Externally Controlled In Situ SEM: Multi-Rate Scanning With Signal Regulation and Spatiotemporal Fusion

In situ scanning electron microscopy is crucial for investigating materials' properties. High-temperature in situ experiments are important for revealing the phase transitions and thermal deformations of materials. However, thermal electrons and noise in the high-temperature environment can cause image distortion. Reducing the influence of thermal electrons and noise is a key means to improve the quality of high-temperature imaging. Rapid scanning emerges as a key strategy to address this challenge, as it minimizes the duration of thermal electron interference on images. This study presents an externally controlled in situ image acquisition system that mitigates thermal electron accumulation through multi-rate scanning, incorporates a dual-stage signal regulator to compensate for signal attenuation during high-speed scanning, and integrates an image fusion algorithm to effectively balance noise suppression and detail preservation. Together, these components constitute a coordinated hardware-algorithm solution for high-temperature imaging. The results show that the acquisition system can obtain high-quality images at 1050°C, with a total image acquisition time of only 1.5 s, which is significantly faster than the 3.5 s of traditional systems. Compared to the conventional acquisition speed of 3.2 μs/pixel, the synthesized images exhibit an increase in SSIM and a decrease in NIQE within the temperature range of 900°C~1050°C. This method provides reliable technical support for the dynamic microstructure characterization of high-temperature materials and promotes the application of in situ SEM in extreme environments.