When short queries and short image annotations are used in text-based cross-language image retrieval, small changes in word us- age due to translation errors may decrease the retrieval performance because of an increase in lexical mismatches. In the ImageCLEF2005 ad- hoc task, we investigated the use of learned word association models that represent how pairs of words are related to absorb such
... [Show full abstract] mismatches. We compared a precision-oriented simple word-matching retrieval model and a recall-oriented word association retrieval model. We also investigated combinations of these by introducing a new ranking function that gener- ated comparable output values from both models. Experimental results on English and German topics were discouraging, as the use of word association models degraded the performance. On the other hand, word association models helped retrieval for Japanese topics whose translation quality was low.
