samples: add color-coded bounding boxes for multi QR code detection #29281
Improves the existing qrcode.py sample by adding color-coded bounding boxes when multiple QR codes are detected simultaneously.
Previously all QR codes were drawn with the same green color, making it hard to distinguish between them visually.
This change adds a QR_COLORS palette so each detected QR code gets a unique color, improving visual clarity for multi-QR detection.
Co-authored-by: Ayush Gupta <gupta.ayushg@gmail.com>
Update ArUco doc #28824
See https://github.com/opencv/opencv/pull/28823
Update of the ArUco doc but targeted for OpenCV 4.
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Chromatic aberration correction #27491
Merge with https://github.com/opencv/opencv_extra/pull/1266
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Parent issue: https://github.com/opencv/opencv/issues/27206
Related PR: [#27490](https://github.com/opencv/opencv/pull/27490)
This PR adds chromatic aberration correction in C++ based on calibration data from the python app.
This code adds a function for chromatic aberration correction based on the calibration file (Mat correctChromaticAberration(InputArray image, const String& calibration_file)), and a class ChromaticAberrationCorrector which can be used to correct images of the same camera under the same settings (so for the same calibration data that is initialized in the beginning).
Also, basic functionality and performance tests are added.
Fix regex escape warning in _coverage.py by using raw string #2819
while i am running '_coverage.py' I noticed there is a syntax warning:"\." It is an invalid escape sequence
The regex was written as a normal string with '\.' which is not valid escape in string literals and give problems and error in a new python versions.
To fix this switch to raw string(r'cv2?\.\w+') which can passes the backslashes directly to the regex engine. This removes the warning and keeps the code and pattern working properly.
This is a small fix but important for future compatibilities.
Visualization script for one or more cameras calibration with calibration.cpp #27627
* It reads one or more YAML files produced by `calibration.cpp`.
* displays an interactive 3D scene of the calibration setup with camera frustums and board meshes.
* Supports both **camera-centric** and **board-centric** views.
* exports the entire scene as a `.obj/.mtl` for use in meshlab.
* also includes an error bar plot and frustum highlighting for single-camera setups.
calibration results generated by `calibration.cpp`: https://drive.google.com/drive/folders/13NvZHaxTFdAB-bzlNve8kKSMIg9gAu6K
Results Uploaded at: https://drive.google.com/drive/folders/1fkFyoBRGcNY4UCQhGgadO6uKlAkrzjTe
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2025-10-14T05:53:31.5387050Z C:\GHA-OCV-1\_work\ci-gha-workflow\ci-gha-workflow\opencv\modules\imgcodecs\src\bitstrm.cpp(156,57): warning C4244: 'argument': conversion from 'int64_t' to 'ptrdiff_t', possible loss of data [C:\GHA-OCV-1\_work\ci-gha-workflow\ci-gha-workflow\build\modules\imgcodecs\opencv_imgcodecs.vcxproj]
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Optional Known Foreground Mask for Background Subtractors #27810
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### Description
This adds an optional foreground input mask parameter to the MOG2 and KNN background subtractors, in line with issue https://github.com/opencv/opencv/issues/26476
4 tests are added under test_bgfg2.cpp:
2 for each subtractor type (1 with shadow detection and 1 without)
A demo shows the feature with only 3 parameters and with a 4th optional foreground mask for both core subtractor types.
Note: To patch contrib inheritance of the background subtraction class, empty apply method which throws a not implemented error is added to contrib subclasses. This is done to keep the overloaded apply function as pure virtual. Contrib PR to be made and linked shortly.
Contrib Repo Paired Pull Request: https://github.com/opencv/opencv_contrib/pull/4017
The Kullback-Leibler divergence works with histogram that have integral = 1,
otherwise it can return negative values. The normalization of the histograms
have been changed accordingly, and all the six comparison methods have been
used in the histogram comparison tutorial.
Adding color correction module to photo module from opencv_contrib #27051
This PR moved color correction module from opencv_contrib to main repo inside photo module.
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Fix NaNs in HDR Triangle Weights and Tonemapping and Update LDR Ground Truth in tutorial #27396
The PR closes#27392
Updated the triangle weights to use a small epsilon value instead of zero to prevent NaN issues in HDR processing.
Also fixed a float-to-double division issue by explicitly casting double values to float, which was previously producing garbage values and leading to NaNs in tonemapping.
The current LDR ground truth image used in the tutorial [ldr.png](https://github.com/opencv/opencv/blob/4.x/doc/tutorials/others/images/ldr.png) was originally generated using TonemapDurand (check this commit https://github.com/opencv/opencv/commit/833f8d16fab5e57c5e800a55fa0fb08c7a31c3b1), which was moved to opencv_contrib a long time ago in this commit: https://github.com/opencv/opencv/commit/742f22c09bd0c27b450f141bc984f280c8cde98e. However, the current Tonemap implementation in OpenCV main only performs normalization and gamma correction, which produces noticeably different results. This PR updates the LDR grouth truth image in tutorial with the result of TonemapDrago, and tutorials to use TonemapDrago as Tonemap gives a darker image.
Tonemap output:

TonemapDrago output:

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* Added mcc to opencv modules
* Removed color correction module
* Updated parameters return type
* Added python sample for macbeth_chart_detection
* Added models.yml support to samples
* Removed unnecessary headers and classes
* fixed datatype conversion
* fixed datatype conversion
* Cleaned headers and added reference/actual colors to samples
* Added mcc tutorial
* fixed datatype and header
* replaced unsigned with int
* Aligned actual and reference color function, added imread
* Fixed shadow variable
* Updated samples
* Added last frame colors prints
* updated detector class
* Added getter functions and useNet function
* Refactoring
* Fixes in test
* fixed infinite divison issue
Removal of deprecated functions in imgproc #26914
Fixes : #26410
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Animated WebP Support #25608
related issues #24855#22569
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Improved Tracker Samples #26202
Relates to #25006
This sample has been rewritten to track a selected target in a video or camera stream. It combines VIT tracker, Nano tracker and Dasiamrpn tracker into one tracker sample
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Features2d cleanup: Move several feature detectors and descriptors to opencv_contrib #25292
features2d cleanup: #24999
The PR moves KAZE, AKAZE, AgastFeatureDetector, BRISK and BOW to opencv_contrib/xfeatures2d.
Related PR: opencv/opencv_contrib#3709
Update Documentation #26260
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- Added function overload for the simple case
- Added CV_Bool type support for masks
- `parallel_for_` for intrinsics calibration for faster inference
- Homogenize parameters order with other calibrateXXX functions