|
Showing 1 - 2 of
2 matches in All Departments
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."
|
You may like...
Loot
Nadine Gordimer
Paperback
(2)
R383
R318
Discovery Miles 3 180
Loot
Nadine Gordimer
Paperback
(2)
R383
R318
Discovery Miles 3 180
|
Email address subscribed successfully.
A activation email has been sent to you.
Please click the link in that email to activate your subscription.