• 대한전자공학회논문지SP
• /
• 제39권1호
• /
• pp.40-48
• /
• 2002

시점을 달리하는 영상으로부터 3차원 장면 복구는 두 영상의 에피폴라 기하구조를 나타내는 F-행렬을 계산함으로서 가능하다. F-행렬을 계산하기 위해 입력으로 주어지는 두 영상의 일치점에는 잘못된 정합점과 같은 잡음을 포함하고 있기 때문에 정확한 F-행렬의 계산은 많은 오류를 가지게 된다. 따라서 본 논문에서는 에피폴라 기하구조에 영향을 미치는 잡음의 종류를 크게 outlier와 미세잡음으로 구분하였다. 상대적으로 에피폴라 기하구조에 영향을 크게 미치는 outlier를 단계적으로 제거시킴으로써 잡음 환경에서도 효과적으로 F-행렬을 계산할 수 있는 SSOR 알고리즘을 제안한다. 제안 알고리즘의 성능 평가를 위해 합성영상과 실 영상에서 실험하였으며 실험결과 제안 알고리즘이 기존의 알고리즘보다 성능이 우수함을 확인하였다.

• Journal of information and communication convergence engineering
• /
• 제13권4호
• /
• pp.275-279
• /
• 2015

There are several methods to record three dimensional (3D) information of objects such as lens array based integral imaging, synthetic aperture integral imaging (SAII), computer synthesized integral imaging (CSII), axially distributed image sensing (ADS), and axially distributed stereo image sensing (ADSS). ADSS method is capable of recording partially occluded 3D objects and reconstructing high-resolution slice plane images. In this paper, we present a computational method for depth extraction of partially occluded 3D objects using ADSS. In the proposed method, the high resolution elemental stereo image pairs are recorded by simply moving the stereo camera along the optical axis and the recorded elemental image pairs are used to reconstruct 3D slice images using the computational reconstruction algorithm. To extract depth information of partially occluded 3D object, we utilize the edge enhancement and simple block matching algorithm between two reconstructed slice image pair. To demonstrate the proposed method, we carry out the preliminary experiments and the results are presented.

• 대한견주관절학회:학술대회논문집
• /
• 대한견주관절학회 2009년도 제17차 학술대회
• /
• pp.74-74
• /
• 2009

The purpose of this study was to estimate force of muscles that constituted the rotator cuff during elevation motion in scapula plane, using a skeletal muscle model and quantitatively evaluate rotator cuff function in vivo. A healthy volunteer was measured with an open MR and CT system at elevation positions in scapula plane (MR: $30^{\circ}$, $60^{\circ}$, $90^{\circ}$, $120^{\circ}$, $150^{\circ}$, CT: $0^{\circ}$). After reconstruction three-dimensional MRI-based and CT-based bone surface models, matched each models with registration technique. Then supraspinatus, infraspinatus, subscapularis, teres minor, deltoid (anterior, middle, posterior portions) represented as plural lines. These lines were proportional to physiologic cross-sectional area (PCSA) and defined straight line to bind origin and insertion. Force of supraspinatus became greatest at $59^{\circ}$ of elevation. Subsequently force of deltoid middle portion became greatest at $89^{\circ}$ of elevation. Infraspinatus and subscapularis were active at the meantime. In addition, supraspinatus was active during elevation. These results resembled clinical finding and were proved force couples that contribute to mobility and stability of shoulder complex.

• 대한조선학회논문집
• /
• 제45권4호
• /
• pp.379-388
• /
• 2008

A hybrid Cartesian/immersed boundary code is expanded to simulate flow field around a three-dimensional body which undergoes large dynamic deformation. Immersed boundary nodes are automatically distributed based on the edges crossing triangles on body boundary. Velocity vectors are reconstructed at those immersed boundary nodes along local normal lines to the boundary. The reconstruction of pressure is avoided using the hybrid staggered/non-staggered grid method. The developed code is validated through comparisons with other results on laminar flow over a sphere. The code is applied to simulate flow around a foil which is attached to a body of revolution and rotates under periodic deformation. The periodic variation of the tip vortex is observed and the effects of the deformation on hydrodynamic force acting on the body are investigated.

• 대한공간정보학회지
• /
• 제14권3호
• /
• pp.13-22
• /
• 2006

3차원 지형공간정보의 활용범위가 확대되면서 다양한 형태와 크기의 건물들이 존재하는 광범위한 도시지역에 대하여 신속하고 정확하게 실세계에 가까운 3차원 건물 모형을 구축하는 기술 개발이 요구되고 있다. 기존의 항공사진이나 고해상 위성영상을 이용한 3차원 도시 지형공간의 구축 연구와는 달리 최근에는 높은 정밀도를 가진 항공 LIDAR 관측 자료를 활용한 3차원 건물 복원에 관한 연구가 활발히 진행되고 있다. 본 연구에서는 Zero-crossing의 특성을 갖는 LoG 연산자를 이용하여 높이별로 건물의 경계선 정보를 추출하고 Douglas-Peucker 알고리즘을 이용하여 경계선을 직선화하여 건물의 경계선을 정제하고 3차원으로 건물을 복원하는 기법을 제안하였다.

