A script in bash in combination with a script in C can help you solve a sudoku puzzle in a png file.

https://gitlab.com/christosangel/sudoku-solver-ocr

You can see the script in action in this video.

The main dependency is tesseract OCR, responsible for the oprical character recognition.

Another important dependency is imagemagick, responsible for the necessary image manipulation.

The file selection of the png image is done with zenity.

Feel free to give your feedback.