Agfdhyk

System information (version)

OpenCV => 3.4.4

Platform => ARM
(armeabiv7-a)

Android API Level => 24

Compiler => Clang 5.0

Android STL => gnustl_shared

NDK VERSION => NDK 15c

TOOLCHAIN USED => Opencv 3.4.4 toolchain android.

Goal of my request

Opti => NEON for Opencv (armeabiv7-a with NEON)

Introduction

My project, will use many things with Opencv, in Window we can't see a latency, however in Android we can see them.

After reading a lot of articles/forums/channels about Opencv with Android, I've seen that Opencv needed NEON on Android, ARM to do something well and without latency and run with optimizations

Configure / Make Shared Lib

So, to date, I have downloaded sources of opencv 3.4.4 from the official website, I have run it into my CMAKE-GUI, I've made a lot of correction to make a build successfully, but I would note that I haven't disable the essential modules from opencv like (core or any others).

(If it's necessary I can host my output of cmake here.)

Then after configure and make it, I have my shared library which will be linked into my Android studio project with cmakelists and other things..

After sync correct, I have made my project.

Errors occurred with Android Studio compile the project

So, I have encountered a few undefined symbols with opencv only.

We can see them :

   error: undefined reference to 'cv::read(cv::FileNode const&, std::__ndk1::vector<cv::KeyPoint, std::__ndk1::allocator<cv::KeyPoint> >&)'

  error: undefined reference to 'cv::write(cv::FileStorage&, cv::String const&, std::__ndk1::vector<cv::KeyPoint, std::__ndk1::allocator<cv::KeyPoint> > const&)'

  error: undefined reference to 'cv::KeyPointsFilter::retainBest(std::__ndk1::vector<cv::KeyPoint, std::__ndk1::allocator<cv::KeyPoint> >&, int)'

  error: undefined reference to 'cv::read(cv::FileNode const&, std::__ndk1::basic_string<char, std::__ndk1::char_traits<char>, std::__ndk1::allocator<char> >&, std::__ndk1::basic_string<char, std::__ndk1::char_traits<char>, std::__ndk1::allocator<char> > const&)'

  error: undefined reference to 'cv::KeyPointsFilter::retainBest(std::__ndk1::vector<cv::KeyPoint, std::__ndk1::allocator<cv::KeyPoint> >&, int)'

  error: undefined reference to 'cv::KeyPointsFilter::retainBest(std::__ndk1::vector<cv::KeyPoint, std::__ndk1::allocator<cv::KeyPoint> >&, int)'

  error: undefined reference to 'cv::DescriptorMatcher::knnMatch(cv::_InputArray const&, cv::_InputArray const&, std::__ndk1::vector<std::__ndk1::vector<cv::DMatch, std::__ndk1::allocator<cv::DMatch> >, std::__ndk1::allocator<std::__ndk1::vector<cv::DMatch, std::__ndk1::allocator<cv::DMatch> > > >&, int, cv::_InputArray const&, bool) const'

  error: undefined reference to 'cv::DescriptorMatcher::knnMatch(cv::_InputArray const&, cv::_InputArray const&, std::__ndk1::vector<std::__ndk1::vector<cv::DMatch, std::__ndk1::allocator<cv::DMatch> >, std::__ndk1::allocator<std::__ndk1::vector<cv::DMatch, std::__ndk1::allocator<cv::DMatch> > > >&, int, cv::_InputArray const&, bool) const'

  error: undefined reference to 'cv::KeyPointsFilter::retainBest(std::__ndk1::vector<cv::KeyPoint, std::__ndk1::allocator<cv::KeyPoint> >&, int)'

  error: undefined reference to 'cv::DescriptorMatcher::knnMatch(cv::_InputArray const&, cv::_InputArray const&, std::__ndk1::vector<std::__ndk1::vector<cv::DMatch, std::__ndk1::allocator<cv::DMatch> >, std::__ndk1::allocator<std::__ndk1::vector<cv::DMatch, std::__ndk1::allocator<cv::DMatch> > > >&, int, cv::_InputArray const&, bool) const'

  error: undefined reference to 'cv::DescriptorMatcher::knnMatch(cv::_InputArray const&, cv::_InputArray const&, std::__ndk1::vector<std::__ndk1::vector<cv::DMatch, std::__ndk1::allocator<cv::DMatch> >, std::__ndk1::allocator<std::__ndk1::vector<cv::DMatch, std::__ndk1::allocator<cv::DMatch> > > >&, int, cv::_InputArray const&, bool) const'

  error: undefined reference to 'cv::drawKeypoints(cv::_InputArray const&, std::__ndk1::vector<cv::KeyPoint, std::__ndk1::allocator<cv::KeyPoint> > const&, cv::_InputOutputArray const&, cv::Scalar_<double> const&, int)'

  clang++: error: linker command failed with exit code 1 (use -v to see invocation)

  ninja: build stopped: subcommand failed.

I don't know what are she's doing, but I want these optimizations and I will be very grateful if you have some things to tell me.

Best Regards !!