A model for the rapid interpretation of line drawings in early vision

Abstract According to the prevailing view, the elements of early visual processing arecharacterized by simple geometric properties such as length, orientation, andcurvature. We demonstrate in this chapter that this view must be revised—theelements of early vision need not be geometrically simple. Instead, they can becharacterized in terms of environmental relevance, computational architecture,and processing speed. We begin by summarizing the conventional view of earlyvision and point to several problems it encounters. We then re-examine therole played by the elements of early vision, arguing that it is advantageous forthem to describe environmentally relevant properties, even if these quantitiesare not always valid. As an illustration, we develop a computational model forthe rapid recovery of one important scene property from line drawings—thethree-dimensional orientation of objects. Data from recent visual searchexperiments in humans are presented in support of the model. Early vision