Scanned piano sheets enhancement
Posted: 2019-03-21T11:51:54-07:00
Hello dear image processing community 
I have a little challenge for you : I have a lot of scanned piano sheet.
As you could guess, books are not very practical when playing piano. (doesn't stay open damn 200 pages book !)
That's why scanning is very important because it allows to use the sheets with a Windows Surface or an iPad directly or reprint them on single pages.
Anyway, the problem is the readability of such scans.
I have tons of scans that looks like that :
Bright scan
Dark scan
So, I'm trying to batch process all the scan that I have in order to improve them (and pack them into pdfs but that's another story and I'm okay with this part).
In order to achieve that, I need a single script that would be able to improve any music sheet.
So far, I tried some command that I found here and there but with no real improvement.
I was thinking about doing those steps :
1) auto-level in order to accentuate the difference between bright and dark part of the document
2) make the 60% brightest pixels white (because they should represent the background)
3) make the 10% darkest pixels black (because they should represent the music notation)
4) make the 30% remaining pixels from white to black (because the should represent the blur effect that makes the sheet readable)
But I don't know how to do that or if it would work. I think the steps 2), 3) and 4) could be done with Sigmoidal Non-linearity Contrast but I must admit that I am lost.
Do you know how I could achieve what I want ? Is my approach valid ? Is there another way to get the results I would like ?
Thank you very much for your help. I'll keep you inform if I find something interesting
I have a little challenge for you : I have a lot of scanned piano sheet.
As you could guess, books are not very practical when playing piano. (doesn't stay open damn 200 pages book !)
That's why scanning is very important because it allows to use the sheets with a Windows Surface or an iPad directly or reprint them on single pages.
Anyway, the problem is the readability of such scans.
I have tons of scans that looks like that :
Bright scan
Dark scan
So, I'm trying to batch process all the scan that I have in order to improve them (and pack them into pdfs but that's another story and I'm okay with this part).
In order to achieve that, I need a single script that would be able to improve any music sheet.
So far, I tried some command that I found here and there but with no real improvement.
Code: Select all
convert in.jpg -negate -lat 50x50+1% -negate out1.jpg
convert in.jpg out2.jpg
mogrify -normalize out2.jpg
convert in.jpg -auto-level out3.jpg
convert in.jpg -despeckle -despeckle out4.jpg
1) auto-level in order to accentuate the difference between bright and dark part of the document
2) make the 60% brightest pixels white (because they should represent the background)
3) make the 10% darkest pixels black (because they should represent the music notation)
4) make the 30% remaining pixels from white to black (because the should represent the blur effect that makes the sheet readable)
But I don't know how to do that or if it would work. I think the steps 2), 3) and 4) could be done with Sigmoidal Non-linearity Contrast but I must admit that I am lost.
Do you know how I could achieve what I want ? Is my approach valid ? Is there another way to get the results I would like ?
Thank you very much for your help. I'll keep you inform if I find something interesting