• Title/Summary/Keyword: optical distortion

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Development of camera caliberation technique using neural-network (신경회로망을 이용함 카메라 보정기법 개발)

  • 한성현;왕한홍;장영희
    • 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.

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Correction Method for Geometric Image Distortion and Its Application to PCB Inspection Systems (인쇄회로기판 검사를 위한 기하학적 영상 왜곡의 보정 방법)

  • Lee, Wan-Young;Park, Tae-Hyoung
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.8
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    • pp.772-777
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    • 2009
  • The geometric distortion of image is one of the most important parameters that take effect on the accuracy of optical inspection systems. We propose a new correction method of the image distortion to increase the accuracy of PCB inspection systems. The model-free method is applied to correct the randomly distorted image that cannot be represented by mathematical model. To reduce the correction time of inspection system, we newly propose a grid reduction algorithm that minimize the number of grids by the quad-tree approach. We apply the proposed method to a PCB inspection system, and verify its usefulness through experiments using actual inspection images.

A Study on Machine Vision System and Camera Modeling with Geometric Distortion (기하학적 왜곡을 고려한 카메라 모델링 및 머신비젼 시스템에 관한 연구)

  • 계중읍
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.7 no.4
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    • pp.64-72
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    • 1998
  • This paper a new approach to the design of machine vision technique with a camera modeling that accounts for major sources of geometric 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 design and manufacturing as well as camera assembly. It is our propose 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 vision system is illustrated by simulation and experiment.

Burr and shape distorion in micro-grooving of optical componets (광학부품용 비세홈의 금형가공에 있어서 버와 형상변형에 관한 연구)

  • 임한석;안중환
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.04a
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    • pp.53-57
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    • 1996
  • The side burrs and shape distortion resulting from the micromachining of an array of V-shape microgrooves in optical components were experimentally invesigated and a simplified model for their formation is proposed. Burr/shpae distortion should be kept to a minimum level since they degrade the characteristics and performance of these parts. The focus of this study is on the influence of depth of cut and workpiece material. The workpiece materials use were brass, bronze and copper. From the obsevation of the chip shape and burr/shape distortion, the proposed model, that the compressive force at the cutting edge causess the ductile uncut chip material to flow plastically outward toward the free surface to result in a burr, was verified.

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Analysis of Optical Characteristics of Oil Immersion Lens in Aqueous Environment (액상유체 오일 이멀전 렌즈의 광학 물성치 해석)

  • Choi, Hae Woon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.11
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    • pp.18-23
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    • 2019
  • The oil immersion method can be used to create objective lenses with long working distances without sacrificing the focusing resolution for laser processing. In this study, a space in which air or oil can be filled was formed in the middle of a lens for analyzing the optical properties of a liquid-oil immersion lens. As the refractive media, air and oils of different refractive index values (1.2 and 1.5, respectively) were used. A simulation was conducted in the ZEMAX software environment using the ray-tracing technique, and the performance of the oil immersion lens was verified by determining its image distortion and focal length (FL) in each medium. In the case of air, the calculated FL was 0.813 mm, whereas the imaged FLs were 1.594 mm and 8.126 mm when the refraction indices were 1.2 and 1.5, respectively. The FL of an oil immersion lens could be increased considerably. In terms of image distortion, the oil immersion lens exhibited little distortion at the center in all cases, but different degrees of image distortion were observed at different points away from the center depending on the refraction index degree.

Dispersion Management and Optical Phase Conjugation in Optical Transmission Links with a Randomly Distributed Single-Mode Fiber Length

