• 대기
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• 제29권5호
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• pp.537-550
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• 2019

To analyze the observation environment of solar radiation stations operated by the Korea Meteorological Administration (KMA), we analyzed the skyline, Sky View Factor (SVF), and solar radiation due to the surrounding topography and artificial structures using a Digital Elevation Model (DEM), 3D camera, and solar radiation model. Solar energy shielding of 25 km around the station was analyzed using 10 m resolution DEM data and the skyline elevation and SVF were analyzed by the surrounding environment using the image captured by the 3D camera. The solar radiation model was used to assess the contribution of the environment to solar radiation. Because the skyline elevation retrieved from the DEM is different from the actual environment, it is compared with the results obtained from the 3D camera. From the skyline and SVF calculations, it was observed that some stations were shielded by the surrounding environment at sunrise and sunset. The topographic effect of 3D camera is therefore more than 20 times higher than that of DEM throughout the year for monthly accumulated solar radiation. Due to relatively low solar radiation in winter, the solar radiation shielding is large in winter. Also, for the annual accumulated solar radiation, the difference of the global solar radiation calculated using the 3D camera was 176.70 MJ (solar radiation with 7 days; suppose daily accumulated solar radiation 26 MJ) on an average and a maximum of 439.90 MJ (solar radiation with 17.5 days).

• 한국측량학회지
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• 제38권6호
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• pp.511-519
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• 2020

카메라 캘리브레이션을 위해 일반적으로 체커보드를 이용하여 주점, 초점거리, 렌즈 왜곡을 결정한다. 체커보드는 평면 형태와 3차원 형태가 있으며 체커보드의 크기, 타겟의 배치와 타겟점의 개수에 따라 카메라 캘리브레이션 매개변수에 영향을 미친다. 본 연구에서는 스테레오 카메라 캘리브레이션을 위해 체커보드의 유형에 따른 정확도를 검사점을 이용하여 비교하였으며 이를 통해 가장 성능이 우수한 체커보드를 제안하는 것을 목적으로 하였다. 평면 형태의 크기가 큰 체커보드는 검사점과의 비교를 통해서 비교적 높은 정확도를 나타내었다. 그러나 체커보드의 크기로 인하여 이동과 회전이 불편하였고 스테레오 카메라에서 타겟점이 모두 나타날 수 있도록 촬영하는 것이 어려운 단점이 있었다. 평면 형태의 작은 크기로 제작된 체커보드는 이동 및 회전이 편리하지만 가장 낮은 3차원 정확도를 나타내었다. 높이 값이 있는 타겟을 부착한 체커보드는 타겟점의 3차원 좌표를 카메라 캘리브레이션을 위해서 관측장비를 이용하여 결정해야 하는 번거로움이 있었지만 크기가 작아 이동과 회전이 편리하였고 가장 높은 3차원 정확도를 나타내었다.

• 대한공간정보학회지
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• 제19권3호
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• pp.115-125
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• 2011

최근 이슈가 되어온 스마트폰에는 고해상도 카메라, Assisted GPS, 가속도계, 자이로스코프, 그리고 자기 계측 센서와 같이 측량에 직접 이용할 수 있는 다양한 센서들이 탑재되어 있다. 본 연구는 고해상도 영상을 제공하는 스마트폰 카메라를 검정하고 그 정확도를 평가함으로써, 사진측량에 스마트폰 영상의 활용 가능성을 제시하는데 그 목적을 둔다. 먼저, 스마트폰 카메라의 정확도 평가에 앞서 각 카메라의 렌즈 왜곡을 보정하기 위한 카메라 검정이 이루어졌고, 이 과정에서 광속조정에 의해 계산된 영상 좌표 및 대상물 좌표의 정확도를 분석하였다. 또한, 3차원 위치 결정에 있어 렌즈 왜곡 계수의 고려 유무에 따른 결과 분석이 이루어졌고, 최종적으로 측량용 카메라에 대한 스마트폰 카메라의 상대 정확도를 평가하였다. 그 결과, 스마트폰 카메라의 왜곡 보정에 있어 고차항의 방사 왜곡 계수도 고려되어야 하며, 측량용 카메라에 의한 결과와 미소한 차이를 나타내어 사진측량에 스마트폰 영상의 활용 가능성이 클 것으로 기대된다.

• 대한인간공학회지
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• 제8권2호
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• pp.35-41
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• 1989

In this paper a new method is proposed to create 3-dimensional coordinate values from two 2- dimensional images (side and front image of objects) using image processing system and two video cameras. This method is task requiring measurements of camera lense distortion, calibrations and conversin 2-dimensional images into 3-dimensional images. This system provides 3-dimensional me- asurement error of +5mm for about 2m length objects.

