Support system for fine focusing and astigmatism correction using an auditory signal in scanning electron microscopy.
The current study describes a new support system for fine focusing and near-perfect astigmatism correction for scanning electron microscopy (SEM). The signal-to-noise ratio of a series of SEM images obtained from fast scan rates (TV scan) was adopted as a new metric for evaluating focus. Measured signal-to-noise ratio values were converted to an acoustic signal (sound wave frequency) using digital image processing techniques, enabling the SEM user to evaluate image focus using the auditory modality. Accurate focusing and correcting astigmatism in general-purpose SEM is traditionally time-consuming and difficult. The proposed system may substantially reduce the required operation time for fine focusing. Moreover, the system is relatively immune to noise, successfully supporting focus and astigmatism correction with very noisy SEM images. Our proposed focus support system may be helpful for general-purpose SEM observation of a variety of specimens under a wide range of operating conditions.
Department of Electrical Engineering, Faculty of Engineering, Kogakuin University, 2665-1 Nakano-machi, Hachioji, Tokyo 192-0015, Japan.
Eisaku
E
Oho
Engineering Division, Canon Software Inc., 2-4-11 Higashishinagawa, Shinagawa, Tokyo, 140-8526, Japan.
Kazuhiko
K
Suzuki
Department of Electrical Engineering, Faculty of Engineering, Kogakuin University, 2665-1 Nakano-machi, Hachioji, Tokyo 192-0015, Japan.
Sadao
S
Yamazaki
D001251:Astigmatism / Q000503:physiopathology*; D001306:Auditory Pathways / Q000503:physiopathology / Q000648:ultrastructure; D005403:Fixation, Ocular / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D059629:Signal-To-Noise Ratio
astigmatism correction; auditory modality; digital image processing; fine focusing; scanning electron microscopy; signal-to-noise ratio