**Merge with contrib**: https://github.com/opencv/opencv_contrib/pull/3003
### 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 other license that is incompatible with OpenCV
- [x] The PR is proposed to proper branch
- [ ] There is reference to 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
added blob contours to blob detector
* added blob contours
* Fixed Java regression test after new parameter addition to SimpleBlobDetector.
* Added stub implementation of SimpleBlobDetector::getBlobContours to presume source API compatibility.
This commit adds the feature of selecting the thickness
of the matches drawn by the drawMatches function.
In larger images, the default thickness of 1 pixel creates images
that are hard to visualize.
* 8-bit SIFT descriptors
* use clearer parameter
* update docs
* propagate type info
* overload function for avoiding ABI-break
* bugfix: some values are undefined when CV_SIMD is absent
* Implement ASIFT in C++
* '>>' should be '> >' within a nested template
* add a sample for asift usage
* bugfix empty keypoints cause crash
* simpler initialization for mask
* suppress the number of lines
* correct tex document
* type casting
* add descriptorsize for asift
* smaller testdata for asift
* more smaller test data
* add OpenCV short license header
* Get/Set functions for BRISK parameters, issue #11527.
Allows setting threshold and octaves parameters after creating a brisk object. These parameters do not affect the initial pattern initialization and can be changed later without re-initialization.
* Fix doc parameter name.
* Brisk get/set functions tests. Check for correct value and make tests independent of default parameter values.
* Add dummy implementations for BRISK get/set functions not to break API in case someone has overloaded the Feature2d::BRISK interface. This makes BRISK different from the other detectors/descriptors on the other hand, where get/set functions are pure virtual in the interface.
