• Title/Summary/Keyword: Sensor Position Location

Search Result 305, Processing Time 0.036 seconds

Active Facial Tracking for Fatigue Detection (피로 검출을 위한 능동적 얼굴 추적)

  • 박호식;정연숙;손동주;나상동;배철수
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2004.05b
    • /
    • pp.603-607
    • /
    • 2004
  • The vision-based driver fatigue detection is one of the most prospective commercial applications of facial expression recognition technology. The facial feature tracking is the primary technique issue in it. Current facial tracking technology faces three challenges: (1) detection failure of some or all of features due to a variety of lighting conditions and head motions; (2) multiple and non-rigid object tracking and (3) features occlusion when the head is in oblique angles. In this paper, we propose a new active approach. First, the active IR sensor is used to robustly detect pupils under variable lighting conditions. The detected pupils are then used to predict the head motion. Furthermore, face movement is assumed to be locally smooth so that a facial feature can be tracked with a Kalman filter. The simultaneous use of the pupil constraint and the Kalman filtering greatly increases the prediction accuracy for each feature position. Feature detection is accomplished in the Gabor space with respect to the vicinity of predicted location. Local graphs consisting of identified features are extracted and used to capture the spatial relationship among detected features. Finally, a graph-based reliability propagation is proposed to tackle the occlusion problem and verify the tracking results. The experimental results show validity of our active approach to real-life facial tracking under variable lighting conditions, head orientations, and facial expressions.

  • PDF

Accuracy Analysis of the Orbit Modeling with Various GCP Configurations and Unknown Parameter Sets (기준점 위치와 미지수 조합에 따른 궤도모델링의 정확도 분석)

  • Kim, Dong-Wook;Kim, Hyun-Suk;Kim, Tae-Jung
    • Korean Journal of Remote Sensing
    • /
    • v.24 no.2
    • /
    • pp.133-140
    • /
    • 2008
  • In this paper, we analyzed the accuracy of orbit modeling with various control point configurations and adjustment unknown parameter sets. We used 152 GCP points acquired from GPS surveying, which were distributed from Choon-chun to Nha-ju along 420km in distance. For orbit modeling, seven adjustment parameter sets were chosen to include parameters for satellite position, velocity and attitude angles at different degree of freedom. Firstly we determined the location of model point in seven configurations. Secondly we estimated model parameters for each parameter set and for each GCP configurations. Finally we applied the model to reference check points and analyzed its accuracy. We were able to find the unknown parameter set that produce best orbit modeling performance regardless of the configuration of model points.

Development of the Novel Intraoperative Neuromonitoring for Thyroid Surgery (갑상선 수술을 위한 새로운 수술 중 신경감시시스템의 개발)

  • Sung, Eui Suk;Lee, Byung Joo
    • International journal of thyroidology
    • /
    • v.11 no.2
    • /
    • pp.109-116
    • /
    • 2018
  • It is very important to identify recurrent laryngeal nerve (RLN) and prevent RLN injury during thyroid surgery. The intraoperative neuromonitoring (IONM) for the prevention of RLN injury is a useful method because it can identify the location and status of RLN and predict postoperative vocal cord function easily. The IONM consists of a stimulating side that applies electrical stimulation to the nerve and a recording side that measures the surface electromyography (EMG) of the vocal cord muscle through electrode endotracheal tube. The nerve stimulator and surgical dissector are separate instruments. So, during IONM for the prevention of the RLN injury in conventional, endoscopic, or robotic thyroid surgery, repeated exchanging between surgical instruments and the nerve stimulator is inconvenient and time consuming. On the recording side, the accuracy of the electrode endotracheal tube which measures the EMG of the vocalis muscle can be affected by contact with between electrode and vocal fold and position change of patient. We would like to introduce recent several researches to overcome the current limitations of IONM.

The Improvement of Disaster Safety Network using ICT Devices (ICT 기기를 활용한 재난안전통신망 강화 방안)

  • Hong, Sung-Hwa
    • Journal of Advanced Navigation Technology
    • /
    • v.23 no.2
    • /
    • pp.194-199
    • /
    • 2019
  • Natural disasters destroy decades of human effort and investments, thereby placing new demands on society for reconstruction and rehabilitation. In most case, the natural phenomena triggering the disasters are beyond human control. In order to solve the problems that the information resources can not be shared among disaster management sectors and their work is hard to be coordinated in city, an idea of application of ubiquitous sense network and ICT technology to model the architecture of the disaster prevention system based on the analysis of characteristics of disasters. The proposed algorithm simulated that it is possible to locate the terminal by linking the direction angle and the estimated position that can be confirmed at the time of stopping, even if the movement direction of the terminal does not move in a certain direction with only a smaller number of mobile base stations. We also confirmed that the proposed algorithms analyzed through simulation are more efficient than existing algorithms.

