Plasmon (or valence) excitation is an important source of inelastic scattering in high-resolution TEM because valence loss electrons are distributed very near to Bragg beams. Atomic core-shell excitations are localized scattering processes whose probability is very small. Thermal diffuse scattering is also a localized inelastic scattering but the large momentum transfer in this process results in the majority of TDS electrons being distributed in the angular range out of the objective aperture. This is partially equivalent to introducing an absorption factor in the elastic HRTEM image simulation, as illustrated in Chap. 6 , with electrons enclosed by the objective aperture contributing to the image. Therefore, valence excitation and phonon scattering are inelastic-scattering processes that must be considered in HRTEM image simulations.