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Batch Converting/Standardizing Multiple Mixed Resolution Images
Posted: 2015-06-07T02:03:22-07:00
by thatoldfool
Good afternoon,
Situation:
I'm repairing a poorly scanned PDF in ScanTailor. Whoever scanned the book scanned over 3 separate sessions using at least 2 different DPI's.
Problem:
Mixed resolutions mean that page sizes appear to vary. I need to somehow batch convert a directory of images to a standard resolution and size.
Help me ImageMagick, you're my only hope!
Thanks in advance!
-tof
Re: Batch Converting/Standardizing Multiple Mixed Resolution Images
Posted: 2015-06-07T03:07:07-07:00
by snibgo
I suppose each PDF page contains exactly one image?
Others here have more expertise at PDF than me, but I would try:
Code: Select all
convert -density XX in.pdf out.pdf
Choose XX to be the greatest scanning density used.
It may be better to do the job in stages:
1. Extract all the pages with pdfimages.
2. Resample as required to make them all the same dpi.
Code: Select all
convert page-0123.tiff -resample 300 out-page-0123.tiff
With luck, all the pages are now the same density and size (in pixels and inches). If they are not quite the same size, also use "-extent":
Code: Select all
convert page-0123.tiff -resample 300 -extent WWxHH out-page-0123.tiff
where WW and HH are the maximums.
3. Reassemble the PDF:
Re: Batch Converting/Standardizing Multiple Mixed Resolution Images
Posted: 2015-06-07T03:54:38-07:00
by thatoldfool
snibgo,
Bam, I combined your suggestions with a few others I read about here on the forum and my goal was achieved. Steps:
1. Export PDF to images
2. mogrify -path ~/Desktop/test/converted/ -format jpg -resample 300 -resize 3508x2480 *.jpg
resample on its own didn't do the trick for some reason.
Thanks for the suggestion! What an amazing programme...
-tof