Study on Traveling Characteristics of Straight Automatic Steering Devices for Drivable Agricultural Machinery (승용형 농기계용 직진 자동조향장치 주행특성 연구)

  • Won, Jin-ho;Jeon, Jintack;Hong, Youngki;Yang, Changju;Kim, Kyoung-chul;Kwon, Kyung-do;Kim, Gookhwan
    • Journal of Drive and Control
    • /
    • v.19 no.4
    • /
    • pp.19-28
    • /
    • 2022
  • This paper introduces an automatic steering system for straight traveling capable of being mounted on drivable agricultural machinery which user can handle it such as a tractor, a transplant, etc. The modular automatic steering device proposed in the paper is composed of RTK GNSS, IMU, HMI, hydraulic valve, and wheel sensor. The path generation method of the automatic steering system is obtained from two location information(latitude and longitude on each point) measured by GNSS in advance. From HMI, a straight path(AB line) can be created by connecting latitude and longitude on each point and the device makes the machine able to follow the path. During traveling along the reference path, it acquires the real time position data every sample time(0.1s), compares the reference with them and calculates the lateral deviation. The values of deviation are used to control the steering angle of the machine using hydraulic valve mounted on the axle of front wheel. In this paper, Pure Pursuit algorithm is applied used in autonomous vehicles frequently. For the analysis of traveling characteristics, field tests were executed about these conditions: velocity of 2, 3, 4km/h which is applied to general agricultural work and ground surface of solid(asphalt) and weak condition(soil) such as farmland. In the case of weak ground state, two experiments were executed about no-load(without work) and load(with work such as plowing). The maximum average deviations were presented 2.44cm, 7.32cm, and 11.34cm during traveling on three ground conditions : asphalt, soil without load and with load(plowing).

A Method for Real Time Target Following of a Mobile Robot Using Heading and Distance Information (방향각 및 거리 정보에 의한 이동 로봇의 실시간 목표물 추종 방법)

  • Ko, Nak-Yong;Seo, Dong-Jin;Moon, Yong-Seon
    • Journal of the Korean Institute of Intelligent Systems
    • /
    • v.18 no.5
    • /
    • pp.624-631
    • /
    • 2008
  • This paper presents a method for a mobile robot to follow a moving object in real time. The robot follows a target object keeping the facing angle toward the target and the distance to the target to given value. The method consists of two procedures: first, the detection of target position in the robot coordinate system, and the second, the calculation of translational velocity and rotational velocity to follow the object:. To detect the target location, range sensor data is represented in histogram. Based on the real time calculation of the location of the target relative to the robot, translational velocity and rotational velocity to follow the target are calculated. The velocities make the heading angle and the distance to target converge toward the desired ones. The performance of the method is tested through simulation. In the simulation, the target moves with three different trajectories, straight line trajectory, rectangular trajectory, and circular trajectory. As shown in the results, it is inevitable to lose track temporarily of the target when the target suddenly changes its motion direction. Nevertheless, the robot speeds up to catch up and finally succeeds to follow the target as soon as possible even in this case. The proposed method can also be utilized to coordinate the motion of multiple robots to keep their formation as well as to follow a target.

Optimization of Sensor Location for Real-Time Damage assessment of Cable in the cable-Stayed Bridge (사장교 케이블의 실시간 손상평가를 위한 센서 배치의 최적화)

  • Geon-Hyeok Bang;Gwang-Hee Heo;Jae-Hoon Lee;Yu-Jae Lee
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.27 no.6
    • /
    • pp.172-181
    • /
    • 2023
  • In this study, real-time damage evaluation of cable-stayed bridges was conducted for cable damage. ICP type acceleration sensors were used for real-time damage assessment of cable-stayed bridges, and Kinetic Energy Optimization Techniques (KEOT) were used to select the optimal conditions for the location and quantity of the sensors. When a structure vibrates by an external force, KEOT measures the value of the maximum deformation energy to determine the optimal measurement position and the quantity of sensors. The damage conditions in this study were limited to cable breakage, and cable damage was caused by dividing the cable-stayed bridge into four sections. Through FE structural analysis, a virtual model similar to the actual model was created in the real-time damage evaluation method of cable. After applying random oscillation waves to the generated virtual model and model structure, cable damage to the model structure was caused. The two data were compared by defining the response output from the virtual model as a corruption-free response and the response measured from the real model as a corruption-free data. The degree of damage was evaluated by applying the data of the damaged cable-stayed bridge to the Improved Mahalanobis Distance (IMD) theory from the data of the intact cable-stayed bridge. As a result of evaluating damage with IMD theory, it was identified as a useful damage evaluation technology that can properly find damage by section in real time and apply it to real-time monitoring.

