Color and texture applied to a signature-based bag of visual words method for image retrieval

This article addresses the problem of representation, indexing and retrieval of images through the signature-based bag of visual words (S-BoVW) paradigm, which maps features extracted from image blocks into a set of words without the need of clustering processes. Here, we propose the first ever method based on the S-BoVW paradigm that considers information of texture to generate textual signatures of image blocks. We also propose a strategy that represents image blocks with words which are generated based on both color as well as texture information. The textual representation generated by this strategy allows the application of traditional text retrieval and ranking techniques to compute the similarity between images. We have performed experiments with distinct similarity functions and weighting schemes, comparing the proposed strategy to the well-known cluster-based bag of visual words (C-BoVW) and S-BoVW methods proposed previously. Our results show that the proposed strategy for representing images is a competitive alternative for image retrieval, and overcomes the baselines in many scenarios.