http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Vision-based markerless measurement system for relative vessel positioning
Mizuchi, Yoshiaki,Ogura, Tadashi,Kim, Youngbok,Hagiwara, Yoshinobu,Choi, Yongwoon IET 2016 IET science, measurement & technology Vol.10 No.6
<P>The measurement of relative vessel positioning is important to prevent the risk of vessel collision or the deterioration of working efficiency. This study presents a vision-based system for measuring the relative position and heading between a vessel and a target object without the installation of transponders, reflectors, or markers. Such a markerless measurement system, which is not restricted by the presence or the absence of transponders, is a method of expanding feasible conditions for relative vessel positioning. The proposed system consists of multiple camera units that can measure the distance and direction between an initially designated point on a target object while keep track of the designated point. To evaluate the measurement performance for the proposed system, the authors conducted measurements by using a prototype system in water. The results demonstrated that the system can keep track of the designated points and accurately measure the position and heading of a vessel relative to a target object, despite the vessel's roll motion.</P>
Monocular 3D Palm Posture Estimation Based on Feature-Points Robust against Finger Motion
Yoshiaki Mizuchi,Yoshinobu Hagiwara,Akimasa Suzuki,Hiroki Imamura,Yongwoon Choi 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10
The usability of wearable augmented reality (AR) systems would improve by letting users arbitrarily display virtual information on their palm and simultaneously manipulate it as tablet computers or smartphones. To realize such interaction between users and virtual information, we aim to robustly estimate 3-D palm posture against finger motion. This is based on the assumption that finger motion is separately estimated from palm posture and applied to manipulation of displayed information. In addition, the capability of electric sources, sensors, and processors are very limited in wearable computers. For this reason, by using a monocular camera and estimating palm posture from only a few image feature-points, we achieve an efficient estimation that satisfies real-time constraint on wearable computers. The accuracy and the robustness of our method are demonstrated by qualitative and quantitative comparison with a widely-used cardboard maker. Additionally, we confirmed that our method is run on a mobile computer at the average of 12.44 msec per frame.
Estimation for a Hand Position and Orientation Robust to Motion of Fingers Using a Web Camera
Y. Mizuchi,H. Kawai,Y. Hagiwara,H. Imamura,Y. Choi 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10
We present a method to estimate the position and the orientation of a hand from a captured image for applications which need to manipulate instinctively and freely using a hand. We use a hand as a tool instead of an input device such as a mouse or a marker, and we use only a web camera instead of multiple-camera or an infrared camera, in order to improve mobility and usability. We focused on four valley-points between neighboring fingers as invariant feature points. By detecting four valley-points, the method makes possible the robust estimation for the position and the orientation of a hand regardless of the bending and the closing of fingers. In the method, we are able to move fingers freely when all valley-points are viewable. In an experiment, we qualitatively evaluated the robustness and usefulness of the proposed method by drawing 3DCG objects.
Yoshiaki Mizuchi,Tadashi Ogura,Young-Bok Kim,Yoshinobu Hagiwara,Yongwoon Choi 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10
In this study, we propose a measurement system consists of two pairs of multiple cameras mounted on a pan-tilt unit and a landmark installed on a target side. The purpose of the proposed system is to measure relative position and heading angle of a vessel to a target at a close distance, in order to reduce collision risks by automation of vessel positioning that requires high measurement accuracy and rate. To achieve such measurement, cameras that have wide sensing range and high angular resolution are used instead of GPS, radars, or laser sensors. The proposed system also has the ability of accurate and fast measurement of the distance and direction angle to a target by applying a simple and robust target detection method. The position and heading of a vessel are determined from two pairs of the distance and direction angle. To evaluate the measurement accuracy of the proposed system, we measured position and heading of the system relative to landmarks on several conditions including positional displacement and rotation. The experimental results demonstrate that the proposed system can be used for automation of vessel positioning at a close distance.
Distance Measurement System using Stereo Camera for Automatic Ship Control
Tadashi Ogura,Yoshiaki Mizuchi,Yoshinobu Hagiwara,Youngbok Kim,Akimasa Suzuki,Yongwoon Choi,Kazuhiro Watanabe 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10
A long distance measurement system using a stereo camera mounted on a rotation control device is proposed for automatic ship control, and the performance of the system is presented to verify the usefulness of it. As a solution to prevent ship operators from maritime accidents owing to their strain for a long period, the distance measurement system is often required to automatically control the posture or berthing of a ship. Here, we discuss the system structure suitable for used environment and its experimental results. From the experiment conducted to imagine the distance measurement necessary to altering the posture and translational motion between a ship and its facilities, the average error for the range of 20 to 100 m was less than 1 percent.
Highly Accurate Stereo-based Measuring and Tracking System for Vessel Control
Tadashi Ogura,Yoshiaki Mizuchi,Young-Bok Kim,Yongwoon Choi 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10
This paper describes the highly accurate stereo-based measuring and tracking system that measures the distance to a specific landmark installed on a target side. Our goal is to obtain the accurate distance from a vessel to a target such as a wharf for precise vessel control. In order to achieve this, the system should have high distance measurement accuracy and the robustness against waving motion on a vessel. In this study, high accurate distance measurement is achieved by improved target detection that has sub-pixel positional accuracy. The robustness of the measurement against the motion is also achieved by synchronizing the capture timing of the stereo cameras. The effectiveness of the sub-pixel estimation is demonstrated by comparing the measurement results with or without the improved target detection. Another result of the measurement from 5 to 20 m distance demonstrates that the system has 10 mm accuracy. We also conducted the swing experiment to verify the robustness of the system against waving motion. Then, the system robustly measures the distance within 5 mm errors on 20 degrees per second and 5 Hz swing.