Abstract: Graphical queries for the purpose of searching for pictorial information are of growing interest in areas where pictures provide valuable information, including, for instance, design, architecture, and engineering. Sketching graphical queries is a natural way of revealing the visual appearance of objects one has in mind. Björn Gottfried develops computationally effective concepts for dealing with shape, in particular imprecise and incomplete sketched shapes. He exemplarily applies his method using graphical queries to search for historical objects. Specifying objects graphically, he shows that the new method is in fact capable of dealing with imprecise sketches. Generally speaking, the notion of positional-contrast is introduced. It defines how patterns can be robustly dealt with. That is, the new representation distinguishes patterns by how they relate with regard to spatial relations. This notion can be applied for several purposes, including pattern recognition, motion analysis, and texture analysis

Abstract: In the geographic domain shape features are of concern for several objects, such as borders between countries and counties as well as other administrative units, highways, coastlines, rivers, and other objects determining the infrastructure of a country such as telecommunication networks: we have to deal with shape features of those objects in the context of spatial planning and spatial databases. Defining Gestalt features of shapes, however, is a challenging issue. While in computer vision many features have been devised emphasis has been put on precision. The complementary approach consists in defining features which are not precise but allow shape properties to be defined at the categorical level. As a consequence those features are closely related to human perception and as such appropriate as comprehensible features, aiding in searching spatial databases for specific objects. Additionally those features are cheaper from the computational point of view: they compactly characterise shapes and they can equally compactly be employed in the context of storage, comparison, and retrieval.