Mobile App for Vision Impaired

My mother-in-law is 90 years old and suffers from retinitis pigmentosa which renders her legally blind. On a recent trip she commented that with her dark glasses and the tint of the car windows she was able to see the guard rails on the highway against the trees behind them. I am looking to combine a low-cost VR headset with an app (probably will need to be Android but would prefer to keep it cross-platform) that can basically provide video (no need for 3D I don't think) that will be filtered in such a way as to darken the image to prevent white-out but provide a level of contrast allowing objects to be recognizable. I am a Xamarin developer and have been thinking about this for a while but do not have time nor the specific expertise to do it on my own. I'm hoping to find someone who can help. I am open to using Xamarin with EMGU (OpenCV for .NET) or perhaps Unity to accomplish this. If ARKit on iOS is a good way to go, I am open. The advantage to using EMGU is that it will allow us to do other things like real-time edge detection and maybe provide a high-contrast reader allowing her to read from a book. Since this is a personal project and do not plan to market this, I need to try to keep the costs down so licensing software to build this is not really feasible. I would require that I have access to the source code and all rights will belong to me.