Development and applications of a non-linear discrete grey-level reconstruction method for electron tomography with a limited small number of images

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K04891
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 28030:Nanomaterials-related
• Research Institution: Kogakuin University
• Principal Investigator: Baba Norio 工学院大学, 情報学部(情報工学部), 教授 (80164896)
• Co-Investigator(Kenkyū-buntansha): 馬場 美鈴 工学院大学, 総合研究所(付置研究所), 研究員 (80435528)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 電子線トモグラフィ / 電子顕微鏡 / 逆問題 / 画像再構成 / 情報欠落問題

Outline of Final Research Achievements

Electron tomography based on the same principle as the medical X-ray CT is widely applied to various fields of biological and material science for 3D structural analysis with nano-order resolution. However, because in general the projection images of all directions are not acquired from the reason of instrumental specialty and electron physics, the depth resolution of a tomogram is considerably low. In addition, because it needs nearly 100 electron micrographs, it takes hours and there is a serious problem in practicality.
As a result of this research, we devised a new tomographic image reconstruction method to solve these problems and created the practical software. Even if the image acquisition time is shortened from 1/4 to 1/5, a clear tomographic image can be obtained without degrading the resolution along the depth direction. It is also useful for other CT such as medical X-ray CT, MRI, neutron CT, etc.

Free Research Field

電子光学

Academic Significance and Societal Importance of the Research Achievements

コンピュータ断層法（ＣＴ）では、全ての方向（0°～180°）の投影データが必要ですが、この研究で取り上げた電子線（ＣＴ）のように、限られた角度範囲（ここでの例で換算して、0°～140°）しかデータが得られないＣＴもあります。このようなとき、断層像は歪みぼやけた像となります。この問題を解決しました。与えられた情報だけから欠陥を補う新たな理論を構築しました。さらに、通常１°間隔で細かく投影データを取得する必要がありますが、放射線量を減らす必要から、この間隔を8°～10°と広げても鮮明な断層像が得られます。この演算方法を広く多くのＣＴ装置に組み込めば大きく貢献できると考えています。