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Volume 2017 (2017), Article ID 1097142, 8 pages
https://doi.org/10.1155/2017/1097142
Research Article

Postprocessing Algorithm for Driving Conventional Scanning Tunneling Microscope at Fast Scan Rates

1Department of Mathematics, University of Florida, Gainesville, FL 32611, USA
2Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6487, USA
3Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
4Department of Physics and the Quantum Theory Project, University of Florida, Gainesville, FL 32611, USA

Correspondence should be addressed to X.-G. Zhang; ude.lfu@zgx

Received 23 June 2017; Accepted 30 October 2017; Published 20 November 2017

Academic Editor: Ying Zhao

Copyright © 2017 Hao Zhang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We present an image postprocessing framework for Scanning Tunneling Microscope (STM) to reduce the strong spurious oscillations and scan line noise at fast scan rates and preserve the features, allowing an order of magnitude increase in the scan rate without upgrading the hardware. The proposed method consists of two steps for large scale images and four steps for atomic scale images. For large scale images, we first apply for each line an image registration method to align the forward and backward scans of the same line. In the second step we apply a “rubber band” model which is solved by a novel Constrained Adaptive and Iterative Filtering Algorithm (CIAFA). The numerical results on measurement from copper(111) surface indicate the processed images are comparable in accuracy to data obtained with a slow scan rate, but are free of the scan drift error commonly seen in slow scan data. For atomic scale images, an additional first step to remove line-by-line strong background fluctuations and a fourth step of replacing the postprocessed image by its ranking map as the final atomic resolution image are required. The resulting image restores the lattice image that is nearly undetectable in the original fast scan data.