Presentation on theme: "Image metadata: interoperability and exchange Michael Day UKOLN, University of Bath Changing Images: the Role of Photographic Collections."— Presentation transcript:
Image metadata: interoperability and exchange Michael Day UKOLN, University of Bath Changing Images: the Role of Photographic Collections in a Digital Age, Finnish Museum of Photography, Helsinki, Finland, September 2003
SEPIA Conference, Helsinki, Finland, September 2003 Presentation overview Metadata: –Some definitions –Image-specific metadata issues –Diversity of standards Interoperability issues: –Collection-level description –Integrating retrieval –Object exchange Some conclusions
SEPIA Conference, Helsinki, Finland, September 2003 Metadata Definitions: "Data about data" About both digital and non-digital objects Primarily concern function, e.g.: –Resource discovery, retrieval or use –Resource management, preservation and continuing access –etc.
SEPIA Conference, Helsinki, Finland, September 2003 Image metadata (1) Concept-based retrieval: –Based on the interpretation and description of images in terms of what they are and what they represent (Rasmussen, 1997) –Methods: –Free-text 'captions' –Assignment of index terms from controlled vocabularies –Problems with subjectivity and 'aboutness'
SEPIA Conference, Helsinki, Finland, September 2003 Image metadata (2) Different levels of meaning (theory) –Erwin Panofsky - three levels (derived from studies of Renaissance art): –Primary or natural subject matter, forms, objects, events, expressions, etc. (pre-iconographical description) –Secondary or conventional subject matter, … themes, concepts (iconographical analysis) –Intrinsic meaning or content, deals with 'symbolical' values (iconological interpretation) –Sara Shatford Layne - distinguished between what a picture is (objectively) 'of' and (more subjectively) 'about' –Retrieval based on answering the questions: –Who? What? When? Where?
SEPIA Conference, Helsinki, Finland, September 2003 Case study (1) Subject (general) Object (specific) People (e.g., numbers, type) Action (the main activities being depicted) Location (geographical location) Photographer (name of the creator) Image Type (e.g., document, photograph, etc.) Collection (provenance, e.g., "Picture Post") Picture Attribute (e.g, black & white, layout, etc) Personality (the basis for a person search) Natural World (features) Mood Setting … Hulton Archive (Getty Images) online search In addition to a title and caption, each image has a number of metadata attributes, including some of:
SEPIA Conference, Helsinki, Finland, September 2003 Case study (2)
SEPIA Conference, Helsinki, Finland, September 2003 Case study (3)
SEPIA Conference, Helsinki, Finland, September 2003 Case study (4)
SEPIA Conference, Helsinki, Finland, September 2003 Image metadata (3) Initial conclusions: –Need for additional information (metadata) to facilitate retrieval from different perspectives –Image description is not perfect, suffers (like all other human-created metadata) from subjectivity –Language of descriptions a barrier to retrieval –there are some image-specific subject schemes (e.g., Art & Architecture Thesaurus, ICONCLASS) but these do not cover all image types –No realistic alternative until content-based image retrieval (CBIR) techniques are able to identify the semantic content of images
SEPIA Conference, Helsinki, Finland, September 2003 Metadata standards (1) Format diversity: –Multiple standards and implementations developed to support different communities and functions –Some examples …
SEPIA Conference, Helsinki, Finland, September 2003 Metadata standards (2) Cultural heritage community: Initiatives include: –SPECTRUM - the UK Museum Documentation Standard –VRA (Visual Resources Association) Core Categories –AMICO Data Dictionary –SCRAN Data Standard Specific focus on: –discovery; rights management; provenance Main characteristics of domain: –not only concerned with images; linked with digitisation initiatives; describes objects as well as the images derived from them; some convergence, e.g. with Dublin Core
SEPIA Conference, Helsinki, Finland, September 2003 Metadata standards (3) Digitisation: Initiatives include: –NISO Z AIIM : Data Dictionary -- Technical Metadata for Digital Still Images –Metadata Encoding and Transmission Standard (METS) Specific focus on: –structure; digitisation processes; rights management; preservation; object exchange Main characteristics of domain: –fast developing area; many promising implementations in XML, e.g. NISO Metadata for Images in XML (MIX) for Z39.87; modular approaches
SEPIA Conference, Helsinki, Finland, September 2003 Metadata standards (4) Geospatial metadata: Initiatives include: –FGDC (US Federal Geographic Data Committee) Content Standard for Digital Geospatial Metadata (CSGDM) –ISO Geographical information -- Metadata Specific focus on: –geographical information; spatial data; GIS Main characteristics of domain: –large schemas; not only concerned with images; convergence of existing standards development on ISO 19115
SEPIA Conference, Helsinki, Finland, September 2003 Metadata standards (5) Format diversity: –Inevitable - metadata schemas need to be fit for their purpose (function) –Images are highly heterogeneous –But leads to an increased need for the sharing of experiences (and schemas) across domains –A need for registries of metadata schemas? –Also causes potential problem with interoperability –Three broad approaches to the problem (described here): Collection-level description Integrating retrieval and access Object exchange
SEPIA Conference, Helsinki, Finland, September 2003 Collection description (1) Collection-level description: –Provides descriptions at a higher level of granularity –"… Can provide an overview of a large number of items, and such overviews may be useful where large amounts of item-level detail may not be appropriate" (Johnston, 2002) –Implicit in many forms of archival description –e.g., ISAD(G) (General International Standard Archival Description), EAD (Encoded Archival Description) –Offers the potential for interoperability at the collection level
SEPIA Conference, Helsinki, Finland, September 2003 Collection description (2) Collection-level description used in: –RSLP (Research Support Libraries Programme) –Analytic model of collections (2000) –Metadata schema –NOF (New Opportunities Fund) Digitisation programme –NOF Portal –JISC Information Environment Potential problems: –Differing concepts of what a "collection" is –Uneven implementation –Does it fulfil user needs?
