OpenCV 4 about openbr

[dnandha]

I've ported the project to opencv4, you can check it out here
https://github.com/dnandha/openbr/tree/opencv4-port

It compiles nicely with OpenCV 4.1.0, some SegFaults with newer QT5 versions are also fixed. However, the fork is not downwards compatible to CV2/CV3, and the boost components (boost, adaboost, forest, etc.) need to be rewritten from ground up to work with OpenCV4; so that's a TODO which is marked in the code as such.

If any of the maintainers is interested, please create an appropriate branch here so I would open a PR to merge the port into the branch.

[jklontz]

Thank you for sharing this. We have in mind upgrading to OpenCV 4.x, but haven't made the time. We'll take a look at when we're ready to upgrade.

[canuysal]

@dnandha hey, I'm trying to build your port but it fails with the following error,
[ 2%] Building CXX object openbr/CMakeFiles/openbr.dir/plugins/imgproc/custom_sift.cpp.o
[ 2%] Linking CXX shared library libopenbr.so
/usr/bin/ld: cannot find -lopencv_contrib
/usr/bin/ld: cannot find -lopencv_nonfree
collect2: error: ld returned 1 exit status
openbr/CMakeFiles/openbr.dir/build.make:10388: recipe for target 'openbr/libopenbr.so.1.1.0' failed
make[2]: *** [openbr/libopenbr.so.1.1.0] Error 1
CMakeFiles/Makefile2:1021: recipe for target 'openbr/CMakeFiles/openbr.dir/all' failed
make[1]: *** [openbr/CMakeFiles/openbr.dir/all] Error 2
Makefile:162: recipe for target 'all' failed
make: *** [all] Error 2

How did you solve this? opencv 4.1.0 doesn't export libopencv_config and nonfree. Is something missing?

[y9luiz]

@canuysal you need to compile the opencv using the extra modules

you could find the extra module here: https://github.com/opencv/opencv_contrib

After download it please set the CMake variable at this way

cmake -DOPENCV_EXTRA_MODULES_PATH=<opencv_contrib>/modules <opencv_source_directory>

After that you may be able to use the openbr tool, have fun ^^