Android sample app which provides distance of an object from the camera; using contour based image recognition through OpenCV. This project is avilable on google play store as an example.

• Place an object with a highlighted boundry in front of your phone.
• Take a picture and enter its initial ditance and length of its perimeter, all in centimeters.
• Now move the phone some distance away and take the picture again.
• A distance, from phone to object, will be displayed.
• Approx. error ~2cm.

Tested on Nexus 5.

I have used code from the following projects and do not own them

1. Google's android camera2basic example code: https://github.com/googlesamples/android-Camera2Basic

2. OpenCV android library by vRallev: https://github.com/vRallev/OpenCV

I would like to acknowledge the work of Adrian Rosebrock on object distance detection with opencv-python: http://www.pyimagesearch.com/2015/01/19/find-distance-camera-objectmarker-using-python-opencv/