Optimization Technique of PDF Files for Electronic Display Devices

Abstract

In recent times, reading on an electronic display device such as a tablet computer has become popular. One of the typical document formats, the PDF, is also used for printing prepress work flows and standardized as PDF⁄X-1a. This application requires quality of contents, and the highest-quality materials consisting pages need to be packed in a PDF. Although electronic browsing applications consider transmission costs and performances of display devices, the storage size of a created PDF must be somewhat limited. For this reason, a PDF file for electronic browsing is likely to be created by simply sub-sampling a PDF file made for prepress works. This causes a novel problem of readability of bitmap-type letters in inserted pictures or drawings, which does not occur in conventional printed media. In this paper, we propose a novel compression and optimization technique of PDF files for electronic display devices, maintaining readability similar to that of print media.