3 ms·
1.5 kb/s at 5 cm is rather bad. Assuming 24fps (typical smartphone camera) sample rate with QAM-256 modulation, shouldn't the bandwidth be at least a magnitude
by melony 5y ago
1.5 kb/s at 5 cm is rather bad. Assuming 24fps (typical smartphone camera) sample rate with QAM-256 modulation, shouldn't the bandwidth be at least a magnitude higher even after error correction? They have 16 LEDs, assuming half are fiducial markers, they will have 8 extra channels.
- kortex 5y agoHow do you do quadrature modulation of light? There's no phase information? Or do you just mean 8-bits-per-symbol encoding? Or does the amplitude of the led vary continuously? I was assuming PCM.
- charcircuit 5y agoWhere are you seeing 16 LEDs? Everything on the site seems to suggest it's a single LED. I'm not sure how you reach 1.5kbps with a single LED on a wide range of phones.
- londons_explore 5y agoWith the rolling shutter of smartphones, combined with the fact the light from the led will spread slightly throughout the frame (dirt in the lens etc), you effectively get one piece of information per row of the image. So a 1080p60 video, which most phones are capable of, gives you 64kbps. With no feedback channel though, one can't characterize the channel though, so you need to have super large margins to be sure it's going to work.