Archival moving imagery in the digital environment

Moving image media record much of the history of the twentieth century, and as such form an important aspect of our cultural heritage. Although potentially of great importance to both the education and commercial sectors, much of this store of knowledge is not accessible, because its content is not documented. Digitisation is being considered as a means of making historic footage more accessible by allowing moving imagery to be displayed via the Internet. Further, digitisation of still and moving imagery opens the possibility of relieving the time-consuming and expensive process of descriptive cataloguing, by using automated indexing and retrieval techniques, based on the physical attributes present in the imagery, such as colour, texture, shapes, spatial and spatiotemporal distribution. These techniques, developed by the computer science community, are generically known as Content Based Image Retrieval (CBIR). But will this type of image retrieval answer moving image archive users' information requirements? A project is being undertaken which researches the information needs of users of such archives; one of the objectives of this project is determine whether CBIR techniques can be used to answer these requirements. An analysis of requests for moving image footage received by eleven representative film collections determined that nearly 70% of the requests were for footage of a uniquely named person, group, place, event or time, and in many cases a combination of several of these facets. These are data that require to be documented in words. From this and other analyses, it may be determined that digitisation and automatic indexing and retrieval techniques do not at present offer an alternative to the textual subject descriptive process necessary for access to information stored in the form of moving imagery.