As usual with Tesseract it's great if you want generic OCR that gives 97-98% accuracy with little to no work, but it's never going to hit 100% or near across al

As usual with Tesseract it's great if you want generic OCR that gives 97-98% accuracy with little to no work, but it's never going to hit 100% or near across all fonts, diagrammatic input etc. I have just given up on Tesseract for parsing engineering diagrams where the one single font is used throughout and rolled my own non-ML OCR using opencv that requires a little setup but easy hits 99.9% on a character basis and is way quicker, plus uses way less data stored. I couldn't get Tesseract to pick Z against 2, I against 1 etc reliably when no serifs, no matter what i did for preprocessing - dilate/erode, threshold, border, contours with smoothing, x2 and x5 resize, all the modes and so on. Because it's engineering diagrams only limited contextual guidance can be used, it's basically independent characters each time. They say retraining Tesseract won't help, but surely it would for certain fonts - what am I supposed to do about the 1 vs I then, as one example? I could pre or post process, but once I set up to do that for a few specific cases I can do a little more and then do the whole alphabet and get way better performance without Tesseract at all. And then there is the stupid Autocad font designed for pen plotters like HP-7585 or HP-7475 that no one owns any more, but the font with the square zero lives on, and that is a problem on it's own. Anyhoo, I tried out the OCRmyPDF on a few things, it could be useful in the right circumstances, but by no means magic. Nanonets or pdfsumo seem to do way better, plus can handle tables.