PDF Enhancements Tools for a Digital Library: pdfJbIm and pdfsign
| Authors | |
|---|---|
| Year of publication | 2010 |
| Type | Article in Proceedings |
| Conference | DML 2010 Towards a Digital Mathematics Library |
| MU Faculty or unit | |
| Citation | |
| Web | |
| Field | Computer hardware and software |
| Keywords | jbig2enc; JBIG2; PDF size optimization; compression; DML; digital signature; JB2; DjVu; pdfJbIm; pdfsign; DML-CZ; EuDML |
| Description | This paper describes several innovative PDF document enhancements and tools that can be used when building a digital library. The main result presented in this paper is the PDF re-compression tool, developed using the jbig2enc encoder called pdfJbIm. This re-compression tool enables the size of the original bitonal PDFs to be, on average, halved. Some modifications to the jbig2enc encoder that increase the compression ratio even further are also described here. Together with another program, the pdfsizeopt.py by Péter Szabó, we have managed to decrease PDF storage size to such an extent that the transmission needs of a digital library were significantly reduced. We report the storage saving results that we have achieved on The Czech Digital Mathematics Library DML-CZ. We have downsized the PDF corpus to 43% of its original size. We also describe pdfsign tools for batch digital signature stamping of PDF documents. |
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