This is actually kind of a placeholder for me.
Somewhere I have an idea written up about this. I saw a blind person walking along the street, and as he passed me I remembered the idea, vaguely. It is written up in quite some detail as I remember, but I don't remember much else. It was a very long time ago, so the technology level at that point would have been limited.
This is a rough idea description with modern technology in mind.
So a device about the size of a basic smart phone is normally strapped to an arm, waste, leg, or where ever, but can be handheld, and it gives a map of the area by raising and lowering small pins. Braille character idea, but not fixed, and the points vary in height. Then the user can move fingers on a free hand over the map to determine where to walk, and possibly determine where objects are. And something about vibrating them for danger. I don't know what I figured out before, but there are a lot of possibilities, and with modern batteries, this is lightweight and can go a long time before switching out batteries or direct recharging.
The sensors can be any combination of the cheap modern devices for digitizing the visual world. I think before I had a headband thing, not sure. I can be glasses like diving goggles or so.
But not doing anything on this idea, it must be done already, and just this guy I saw doesn't want to use it or doesn't yet have access to it.
So, until I run across the old idea, I'm only going to think about trying to remember to ask anybody I run into that might have knowledge in this area.