• 제어로봇시스템학회논문지
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• 제22권3호
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• pp.210-216
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• 2016

This paper presents a novel collision avoidance technique for mobile robots based on omni-directional vision simultaneous localization and mapping (SLAM). This method estimates the avoidance path and speed of a robot from the location of an obstacle, which can be detected using the Lucas-Kanade Optical Flow in images obtained through fish-eye cameras mounted on the robots. The conventional methods suggest avoidance paths by constructing an arbitrary force field around the obstacle found in the complete map obtained through the SLAM. Robots can also avoid obstacles by using the speed command based on the robot modeling and curved movement path of the robot. The recent research has been improved by optimizing the algorithm for the actual robot. However, research related to a robot using omni-directional vision SLAM to acquire around information at once has been comparatively less studied. The robot with the proposed algorithm avoids obstacles according to the estimated avoidance path based on the map obtained through an omni-directional vision SLAM using a fisheye image, and returns to the original path. In particular, it avoids the obstacles with various speed and direction using acceleration components based on motion information obtained by analyzing around the obstacles. The experimental results confirm the reliability of an avoidance algorithm through comparison between position obtained by the proposed algorithm and the real position collected while avoiding the obstacles.

• 한국콘텐츠학회논문지
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• 제3권1호
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• pp.71-79
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• 2003

현재까지는 해양 어류의 생태와 양식과정 등을 연구하기 위해서 연구자가 직접 육안으로 실험환경을 관찰하였으며, 양어장의 영상, 온도와 같은 상태 등의 정보를 실험실 내에서만 모니터링 할 수 있었다. 기존의 이러한 방식은 과학적이고 체계적인 방법으로 어류의 생태를 관찰할 수 없고, 많은 연구 인력이 필요하다. 따라서 본 논문에서는 리눅스를 운영체제로 사용한 임베디드 시스템을 이용하여 원격지의 실험환경 상태를 언제, 어디서든 인터넷을 통하여 실시간으로 전송 받아, 그 상태를 종합적으로 검사 및 분석할 수 있는 양어장 모니터링 시스템을 설계 및 구현한다.

• 한국지능시스템학회논문지
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• 제15권5호
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• pp.560-566
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• 2005

본 논문은 유비쿼터스 이동로봇의 자기위치인식에 적용되는 비젼시스템의 왜곡된 영상을 보정하기 위한 실용적인 방법을 제안하다. 이동로봇에서 자기위치인식은 필수적인 요소이며 카메라 비젼시스템을 이용하여 처리 가능하다. 자기위치인식에서 비젼시스템은 넓은 시야를 확보하기 위해 어안렌즈를 이용하는데, 이는 영상의 왜곡을 발생한다. 또한 이동로봇은 지속적인 움직임을 가지므로 빠른 시간 내에 영상을 처리하여 자기위치를 인식해야 한다. 따라서 이동로봇에 적용 가능한 실용적인 영상왜곡 보정기법을 제안하고 실험을 통하여 성능을 검증한다.

• 디지털융복합연구
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• 제15권12호
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• pp.543-548
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• 2017

360도 이미지는 대중에게 이전에 경험하지 못했던 특별한 시각적 경험을 제공한다. 360도 이미지를 제작할 수 있는 방법은 여러 가지가 있지만, 본 논문에서는 기존의 제작방식을 포함하여 간단하며 유효한 두 가지의 제작방법을 제시하고자 한다. 첫 번째 방법으로는 48장의 이미지를 합성하여 한 장의 360도 이미지를 만드는 것이고, 두 번째 방법으로는 6장의 이미지를 사용하여 한 장의 360도 이미지를 제작하는 것이다. 앞서 제시한 두 가지 제작 방식의 특징과 장단점의 비교를 통하여 더욱 간단하면서도 효율적인 제작방식을 선택할 수 있다. 소개를 통하여 제시되는 제작방법은 VR작품 제작의 문턱을 낮출 수 있으며, 일반인들도 360이미지 제작을 더욱 간편하게 할 수 있게 됨으로써 VR영상 콘텐츠 산업이 더욱 발전될 수 있을 것으로 기대한다.

• 제어로봇시스템학회논문지
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• 제21권8호
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• pp.766-772
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• 2015

This paper proposes an object detection method based on motion estimation using background subtraction in the fisheye images obtained through omni-directional camera mounted on the vehicle. Recently, most of the vehicles installed with rear camera as a standard option, as well as various camera systems for safety. However, differently from the conventional object detection using the image obtained from the camera, the embedded system installed in the vehicle is difficult to apply a complicated algorithm because of its inherent low processing performance. In general, the embedded system needs system-dependent algorithm because it has lower processing performance than the computer. In this paper, the location of object is estimated from the information of object's motion obtained by applying a background subtraction method which compares the previous frames with the current ones. The real-time detection performance of the proposed method for object detection is verified experimentally on embedded board by comparing the proposed algorithm with the object detection based on LKOF (Lucas-Kanade optical flow).

• 천문학회지
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• 제37권4호
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• pp.179-184
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• 2004

We have developed a wide-field imaging camera system, called WICZO, to monitor light of the night sky over extended period. Such monitoring is necessary for studying the morphology of interplanetary dust cloud and also the time and spatial variations of airglow emission. The system consists of an electric cooler a CCD camera with $60\%$ quantum efficiency at 500nm, and a fish-eye lens with $180^{\circ}$ field of view. Wide field imaging is highly desired in light of the night sky observations in general, because the zodiacal light and the airglow emission extend over the entire sky. This paper illustrates the design of WICZO, reports the result of its laboratory performance test, and presents the first night sky image, which was taken, under collaboration with Byulmaro Observatory, on top of Mt. Bongrae at Yongweol in January, 2004.

• 제어로봇시스템학회논문지
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• 제19권6호
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• pp.547-554
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• 2013

This paper proposes a novel formation algorithm of identical robots based on object tracking method using omni-directional images obtained through fisheye lenses which are mounted on the robots. Conventional formation methods of multi-robots often use stereo vision system or vision system with reflector instead of general purpose camera which has small angle of view to enlarge view angle of camera. In addition, to make up the lack of image information on the environment, robots share the information on their positions through communication. The proposed system estimates the region of robots using SURF in fisheye images that have $360^{\circ}$ of image information without merging images. The whole system controls formation of robots based on moving directions and velocities of robots which can be obtained by applying Lucas-Kanade Optical Flow Estimation for the estimated region of robots. We confirmed the reliability of the proposed formation control strategy for multi-robots through both simulation and experiment.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.601-605
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• 2009

We have proposed a measurement system for measuring a whole shape of an object easily. The proposed system consists of a camera and a cylinder whose inside is coated by a mirror layer. A target object is placed inside the cylinder and an image is captured by the camera from right above. The captured image includes sets of points that are observed from multiple viewpoints: one is observed directly, and others are observed via the mirror. Therefore, the whole shape of the object can be measured using stereo vision in a single shot. This paper shows that a prototype of the proposed system was implemented and an actual object was measured using the prototype. A method based on a pattern matching which uses a value of SSD (Sum of Squared Difference), and a method based on DP (Dynamic Programming) are employed to identify a set of corresponding points in warped captured images.

• 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.

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