Real time spherical aberration correction with high resolution transmission election microscope based on active image processing method
| Project/Area Number |
61550041
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
応用物理学一般(含航海学)
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| Research Institution | Osaka Electro-Communication university |
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Principal Investigator |
IKUTA Takashi Professor,Osaka Elevtro-Communication University, 工学部, 教授 (20103343)
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| Co-Investigator(Kenkyū-buntansha) |
ENDOH Hisamitsu Assistant Professor, Osaka University, 工学部, 助手 (20027907)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Image processing / Transmission electron microscope / Electron lens / Spherical aberration / Aberration correction / Active image processing / 3D filtering / 非線形結像項の除去 / 焦点位置変調 / 非線形干渉項の除去 |
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| Research Abstract |
A concept of new spherical aberration correction technique with high resolution transmission electorn microscorp has been in the present study (1986-1987, Grant-in-Aid for Scientific Research (C) ). Main aims of this study are to achieve the detailed theoretical analysis and to confirm the applicability of this new technigue in the high resolution transmission electron microscopy.
On the theoretical study, at first, a simple band pass filtering based on the active defocus modulation and sinusoidally weighted image intergration has been proposed with preliminary experimental results obtained by a coherently illuminated optical microscorp. Next, this approach has been extended to the spherical aberration correction in the coherent optical system. The weighting function for this processing, synchronized to the defocus modulation can be also analytically derived in the case of the spherical aberration in the coherent optical system. A simulative experiment of the spherical aberrayion correc
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tion in the optical microscope has beeb successfully achieved using an objective lens with variable spherical aberration coefficient. The processed image shows better quality compared with the original slightly defocused image correspondig to the 'Scherzer' focus, which is considered to be best one with non-processed images.
In the final stage of the present theoretical study, the concept of this defocus modulation processing has been extended to the 3D processing. From the analysis, It is pointed out that the nonlinear imaging effect caused by strongly scattered object can be removed by the active 3D convolver using both the defocus and sample position modulation.
As to the experiments in the transmission electron microscope, at first, a mini-static lens has been constructed to achieve the very fast defocus modulation. However, this lens has been resigned to use in the present processing because of that the image translation is very large with the defocus modulation, caused by insufficient mechanical accuracy. Then only a simple band pass filter function has been examined as to the verification of the present processing in the transmission electron microscope. From experimental results, this filter function has been well confirmed in consideration of the residual image translation with the defocus alteration. From this, the present spherical aberration correction technigue is expected to be applicable to the high resolution transmission electron microscope under sufficient adjustment of the electron optical system with the image translation. Less
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Report
(2 results)
Research Products
(10 results)
