Removal of DCT blocking artifacts using DC and AC filtering

TitleRemoval of DCT blocking artifacts using DC and AC filtering
Publication TypeConference Paper
Year of Publication2003
AuthorsIsmaeil, I. R., and R. K. Ward
Conference NameCommunications, Computers and signal Processing, 2003. PACRim. 2003 IEEE Pacific Rim Conference on
Pagination229 - 232 vol.1
Date Publishedaug.
KeywordsAC coefficients, AC filtering, DC coefficients, DC filtering, DCT blocking artifact removal, discrete cosine transforms, image coding, image processing, post-filtering algorithm, smoothing methods, transform coded images, transform coding

This paper introduces a post-filtering algorithm that reduces the blocking artifacts caused by quantizing to zero the high frequency DCT coefficients. First, the algorithm detects the blocks that only have a DC coefficient. Second, the blocking artifacts are reduced by averaging the DC coefficient of the block in question and the DC coefficients of the neighboring four 8 times;8 DCT blocks. These blocking artifacts are further reduced by predicting the low-frequency AC coefficients from the DC coefficient within a 3 times;3 array of blocks. Experimental results show that averaging the DC coefficients and predicting the low frequency AC coefficients definitely help to remove blocking artifacts in smooth background areas of the image.


a place of mind, The University of British Columbia

Electrical and Computer Engineering
2332 Main Mall
Vancouver, BC Canada V6T 1Z4
Tel +1.604.822.2872
Fax +1.604.822.5949

Emergency Procedures | Accessibility | Contact UBC | © Copyright 2021 The University of British Columbia