• 제목/요약/키워드: optical distortion

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REGISTRATION OF MICROSCOPIC SECTION IMAGES BASED ON A RADIAL DISTORTION MODEL

  • Lee, Hoo-Sung;Yun, Il-Dong;Kim, Dong-Sik
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2009.01a
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    • pp.303-306
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    • 2009
  • Registration of microscopic section images from an organism is of importance in analyzing and understanding the function of an organism. Microscopes usually suffer from the radial distortion due to the spherical aberration. In this paper, a correction scheme for the intra-section registration is proposed. The correction scheme uses two corresponding feature points under the radial distortion model. Proposing several variations of the proposed scheme, we extensively conducted experiments for real microscopic images. Iterative versions of the correction from multiple feature points provide good performance for the registration of the optical and scanning electron microscopic images.

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Analysis of Laser Weldment Distortion in the EDFA LD Pump Packaging (광신호 증폭기 EDFA LD 펌프 패키징 레이저 용접부 변형 해석)

  • Gang, Dae-Hyeon;Son, Gwang-Jae;Yang, Yeong-Su
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.1
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    • pp.139-146
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    • 2001
  • This paper presents a study on heat transfer and residual distortion analysis of laser welded EDFA(Erbium Doped Fiber Amplifier) LD(Laser Diode) Pump using the finite element method. In the production process of LD Pump in light-wave communication system, ferrule and saddle are welded by Nd-YAG laser. These parts experience thermal and mechanical effect during heating and cooling cycle with the laser welding. Thus distortion happens in the laser-welded packaging, and it makes an error in detecting the light signal translate through optical fiber in LD Pump. The amount of final displacement produced by the laser welding is predicted using the finite element method. And the optimal shape of saddle is proposed with the results of numerical analyses to minimize the displacement.

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Distortion Calibration and FOV Adjustment in Video See-through AR using Mobile Phones (모바일 폰을 사용한 비디오 투과식 증강현실에서의 왜곡 보정과 시야각 조정)

  • Widjojo, Elisabeth Adelia;Hwang, Jae-In
    • Journal of Broadcast Engineering
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    • v.21 no.1
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    • pp.43-50
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    • 2016
  • In this paper, we present a distortion correction for wearable Augmented Reality (AR) on mobile phones. Head Mounted Display (HMD) using mobile phones, such as Samsung Gear VR or Google's cardboard, introduces lens distortion of the rendered image to user. Especially, in case of AR the distortion is more complicated due to the duplicated optical systems from mobile phone's camera and HMD's lens. Furthermore, such distortions generate mismatches of the visual cognition or perception of the user. In a natural way, we can assume that transparent wearable displays are the ultimate visual system which generates the least misperception. Therefore, the image from the mobile phone must be corrected to cancel this distortion to make transparent-like AR display with mobile phone based HMD. We developed a transparent-like display in the mobile wearable AR environment focusing on two issues: pincushion distortion and field-of view. We implemented our technique and evaluated their performance.

Demonstration of CSRZ Signal Generator Using Single-Stage Mach-Zehnder Modulator and Wideband CMOS Signal Mixer

  • Kang, Sae-Kyoung;Lee, Dong-Soo;Cho, Hyun-Woo;Ko, Je-Soo
    • ETRI Journal
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    • v.30 no.2
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    • pp.249-254
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    • 2008
  • In this paper, we demonstrate an electrically band-limited carrier-suppressed return-to-zero (EB-CSRZ) signal generator operating up to a 10 Gbps data rate comprising a single-stage Mach-Zehnder modulator and a wideband signal mixer. The wideband signal mixer comprises inverter stages, a mixing stage, and a gain amplifier. It is implemented by using a 0.13 ${\mu}m$ CMOS technology. Its transmission response shows a frequency range from DC to 6.4 GHz, and the isolation response between data and clock signals is about 21 dB at 6.4 GHz. Experimental results show optical spectral narrowing due to incorporating an electrical band-limiting filter and some waveform distortion due to bandwidth limitation by the filter. At 10 Gbps transmission, the chromatic dispersion tolerance of the EB-CSRZ signal is better than that of NRZ-modulated signal in single-mode fiber.

