Image quality improvement of single shot grid-based dark-field X-ray imaging and its application|RISS 상세보기

다국어 초록 (Multilingual Abstract)

Dark-field X-ray imaging (DFXI) is a new method based on small-angle X-ray scattering (SAXS), unlike conventional X-ray imaging, which is based on absorption contrast. This novel imaging technique can detect information about microscopic structures below the spatial resolution that cannot be detected by absorption X-ray imaging. Among the different DFXI techniques, single-shot grid-based DFXI (SG-DFXI) is suitable for commercialization and application to multiple fields because it requires a single X-ray grid and a single exposure with great simplicity and minimal requirements on the setup alignment. However, the disadvantage of this method is low-quality images owing to the low sensitivity to X-ray scattering and spectral overlap artifacts. Additionally, the lack of research on materials effective in detecting SAXS information in the SG-DFXI system makes finding a suitable application challenging. Therefore, although SG-DFXI can easily obtain dark-field images, it has low practicality.
In this dissertation, for practical use, we proposed optimal design criteria for the SG-DFXI system and a motion blur technique to improve the quality of the dark-field image obtained with SG-DFXI. The optimal design of SG-DFXI could enhance the performance of the dark-field image in a limited system, and the motion blur technique removed spectral overlap artifacts. Additionally, we analyzed the material characteristics and particle size related to the dark-field signal obtained by SG-DFXI, demonstrating that SG-DFXI effectively detects objects with particle sizes of 100 nm–10 μm. Based on these properties, we applied SG-DFXI to detect low-density foreign bodies in food. Consequently, the proposed method improved the quality of the dark-field image by enhancing the performance of SG-DFXI and effectively eliminating spectral overlap artifacts. Furthermore, the dark-field image obtained with SG-DFXI showed that low-density foreign bodies with micrometer-scale porous structures could be more effectively detected than conventional X-ray images. In conclusion, the methods and analysis results proposed in this dissertation could increase the practical application of SG-DFXI. We expect the improved SG-DFXI based on the proposed method to be applied to different related fields.

번역하기

국문 초록 (Abstract)

암시야 X-선 촬영 기법은 기존의 흡수 기반의 X-선 촬영과 달리 소각 X-선 산란 기반의 새로운 영상 촬영 방법이다. 이 기술은 흡수 기반 X-선 영상으로 검출할 수 없는 공간 해상도 이하의 미세 구조에 대한 정보를 감지할 수 있다. 여러가지 암시야 X-선 촬영 기법 중, X-선 그리드를 사용하는 단일 촬영 그리드 기반 암시야 X-선 영상(single-shot grid-based dark-field X-ray imaging; SG-DFXI)은 암시야 영상을 빠르게 획득할 수 있고 영상 시스템 설치 비용이 적게 들기 때문에 상용화 및 다양한 분야에 적용하기 적합하다. 그러나 이 방법은 X-선 산란에 대한 민감도가 낮아서 암시야 X-선 영상의 성능이 상대적으로 낮고, 복잡한 물체를 촬영하는 경우 발생하는 스펙트럼 중첩 아티팩트로 인하여 낮은 화질의 암시야 X-선 영상이 획득된다는 단점이 있다. 뿐만 아니라 SG-DFXI 시스템에서 SAXS 정보를 검출하기 적합한 물체에 대한 연구가 부족하여 이를 효과적으로 적용할 수 있는 분야를 찾기가 어렵다. 따라서 SG-DFXI는 암시야 X-선 영상을 쉽게 획득할 수 있다는 장점에도 불구하고 실용성이 낮다는 단점이 있다.
본 논문에서는 SG-DFXI의 실용적인 사용을 위하여 SG-DFXI를 통해 획득되는 암시야 X-선 영상의 화질을 개선하고자 영상의 성능을 높일 수 있는 SG-DFXI의 최적 설계 기준과, 스펙트럼 중첩 아티팩트를 제거하기 위한 모션 블러 기술을 제안하였다. 또한 SG-DFXI에서 획득되는 암시야 신호와 관련된 물체의 특성과 입자 크기를 분석하여 SG-DFXI가 100nm에서 10μm의 입자 크기와 다공성 구조를 가진 물체를 감지하는 데 유용하다는 것을 보여주었고 이를 식품내 저밀도 이물질 검출에 적용하였다. 그 결과 제안된 방법은 SG-DFXI의 영상의 성능을 높이고 스펙트럼 중첩 아티팩트를 효과적으로 제거하여 암시야 X-선 영상의 화질을 개선시킬 수 있었다. 또한 SG-DFXI을 통해 획득한 암시야 X-선 영상은 기존 X-선 영상보다 마이크로미터 단위의 다공성 구조를 가지는 저밀도 이물질들을 효과적으로 검출할 수 있다는 것을 보여 주었고 개선된 SG-DFXI를 통해 저밀도 이물질을 더 명확하게 검출할 수 있었다. 결론적으로, 본 논문에서 제안한 방법들과 분석 결과는 SG-DFXI를 실용성을 높여줄 수 있었고, 이를 통해 SG-DFXI를 다양한 관련 분야에서 유용하게 적용할 수 있을 것으로 기대된다.

번역하기

암시야 X-선 촬영 기법은 기존의 흡수 기반의 X-선 촬영과 달리 소각 X-선 산란 기반의 새로운 영상 촬영 방법이다. 이 기술은 흡수 기반 X-선 영상으로 검출할 수 없는 공간 해상도 이하의 미...

