Algorithm to detect presence of text on image

Question

With my new assignment I am looking for a method to detect the presence of text on image. The image is a map - can be for example google map. The task is to detect where the

Answer 1

There are several possible approaches you can take.

1. Use OCR. A search for OCR on Stackoverflow will show many options. These include Tesseract and Ocropus.
2. If your text uses very specific fixed font, you may get away with simple template matching.
3. In the more general case you might want to take a look at "Detecting Text in Natural Scenes with Stroke Width Transform"

UPDATE Jan. 2017
The OpenCV 3.2 contrib module now has a text detection module.
It also includes a sample of how to use it.