Feat: Add OpenCL support for AKAZE features #28879
Implement OpenCL-accelerated AKAZE feature
detection and descriptor extraction
Benchmarked on RTX 5060 Ti: 1.2x to 3.31x faster
for image sizes from 640x480 to 3840x2160
- Added 8 OpenCL kernels for feature detection and descriptor extraction
- Refactored compute_kcontrast to use OpenCV magnitude() for consistency
- Added comprehensive tests with >95% accuracy vs CPU baseline
### 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
- [ ] 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.
- [x] The feature is well documented and sample code can be built with the project CMake
BFMatcher::match() with crossCheck=true previously skipped the OCL
dispatch in knnMatchImpl entirely, falling back to CPU even when UMat
inputs and an OpenCL device were available. This adds
ocl_matchWithCrossCheck() for CV_32FC1 descriptors (e.g. SIFT, SURF):
both the forward and reverse nearest-neighbour passes run on the GPU
via the existing ocl_matchSingle() kernel, then the cross-check filter
runs on the CPU. Only two small index arrays (1×N ints) are downloaded
— the O(N²×D) distance work stays on the device.
The OCL dispatch in knnMatchImpl is also refactored to unify the
Mat/UMat train collection selection before branching on crossCheck.
On a NVIDIA RTX 3060 with SIFT descriptors the OCL path is 6–9×
faster than CPU at 2k–10k features per image. Binary descriptors
(ORB, BRIEF — CV_8U) are unaffected; the existing type guard in
ocl_matchSingle keeps them on the CPU path as before.
Also adds a correctness test (Features2d_BFMatcher_CrossCheck) and an
OCL perf test (BruteForceMatcherFixture/MatchCrossCheck).
- 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
[GSOC] Speeding-up AKAZE, part #1 (#8869)
* ts: expand arguments before stringifications in CV_ENUM and CV_FLAGS
added protective macros to always force macro expansion of arguments. This allows using CV_ENUM and CV_FLAGS with macro arguments.
* feature2d: unify perf test
use the same test for all detectors/descriptors we have.
* added AKAZE tests
* features2d: extend perf tests
* add BRISK, KAZE, MSER
* run all extract tests on AKAZE keypoints, so that the test si more comparable for the speed of extraction
* feature2d: rework opencl perf tests
use the same configuration as cpu tests
* feature2d: fix descriptors allocation for AKAZE and KAZE
fix crash when descriptors are UMat
* feature2d: name enum to fix build with older gcc
* Revert "ts: expand arguments before stringifications in CV_ENUM and CV_FLAGS"
This reverts commit 19538cac1e.
This wasn't a great idea after all. There is a lot of flags implemented as #define, that we don't want to expand.
* feature2d: fix expansion problems with CV_ENUM in perf
* expand arguments before passing them to CV_ENUM. This does not need modifications of CV_ENUM.
* added include guards to `perf_feature2d.hpp`
* feature2d: fix crash in AKAZE when using KAZE descriptors
* out-of-bound access in Get_MSURF_Descriptor_64
* this happened reliably when running on provided keypoints (not computed by the same instance)
* feature2d: added regression tests for AKAZE
* test with both MLDB and KAZE keypoints
* feature2d: do not compute keypoints orientation twice
* always compute keypoints orientation, when computing keypoints
* do not recompute keypoint orientation when computing descriptors
this allows to test detection and extraction separately
* features2d: fix crash in AKAZE
* out-of-bound reads near the image edge
* same as the bug in KAZE descriptors
* feature2d: refactor invariance testing
* split detectors and descriptors tests
* rewrite to google test to simplify debugging
* add tests for AKAZE and one test for ORB
* stitching: add tests with AKAZE feature finder
* added basic stitching cpu and ocl tests
* fix bug in AKAZE wrapper for stitching pipeline causing lots of
! OPENCV warning: getUMat()/getMat() call chain possible problem.
! Base object is dead, while nested/derived object is still alive or processed.
! Please check lifetime of UMat/Mat objects!
Anand Mahesh
Alexander Alekhin
Jiri Horner
Alexander Alekhin
Ilya Lavrenov
Vadim Pisarevsky
Alexander Alekhin
Konstantin Matskevich