ZXing can't decode a few codes from long series created by itself.

[proteusnexus]

Hi All,

I found ZXing quite usefull for my non commercial project. It does great job however I struggle a little bit to get 100% consistent results while encoding and decoding series od QR codes.

Here is my scenario. There is a "sender" and "receiver".

"Sender"

• generates series of QR codes containing some HEX data using Zxing library in Powershell,
• shows them on the screen,
• for debuging purposes all those codes are saved on the disk (PNG)

"Receiver"

• .Net app captures images from camera,
• detects QR codes and using ZXing decode the data,
• for debuging purposes all those codes are saved on the disk (PNG)

It works actually great, but it happens that 1-6 codes from ~260 long series can't be decoded for no reason. They look legit, like all other recived codes. Not distorted, blurred etc. Just sharp, grayscale images.

Since I've got original PNG files I can test if it was properly created and can be decoded without any problems. No issue here.

To test if something is wrong with the code/image received I checked them with online decoder like https://scanqr.org/ which is ZXing based. The "bad" code can be decoded without any problems.

So I'm getting a bit confusing results. Attaching one example.

Original QR code at source:

Received QR code

I would say that the quality of the received code is very good and actually the same like hundreds of other codes.

I tried to set additional options on decoder side like TryHarder, TryInverted - didn't help. Tried to adjust contrast - didn't help. Increasing ErrorCorrectionLevel on "sender" side didn't help as well.

Defnitely I'm not an expert in QR codes field, but spent already some time in this topic and now runnning out of ideas. I thought I'm almost there, but it turned out longer series always fail.

Any help will be appreciated.

Regards,
Prot