Visual data exploration to feature space definition

Many image-related applications rely on the fact that the dataset under investigation is correctly represented by features. However, defining a set of features that properly represents a dataset is still a challenging and, in most cases, an exhausting task. Most of the available techniques, especially when a large number of features is considered, are based on purely quantitative statistical measures or approaches based on artificial intelligence, and normally are "black-boxes" to the user. The approach proposed here seeks to open this "black-box" by means of visual representations, enabling users to get insight about the meaning and representativeness of the features computed from different feature extraction algorithms and sets of parameters. The results show that, as the combination of sets of features and changes in parameters improves the quality of the visual representation, the accuracy of the classification for the computed features also improves. The results strongly suggest that our approach can be successfully employed as a guidance to defining and understanding a set of features that properly represents an image dataset.