Add a check for src == dst in ocl warpTransform #25898
As mentioned in #25853, when doing WarpAffine with Mat and UMat respectively, if you force the use of the in-place operation (so that src and dst are passed the same variables), Mat produces the correct results, but UMat produces unexpected results.
Obviously in-place operations are not possible with this transformation. When Mat performs the operation, if dst and src are the same variable, the function inherently makes a copy of src without telling the user.
74b50c7af0/modules/imgproc/src/imgwarp.cpp (L2831-L2834)
So I did the same check in UMat, but I'm not sure if it's appropriate, should we just do a copy operation without telling the user (even if the user thinks he's doing an in-place operation), or should we throw an exception to indicate that we shouldn't pass in two same variables here?
The possible reason for this problem is that there is a create function here, so it gives the developer the false impression that this create function has allocated new memory for dst, however it does not.
74b50c7af0/modules/imgproc/src/imgwarp.cpp (L2607-L2609)
Because by the time the check is done here, the function has returned back.
74b50c7af0/modules/core/src/umatrix.cpp (L668-L675)
### Pull Request Readiness Checklist
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- [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
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Patch to opencv_extra has the same branch name.
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First proposal of cv::remap with relative displacement field (#24603) #24621
Implements #24603
Currently, `remap()` is applied as `dst(x, y) <- src(mapX(x, y), mapY(x, y))` It means that the maps must be filled with absolute coordinates.
However, if one wants to remap something according to a displacement field ("warp"), the operation should be `dst(x, y) <- src(x+displacementX(x, y), y+displacementY(x, y))`
It is trivial to build a mapping from a displacement field, but it is an undesirable overhead for CPU and memory.
This PR implements the feature as an experimental option, through the optional flag WARP_RELATIVE_MAP than can be ORed to the interpolation mode.
Since the xy maps might be const, there is no attempt to add the coordinate offset to those maps, and everything is postponed on-the-fly to the very last coordinate computation before fetching `src`. Interestingly, this let `cv::convertMaps()` unchanged since the fractional part of interpolation does not care of the integer coordinate offset.
### 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
- removed tr1 usage (dropped in C++17)
- moved includes of vector/map/iostream/limits into ts.hpp
- require opencv_test + anonymous namespace (added compile check)
- fixed norm() usage (must be from cvtest::norm for checks) and other conflict functions
- added missing license headers
Add new OpenCL kernels for bicubic interploation, it is 20% faster
than current warp image kernel with bicubic interploation.
Signed-off-by: Li Peng <peng.li@intel.com>
Add new ocl kernels for warpAffine and warpPerspective,
The average performance improvemnt is about 30%. The new
ocl kernels require CV_8UC1 format and support nearest
neighbor and bilinear interpolation.
Signed-off-by: Li Peng <peng.li@intel.com>
