Documentary makers, journalists, news editors, and other media professionals routinely require previously recorded audiovisual
material for new productions. For example, a news editor might wish to reuse footage shot by overseas services for the evening
news, or a documentary maker might require shots of Christmas trees recorded over the decades. Important sources for reusable
broadcasts are audiovisual broadcast archives, which preserve and manage audiovisual material. With digitization, media professional
can be given online access to video. This increases ease of access, but increases the need for search capabilities tailored
for the media professional. Search in audiovisual broadcast archives, then, is the subject of this thesis.
by investigating the search behavior of media professionals in current daily practice. To this end we perform a large-scale
log analysis of their search actions at a national audiovisual broadcast archive. Our analysis characterizes not only the
searches of media professionals, but also their purchasing behavior. In order to model the observed behavior we follow our
log analysis with a simulation experiment. Here we investigate simulation methods for recreating the searches and purchases
recorded in the archive to create evaluation testbeds.
In the second half of the thesis we turn to investigate the
use of state-of-art methods for retrieval with automatically generated content metadata from video, Specifically we focus
on their application for improving audiovisual fragment search in the audiovisual broadcast archive. We use logged searches
and purchases to define new test collections for retrieval evaluation. These are used as the basis for experiments aimed at
solving specific problems that are faced when searching with automatically generated descriptions of video content. Finally,
we combine state-of-the-art methods with the current daily practice of the archive, and investigate their potential combined
impact on search in audiovisual broadcast archives.
The contributions of this thesis include the characterization
of searching and purchasing behaviour of media professionals at a large audiovisual broadcast archive, and a framework for
simulating their logged queries and purchases. Contributions in the second half of the thesis include an in-depth user study
of how text queries should be mapped to visual concepts, a retrieval model that accounts for the temporal mismatch between
the speech and visual tracks in audiovisual material, and a set of experiments demonstrating the effectiveness of automatically
generated content metadata for improving retrieval in the audiovisual broadcast archive.