Image processing enhancement of high-resolution TEM micrographs of nanometer-size metal particles

Abstract

The high-resolution TEM detectability of lattice fringes from metal particles supported on substrates is impeded by the substrate itself. This effect appears in both amorphous and crystalline substrates. In the former case, it is due to substrate-generated phase contrast features; in the latter case it is due to the intermixing of fringes from particle and substrate. Single value decomposition (SVD) and Fourier filtering (FFT) methods were applied to standard high resolution micrographs to enhance lattice resolution from particles as well as from crystalline substrates. SVD produced good results for one direction of fringes, and it can be implemented as a real-time process. Fourier methods are independent of azimuthal directions and allow separation of particle lattice planes from those pertaining to the substrate, which makes it feasible to detect possible substrate distortions produced by the supported particle. This method, on the other hand, is more elaborate, requires more computer time than SVD and is, therefore, less likely to be used in real-time image processing applications. © 1989.