• Journal of Welding and Joining
• /
• 제19권2호
• /
• pp.200-207
• /
• 2001

Three-diemnsional bead profile was measured using the biprism stereo vision sensor in GMAW, which consists of an optical filter, biprism and CCD camera. Since single CCD camera is used, this system has various advantages over the conventional stereo vision system using two cameras such as finding the corresponding points along the horizontal scanline. In this wort, the biprism stereo vision sensor was designed for the GMAW, and the linear calibration method was proposed to determine the prism and camera parameters. Image processing techniques were employed to find the corresponding point along the pool boundary. The ism-intensity contour corresponding to the pool boundary was found in the pixel order and the filter-based matching algorithm was used to refine the corresponding points in the subpixel order. Predicted bead dimensions were in broad agreements with the measured results under the conditions of spray mode and humping bead.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제9권9호
• /
• pp.3721-3737
• /
• 2015

3D reconstruction based on binocular data is significant to machine vision. In our method, we propose a new and high efficiency 3D reconstruction approach by using a consumer camera aiming to: 1) address the configuration problem of dual camera in the binocular reconstruction system; 2) address stereo matching can hardly be done well problem in both time computing and precision. The kernel feature is firstly proposed in calibration stage to rectify the epipolar. Then, we segment the objects in the camera into background and foreground, for which system obtains the disparity by different method: local window matching and kernel feature-based matching. Extensive experiments demonstrate our proposed algorithm represents accurate 3D model.

• 한국전산구조공학회논문집
• /
• 제31권4호
• /
• pp.207-213
• /
• 2018

본 연구에서는 건물 실내 공간 정보 획득을 위해 Microsoft사의 $Kinect^{(R)}$ v2를 활용한 point cloud 기법을 도입하였다. 카메라로 취득한 2차원의 투영 공간 이미지 픽셀 좌표를 각 카메라의 보정을 거쳐 3차원 이미지 변환하며 이를 토대로 공간 정보를 구현하였다. 기준점을 중심으로 $360^{\circ}$ 회전하여 취득한 3차원 이미지를 통해 거리 측정이 불가한 기존의 2차원 이미지의 한계를 개선하였으며, 이 과정을 통해 얻은 point cloud를 통해 3차원 map을 형성하였다. 형성된 3차원 map은 기존의 공간정보 융 복합을 위한 센서와 비슷한 수준의 측정 효율을 가지면서 동시에 렌즈 왜곡 현상에 대한 후처리 과정을 통해 공간 정보를 정확하게 측정할 수 있도록 하였다. 측정한 결과를 2D 도면과 실제 공간 및 구조부재의 길이 및 위치 등과 비교하여 검증하였다.

• 한국컴퓨터그래픽스학회논문지
• /
• 제9권3호
• /
• pp.15-21
• /
• 2003

An algorithm is developed for augmenting a real video with virtual graphics objects without computing Euclidean information. Real motion of the camera is obtained in affine space by a direct linear method using image matches. Then, virtual camera is provided by determining the locations of four basis points in two input images as initialization process. The four pairs of 2D location and its 3D affine coordinates provide Euclidean orthographic projection camera through the whole video sequence. Our method has the capability of generating views of objects shaded by virtual light sources, because we can make use of all the functions of the graphics library written on the basis of Euclidean geometry. Our novel formulation and experimental results with real video sequences are presented.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.1255-1258
• /
• 2008

Roll to roll (R2R) system, known as 'web processing', is the process of producing these electronic devices on a roll of flexible plastic. With the need of improved performance and productivity in R2R industry, effective control and on-line supervision for web quality is essential. In this report, we present a system for on-line measurement of wrinkles, one of defects incurring due to compressive stresses developed in the web. This system is able to capture an image generated when a well defined line shape laser beam passes through a transparent web. The system calculates 3D shape information, including the height of the wrinkle on the web, and displays the images for the shape information of the web in real time. By using area scan camera and machine vision laser, this system takes more advantages of setting up as a simple and low cost system compared to the line scan camera systems that widely used in web manufacturing. Specific calibration method and analysis on the achievable accuracy will be discussed.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
• /
• pp.504-507
• /
• 2007

The KOMPSAT-2 satellite is a push-broom system with MSC (Multi Spectral Camera) which contains a panchromatic band and four multi-spectral bands covering the spectral range from 450nm to 900nm. The PAN band is composed of six CCD array with 2528 pixels. And the MS band has one CCD array with 3792 pixels. Raw imagery generated from a push-broom sensor contains vertical streaks caused by variability in detector response, variability in lens falloff, pixel area, output amplifiers and especially electrical gain and offset. Relative radiometric calibration is necessary to account for the detector-to-detector non-uniformity in this raw imagery. Non-uniformity correction (NUC) is that the process of performing on-board relative correction of gain and offset for each pixel to improve data compressibility and to reduce banding and streaking from aggregation or re-sampling in the imagery. A relative gain and offset are calculated for each detector using scenes from uniform target area such as a large desert, forest, sea. In the NUC of KOMPSAT-2, The NUC table for each pixel are divided as HF NUC (high frequency NUC) and LF NUC (low frequency NUC) to apply to few restricted facts in the operating system ofKOMPSAT-2. This work presents the algorithm and process of NUC table generation and shows the imagery to compare with and without calibration.

• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2009년도 IWAIT
• /
• pp.659-663
• /
• 2009

In this paper, we propose a rectification method that can convert ray space data obtained by controlled camera array to ideal data. Here, Ideal data is obtained by getting longitudinal and transversal epipolar line between cameras vertical and horizontal. However it is actually difficult to arrange cameras strictly because we arrange cameras by hand. As conventional method, we have use camera-calibration method. But if we use this method there are some errors on the output image. When we generate arbitrary viewpoint images this error is critical problem. We focus attention on ideal trajectory of characteristic point. And to minimize the error directly we parallelize the real one. And we showed usefulness of proposed technique. Then using the proposed technique, we were successful reducing the error to less than 0.5 pixels.

• 융합신호처리학회논문지
• /
• 제7권3호
• /
• pp.108-115
• /
• 2006

본 논문에서는 주행하는 차선 내에 존재하는 선행차량의 위치측정 및 차량까지의 거리를 정확히 인식하기 위해 차량의 요동에 기인되는 피칭오차를 보정하여 계측하는 알고리듬을 제안하였다. 선행 차량까지의 거리를 정확히 계측하기 위하여 2 차원 영상좌표로부터 사영기하학을 적용하여 3 차원 좌표를 얻을 수 있는 카메라 Calibration 알고리듬을 확립하고, View Frustum(V.F.) 모델을 이용하여 직선부분에 대한 도로의 영상 모델을 제시하였다. 기 발표된 많은 연구논문들은 도로가 평면이라 가정하여 도로와 차량사이의 기하적인 변화에 따른 오차 특성을 고려하지 않은 경우가 많다. 이를 보완하고자 본 논문에서는 카메라 Calibration 알고리듬을 적용하여 실세계 좌표계와 영상좌표 계 사이의 기하해석으로 사영행렬을 추출하였고, V.F. 모델을 이용하여 소실점의 기하적인 해석을 통하여 차량의 피칭변화 에 따른 오차특성을 보정하였다. 실험결과 거리의 오차를 현저하게 줄일 수 있어 피칭변화에 강인함을 확인할 수 있었다.

• 방송공학회논문지
• /
• 제25권7호
• /
• pp.1095-1106
• /
• 2020

In this paper, we propose an algorithm that extracts a high-precision 3D skeleton using a model generated using a distributed RGB-D camera. When information about a 3D model is extracted through a distributed RGB-D camera, if the information of the 3D model is used, a skeleton with higher precision can be obtained. In this paper, in order to improve the precision of the 2D skeleton, we find the conditions to obtain the 2D skeleton well using the PCA. Through this, high-quality 2D skeletons are obtained, and high-precision 3D skeletons are extracted by combining the information of the 2D skeletons. Even though this process goes through, the generated skeleton may have errors, so we propose an algorithm that removes these errors by using the information of the 3D model. We were able to extract very high accuracy skeletons using the proposed method.

• 한국정보전자통신기술학회논문지
• /
• 제12권6호
• /
• pp.537-546
• /
• 2019

본 논문에서는 휴대하기 편하고 3D 콘텐츠 제작이 용이한 트윈 카메라 모듈 시스템을 구현하고자 하였다. 제안한 트윈 카메라 모듈 시스템은 2D 스테레오 카메라로 부터 입력되는 영상을 변환하여 3차원 영상으로 출력할 수 있는 시스템이다. 본 눈문에서 제안한 시스템의 성능평가를 위해 Test Platform을 이용하여 좌, 우 두 개의 렌즈로 촬영된 스테레오 입체 영상의 좌, 우 영상 간의 시차에 따른 회전(Rotation), 기울기(Tilt)에 대한 보정을 평가하였다. 또한 SIFT(Scale Invariant Feature Transform) 알고리즘을 이용하여 3D 입체 영상의 거리오차(Depth Error)를 검증하여 트윈 카메라 모듈 시스템의 효율성을 검증하고자 하였다. 본 논문에서 제안한 트윈 카메라 모듈 시스템은 촬영된 영상을 3D 입체 영상과 준비 영상으로 변화하여 외부에 출력하면 각기 다른 3D 입체 영상 제작 방식에 따른 출력장치에 맞춰 디스플레이가 가능하다. 또한 생성된 영상을 준비 영상과 입체 영상을 각기 다른 채널을 통해 출력하여 많은 제품에 적용하기 쉽고 간편하게 3D 입체 영상 콘텐츠를 제작하는데 이용할 수 있을 거라 기대한다.