Startup Idea : App for Blind And Visually Impaired people walking

I see that todays technologies is getting more efficient and i haven't see any app for people with needs like blind or visual impaired where could make it easier to walk in different environments like cities where everything is in constant change meking difficult just to follow a gps route from any gps map My idea here is with the help of a camera on mobile devices and gps tracker, use it to read the walking environment and detect hazards on the visual impaired person pathway, and make it easier for the person to avoid different obstacles, like a virtual cam with reference for a safe walk.