Date type fixer

[Channingss]

Fixes #2911

When the hand is covered, there are too many unicomblock, which resulting in a large m_iNowIdx, but the data type is unsigned short, make data overflow to zero.

opencv_contrib/modules/wechat_qrcode/src/zxing/common/unicomblock.hpp

Line 35 in 8eec886

unsigned short m_iNowIdx;

and it will fall into an infinite loop:

opencv_contrib/modules/wechat_qrcode/src/zxing/common/unicomblock.cpp

Line 103 in 8eec886

if (iPosition >= 0 && iPosition < int(m_vcIndex.size()) && 0 == m_vcIndex[iPosition]) {

so we need modify data type from unsigned short to unsigned int.

force_builders=linux,docs

[Channingss]

Just waiting for Maintainers to trigger CI manually.

[alalek]

Thank you for contribution 👍

[billyany]

This just fixed crash and didn't get close to the program getting stuck for a long time，I tested a 4.5mb image, which took as much as 2m28.953s

[Channingss]

This just fixed crash and didn't get close to the program getting stuck for a long time，I tested a 4.5mb image, which took as much as 2m28.953s

@alalek We also encountered this problem.

[dddzg]

Hi, @Channingss and @billklk .
Thanks for you attention. The wechat qrcode module is mainly designed for mobile phone with normal image. To high decoding accuracy, we will try a lot of different binarizers(Hybrid, FastWindow and etc) and pattern finders(scan line algorithm and use connected cells algorithm), which will take more time.

Try to decrease the binarizers(

opencv_contrib/modules/wechat_qrcode/src/binarizermgr.cpp

Line 17 in d5317d6

m_vecRotateBinarizer.push_back(Hybrid);

) and pattern finders (

opencv_contrib/modules/wechat_qrcode/src/zxing/qrcode/detector/finder_pattern_finder.cpp

Line 238 in d5317d6

// use connected cells algorithm

)

As far as we observe, connected cells algorithm may take more time. You can try to disable it.