• 한국측량학회지
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• 제36권4호
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• pp.295-303
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• 2018

스테레오 카메라 시스템은 물리적으로 고정된 기선길이를 가지고 있어 축척이 일정하나 스테레오 영상에서 매번 특징점 매칭을 통해서 상호표정요소를 결정할 경우 축척이 고정 되어 있지 않아 실제 3차원 좌표를 측정하기 어려운 문제점이 있다. 따라서 본 연구에서는 수정된 공선조건식을 이용하여 좌우측 카메라의 내부적인 특성 및 카메라간의 관계를 동시에 결정하는 스테레오 카메라 캘리브레이션을 수행하고 이를 단일 카메라 캘리브레이션과 비교하는 것을 목적으로 하였다. 실험을 통해 근거리에 촬영한 영상에서 결정한 3차원 거리를 비교하였을 경우 단일 캘리브레이션의 결과에서는 ${\pm}0.014m$의 평균제곱근오차가 발생한 반면 스테레오 카메라의 경우에는 오차가 거의 발생하지 않았기 때문에 스테레오 카메라 캘리브레이션의 3차원 거리의 정확도가 우수하게 나타났다. 에피폴라 영상의 종시차에 대한 비교에서는 스테레오 카메라를 이용한 경우가 단일 카메라의 경우 보다 평균제곱근오차가 최대 0.3 픽셀 정도의 차이를 보였으나 그 영향은 크지 않은 것으로 나타났다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.250-255
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• 2003

The position of a 3-dimensional(3D) point can be measured by using calibrated stereo camera. To obtain more accurate measurement ,more accurate camera calibration is required. There are many existing methods to calibrate camera. The simple linear methods are usually not accurate due to nonlinear lens distortion. The nonlinear methods are accurate more than linear method, but it increase computational cost and good initial guess is needed. The multi step methods need to know some camera parameters of used camera. Recent years, these explicit model based camera calibration work with the development of more precise camera models involving correction of lens distortion. But these explicit model based camera calibration have disadvantages. So implicit camera calibration methods have been derived. One of the popular implicit camera calibration method is to use neural network. In this paper, we propose implicit stereo camera calibration method for 3D reconstruction using support vector machine. SVM can learn the relationship between 3D coordinate and image coordinate, and it shows the robust property with the presence of noise and lens distortion, results of simulation are shown in section 4.

• 제어로봇시스템학회논문지
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• 제21권7호
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• pp.634-640
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• 2015

This paper proposes a novel three-dimensional mapping algorithm in Omni-Directional Vision SLAM based on a fisheye image and laser scanner data. The performance of SLAM has been improved by various estimation methods, sensors with multiple functions, or sensor fusion. Conventional 3D SLAM approaches which mainly employed RGB-D cameras to obtain depth information are not suitable for mobile robot applications because RGB-D camera system with multiple cameras have a greater size and slow processing time for the calculation of the depth information for omni-directional images. In this paper, we used a fisheye camera installed facing downwards and a two-dimensional laser scanner separate from the camera at a constant distance. We calculated fusion points from the plane coordinates of obstacles obtained by the information of the two-dimensional laser scanner and the outline of obstacles obtained by the omni-directional image sensor that can acquire surround view at the same time. The effectiveness of the proposed method is confirmed through comparison between maps obtained using the proposed algorithm and real maps.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.763-764
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• 2013

A three-dimensional image capturing device and its signal processing algorithm and apparatus are presented. Three dimensional information is one of emerging differentiators that provides consumers with more realistic and immersive experiences in user interface, game, 3D-virtual reality, and 3D display. It has the depth information of a scene together with conventional color image so that full-information of real life that human eyes experience can be captured, recorded and reproduced. 20 Mega-Hertz-switching high speed image shutter device for 3D image capturing and its application to system prototype are presented[1,2]. For 3D image capturing, the system utilizes Time-of-Flight (TOF) principle by means of 20MHz high-speed micro-optical image modulator, so called 'optical resonator'. The high speed image modulation is obtained using the electro-optic operation of the multi-layer stacked structure having diffractive mirrors and optical resonance cavity which maximizes the magnitude of optical modulation[3,4]. The optical resonator is specially designed and fabricated realizing low resistance-capacitance cell structures having small RC-time constant. The optical shutter is positioned in front of a standard high resolution CMOS image sensor and modulates the IR image reflected from the object to capture a depth image (Figure 1). Suggested novel optical resonator enables capturing of a full HD depth image with depth accuracy of mm-scale, which is the largest depth image resolution among the-state-of-the-arts, which have been limited up to VGA. The 3D camera prototype realizes color/depth concurrent sensing optical architecture to capture 14Mp color and full HD depth images, simultaneously (Figure 2,3). The resulting high definition color/depth image and its capturing device have crucial impact on 3D business eco-system in IT industry especially as 3D image sensing means in the fields of 3D camera, gesture recognition, user interface, and 3D display. This paper presents MEMS-based optical resonator design, fabrication, 3D camera system prototype and signal processing algorithms.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.99-100
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• 2011

• 한국지형학회지
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• 제25권1호
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• pp.67-80
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• 2018

This study used aerial and terrestrial images to build a three-dimensional model of cliffs located in Pado beach using SfM (Structure from Motion) techniques. Using both images, the study purposed to reduce the shadow areas that were found when using only aerial images. Accuracy of the two campaigns was assessed by root mean square error, and monitored by M3C2 (Multiscale Model to Model Cloud Comparison) method. The result of the M3C2 in closed areas such as sea cave and notch did not express the landforms partly. However, eroded debris on sea cliffs were detected as eroded area by M3C2, as well as in captured pictures by multi-camera. The result of this study showed the applicability of multi-camera and SfM in monitoring changes of sea cliffs.