It's pretty much as other people talked about, I used OpenCV to try to detect the board, and then isolate each tile, and then used Tesseract to try to figure out the letter. The biggest problem I had was whenever the red score bubble landed on a tile, it would fall on top of the latter and thus lose information so I ended up having to create training data and associating that to get the letter. I was able to get to about 98% accuracy and it was relatively robust until they created a new app that I haven't had time to adjust for.
I think this is the best solution, though a bit daunting without experience in either to approach. But you'll get access to processing all of your information in a low level language very quickly.
I'm just starting out on something similar (OCR'ing letters from a word game), so would also love to here more about the process you're using with Tesseract and OpenCV.
I did it to count the tiles, and was going to work on a full-on cheating program but never got around to it. I did find the algorithm online though, it's pretty interesting.
