hal/riscv-rvv: implement laplacian #28887
OpenCV Extra: https://github.com/opencv/opencv_extra/pull/1353
An implementation of laplacian for riscv-rvv hal
Added benchmark in perf_laplacian.cpp
The performance is evaluated on K1 by running
./opencv_perf_imgproc --gtest_filter="Perf_Laplacian*"
Results are attached in the figure below.
CV_8U fast path supports ksize=3 with BORDER_CONSTANT/BORDER_REPLICATE; unsupported combinations fall back to default implementation. See performance results bellow.
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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
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The minMaxIdx dispatch table in modules/core/src/minmax.cpp stored
seven differently typed functions through C-style casts to a single
MinMaxIdxFunc pointer type, which is undefined behaviour and trips
UBSan's -fsanitize=function for any CV_32F or CV_64F input. This
change switches the typedef and every depth-specific helper to take
void pointers for src, minval and maxval, with the original typed
pointer recovered at function entry. The dispatch table no longer
needs C-style casts and the int pointer punning at the call site
goes away. Fixes#28928.
Better AutoBuffer API #28909
Mimic std::vector<> to help replacing std::vector<T> by cv::AutoBuffer<T> when possible
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videoio(dshow): fix crash in videoInput::start() when pVih is NULL #28914
### Summary
This PR fixes a critical application crash in the DirectShow backend when encountering certain legacy or virtual cameras (e.g., Microsoft's DirectShow "Ball" Sample).
### The Problem
In `modules/videoio/src/cap_dshow.cpp`, the function `videoInput::start()` calls `pConfig->GetConnectedMediaType(&mt)`.
- In some edge cases, this call returns `S_OK`, indicating success.
- However, the associated format block `mt.pbFormat` (which `pVih` points to) can still be `NULL`.
- The current implementation uses `CV_Assert(pVih)`, which triggers a hard crash of the entire application when this occurs.
### The Fix
I have replaced the `CV_Assert(pVih)` with a null-pointer check. If `pVih` is `NULL`, the function now returns `false`. This allows the high-level `cv::VideoCapture` to handle the failure (e.g., by returning `false` from `.open()`) instead of crashing the process.
### Engineering Rationale
- Execution Path Consistency: For devices providing valid format headers, `pVih` remains non-NULL. In these cases, the conditional check is skipped, and the execution path is identical to the original implementation.
- Process Stability: Replacing `CV_Assert` prevents immediate process termination (SIGABRT) when a DirectShow filter provides an invalid or empty format block.
- Error Propagation: Returning `false` in `videoInput::start()` allows the initialization failure to propagate through the call stack. This ensures that `cv::VideoCapture::open()` returns `false`, enabling the caller to detect the issue via the standard API (e.g., `isOpened()`) instead of the process being terminated.
### Evidence
I have manually reproduced this crash using the Microsoft DirectShow Ball Sample filter on Windows. As shown in the attached debugger screenshot:
- `deviceID` is 2 (the virtual camera).
- `hr` is `S_OK`.
- `pVih` is `NULL`.
<img width="773" height="1413" alt="dshow_null_pvih_debug_evidence" src="https://github.com/user-attachments/assets/5bc454b4-4a0b-4703-825d-0d5fd23cba28" />
Fixes#28904
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- Replace unsafe pointer arithmetic and direct buffer modification with std::string methods.
- Update documentation to clarify that the last digit is used as compression level and truncated from the actual filename.
- Add test cases for .gz and .gz0-9
Fix Clp library detection for vcpkg on Windows #28423
## Problem
Building OpenCV with `WITH_CLP=ON` on Windows (vcpkg) fails:
LINK : fatal error LNK1181: cannot open input file 'libClp.lib'
vcpkg generates `Clp.lib` and `CoinUtils.lib`, but OpenCV expected `libClp.lib`/`libCoinUtils.lib`.
## Solution
Modernize CLP detection with a robust, platform-aware approach:
1. **CMake `find_package(Clp CONFIG)`**: detects vcpkg and uses imported targets (`Coin::Clp`, `Coin::CoinUtils`)
2. **Fallback**: pkg-config on Unix/Linux
3. **Skip** Android/iOS
## Benefits
✅ Fixes Windows build with vcpkg
✅ Uses modern CMake targets
✅ Backward compatible with Unix/Linux
✅ Safe for CI and mobile builds
✅ Graceful fallback if CLP unavailable
## Testing
- **Windows 11 + vcpkg**: build succeeds
- **No CLP installed**: configure/build succeeds
- **Linux/Unix**: existing workflows unaffected
- **Android/iOS**: properly skipped
## Changes
- Update `cmake/OpenCVFindLibsPerf.cmake`
- Replace hardcoded library names with CMake targets
- Add mobile platform guards
- Preserve backward compatibility
Fixes#26592
---
### Pull Request Readiness Checklist
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- [x] There is a reference to the original bug report and related work (#26592)
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- [x] No additional tests required - this is a build system fix that maintains existing functionality
doc: modernize Doxygen comments to support for v1.15.0 #28903
This PR addresses several documentation build failures encountered with modern Doxygen versions, particularly v1.15.0 (shipped with Ubuntu 26.04).
- flann module: Updated license headers from /**** to /*M****. This prevents Doxygen from misinterpreting the license text (specifically the unclosed backticks in ``AS IS'') as documentation blocks, which previously caused "Reached end of file" errors.
- core module: Fixed a typo in operations.hpp where a doubled backtick (``) caused parsing to fail.
- tutorials: Fixed a missing backtick in real_time_pose.markdown (around line 108) and corrected typos in the RobustMatcher class name.