SEPIA Conference, Helsinki, Finland, September 2003 Integrating retrieval (1) Solves heterogeneity by mapping common metadata attributes (for retrieval) –Tends to be at item level –Main approaches: –Cross-searching (e.g., ANSI/NISO Z39.50) –Metadata harvesting (e.g, the Open Archives Initiative Protocol for Metadata Harvesting) –No need to change the native format of the metadata –Mappings to intermediate formats e.g. OAI-PMH is currently based on the use of simple Dublin Core
SEPIA Conference, Helsinki, Finland, September 2003 Integrating retrieval (2) Dublin Core metadata element set –Maintained by Dublin Core Metadata Initiative (DCMI) –Defines 15 element metadata standard designed for resource discovery (e.g., ANSI/NISO Z ) –Mission: 1.Developing metadata standards for discovery across domains 2.Defining frameworks for the interoperation of metadata sets, and 3.Facilitating the development of community- or disciplinary-specific metadata sets that are consistent with items 1 and 2
SEPIA Conference, Helsinki, Finland, September 2003 Integrating retrieval (3) Case study: the SCRAN resource base: –Derives metadata from various cultural heritage institutions in Scotland –Metadata needs to be non-specific enough to be helpful to the non-specialist user –SCRAN data standard influenced by other standards, notably Dublin Core and SPECTRUM –Elements include: Title and statement of responsibility, caption + record details (e.g., Subject, Who, Where, Description, Date, Image Copyright, etc.)
SEPIA Conference, Helsinki, Finland, September 2003 Application profiles (1) Application profiles: –A concept that allows the local use, refinement and extension of metadata schemas developed elsewhere –Need for registries of metadata schemas –DCMI Registry "… to promote the discovery, reuse and extension of existing semantics, and to facilitate the creation of new vocabularies" (http://dublincore.org/dcregistry/) –CORES Registry (RDF-based)
SEPIA Conference, Helsinki, Finland, September 2003 Application profiles (2) Case study: The FILTER project: –Focusing Images for Learning & Teaching - an Enriched Resource (JISC-funded) –Led by Institute of Learning and Research Technology (ILRT), University of Bristol –Project aims: –To encourage the use (reuse and repurposing) of images in pedagogical contexts –To develop exemplar learning objects (cross- domain) –To produce a database of these learning objects and the images used in them
SEPIA Conference, Helsinki, Finland, September 2003 Application profiles (3) The FILTER project (continued) –Metadata schema –an application profile of Dublin Core –extensions to cover image and tutorial (learning object) specific categories –Database: –Search for images or tutorials –Browse by the highest-level subject categories –Browse by image type –Results demonstrate how the images are used in the context of the tutorial
SEPIA Conference, Helsinki, Finland, September 2003
Object exchange (1) Interoperability may mean more than cross- database or cross-domain resource discovery: –A need to support: –The exchange of objects between repositories and: Other repositories Users –The reuse (and repurposing) of objects –Long-term preservation –Solutions based on: –Encapsulations of data and metadata
SEPIA Conference, Helsinki, Finland, September 2003 Object exchange (2) The Metadata Encoding and Transmission Standard (METS) –Digital Library Federation initiative –Supported by the Network Development and MARC Standards Office of the Library of Congress –Origins in library digitisation initiatives –XML Schema –Greater focus on technical metadata than in traditional interoperability contexts, e.g.: –Structural, technical (formats, etc), descriptive, administrative metadata, etc.
SEPIA Conference, Helsinki, Finland, September 2003 Object exchange (3) METS (continued): –Modular design - can 'inherit' metadata from other standards (extension schemas), e.g. –technical metadata from Z39.87 –resource discovery metadata from Dublin Core, MARC or MODS –The type of technology needed to implement metadata for preservation - METS is understood as a type of OAIS Archival Information Package (AIP) –METS has been implemented by digitisation initiatives in libraries, OCLC Digital Archive, etc. –METS Implementation Registry available:
SEPIA Conference, Helsinki, Finland, September 2003 Some conclusions Interoperability standards can help: –Users to find and access relevant information (images) –The main function (for now) may be to help direct users to specific image collections or services –Much interesting development in this area –Institutions (repositories) to exchange objects with other repositories –Fast developing area –Synergies with object management and preservation
SEPIA Conference, Helsinki, Finland, September 2003 Acknowledgements UKOLN is funded by Resource: the Council for Museums, Archives and Libraries, the Joint Information Systems Committee (JISC) of the UK higher and further education funding councils, as well as by project funding from the JISC and the European Union. UKOLN also receives support from the University of Bath, where it is based.