ZBar bar code reader / Support Requests / #183 QRcode from screen photo not recognized

#183 QRcode from screen photo not recognized

Milestone: latest_mercurial

Status: open

Owner: nobody

Labels: None

Priority: 5

Updated: 2022-06-12

Created: 2021-10-27

Creator: Jan Yenya Kasprzak

Private: No

Hello,

my users submited some QR codes which are photos from the monitor, and some of them cannot be recognized. For some of them, I get the following assert failure:

WARNING: decoder/databar.c:1248: _zbar_decode_databar: Assertion "seg->finder >= 0" failed.
i=25 f=-1(010) part=0

I can't attach the original QR codes, as they are Digital COVID certificates containing personal info, but I made a sample containing random text, which also cannot be recognized (but does not trigger the assert() above). Both the attached files are not recognized by zbarimg, but can be recognized using BinaryEye android app from the F-Droid repository.

My system is Fedora 34, uname -a says:
Linux my.host.name 5.13.4-200.fc34.x86_64 #1 SMP Tue Jul 20 20:27:29 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
$ rpm -qf /usr/bin/zbarimg
zbar-0.23-8.fc34.x86_64

1 Attachments

random_qr_monitor.jpg

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Jan Yenya Kasprzak - 2021-10-27

Second sample

qr2.jpg

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grustbal - 2022-06-12

zbarimg version 0.23.91 can successfully read both images, but only after making them smaller: convert qr2.jpg -scale 500x small2.jpg

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QRcode from screen photo not recognized

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#183 QRcode from screen photo not recognized

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