Automatic Extraction of Semantic Descriptions from the Lecturer´s Speech

The number of digital lecture video recordings has increased dramatically since recording technology became easier to use. The accessibility and ability to search within this large archive are limited and difficult. Manual annotation is time-consuming and therefore useless. A promising approach is based on using the audio layer of a lecture recording to obtain semantic information about the lecture´s contents. The speech transcript and the words from the power point slides are sufficient to generate semantic metadata serialized in an OWL file. Two annotation methods are discussed, evaluated and compared to each other and to a perfectly annotated OWL file, as well as to an annotation based on a corrected transcript of the lecture.