Image fragment matching in practice: applications and supplementary tools

Andrzej Sluzek
(Nanyang TU, Singpore)

Abstract:

Image fragment matching is a very general tool with a wide range of prospective applications (sometimes very different from the originally envisaged use in visual information retrieval). In this presentation, we focus on three highly diversified applications. First, the idea of visual object formation is discussed, where the system generalizes similarities between fragments from dataset images to form "visual objects", i.e. pieces of mutually similar fragments repetively encountered in the dataset. Such "visual objects" are defined without any knowledge of image domain/contents. In most cases, they correspond to the actual objects frequently appearing in the dataset images, i.e. a certain level of "visual understanding" of the dataset domain can be automatically established. In the second application, we show that image fragment matching can be a useful mechanism in face detection and/or recognition. We argue that it can objectively model the subjective concepts of "similar faces", "similar eyes", "similar foreheads", etc. Fragments of such faces can be identified in images of unpredictable backgrounds.

Additionally, if certain assumptions are added, a very simple face authentication algorithm can be built (of performances below the top state-of-the-art results, but highly useful in diversified applications). The third example presents how image fragment matching can be used to estimate the visibility quality in traffic applications. Two numerical measures of visibility are proposed, and the results on extremely difficult data are presented. The approach can be prospectively used to automatically adjust the vehicle speed to the current road conditions. Finally, a few supplementary algorithms are briefly discussed. The algorithms can be either used as alternatives in selected steps of image fragment matching or can further improve the results of matching.