Math formulas conversion help

Sciamano · 03-25-2011, 03:49 PM

Hi!
I'm trying to convert a PDF about Fermat's last theorem ("no three positive integers a, b, and c can satisfy the equation a^n + b^n = c^n for any integer value of n greater than two")

The problem is that the MOBI converted file loses most of the mathematical format. All exponents will become "normal" numbers and letters.
For example, in the converted file the above equation gets written as:

an + bn = cn

You can imagine it's impossible to read a mathematical text where the mathematical parts are not correctly formatted.

Any ideas?

Thanks

kovidgoyal · 03-25-2011, 04:01 PM

The problem is that you are trying to convert a PDF. There is no way to get mathematical formulas from a PDF into another format. If you have the document in some other format I would recommend you use that.

Sciamano · 03-25-2011, 04:03 PM

Unfortunately I only have a PDF.

So there is no solution at all?

(Thanks for the great software, by the way, Kovid!)

kovidgoyal · 03-25-2011, 04:05 PM

You're welcome and no I know of no way to convert math formulae in a PDF. You can try various PDF cropping/resizing, PDF to image tools that might make your original PDF readable on the Kindle, but converting is not likely to happen.

WillAdams · 03-25-2011, 04:17 PM

Marcel Weiher's TextLightning.app will attempt to convert positional information in a .pdf into text formatting and write out an .rtf --- it works surprisingly well, but not perfectly due to the difficulty of the task.

William

theducks · 03-25-2011, 04:23 PM

Quote:

Originally Posted by WillAdams

Marcel Weiher's TextLightning.app will attempt to convert positional information in a .pdf into text formatting and write out an .rtf --- it works surprisingly well, but not perfectly due to the difficulty of the task.

William

You do realize that Dr. Knuth wrote TEX (and MetaFont) because he was tired of his Math textbooks being mangled ?

Sciamano · 03-25-2011, 05:42 PM

Thanks William, I'll try to convert to rtf with that app you talked about. Maybe it works.
I'll let you know.

Thanks everyone.

[edit]
Scratch that... just found out it's for Mac. I have no access to any Mac unfortunately.

WillAdams · 03-31-2011, 08:16 AM

theducks, yes, I know about TeX, but Dr. Knuth wasn't working from .pdf originals, so I don't see why mentioning it here now is useful. FWIW, I have one of his (physical) reward checks and have published papers in TUGboat and edited the 2003 proceedings issue.

If the OP had access to the original source instead of the .pdf, this discussion would be different.

Sciamano, I believe Marcel has ported TextLightning to Windows and Linux using GNUstep --- you should contact him to see.

William

Sciamano · 03-31-2011, 10:43 AM

Thanks Will. I tried googling for the windows version but couldn't find anything.
I've contacted Marcel, will let you know what he says.

Kindle3fan · 04-01-2011, 05:34 PM

Question: Is there an app that can convert the formulas into embedded images and the whole document- into a supported format so that we can easily turn it into mobi with the Calibre?

EnQ · 06-22-2011, 06:33 AM

I just got my Kindle last week and reading mathematic and lecture PDFs from university on it was the main reason for buying it. Although I'm okay with how it works (though there could be more options to pan, zoom and navigate, especially if a drawing is divided across the 3 zoom areas you get in landscape mode), I also tried to convert a few of those PDFs with Calibre to .mobi out of curiosity.

It's not only math formulas but also drawings that get misconverted. My idea is to improve heuristics to optionally detect drawings and render them to images instead and do the same for any formulas. Detecting formulas in LaTeX-generated PDFs could work quite well based on a recognition of the embedded fonts being used (simply by their embedded name?). Drawings could be detected by image recognition (render PDF page or paragraphs from it to image, run detection algorithm on that image to tell drawings/images from text and then decide how to convert it). It would of course be very slow but since you would convert a book only once, that should be okay. I'm sure a detection algorithm for text vs. graphics already exists in many implementations (OCR or OpenCV).

I'm not sure if anyone attempted to implement a detection/heuristic like that already. If I had some more spare time at the moment I would take a look at it; unfortunately I'm currently too busy, so I don't think I may come up with improvements any time soon. If anyone started/starts doing something like that, I'd be glad to know about it (maybe drop me a PM).

