Computer Processing Of Electron Microscope Images

Computer Processing of Electron Microscope Images

Towards the end of the 1960s, a number of quite different circumstances combined to launch a period of intense activity in the digital processing of electron micro graphs. First, many years of work on correcting the resolution-limiting aberrations of electron microscope objectives had shown that these optical impediments to very high resolution could indeed be overcome, but only at the cost of immense exper imental difficulty; thanks largely to the theoretical work of K. -J. Hanszen and his colleagues and to the experimental work of F. Thon, the notions of transfer func tions were beginning to supplant or complement the concepts of geometrical optics in electron optical thinking; and finally, large fast computers, capable of manipu lating big image matrices in a reasonable time, were widely accessible. Thus the idea that recorded electron microscope images could be improved in some way or rendered more informative by subsequent computer processing gradually gained ground. At first, most effort was concentrated on three-dimensional reconstruction, particu larly of specimens with natural symmetry that could be exploited, and on linear operations on weakly scattering specimens (Chap. l). In 1973, however, R. W. Gerchberg and W. O. Saxton described an iterative algorithm that in principle yielded the phase and amplitude of the electron wave emerging from a strongly scattering speci men.

Computer Processing of Electron Microscope Images

Principles of Electron Optics, Volume 4

Principles of Electron Optics: Second Edition, Advanced Wave Optics provides a self-contained, modern account of electron optical phenomena with the Dirac or Schrödinger equation as a starting point. Knowledge of this branch of the subject is essential to understanding electron propagation in electron microscopes, electron holography and coherence. Sections in this new release include, Electron Interactions in Thin Specimens, Digital Image Processing, Acquisition, Sampling and Coding, Enhancement, Linear Restoration, Nonlinear Restoration – the Phase Problem, Three-dimensional Reconstruction, Image Analysis, Instrument Control, Vortex Beams, The Quantum Electron Microscope, and much more. - Includes authoritative coverage of many recent developments in wave electron optics - Describes the interaction of electrons with solids and the information that can be obtained from electron-beam techniques - Includes new content on multislice optics, 3D reconstruction, Wigner optics, vortex beams and the quantum electron microscope