Three-dimensional interfaces for querying by example in content-based image retrieval

Image databases are widely exploited in a number of different contexts, ranging from history of art, through medicine, to education. Existing querying paradigms are based either on the usage of textual strings, for high-level semantic queries or on 2D visual examples for the expression of perceptual queries. Semantic queries require manual annotation of the database images. Instead, perceptual queries only require that image analysis is performed on the database images in order to extract salient perceptual features that are matched with those of the example. However, usage of 2D examples is generally inadequate as effective authoring of query images, attaining a realistic reproduction of complex scenes, needs manual editing and sketching ability. Investigation of new querying paradigms is therefore an important-yet still marginally investigated-factor for the success of content-based image retrieval. In this paper, a novel querying paradigm is presented which is based on usage of 3D interfaces exploiting navigation and editing of 3D virtual environments. Query images are obtained by taking a snapshot of the framed environment and by using the snapshot as an example to retrieve similar database images. A comparative analysis is carried out between the usage of 3D and 2D interfaces and their related query paradigms. This analysis develops on a user test on retrieval efficiency and effectiveness, as well as on an evaluation of users' satisfaction.