Development of Android-Based Photogrammetric Unmanned Aerial Vehicle System (안드로이드 기반 무인항공 사진측량 시스템 개발)

  • Park, Jinwoo;Shin, Dongyoon;Choi, Chuluong;Jeong, Hohyun
    • Korean Journal of Remote Sensing
    • /
    • v.31 no.3
    • /
    • pp.215-226
    • /
    • 2015
  • Normally, aero photography using UAV uses about 430 MHz bandwidth radio frequency (RF) modem and navigates and remotely controls through the connection between UAV and ground control system. When using the exhausting method, it has communication range of 1-2 km with frequent cross line and since wireless communication sends information using radio wave as a carrier, it has 10 mW of signal strength limitation which gave restraints on life my distance communication. The purpose of research is to use communication technologies such as long-term evolution (LTE) of smart camera, Bluetooth, Wi-Fi and other communication modules and cameras that can transfer data to design and develop automatic shooting system that acquires images to UAV at the necessary locations. We conclude that the android based UAV filming and communication module system can not only film images with just one smart camera but also connects UAV system and ground control system together and also able to obtain real-time 3D location information and 3D position information using UAV system, GPS, a gyroscope, an accelerometer, and magnetic measuring sensor which will allow us to use real-time position of the UAV and correction work through aerial triangulation.

Comparison of the Effect of the Interpolation Function on the Performance of the Noise Source Imaging Technology (소음원 영상화 기술의 성능에 보간 함수가 미치는 영향 비교)

  • Park, Kyu-Chil;Yoon, Jong Rak
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.20 no.2
    • /
    • pp.268-274
    • /
    • 2016
  • To find the location of a random noise source present in the three-dimensional space is required at least four microphones. Using four microphones distributed in a three-dimensional space, noise source imaging technique was applied and evaluated on their performance. To compensate resolution problem which comes from both the position of the sensor array is fixed and the sampling frequency is low, up-sampling technique and interpolation function were applied. Five different interpolation methods were applied such as zero-padding, zero-order hold, first-order hold, spline function, and random signal padding. The up-sampling rate were chosen by two, four, eight times, and counting up 16 times. As a result, it was possible to more accurately estimate the position of the noise source according to the higher of the up-sampling rate. It also found that the first-order hold and the spline function's performance were slightly falling relative to other methods.

Measuring Water Content Characteristics by Using Frequency Domain Reflectometry Sensor in Coconut Coir Substrate (FDR(Frequency Domain Reflectometry)센서를 이용한 코코넛 코이어 배지내 수분특성 측정)

  • Park, Sung Tae;Jung, Geum Hyang;Yoo, Hyung Joo;Choi, Eun-Young;Choi, Ki-Young;Lee, Yong-Beom
    • Journal of Bio-Environment Control
    • /
    • v.23 no.2
    • /
    • pp.158-166
    • /
    • 2014
  • This experiment has investigated suitable methods to improve precision water content monitoring of coconut coir substrates to control irrigation by frequency domain reflectometry(FDR) sensors. Specifically, water content changes and variations were observed at different sensing distances and positions from the irrigation dripper location, and different spaces between the FDR sensors with or without noise filters. Commercial coconut coir substrates containing different ratios of dust and chips(10:0, 7:3, 5:5, 3:7) were used. On the upper side and the side of the substrates, a FDR sensor was used at 5, 10, 20, 30cm distances respectively from the irrigation dripper point, and water content was measured by time after the irrigation. In the glass beads, sensors were installed with or without noise filtering. Closer sensing distance had a higher water content increasing rate, regardless of different coir substrate ratios. There were no differencies of water content increasing rates in 10:0 and 3:7 substrates between the upper side and the side. Whereas, 7:3 and 5:5 substrates showed higher increasing rates on the upper side measurements. Substrates with higher ratios of chip(3:7) had lower increasing rates than others. And, with noise filters, the exatitude of measurement was improved because the variation and deviation were reduced. Therefore, in coconut coir with FDR sensors, an efficient water content measurment to control irrigations can be achieved by installing sensors closer to an irrigation point and upper side of substrates with noise filters.