Mediation Between Central and Peripheral Processing:
Useful Knowledge Structures
Roger Browse
Abstract
This paper outlines a computational vision research project aimed at the development of
techniques for the mediation between central and peripheral processes. The key ingredients are
structural relations between image and scene domain hierarchies, and a representation which
emphasizes the dependencies that exist within the knowledge. These constructs may be used to
select areas of the image to process in greater detail on the basis of the progress of interpretation;
the nature of the task which is motivating the visual system; and the contents of both peripheral
and foveal vision.
Introduction
Information extraction is an essential component of intelligent behaviour. This extraction often
involves the selection of sequences of intense, localized processing within contexts of less
detailed global processing. The locomotion of an organism through its environment provides
locations from which detailed information may be obtained. Of course the extent to which
information may be received from locations nearby may vary, but it is always constrained by the
capabilities of the organism-1. Similarly the saccadic eye movements of the visual system,
together with the acuity structure of the retina, provides a sequence of select locations in the
visual environment which may be intensely processed within the context of acuity-limited
peripheral vision-2. Visual attention may also be viewed as the selection of locations for more
detailed processing, both within the information available in a single fixation of the eyes, and
within the knowledge which is involved in the visual processing-3. To extend the idea to its
limit, thought may be a sequence of availabilities of information within the mind-4.
Visual attention and thought have no directly observable manifestations as do locomotion and
eye movements, and hence the patterns of their operation must be inferred from psychological
experimentation and from introspection and will thus always remain speculative.
The interesting questions which arise are:
- Is there some uniform computational process which can mediate between detailed, local
information extraction and less detailed, global information extraction?
- What is the role of such a process in intelligence?
This paper describes part of a research project which is aimed at the development of answers to
these questions. The context is a computational vision system which interprets line-drawings of
human-like body forms-5 (The drawings are similar to those used to illustrate the movement
notation of Eshkol and Wachmann (1958)). Of particular concern is the interaction between
interpretation and the selection of locations to process with foveal acuity.