• Title, Summary, Keyword: Holographic method

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Quantitative Interpretation of Holographic Fringe by Using Phase Shifting Method and Digital Image Processing (위상변이법과 디지탈 영상처리를 이용한 홀로그래피 간섭무늬의 정량적 해석)

  • 고영욱;권영하;강대임;박승옥
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.9
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    • pp.1728-1735
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    • 1992
  • Holographic interferometry technique has been used for the measurement of whole-field deformation with high sensitivity. However there are some difficulties in quantitatively analyzing the holographic fringes. Recently, quantitative and automatic fringe analysis by using phase shifting method in interferometry has been studied in many fields. In this paper, a real time holographic interferometry system and a phase shifting method combined with digital image processing technique are employed to record and quantitatively analyze holographic fringe patterns. To evaluate our system and analyze errors, comparison of measured deformation with theoretical deformation of cantilever beam was carried out. The accuracy of 4.5% in our system was verified We have tried to apply this method to quantitatively measure the deformation of turbine blade under the bending force.

Application of Holographic Interferometry and 2-D PIV for HSC Convective Flow Diagnostics (Hele-Shaw Cell 내부의 열유동 해석을 위한 홀로그래픽 간섭계와 2차원 PIV의 적용)

  • Kim, Seok;Lee, Sang-Joon
    • Proceedings of the KSME Conference
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    • pp.682-687
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    • 2003
  • The variations of temperature and velocity fields in a Hele-Shaw convection cell (HSC) were investigated using a holographic interferometry and 2-D PIV system with varying Rayleigh number. To measure quasisteady changes of temperature field, two different measurement methods of holographic interferometry; double-exposure method and real-time method, were employed. In the double-exposure method, unwanted waves can be eliminated effectively using digital image processing technique and the reconstruction images are clear, but transient flow structure cannot be reconstructed clearly. On the other hand, transient convective flow can be reconstructed well using the real-time method. However, the fringe patterns reconstructed by the real-time method contain more noises, compared with the double-exposure method. Experimental results show a steady flow pattern at low Rayleigh numbers and a time-dependent periodic flow structure at high Rayleigh numbers. The periodic flow pattern at high Rayleigh numbers obtained by the real-time holographic interferometer method is in a good agreement with the PIV results.

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A Study on the Development of Chalcogenide-based ReRAM{Resistance RAM) Device with Holographic Lithography Method (Holographic Lithography 방법을 적용한 Chalcogenide-based ReRAM(Resistance RAM) 소자의 개발에 관한 연구)

  • Nam, Ki-Hyun;Chung, Hong-Bay
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.12
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    • pp.1014-1017
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    • 2009
  • In this study, we studied the nature of thin films formed by holographic photodoping chalcogenide thin films with for use in programmable metallization cell devices(PMC), a type of ReRAM. We formatted straight conduction pathway from the internal interferences of the diffraction gratings which is builded by the holographic lithography method. We investigated the resistance change of solid-electrolyte chalcogenide thin films varied in the applied voltage bias direction from about $1\;M{\Omega}$ to several hundreds of $\Omega$. The switching characteristics of the devices applied holographic lithography method was more improved than ultraviolet exposure condition. As a result of improved resistance change effects, we can analogize that the diffraction gratings is a kind of pattern for straight conduction pathway formation inside the chalcogenide thin films.

Validation of Digital Holographic Particle Velocity Measurement System (디지털 홀로그래피 입자 속도 계측시스템의 검증)

  • Roh, H.S.;Kang, B.S.
    • Journal of ILASS-Korea
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    • v.18 no.3
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    • pp.119-125
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    • 2013
  • Digital holographic particle velocity measurement system can be a promising optical tool for the measurements of three dimensional particle velocities. In this research, validation experiments for the digital holographic particle velocity measurement system were conducted with measuring the velocities of glass beads on a rotating disk. Uncertainty analysis was performed to identify the sources of all relevant errors and to evaluate their magnitudes. The measurement results of particle velocities obtained with digital holographic method are compared reasonably well with the known values within acceptable range of errors. Moreover, digital holographic method showed better performance compared with that of optical holographic system.

Measurement of Thermal Flow in a Hele-Shaw Convection Cell Using Holographic Interferometry and PIV Technique (홀로그래픽 간섭계와 PIV를 이용한 Hele-Shaw Convection Cell 내부 열유동 해석)

  • Kim Seok;Lee Sang-Joon
    • 한국가시화정보학회:학술대회논문집
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    • pp.35-38
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    • 2002
  • Variations of temperature and velocity fields in a Hele-Shaw Convection Cell (HSC) were measured using a holographic interferometry and PIV technique with varying Rayleigh number. Experimental results show a steady flow pattern at low Rayleigh numbers and a time-dependent periodic flow at high Rayleigh numbers. Two different measurement methods of holographic interferometry, double-exposure method and real-time method, were employed to measure the temperature field variations of HSC convective flow. In the double-exposure method, unwanted waves can be eliminated and reconstruction images are clear, but transient flow structure cannot be observed clearly. On the other hand, transient flow can be observed and reconstructed well using the real-time method. PIV results show that flow inside the HSC is periodic and the oscillating state is well matched with the temperature field results. The holographic interferometry and PIV techniques employed in this study are useful for analyzing the unsteady convective thermal fluid flows.

