A visual tool for capturing the knowledge of expert image interpreters: a picture is worth more than a thousand words

This paper describes a system, KAGES (Knowledge Acquisition for Geographic Expert Systems), being developed to use visual means to extract the expertise of image interpreters. The system presents an image either as a single band or as various combinations of bands and allows an expert to use a mouse to point at or draw around features of interest. It then allows the user to interact with the system to confirm or adjust the identifying characteristics that the system suggests define the feature. These characteristics are not confined to pixel characteristics, and their relationship between image bands but, also includes spatial analysis capabilities. This paper also discusses some of the problems associated with the visual representation of the elicited knowledge and the verification of that knowledge. In order to verify a spatial rule, the human image interpreter needs to see it. For expert systems the usual way to view a rule is as an if-then-else triplet. This may be an unfamiliar construct to a user who works with visual cues, and may result in problems with verification