image retrieval using markov random fields and global image features
In this paper, we propose a direct image retrieval framework based on Markov Random Fields (MRFs) that exploits the semantic context dependencies of the image. The novelty of our approach lies in the use of different kernels in our non-parametric density estimation together with the utilisation of configurations that explore semantic relationships among concepts at the same time as low-level features, instead of just focusing on correlation between image features like in previous formulations. Hence, we introduce several configurations and study which one achieve the best performance. Results are presented for two datasets, the usual benchmark Corel 5k and the collection proposed by the 2009 edition of the ImageCLEF campaign. We observe that, using MRFs, performance increases significantly depending on the kernel used in the density estimation for the two datasets. With respect to the the language model, best results are obtained for the configuration that exploits dependencies between words together with dependencies between words and visual features. For the Corel 5k dataset, our best result corresponds to a mean average precision of 0.32, which compares favourably with the highest value ever obtained, 0.35, achieved by Makadia et al. [22] albeit with different features. For the ImageCLEF09 collection, we obtained 0.32, as mean average precision.
markov processes nonparametric statistics