Real-Time Noise Filter for Extremely Low-Dose Experiments

Abstract Electron microscopy is a powerful technique used to study materials at the atomic scale. However, many samples are sensitive to electron irradiation. One way to reduce radiation damage is to observe the sample at low-dose conditions, although, at extreme low-dose conditions, each single frame of images is very noisy, which makes such experiments difficult. Since most of the specimens for high-resolution electron microscopy are periodic, a noise filter technique in Fourier space can be used to detect periodic regions by reducing the noise. Thus, we have developed a real-time filter based on the Wiener filter, which will work even for individual images under extreme low-dose conditions and can display noise-filtered images more than ten frames per second. This real-time noise filter facilitates demanding low-dose experiments by helping an operator find a good sample and to adjust the experimental conditions.