Finally I went for OCRmyPDF (https://github.com/jbarlow83/OCRmyPDF), which uses tesseract for the actual OCR part (https://github.com/tesseract-ocr/tesseract) - as I understand tesseract is a OCR tool that has been open-sourced by Google.
OCRmyPDF has great documentation, also works from the command line and has many language packs:
ocrmypdf -l eng ...
OCR generally works by trying to recognize black text characters on white background, so most OCR approaches try to “binarize” the image and convert it to black and white.
Considering the image you are using, there are a number of issues here that make this difficult:
The grey background has shades close to the pencil writing and the line.
The penciled ...
Having ImageMagick, potrace and pdftools (disclaimer: I am the author of pdftools). Assuming you have an input PDF file called input.pdf:
Convert every page in a BMP file using ImageMagick:
magick convert -density 300 input.pdf -quality 100 ./bmp/input.bmp
(optional) pre-process image files:
for /r %%i in (./bmp/*.bmp) do mkbitmap ...
If you have a lot of handwritten text from a single author you can train some OCR systems on that text and possibly get a reasonable accuracy rate but do not expect anything much above 80% unless the author has a near machine look script - after all we all have problems reading some peoples hand written text sometimes even our own.
Among the OCR systems ...
Possibly, for August, 2019 there are no programs suitable for all @Doug requirements.
In section “Suggestion” I suggest alternatives. See “Problems” section, to find out what disadvantages of these alternatives do I consider significant.
This answer is relevant for 19 August, 2019. In the future data of this answer may be ...
Syncfusion Essential PDF supports OCR by using the Tesseract open-source engine. With a few lines of code, a scanned paper document containing raster images is converted to a searchable and selectable document.
You can able to get the data from the invoice PDF or image using OCR processor in our Essential PDF. Please refer the below link for more details,
Have a look at OCRvision. OCRvision is a searchable PDF software. It can convert any scanned documents in a folder to searchable PDF automatically. It supports multilingual OCR.It can be configured for both scanned PDF and image files then convert to searchable pdf
Disclaimer :- I am associated with OCRvision as a developer
If you are interested in a commercial solution, you can check out the LEADTOOLS OCR SDK. There is no machine training needed and it can run straight out of the box. Disclaimer: I am an employee of this company.
OCR can be performed on an image with only a few lines of code:
OcrEngine ocrEngine = OcrEngineManager.createEngine(OcrEngineType.LEAD);
You can use
I have used tesseract (first option) and found that it is quite accurate (not 100% in my case). I directly used trained data for recognition.
You can start with following code.
Tesseract tess = new Tesseract();
tess.setDatapath(tessDataPath); //Path to tessdata ...
Yes, I use Tesseract. It provides language files for Hebrew language also. Following is an output of the package available on Debian GNU/Linux. This software is licensed under Apache License, Version 2.0
$ apt search tesseract-ocr-heb
Full Text Search... Done
tesseract-ocr-heb/oldstable 3.04.00-1 all
tesseract-ocr language files for Hebrew