• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.768-772
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• 2009

This paper proposes a method for measurement three-dimensional trajectories of bubbles generated around a swimmer's arms from stereo high-speed camera videos. This method is based on two techniques: two-dimensional trajectory estimation in single-camera images and trajectory pair matching in stereo-camera images. The two-dimensional trajectory is estimated by block matching using similarity of bubble shape and probability of bubble displacement. The trajectory matching is achieved by a consistensy test using epipolar constraint in multiple frames. The experimental results in two-dimensional trajectory estimation showed the estimation accuracy of 47% solely by the general optical flow estimation, whereas 71% taking the bubble displacement into consideration. This concludes bubble displacement is an efficient aspect in this estimation. In three-dimensional trajectory estimation, bubbles were visually captured moving along the flow generated by an arm; which means an efficient material for swimmers to swim faster.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.631-632
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• 2006

The assembly of camera lens modules fur the mobile phone has not been automated so far. They are still assembled manually because of high precision of all parts and hard-to-recognize lens by vision camera. In addition, the very short life cycle of the camera phone lens requires flexible and intelligent automation. This study proposes a fast and accurate identification system of the parts by distributing the camera for 4 degree of freedom assembly robot system. Single or multi-cameras can be installed according to the part's image capture and processing mode. It has an agile structure which enables adaptation with the minimal job change. The framework is proposed and the experimental result is shown to prove the effectiveness.

• 제어로봇시스템학회논문지
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• 제11권5호
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• pp.406-410
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• 2005

A depth measurement system that consists of a single camera, a laser light source and a rotating mirror is investigated. The camera and the light source are fixed, facing the rotating mirror. The laser light is reflected by the mirror and projected to the scene objects whose locations are to be determined. The camera detects the laser light location on object surfaces through the same mirror. The scan over the area to be measured is done by mirror rotation. Advantages are 1) the image of the light stripe remains sharp while that of the background becomes blurred because of the mirror rotation and 2) the only rotating part of this system is the mirror but the mirror angle is not involved in depth computation. This minimizes the imprecision caused by a possible inaccurate angle measurement. The detail arrangement and experimental results are reported.

• Current Optics and Photonics
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• 제2권6호
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• pp.554-562
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• 2018

This study presents a color 3D scanner based on the laser structured-light imaging method that can simultaneously acquire 3D shape data and color of a target object using a single camera. The 3D data acquisition of the scanner is based on the structured-light imaging method, and the color data is obtained from a natural color image. Because both the laser image and the color image are acquired by the same camera, it is efficient to obtain the 3D data and the color data of a pixel by avoiding the complicated correspondence algorithm. In addition to the 3D data, the color data is helpful for enhancing the realism of an object model. The proposed scanner consists of two line lasers, a color camera, and a rotation table. The line lasers are deployed at either side of the camera to eliminate shadow areas of a target object. This study addresses the calibration methods for the parameters of the camera, the plane equations covered by the line lasers, and the center of the rotation table. Experimental results demonstrate the performance in terms of accurate color and 3D data acquisition in this study.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.746-751
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• 2003

A method of measuring the length of defects on the wall of the spent nuclear fuel pool using the image processing and a laser slit beam is proposed. Since the defect monitoring camera is suspended by a crane and hinged to the crane hook, the camera viewing direction can not be adjusted to the orientation that is exactly perpendicular to the wall. Thus, the image taken by the camera, which is horizontally rotated along the axis of the camera supporting beam, is distorted and thus, the precise length can not be measured. In this paper, by using the LASER slit beam generator, the horizontally rotated angle of the camera is estimated. Once the angle is obtained, the distorted image can be easily reconstructed to the image normal to the wall. The estimation algorithm adopts a 3-dimensional coordinate transformation of the image plane where both the laser slit beam and the original image of the defects exist. The estimation equation is obtained by using the information of the beam projected on the wall and the parameters of this equation are experimentally obtained. With this algorithm, the original image of the defect taken at arbitrary rotated angle can be reconstructed to an image normal to the wall. From the result of a series of experiments, the accuracy of the defect is measured within 0.6 and 1.3 % error bound of real defect size in the air and underwater, respectively under 30 degree of the inclined angle of the laser slit beam generator. Also, the error increases as the inclined angle increases upto 60 degree. Over this angle, the defect length can not be measured since the defect image disappears. The proposed algorithm enables the accurate measurement of the defect length only by using a single camera and a laser slit beam.

