[Blindmath] Extracting bitmap images from pdf files

Sat Jan 28 01:51:14 UTC 2012

Prof. Baldwin,

Regarding the price, your comments are correct. If I either had $500 to 
spend or planned to try and convince the commission for the blind to buy me 
something for that much, I would want it fully accessible. I would be buying 
Acrobat for one feature, whereas an IVEO system contains many features I 
might find useful for years to come.

Amanda
----- Original Message ----- 
From: "Richard Baldwin" <baldwin at dickbaldwin.com>
To: "Blind Math list for those interested in mathematics" 
<blindmath at nfbnet.org>
Sent: Friday, January 27, 2012 7:19 PM
Subject: Re: [Blindmath] Extracting bitmap images from pdf files

> Hi Michael,
>
> My comments are embedded in your text below.
>
> On Fri, Jan 27, 2012 at 3:31 PM, Michael Whapples <mwhapples at aim.com> 
> wrote:
>
>> Sorry, I forgot why you want the bitmap files, its to enhance the image
>> further not so it could be used by other embossers.
>>
>
> rgb] Well, actually I want bitmap files for both purposes. My immediate
> need is to help Amanda with the pictures in her physics book. Having said
> that, I also want to be able to enhance the bitmap files for embossing.
> Enhancement would be nice for a Tiger, but is absolutely critical for
> embossers that have no gray scale capability at all, like Amanda's Juliet
> embosser. She and I have developed a program that does a respectable job 
> of
> enhancing images for a Juliet embosser once you get your hands on the
> bitmap file.
>
> rgb] In solving Amanda's problem, I am hopeful that I can develop a
> solution for other blind students as well. This issue not only impacts
> blind math and physics students, it also impacts every blind student using
> college textbooks with inaccessible pictures.
>
>>
>> Is there any image printing drivers? I mean is there anything like those
>> software tools which appear like a printer but output to a PDF, but 
>> instead
>> they output to bitmap or JPG, that would make IVEO do what you want.
>>
>
> rgb] I don't know the answer to that question.
>
>>
>> However again as I mentioned if this was the only use you would put IVEO
>> to, how does it compare on price to the acrobat pro option (providing 
>> that
>> really works as adobe suggest).
>
>
> rgb] I can't speak for Amanda, but I suspect that either option would be
> prohibitively expensive for many blind students.
>
> Thanks for the input.
> Dick Baldwin
>
>>
>>
>> Michael Whapples
>>
>> -----Original Message----- From: Richard Baldwin
>> Sent: Friday, January 27, 2012 6:47 PM
>> To: Blind Math list for those interested in mathematics
>>
>> Subject: Re: [Blindmath] Extracting bitmap images from pdf files
>>
>> Michael wrote " There is one option I am aware of for a blind person to 
>> do
>> this independently, IVEO like John suggested,"
>>
>> I may be wrong, but I didn't get the idea that John's solution will 
>> produce
>> an output bitmap file - only an embossed image.
>>
>> I may be wrong again, but as near as I can tell, IVEO doesn't do any 
>> image
>> enhancement prior to embossing the image. If I am wrong on these points,
>> John will probably come online and set the record straight.
>>
>> IVEO seems to simply convert the bitmap image to gray scale and emboss 
>> the
>> gray scale. While gray scale embossing is okay for some images 
>> (especially
>> blank and white images), it is definitely not the best option for many
>> images. After all, if you convert 16 million colors to four levels of 
>> gray
>> scale, each level of gray scale represents 4 million different colors.
>> Pixels belonging to each set of 4 million colors will not be
>> distinguishable in the gray scale representation.
>>
>> My objective is to gain access to full-color bitmap images so that I can
>> enhance the image for embossing prior to throwing away all of the color
>> information.
>>
>> Embossed versions of bitmap images are often very difficult to 
>> understand,
>> even with a decent description. I believe we need to do everything
>> reasonable to improve the understandability of embossed bitmap images. In
>> some cases, image enhancement techniques at the full-color stage can be
>> used to provide those improvements.
>>
>> So, my quest continues, hopefully without having to pay $445.00 for 
>> Acrobat
>> Pro, just to get access to the images.
>>
>> The fallback position, of course, is to use screen shots and an image
>> editor program to crop out the individual images, but that approach is 
>> not
>> possible for a blind person to use. You can't crop an image out of a 
>> screen
>> shot unless you can see the image.
>>
>> By the way, I don't know how a blind person would carry out the second of
>> the following two steps in John's procedure:
>>
>> * import the PDF into IVEO Creator Pro.
>> * Check the PDF to find which pages have images of interest and emboss
>> those
>> pages.
>>
>> It seems that checking the pdf to find which pages have images would be
>> similar to checking a screen shot of a page to find and crop the image. 
>> It
>> seems that you would need to be able to see the pdf on the IVEO screen to
>> know if it contains an image. I am working with pdf files containing
>> anywhere between 30 and 80 pages. Embossing every page in order to 
>> identify
>> the pages that contain images would not be practical.
>>
>> Dick Baldwin
>>
>> On Fri, Jan 27, 2012 at 11:48 AM, Richard Baldwin
>> <baldwin at dickbaldwin.com>**wrote:
>>
>>  Amanda and others,
>>>
>>> I have contacted Adobe technical support. There solution to the problem 
>>> is
