• IEIE Transactions on Smart Processing and Computing
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• 제4권6호
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• pp.379-383
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• 2015

This paper presents an approach to detect object distance with the use of the recently developed low-cost Kinect sensor. The technique is based on Kinect color depth-image processing and can be used to design various computer-vision applications, such as object recognition, video surveillance, and autonomous path finding. The proposed technique uses keypoint feature detection in the Kinect depth image and advantages of depth pixels to directly obtain the feature distance in the depth images. This highly reduces the computational overhead and obtains the pixel distance in the Kinect captured images.

• 전기전자학회논문지
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• 제22권4호
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• pp.922-932
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• 2018

방사형 거리 센서는 측량 및 자율 주행에 널리 사용된다. 이러한 센서의 작동 원리 및 적용 방법의 교육이 필요하다. 상용 방사형 거리 센서의 저성능화를 통한 저가화가 계속되고 있지만, 교육 목적으로 사용하기에는 여전히 고가이다. 본 논문에서는 교육용 로봇에 활용할 수 있는 저가의 포토트랜지스터의 방사형 배열을 이용한 물체추적기능을 갖는 거리 센서 모듈을 제안한다. 제안하는 방법은 포토트랜지스터를 180도 범위의 배열로 배치하여 빠르게 움직이는 물체의 위치를 즉시 감지할 수 있으며 서보 모터를 사용한 센서 회전으로 감지 각도 범위를 향상하고 물체를 추적한다. 제안된 센서의 스캔 속도는 상업용 거리 센서보다 50~200배 빨라서 1ms의 제어 루프를 가지는 고성능의 교육용 모바일 로봇에 적용할 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1679-1684
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• 2004

This paper introduces a novel approach that can provide the three dimensional information on the movement of a spreader by using two CCD cameras and a laser distance sensor, which enables an ALS (Automatic Landing System) to be used for yard cranes at a harbor. So far a kind of 2D Laser scanner sensor or laser distance measuring units are used as corner detectors for the geometrical matching between the spreader and a container, which provides only 2D information which is not enough for an accurate and fast ALS system required presently. In addition to this deficiency in performance, the price for the system is too high to be adopted widely for the ALS. Therefore, to overcome these defects, a novel method to acquire the three dimensional information for the movement of a spreader including skew and sway angles is proposed using two CCD cameras and a laser distance sensor. To show the efficiency of proposed algorithm, real experiments are performed to show the accuracy improvement in distance measurement by fusing the sensory information of CCD camera and laser distance sensor.

• 센서학회지
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• 제22권6호
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• pp.387-392
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• 2013

Camera rigs for shooting 3D video are classified as manual, motorized, or fully automatic. Even in an automatic camera rig, the process of Stereoscopic 3D (S3D) video capture is very complex and time-consuming. One of the key time-consuming operations is capturing the distance parameters, which are near distance, far distance, and convergence distance. Traditionally these distances are measured by tape measure or triangular indirect measurement methods. These two methods consume a long time for every scene in shot. In our study, a compact laser distance sensing system with long range distance sensitivity is developed. The system is small enough to be installed on top of a camera and the measuring accuracy is within 2% even at a range of 50 m. The shooting time of an automatic camera rig equipped with the laser distance sensing system can be reduced significantly to less than a minute.

• 전기학회논문지
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• 제57권4호
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• pp.686-691
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• 2008

This paper proposes the concept of "virtual sensor data" and its application for real time obstacle avoidance. The virtual sensor data is virtual distance which takes care of the movement of the obstacle as well as that of the robot. In practical application, the virtual sensor data is calculated from the odometry data and the range sensor data. The virtual sensor data can be used in all the methods which use distance data for collision avoidance. Since the virtual sensor data considers the movement of the robot and the obstacle, the methods utilizing the virtual sensor data results in more smooth and safer collision-free motion.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.94.5-94
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• 2001

Unrestricted measurement method of three-dimensional walking distance utilizing body acceleration and terrestrial magnetism is discussed. The three-dimensional walking distance is derived by the integration of the three dimensional acceleration of foot during swing phase. Since the sensor system attached on the foot rotates during swing phase, the acceleration data measured on the foot include acceleration of gravity which causes inaccurate calculation of the velocity and the distance. Three gyros are used to compensate the rotation of the sensor system. Moreover, one geomagnetic sensor is employed to derive the heading direction of the subject Healthy volunteers performed ...

