. This paper addresses four questions concerning control of attention: how to direct attention to novel or `interesting' events in the world, how to separate novel or interesting information from everything else, how to perform this segmentation of the world at multiple levels, how to develop perceptual machinery capable of this. To all four questions we provide answers arising from work in our WRAITH project. Each answer proves to be effective in both an engineering sense (having contributed to the control of an active vision robot in natural surroundings) and a scientific sense, having sufficient biological plausibility to be a working hypothesis about natural visual systems. 1 Introduction This paper is an expansion and revision of ideas introduced in an earlier publication [16] and presents new experimental results that strengthen and extend the arguments therein. It was Gibson [10] who first promoted the ecological approach to vision, according to which vision can only be proper...

Active vision is identified by a closed loop linking sensing with acting. Thus, an active vision system's behaviour is directly determined by what it senses. To date however, the responses produced by active vision systems have tended to be relatively low-level, generally designed to facilitate improved sensing, by enhancing the duration or speed of object tracking, for example, or optimising the focussed application of more intensive image processing. This is probably adequate if the active vision system is designed as a front end to other processes or to specialised application systems, or if it is a demonstration in support of a theoretical vision model. However, this leaves unanswered the problems of i) how to select an appropriate action when many different alternatives are available, and ii) how best to modify the behavioural repertoire of the system. These problems are especially important in two situations: firstly, when an autonomous system faces a novel situation and must respond adaptively without the benefit of a priori knowledge, and secondly, when systems attempt higher levels of perception and response, and links between the absolute properties of the incoming image data and the actual objects of perception become increasingly attenuated. This paper discusses methods for linking learning with active vision so that the behaviour of the system is optimised over time for the achievement of goals. We argue the necessity of system goals in learning vision systems, and discuss methods for propagating goals through all levels of loose hierarchies. In the last section we outline an architecture in which high and low level perception operate interactively and in parallel.