>>> to purchase Acrobat Pro for $445.00. The tech support rep told me that
>>> their program will extract the pictures intact as separate bitmap files.
>>>
>>> Dick Baldwin
>>>
>>>
>>> On Fri, Jan 27, 2012 at 10:44 AM, Michael Whapples <mwhapples at aim.com
>>> >wrote:
>>>
>>>  Hello,
>>>> From what you are describing, my feeling is that the diagrams/images in
>>>> the PDF in question are created from a number of drawing elements 
>>>> rather
>>>> than a single image object. I'm not an expert on PDF, but I think you
>>>> could
>>>> think of it like the difference of a bitmap being a single element (I
>>>> think
>>>> PDF has a way to specify the start of a stream object like a bitmap) 
>>>> and
>>>> an
>>>> SVG being formed from lots of elements like lines and shapes (I think 
>>>> in
>>>> PDF the lines and such like can be created with basic PDF drawing
>>>> facilities so are not in a separate object). When the image is formed
>>>> from
>>>> lots of elements then it may be hard for the software to know what 
>>>> makes
>>>> up
>>>> a given diagram in the book/document, it just lays it out as specified
>>>> and
>>>> you work out what's related. I think one way to tell whether you have
>>>> this
>>>> sort of image is to see if NVDA will read some of the text labels of 
>>>> the
>>>> image, if it does then its not a pure bitmap (you probably could use 
>>>> the
>>>> read out lout function of adobe reader as well). Therefore I imagine 
>>>> that
>>>> without clever recognition algorithms you are unlikely to get something
>>>> which will extract it as you want.
>>>>
>>>> There is one option I am aware of for a blind person to do this
>>>> independently, IVEO like John suggested, however IVEO isn't a cheap
>>>> option
>>>> and depending on how much is to be done would determine whether its 
>>>> worth
>>>> the money if providing accessible diagrams from PDF was its only use.
>>>> IVEO
>>>> does not require a tiger printer, swell paper would work, other 
>>>> embossers
>>>> may (the outputting from IVEO is the question as I think it may only
>>>> output
>>>> to devices appearing as standard printers). Interesting, the IVEO route
>>>> again is requiring a human to make the decision on what forms the
>>>> diagram.
>>>>
>>>> Michael Whapples
>>>>
>>>> -----Original Message----- From: Richard Baldwin
>>>> Sent: Friday, January 27, 2012 3:28 PM
>>>> To: Jamal Mazrui
>>>> Cc: Blind Math list for those interested in mathematics
>>>> Subject: Re: [Blindmath] Extracting bitmap images from pdf files
>>>>
>>>>
>>>> Hi Jamal,
>>>>
>>>> It is a great program, easy to use, and probably totally accessible. I
>>>> particularly like the fact that the program doesn't require a windows
>>>> installation. The output data is well organized and including the page
>>>> numbers in the bmp file names is a great help in analyzing them.
>>>>
>>>> Unfortunately, the output produced by the program suffers from the same
>>>> issues that I have encountered with all of the other image extractor
>>>> programs that I have tried. A few of the images come out intact. Most 
>>>> of
>>>> the images don't come out intact.
>>>>
>>>> For example, page three of one of the pdf files that I tested has a
>>>> single
>>>> image of a battery. It is the same image that I enhanced and posted in 
>>>> an
>>>> earlier post. Your program produced 54 bmp files for that page. A few 
>>>> of
>>>> them were icons such as arrows exclamation marks, etc. The remaining 
>>>> bmp
>>>> files appear to be a very small pieces of the image of the battery. By
>>>> the
>>>> way, I got the earlier image of the battery by taking a screen shot of
>>>> the
>>>> page and using an image editing program to crop out the battery image.
>>>> None
>>>> of the image extraction programs that I have tested extract the image
>>>> intact.
>>>>
>>>> I don't know anything at all about the internal structure of pdf files,
>>>> and
>>>> this behavior of breaking an image into many small pieces may depend on
>>>> how
>>>> the file is constructed in the first place. In any event, my immediate
>>>> problem has to do with a specific set of pdf files that are the 
>>>> chapters
>>>> from a specific physics book, so this program doesn't solve my problem.
>>>>
>>>> Thanks for offering the program.
>>>> Dick Baldwin
>>>>
>>>> On Fri, Jan 27, 2012 at 5:18 AM, Jamal Mazrui <empower at smart.net> 
>>>> wrote:
>>>>
>>>>  In an attempt to facilitate a free, non-web dependent solution, I have
>>>>
>>>>> written a Windows console-mode utility called PDF2Images, built with
>>>>> PowerBASIC and a PDF library.  The distribution archive, including
>>>>> documentation and source code, is available at
>>>>>
>>>>> http://empowermentzone.com/******pdf2images.zip<http://empowermentzone.com/****pdf2images.zip>
>>>>> <http://**empowermentzone.com/****pdf2images.zip<http://empowermentzone.com/**pdf2images.zip>
>>>>> >
>>>>> <http://**empowermentzone.com/****pdf2images.zip<http://empowermentzone.com/**pdf2images.zip>
>>>>> <http://**empowermentzone.com/**pdf2images.zip<http://empowermentzone.com/pdf2images.zip>
>>>>> >
>>>>>
>>>>> >
>>>>>
>>>>>
>>>>> I am interested in any feedback on how well it works compared to other
>>>>> approaches.
>>>>>
>>>>> Jamal
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>> --
>>>> 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/<http://www.austincc.edu/**baldwin/><
>>>> http://www.austincc.edu/**baldwin/ <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/ <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/ <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/
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