• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.23-28
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• 2021

Augmented reality is a technique for combining virtual images into real life by showing information of virtual 3D objects on top of a real-world environment (Azuma et al., 2001). This study is an augmented reality-based educational content delivery device that receives user input that selects either a preset object or a photographed object for augmented reality-based training; It includes a three-dimensional design generation unit that generates a stereoscopic model of the augmented reality environment from an object, a three-dimensional view of the scene, a disassembly process of the developing road from a three-dimensional model, and a content control unit provided by the user terminal by generating educational content including a three-dimensional model, a scene chart, a scene, a decomposition process, and a coupling process to build a coupling process from the scene to the three-dimensional model in an augmented reality environment. The next study provides a variety of educational content so that children can use AR technology as well as shapes to improve learning effectiveness. We also believe that studies are needed to quantitatively measure the efficacy of which educational content is more effective when utilizing AR technology.

• Journal of the Optical Society of Korea
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• 제5권4호
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• pp.140-145
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• 2001

We present a new method of volumetric interferometer, which is intended to measure the three-dimensional coordinates of a moving object in a simultaneous way with a single optical setup. The method is based on the principles of phase-measuring interferometry with phase shifting. Two diffraction point sources, which are made of the polished ends of single-mode optical fibers are embedded on the object. Two spherical wavefronts emanate from the diffraction point sources and interfere with each other within the measurement volume. One wavefront is phase-shifted by elongating the corresponding fiber using a PZT extender. A CCD array sensor fixed at the stationary measurement station detects the resulting interference field. The measured phases are then related to the three-dimensional location of the object with a set of non-liner equations of Euclidean distance, from which the complete set of three-dimensional spatial coordinates of the object is determined through rigorous numerical computation based upon the least square error minimization.

• 치과방사선
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• 제28권2호
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• pp.363-385
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• 1998

In orthodontics and orthognathic surgery. cephalogram has been routine practice in diagnosis and treatment evaluation of craniofacial deformity. But its inherent distortion of actual length and angles during projecting three dimensional object to two dimensional plane might cause errors in quantitative analysis of shape and size. Therefore, it is desirable that three dimensional object is diagnosed and evaluated three dimensionally and three dimensional CT image is best for three dimensional analysis. Development of clinic necessitates evaluation of result of treatment and comparison before and after surgery. It is desirable that patient that was diagnosed and planned by three dimensional computed tomography before surgery is evaluated by three dimensional computed tomography after surgery. too. But Because there is no standardized normal values in three dimension now and three dimensional Computed Tomography needs expensive equipments and because of its expenses and amount of exposure to radiation. limitations still remain to be solved in its application to routine practice. If postoperative three dimensional image is constructed by pre and postoperative lateral and postero-anterior cephalograms and preoperative three dimensional computed tomogram. pre and postoperative image will be compared and evaluated three dimensionally without three dimensional computed tomography after surgery and that will contribute to standardize normal values in three dimension. This study introduced new method that computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms. and for validation of new method. in four cases of dry skull that position of mandible was displaced and four patients of orthognathic surgery. computer-simulated three dimensional image and actual postoperative three dimensional image were compared. The results were as follows. 1. In four cases of dry skull that position of mandible was displaced. range of displacement between computer-simulated three dimensional images and actual postoperative three dimensional images in co-ordinates values was from -1.8 mm to 1.8 mm and 94％ in displacement of all co-ordinates values was from -1.0 mm to 1.0 mm and no significant difference between computer-simulated three dimensional images and actual postoperative three dimensional images was noticed(p>0.05). 2. In four cases of orthognathic surgery patients, range of displacement between computer­simulated three dimensional images and actual postoperative three dimensional images in coordinates values was from -6.7 mm to 7.7 mm and 90％ in displacement of all co-ordinates values was from -4.0 to 4.0 mm and no significant difference between computer-simulated three dimensional images and actual postoperative three dimensional images was noticed(p>0.05). Conclusively. computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms. Therefore. potentiality that can construct postoperative three dimensional image without three dimensional computed tomography after surgery was presented.

• 한국멀티미디어학회논문지
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• 제20권8호
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• pp.1200-1207
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• 2017

Sensors in a smartphone can be used to measure various physical quantities. In this paper, we propose an object localization scheme in a three dimenstional using a smart phone. The proposed scheme estimates the location of an object by observing it from several different points. The direction to the target object and the locations of the observation points are collected at each observation point using the location sensor and the orientation sensor in the smartphone. Based on these observations, the proposed scheme derives three dimensional line of sight vectors and estimates the location of the target object that minimizes the estimation error. We implemented the proposed scheme on an Android smartphone and tested its performance by estimating the height of a building and characteristics of the proposed approach.

• 전기학회논문지
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• 제56권1호
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• pp.167-173
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• 2007

This paper describes a redundancy resolution based method for determining an optimal initial configuration of a humanoid robot for holding an object. There are three important aspects for a humanoid robot to be able to hold an object. Those three aspects are the reachability that guarantees the robot to reach the object, the stability that guarantees the robot to remain stable while moving or holding the object, and the manipulability that makes the robot manipulate the object dexterously. In this paper, a humanoid robot with 20 degrees of freedom is considered. The humanoid robot is kinematically redundant and has infinite number of solutions for the initial configuration problem. The complex three-dimensional redundancy resolution problem is divided into two simple two-dimensional redundancy resolution problems by incorporating the symmetry of the problem, robot's moving capability, and the geometrical characteristics of the given robot. An optimal solution with respect to the reachability, the stability, and the manipulability is obtained by solving these two redundancy resolution problems.

