 
Summary: Improving 3D Reconstruction from STEM Data
A.F. Koschan,* M. Mercimek,* M.A. Abidi, * A.Y. Borisevich,** A.R. Lupini,** and S. J.
Pennycook**
* IRIS Laboratory, ECE Dept, University of Tennessee, 1508, Middle Dr, Knoxville, TN 37996
** Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN
37831
The successful implementation of spherical aberration correction in the scanning transmission
electron microscope (STEM) is one of the most significant accomplishments in electron optics in the
last few decades. Correction of magnetic lens aberrations to the third order has led to significant
improvements in point resolution and signaltonoise ratio, expanding the range of accessible lattice
spacings into the subÅngstrom regime [1]. The greatly reduced depth of field of the aberration
corrected STEM probes has also enabled threedimensional imaging by optical sectioning [2]. Fig. 1
shows a 3D rendered STEM data set of a (Pt, Au)/TiO2 catalyst sample. The data has been acquired
using a VG Microscopes HB603U STEM at ORNL. The metal particles appear elongated in the
depth direction, reflecting the defocus spread of the STEM probe. Deconvolution techniques similar
to those used in confocal optical microscopy can help achieve closer correspondence with the real
structure of the material [2].
Assume that the image formation is modeled as a 3D convolution nohi += , where i is the 3D
stack of 2D recorded images (see Fig. 2 for illustration), o is the 3D unknown observed object, h is
the 3D point spread function (PSF), n is the noise, and denotes the 3D convolution operator. Blind
