It depends on what is being scanned. Say you have a perfectly formatted image, directly taken from a scanner, it's a pretty darn quick process.
But from my experience, what adds to the slowness is pre-processing the image to make it suitable for OCR, especially tesseract. I still haven't found the magic combination of filters because every image is different, especially if your source them from users camera phones.
But from my experience, what adds to the slowness is pre-processing the image to make it suitable for OCR, especially tesseract. I still haven't found the magic combination of filters because every image is different, especially if your source them from users camera phones.