Tricky QR codes

[Bossofnova]

Hi all,

I'm having trouble reading these QR codes. Any idea on why? I can't tell if the format is off or anything; I can read them with my phones barcode scanner, so that's why it's bugging me.

Thanks in advance!

[MikeeB]

Hi

I had a quick look and not being a QR code expert, I tried the suggest values button on the QR Code read. It automagically set the values fro me and read straight away. Without any extra images to try it on I couldn't test it further. Try the suggest values and see how it works out.

Mike

[Bossofnova]

Hey Mike,

Thanks for your help. I tried suggest values, but it still couldn't read the code. Would you be able to try the same method on the 2 QR codes I attached? Somehow they didn't attach with my original post.

Also, which version of Labview are you using? I'm on 2011 service pack 1; I'm wondering if I should try upgrading.

[AnalogKid2DigitalMan]

002 worked right off the bat, but even with suggested values I was unable to decode 001 and 003.

-AK2DM

[MikeeB]

I have a feeling it is to do with cell size. The codes are quite small. Could you take images roughly 640 x 480 pixels and have the code fit the image like these do. As the lighting is not optimal on these, I have ben playing with thresholding and I get some grainy images on the edges of the cells. When this is rotated in 1 and 3 then it gets worse and we are around the 3 to 4 pixels per cell edge. 

This is all based on my knowledge of DataMatrix codes but I believe it should hold true for QR codes too.

Mike

[toto69]

Hi, seems these codes are really hard to decode.

I managed to decode only one of your codes.

Then I tried with an online decoder tool, the result was exactly the same. http://zxing.org/w/decode.jspx

So it seems those QR are not correctly encoded.

Regards

[Bossofnova]

Thanks for the help all! Looks like the codes are bad quality. Still, they visually look ok, so I'll probably keep trying. Maybe some computer vision enhancements like hole filling or dilation? 

[MikeeB]

Hi

When you were reading them with the phone scanner were you reading with the camera directly, or with an image of the code as you posted here?

I still think that the resolution is too low.

Mike

[Bossofnova]

I get a 1920x1200 image and search for the qr code from there. 

You're definitely right about the resolution being too low, but unfortunately this is all my project allows for. The camera must be set up a certain distance away from the qr code, where it takes a 1920x1200 image. The resulting resolution of the images I provided is directly from cropping the code out of that image. 

[BruceAmmons]

The resolution is fine.  I doubled the resolution on all the images, and image 2 is still the only one that will read.  I randomly rotated each of the images, and image 2 was still the only one that would read.

Since images 1 and 3 have the same barcode in them, I would suggest that the barcode was encoded incorrectly, or with a method that is not compatible with most readers (including NI's).  I think the reader is working just fine.

Bruce