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For files not identical at the bit level, it is difficult to determine if in fact the content and layout of the file is identical, even when they have the exact same file size and name. In this situation the document objects defined in the file together with their attributes need to be analyzed and, if they are formatted differently, in such a manner that the formatting specifics of similar objects are not taken into account. This is precisely the problem that DocBridge Delta solves, either by displaying the differences visually, or by producing a list of the differences.

Summary

• Comparison of documents or varying formats – particularly for large production jobs
• Visual difference representation down to the pixel level
• Detailed listing of differences at the object level
• Provision of return codes for automatic processing
• Adjustment of the document for comparison in which all the pages are not correctly aligned
• Comparison suppression of specified pages to allow for the processing of documents which for example contain empty pages
• Page areas containing dynamic data such as addresses or the date can be excluded from the comparison
• Checking the consistency of meta information such as indexes in TLE’s in AFP documents
• Available for all commonly used operating systems

Fundamental Technical Process

DocBridge Delta uses the capabilities of the DocBridge Engine to analyze the detailed structure of coded objects in the document files, to convert them to a formatindependent meta format. Since it can process the most common document formats, it is capable of translating even the most varying document formats into a common object structure in the meta format. At the same time DocBridge Delta can compare both input documents and identify the differences object for object.

Typical Usage Scenarios

This makes DocBridge Delta particularly suitable for users of high-volume production jobs who have converted a given document to another format with the help of an application and want to check if the content and its presentation still correspond to the original. The result can be important in terms of quality control, depending on the goal to be achieved with respect to the presentation as well as the object type or resources used internally.

Visual Document Comparison

For the visual comparison, the two documents are rastered at the same resolution, and the resulting pixel pictures are compared – similar to using a light table in which the documents are laid over each other to identify any differences. The file generated in this way shows individual pixels in grey, for those pixels which are the same in both documents, green for those only in the reference document and red for those only in the document being compared to.

This means that even the smallest differences between objects are instantly recognizable, for example edge differences of only a single pixel wide on a slightly differently cut character of a font.

If it is seen that the entire contents of a document being compared are displaced, this can be compensated for using an additional setting, to allow be able to check if apart from this displacement, other differences in the document can be identified.

For the situation where entire pages are not present in one of the documents, a comparison can be suppressed so as to prevent additional empty pages from being compared.

The difference document with the color highlighted comparisons is created as multi-page TIFF document.

Structural Comparison at the Object Level

DocBridge Delta writes a detailed log of the recognized differences of each object on each page to a file. The following types of differences can be seen from the entries in the log file:

• Differing object positioning
• Object content differences such as text or different barcodes
• Varying attributes of the same object type including fonts or font attributes such as font size applied to the same textual content.

Before making the comparison, the two documents are converted to the Unicode- based meta format, so that even for the case where another Codepage has been used, only actual text differences are registered.

Additional Comparison Options

In addition to making a comparison of the presentation of objects between two documents, DocBridge Delta can also perform the following checks:

• Binary compare of two document files
• Checking the difference in size with an optional pre-selected minimum value in bits or pixels (only size differences above a specific value are taken into account)
• Comparison of the number of pages and page orientation
• Comparison based on positioning tolerance (only positioning tolerances above a specific value are taken into account
• The exclusion of selected page areas during the comparison, e.g. for areas of dynamic content such as address fields or dates
• Meta information differences such as varying indexes within TLE’s in an AFP document or XMP information in PDF documents

Attached to all these messages is a return code allowing document comparisons to be evaluated automatically by a program.

Supported Formats

DocBridge Delta can compare documents with the same or different input formats. The following input formats are optionally supported:

Mixed Object Formats

• AFP (incl. AFP line and mixed mode)
• ASCII/EBCDIC linemode
• PCL
• PDF
• SAP GOF (Generic Output Format) with formatted OTF (Output Text Format) and ALF (ABAP list format)
• LCDS (DJDE)
• Metacode (DJDE)
• SVG
• Prescribe (as of the 4th quarter 2006)

Raster Formats

• BMP, GIF, IOCA, JPEG, PCX, PNG, TGA, TIFF

Supported Operating Systems

As with all other Compart products, DocBridge Delta is programmed using an operating system independent library. It has been implemented for the following platforms (additional operating systems available on request):

• Windows 2000, XP and Windows 2003 Server
• GNU/Linux
• Mac OS X
• FreeBSD
• AIX
• Solaris
• HP-UX
• z/OS UNIX system services
• zLinux