Getting Computers to See Information Graphics So Users Do Not Have to

Information graphics such as bar, line and pie charts appear frequently in electronic media and often contain information that is not found elsewhere in documents. Unfortunately, sight-impaired users have difficulty accessing and assimilating information graphics. Our goal is an interactive natural language system that provides effective access to information graphics for sight-impaired individuals. This paper describes how image processing has been applied to transform an information graphic into an XML representation that captures all aspects of the graphic that might be relevant to extracting knowledge from it. It discusses the problems that were encountered in analyzing and categorizing components of the graphic, and the algorithms and heuristics that were successfully applied. The resulting XML representation serves as input to an evidential reasoning component that hypothesizes the message that the graphic was intended to convey.