some fonts do indeed scan better than others. this is not a tesseract problem, but is a common problem for all OCR, including the commercial ones. although they do differ in terms of output quality still

what's the quality of your input image like? do you do image cleanups on it?

you can probably try something like this: http://www.fmwconcepts.com/imagemagick/textcleaner/

to clean up the image to make the text clearer for the OCR to process

apart from that, have you tried doing tesseract training?

CounteReborn, post your image here and let us see.

If by "IC" you mean the Mykad, there are blue coloured patterns behind the number. The IC number itself is black. You can filter out the background so that tesseract only sees the number in front of a blank background.

Restrict the recognition to numbers only, to improve the recognition rate.

I think there is a way to force Tesseract to limit it to only some characters.

And IIRC, Tesseract does not use dictionary lookup/spellcheck, which is why it's recognition rate for normal text is pretty poor.

Can't remember the command line option now. We used Tesseract a couple of years back in a project to scan receipts. The OCR was only to pick out the receipt number so that the image file can be stored with the appropriate filename/receipt number. With additional code to pick out the receipt number and clean up the area around it, the error rate was less than 10 per 10,000 receipts. A lot depends on your image quality. And there is an optimal size for the characters (in number of pixels). It's in the documentation. Too small or too large, and the recognition rate drops.

From wiki
https://en.wikipedia.org/wiki/Tesseract_(software)