• 대한한의진단학회지
• /
• 제16권3호
• /
• pp.41-48
• /
• 2012

Objectives: The aims of this study are to design a optimized mechanical structure of digital tongue imaging system (DTIS) equipped with LEDs in aspects of object distance and camera angle of coverage. Methods and Results: We tried to find optimized object distance while recording a rectangular object of common tongue size. In case object distance is 22 cm or less, edge of the rectangle was not taken beyond the shooting range. In contrast, if object distance is 40 cm or more, the rectangle image was too small. Therefore when considering the variation of subjects, we selected distance of 35-40 cm as appropriate object distance for the DTIS. We also tried to find optimized angle between camera view axis and horizontal line. We photographed from the side of the face of 7 adults with exposed tongue. We drew an exposed tongue lines to connect the tongue tip points and the tongue root points by using the photos acquired from the side faces. And then we calculated the tongue exposure angles between the vertical line and the exposed tongue lines. Mean tongue exposure angle was $28.3^{\circ}$ when tongue was lightly exposed and $13.3^{\circ}$ when maximally. So we determined $73^{\circ}$ as appropriate slope angle of part in contact with face of the DTIS and by considering that the standard variation was great, we designed control gears to adjust the slope of the camera view axis and to regulate the object distance. Conclusions: We designed a optimized mechanical structure in object distance and slope angle of part in contact with face of the DTIS.

• Journal of the Optical Society of Korea
• /
• 제17권4호
• /
• pp.336-343
• /
• 2013

Recently various types of driver assistance systems have been used for automobiles. In 2008, the U.S Congress passed a law which required that most cars be equipped with devices to warn objects behind the vehicle. Because of that, market of rear view cameras is expected to rise dramatically. Therefore many suppliers try to provide a wide angle camera for car makers. But a high distortion is caused by the wide angle might result in lower image quality. In order to improve the image quality, normally we use an algorithm to correct a distortion. Though we can improve the distorted image by correction algorithm, we must pay more cost to use it. In this paper, we propose a new optical system reducing a distortion in contrast to a conventional lens without cost. In other words, we can see only an area of interest. That is similar to reducing a field of view. Using a new optical system, we can get a less distorted image. In order to view an area of interest, we introduce an off axis optical system having refractive surfaces and reflective surfaces. In this paper, we describe the results of design and, evaluation of an off axis wide angle compact imaging system. In comparison to conventional wide angle lens, we can get the improvement of MTF, distortion, and lateral color aberrations. And we also can reduce a total cost because we don't need the outer apparatus or bracket to mount on the car.

• 대한기계학회논문집A
• /
• 제36권11호
• /
• pp.1463-1471
• /
• 2012

본 논문은 3 축 영상 장치를 기존의 2 축 경계 로봇에 적용하는 설계안을 제시하고 이러한 기동형 경계 로봇의 영상 정보를 이용한 목표 추적 알고리즘을 제안하였다. 또한 가상 시뮬레이션을 이용하여 목표 추적 알고리즘을 검증하였다. 목표추적 알고리즘에서는 카메라 영상의 중심과 카메라 영상으로 포착된 목표물 중심 사이의 위치 에러를 이용하여 영상 장치의 목표 지향 벡터를 획득하고, 역기구학을 이용하여 획득한 목표 지향 벡터를 생성해 낼 수 있는 기동형 경계 로봇의 팬, 틸트 회전 요구 각도와 카메라 영상의 안정화를 위한 롤 회전 요구각도를 계산하였다. MATLAB 과 ADAMS 를 이용하여 기동형 경계 로봇의 가상 모델을 생성하고, 가상의 목표물의 움직임에 대한 가상 모델의 운동을 확인하여 영상 기반의 목표 추적 알고리즘을 검증하였다.

• 제어로봇시스템학회논문지
• /
• 제18권2호
• /
• pp.110-117
• /
• 2012

This paper describes a new design of optical flow estimation system with three cameras. Optical flow provides useful information of camera movement; however a unique solution is not usually available for unknowns including the depth information. A camera and two tilted cameras are used to have different view of angle and direction of movement to the camera axis. Geometric analysis is performed for cases of several independent movements. The ideas of taking advantage of the extra information for robot navigation are discussed with experimental results.

• 한국콘텐츠학회논문지
• /
• 제11권4호
• /
• pp.11-17
• /
• 2011

본 논문 단일영상 내에 존재하는 피사체의 정보를 객관적인 수치로 구현하는 데 목적이 있다. 이러한 연구를 위해서 2차원의 단일영상이 가진 소실점을 기초로 하였으며, 3D 프로그램을 이용하여 단일영상을 3차원으로 재구성하였다. 또한, 3차원 재구성에 필요한 촬영카메라의 축 설정을 위해서 이미지가 가진 렌즈 화각 및 바닥 패턴을 활용하였다. 이렇게 완성된 3차원 영상은 하나의 기준이 되는 특정 피사체의 크기 값을 안다면 바닥패턴에 있는 모든 피사체의 크기 및 거리 측정이 가능하며 이를 통해 CCTV 또는 기타 범죄 사건의 영상에서 범인 및 단서가 되는 피사체의 기초정보를 획득할 수 있다.

• 보존과학회지
• /
• 제37권4호
• /
• pp.312-321
• /
• 2021

Underwater archaeology relies heavily on photography and video image recording during surveillances and excavations like ordinary archaeological studies on land. All underwater images suffer poor image quality and distortions due to poor visibility, low contrast and blur, caused by differences in refractive indices of water and air, properties of selected lenses and shapes of viewports. In the Yellow Sea (between mainland China and the Korean peninsula), the visibility underwater is far less than 1 m, typically in the range of 30 cm to 50 cm, on even a clear day, due to very high turbidity. For photographing 1 m x 1 m grids underwater, a very wide view angle (180°) fisheye lens with an 8 mm focal length is intentionally used despite unwanted severe barrel-shaped image distortion, even with a dome port camera housing. It is very difficult to map wide underwater archaeological excavation sites by combining severely distorted images. Development of practical compensation methods for distorted underwater images acquired through the fisheye lens is strongly desired. In this study, the source of image distortion in underwater photography is investigated. We have identified the source of image distortion as the mismatching, in optical axis and focal points, between dome port housing and fisheye lens. A practical image distortion compensation method, using customized image processing software, was explored and verified using archived underwater excavation images for effectiveness in underwater archaeological applications. To minimize unusable area due to severe distortion after distortion compensation, practical underwater photography guidelines are suggested.