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I wonder if there's anyone scanning satellite imagery for the word "HELP", or if we should agree on some other symbol people could use to ask for help that woul
by shpx 7y ago
I wonder if there's anyone scanning satellite imagery for the word "HELP", or if we should agree on some other symbol people could use to ask for help that would be easier to discover with computer vision and wouldn't be English-specific.
How large should you make the letters? Satellite resolutions range from 2m for Planet Labs, 50cm for Geoeye to ~10cm for that spy satellite Trump leaked recently. The MNIST dataset of hand written digits uses 28*28 pixels, but you can get away with less. Maybe 50 meter by 50 meter letters?
If you know binary you could also include extra information by using rows of 5 squares ~1m in diameter.
- hinkley 7y agoHow about "bigger than a sedan at the bottom of a pond"?
- shpx 7y agoGoogle Maps uses aerial imagery (photos taken from planes)[0] because it's higher resolution, and I bet that's what you're seeing here. They don't fly those planes often and they don't fly them over random uninhabited islands, whereas there's a company that takes satellite images of all the land on the planet daily. [0] https://support.google.com/earth/answer/6327779?hl=en https://support.google.com/earth/answer/6327779?hl=en
- journalctl 7y agoI can’t imagine getting the entire world to learn a new symbol for “help” on the off chance someone needs to signal to passing satellites. Also, I believe SOS is fairly well-known.
- ada1981 7y agoHow frequently do we refresh our coverage of imagery of planet earth? Some sort of universal symbol could be great. Especially if you knew that within X days there was a strong chance it would be spotted and rescue folks alerted.