• Journal of Computational Design and Engineering
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• 제1권2호
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• pp.96-102
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• 2014

In the field of design and manufacturing, there are many problems with managing dynamic states of three-dimensional (3D) objects. In order to solve these problems, the four-dimensional (4D) mesh model and its modeling system have been proposed. The 4D mesh model is defined as a 4D object model that is bounded by tetrahedral cells, and can represent spatio-temporal changes of a 3D object continuously. The 4D mesh model helps to solve dynamic problems of 3D models as geometric problems. However, the construction of the 4D mesh model is limited on the time-series 3D voxel data based method. This method is memory-hogging and requires much computing time. In this research, we propose a new method of constructing the 4D mesh model that derives from the 3D mesh model with continuous rigid body movement. This method is realized by making a swept shape of a 3D mesh model in the fourth dimension and its tetrahedralization. Here, the rigid body movement is a screwed movement, which is a combination of translational and rotational movement.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.205-208
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• 2005

This research is aimed at the development of a software that predicts the surface temperature profiles of three-dimensional objects on the ground considering the spectral solar radiation through the atmosphere. The thermal modelling is essential for identifying the objects on the scenes obtained from the satellites. And the temperature distribution on the objects is necessary to obtain their infrared images in contrast to the background. We developed a software that could be used to model the thermal problems of the ground objects irradiated by the spectral solar radiation. This software can be used to handle the conduction within the object as a one-dimensional mode into the depth or as a three-dimensional mode through the media. LOWTRAN7 is used to model the spectral solar radiation including the direct and diffuse solar radiances. In this paper, temperature distributions on the objects obtained by using the one-dimensional and the three-dimensional thermal models are compared with each other to examine the applicability of the relatively easy-to-apply one-dimensional model.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1302-1305
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• 1997

A new approach to the three-dimensional measurement of the object surface and moving particles is introduced. A single TV camera with an apparatus to add the circular bias to the image enables us to record the three-dimensional information of measuring points as streaks on a single image. Every shaped of the streak on the image plane is related to the position of the measuring point. the information is extracted form the image using an image processign technique.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.50-50
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• 2000

In this paper, a new measuring system is :proposed which can measure the fine 6-DOF displacement of rigid bodies. Its measurement principle is based on detection of laser beam reflected from a specially fabricated mirror that looks like a triangular pyramid having an equilateral cross-sectional shape. The mirror has three lateral reflective surfaces inclined 45$^{\circ}$ to its bottom surface. We call this mirror 3-facet mirror. The 3-facet mirror is mounted on the object whose 6-DOF displacement is to be measured. The measurement is operated by a laser-based optical system composed of a 3-facet mirror, a laser source, three position-sensitive detectors(PSD). In the sensor system, three PSDs are located at three corner points of a triangular formation, which is an equilateral triangular formation tying parallel to the reference plane. The sensitive areas of three PSDs are oriented toward the center point of the triangular formation. The object whose 6-DOF displacement is to be measured is situated at the center with the 3-facet mirror on its top surface. A laser beam is emitted from the laser source located at the upright position and vertically incident on the top of the 3-fatcet mirror. Since each reflective facet faces toward each PSD, the laser beam is reflected at the 3-facet mirror and splits into three sub-beams, each of which is reflected from the three facets and finally arrives at three PSDs, respectively. Since each PSD is a 2-dimensional sensor, we can acquire the information on the 6-DOF displacement of the 3-facet mirror. From this principle, we can get 6-DOF displacement of any object simply by mounting the 3-facet mirror on the object. In this paper, we model the relationship between the 6-DOF displacement of the object and the outputs of three PSDs. And, a series of simulations are performed to demonstrate the effectiveness of the proposed method. The simulation results show that the proposed sensing system can be an effective means of obtaining 3-dimensional position and orientation of arbitrary objects.

• 정보교육학회논문지
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• 제12권4호
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• pp.395-404
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• 2008

초등학교 수학과 입체도형 학습은 구체물을 활용한 구체적 조작을 통해서 추상적인 입체도형을 직관적으로 이해하도록 돕는 다양한 활동이 필요하다. 입체도형 학습에 있어 구체물의 활용은 효과적이지만, 구체물에서는 확인이 어려운 전개도나 다양한 형태의 입체도형 등은 컴퓨터의 반구체물을 활용하는 것이 효과적이다. 또한 컴퓨터를 활용하게 되면 방과 후에도 같은 학습 자료를 학생들이 활용할 수 있어서 구체물을 활용한 학습의 한계를 보완할 수 있다. 본 연구에서는 플렉스와 플래시를 개발도구로 사용하여 초등학생 수준에서 쉽게 조작하고 사용할 수 있도록 학습 어플리케이션을 개발하였다. 본 연구에서 개발한 입체도형 학습 어플리케이션 활용을 통해 학생들의 직관적이고 자유로운 탐색 및 구체물의 보완, 학습 흥미유발 등의 효과가 기대된다.