Multicrop - how to leave more room around image edges?

A plethora of command-line scripts that perform geometric transforms, blurs, sharpens, edging, noise removal, and color manipulations.
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ewb
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Multicrop - how to leave more room around image edges?

Post by ewb » 2015-12-05T13:38:54-07:00

I have been experimenting with the Multicrop script to use as part of an upcoming digitization project. The script works beautifully on our images. I would, however, like to have the resulting image have a crop that is less tight - and am wondering if someone could please suggest how to achieve this?

I am currently running the following:

Code: Select all

./multicrop.sh -f 20 -u 1 crop-please.jpg cropped.jpg
on images such as this one:
https://www.dropbox.com/s/tvdgbr6ebvar3 ... e.jpg?dl=0

with the follow result - which is lovely - but would be even lovelier if there were more pixels around each side of the image...

https://www.dropbox.com/s/2umq614p4c06m ... 1.jpg?dl=0

I am new to using Fred's ImageMagick Scripts - which are impressive - and look forward to learning more about the details of their use.

Thanks,
Eric

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fmw42
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Re: Multicrop - how to leave more room around image edges?

Post by fmw42 » 2015-12-05T14:45:40-07:00

You can try to decrease the -f value. But that may not do too much. Alternately, just add a white border to your images using -bordercolor white -border X. See http://www.imagemagick.org/Usage/crop/#border. The script does not really have any way to increase the crop size, since it uses IM -fuzz XX% (-f argument) and -trim. A new argument could be added to add padding (border) to each output. But right now that is not included. More information about your situation and why you want less crop would be needed for me to understand the motivation before I would add a new argument for padding.

You may reply here or send my PM on this forum or contact me offline at (fmw at alink dot net)

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Re: Multicrop - how to leave more room around image edges?

Post by ewb » 2015-12-05T16:12:31-07:00

Thank you. We have experimented with the -f value and were not able to achieve the desired result.

We are interested in less crop in order to be in sync with U.S. National Archives and Records Administration (NARA), Library of Congress (LOC) and World Digital Library (WDL) cropping guidelines - which we understand to require that we crop beyond the edge of the original object and to leave enough of the scanner bed showing such that researchers can clearly discern that the entire object was scanned. I think that the Multicrop script's cropping level may meet the "technical" definition of what we are trying to achieve - but our initial sense is that the crops are quite a bit tighter than what we have been doing traditionally - and what we see being done by other digital library projects. More research on this question may be required on our part - but suspect that there is a wider crop option - or related strategy - with this script will be very helpful.

As for adding a border color - our sense is that this would not satisfy the digitization guidelines. Again, this is our sense and has not (yet) included sufficient research and investigation.

Here, for instance, are a couple of quotes from the LOC and WDL documentation:
Cropping for Pictorial Materials. The Library wishes to provide researchers with a reproduction of the entire original item. Thus, images shall be framed and cropped to show the entire original item and beyond the item(s) edges. ... from The Library of Congress Technical Standards for Digital Conversion Of Text and Graphic Materials
and
Cropping of bound and manuscript materials. The Library requires presentation of the entire
original sheet or page. In no event shall the actual document be cropped. Researchers using
Library of Congress digital documents often wish to be reassured that the entire document has
been captured. This is especially desirable for unbound manuscript documents. A "border zone"
approximately 1/4-inch or less of the surface behind the scanned document shall be provided
whenever possible. ... from The Library of Congress Technical Standards for Digital Conversion Of Text and Graphic Materials
Thanks very much for your assistance and please let me know if I can provide additional information regarding our request for assistance.

Regards,
Eric

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fmw42
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Re: Multicrop - how to leave more room around image edges?

Post by fmw42 » 2015-12-06T16:44:31-07:00

OK. I have modified the script and uploaded the new version that will allow you to crop a bit larger all around each image, but only when used with -u (unrotate) 1 or 3.

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Re: Multicrop - how to leave more room around image edges?

Post by ewb » 2015-12-07T09:05:18-07:00

Thank you - the modified script is working perfectly and having the ability to adjust the crop "tightness" via the -e value is fantastic.

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Re: Multicrop - how to leave more room around image edges?

Post by fmw42 » 2015-12-07T19:13:28-07:00

A "border zone"
approximately 1/4-inch or less of the surface behind the scanned document shall be provided
whenever possible.
It says 1/4 inch or less? So what value are you using? In pixels at 72 dpi, 1/4 in would be 18 pixels.

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Re: Multicrop - how to leave more room around image edges?

Post by ewb » 2015-12-07T19:34:02-07:00

The following has been working well:

Code: Select all

./multicrop.sh -f 20 -u 1 -e 18 crop-please.jpg crop-e18.jpg
...and produces the following result:

https://www.dropbox.com/s/nf8wurog0ctwf ... 1.jpg?dl=0

For reference, this is based on this image:

https://www.dropbox.com/s/tvdgbr6ebvar3 ... e.jpg?dl=0

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