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QR ec math help

So, I could use a little help here.Esoteric, but I still need some help from my QR community.

If using a higher level of EC, gives me more data pixels – as a designer how should I be thinking about EC?

Ex. If I ASSUME that I have 25 data pixels x and y, that would be 625 total. If I boost the EC to level H, 30 percent, that would give me 625 x 1.3 = 812.  I have another 200 pixels to worry about. And, if I am distorting them intentionally to make a designer code, at what point is higher levels of EC not beneficial to my needs? If I am distorting more pixels, is a higher EC really incrementally better?

What is the optimal level I should be shooting for?  Is this a valid question, or am I thinking about percentages in the wrong way?Not to mention, the higher EC, the more dense the code, which can be problematic.

Am  I making any big assumptions that I have overlooked.

Thank you for your help.



  1. June 7, 2010 at 9:39 pm

    Patrick, the way I approach EC depends on the environment where it will be placed and from what distance it will be scanned. If you intend to create billboard-sized codes a higher EC will actually scan better from a distance. However, the QR code on the Madison Square Garden Dino exhibit is only M-level and it probably has a pretty high scan success rate due to the sheer size of it and the fact that viewers can get fairly close to it. It boils down to camera quality and proximity.

    I recently completed a walking tour for an exhibit at a local museum and there are some low light situations so I chose to create my codes at H-level EC. This helps ensure successful scanning in the shadowy environment. I also picked a high EC because the viewer can scan the code from very close up so there shouldn’t be any focusing problems.

    For printed advertising where I have created codes slightly smaller than 1 inch square I chose to use L-level EC because of the issue of code complexity that comes into play with the higher levels of EC. I also use a very short URL, dropping the WWW off the front and type in CAPS because it creates a smaller code than lower case.

    So for me it really depends on the application and so it should for you too. I think higher EC would give you more creative freedom to distort the code for artistic purposes but if you’re designing around the code then M-level is a fairly safe bet.

    That’s my 2 cents.

  2. June 8, 2010 at 3:35 am

    the upper case is a good tip. I will try that out. Thank you.

    I think I am going to ping some CS people to see if they can explain to me the code.


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