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Dispersion Managed Optical Transmission Links with an Artificial Distribution of the SMF Length and Residual Dispersion per Span

  • Lee, Seong-Real
    • Journal of information and communication convergence engineering
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    • v.12 no.2
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    • pp.75-82
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    • 2014
  • Dispersion management (DM), optical phase conjugation (OPC), and the combination of DM and OPC are promising techniques to compensate for optical signal distortion due to group velocity dispersion and nonlinear Kerr effects. The system performance improvement in DM links combined with OPC has been reported; however, the fixed residual dispersion per span (RDPS) usually used in these links restricts the flexibility of link configuration. Thus, in this paper, a flexible optical link configuration with artificially distributed single-mode fiber (SMF) lengths and RDPS in the combination of DM and OPC is proposed. Simulation results show that the best artificial distribution pattern is the gradually descending distribution of SMF lengths and the gradually ascending distribution of RDPS, as the number of fiber spans is increased, regardless of the average RDPS, the optimal net residual dispersion, and the dispersion coefficient of the dispersion compensating fiber.

Dispersion-Managed Links for WDM Transmission Arranged by Linearly or Nonlinearly Incremented Residual Dispersion per Span

  • Lee, Seong-Real
    • Journal of information and communication convergence engineering
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    • v.15 no.4
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    • pp.205-211
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    • 2017
  • Combining dispersion-managed optical links with midway optical phase conjugation (OPC) is a possible method of compensating for optical signal distortion due to group velocity dispersion and nonlinear Kerr effects. Although an improvement in the performance of these optical links has been reported, the fixed residual dispersion per span (RDPS) that is typically used restricts the flexibility of link configurations. Thus, in this paper, a flexible dispersion-managed link configuration, comprising artificial distributions of linearly/nonlinearly incremented RDPS, is proposed. Simulations show that a descending distribution of RDPS before the midway OPC, and an ascending distribution of RDPS after the midway OPC, gives the best artificial distribution pattern as the number of fiber spans is increased, regardless of the RDPS incrementation method.

Scanning confocal microscope by direct oscillation of an optical fiber (광섬유의 직접 구동에 의한 공초점 현미경)

  • 김종배;류광현;박두성;노정은;권남익
    • Korean Journal of Optics and Photonics
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    • v.14 no.1
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    • pp.80-84
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    • 2003
  • We have constructed a scanning confocal microscope by directly oscillating an optical fiber in two different ways. Either a piezoelectric transducer or a tuning fork was used for the oscillation. Six frames of $640{\times}480$ pixel image were obtained in a second with piezoelectric oscillation and only one image of the same size was obtained in a second with tuning fork oscillation. Oscillation of optical fiber did not cause amy distortion of confocal images.

Broadband Analog Optical Transmitter using Feedforward Compensation Circuit (피드포워드 보상회로를 적용한 광대역 광송신기의 특성)

  • Jang Joon-Woo;Choi Woon-Kyung;Choi Young-Wan;Moon Yon-Tae
    • 한국정보통신설비학회:학술대회논문집
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    • 2006.08a
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    • pp.15-18
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    • 2006
  • We have proposed a broadband analog feedforward optical transmitter using a wideband $180^{\circ}$ hybrid coupler instead of conventional frequency-sensitive phase shifter with the narrow bandwidth property using a wideband $180^{\circ}$ hybrid coupler, the wide-band linearization technique enhances the linearity of the feedforward optical transmitter. In two-tone cases, the $3^{rd}-IMD$ products was enhanced more than 10 dB in 385 MHz range(1.375$\sim$l.76 GHz).

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Dispersion-managed Transmission Links with the Non-midway Optical Phase Conjugator (Non-midway 광 위상 공액기를 갖는 분산 제어 링크)

  • Lee, Seong-Real
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2017.05a
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    • pp.744-746
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    • 2017
  • The maximum number of fiber spans is induced in disoersion-managed optical links with the non-midway optical phase conjugator (OPC) for the compensation of the distorted WDM signals due to the group velocity dispersion (GVD) are evaluated and compared.

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Dispersion-managed Transmission Links with the Non-midway Optical Phase Conjugator (Non-midway 광 위상 공액기를 갖는 분산 제어 링크)

  • Lee, Seong-Real
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2017.10a
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    • pp.671-673
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    • 2017
  • The maximum number of fiber spans is induced in disoersion-managed optical links with the non-midway optical phase conjugator (OPC) for the compensation of the distorted WDM signals due to the group velocity dispersion (GVD) are evaluated and compared.

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