Problems with displaying QR Code on Lattice LED screen

[Valar Morghulis]

We had some problems when we tried to scan these QR code on a LED screen.

Our idea is to display QR Code on LED screen, as you can see we've already done that, but we had trouble when we tried to scan&read from these QRCode.

We think the biggest issue may be the resolution, but our goal is use this kind of screen. Btw the resolution of this lattice screen is 64*64.

Is there any solution for the client(scanner/mobile phone ) to clarify the picture that scanned in?
Or there is just one way that raise the resolution tatio?

We sincerely hope any experienced hand can help us, give us some tips or guidence! Thanks!

Sorry for my bad English!
Thanks.

[Bas Vijfwinkel]

The problem might be the amount of whitespace around the qr code.
It might be that it is just not enough for the detector to detect the corners of the qr code.
Based on my personal experience I would say the QRCode itself looks clear enough to be scanned.

The options are either increasing the whitespace around your QR code, or rewrite the corner detection routine in order to handle this limited amount of whitespace.

[Valar Morghulis]

>
> The options are either increasing the whitespace around your QR code, or rewrite the corner detection routine in order to handle this limited amount of whitespace.
>

"Increasing the whitespace around QR code"
You mean making the white borders more thick? I'll have a try, thank you very much!

[Lachezar Dobrev]

  The "white space" is actually part of the QR Code.

  Also. The lattice seems a bit low-resolution. Be VERY careful when scaling QR Codes. You may end up with pixels that are only half-lit, or you may end up having dithering, which makes reading the bar-codes extremely difficult. May I suggest that you try only integer scaling (×1, ×2, ×3), and rather leave more space around the code than scale it. Non-integer scaling when the resolutions are close can yield worse results than smaller unscaled version.

  For an instance the Version 1 (21×21) QR Code can be scaled up ×3 and end up 63×63, but the Version 2 (25×25) should be scaled ×2 only and ends up with large white space. You will not be able to display QR Codes beyond version 11 (61×61).

  It might also pay-off to put the LED/LCD lattice in a white bevel as wide as 4 pixels from the lattice, and then trim the white space from the QR code, saving on pixels. Then you may show up to version 13.

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[Sean Owen]

The problem that jumps out at me is that you do not have a quiet zone around the QR code. You need >= 4 modules of white space around it.

[Valar Morghulis]

在 2015年9月7日星期一 UTC+8下午7:43:33，Sean Owen写道：

> The problem that jumps out at me is that you do not have a quiet zone around the QR code. You need >= 4 modules of white space around it.

Sorry for my late response!
I've some trouble with my VPN so I couldn't reach the Internet outside our "Great Fire Wall". Thanks to Chinese government.

Thank you for you brilliant guide, we solved this problem. We've simply whiten the borders of the LED screen and problem solved!Best thank you!
As @Lachezar Dobrev truely taught me a lot, and I'd like to mark him as the best answer.Hope you don't mind. After all you are the auther of "zxing", all hail to Sean Owen

[Valar Morghulis]

Sorry for my late response!
I've some trouble with my VPN so I couldn't reach the Internet outside our "Great Fire Wall". Thanks to Chinese government.

Thank you for you sincere answer, the details really helped us a lot!Thought we haven't tried to add "white spaces" cause we thought it would bring more trouble, but we've simply whiten the borders of the LED screen and problem solved!
Best thanks to you!