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Computational and Mathematical Methods in Medicine
Volume 2014, Article ID 495729, 7 pages
Research Article

Study on Construction of a Medical X-Ray Direct Digital Radiography System and Hybrid Preprocessing Methods

College of Communication Engineering, Chongqing University, Chongqing 400044, China

Received 21 March 2014; Revised 16 May 2014; Accepted 26 May 2014; Published 11 June 2014

Academic Editor: Peng Feng

Copyright © 2014 Yong Ren 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.


We construct a medical X-ray direct digital radiography (DDR) system based on a CCD (charge-coupled devices) camera. For the original images captured from X-ray exposure, computer first executes image flat-field correction and image gamma correction, and then carries out image contrast enhancement. A hybrid image contrast enhancement algorithm which is based on sharp frequency localization-contourlet transform (SFL-CT) and contrast limited adaptive histogram equalization (CLAHE), is proposed and verified by the clinical DDR images. Experimental results show that, for the medical X-ray DDR images, the proposed comprehensive preprocessing algorithm can not only greatly enhance the contrast and detail information, but also improve the resolution capability of DDR system.