Jump to content United States-English
HP.com Home Products and Services Support and Drivers Solutions How to Buy
» Contact HP

HP.com home


Technical Reports



» 

HP Labs

» Research
» News and events
» Technical reports
» About HP Labs
» Careers @ HP Labs
» Worldwide sites
» Downloads
Content starts here

 
Click here for full text: PDF

Characterizing and Estimating Block DCT Image Compression Quantization Parameters

Samadani, Ramin

HPL-2005-190

Keyword(s): compression; artifact reduction; image processing; sequential estimation

Abstract: This paper describes an algorithm for estimating quantization matrices from raster images previously compressed with JPEG. First, the space of commonly used quantization matrices is statistically characterized using over 15000 image files. The insights from this characterization are used to design the algorithm. The two stage algorithm first applies a new sequential estimation process to determine some individual Q matrix entries, and then applies shape- gain vector quantization to recover complete quantization matrices. Low average absolute error values are found for 124 images not used during training. In addition, the estimated Q matrices work well when applied to compression artifact reduction. Notes:

5 Pages

Back to Index

»Technical Reports

» 2009
» 2008
» 2007
» 2006
» 2005
» 2004
» 2003
» 2002
» 2001
» 2000
» 1990 - 1999

Heritage Technical Reports

» Compaq & DEC Technical Reports
» Tandem Technical Reports
Printable version
Privacy statement Using this site means you accept its terms Feedback to HP Labs
© 2009 Hewlett-Packard Development Company, L.P.