COMPILE.md

How to compile the library

You can use the library.
Step:

• Complie it

mkdir build
cd build
cmake .. -DCMAKE_INSTALL_PREFIX=install -DBUILD_SHARED_LIBS=ON -DCMAKE_BUILD_TYPE=Release -DDEMO=OFF
cmake --build . --config Release
cmake --build . --config Release --target install

Dynamic libraries are generated. If you want to generate static libraries, you need to set the parameter: BUILD_SHARED_LIBS = OFF

• Use find_package(facedetection) in CMakeLists of your project

find_package(facedetection)
if(facedetection_FOUND)
    # your code
endif()

Example

• Examples of this project
  If you want to run the examples. you must be isntalled opencv library and set OpenCV_DIR first, then run the command:

mkdir build
cd build
cmake .. -DDEMO=ON -DOpenCV_DIR=
cmak --build . 

• Third-party examples

  • FaceRecognizer: https://github.com/KangLin/FaceRecognizer
    It's a cross-platforms programe. It's supported windows, linux, android etc.

Use Tengine to Speedup the detection on ARM

The model has been added to Tengine. Tengine, developed by OPEN AI LAB, is a lite, high-performance, and modular inference engine for embedded device.

The model in Tengine can run faster than the C++ source code here because Tengine has been optimized according to ARM CPU. There are detailed manual and example at Tengine web site: https://github.com/OAID/Tengine/tree/master/examples/YuFaceDetectNet

Cross build for aarch64

1. Set cross compiler for aarch64 (please refer to aarch64-toolchain.cmake)
2. Set opencv path since the example code depends on opencv

cmake \
    -DENABLE_NEON=ON \
    -DCMAKE_BUILD_TYPE=RELEASE \
    -DCMAKE_TOOLCHAIN_FILE=../aarch64-toolchain.cmake \
     ..

make

Native build for avx2

cmake \
    -DENABLE_AVX2=ON \
    -DCMAKE_BUILD_TYPE=RELEASE \
    -DDEMO=ON \
     ..

make

Android platform compilation instructions

• Install ndk

  • Download and install to /home/android-ndk from https://developer.android.com/ndk/downloads

  • Setting environment variables

    export ANDROID_NDK=/home/android-ndk
    

• Complie

  • The host is linux

    • Compile

        mkdir build
        cd build
        cmake .. -DCMAKE_INSTALL_PREFIX=install \
              -DCMAKE_BUILD_TYPE=MinSizeRel \
              -DCMAKE_TOOLCHAIN_FILE=${ANDROID_NDK}/build/cmake/android.toolchain.cmake \
              -DANDROID_ABI="arm64-v8a" \
              -DANDROID_PLATFORM=android-18 \
              -DUSE_OPENMP=OFF \
              -DENABLE_NEON=ON \
              -DENABLE_AVX2=OFF \
              -DDEMO=OFF
        cmake --build . --config MinSizeRel
      

    • Installation

        cmake --build . --config MinSizeRel --target install/strip
      

  • The host is windows

    • cmd

      • Compile

        mkdir build
        cd build
        cmake .. -DCMAKE_INSTALL_PREFIX=%cd%\install ^
              -G"Unix Makefiles" ^
              -DCMAKE_BUILD_TYPE=MinSizeRel ^
              -DCMAKE_TOOLCHAIN_FILE=%ANDROID_NDK%/build/cmake/android.toolchain.cmake ^
              -DCMAKE_MAKE_PROGRAM=%ANDROID_NDK%/prebuilt/windows-x86_64/bin/make.exe ^
              -DANDROID_ABI=arm64-v8a ^
              -DANDROID_ARM_NEON=ON ^
              -DANDROID_PLATFORM=android-24 ^
              -DUSE_OPENMP=OFF ^
              -DENABLE_NEON=ON ^
              -DENABLE_AVX2=OFF ^
              -DDEMO=OFF
        cmake --build . --config MinSizeRel
        

      • Installation

        cmake --build . --config MinSizeRel --target install/strip
        

    • msys2 or cygwin

      • Compile

        mkdir build
        cd build
        cmake .. -DCMAKE_INSTALL_PREFIX=install \
              -G"Unix Makefiles" \
              -DCMAKE_BUILD_TYPE=MinSizeRel \
              -DCMAKE_TOOLCHAIN_FILE=${ANDROID_NDK}/build/cmake/android.toolchain.cmake \
              -DCMAKE_MAKE_PROGRAM=${ANDROID_NDK}\prebuilt\windows-x86_64\bin\make.exe \
              -DANDROID_ABI=arm64-v8a \
              -DANDROID_ARM_NEON=ON \
              -DUSE_OPENMP=OFF \
              -DENABLE_NEON=ON \
              -DENABLE_AVX2=OFF \
              -DDEMO=OFF
        cmake --build . --config MinSizeRel
        

      • Installation

        cmake --build . --config MinSizeRel --target install/strip
        

  • Parameter Description: https://developer.android.google.cn/ndk/guides/cmake

    • ANDROID_ABI: The following values can be taken: Goal ABI. If the target ABI is not specified, CMake uses armeabi-v7a by default. Valid ABI are:
      • armeabi：CPU with software floating point arithmetic based on ARMv5TE
      • armeabi-v7a：ARMv7-based device with hardware FPU instructions (VFP v3 D16)
      • armeabi-v7a with NEON：Same as armeabi-v7a, but with NEON floating point instructions enabled. This is equivalent to setting -DANDROID_ABI=armeabi-v7a and -DANDROID_ARM_NEON=ON.
      • arm64-v8a：ARMv8 AArch64 Instruction Set
      • x86：IA-32 Instruction Set
      • x86_64 - x86-64 Instruction Set
    • ANDROID_NDK The path of installed ndk in host
    • ANDROID_PLATFORM: For a full list of platform names and corresponding Android system images, see the [Android NDK Native API] (https://developer.android.google.com/ndk/guides/stable_apis.html)
    • ANDROID_ARM_MODE
    • ANDROID_ARM_NEON
    • ANDROID_STL:Specifies the STL that CMake should use.
      • c++_shared: use libc++ shared library
      • c++_static: use libc++ static library
      • none: no stl
      • system: use system STL