• 한국자동차공학회논문집
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• 제23권5호
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• pp.463-470
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• 2015

When a camera installed on a vehicle is used, estimation of the camera pose including tilt, roll, and pan angle with respect to the world coordinate system is important to associate camera coordinates with world coordinates. Previous approaches using huge calibration patterns have the disadvantage that the calibration patterns are costly to make and install. And, previous approaches exploiting multiple vanishing points detected in a single image are not suitable for automotive applications as a scene where multiple vanishing points can be captured by a front camera is hard to find in our daily environment. This paper proposes a camera pose estimation method. It collects multiple images of lane markings while changing the horizontal angle with respect to the markings. One vanishing point, the cross point of the left and right lane marking, is detected in each image, and vanishing line is estimated based on the detected vanishing points. Finally, camera pose is estimated from the vanishing line. The proposed method is based on the fact that planar motion does not change the vanishing line of the plane and the normal vector of the plane can be estimated by the vanishing line. Experiments with large and small tilt and roll angle show that the proposed method outputs accurate estimation results respectively. It is verified by checking the lane markings are up right in the bird's eye view image when the pan angle is compensated.

• 한국광학회지
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• 제24권6호
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• pp.311-317
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• 2013

작년 6월 20일, 기존의 일반 카메라에 비해 화질이 1,000배 이상인 초고분해능의 기가픽셀카메라가 미국 듀크대의 과학자들에 의해 네이처에 보고되었고 이를 월스트리트 저널이 보도했다. 보도에 따르면, 이 카메라는 미군부의 필요에 의해 공중 및 지상배치감시를 목적으로 개발되었다는 것이다. 이 기술은 향후 국방과 산업분야의 전반에 걸쳐서 기술.경제적인 파급효과가 매우 클 것으로 예상되기 때문에 국내에서도 시급히 개발에 착수할 필요가 있다고 판단된다. 이에 본 연구에서는 슈퍼 분해능을 갖는 상분할 방식의 기가픽셀 카메라를 구현하기 위한 전초작업으로써 카메라 렌즈시스템의 광학적인 구조를 고찰하였고 더불어 구조와 관련된 렌즈사양 값들의 범위를 계산해 내었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.51-54
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• 2007

The purpose of this paper is the development of measurement algorithm for green-sheet based on the digital image processing technique. The Low Temperature Cofired Ceramic (LTCC) technology can be defined as a way to produce multilayer circuits with the help of single tapes, which are used to apply conductive, dielectric and / or resistive pastes on. These single green-sheets have to be laminated together and fired in one step all. Main functionality of the green-sheet film measurement algorithm is to measure the position and size of the punching hole in each single layer. The line scan camera coupled with motorized X-Y stage is used for developing the algorithm. In order to measure the entire film area using several scanning steps, the overlapping method is used. In the process of development of the algorithm based on the image processing and analysis, strong background technology and know-how have been accumulated.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 추계학술대회
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• pp.189-192
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• 2009

이 논문은 디지털 카메라의 싱글 센서에 있는 CFA의 다양한 패턴을 비교, 분석하는데 목적을 두고 있다. 이미 널리 쓰이고 있는 패턴들이 있으나, 이미지들은 간혹 사람들이 실제로 보는 것보다 어둡게 나오거나 밝게 나오거나 또는 약간의 노이즈 현상, 불러 현상을 보여주기도 한다. 이를 개선하기 위해 아직도 많은 학자들이 패턴의 연구를 하고 있다. 이 연구는 Bayer패턴을 포함하여 7개의 패턴을 실험한다. 실험의 객관성을 위해 보간법은 선형방법으로 통일 하여 실험한다. 실험 결과는 패턴의 다양성이 이미지 향상에 크게 영향을 주지 않는다는 걸 보여주다. 그리고 패턴에 따라 그에 맞는 보간법이 필요하다는 것을 보여준다.

• 한국정보과학회논문지:시스템및이론
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• 제32권4호
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• pp.168-176
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• 2005

본 논문에서는 모델 기반으로 한 장의 사진으로부터 중점 정보를 포함한 선분을 이용하여 물체를 3차원 재구성하는 방법을 제안한다. 미리 정의된 다면체를 원시기하모델로 사용하며 한 장의 영상으로부터 복원을 시도하였다. 미리 정의된 다면체 모델을 원시기하모델로 사용하며 사용자가 원시기하모델(primitive)의 각 대응점(correspondence point)을 사진에 매핑 시키는 것으로서 3차원 재구성이 수행된다. 기존의 모델기반 3차원 재구성은 카메라 파라미터들을 복원하거나 반복(iteration)을 통한 오차최소화 기법을 사용하였다. 하지만 본 논문은 원시기하모델에 포함되어 있는 선분들과 그 선분들의 중점 정보로부터 선분을 3차원 복원하며 복원된 선분들로부터 원시기하모델을 재구성하는 방법을 제안한다. 이러한 방법은 선분을 복원하는 단계에서 요구되는 최소한의 카메라 파라미터(focal length) 만으로 원시기하모델을 재구성 할 수 있다.