bardecoder
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piderman314
Added test cases containing a large in-the-wild image, and two rotated versions
One of the rotated versions fails (test_wild_rotated_1), likely because the QR code is too tilted.
We don't have to retain the other two tests, as these cases are pretty much already covered.
In debug-images mode, i found that test_wild_rotated_1 gives the following candidates.png:
My naive analysis would be that the top-right finder is a false positive.
Slightly decreasing the accepted variance of the finder pattern seemed to at least make the detection work, but now decoding fails. The error correction seems to have trouble, if i read the code correctly.
Yeah you can see the debug image in the extract directory, it appears it can find the data quite accurately, but it's not 100% correct, causing it to have more errors than the correction can handle.
Come to think of it, this also has to do with the fact that this is a version 1 QR Code which doesn't have an extra alignment pattern. Can you try this kind of rotation with a level 2+ QR Code?
Ah yeah i saw that second image too. It seems to miss a few of the black squares (duh ;)). What would testing a v2 tell us? Or are v1 QR codes out of scope?
A v2 (and up) code has an extra special square in the bottom right corner that helps adjusting the angle a bit better. In the end, we have to estimate the angle and skew of the image based on discrete data (pixels). This is always going to be wrong to a certain degree, resulting in missed squares.
I'm not sure it's possible to get the estimation any better for a v1 image that has been rotated quite this much.
I'm just curious if a v2 code that has been rotated in the same way would fare better because of the extra alignment pattern. (See the version3_example test case for an example that has that pattern in the bottom right).