03-25-2011, 03:49 PM	#1
Sciamano Member Posts: 23 Karma: 10 Join Date: Mar 2011 Device: Kindle 3	Math formulas conversion help Hi! I'm trying to convert a PDF about Fermat's last theorem ("no three positive integers a, b, and c can satisfy the equation a^n + b^n = c^n for any integer value of n greater than two") The problem is that the MOBI converted file loses most of the mathematical format. All exponents will become "normal" numbers and letters. For example, in the converted file the above equation gets written as: an + bn = cn You can imagine it's impossible to read a mathematical text where the mathematical parts are not correctly formatted. Any ideas? Thanks

04-01-2011, 05:34 PM	#10
Kindle3fan Junior Member Posts: 1 Karma: 10 Join Date: Apr 2011 Device: Kindle 3	Question: Is there an app that can convert the formulas into embedded images and the whole document- into a supported format so that we can easily turn it into mobi with the Calibre? Last edited by Kindle3fan; 04-01-2011 at 05:46 PM.

06-22-2011, 06:33 AM	#11
EnQ Junior Member Posts: 1 Karma: 10 Join Date: Jun 2011 Device: Kindle 3	I just got my Kindle last week and reading mathematic and lecture PDFs from university on it was the main reason for buying it. Although I'm okay with how it works (though there could be more options to pan, zoom and navigate, especially if a drawing is divided across the 3 zoom areas you get in landscape mode), I also tried to convert a few of those PDFs with Calibre to .mobi out of curiosity. It's not only math formulas but also drawings that get misconverted. My idea is to improve heuristics to optionally detect drawings and render them to images instead and do the same for any formulas. Detecting formulas in LaTeX-generated PDFs could work quite well based on a recognition of the embedded fonts being used (simply by their embedded name?). Drawings could be detected by image recognition (render PDF page or paragraphs from it to image, run detection algorithm on that image to tell drawings/images from text and then decide how to convert it). It would of course be very slow but since you would convert a book only once, that should be okay. I'm sure a detection algorithm for text vs. graphics already exists in many implementations (OCR or OpenCV). I'm not sure if anyone attempted to implement a detection/heuristic like that already. If I had some more spare time at the moment I would take a look at it; unfortunately I'm currently too busy, so I don't think I may come up with improvements any time soon. If anyone started/starts doing something like that, I'd be glad to know about it (maybe drop me a PM). Last edited by EnQ; 06-22-2011 at 06:38 AM.

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03-25-2011, 04:01 PM	#2
kovidgoyal creator of calibre Posts: 43,858 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	The problem is that you are trying to convert a PDF. There is no way to get mathematical formulas from a PDF into another format. If you have the document in some other format I would recommend you use that.

03-25-2011, 04:03 PM	#3
Sciamano Member Posts: 23 Karma: 10 Join Date: Mar 2011 Device: Kindle 3	Unfortunately I only have a PDF. So there is no solution at all? (Thanks for the great software, by the way, Kovid!)

03-25-2011, 04:05 PM	#4
kovidgoyal creator of calibre Posts: 43,858 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	You're welcome and no I know of no way to convert math formulae in a PDF. You can try various PDF cropping/resizing, PDF to image tools that might make your original PDF readable on the Kindle, but converting is not likely to happen.

03-25-2011, 04:17 PM	#5
WillAdams Wizard Posts: 1,234 Karma: 3350652 Join Date: Feb 2008 Device: Amazon Kindle Paperwhite (300ppi), Samsung Galaxy Book 12	Marcel Weiher's TextLightning.app will attempt to convert positional information in a .pdf into text formatting and write out an .rtf --- it works surprisingly well, but not perfectly due to the difficulty of the task. William

03-25-2011, 05:42 PM	#7
Sciamano Member Posts: 23 Karma: 10 Join Date: Mar 2011 Device: Kindle 3	Thanks William, I'll try to convert to rtf with that app you talked about. Maybe it works. I'll let you know. Thanks everyone. [edit] Scratch that... just found out it's for Mac. I have no access to any Mac unfortunately.

03-31-2011, 08:16 AM	#8
WillAdams Wizard Posts: 1,234 Karma: 3350652 Join Date: Feb 2008 Device: Amazon Kindle Paperwhite (300ppi), Samsung Galaxy Book 12	theducks, yes, I know about TeX, but Dr. Knuth wasn't working from .pdf originals, so I don't see why mentioning it here now is useful. FWIW, I have one of his (physical) reward checks and have published papers in TUGboat and edited the 2003 proceedings issue. If the OP had access to the original source instead of the .pdf, this discussion would be different. Sciamano, I believe Marcel has ported TextLightning to Windows and Linux using GNUstep --- you should contact him to see. William

03-31-2011, 10:43 AM	#9
Sciamano Member Posts: 23 Karma: 10 Join Date: Mar 2011 Device: Kindle 3	Thanks Will. I tried googling for the windows version but couldn't find anything. I've contacted Marcel, will let you know what he says.