• Journal of Institute of Control, Robotics and Systems
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• v.22 no.8
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• pp.579-584
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• 2016

When surgical instruments are tracked in an image-guided surgical navigation system, a stereo vision system with high accuracy is generally used, which is called optical tracker. However, this optical tracker has the disadvantage that a line-of-sight between the tracker and surgical instrument must be maintained. Therefore, to complement the disadvantage of optical tracking systems, an internal vision sensor is attached to a surgical instrument in this paper. Monitoring the target marker pattern attached on patient with this vision sensor, this surgical instrument is possible to be tracked even when the line-of-sight of the optical tracker is occluded. To verify the system's effectiveness, a series of basic experiments is carried out. Lastly, an integration experiment is conducted. The experimental results show that rotational error is bounded to max $1.32^{\circ}$ and mean $0.35^{\circ}$, and translation error is in max 1.72mm and mean 0.58mm. Finally, it is confirmed that the proposed tool tracking method using an internal vision sensor is useful and effective to overcome the occlusion problem of the optical tracker.

• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.87-90
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• 2010

최근 급속도로 보급되고 있는 스마트폰은 큰 화면과 터치 기능은 물론 GPS를 포함한 다양한 센서와 표현기능이 포함되어 있다. 이 연구에서는 대부분의 스마트폰이 제공하고 있는 풍부한 표현성능을 최대한 활용하여 작가의 의도가 독자에게 최대한 전달될 수 있는 디지털 만화 감성 뷰어와 그 저작도구에 대하여 연구하고 구현하였다. 스마트폰에 탑재된 뷰어에서 독자는 각 Cut의 장면 전환 효과, 진동, 사운드 효과 등을 통하여 효과적인 디지털 만화읽기를 할 수 있도록 하였다. 또한 이러한 기능들을 컴퓨터 비전문가인 만화저작자들이 쉽게 적용할 수 있는 저작도구를 구현하였다. 저작도구는 이러한 감성표현 기능 외에도 화면전환 효과와 씬플로우(scene-flow)도 작가의 의도대로 적용할 수 있도록 하였다. 뷰어는 Apple, Android, Windows Mobile과 Symbian 운영체제에 대해 개발하였으며, 저작도구는 Windows XP 환경에서 개발하였다. 이 연구에서 개발된 뷰어와 저작도구가 상용화되면 현재 일본제품이 독점하고 있는 국내 이동통신의 디지털 만화 시장에 적용될 것이며, 디지털 만화의 앱스토어로 발전될 수 있을 것이다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.53-54
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• 2018

최근 화력 발전소 보일러 튜브의 노후화로 인해서 불시정지 빈도수 및 재가동 시간이 늦춰지고 있다. 이는 막대한 경제적, 사회적 손실로 이어지며, 이를 예방하기 위해서는 상태기반 정비가 필요하다. 현재의 상태기반 정비는 센서, 신호 수집장치, 신호 분석단계를 거쳐 전문가가 진단하기 때문에 즉각적으로 대응하기 어려운 문제점이 있어서 설비의 재가동 시간이 늦춰지고 있다. 따라서 본 논문에서는 전문가의 도움 없이 자동으로 상태를 진단하기 위해서 머신러닝 기법 중 하나인 서포트 벡터 머신(SVM)을 이용한 진단 알고리즘을 구현하고, 이를 탑재한 진단장치를 개발하여 비전문가들도 즉각적으로 대응할 수 있게 하여 불시정지 시간과 빈도수를 줄이고자 한다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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• pp.852-862
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• 2013

This paper proposes a target tracking control method for wheeled mobile robots with nonholonomic constraints by using a backstepping-like feedback linearization. For the target tracking, we apply a vision system to mobile robots to obtain the relative posture information between the mobile robot and the target. The robots do not use the sensors to obtain the velocity information in this paper and therefore assumed the unknown velocities of both mobile robot and target. Instead, the proposed method uses only the maximum velocity information of the mobile robot and target. First, the pseudo command for the forward linear velocity and the heading direction angle are designed based on the kinematics by using the obtained image information. Then, the actual control inputs are designed to make the actual forward linear velocity and the heading direction angle follow the pseudo commands. Through simulations and experiments for the mobile robot we have confirmed that the proposed control method is able to track target even when the velocity sensors are not used at all.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2575-2577
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• 2000

