Thresholded Weighted Median Filters for Ringing Reduction in Processed Images

Author

Beermann, Markus ; Jalil, Adeel ; Ohm, Jens-Rainer

Author_Institution

RWTH Aachen Univ.

fYear

2005

fDate

Oct. 30 2005-Nov. 2 2005

Firstpage

1

Lastpage

4

Abstract

In this paper, we present how thresholded weighted median filters (WMFs), can significantly improve visual as well as objective quality of images affected by ringing. Ringing is identified by its structural properties and WMFs are chosen according to these structures. Since WMFs are concerned with the relative values of their input but do not consider its absolute values, we explicitly enforce a limited filter output. In this paper we analyze the formation of ringing and match thresholded WMFs for example applications. For image resampling, we are able to obtain a significantly decreased amount of ringing. As a post-filter of a lossy wavelet-coder, typical PSNR gains around 0.4 dB are obtained while visually, ringing is reduced to a very pleasing extent

Keywords

image coding; image sampling; median filters; wavelet transforms; image quality; image resampling; limited filter output; lossy wavelet-coder; processed images; ringing artifacts reduction; structural analysis; thresholded weighted median filters; Discrete cosine transforms; Filtering; Focusing; Frequency; Image coding; Image processing; Image sequences; Low pass filters; PSNR; Wavelet transforms;

fLanguage

English

Publisher

ieee

Conference_Titel

Multimedia Signal Processing, 2005 IEEE 7th Workshop on

Conference_Location

Shanghai

Print_ISBN

0-7803-9288-4

Electronic_ISBN

0-7803-9289-2

Type

conf

DOI

10.1109/MMSP.2005.248556

Filename

4013977