목차 (Table of Contents)

Table of Contents
Table of Contents ································ ································ ··· i
List of Figures································ ································ ······· iv
List of Tables ································ ································ ······· vii
Abstract ································ ································ ············ viii

Table of Contents
Table of Contents ································ ································ ··· i
List of Figures································ ································ ······· iv
List of Tables ································ ································ ······· vii
Abstract ································ ································ ············ viii
Chapter 1 Introduction ································ ···························· 1
1.1. Overview of dark-field X-ray imaging ································ ····· 1
1.2. Research motivation and scope ································ ·············· 3
Chapter 2 Background and Basic Theories ································ ···· 6
2.1 Fundamentals of X-rays ································ ······················· 6
2.1.1 X-ray interaction with matter ································ ············ 6
2.1.2 X-ray absorption ································ ·························· 8
2.1.3 Small-angle X-ray scattering ································ ············ 9
2.2 Principle of SG-DFXI ································ ························ 12
2.2.1 X-ray grid ································ ································ · 12
2.2.2 Basic concept of SG-DFXI ································ ············· 14
2.2.3 Measurement of the visibility in SG-DFXI ··························· 16
2.2.4 Relationship between the dark-field signal and SAXS ·············· 21
Chapter 3 Optimal Design for SG-DFXI System ···························· 28
3.1 Introduction ································ ································ ···· 28
3.2 Materials and methods ································ ······················· 29
3.2.1 Correlation length ································ ························ 29
3.2.2 Visibility of the fringe pattern ································ ·········· 32
3.2.3 Window size ································ ······························ 34
3.2.4 Optimization criteria of SG-DFXI system ···························· 35
3.2.5 Experimental setup ································ ······················ 36
3.3 Results and discussion ································ ······················· 38
3.4 Conclusion ································ ································ ····· 42
Chapter 4 Eliminating Spectral Overlap Artifacts in SG-DFXI ·········· 44
4.1 Introduction ································ ································ ···· 44
4.2 Materials and methods ································ ······················· 45
4.2.1 Spectral overlap artifacts ································ ················ 45
4.2.2 Motion blurring effect ································ ··················· 47
4.2.3 Experimental setup ································ ······················ 50
4.3 Results and discussion ································ ······················· 51
4.4 Conclusion ································ ································ ····· 54
Chapter 5 Application of SG-DFXI to X-ray Food Inspection ············ 56
5.1 Introduction ································ ································ ···· 56
5.2 Materials and methods ································ ······················· 58
5.2.1 Effective materials for SG-DFXI ································ ······ 58
5.2.2 Experimental setup ································ ······················ 60
5.2.3 Quantitative performance evaluation ································ ·· 65
5.2.4 Statistical analysis ································ ······················· 65
5.3 Results and discussion ································ ······················· 66
5.4 Conclusion ································ ································ ····· 75
Chapter 6 Summary ································ ······························· 76
References ································ ································ ··········· 78
Abstract (in Korean) ································ ····························· 86

참고문헌 (Reference)

1. X-ray spatial frequency heterodyne imaging, B. Wu, Y. Liu, C. Rose-Petruck, G. J. Diebold, 100 061110, , 2012

2. Bi-Directional X-Ray Phase-Contrast Mammography, K. Scherer, F. Pfeiffer, F. Bamberg, A. Sztrókay-Gaul, K. Hellerhoff, S. Grandl, M. Chabior, L. Birnbacher, J. Herzen, D. Mayr, 9 e93502, , 2014

3. X-ray spatial harmonic imaging of phase objects, B. Ahr, A. Linkin, G. J. Diebold, C. Rose-Petruck, Y. Liu, 36 2209, , 2011

4. Quantitative x-ray dark-field computed tomography, T. Donath, M. Bech, F. Pfeiffer, C. David, R. Feidenhans’l, O. Bunk, 55 5529–5539, , 2010

5. Mesh-based phase contrast Fourier transform imaging, C. A. MacDonald, J. C. Petruccelli, S. Tahir, S. Bashir, 389 103–109, , 2017

6. Physicochemical characterization of drug nanocarriers, E. Berbel Manaia, M. Paiva Abuçafy, L. Chiavacci, J. A. Oshiro-Júnior, B. Lallo Silva, B. G. Chiari-Andréo, Volume 12 4991–5011, , 2017

7. X-ray Scattering Studies of Protein Structural Dynamics, M. B. Watkins, W. C. Thomas, N. Ando, S. P. Meisburger, 117 7615–7672, , 2017

8. Lens-term- and edge-effect in X-ray grating interferometry, I. Zanette, J. Herzen, F. Schaff, J. I. Sperl, A. Yaroshenko, M. Schüttler, F. Pfeiffer, J. Wolf, 6 4812, , 2015

9. High-speed terahertz imaging toward food quality inspection, K. Park, H. S. Chun, S.-W. Choi, H. J. Kim, G. Ok, 53 1406, , 2014

10. Hard-X-ray dark-field imaging using a grating interferometer, C. Brönnimann, P. Kraft, O. Bunk, M. Bech, F. Pfeiffer, C. David, E. F. Eikenberry, C. Grünzweig, 7 134–137, , 2008