Need a Digit Recognition Android App

My health machine have a screen that displays 2-4 digits, e.g 8.9 or 13.4 The app should have a Digit Recognition Engine. Maybe the engine will be written by C++ in *.so file, called by jni interface. If I open my application and then click the Recog button, the app will call the phone camera and start digit recognizing. (e.g. 3.4 , 18.7) note: it does not mean recognizing after taking pictures, dynamic camera recognition. - Technical requirements 1. Android 4.0 and later 2. Recognition time : Less than 5 seconds. 3. Recognition environment 4. There will be a slight reflection on the screen. 5. Request for digits and point 2 or 3 or 4 digits, Decimal point must be recognized by recognition engine. e.g 8.9, 10.8 etc 6. The shapes of each Screen are same , but the color around screen may be different, red, blue, green ,etc. less than 5 color. 7. Recognition distance between Screen and Phone Camera 20 – 40 cm - Final product 1. Recognition Engine *.so file, enable to call by JNI 2. Android Studio Demo project that calls recognition engine.