|
|
|
|
|
|
by fake44637
3923 days ago
|
|
|
This inspired me prototype out a system which would use QR codes and use a smartphone camera for recovery, rather than a flatbed scanner. Here's a demo PNG file which contains 48 QR codes (6x8) at V23 level with L correction (~7% recovery). That's 1091 bytes per code, or just over 51KB per page when printed at 300 dpi. This level of density seems to be very reliable using ambient lighting and an iPhone 5c. I was also able to read a QR code which was 66% of that size, but it required turning on the iPhone's flash in order to be reliably read. That level of density would allow fitting 9x12 codes on a single page at 300 dpi, which would yield 115KB of data per page. (At first I tried using 600 dpi, but at 1 dot per pixel the codes were totally unreadable by a cell phone. The above 115KB/page density is the equivalent of 4 dots per pixel at 600 dpi. The good news is this means the system doesn't require a 600 dpi printer. In fact, at 1 dot per pixel, the 51KB/page density is equivalent to 100dpi, and the 115KB/page density is equivalent to 150dpi). |
|
|