The Optical Character Recognition (OCR) is the recognition of printed or written text characters by Mobile Camera. This involves photo scanning of the text character-by-character, analysis of the scanned-in image, and then translation of the character image into character codes, such as ASCII. This Library will scan the text character and return the text in string format to your project. This source code is posted by google on Github. https://github.com/googlesamples/android-vision/tree/master/visionSamples/ocr-reader

Go though with OCRLibraryGuide for Integration of OCR Library into your project.