• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2333-2335
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• 1998

Recently, the development of computer achieves a system which is similar to the mechanics of human visual system. The 3D measurement using monocular vision system must be achieved a camera calibration. So far, the camera calibration technique required reference target in a scene. But, these methods are inefficient because they have many calculation procedures and difficulties in analysis. Therefore, this paper proposes a native method that without reference target in a scene. We use the grid type frame with different line widths. This method uses vanishing point concept that possess a rotation parameter of the camera and perspective ration that perfect each line widths into a image. We confirmed accuracy of calibration parameter estimation through experiment on the algorithm with a grid paper with different line widths.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.199-204
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• 1999

The robot inverse calibration method using a neural networks is proposed in this paper. A high-order networks has been used in this study. The Pi-Sigma networks uses linear summing units in the hidden layer and product unit in output layer. The inverse calibration model which compensates the difference of joint variables only between measuring value and analytic value about the desired pose(position orientation) of a robot is proposed. The compensated values are determined by using the weights obtained from the learning process of the neural networks previously. To prove the reasonableness, the selected compliance automatic robot arm type direct drive robot and anthropomorphic robot are simulated. It shows that the proposed calibration method can reduce the errors of the joint variables from ${\pm}$0.15$^{\circ}$to ${\pm}$0.12$^{\circ}$.

• YAKHAK HOEJI
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• v.48 no.1
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• pp.60-64
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• 2004

Near-infrared (NIR) spectroscopy was used to determine rapidly and nondestructively the content of ambroxol in intact ambroxol tablets containing 30 mg (12.5％ m/m nominal concentration) by collecting NIR spectra in range 1100-1750 nm. The laboratory-made samples had 10.3∼15.9％ m/m nominal ambroxol concentration. The measurements were made by reflection using a fiber-optic probe and calibration was carried out by partial least square regression (PLSR) with autoscaling. Model validation was performed by randomly splitting the data set into calibration and validation data set (7 samples as a calibration data set and 5 samples as a validation data set). The developed NIR method gave results comparable to the known values of tablets in a laboratorial manufacturing Process, standard error of calibration (SEC) and standard error of prediction (SEP) being 0.49％ and 0.49％ m/m respectively. The method showed good accuracy and repeatability NIR spectroscopic determination in intact tablets allowed the potential use of real time monitoring for a running production process.

• ETRI Journal
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• v.35 no.4
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• pp.718-721
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• 2013

This letter proposes a novel calibration method for a multiport amplifier (MPA) to achieve optimum port-to-port isolation by correcting both the amplitude and phase of the calibration signals. The proposed architecture allows for the detection of the phase error and amplitude error in each RF signal path simultaneously and can enhance the calibrated resolution by controlling the analog phase shifters and attenuators. The designed $2{\times}2$ and $4{\times}4$ MPAs show isolation characteristics of 30 dB and 27 dB over a frequency range of 19.5 GHz to 22.5 GHz, respectively.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.4
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• pp.161-167
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• 2001

Camera calibration is very important problem in 3D measurement using vision system. In this paper is proposed the simple method for camera calibration. It is designed that uses the principle of vanishing points and the concept of corresponding points extracted from the parallel line pairs. Conventional methods are necessary for 4 reference points in one frame. But we proposed has need for only 2 reference points to estimate vanishing points. It has to calculate camera parameters, focal length, camera attitude and position. Our experiment shows the validity and the usability from the result that absolute error of attitude and position is in $10^{-2}$.

• The Korean Journal of Applied Statistics
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• v.6 no.2
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• pp.227-235
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• 1993

Calibration relates the estimation of independent variable which rquires more effort or expense than dependent variable does. It would be provided with high accuracy because a little change of the result of independent variable cn cause a serious effect to the human being. Usual statistical analysis assumes the normality of error distribution or linearity of data. It is desirable to analyze the data without those assumptions for the accuracy of the calibration. In this paper, we calibrated the data nonparametrically without those assumptions and derived confidence interval estimate for the independent variable. As a method, we used kernel method which is popular in modern statistical branch. We derived bootstrap confidence interval estimate from the bootstrap confidence band.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.4
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• pp.859-865
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• 1999

Many sensors such as a laser, and CCD camera to obtain 3D information have been used, but most of algorithms for laser calibration are inefficient since a huge memory and experiment data are required. This method saves a memory and an experimental data since the 3D information are obtained simply triangulation method. In this paper, the calibration algorithm of a slit km laser based on triangulation method is introduced to calculate 3D information in the real world. The laser beam orthogonally mounted on the XY table is projected on the floor. A CCD camera observes the intersection plane of a light and an object plane. The 3D information is calculated using observed and calibration data.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.7
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• pp.629-634
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• 2008

This paper presents the flight test procedure and the results for the airspeed indicator calibration of a light airplane the name of ChangGong-91, which is the first type certified aircraft from Korean Ministry of Construction and Transportation, as a part of the flight test validation to get the certification. The flight tests for airspeed position error calibrations are conducted using tower fly by method in order to calibrate swivel head testboom which is attached to the right wing tip of the airplane. Also system to system method is applied in order to calibrate the airspeed indicator of the cockpit. The flight test is conducted at the basis of the 'Korean Airworthiness Standard' which is the regulation of Korean Ministry of Construction and Transportation. The airspeed error range for the testboom and the airspeed indicator are determined to $-0.75{\sim}+0.75$ knot and to $-4.0{\sim}+2.0$ knots, respectively. The calibration results are applied to ChangGong-91 Flight Operation Manual.

• Journal of the Korea Society of Computer and Information
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• v.3 no.3
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• pp.7-15
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• 1998

In this paper a calibration method is proposed for calibrating distorted image from lens and various factors. The similar origin image can be generated by the proposed method that calculate a calibration coefficient by modeling third transformation between standard image and distorted image and then apply the coefficient to distorted image The coefficient is effective until camera position is changed or lens is exchanged. This research consists of processes to calculate calibration coefficient and to set similar real image by the coefficient. Proposed method especially is applied to a system to obtain a real image from a distorted image causing effects of special system environment and camera lens The advantage of this method is verified by experiment using distorted images from a CCD camera that will attach atomic pile.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.6_2
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• pp.593-605
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• 2012

LiDAR systems provide dense and accurate topographic information. A pre-requisite to achieving the potential accuracy of LiDAR is having a proper system calibration, which aims at estimating all the systematic errors in the system measurements and the mounting parameters relating the different components. This paper presents a rigorous and two approximate methods for LiDAR system calibration. The rigorous approach makes use of the LiDAR equation and the system raw measurements. The approximate approaches utilize simplified LiDAR equations using some assumptions, which allow for less strict requirements regarding the raw measurements. The first presented approximate method, denoted as quasi-rigorous, assumes that we are dealing with a vertical platform (i.e., small pitch and roll angles). This method requires time-tagged point cloud and trajectory position data. The second approximate method, denoted as simplified, assumes that we are dealing with parallel strips, vertical platform, and minor terrain elevation variations compared to the flying height above ground. Such method can be performed using the LiDAR point cloud only. Experimental results using a real dataset, whose characteristics deviate to some extent from the utilized assumptions in the approximate methods, are presented to provide a comparative analysis of the outcome from the introduced methods.