Prerequisites
Software
UNIX shell, e.g. Windows Subsystem for Linux with Ubuntu (tested with WSL/Ubuntu 22.04 LTS and Debian 11 on the tape server)
Tesseract OCR (tested with version 4.1.x)
muPDF tools (tested with version 1.17)
GhostScript (tested with version 9.53)
Make sure the versions of tesseract, muPDF and GhostScript are up to date. Run the following command on your command line to update software components of your Linux installation:
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Doesn't work as described here, still missing instructions to place the PDF/A instructions and ICC profile files: https://ghostscript.readthedocs.io/en/latest/VectorDevices.html#creating-a-pdf-a-document The path under step 4 (using Ghostscript) needs to be valid for the OS/computer from which you are running the command. The PS file the path points to needs to be edited to contain a valid path pointing to an ICC profile. |
Navigate to the staging directory containing the Production Master (_pm) image files
Create temporary subdirectories 'pdf' and 'pdf/pages', and navigate back to the staging directory:
Code Block language bash mkdir pdf cd pdf mkdir pages cd ..Run tesseract OCR on all images in the staging directory:
Code Block language bash for i in *.tif; do tesseract -c tessedit_page_number=0 -l eng $i pdf/pages/${i%_pm.tif} pdf; doneMerge page-level PDF documents into one PDF per volume/issue:
Code Block language bash mutool merge -o pdf/combined-pdf.pdf pdf/pages/*.pdfProduce the final PDF document.
Code Block language bash gs -sDEVICE=pdfwrite \ -dPDFA=2 \ -dPDFACompatibilityPolicy=1 \ -dNOSAFER \ -dFastWebView \ -sColorConversionStrategy=RGB \ -dDownsampleColorImages=true \ -dColorImageDownsampleThreshold=1.0 \ -dAutoRotatePages=/None \ -dColorImageResolution=150 -o downsampled-pdf.pdf /mnt/dps/staff_workspaces/mirko/pdfa/PDFA_def_UTL.ps combined-pdf.pdfDelete the pdf subfolder and combined-pdf.pdf