Congratulations to James Mountstephens for passing his PhD examination

Wednesday 17 October 2007

"The automatic recognition of objects in visual scenes, both dynamic and static, is an important and highly-challenging computational task and typical approaches function purely on patterns found in visual features extracted directly from the scene image. Object recognition in people, however, may be influenced by prior contextual knowledge of co-occurrence patterns between real-world objects present in scenes and the derivation and application of this type of knowledge is the primary motivation of this work. In a novel fashion, knowledge of object co-occurrence is derived from patterns of co-occurring words derived from linguistic corpora and used to extend the hybrid video annotation architecture of Hoogs et al, itself based around the hierarchical linguistic knowledge base, WordNet. In addition to extending Hoogs’ architecture with corpus-derived contextual knowledge, recognition in multi-object scenes is guided by a model of selective visual attention due to Itti and Koch which is used to sequentially build an object-level context for a given scene. Two systems - LHACCOR (Linguistic Hierarchy Applying Corpus Context to Object Recognition) and VHACCOR (Visual Hierarchy Applying Corpus Context to Object Recognition) are presented to explore these ideas. LHACCOR retains Hoogs’ use of the WordNet noun hierarchy and VHACCOR extends Hoogs further by adapting a class hierarchy to the capability of the available visual processing rather than using the preset structure like WordNet, that is not explicitly designed around visual distinctions between classes. For VHACCOR, whatever classes are confused at a visual level must be distinguished by context. These two systems have been tested with natural, uncontrived scenes and display some improvement over a purely visual approach."