I am trying to use OpenCV (Android) for processing image taken using camera and then pass it to Tesseract for text (digits) recognition but am not getting good results till
You can isolate/detect characters in images. This can be done with powerful algorithms such as the Stroke Width Transform.
The following steps worked well with me:
Please note, for step 4 you will need to build the c++ library in the link and then import into your android project with JNI wrappers. Also, you will need to do micro tweaking for all steps to get the best results. But, this should at least get you started.