djatoka-devel

[djatoka-devel] image distortion when rotating images using OpenURL service

[Shaun E. <sh...@pr...>]

Hi folks,
Perhaps someone can help me with this.  I'm getting some strange results 
when trying to rotate an image using the Djatoka OpenURL service.  Using 
the links below, one will notice that the document text is distorted and 
illegible when rotated 90 degrees. (180 degree rotation is fine, but 270 
is also screwed up.)

Normal:
http://findingaidsdev.princeton.edu/images/adore-djatoka/resolver?url_ver=Z39.88-2004&rft_id=urn:pudl:images:deliverable:AC044/c0003/00000001.jp2&svc_id=info:lanl-repo/svc/getRegion&svc_val_fmt=info:ofi/fmt:kev:mtx:jpeg2000&svc.format=image/jpeg&svc.level=5&svc.rotate=0&mimetype=image.jpg

Rotated 90 degrees:
http://findingaidsdev.princeton.edu/images/adore-djatoka/resolver?url_ver=Z39.88-2004&rft_id=urn:pudl:images:deliverable:AC044/c0003/00000001.jp2&svc_id=info:lanl-repo/svc/getRegion&svc_val_fmt=info:ofi/fmt:kev:mtx:jpeg2000&svc.format=image/jpeg&svc.level=5&svc.rotate=90&mimetype=image.jpg

I don't know if this matters, but this image was extracted from a PDF as 
a bitmap, converted to a TIFF and then compressed to JPEG2000 using the 
same compression "recipe" as we are for images produced in our photo 
studio (which rotate just fine). When rotating the JPEG2000 images in 
ImageMagick, the text is perfectly legible.

Any thoughts?

-- 
Shaun D. Ellis
Digital Library Interface Developer
Firestone Library, Princeton University
voice: 609.258.1698 | sh...@pr...

[djatoka-devel] Resolved: image distortion when rotating images using OpenURL service

[Shaun E. <sh...@pr...>]

Hi folks,
I just wanted to follow up on this since it has been resolved, and may 
help someone else.

To get rid of the image distortion, we discovered that we had to convert 
the original TIFF files to 24-bit RGB (as opposed to 8-bit grayscale) 
before compressing them with Kakadu.

That mostly worked, but when we requested certain "levels" we would 
sometimes end up with a 1x1 pixel image.  After setting a compression 
rate for each layer we were creating, it now works as expected.

Here's our Kakadu recipe for the curious:

$KDU_COMPRESS -i $tiff \
                -o $jp2_name \
                Clevels=6 \
                Clayers=4 \
                Cuse_precincts=yes \
                Cprecincts=\{256,256\} \
                Cblk=\{64,64\} \
                Corder=RPCL \
                ORGgen_plt=yes \
                ORGtparts=R \
                Stiles=\{256,256\} \
                -rate 0.80,1.2,2.4,4.8 \
                -jp2_space sRGB \ # parameter omitted for 8-bit
                -double_buffering 10 \
                -num_threads 4 \
                -no_weights \
                -quiet


Regards,
Shaun Ellis

>>> On 05/03/2012 04:33 PM, Shaun Ellis wrote:
>>>> Hi folks,
>>>> Perhaps someone can help me with this. I'm getting some strange results
>>>> when trying to rotate an image using the Djatoka OpenURL service. Using
>>>> the links below, one will notice that the document text is distorted
>>>> and
>>>> illegible when rotated 90 degrees. (180 degree rotation is fine, but
>>>> 270
>>>> is also screwed up.)
>>>>
>>>> Normal:
>>>> http://findingaidsdev.princeton.edu/images/adore-djatoka/resolver?url_ver=Z39.88-2004&rft_id=urn:pudl:images:deliverable:AC044/c0003/00000001.jp2&svc_id=info:lanl-repo/svc/getRegion&svc_val_fmt=info:ofi/fmt:kev:mtx:jpeg2000&svc.format=image/jpeg&svc.level=5&svc.rotate=0&mimetype=image.jpg
>>>>
>>>>
>>>>
>>>> Rotated 90 degrees:
>>>> http://findingaidsdev.princeton.edu/images/adore-djatoka/resolver?url_ver=Z39.88-2004&rft_id=urn:pudl:images:deliverable:AC044/c0003/00000001.jp2&svc_id=info:lanl-repo/svc/getRegion&svc_val_fmt=info:ofi/fmt:kev:mtx:jpeg2000&svc.format=image/jpeg&svc.level=5&svc.rotate=90&mimetype=image.jpg
>>>>
>>>>
>>>>
>>>> I don't know if this matters, but this image was extracted from a
>>>> PDF as
>>>> a bitmap, converted to a TIFF and then compressed to JPEG2000 using the
>>>> same compression "recipe" as we are for images produced in our photo
>>>> studio (which rotate just fine). When rotating the JPEG2000 images in
>>>> ImageMagick, the text is perfectly legible.
>>>>
>>>> Any thoughts?
>>>>
>>

-- 
Shaun D. Ellis
Digital Library Interface Developer
Firestone Library, Princeton University
voice: 609.258.1698 | sh...@pr...