Here are some useful resources for open source C and C++ -based OCR libraries that could run under iOS (need to check licensing):
- Seven Segment Optical Character Recognition (ssocr)
- Advice for 7-Segment Display OCR with Tesseract
- Tesseract OCR iOS library
The end goal is to be able to use an iPhone to read LED displays, as commonly found on meters, etc. and then do something useful with that data (upload it somewhere, tagged with geodata). An aggregate of hundreds or thousands of users could conceivably collect data useful for themselves and also for the group as a whole.