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Create a low cost custom scan box #73
We need to create a low cost custom scan box, so that we can scan books easily.
the existing scanners are costly.
CZUR ET 16 Plus Smart Book Scanner - 56,000 INR
Instead of this, make a scanbox like
Created the above box.
Size = 1.5 x 1.5 x 1.5 feet
Expenses so far - plywood, carpenter charge - 2100
Expected cost - 3000 Rs
With this, anyone can scan a book with a normal digital camera or mobile phone.
Once we did this, we can add more improvements for the next scan boxes.
Srini check Kalyan recommendations
Have to fit the lights on the side walls and fit white sheets in between.
Install Scantailor and tesseract
split a pdf to multiple images using ghostscript
Do ocr using tesseract
@tshrinivasan Thanks for the post, the scanner box is super impressive.
I am interested in the software process. One problem which has been plaguing scanning of old Tamil books to PDF has been, the inability to select, copy n paste intelligible Tamil text (Unicode) from the PDF pages to say MS Word or Notepad. For this to work, I guessed we need to have an OCR to generate Tamil text somewhere in the pipeline and then embed the text back to the PDF.
In this context, recently I found all the books in Singapore's NLB Tamil collection, supporting seamless (extremely low error) copy n paste of Tamil text out from PDF. I have been researching how they are doing - I experimented with a python script to use Google Vision OCR to get something working after I saved all pages in a PDF as images. That's where I got stuck, unable to proceed further in the workflow.
Now, seeing the tweet today, I was pleasantly surprised, you have solved the problem. I have two queries:
Lastly, can you write a detailed blog post on the steps outside this GitHub thread, as it will benefit a wider set of people (especially non-programmers) who wish to scan and support Copy N Paste for old Tamil books.
Once again, many thanks for your effort and sharing them.
Initially, I thought that we do all the scan, fix images, improve images, convert to PDF using mobile itself.
Adobe scan, cam scanner kind of apps do this.
But, the results are not impressive.
Did a test with ScanTailor. It is the magician and King in this field.
Raw scan output
Result from Adobe scan mobile app
See the difference of contrast across the page due to light reflection over the glass. They are not good for printing and OCRing.
But Found scantailor improves the image quality to a very high level.
This is perfect for print or OCR.
Few inputs from bharat varma in twitter
Hinge glass at the far edge to ease book placement.
Cut panels on the side & put white acrylic sheets for light diffusion. Keep lights outside.
If using a camera, use a CPL filter to cut glare.
Use a long lens and an inclined base, and you can probably shoot two books at once.
you can add a CPL filter to a Point and shoot camera..
A filter thread on the lens itself, an add on accessory tube that attaches to the body with a threaded receptacle at the end & a similar small tube that can be stuck to the front of the tube housing the lens.
Does this section work? :)
The inclined lines are the base & the book.
"O" is camera with a long focal length (less distortion, edge to edge sharpness).
o o is direction.
The camera needs to be parallel to the book. Keeping it at a distance with a longer focal length makes it more forgiving of alignment issues and the minimal distortion ensures better quality images.
Here is the first books scanned with this scanbox
Camera used : Android Phone Honor 9N
@tshrinivasan Considering, the low-cost and OSS setup, the quality of the scan for this PDF is great. Kudos. If you are going to release this book (PDF) as such, I will request you add the tesseract OCR support as well so that the text becomes searchable. Thanks.