Speech and Text-Image Processing in Documents

Speech and Text-Image Processing in Documents Marcia A. Bush Xerox Palo Alto Research Center 3333 Coyote Hill Road Palo Alto, CA 94304 ABSTRACT Two themes have evolved in speech and text image processing work at Xerox PARC that expand and redefine the role of recognition tech- nology in d~ument-oriented appficafions. One is the development of systems that provide functionality similar to that of text proces- sors but operate directly on audio and scanned image data. A second, related theme is the use of speech and text-nnage recognition to re- Irieve arbitrary, user-specified information from documents with sig- nal content. This paper discusses three research initiatives at PARC that exemplify these themes: a text-image editor[I], a wordspotter for voice editing and indexing[12], and a decoding framework for scanned-document content retrieval[4]. 1 The discussion focuses on key concepts embodied in the research that enable novel signal-based document processing functionality. 1. INTRODUCTION Research on application of spoken language processing to document creation and information retrieval has focused on the use of speech as an interface to systems that operate pri- marily on text-based material. Products of such work include commercially available voice transcription devices, as well as DARPA-sponsored systems developed to support speech recognition and database interaction tasks (e.g., the Resource Management[9] and Air Travel Information Systems[8] tasks, respectively). Similarly, work on text image processing has focused primarily on optical character recognition (OCR) as a means of transforming paper-based documents into manip- ulable (i.e., ASCH-based) electronic form. In both cases, the paradigm is one of format conversion, in which audio or im- age data are converted into symbolic representations that fully describe the content and structure of the associated document or query. Over the past few years, two themes have evolved in speech and text image processing work at Xerox PARC that expand and redefine the role of recognition technology in document- oriented applications. The first of these is the development of systems that provide functionality similar to that of text processors but operate directly on audio and scanned image data. These systems represent alternatives to the traditional format conversion paradigm. They are based on a principle of 1 Thanks to S. Bagley, R Chou, G. Kopec and L W'dcox for agreeing to have their work discussed here. "Ibis work ~ts a sample, rather than a ~!1 survey, of relevant speech and text-image research at PARC. partial document modeling, in which only enough signal anal- ysis is performed to accomplish the user's goal. The systems are intended to facilitate authoring and editing of documents for which input and output medium are the same. Examples include authoring of voice mail and editing of facsimile-based document images. A second, and related, research theme is the use of speech and text-image recognition to retrieve arbitrary, user-specified information from documents with signal content. The focus is again on partial document models that are defined in only enough detail to satisfy task requirements. Depending upon application, format conversion may or may not be a desired goal. For example, …

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