  • Lee, Seong-Real
    • Journal of information and communication convergence engineering
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    • v.11 no.1
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    • pp.1-6
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    • 2013
  • Suppressing or mitigating signal distortion due to group velocity dispersion and optical Kerr effects is necessary in ultra-high speed and long-haul wavelength division multiplexing (WDM) transmission systems. Dispersion management (DM), optical phase conjugation (OPC), and the combination of these two are promising techniques to compensate for signal distortion. In this paper, to implement a flexible optical WDM network, a new optical link configuration with a randomly distributed single-mode fiber (SMF) length and fixed residual dispersion per span in the combination of DM and OPC is proposed and investigated. The simulation results show that the best net residual dispersion (NRD) in the proposed optical links is +10 ps/nm, which is independent of pre- and postcompensation. The effective launch power of the WDM channel is increased more in the optical links with NRD = +10 ps/nm controlled by only precompensation. Furthermore, the system performance difference between the proposed optical link configuration with the best NRD and the conventional optical link with uniform distribution of the SMF length had little significance. Consequently, it is confirmed that the proposed optical link configuration with the best NRD is effective and useful for implementing a reconfigurable long-haul WDM network.

Compensation of Chromatic Dispersion and Self Phase Modulation in Long-haul Optical Transmission System using Mid-span Optical Phase Conjugator (Mid-span Optical Phase Conjugator를 이용한 장거리 광 전송 시스템에서의 색 분산과 자기 위상 변조의 보상에 관한 연구)

  • 이성렬;이윤현
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.4
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    • pp.576-585
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    • 2001
  • In this paper, we investigated the method of compensation for optical pulse shape distortion due to both chromatic dispersion and SPM(self phase modulation) in a single mode fiber We selected MSSI(mid-span spectral inversion) as compensation method using OPC(optical phase conjugator). We used EOP(eye-opening penalty) parameter in order to evaluate the efficiency of waveform distortion compensation. In this paper, we induced optimum pump power level in optical phase conjugator through analytic method of computer simulation. And we investigated input signal power range being able to maintain stable reception performance under the condition of optimum pump power. We verified the possibility of high performance optical transmission system realization through the inducement and application of optimum pump power, input signal power and in-line amplifier spacing, because power control is important in the compensation for optical pulse distortion.

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Analysis of Specific Problems in Laser Scanning Optical System Design

  • Joo, Won-Don
    • Journal of the Optical Society of Korea
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    • v.15 no.1
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    • pp.22-29
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    • 2011
  • We analyze aberrations in an optical laser printer system in order to know how to determine an allowable non-uniformity of the movement of a light spot, how to determine allowed variation of spot sizes, and how to minimize the influence of these deviations on technological errors. In this paper, the correction and the tolerance of distortion are analyzed by using the concept of zonal and global distortions. The tolerance of field curvature is also obtained from Gaussian beam properties. In order to reduce the change of the entrance pupil position and to make a more compact laser printer system the minimum size of the rotator is exactly derived from the geometry with the introduction of the shift angle of the input beam.

Self-starting vector phase conjugate laser oscillator in inverted Nd:YAG

  • Kim, D.H.;Udaiyan, D.;Green, R.P.M.;Crofts, G.J.;Damzen, M.J.
    • Journal of the Optical Society of Korea
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    • v.1 no.1
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    • pp.41-43
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    • 1997
  • We report the operation of a self-adaptive vector phase conjugate laser (VPCL) oscillator which compensates intracavity polarization distortion and wavefront aberration simultaneously. The VPCL in Nd:YAG gain media produce an output with energy of 125mJ in a 20ns single-longitudinal-mode pulse at 10Hz, which is unaffected by intracavity polarization distortion.

A Correction of the Keystone Distortion Using the Bilinear Interpolation Method in 3D Stereoscopic images (3차원 입체영상에서 양선형 보간법을 이용한 키스톤 왜곡 보정)

  • Lee, Seung-Woo;Song, Young-Jun;Kim, Nam
    • Proceedings of the Korea Contents Association Conference
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    • 2006.11a
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    • pp.524-527
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    • 2006
  • This paper discusses a method to efficiently remove the keystone distortion in images. The keystone distortion which generated during 2D image aquisition to realize 3D stereoscopic images is removed by the bilinear interpolation method. Usually, the keystone distortion in 2D images can remove by the optical equipment but the image processing is more effective than the optical equipment in consideration of efficiency or simplicity of the works. This method can be realized 3D stereoscopic image without the distortion.

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