Image retrieval Theoretical analysis and empirical user studies on accessing information in images

摘要

The paper touches upon indexing and retrieval for effective searches of digitized images. Different conceptions of what subject indexing means are described as a basis for defining an operational subject indexing strategy for images. The methodology is based on the art historian Erwin Panofsky, and his work on renaissance paintings. On the basic of works of art he develops a theory about ways in which one analyses representational images. Panofsky describes three levels of meaning in a work of art which indicate a difference in presupposed knowledge i.e. nothing (or only practical experience), special knowledge about image codes, and special knowledge about history of ideas. The semiologist Roland Barthes has established a semiology for pictorial expressions based on advertising photos. Barthes uses the concepts denotation/connotation where denotations can be explained as the sober expression of signs and connotation as meanings relating to feelings or associations. A joint methodology is suggested between the two researchers and the methodology is implemented in analyzing press photos. Fields of application discussed include the messages in an image and the linking between information running from text, image to object. An empirical study, based on 17 newspaper archives, demonstrates user group requirements including archivists (creators), journalists (immediate users), and newspaper readers (end-users). A word association test is completed and the terms are used to build a user interface. The empirical analysis demonstrates how the results can be applied as the foundation for a semantic model.