Bioingenium at ImageCLEF 2012: Text and Visual Indexing for Medical Images

This paper describes the participation of the Bioingenium research group of Universidad Nacional de Colombia in the ImageCLEF2012 Medical Retrieval challenge, specifically in the ad-hoc image-based retrieval task. The methods used for solving textual and visual queries with which we submitted uni-modal runs are described. They were ranked 1st and 3rd respectively. These results have been obtained by using our own implementation of Okapi-BM25 weighting scheme for text retrieval, and by adding spatial layouts to the CEDD descriptors for visual retrieval. We also used these uni-modal features to learn multimodal representations using matrix factorization for solving visual queries. Despite the potential of multimodal indexes to improve the quality of visual queries, these experiments were not as successful as uni-modal indexes. We discuss the main findings of all these experiments.