allow cv::resize to support more than 4 channels in AREA path - #29691
Fixes #29651
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The IPP HAL (hal/ipp/src/warp_ipp.cpp) routed cv::warpAffine with
INTER_NEAREST to iwiWarpAffine for CV_16S{C1,C3,C4}, CV_64F{C1,C3,C4}
and CV_16UC4 via the non-enforced (default) impl[] dispatch table,
whose comment promises results "strictly aligned to OpenCV
implementation". That contract was broken: IPP rounds source
coordinates at the half-pixel boundary differently from the native
fixed-point kernel (warpAffineBlocklineNN, 10-bit AB_BITS), so under
rotation or fractional translation about 0.05-0.07% of destination
pixels resolve to a different source pixel. Because INTER_NEAREST does
no blending, those pixels take entirely different values, so warping
identical data as e.g. CV_16S (IPP path) versus CV_16U (native path)
produced non-identical output, and x86_64 (IPP) silently diverged from
ARM (no IPP). This is the same "Different results" behavior for which
IPP warpAffine was disabled from ~2017 through 4.11.
Zero the INTER_NEAREST column of the non-enforced dispatch table for
the affected types so the dispatch guard falls back to the native
kernel, restoring the "strictly aligned" contract. The LINEAR and
CUBIC columns for these rows were already 0, so IPP was only ever used
for NEAREST here. The IPP_CALLS_ENFORCED table is left untouched so the
opt-in performance-benchmarking build still exercises IPP.
Adds a regression test (Imgproc_Warp.regression_29279) that warps a
gradient image with INTER_NEAREST as each affected type and asserts
bit-exact equality with a native (CV_32F) reference across several
rotation angles and a fractional translation.
Fixes#29279
Fix IPP warpAffine #28562
The issue is that we compute the inverse transformation and pass that to the HAL, but tell IPP that we use the actual transformation.
a269a489b9/modules/imgproc/src/imgwarp.cpp (L2399-L2412)
I have added an additional test with `CV_16S` Mats to test the IPP implementation, because right now no other `warpAffine` test enters the IPP branch.
This fixes#28554.
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Fix getPerspectiveTransform for singular case #26926
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Fix#26916
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Support C++20 standard #26590
Close https://github.com/opencv/opencv/issues/26589
Related https://github.com/opencv/opencv_contrib/pull/3842
Related: https://github.com/opencv/opencv/issues/20269
- do not arithmetic enums and ( different enums or floating numeric)
- remove unused variable
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core: C-API cleanup: RNG algorithms in core(4.x) #26259
- replace CV_RAND_UNI and NORMAL to cv::RNG::UNIFORM and cv::RNG::NORMAL.
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imgproc: remove C-API usage from tests #25842
Final cleanup will be done in 5.x after regular merge.
Some tests have been reworked, some required only slight modifications.
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.
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Fix imgwarp at borders when transparent. #23922
I believe this is a proper fix to #23562
The PR #23754 overwrites data while that should not be the case with transparent data. The original test is failing because points at the border do not get computed because they do not have 4 neighbors to be computed. Still ,we can approximate their computation with whatever neighbors that are available.
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Keep inliers for linear remap with BORDER_TRANSPARENT #23754
Address https://github.com/opencv/opencv/issues/23562
### Pull Request Readiness Checklist
resolves https://github.com/opencv/opencv/issues/23562
I do think that this is a bug because with `INTER_CUBIC + BORDER_TRANSPARENT` the last column and row are preserved. So same should be done for `INTER_LINEAR`
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Bit-exact Nearest Neighbor Resizing
* bit exact resizeNN
* change the value of method enum
* add bitexact-nn to ResizeExactTest
* test to compare with non-exact version
* add perf for bit-exact resizenn
* use cvFloor-equivalent
* 1/3 scaling is not stable for floating calculation
* stricter test
* bugfix: broken data in case of 6 or 12bytes elements
* bugfix: broken data in default pix_size
* stricter threshold
* use raw() for floor
* use double instead of int
* follow code reviews
* fewer cases in perf test
* center pixel convention
* Fix NN resize with dimentions > 4
* add test check for nn resize with channels > 4
* Change types from float to double
* Del unnecessary test file. Move nn test to test_imgwarp. Add 5 channels test only.
* integrated the new C++ persistence; removed old persistence; most of OpenCV compiles fine! the tests have not been run yet
* fixed multiple bugs in the new C++ persistence
* fixed raw size of the parsed empty sequences
* [temporarily] excluded obsolete applications traincascade and createsamples from build
* fixed several compiler warnings and multiple test failures
* undo changes in cocoa window rendering (that was fixed in another PR)
* fixed more compile warnings and the remaining test failures (hopefully)
* trying to fix the last little warning
* Rewrite polar transformations
- A new wrapPolar function encapsulate both linear and semi-log remap
- Destination size is a parameter or calculated automatically to keep objects size between remapping
- linearPolar and logPolar has been deprecated
* Fix build warning and error in accuracy test
* Fix function name to warpPolar
* Explicitly specify the mapping mode, so we retain all the parameters as non-optional.
Introduces WarpPolarMode enum to specify the mapping mode in flags
* resolves performance warning on windows build
* removed duplicated logPolar and linearPolar implementations
- 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
Added assertios to remap and warpAffine functions
As @mshabunin said, remap and warpAffine functions do not support more than 4 channels in
Bicubic and Lanczos4 interpolation modes. Assertions were added. Appropriate test was chenged.
resolves#8272
Warping a matrix with more than 4 channels using BORDER_CONSTANT and
INTER_NEAREST, INTER_CUBIC or INTER_LANCZOS4 interpolation led to
undefined behaviour. This commit changes the behavior of these methods
to be similar to that of INTER_LINEAR. Changed the scope of some of the
variables to more local. Modified some tests to be able to detect the
error described.
