• Journal of Korea Society of Industrial Information Systems
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• v.15 no.2
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• pp.83-90
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• 2010

Sensor is a key element in various fields of applications such as sensor networks. However, they could not be easily developed because of several factors such as temperature dependence of output characteristics and/or nonlinearity. Calibration of sensor is also needed to solve these problems. Conventional calibration process required a lot of time and expenses. Therefore, it is important to develop sensor systems which can shorten development time and minimize expense. In this paper, we develop CO and $CO_2$ Sensor modules and propose a multiple sensor calibration system to resolve problems of conventional calibration process. A proposed system is composed of sensor module, system board and monitor program. Regression analysis method based on the least mean squares is used for calibration. We introduced the structure of calibration systems and experimental results. Calibration results can be used to confirm the effectiveness of the proposed system.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.577-580
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• 2004

To overcome with large size noise source distribution network design difficulty in interferometric radiometer system, especially for sub-Y-type array, a new on-board calibration technique using noise re-radiation is proposed in this paper. The suggested calibration technique is using noise re-radiation effect of center antenna after noise source injection from matched load. This approach is especially proper to sub-Y-type array interferometric synthetic aperture radiometer in mm-wave frequency band. Compared with noise injection network of a conventional synthetic aperture radiometer, the system mass, volume, and hardware complexity is reduced and cost-effective. Only one internal noise source, matched load, is used for injection using noise re-radiation technique a small set of sub-Y receiver channels is calibrated. Detailed calibration scenario is discussed and simulation results about noise re­radiation effect are presented.

• Korean Journal of Computational Design and Engineering
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• v.20 no.3
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• pp.246-253
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• 2015

In this paper, we propose calibration methods that can be applied to the markerless surgical robotic system for Intracerebral Hematoma (ICH) Surgery. This surgical robotic system does not require additional process of patient imaging but only uses CT images that are initially taken for a diagnosis purpose. Furthermore, the system applies markerless registration method other than using stereotactic frames. Thus, in overall, our system has many advantages when compared to other conventional ICH surgeries in that they are non-invasive, much less exposed to radiation exposure, and most importantly reduces a total operation time. In the paper, we specifically focus on the application of calibration methods and their verification which is one of the most critical factors that determine the accuracy of the system. We implemented three applications of calibration methods between the coordinates of robot's end-effector and the coordinates of 3D facial surface scanner, based on the hand-eye calibration method. Phantom tests were conducted to validate the feasibility and accuracy of our proposed calibration methods and the surgical robotic system.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.4
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• pp.51-57
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• 2013

Research on calibration of array antenna has become a hot spot in the area of signal processing and it is necessary to obtain the phase mismatch of each antenna channel. This paper presents a new calibration method for an array antenna system. In order to calibrate the phase mismatch of each antenna channel, we used primary synchronization signal (PSS) which exists in LTE downlink frame. Primary synchronization signal (PSS) is based on a Zadoff-Chu sequence which has a good correlation characteristic. By using correlation calculation, we can extract primary synchronization signal (PSS). After extracting primary synchronization signal (PSS), we use it to calibrate and reduce the phase errors of each antenna channel. In order to verify the new array antenna calibration algorithm which is proposed in this paper, we have simulated the proposed algorithm by using MATLAB. The array antenna system consists of two antenna elements. The phase mismatch of first antenna and second antenna is calculated accurately by proposed algorithm in the experiment test. Theory analysis and MATLAB simulation results are shown to verify the calibration algorithm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.411-414
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• 2016

K-water institute is a calibration and test institute accredited by international standard calibration center for water-level meters. Due to the absence of on-site calibration system and procedure for Float Water Level Meter, the calibration was performed only in the standard calibration laboratory. In this study, mobile calibration system and procedure were developed to calibrate Float Water Level Meter on site using scale bar and camera. It is possible to obtain reliable water-level data and achieve consistent data management.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.3
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• pp.100-109
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• 2022

In this study, calibration technology that increases the alignment accuracy in large flexible flat panels was studied. For precise of calibration, a systematization of the calibration algorithm was established, and a calibration correction technique was studied to revise calibration errors. A coordinate systems of camera and UVW stage was established to get the global position of the mark, and equations for translational and rotational calibration were systematically derived based on geometrical analysis. Correction process for the calibration data was carried, and alignment experiments were performed sequentially in cases of the presence or absence of calibration-correction. Alignment results of both calibration correction and non-calibration correction showed accuracy performance less than 1㎛. On the other hand, the standard deviation in calibration-correction is smaller than non-calibration correction. Therefore, calibration correction showed improvement of the alignment repeatability.

• Journal of information and communication convergence engineering
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• v.12 no.4
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• pp.208-214
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• 2014

In this paper, in order to solve the problems of a narrow viewing angle and the flip effect in a three-dimensional (3D) integral imaging display, we propose an improved system by using an eye tracking method based on the Kinect sensor. In the proposed method, we introduce two types of calibration processes. First process is to perform the calibration between two cameras within Kinect sensor to collect specific 3D information. Second process is to use a space calibration for the coordinate conversion between the Kinect sensor and the coordinate system of the display panel. Our calibration processes can provide the improved performance of estimation for 3D position of the observer's eyes and generate elemental images in real-time speed based on the estimated position. To show the usefulness of the proposed method, we implement an integral imaging display system using the eye tracking process based on our calibration processes and carry out the preliminary experiments by measuring the viewing angle and flipping effect for the reconstructed 3D images. The experimental results reveal that the proposed method extended the viewing angles and removed the flipping images compared with the conventional system.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.7
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• pp.621-626
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• 2015

This paper presents a camera calibration method in order to estimate the lane detection and inter-vehicle distance estimation system for an automotive safety driving system. In order to implement the lane detection and vision-based inter-vehicle distance estimation to the embedded navigations or black box systems, it is necessary to consider the computation time and algorithm complexity. The process of camera calibration estimates the horizon, the position of the car's hood and the lane width for extraction of region of interest (ROI) from input image sequences. The precision of the calibration method is very important to the lane detection and inter-vehicle distance estimation. The proposed calibration method consists of three main steps: 1) horizon area determination; 2) estimation of the car's hood area; and 3) estimation of initial lane width. Various experimental results show the effectiveness of the proposed method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.4
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• pp.290-299
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• 2019

Direction-finding equipment with multiple antennas are used to estimate the direction of a signal emitted by a source; they can be used to rescue a victim or locate a specified source. During direction finding, reflection waves are present and signal distortion is observed depending on the external shape and material of a system that incorporates the direction-finding equipment and multiple antennas. Therefore, to accurately estimate the azimuth of the signal source and develop the direction-finding equipment, a calibration should be performed to reflect the influence of the antenna arrangement(layout) and system contour. In this paper, we describe an in-flight calibration method to develop direction-finding equipment to locate communication signals using an aviation system, and we analyze the direction-finding performance when applying phase calibration data obtained through the in-flight calibration.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.141-146
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• 2005

Flow meters in partly filled pipes are set up and run in Korea now days, but there are no standard calibration procedures for the flow meters in accordance with ISO/IEC 17025, the standard calibration procedure based on the standard calibration procedures for flow meter in closed conduits and the technical notes of flow meter's makers is developed. the measurement uncertainty of the calibration for the flow meter in partly filled pipes is evaluated.