• 한국측량학회지
• /
• 제38권5호
• /
• pp.425-433
• /
• 2020

Three-dimensional data has been used for different applications such as robotics, building reconstruction, and so on. 3D data can be generated from an optical camera or a laser scanner. Especially, a wearable multi-sensor system including the above-mentioned sensors is an optimized structure that can overcome the drawbacks of each sensor. After finding the geometric relationships between sensors, georeferencing of the datasets acquired from the moving system, should be carried out. Especially, in an indoor environment, error propagation always causes problem in the georeferencing process. To improve the accuracy of this process, other sources of data were used to combine with LiDAR (Light Detection and Ranging) data, and various registration methods were also tested to find the most suitable way. More specifically, this paper proposed a new process of NDT (Normal Distribution Transform) to register the LiDAR point cloud, with additional information from other sensors. For real experiment, a wearable mapping system was used to acquire datasets in an indoor environment. The results showed that applying the new process of NDT and combining LiDAR data with IMU (Inertial Measurement Unit) information achieved the best result with the RMSE 0.063 m.

• Journal of information and communication convergence engineering
• /
• 제13권2호
• /
• pp.132-138
• /
• 2015

Enlarging the horizontal viewing angle is an important feature of integral imaging monitors. Thus far, the horizontal viewing angle has been enlarged in different ways, such as by changing the size of the elemental images or by tilting the lens array in the capture and reconstruction stages. However, these methods are limited by the microlenses used in the capture stage and by the fact that the images obtained cannot be easily projected into different displays. In this study, we upgrade our previously reported method, called SPOC 2.0. In particular, our new approach, which can be called SPOC 2.1, enlarges the viewing angle by increasing the density of the elemental images in the horizontal direction and by an appropriate application of our transformation and reshape algorithm. To illustrate our approach, we have calculated some high-viewing angle elemental images and displayed them on an integral imaging monitor.

• Journal of Microbiology and Biotechnology
• /
• 제16권10호
• /
• pp.1577-1582
• /
• 2006

Cartilage tissue engineering has emerged as an alternative approach for reconstruction or repair of injured cartilage tissues. In this study, rabbit chondrocytes were cultured in a three-dimensional environment to fabricate a new cartilaginous tissue with the application of tissue engineering strategies based on biodegradable PLGA microspheres. Chondrocytes were seeded on PLGA microspheres and cultured on a rocking platform for 5 weeks. The PLGA microspheres provided more surface area to adhere chondrocytes compared with PLGA sponge scaffolds. The novel system facilitated uniform distribution of the cells on the whole of the PLGA microspheres, thus forming a new cartilaginous construct at 4 weeks of culture. The histological and immunohistochemical analyses verified that the number of chondrocytes and the amount of extracellular matrix components such as proteoglycans and type II collagen were significantly greater on the PLGA microspheres constructs as compared with those on the PLGA sponge scaffolds. Therefore, PLGA microspheres enhanced the function of chondrocytes compared with PLGA sponge scaffolds, and thus might be useful for formation of cartilage tissue in vitro.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
• /
• pp.1424-1426
• /
• 2003

It will be a real good news for the people who were lost their hometown by the construction of a large dam to be restored to the former state. Focused on Cheung-Pyung around where most part were flooded by the Chungju large Dam founded in early 1980s, we used Remote Sensing Technique in this study in order to restore topographical features before the flood with 3 dimensional effects. We gathered comparatively good satellite photos and remotely sensed digital images, then we made a new color image from these and the topographical map which had been made before the flood. This task was putting together two kinds of different timed images. And then, we generated DEM including the outskirts of that area as harmonizing current contour lines with the map. That could be a perfect 3D image of Cheung-Pyung around before when it had been flood by making perspective images from all directions, north, south, east and west, for showing there in three dimensions. Also, flying simulation we made for close visiting can bring us to experience their real space at that time.

• 한국방사선학회논문지
• /
• 제7권4호
• /
• pp.301-305
• /
• 2013

Cone Beam CT 데이터를 3차원 컴퓨터 프로그램을 이용하여 기존의 파노라마 영상과 재구성된 파노라마 영상을 재현해서 악궁형태에 따른 치아의 왜곡을 분석하고자 하였다. Cone Beam CT의 횡단면 영상과 재구성 파노라마에서 측정된 치아의 직경은 전치부에서 구치부로 갈수록 큰 변화없이 일치되는 것을 알 수 있었다. 하지만 파노라마는 전치부에서 약간의 왜곡이 보이다가 구치부로 갈수록 왜곡이 더 심한 것을 알 수 있었다. 환자 개개인의 악궁에 맞게 재구성된 파노라마가 일반적으로 사용되는 파노라마 촬영보다 왜곡이 더 감소한다는 것을 알 수 있었다. 또한 파노라마는 전치부에서 구치부로 갈수록 왜곡이 더 심해지는 것을 알 수 있었는데, 이 또한 재구성된 파노라마 영상에서는 왜곡이 감소한다는 것을 알 수 있었다.