Center Weighted Median Filters and Their Applications to Image Enhancement

Sung Jea Ko, Yong Hoon Lee

Research output: Contribution to journalArticlepeer-review

991 Citations (Scopus)


The center weighted median (CWM) filter, which is a weighted median filter giving more weight only to the central value of each window, is studied. This filter can preserve image details while suppressing additive white and/or impulsive-type noise. The statistical properties of the CWM filter are analyzed. It is shown that the CWM filter can outperform the median filter. Some relationships between CWM and other median-type filters, such as the Winsorizing smoother and the multistage median filter, are derived.In an attempt to improve the performance of CWM filters, an adaptive CWM (ACWM) filter having a space varying central weight is proposed. We show that the ACWM filter is an excellent detail preserving smoother that can suppress signal-dependent noise as well as signal-independent noise.Sung-Jea Ko (S'86-M'88) received the B.S. degree in electronics engineering in 1980 from Korea University, Seoul, Korea, and the M.S. and Ph.D. degrees in electrical and computer engineering from State University of New York at Buffalo, in 1986 and 1988, respectively.From 1981 to 1983 he was a member of the technical staff of Daewoo Telecom, Seoul, Korea, working on the design of data communication systems. Since 1988 he has been with the department of electrical and computer engineering, the University of Michigan, Dearborn, where he is currently an Assistant Professor. He received a Rackham research award from the University of Michigan in 1991. His main research interests are one- and multidimensional signal processing, VLSI signal processing, and statistical pattern recognition.Young Hoon Lee (S'81-M'85) received the B.S. and M.S. degrees in electrical engineering from Seoul National University, Seoul, Korea, in 1978 and 1980, respectively, and the Ph.D. degree in systems engineering from the University of Pennsylvania, Philadelphia, in 1984.From 1984 to 1988, he was an assistant professor at the Department of Electrical and Computer Engineering, State University of New York at Buffalo. Since 1989 he has been with the Department of Electrical Engineering at the Korea Institute of Science and Technology, where he is currently an Associate Professor. His research activities are in the areas of one- and two-dimensional signal processing.

Original languageEnglish
Pages (from-to)984-993
Number of pages10
JournalIEEE Transactions on Circuits and Systems
Issue number9
Publication statusPublished - 1991 Sept
Externally publishedYes

ASJC Scopus subject areas

  • General Engineering


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