IAM@ImageCLEFPhotoAnnotation 2009: Naïve Application of a Linear-Algebraic Semantic Space

This paper describes Southampton’s submissions to the 2009 ImageCLEF photo annotation task. For the task we used an annotation system based on the idea of constructing semantic spaces, which was developed previously at Southampton. To represent the image content, we used a combination of different SIFT and Colour-SIFT features detected using the difference-of-Gaussian and MSER techniques. These features were converted into a visual term representation by applying vector quantisation using a codebook learnt from a hierarchical k-means clustering. In terms of EER and AUC, the annotator performs reasonably well, however, it struggles when evaluated using the hierarchical measure proposed for the task, due to the way the annotation confidences are thresholded.