We experimented on AGV driving test with color CCD camera which is setup on it. This paper can be divided into two parts. One is image processing part to measure the condition of the guideline and AGV. The other is part that obtains the reference steering angle through using the image processing parts. First, 2 dimension image information derived from vision sensor is interpreted to the 3 dimension information by the angle and position of the CCD camera. Through these processes, AGV knows the driving conditions of AGV. After then using of those information, AGV calculates the reference steering angle changed by the speed of AGV. In the case of low speed, it focuses on the left/right error values of the guide line. As increasing of the speed of AGV, it focuses on the slop of guide line. Lastly, we are to model the above descriptions as the type of PID controller and regulate the coefficient value of it the speed of AGV.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.71-78
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• 2007

There have been continuous efforts to automate welding processes. This automation process could be said to fall into two categories, weld seam tracking and weld quality evaluation. Recently, the attempts to achieve these two functions simultaneously are on the increase. For the study presented in this paper, a vision sensor is made, and using this, the 3 dimensional geometry of the bead is measured in real time. For the application in welding, which is the characteristic of nonlinear process, a fuzzy controller is designed. And with this, an adaptive control system is proposed which acquires the bead height and the coordinates of the point on the bead along the horizontal fillet joint, performs seam tracking with those data, and also at the same time, controls the bead geometry to a uniform shape. A communication system, which enables the communication with the industrial robot, is designed to control the bead geometry and to track the weld seam. Experiments are made with varied offset angles from the pre-taught weld path, and they showed the adaptive system works favorable results.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.7
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• pp.627-633
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• 2015

Accurate heading information is crucial for the navigation of intelligent vehicles. In outdoor environments, GPS is usually used for the navigation of vehicles. However, in GPS-denied environments such as dense building areas, tunnels, underground areas and indoor environments, non-GPS solutions are required. Yaw-rates from a single gyro sensor could be one of the solutions. In dealing with gyro sensors, the drift problem should be resolved. HDR (Heuristic Drift Reduction) can reduce the average heading error in straight line movement. However, it shows rather large errors in some moving environments, especially along curved lines. This paper presents a method called VDR (Vision-based Drift Reduction), a system which uses a low-cost vision sensor as compensation for HDR errors.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.840-843
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• 2019

IoT 산업이 발전하면서 기존 토이와 IoT 기술을 결합한 스마트토이가 각광 받고 있다. 스마트토이는 수동적인 방식의 기존토이와는 다르게 토이 간 인터렉션이 가능하며 전자 센서들을 사용하여 토이를 사용하는 어린아이들에 코딩을 활용한 콘텐츠를 제공가능하다. 기존 스마트토이는 처음에는 호기심을 자극하지만, 익숙해지면 흥미가 떨어지는 현상을 보인다. 이에 본 논문에서는 기존 스마트토이가 갖는 재미요소 증가와 다양한 콘텐츠의 개발을 위해서 스마트 토이에 Artificial Intelligence(AI) 기능을 접목한 AI 카메라블록을 사용하여 새로운 콘텐츠를 개발하였다.

• The Journal of Korea Robotics Society
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• v.14 no.1
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• pp.65-73
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• 2019

In this paper, we propose an algorithm that estimates the location of lunar rover using IMU and vision system instead of the dead-reckoning method using IMU and encoder, which is difficult to estimate the exact distance due to the accumulated error and slip. First, in the lunar environment, magnetic fields are not uniform, unlike the Earth, so only acceleration and gyro sensor data were used for the localization. These data were applied to extended kalman filter to estimate Roll, Pitch, Yaw Euler angles of the exploration rover. Also, the lunar module has special color which can not be seen in the lunar environment. Therefore, the lunar module were correctly recognized by applying the HSV color filter to the stereo image taken by lunar rover. Then, the distance between the exploration rover and the lunar module was estimated through SIFT feature point matching algorithm and geometry. Finally, the estimated Euler angles and distances were used to estimate the current position of the rover from the lunar module. The performance of the proposed algorithm was been compared to the conventional algorithm to show the superiority of the proposed algorithm.

• Journal of the Korea Society of Computer and Information
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• v.26 no.6
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• pp.37-46
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• 2021

In this paper, we designed and implemented a program to measure and to judge the accuracy of yoga postures using Azure Kinect. The program measures all joint positions of the user through Azure Kinect Camera and sensors. The measured values of joints are used as data to determine accuracy in two ways. The measured joint data are determined by trigonometry and Pythagoras theorem to determine the angle of the joint. In addition, the measured joint value is changed to relative position value. The calculated and obtained values are compared to the joint values and relative position values of the desired posture to determine the accuracy. Azure Kinect Camera organizes the screen so that users can check their posture and gives feedback on the user's posture accuracy to improve their posture.