[Blindmath] Extracting bitmap images from pdf files

Wed Jan 25 19:39:03 UTC 2012

Alan,

I don't know if this will answer your question or not, but I will give it a
try.

Very soon, Amanda and I will publish a new free program that takes bitmap
files as input, enhances them for embossing, and writes the enhanced image
out into a filename.sig formatted output file.

If your dux software and your embosser can use sig files as input, it may
be just the right thing for you.

And if you haven't already guessed, my reason for needing a good clean way
to extract bitmap files from pdf files is so that Amanda can extract,
enhance, and emboss the images from the pdf files for her physics textbook
on her Juliet embosser.

Unfortunately, she doesn't have access to an IVEO system or a Tiger.

Along that line, very soon, I will probably publish a new free program that
takes bitmap files as input, enhances them for embossing, and writes the
enhanced image out into an svg file that can be opened in IE9 and printed
on a Tiger with or without preserving three or four shades of gray. That
software is currently being evaluated by a couple of blind technical
individuals who frequent the blind math list. Right now, I am waiting on
the results of that evaluation to decide if the enhancement algorithm
provides enough benefits to make it worth the effort to clean up a couple
of accessibility issues and get it ready for publication.

Dick Baldwin

On Wed, Jan 25, 2012 at 1:24 PM, Richard Baldwin <baldwin at dickbaldwin.com>wrote:

> Sina,
>
> I have tried the pdf to html image harvesting trick with several onsite
> converters. Dozens of websites claim to offer the conversion service. Of
> the four or five that I tried, only one seemed to do the job and as I
> recall, it was limited to 2-mbyte pdf files, which is a problem. Also, on
> that one, whenever I harvested the image from the html page, I got a large
> blank image with a small image somewhere on it. Although I can crop the
> small image from the large blank image, sight is required to pull that off.
>
>  Do you have a favorite way to convert pdf files to html files?
>
> Thanks,
> Dick Baldwin
>
>
> On Wed, Jan 25, 2012 at 12:33 PM, John Gardner <john.gardner at orst.edu>wrote:
>
>> Dick, if someone is fortunate enough to have a ViewPlus embosser and IVEO
>> Creator Pro, she can have pretty good access to images.
>> * import the PDF into IVEO Creator Pro.
>> * Check the PDF to find which pages have images of interest and emboss
>> those
>> pages.
>> * Put the embossed page on the touchpad and "Zoom Rectangle" by clicking
>> on
>> diagonally-opposite corners of the image of interest.  This will zoom that
>> image to occupy maximum size the page will permit.
>> * Emboss the zoomed image and read it using the touchpad.  Horizontal text
>> on the image should read when pressed.  The OCR in Creator Pro works
>> really
>> well with PDF's so if the resolution is at all decent, the text usually is
>> OCRed well.
>> * Go back to the original image and do same for any other image on that
>> page.  Repeat for images on other pages.
>>
>> Note that a sighted person can skip the first embossing step and just zoom
>> those images.  Handy to have sighted people around, but if there aren't it
>> just takes a little longer.  By the way, that sighted person can create
>> overlays on important objects on the graphic and label them to improve
>> accessibility even more.
>>
>> John
>>
>> -----Original Message-----
>> From: blindmath-bounces at nfbnet.org [mailto:blindmath-bounces at nfbnet.org]
>> On
>> Behalf Of Richard Baldwin
>> Sent: Wednesday, January 25, 2012 10:08 AM
>> To: BlindMath Mailing List; accessibleimage at freelists.org
>> Subject: [Blindmath] Extracting bitmap images from pdf files
>>
>> Many blind students receive electronic textbooks in pdf format.
>>
>> Many textbooks contain lots of images.
>>
>> Many images are poorly described in textbooks.
>>
>> Various ways to convert bitmap images into tactile images are available --
>> some fairly good, some not so good, some very poor. However, regardless of
>> the quality of the conversion to tactile format, you must have the
>> original
>> image file in order to get anything.
>>
>> I have tried four or five different online file conversion sites in an
>> attempt to find a clean way that a blind student can extract the images
>> from a pdf textbook file without success. Different sites have different
>> problems, but they all seem to have some kind of problems that make it
>> very
>> difficult to extract the images from pdf files.
>>
>> Has anyone identified an online site or downloadable program that is
>> available either free or at a reasonable price to cleanly extract the
>> images from pdf files, which often range up to 10 or more megabytes  or
>> more in size?
>>
>> Thanks,
>> Dick Baldwin
>>
>> --
>> Richard G. Baldwin (Dick Baldwin)
>> Home of Baldwin's on-line Java Tutorials
>> http://www.DickBaldwin.com
>>
>> Professor of Computer Information Technology
>> Austin Community College
>> (512) 223-4758
>> mailto:Baldwin at DickBaldwin.com
>> http://www.austincc.edu/baldwin/
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>
>
>
> --
> Richard G. Baldwin (Dick Baldwin)
> Home of Baldwin's on-line Java Tutorials
> http://www.DickBaldwin.com
>
> Professor of Computer Information Technology
> Austin Community College
> (512) 223-4758
> mailto:Baldwin at DickBaldwin.com
> http://www.austincc.edu/baldwin/
>

-- 
Richard G. Baldwin (Dick Baldwin)
Home of Baldwin's on-line Java Tutorials
http://www.DickBaldwin.com

Professor of Computer Information Technology
Austin Community College
(512) 223-4758
mailto:Baldwin at DickBaldwin.com
http://www.austincc.edu/baldwin/