• 전기학회논문지
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• 제59권9호
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• pp.1692-1698
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• 2010

In this paper we use wireless sensor network and ultrasonic sensors to estimate local position of mobile robots, and to navigate it. Ultra sonic sensor is simple and accurate so it is good to use in local estimation and navigation of mobile robots. But to obtain accurate distance of two sensors they need to face each others as possible as they can. To solve this problem we rotate ultra sonic sensor which is attached to robot in 360 degrees and obtain accurate distance. We can estimate precise position of mobile robot by triangulation using obtained distance information. A mobile robot navigates using embedded encoder and compensates its coordinates by ultrasonic sensors. Results of Experiments show proposed method obtains accurate distance between sensors and coordinates of position of robot. And mobile robots can navigate designated path well.

• Journal of Biosystems Engineering
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• 제41권4호
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• pp.319-327
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• 2016

Purpose: Automated guidance systems (AGSs) for mobile farm machinery have several advantages over manual operation in the crop production industry. Many researchers and companies have tried to develop such a system. However, it is not easy to evaluate the performance of an AGS because there is no established device used to evaluate it that complies with the ISO 12188 standard. The objective of this study was to develop a tracking sensor system using five laser distance measurement sensors. Methods: One sensor-for long-range distance measurement-was used to measure travel distance and velocity. The other four sensors-for mid-range distance measurement-were used to measure lateral deviation. Stationary, manual driving, and A-B line tests were conducted, and the results were compared with the real-time kinematic differential global positioning system (RTK-DGPS) signal used by the AGS. Results: For the stationary test, the average error of the tracking sensor system was 1.99 mm, and the average error of the RTK-DGPS was 15.19 mm. For the two types of driving tests, the data trends were similar. A comparison of the changes in lateral deviation showed that the data stability of the developed tracking system was better. Conclusions: Although the tracking system was not capable of measuring long travel distances under strong sunlight illumination because of the long-range sensor's limitations, this dilemma could be overcome using a higher-performance sensor.

• Journal of Information Processing Systems
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• 제2권1호
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• pp.44-47
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• 2006

One of the critical issues in a sensor network concerns the detection of changes in data streams. Recently presented change detection schemes primarily use a sliding window model to detect changes. In such a model, a distance function is used to compare two sliding windows. Therefore, the performance of the change detection scheme is greatly influenced by the distance function. With regard to sensor nodes, however, energy consumption constitutes a critical design concern because the change detection scheme is implemented in a sensor node, which is a small battery-powered device. In this paper, we present a comparative study of various distance functions in terms of execution time, energy consumption, and detecting accuracy through simulation of speech signal data. The simulation result demonstrates that the Euclidean distance function has the highest performance while consuming a low amount of power. We believe our work is the first attempt to undertake a comparative study of distance functions in terms of execution time, energy consumption, and accuracy detection.

• 조명전기설비학회논문지
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• 제27권10호
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• pp.50-58
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• 2013

In Wireless Sensor Network, clustering scheme is used to prolong the lifetime of WSN by efficient usage of energy of sensor. In the distributed clustering protocol just like LEACH, every sensor in a network plays a cluster head role once during each epoch. So the FND is prolonged. But, even though every sensor plays a head role, the energy consumed by each sensor is different because the energy consumed increases according to the distance to the Base Station by the way of multiple increase. In this paper, we propose a mechanism to select a head depending on the distance to Base Station, which extends the timing of FND occurrence by 68% compared to the LEACH and makes network stable.