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Analytical Cellular Pathology
Volume 36, Issue 1-2, Pages 37-44

Evaluations of Auto-Focusing Methods under a Microscopic Imaging Modality for Metaphase Chromosome Image Analysis

Yuchen Qiu,1 Xiaodong Chen,1,2 Yuhua Li,1 Wei R. Chen,3 Bin Zheng,4 Shibo Li,5 and Hong Liu1

1Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK, USA
2College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin, China
3Department of Engineering and Physics, University of Central Oklahoma, Edmond, OK, USA
4Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
5Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA

Copyright © 2013 Hindawi Publishing Corporation and the authors. 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.


Background: Auto-focusing is an important operation in high throughput imaging scanning. Although many auto-focusing methods have been developed and tested for a variety of imaging modalities, few investigations have been performed on the selection of an optimal auto-focusing method that is suitable for the pathological metaphase chromosome analysis under a high resolution scanning microscopic system.

Objective: The purpose of this study is to investigate and identify an optimal auto-focusing method for the pathological metaphase chromosome analysis.

Methods: In this study, five auto-focusing methods were applied and tested using metaphase chromosome images acquired from bone marrow and blood specimens. These methods were assessed by measuring a number of indices including execution time, accuracy, number of false maxima, and full width at half maximum (FWHM).

Results: For the specific condition investigated in this study, the results showed that the Brenner gradient and threshold pixel counting methods were the optimal methods for acquiring high quality metaphase chromosome images from the bone marrow and blood specimens, respectively.

Conclusions: Selecting an optimal auto-focusing method depends on the specific clinical tasks. This study also provides useful information for the design and implementation of the high throughput microscopic image scanning systems in the future digital pathology.