One of the lovely aspects of QR codes is the variable levels of
error correction built in. On even the most basic code you can
obscure or deform up to 7% of the code and most readers will
still decode it. This leads us in to the amusing territory of
"hiding" human readable data in the code. I say "hiding" because
we are hiding it from the scanner - not from the human. One of
the more famous examples of this is Duncan Robertson's BBC logo.
After my sojourn alien hunting in Paris, I realised that there
is another blocky character which most people will recognise -
the humble Space Invader! We can also use Duncan's technique and
obscure part of the code. How Not To Be Seen While the boys of
Monty Python can tell you how not to be seen, for computer
vision, it's rather different. Essentially, what most QR
scanners do is look at a greyscale view of the image in front of
them. The lighter the colour, the more likely the optical
recognition algorithm is to see it as "white". This allows you
to put dark coloured QR c