• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.179-183
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• 2002

This paper presents a new approach to the calibration of a SCARA robot orientation with a camera modeling that accounts for major sources of camera distortion, namely, radial, decentering, and thin prism distortion. radial distortion causes an inward or outward displacement of a given Image point from its ideal location. Actual optical systems are subject to various degrees of decentering, that is, the optical centers of lens elements are not strictly collinear. Thin prism distortion arises from imperfection in lens design and manufacturing as well as camera assembly It is our purpose to develop the vision system for the pattern recognition and the automatic test of parts and to apply the line of manufacturing.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.225-229
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• 1997

This paper describes the camera calibration based-neural network with a camera modeling that accounts for major sources of camera distortion, namely, radial, decentering, and thin prism distortion. Radial distortion causes and inward or outward displacement of a given image point from its ideal location. Actual optical systems are subject to various degrees of decentering, that is, the optical centers of lens elements are not strictly collinear. Thin prism distortion arises from imperfection in lens design and manufacturing as well as camera assembly. It is our purpose to develop the vision system for the pattern recognition and the automatic test of parts and to apply the line of manufacturing. The performance of proposed camera calibration is illustrated by simulation and experiment.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.65-69
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• 1997

This paper presents a new approach to the calibration of a SCARA robot orientation with a camera modeling that accounts for major sources of camera distortion, namely, radial, decentering, and thin prism distortion. Radial distortion causes an inward or outward displacement of a given image point from its ideal location. Actual optical systems are subject to various degrees of decentering, that is, the optical centers of lens elements are not strictly collinear. Thin prism distortion arises from imperfection in lens design and manufacturing as well as camera assembly. It is our purpose to develop the vision system for the pattern recognition and the automatic test of parts and to apply the line of manufacturing.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.117-121
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• 2001

This paper presents a new approach to the calibration of a SCARA robot orientation with a camera modeling that accounts for major sources of camera distortion, namely, radial, decentering, and thin prism distortion. Radial distortion causes an inward or outward displacement of a given image point from its ideal location. Actual optical systems are subject to various degrees of decentering, that is, the optical centers of lens elements are not strictly collinear. Thin prism distortion arises from imperfection in lens design and manufacturing as well as camera assembly. It is our purpose to develop the vision system for the pattern recognition and the automatic test of parts and to apply the line of manufacturing.

• Journal of the Optical Society of Korea
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• v.3 no.2
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• pp.80-85
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• 1999

We propose and demonstrate a new scheme for suppression of output distortion in an open-loop gyroscope employing an erbium-doped fiber amplifier/source (FAS). In addition to the main modulation for the rotation rate measurement, a small auxiliary modulation at a different frequency is used to extract an error signal, which is necessary for keeping the quasi-dc component of the feedback signal power at a constant level for varying rotation rate. By active tracking of the optimum modulation condition using this two-frequency modulation scheme, we obtain stable gyro output with suppressed distortion as well as stable FAS characteristics. We also calculate the distortion in the gyro response due to the feedback effect, from which we estimate the FAS gyro output distortion due to the residual ac feedback effect when the dc feedback effect is removed by the proposed scheme. The measured residual deviation agrees reasonably with the estimation.

• Current Optics and Photonics
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• v.3 no.3
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• pp.236-242
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• 2019

An Nd:YAG slab structure was designed for a high-power zigzag slab laser amplifier based on computational simulation of the wavefront distortion. For the simulation, the temperature distribution in the slab was calculated at first by thermal analysis. Then, the optical path length (OPL) was obtained by a ray tracing method for the corresponding refractive index variation inside the slab. After that, the OPL distribution of the double-pass amplified beam was calculated by summing the results obtained for the first and second passes. The amount of wavefront distortion was finally obtained as the peak-to-valley value of the OPL distribution. As a result of this study, the length and position of the gain medium were optimized by minimizing the transverse wavefront distortion. Under the optimized conditions, the transverse wavefront distortion of the double-pass amplified beam was less than $0.2{\mu}m$ for pump power of 14 kW.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.10
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• pp.41-49
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• 2004

Nonlinear distortion introduced by the optical transmitter using a direct modulation of laser diode(LD) and an indirect modulation of optical modulator can limit considerably the performance of analog optical link system such as subcarrier multiplexing system. In this paper, we have compensated the nonlinear distortion of LD and optical modulator using electrical predistorter. In the case of LD, two-tone experiments using 877.5 MHz and 882.5 MHz have shown reduction of 19 dB in third-order intermodulation product(IMP$_3$). And in the case of optical modulator, we have achieved nearly 21 dB reduction in IMP3 through two-tone experiments using 1.8975 GHz and 1.9025 GHz. The spurious free dynamic ranges of LD and optical modulator are also improved by 5 dB/Hz$^{2}$ 3/ and 7 dB/Hz$^{2}$ 3/, respectively.

• Journal of electromagnetic engineering and science
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• v.3 no.2
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• pp.79-85
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• 2003

In this paper, we investigated the degree of compensation for distorted optical pulse of wavelength division multiplexed(WDM) channel with initial frequency chirp generated in optical transmitter. The WDM channel signal distortion is due to chromatic dispersion, self phase modulation(SPM) and cross phase modulation(XPM) in fiber. The considered system is 3 ${\times}$ 40 Gbps intensity modulation direct detection(IM/DD) WDM transmission systems, which adopted mid-span spectral inversion(MSSI) as compensation method. We confirmed that the effect of initial frequency chirp on compensation for signal distortion due to a SPM is gradually decreased as a dispersion coefficient of fiber becomes gradually small. But, in the aspect of a compensation for signal distortion due to both SPM and XPM, the effect of initial frequency chirp on compensation is gradually decreased as a dispersion coefficient of fiber becomes gradually large.

• Journal of information and communication convergence engineering
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• v.17 no.4
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• pp.227-233
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• 2019

In long-haul optical communication system consisting of standard single-mode fiber spans and fiber amplifiers, such as the erbium-doped fiber amplifier, performance is deteriorated by signal distortion due to chromatic dispersion and nonlinearity of the fiber. A combination of dispersion management and optical phase conjugation is an effective technique to compensate for the distortion. In an optical link configured by this combination, a dispersion map mainly affects the compensation of the distorted optical signals. This paper proposes new dispersion maps configured by the decaying or expanding distribution of residual dispersion per span (RDPS) in a dispersion-managed link combined with a midway optical phase conjugator. The effect of the proposed dispersion maps on the compensation for distorted 24 channel × 40 Gbps wavelength-division multiplexed signals was assessed through numerical simulation. It was confirmed that all the proposed dispersion maps are most appropriate for the compensation and, furthermore, for the flexibility of link configuration than conventional links.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1617-1620
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• 1997

This paper describes the camera caliberation based-neural network with a camera modeling that accounts for major sources of camera distortion, namely, radial, decentering, and thin prism distortion. Radial distoriton causes an inward or outward displacement of a given image point from its ideal location. Actual optical systems are subject to various degrees of decentering, that is the optical centers of lens elements are not strictly collinear. Thin prism distortion arises from imperfection in lens design and manufacturing as well as camera assembly. It is our purpose to develop the vision system for the pattern recognition and the automatic test of parts and to apply the line of manufacturing. The performance of proposed camera aclibration is illustrated by simulation and experiment.