Arrangement: A Spatial Relation Comparing Part Embeddings and its Use in Medical Image Comparisons

A qualitative spatial relation called “arrangement” is proposed in this paper. Given an image, the relation describes the sequence in which neighbors of each part are situated around it. “Arrangement” is closely related to directional relations and extends the notion of directional relations to parts that have complex shapes. The relation captures a perceptual gestalt of the image. A metric for comparing “arrangements” is also proposed. The metric is obtained by interpreting “arrangements” in terms of Voronoi diagrams. The metric allows robust use of the relation in real-world situations. An application of the relation to similarity retrieval in medical (cardiac) image databases is also discussed. The metric is evaluated as a pictorial-based means for retrieving images from this cardiac database and is compared with retrieval using human experts. These efforts are aimed at the development of a medical image database system which will be indexed primarily on pictorial information content.