WIP: Fix segfault in QRCodeDetector.detectAndDecodeCurved #23802
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AleksandrPanov
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The problem was in the original algorithm - PR #18003 @APrigarina, could you look at this solution or suggest another one? |
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@opencv-alalek Could you take a look on the solution? |
asmorkalov
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@AleksandrPanov, @asmorkalov, frankly speaking, I don't like this hack. There is a general flexible method how to interpolate any polyline or any polygon using a spline. First, you introduce "time" axis t. The simplest (and probably good enough for this purpose) method is to set t=0 for the first point, t=1 for the second point etc. Then, instead of computing spline as y=y(x) you just build splines x=x(t) and y=y(t). Then you can compute intermediate points at any precision by choosing some fractional t values. In this case you don't need the proposed hack, because you can be sure that all t's are different. |
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thanks a lot for the parametrization idea! |
asmorkalov
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| OK = 0, | ||
| NEED_SWAP_AXES, | ||
| NEED_ADD_PARAMETRIZATION |
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With parameterized spline we do not need branches any more.
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Replaced by #25026 |
Fix qrcode bugs #25026 This PR fixes #22892, #24011 and #24450 and adds regression tests using the images provided. I've also verified with the [benchmark](https://github.com/opencv/opencv_benchmarks/tree/develop/python_benchmarks/qr_codes) that this doesn't break anything there. resolves #22892 resolves #24011 resolves #24450 Replaces #23802 Requires extra: opencv/opencv_extra#1148 ### Pull Request Readiness Checklist See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request - [x] I agree to contribute to the project under Apache 2 License. - [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV - [x] The PR is proposed to the proper branch - [x] There is a reference to the original bug report and related work - [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable Patch to opencv_extra has the same branch name. - [ ] The feature is well documented and sample code can be built with the project CMake
fixes #22892
merge with opencv/opencv_extra#1072
The issue is in spline interpolation. Only the points of the function can be interpolated using splines, but the contour points may not be a function. There may be several points with the same x coordinate and different y. It results in getting NaN when calculating spline.
Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
Patch to opencv_extra has the same branch name.