- Links: Resolved explicit link request failures in calib3d.hpp by ensuring proper namespace resolution.
These fixes ensure that the documentation can be generated without errors on the latest toolchains.
### Pull Request Readiness Checklist
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- Emscripten 5.0.1+ changed version macros to uppercase and deprecated lowercase ones.
- Updated CMake to detect the version from both cases.
- Added macro aliases in intrin_wasm.hpp to avoid deprecated warnings and ensure compatibility.
Zlib upgrade 1.3.2 #28779
### Pull Request Readiness Checklist
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videoio: fix C4576 build error with older ffmpeg versions #28894Fixes#28875
### Description
This PR fixes a build failure (`error C4576`) that occurs when building the `videoio` module with older FFmpeg versions (e.g., 4.4.4) using MSVC under strict C++17 mode.
**Root Cause:**
In older FFmpeg headers, the `AV_TIME_BASE_Q` macro is defined using a C99 compound literal `(AVRational){1, AV_TIME_BASE}`. This syntax is non-standard in C++ and is strictly rejected by MSVC when `/std:c++17` is enabled.
**Solution:**
Replaced the `AV_TIME_BASE_Q` macro with FFmpeg's standard `av_make_q(1, AV_TIME_BASE)` function. This resolves the C4576 compiler error and ensures modern C++ compatibility.
*(Note: `av_make_q` is already smoothly polyfilled in `cap_ffmpeg_impl.hpp` for extremely old FFmpeg versions, making this a highly safe, consistent, and zero-overhead replacement.)*
### Pull Request Readiness Checklist
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Add CAP_PROP_IMAGE_SEQ_START #28844
Resolves https://github.com/opencv/opencv/issues/28843
New CAP_PROP_IMAGE_SEQ_START as an open only property for setting the first frame index when a VideoCap is opening with pattern, squashes test_images TODO.
`CAP_FFMPEG`: forwarded to the image2 demuxers "start_number" option.
`CAP_IMAGES`: Now a WithParams variant so the value reaches open() before probe runs, replaces 0 or 1 auto probe for sequence start.
Property is opt in so default behavior is not affected.
Please note that G_STREAMER is not considered here as I think its out of scope, it already has a "start-index" property and its backend is driven by the pipeline strings rather then these printf patterns.
If an alternative solution is preferred that will not involve a new property or promoting CAP_IMAGES to a "WithParams" variant I don't mind implementing.
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Bump some calib3d files to C++ #28825
This is just copy/pasting files from 5.x (first commit) and applying some light patch for compilation (second commit).
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Avoid lossy Latin-1 conversions when creating/looking up Qt HighGUI windows and convert C-string entry points to UTF-8 explicitly. This fixes non-ASCII title handling paths that could lead to mismatched window lookup and silent display failures.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
objdetect: clear stale outputs in CharucoDetector::detectDiamonds #28818
## Summary
- clear `diamondCorners`/`diamondIds` outputs at the beginning of `CharucoDetector::detectDiamonds`
- prevent stale detections from previous calls when the current call has fewer than 4 markers or finds no diamonds
- add a regression test that pre-fills outputs, calls `detectDiamonds` with 3 markers, and verifies outputs are empty
Fixes#28783.
## Testing
- built `opencv_test_objdetect` locally
- ran `opencv_test_objdetect --gtest_filter=Charuco.detectDiamondsClearsOutputsWithLessThanFourMarkers`
- result: PASS
Multiscale ECC #28802
OpenCV Extra: https://github.com/opencv/opencv_extra/pull/1338
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Previously, OpenCL in-place flip kernels (rows/cols/both) could produce
incorrect results compared to the CPU implementation on strict OpenCL
drivers such as Mesa. The kernels relied on implicit load–load–store–store
(LLSS) ordering when src and dst alias, which is not guaranteed by the
OpenCL memory model and may be reordered.
Some vendor drivers happened to preserve the expected ordering, masking
the issue, but Mesa correctly exposes the undefined behavior.
This change introduces dedicated in-place flip kernels that:
- Explicitly detect in-place execution (src == dst)
- Stage data through local memory tiles
- Enforce correct ordering with work-group barriers
- Avoid global memory read/write aliasing hazards
The non in-place path is unchanged.
With this fix, OpenCL in-place flip produces correct and consistent results
across drivers, matches CPU behavior, and complies with the OpenCL memory
model.
Signed-off-by: jiajia Qian <jiajia.qian@nxp.com>
Avfoundation fractional fps seek fix#28833
Accompanied by PR on [opencv_extra](https://github.com/opencv/opencv_extra/pull/1345)
Fixes https://github.com/opencv/opencv/issues/28831
AVFoundation backend seeking slowly drifts for any video which has a non-integer frame rate.
Narrowing of a float `mAssetTrack.nominalFrameRate` to int32_t means fractional rates are treated as integer when seeking by frame number.
Solution implemented in this branch is to use the tracks native rational frame duration when seeking (and available).
I've also included an AVF only test case which uses a new test file in opencv_extra. This test just compares the video caps expected ms vs actual for a known rate file (23.976).
Could consider extending this test to more then just AVF, as from what I can see there are no fractional rate tests / files.
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Alexander Smorkalov
Kumataro
Alexander Smorkalov
Vincent Rabaud
Alex Wu
Anand Mahesh
Maksim Shabunin
Samaresh Kumar Singh
Pierre Chatelier
Teddy-Yangjiale
ekharkov
Ismail
kirilllapi
Chevi koren
Michael Klatis
Alex
Mulham Fetna
Jeevan Mohan Pawar
kjg0724
4ekmah
jiajia Qian