• 제목/요약/키워드: Laser Tomography

검색결과 131건 처리시간 0.023초

레이저 토모그래피와 화염구조선도에 의한 연소영역의 검토 (A Discussion of Combustion Regime Based on Laser Tomography and Flame Structure Diagram)

  • 김준효
    • 동력기계공학회지
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    • 제2권1호
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    • pp.17-24
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    • 1998
  • The combustion regime was discussed using a laser tomography and flame structure diagram. It was shown first how to represent the turbulent burning velocity and flame structural parameters in the dimensionless plane referred to as the flame structure diagram. And then, turbulent flame structure from the obtained images by laser tomography was compared with combustion regime in the Re-Da plane, one of the diagrams, specified by different researchers. As the result, the $u'/S_{L0}$ ratio at the boundary between the wrinkled laminar flame regime and reactant islands flame regime was found to be about 1.5.

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Scientific and Engineering Applications of Full-field Swept-source Optical Coherence Tomography

  • Mehta, Dalip Singh;Anna, Tulsi;Shakher, Chandra
    • Journal of the Optical Society of Korea
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    • 제13권3호
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    • pp.341-348
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    • 2009
  • We report the development of full-field swept-source optical coherence tomography (SS-OCT) in the wavelength range of 815-870 nm using a unique combination of super-luminescent diode (SLD) as broad-band light source and acousto-optic tunable filter (AOTF) as a frequency-scanning device. Some new applications of full-field SS-OCT in forensic sciences and engineering materials have been demonstrated. Results of simultaneous topography and tomography of latent fingerprints, silicon microelectronic circuits and composite materials are presented. The main advantages of the present system are completely non-mechanical scanning, wide-field, compact and low-cost.

FDML 방식 스위핑 광원을 사용한 SS-OCT 구현 (Realization of Swept Source-Optical Coherence Tomography using FDML Laser)

  • 엄진섭
    • 센서학회지
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    • 제20권1호
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    • pp.46-52
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    • 2011
  • In this paper, the swept source-optical coherence tomography system using frequency domain mode locked(FDML) laser has realized. The FDML swept source laser showed 55.03 kHz sweeping speed, 125 nm sweeping range, and 9 mW output optical power, which are the superiority of FDML laser compared to previous swept source lasers. Also, through the cross-sectional image captured at 5 frames per second for a mirror, a 1 mm-thickness glass plate, and a thumb bottom, the performance of the system has demonstrated.

SS-OCT 방식을 이용한 생체의 표피단면 영상 획득 (Acquirement of in vivo epidermal cross-sectional image by using swept source optical coherence tomography)

  • 김훈섭;임해진;엄진섭
    • 산업기술연구
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    • 제28권A호
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    • pp.163-166
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    • 2008
  • In this paper, the swept source optical coherence tomography system has realized using a free-space interferometer based on a beam splitter. Personal computer has completed the control for tunable wavelength laser digitally and the B-scan motor as well. From each experiment for an onion and a salmon egg, we confirmed that the in vivo epidermal cross-sectional images for them can be obtained appropriately.

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Broadband Wavelength-swept Raman Laser for Fourier-domain Mode Locked Swept-source OCT

  • Lee, Hyung-Seok;Jung, Eun-Joo;Jeong, Myung-Yung;Kim, Chang-Seok
    • Journal of the Optical Society of Korea
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    • 제13권3호
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    • pp.316-320
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    • 2009
  • A novel broadband wavelength-swept Raman laser was used to implement Fourier-domain mode locked (FDML) swept-source optical coherence tomography (SS-OCT). Instead of a conventional semiconductor optical amplifier, this study used broadband optical fiber Raman amplification, over 50 nm centered around 1545 nm, using a multi-wavelength optical pumping scheme, which was implemented with the four laser diodes at the center wavelengths of 1425, 1435, 1455 and 1465 nm, respectively, and the maximum operating power of 150 mW each. The operating swept frequency of the laser was determined to 16.7 kHz from the FDML condition of 12 km optical fiber in the ring cavity. The OCT images were obtained using the novel broadband wavelengthswept Raman laser source.

Guided-Wave Tomographic Imaging of Plate Defects by Laser-Based Ultrasonic Techniques

  • Park, Junpil;Lim, Juyoung;Cho, Younho
    • 비파괴검사학회지
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    • 제34권6호
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    • pp.435-440
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    • 2014
  • Contact-guided-wave tests are impractical for investigating specimens with limited accessibility and rough surfaces or complex geometric features. A non-contact setup with a laser-ultrasonic transmitter and receiver is quite attractive for guided-wave inspection. In the present work, we developed a non-contact guided-wave tomography technique using the laser-ultrasonic technique in a plate. A method for Lamb-wave generation and detection in an aluminum plate with a pulsed laser-ultrasonic transmitter and Michelson-interferometer receiver was developed. The defect shape and area in the images obtained using laser scanning, showed good agreement with the actual defect. The proposed approach can be used as a non-contact online inspection and monitoring technique.

광원의 비선형 파장스위핑이 보정된 SS-OCT (Swept Source-Optical Coherence Tomography Using New Recalibration Method for Nonlinear Sweeping Laser)

  • 엄진섭
    • 센서학회지
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    • 제21권1호
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    • pp.68-74
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    • 2012
  • In this paper, Frequency Domain Mode Locked(FDML) wavelength swept laser with 55.027 kHz sweeping speed and 125 nm sweeping range has realized, and also a new method for recalibrating a nonlinear frequency sweeping of a swept laser has proposed. The Swept Source-Optical Coherence Tomography system using the proposed method has performed. For a mirror surface, the system showed the very clean 2-dimensional image and the advanced image speed of 7 frames per sec compared to the previous recalibration method.