NDLI: Generalized node splitting and bilevel image compression

Content Provider	IEEE Xplore Digital Library
Author	Helfgott, H.A. Storer, J.A.
Copyright Year	1997
Description	Author affiliation: Dept. of Comput. Sci., Brandeis Univ., Waltham, MA, USA (Helfgott, H.A.)
Abstract	Summary form only given. Among the methods for lossless compression of bilevel images, algorithms that do node splitting on context pixels obtain the highest compression ratios. For the most part, these methods use binary variables to do the splitting. Variables that can adopt more than two values are sometimes used, but each possible value of the variable always determines a separate child of a node. We put forward the use of splitting variables that can adopt a very large number of values, including intervals over the reals. At the same time, the number of children per node is kept small as needed. We use a greedy algorithm to repeatedly divide the range of the splitting variable so as to maximize entropy reduction at each step. Both non-local information, e.g., position, and functions on neighborhood pixels can go into tree-building. The resulting compression ratios are higher than those of traditional node-splitting methods. We also show that a context-based codebook, i.e. a function from the set of all possible contexts to the real interval [0,1], can be composed with the inverse of a function from the set of all possible contexts to the reals, such as a function based on Grey coding of the context bitstring, to produce a function from the reals to [0,1] that is very amenable to moderately lossy compression. Even though compression of the codebook is lossy, compression of the image itself is lossless.
File Size	52466
File Format	PDF
ISBN	0818677619
ISSN	10680314
DOI	10.1109/DCC.1997.582102
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	1997-03-25
Publisher Place	USA
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Image coding Computer science Pixel Greedy algorithms Entropy Gray-scale
Content Type	Text
Resource Type	Article
Subject	Computer Networks and Communications

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in