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by cwmma 3977 days ago
> No. Unlike QR codes, meshtags of any color on any background can be scanned. There just needs to be enough contrast between the meshtag and its background, and the background must be a solid color.

qr codes can be any color, just need to have enough contrast, also depending on the redundancy level of it you can actually omit a significant fraction of the qr code and still have it scan

3 comments

You can take it up to 11 like this: http://files.rya.nc/qr.png
I don't see anything on your blog about how that QR code can possibly work (I just scanned it, it does work, but my eyes tell me that's impossible)

You have any background on how that QR was constructed?

The very short explanation:

* Split source image into red, green, and blue channels

* Run through the halftone qr generator[0]

* Recombine resulting QR codes into an RGB image

* Average combined QR codes with the source image

I'll probably post an article walking through the process using imagemagick some time next in August.

0. http://vecg.cs.ucl.ac.uk/Projects/SmartGeometry/halftone_QR/...

You can even use the error tolerance to embed an image http://research.swtch.com/qr/draw
You are right. However, I think most scanners only scan dark QR codes on light backgrounds, which is not the case with Meshtag. You can draw on chalkboards, pavement, etc.