Research On High Temperature Image Data Acquisition And Image Processing Of Scanning Electron Icroscope

Scanning electron microscope(SEM)is the main application instrument to observe and characterize the micro nano size and study the surface morphology of materials.In the in-situ high temperature tensile test of samples using scanning electron microscope,due to the influence of thermo electrons emitted by high temperature samples and heating table,bright white stripes will appear in the scanning image of scanning electron microscope due to the periodic excitation of hot electrons.When the temperature is high enough,the scanning image will be completely bright white due to the interference of hot electrons.In order to solve the interference problem of scanning electron microscope in image acquisition and obtain clear in situ scanning image,the image acquisition system of scanning electron microscope is studied and the low quality image is processed.The main research contents include:(1)study the scanning principle,data acquisition principle,data transmission,amplification principle,scanning electron microscope control principle,thermo electron emission principle and other related theoretical knowledge of scanning electron microscope,understand the functions of scanning electron microscope,the working principle and use of modules,in-depth study of the relationship between thermo electron emission and heating temperature,and the influence of heating temperature on scanning electron emission The effect of tracing.(2)The scanning electron microscope of the research group is used to collect the images of the samples at different heating temperatures,and the thermo electron detection platform is designed.For the scanning images with thermo electron interference,the thermo electron voltage value of the corresponding interference is detected by the thermo electron detection platform.(3)The electromagnetic simulation analysis of heating filament is carried out to study the interference of magnetic field on scanning electron beam and secondary electron bombarded by electron beam.(4)The image edge detection algorithm is used to find the pixels interfered by the heated electrons,and the relationship between the pixels of the scanning image and the scanning time is used to make one-to-one correspondence between the relevant values of the collected thermo electron voltage and the relevant pixels.(5)The image processing algorithm is studied.The steepest descent method and the improved Longhorn algorithm are used to find the numerical relationship between the thermo electron voltage and the thermo electron interference to the image at different temperatures.(6)After collecting certain data,the scanning image repair test is carried out.The image data collected under different temperatures are processed in real time with image processing algorithm to get the scanning image which can remove the thermo electron interference.The scanning image processed by the algorithm is compared with the original scanning image to verify the effectiveness of the algorithm.