標題: Image contrast enhancement based on a histogram transformation of local standard deviation
作者: Chang, DC
Wu, WR
電信工程研究所
Institute of Communications Engineering
關鍵字: adaptive contrast enhancement;histogram transformation;local standard deviation (LSD);radiography
公開日期: 1-Aug-1998
摘要: The adaptive contrast enhancement (ACE) algorithm, which uses contrast gains (CG's) to adjust the high-frequency components of images, is a well-known technique for medical image processing. Conventionally, the CG is either a constant or inversely proportional to the local standard deviation (LSD), However, it is known that conventional approaches entail noise overenhancement and ringing artifacts, In this paper, we present a new ACE algorithm that eliminates these problems. First, a mathematical model for the LSD distribution is proposed by extending Hunt's image model. Then, the CG is formulated as a function of the LSD. The function, which is nonlinear, is determined by the transformation between the LSD histogram and a desired LSD distribution. Using our formulation, it can be shown that conventional ACE's use linear functions to compute the new CG's, It is the proposed nonlinear function that produces an adequate CG resulting in little noise overenhancement and fewer ringing artifacts. Finally, simulations using some X-ray images are provided to demonstrate the effectiveness of our new algorithm.
URI: http://hdl.handle.net/11536/32478
ISSN: 0278-0062
期刊: IEEE TRANSACTIONS ON MEDICAL IMAGING
Volume: 17
Issue: 4
起始頁: 518
結束頁: 531
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