PDF readability enhancement on mobile devices

In the past, researchers studied readability enhancement of English articles for non-native English readers, either on paper reading or hypertext reading. Using a variety of methods, researchers were able to enhance the reading comprehension and the users' satisfaction on hypertext reading, such as changing content presentation with visual-syntactic text formatting (VSTF) format or Jenga format. In terms of dynamically changing content presentation for reading, one less explored format is Portable Document Format (PDF), which was traditionally viewed within a modern Web browser or Adobe Acrobat reader on the desktop. PDF format was standardized as an open format in 2008 and has been widely used to keep a fixed-layout content. However, a fixed layout document presents a challenge to apply existing transformation methods, not mention on mobile devices. In this paper, we present a system that uses a novel algorithm to decode a PDF document and apply content transformation to enhance its readability. Although we used Jenga format as an example to enhance the readability of PDF documents, we envision the proposed framework can be used to adopt different transformation methods. The system was implemented in a mobile device and we are able to apply a basic transformation to a PDF document at both the sentence and paragraph levels. The main contribution of this research is we extend previous work of readability enhancement from paper document and hypertext content to PDF documents. Current result is promising, and we believe it is worth further investigation to make PDF documents readable and accessible on the Web for different populations, such as non-native English readers, people with dyslexia or special needs, etc.