spanning tree by cutting edges. Two computational sequences are defined in the graph representation. One is the forward path sequence that is used to recover the Cartesian nodal displacements from relative nodal displacement sand traverses a graph from the base node towards the terminal nodes. The other is the backward path sequence that is used to recover the nodal forces in the relative coordinate system from the known nodal forces in the absolute coordinate system and traverses from the terminal nodes towards the base node. One open loop and one closed loop structure undergoing large deformations are analyzed to demonstrate the efficiency and validity of the proposed method.

• 한국정밀공학회지
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• 제24권10호
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• pp.64-74
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• 2007

Because of the size and environment in the shipbuilding process, the portable type robot is required for the automatic seam tracking. For this reason, the structure of laser sensor should be considered in the initial design step and the coordinate transformation between welding robot and laser sensor, which is joint finder, must be identified exactly and the real time tracking algorithm based on these consideration could be developed. In this research, laser displacement sensor in which its structure is laser beam's vertical projection, is developed to recognize the location of weld joint. In practical applications, however, images of weld joints are often degraded because of the surface specularity or spatter. To overcome the problem, the constrained joint finding algorithm is proposed. In the approach of coordinate conversion rule for the visual feedback control among welding torch, robot body and laser sensor is applied by the same reference point method. In the real time seam tracking algorithms we propose constrained sampling method which uses look ahead distance. The RLS(Recursive Least Square) filter is applied to obtain the smooth tracking path from the sensitive edge data. From the experimental results, we could see the possibility that the developed laser sensor with proposed processing algorithm and real time seam tracking method can be used as a welding under the shipbuilding condition.

• 대한의용생체공학회:의공학회지
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• 제41권5호
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• pp.173-178
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• 2020

Remote control intervention surgery robotic system improves treatment effect on cardiovascular patients and reduces X-ray exposure. However, at the time of the first procedure, CT (computerized tomography) and other ultrasound diagnostic equipment should be used because the operator must insert the cannula directly into the patient's leg. Improvements to this have been un-met-needs of hospitals. In this paper, we developed a system that can insert the cannula intuitively and quickly by displaying blood vessels at a glance through the system using smart wearable glasses. The core development method is as follows. In order to project augmented reality onto the surgical image, CT scan angiography image is extracted and processed. In the process, three CT-Markers are used to create a coordinate system of blood vessel images. Additionally, a reference marker is photographed on a single camera to obtain a camera coordinate system. Since the CT marker and the reference marker are in the same position, 3D registration is performed. In the text, a detailed explanation will be given.

• 대한공간정보학회지
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• 제15권3호
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• pp.41-49
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• 2007

GPS 관측에 의해 구한 기선벡터를 이용하여 평면에서의 삼변망 조정계산에 의하여 지적측량기준점의 베셀좌표를 산출하는 소프트웨어를 개발하고 우리나라 전역 지적측량 기준점의 성과 통일에 활용하였다. GPS 관측점간의 기선 거리를 평면에 전개하는 데에는 PNU95 지오이드모델을 이용하여 지오이드면상의 거리를 산출하고, 다음으로 베셀 타원체상의 좌표에 바탕하여 구한 증대율을 적용하여 평면투영거리를 산출하였다. 우리나라 전역 지적측량기준점의 통일성과를 산출하는 데에는, 우선 자유망조정에 의해 전국 32개소 GPS 상시관측소의 베셀좌표를 산출하고, 다음으로 이들 GPS 상시관측소에다 지적측량기준점과 결합하는 망조정계산을 실시하였다. 그 결과 GPS 기선벡터를 이용하여 현재의 지적기준점 성과를 정비할 경우 전국 어디에서나 점간거리 1ppm 이내에서 일치하는 베셀좌표의 결정이 가능하였다.

• 대한공간정보학회지
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• 제14권1호
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• pp.65-74
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• 2006

인공위성기술의 비약적인 발전은 각종 공간정보의 취득과 이를 응용하는 다양한 분야에 광범위하게 이용되고 있다. 특히 GPS를 이용한 위치결정은 국가 기준계가 세계좌표계로 전환되는 시점을 맞이하여 더욱 활성화 될 전망이다. 현재 국토지리 정보원에서 발급하는 삼각점에 대한 성과는 신성과와 구성과로 구분하고 있고 2007년 부터는 전면 세계좌표계로 전환할 예정에 있다. 현재 제주지역의 삼각점은 최초, 복구 또는 재설한 삼각점 성과 차이로 인해 측량자 들이 그 성과를 이용함에 있어 많은 혼란을 초래하고 있다. 따라서 본 연구는 제주지역의 현행삼각점간 부합관계를 점검하기 위해 1, 2등 삼각점을 기준으로 최초 측량 당시의 재 구성하여 GPS 관측을 수행하였다. 관측 후 성과분석을 통해 삼각점간 부합되는 안정점을 추출하고 제주지역에 적합한 측지기준망을 구축하고 그 활용 가능성를 제시하였다.

• Journal of Astronomy and Space Sciences
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• 제30권4호
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• pp.315-320
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• 2013

Space geodetic techniques can be used to obtain precise shape and rotation information of the Earth. To achieve this, the representative combination solution of each space geodetic technique has to be produced, and then those solutions need to be combined. In this study, the representative combination solution of very long baseline interferometry (VLBI), which is one of the space geodetic techniques, was produced, and the variations in the position coordinate of each station during 7 years were analyzed. Products from five analysis centers of the International VLBI Service for Geodesy and Astrometry (IVS) were used as the input data, and Bernese 5.0, which is the global navigation satellite system (GNSS) data processing software, was used. The analysis of the coordinate time series for the 43 VLBI stations indicated that the latitude component error was about 15.6 mm, the longitude component error was about 37.7 mm, and the height component error was about 30.9 mm, with respect to the reference frame, International Terrestrial Reference Frame 2008 (ITRF2008). The velocity vector of the 42 stations excluding the YEBES station showed a magnitude difference of 7.3 mm/yr (30.2%) and a direction difference of $13.8^{\circ}$ (3.8%), with respect to ITRF2008. Among these, the 10 stations in Europe showed a magnitude difference of 7.8 mm/yr (30.3%) and a direction difference of $3.7^{\circ}$ (1.0%), while the 14 stations in North America showed a magnitude difference of 2.7 mm/yr (15.8%) and a direction difference of $10.3^{\circ}$ (2.9%).

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.788-791
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• 2005

Nodal displacements are referred to the Initial configuration in the total Lagrangian formulation and to the last converged configuration in the updated Lagrangian formulation. This research proposes a relative nodal displacement method to represent the position and orientation for a node in truss structures. Since the proposed method measures the relative nodal displacements relative to its adjacent nodal reference frame, they are still small for a truss structure undergoing large deformations for the small size elements. As a consequence, element formulations developed under the small deformation assumption are still valid fer structures undergoing large deformations, which significantly simplifies the equations of equilibrium. A structural system is represented by a graph to systematically develop the governing equations of equilibrium for general systems. A node and an element are represented by a node and an edge in graph representation, respectively. Closed loops are opened to form a spanning tree by cutting edges. Two computational sequences are defined in the graph representation. One is the forward path sequence that is used to recover the Cartesian nodal displacements from relative nodal displacements and traverses a graph from the base node towards the terminal nodes. The other is the backward path sequence that is used to recover the nodal forces in the relative coordinate system from the known nodal forces in the absolute coordinate system and traverses from the terminal nodes towards the base node. One closed loop structure undergoing large deformations is analyzed to demonstrate the efficiency and validity of the proposed method.