A Software Arcitecture and Toolkit for Picture Metadata

George Sotak
Eastman Kodak

Abstract

The Digital Image Group's DIG35 Metadata Specification has emerged and the standard representation for information associated with digital images (i.e., metadata). The recommended encoding for the DIG35 Metadata is XML. This is a wise choice in that XML allows users to tap into the wealth of tools available for XML. Most important of these is the XML Parser. There are two dominant API's for XML Parsers: the Document Object Model (DOM) and the Simple API for XML (SAX). Neither is adequate in terms of the access to DIG35 metadata because in-memory instances of the metadata's value are left in terms of strings. Therefore, an additional layer of activity is needed to interpret the string representation into a useful, type-based in-memory representation.

Kodak has been working on a solution to this problem in the broader context of a general architecture for picture metadata. This architecture comprises three levels: structure, semantics, and context. The structure level addresses the structural representation of the metadata. For the receiver of the metadata, it answers the question, "How do I group these bytes or characters into meaningful components?" Semantics concerns the conveyance of the meaning of the metadata. It answers questions like, "What assertion is intended by this sequence of components?" Context addresses the contextual form and usage of the metadata. There is a clear dependence between these levels. The translations of the context level rely on the well-formed meanings in the semantic layer. The semantic layer, in turn, relies on the structure layer for the well-formed representations.

The foundation of this architecture, the structural level, has been realized through an Object-Oriented Framework called the Picture Metadata Toolkit (PMT). The PMT is ideally suited to provide programmatic access to DIG35 metadata definitions and instances. In addition, the PMT provides the tools to easily translate from legacy metadata instances (e.g., Exif and Tiff) to DIG35 instances. This presentation is an overview of the general architecture for picture metadata and the facilities of the PMT. This presentation also details a Kodak initiative to Open Source the PMT.

Biography

George Sotak is a Research Associate in the Imaging Systems and Software Laboratory of the Eastman Kodak Company. He is currently the Group Leader of the Metadata Systems Group and Chief Architect of the Picture Metadata Architecture. His past assignments at Kodak include research and development of Visual Information Management technologies, and algorithm and system development for the application of image processing and analysis to all disciplines of microscopy. He earned a B.S. in Electrical Engineering and Applied Physics from Case Western Reserve University and a M.S. in Electrical Engineering from The Ohio State University. He is a Senior Member of the IEEE and a member of the Computer and Signal Processing Societies.

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