PDF document restoration and optimization during image enhancement

ABSTRACT

We present a document processing method that addresses some of the practical challenges in image enhancement for digital photo album in PDF documents. With the advent of digital offset presses, consumer photo books are becoming increasingly popular, and most such workflows convert the consumer's photos and layout into PDF documents. In order to produce appealing photo albums from consumer photographs, some form of automatic enhancement is usually required, and this enhancement is often done late in the workflow just before printing, and therefore it is done on the PDF file. If each and every PDF generation tool simply inserted a single complete image each time an image appeared in the document, then the process of opening a PDF document, iterating through the document, extracting, enhancing, and replacing images, and then saving the enhanced document would be relatively easy. Unfortunately, PDF generation tools often violate that assumption in two ways. Firstly, large images are often written as a set of small images in strips or tiles, which visually appear to be a single image. Secondly, an image in a PDF document may be reused in the document on different position and pages; directly enhancing images without the consideration of the reuse model could result in great increase in the document size and poor system performance. Therefore, image reconstruction and document optimization were performed in our PDF photo album enhancement solution.

REFERENCES

• 1: "PDF Reference", Adobe system Incorporated.
• 2: "Acrobat Core API Reference" Adobe Developer Technologies.
• 3: Zomet, A.; Levin, A.; Peleg, S.; Weiss, Y.. "Seamless image stitching by minimizing false edges." IEEE Transactions on Image Processing, Volume 15, Issue 4, April 2006 Page(s): 969 -- 977
• 4: "Image alignment and stitching", Handbook of Mathematical Models in Computer Vision, pages 273--292. Springer, 2005.

INDEX TERMS

Primary Classification:
  I. Computing Methodologies
  I.7 DOCUMENT AND TEXT PROCESSING
      I.7.2 Document Preparation
          Subjects: Photocomposition/typesetting

Additional Classification:
  I. Computing Methodologies
  I.7 DOCUMENT AND TEXT PROCESSING
      I.7.2 Document Preparation
          Subjects: Multi/mixed media; Desktop publishing

General Terms:
Algorithms

Keywords:
PDF optimization, document enhancement, image stitching