• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1241-1241
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• 2001

We propose a new calibration method, which uses the linearization method for spectral responses and the repetitive adoptions of the linearization weight matrices to construct a frature. Weight matrices are estimated through multiple linear regression (or principal component regression or partial least squares) with forward variable selection. The proposed method is applied to three data sets. The first is FTIR spectral data set for FeO content from sinter process and the second is NIR spectra from trans-alkylation process having two constituent variables. The third is NIR spectra of crude oil with three physical property variables. To see the calibration performance, we compare the new method with the PLS. It is found that the new method gives a little better performance than the PLS and the calibration result is stable in spite of the collinearity among each selected spectral responses. Furthermore, doing the repetitive adoptions of linearization matrices in the proposed methods, uninformative variables are disregarded. That is, the new methods include the effect of variables subset selection, simultaneously.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.3-7
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• 2003

In this paper, radar scattering coefficients of earth surfaces such as grass fields, rice fields and bare soil surfaces are measured by using an auto-mounted network analyzer-based scatterometer system. The scatterometer system is calibrated both the magnitude and phase in order to obtain the accurate Mueller matrices of the earth surfaces. Then the accurate scattering matrices can be obtain from the Mueller matrices. The degree of correlation $\alpha$ is also obtained by this procedure and is used to correct AirSAR data which are not calibrated with phase variations.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.4
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• pp.418-424
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• 2017

A wheel dynamometer was installed between the rim and axle hub to measure the forces and moments applied to a vehicle. The wheel dynamometer was composed of sensing and signal processing components. Because the sensing component contained a complex structure to sense the six components of the forces and moments and the wheel rotated along with the vehicle movement, sophisticated signal processing hardware and a software algorithm were used. The strains and the calibration matrices of the wheel dynamometer along the wheel rotation angle were investigated using FEM. From the analysis, the calibration matrices were simplified using a spline interpolation. Based upon these results, the signal processing component could be effectively designed and the firmware software could be simplified.

• Proceedings of the Korean Printing Society Conference
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• 2000.12a
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• pp.0.2-0
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• 2000

Most important step for the color matching in scanner is the color coordinate transformation from the scanner RGB space to device independent uniform color space. A variety of color calibration technologies have been developed for input device. Linear or nonlinear matrices have been conveniently applied to correct the color filter\`s mismatch with color matching function in scanners. The color matching accuracy is expected to be further improved when the nonlinear matrices are optimized into subdivided smaller color spaces than in single matrix of the entire color space. This article proposed the scanner calibration method using subspace division regression analysis and it were compared with conventional method.

• Journal of the Korean Graphic Arts Communication Society
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• v.19 no.1
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• pp.4-16
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• 2001

Most important step for the color matching in scanner is the color coordinate transformation from the scanner RGB space to device independent uniform color space. A variety of color calibration technologies have been developed for input device. Linear or nonlinear matrices have been conveniently applied to correct the color filter's mismatch with color matching function in scanners. The color matching accuracy is expected to be further improved when the nonlinear matrices are optimized into subdivided smaller color spaces than in single matrix of the entire color space. This article proposed the scanner calibration method using subspace division regression analysis and it were compared with conventional method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.6
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• pp.637-645
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• 2014

This paper presents a new $4{\times}4$ multi-port amplifier(MPA) structure using reconfigurable switching matrices as input and output hybrid matrices(IHM, OHM), and phase/amplitude error calibration circuits. According to the mode selection of the switches, output power can be flexibly and effectively managed since the number of PA's to be used and the number of output port to distribute/combine amplified signals can be controlled. In addition, the proposed structure contains the phase and amplitude error calibration block that helps produce identical amplitudes and desired phase differences to the $4{\times}4$ OHM, resulting in optimizing the port-to-port isolation of the MPA system.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.3
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• pp.314-323
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• 1999

This paper introduces a methodology of active calibration of a camera pose (orientation and position) using the images of cylindrical objects that are going to be manipulated. This active calibration method is different from the passive calibration where a specific pattern needs to be located at a certain position. In the active calibration, a camera attached on the robot captures images of objects that are going to be manipulated. That is, the prespecified position and orientation data of the cylindrical object are transformed into the camera pose through the two consecutive image frames. An ellipse can be extracted from each image frame, which is defined as a circular-feature matrix. Therefore, two circular-feature matrices and motion parameters between the two ellipses are enough for the active calibration process. This active calibration scheme is very effective for the precise control of a mobile/task robot that needs to be calibrated dynamically. To verify the effectiveness of active calibration, fundamental experiments are peformed.

• The KIPS Transactions:PartB
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• v.10B no.5
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• pp.515-520
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• 2003

This paper proposes a calibration method from two images. Camera calibration is necessarily required to obtain 3D Information from 2D images. Previous works to accomplish the camera calibration needed the calibration object or required more than three images to calculate the Kruppa equation, however, we use the geometric constraints of parallelism and orthogonality can be easily presented in man-made scenes. The task of it is to obtain intrinsic and extrinsic camera parameters. The intrinsic parameters are evaluated from vanishing points and then the extrinsic parameters which are consisted of rotation matrix and translation vector of the camera are estimated from corresponding points of two views. From the calibrated parameters, we can recover the projection matrices for each view point. These projection matrices are used to recover 3D information of the scene and can be used to visualize new viewpoints.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.391-394
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• 2005

In this paper, we present an approach that is able to reconstruct 3 dimensional metric models from un-calibrated images acquired by a freely moved camera system. If nothing is known of the calibration of either camera, nor the arrangement of one camera which respect to the other, then the projective reconstruction will have projective distortion which expressed by an arbitrary projective transformation. The distortion on the reconstruction is removed from projection to metric through self-calibration. The self-calibration requires no information about the camera matrices, or information about the scene geometry. Self-calibration is the process of determining internal camera parameters directly from multiply un-calibrated images. Self-calibration avoids the onerous task of calibrating cameras which needs to use special calibration objects. The root of the method is setting a uniquely fixed conic(absolute quadric) in 3D space. And it can make possible to figure out some way from the images. Once absolute quadric is identified, the metric geometry can be computed. We compared reconstruction image from calibrated images with the result by self-calibration method.

• Analytical Science and Technology
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• v.18 no.2
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• pp.168-172
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• 2005

A comparison study of XRF and $^{31}P$-NMR method for the analysis of phosphorous in lubricating oil has been described. Pure oil and water were used for the observation of matrices effect variation by different analytical methods. Quantitative analysis was carried out by XRF and $^{31}P$-NMR using real samples. Significant difference is observed from the slopes on the calibration curves by the XRF due to the matrices (water: 124.0, oil: 276.6). While the result obtained from XRF showed a large matrix effect, the slopes obtained from $^{31}P$-NMR results of two different matrices, however, are in good agreement ranged of ${\pm}9%$ (water: 4.9, oil: 5.3).