IMPLEMENTATION OF VISUAL ROUTINES

Cognition of abstract visual shape properties and spatial relations go beyond object recognition. Ullman proposed visual routines¹⁶ as the mechanism for flexible creation of different abstract visual features, each routine being a sequence composed of more basic visual elemental operations. We re-examine visual routines, inspired by recent neurophysiological advances (Roelfsema et al., 2000) and computational models of the primate visual system and propose possible underlying mechanisms for implementing elemental operations upon which visual routines are based. Whereas previous approaches to visual routines emphasized boundary contour processing or filling-in of regions between contours, we focus on medial axes and image segmentation in addition to boundary contours for a more inclusive understanding of visual routines. We show, at least conceptually, that all visual routines can be interpreted in terms of image segments. This framework suits the extraction of various abstract shape properties necessary to produce visual routines which agree with human visual perception in tasks such as discrimination of spirals, texture segregation, size illusions and more.