System information (version)

• OpenCV 4.5.1
• Windows 64 Bit
• Python 3.9

Detailed description

There is a bug in the Tutorial code here under Stitching detailed (python opencv >4.0.1) respectively here in the Repo.

The Images to the Tutorial can be found here

Steps to reproduce

python stitching_detailed.py newspaper1.jpg newspaper2.jpg –work_megapix 0.6 –features surf –matcher affine –estimator affine –match_conf 0.3 –conf_thresh 0.3 –ba affine –ba_refine_mask xxxxx –wave_correct no –warp affine

without having installed opencv_contrib nonfree packages (especially SURF)

This will call an error: OpenCV(4.5.1) ..\opencv_contrib\modules\xfeatures2d\src\surf.cpp:1029: error: (-213:The function/feature is not implemented) This algorithm is patented and is excluded in this configuration; Set OPENCV_ENABLE_NONFREE CMake option and rebuild the library in function 'cv::xfeatures2d::SURF::create' even though the Script it's expected to warn the User and exit if SURF is not installed (the Option surf should not even be suggested as a kwarg)

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues,
  forum.opencv.org, Stack Overflow, etc and have not found solution
• I updated to latest OpenCV version and the issue is still there
• There is reproducer code and related data files: videos, images, onnx, etc