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A Study on Dichromated Gelatin for Recording of HOE (홀로그래픽 광학소자 제작을 위한 dichromated gelatin 연구)

  • Man Ho Jeong
    • Proceedings of the Optical Society of Korea Conference
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    • pp.112-114
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    • 1990
  • A method for fabrication of holographic optical elements (HOE) using dichromated gelatin (DGG) as a recording material is presented. we describe the holographic properties of the DGG and the processing techniques. Holographic characteristics of the DGG including exposure characteristics, diffraction efficiency and angular sensitivity are also discussed. The diffraction efficiency of the obtained holographic grating is about 84%.

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Holographic Grating Erasing Characteristics by Non-polarized Beam in Amorphous Chalcogenide Thin Films

  • Lee, Ki-Nam;Park, Jeong-Il;Chung, Hong-Bay
    • Transactions on Electrical and Electronic Materials
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    • v.7 no.3
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    • pp.141-144
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    • 2006
  • In the present work, we investigated the holographic grating erasing method by means of the optical method. It was formed the grating under the interference of holographic recording He-Ne laser beams on chalcogenide $As_{40}Ge_{10}Se_{15}S_{35}$ thin film with various film thickness and erased the holographic grating by non-polarized He-Ne laser beam. As the results, the recording grating erased the 80 % of formed grating by non-polarized He-Ne laser beam. It was confirmed that the erasing characteristics by non-polarized laser beam need to improve the focusing of beam and the control of beam intensity. And then it can be expected as the application possibility of rewritable holographic memory technology.

Temperature Field Measurements of Hele-Shaw Convection Cell Using a Holographic Interferometry (홀로그래픽 간섭계를 이용한 Hele-Shaw Convection Cell 내부 온도장 측정)

  • Kim, Seok;Lee, Sang-Joon
    • Proceedings of the KSME Conference
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    • pp.530-535
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    • 2001
  • Variations of temperature field in a Hele-Shaw convection cell (HSC) were measured using a holographic interferometry with varying Rayleigh number. Experimental results show a steady flow pattern at low Rayleigh numbers and a time-dependent periodic flow at high Rayleigh numbers. Especially, the period of oscillation at $Ra = 6.35{\times}10^6$ was 62 seconds. Two different measurement methods of holographic interferometry, double-exposure method and real-time method, were employed to measure the temperature field variations of HSC convective flow. In the double-exposure method, unwanted waves can be eliminated and reconstruction images are clear, but transient flow structure cannot be observed clearly. On the other hand, transient flow can be observed and reconstructed well using the real-time method. However, the fringe patterns reconstructed by the real-time method contain more noise, compared with the double-exposure method. The two holographic interferometer techniques employed complementary in this study were proved to be useful for analyzing the temperature field variations of unsteady thermal fluid flows.

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Temperature Field Measurements of Hele-Shaw Convection Cell Using a Holographic Interferometry (홀로그래픽 간섭계를 이용한 Hele-Shaw Convection Cell 내부 온도장 측정)

  • Kim, Seok;Lee, Sang-Joon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.11
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    • pp.1624-1631
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    • 2001
  • Variations of temperature field in a Hele-Shaw convection cell (HSC) were measured using a holographic interferometry with varying Rayleigh number. Experimental results show a steady flow pattern at low Rayleigh numbers and a time-dependent periodic flow at high Rayleigh numbers. Especially, the period of oscillation at Ra = 6.35 $\times$ 10$^{6}$ was 62 seconds. Two different measurement methods of holographic interferometry, double-exposure method and real-time method, were employed to measure the temperature field variations of HSC convective flow. In the double-exposure method, unwanted waves can be eliminated and reconstruction images are clear, but transient flow structure cannot be observed clearly. On the other hand, transient flow can be observed and reconstructed well using the real-time method. However, the fringe patterns reconstructed by the real-time method contain more noise, compared with the double-exposure method. The two holographic interferometer techniques employed complementary in this study were proved to be useful fur analyzing the temperature field variations of unsteady thermal fluid flows.

Diagnosis of HSC Convective Flow Using a Digital Holographic Interferometry and PIV System (디지털 홀로그래픽 간섭계와 PIV를 이용한 Hele-Shaw Cell 내부 열유동 해석)

  • Kim, Seok;Lee, Sang-Joon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.4
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    • pp.493-499
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    • 2004
  • Variations of temperature and velocity fields in a Hele-Shaw convection cell (HSC) were investigated using a holographic interferometry and 2-D PIV system with varying Rayleigh number. To measure quasi-steady variation of temperature field, two different measurement methods of holographic interferometry, double-exposure method and real-time method, were employed. In the double-exposure method, unwanted waves were eliminated effectively using a digital image processing technique. The reconstructed images are clear, but transient flow cannot be reconstructed clearly. On the other hand, transient convective flow can be reconstructed well using the real-time method. However, the fringe patterns reconstructed by the real-time method contain more noises, compared with the double-exposure method. Experimental results show a steady flow pattern at low Rayleigh numbers and a time-dependent periodic flow structure at high Rayleigh numbers. The periodic flow pattern at high Rayleigh numbers obtained by the real-time holographic interferometer method is in a good agreement with the PIV results.