为android平台编译opencv,如何为Android平台编译 opencv3 和 opencv_contrib (Linux)(示例代码)...

本文以编译opencv3.3.0和opencv_contrib 3.3.0为例，系统为Linux x64 (Fedora 21)，具体步骤如下：

1. 下载Source code zip 压缩包

从下面网址，选择opencv 3.3.0 Source code下载https://github.com/opencv/opencv/releases

从下面网址，选择下载与opencv

3.3.0对应的opencv_contrib

3.3.0

https://github.com/opencv/opencv_contrib/releases

注意：opencv和opencv_contrib版本必须保持一致，否则可能会出现编译错误。

2.下载build-opencv-for-android开源代码

$ cd /mnt/work

$ git clone https://github.com/tzutalin/build-opencv-for-android.git

$ cd build-opencv-for-android

3.解压源码包并重命名

将opencv-3.3.0.zip和opencv_contrib-3.3.0.zip都解压到下载的build-opencv-for-android开源代码 所在目录/mnt/work/build-opencv-for-android。

$ unzip opencv-3.3.0.zip -d /mnt/work/build-opencv-for-android

$unzip opencv_contrib-3.3.0.zip -d /mnt/work/build-opencv-for-android

$ cd/mnt/work/build-opencv-for-android

$mv opencv-3.3.0opencv

$mv opencv_contrib-3.3.0 opencv_contrib

4. 修改build-opencv-for-android开源代码中build-android-opencv.sh

修改内容如下：

修改 第6行代码：

declare -a ANDROID_ABI_LIST=("x86" "x86_64" "armeabi" "arm64-v8a" "armeabi-v7a" "mips" "mips64")

为

declare -a ANDROID_ABI_LIST=("armeabi-v7a")

最终代码，如下：

1 #!/bin/bash2 NDK_ROOT="${1:-${NDK_ROOT}}"

3

4 ###ABIs setup5 #declare -a ANDROID_ABI_LIST=("x86" "x86_64" "armeabi-v7a with NEON" "arm64-v8a")

6 declare -a ANDROID_ABI_LIST=("armeabi-v7a")

7

8 ### pathsetup9 SCRIPT=$(readlink -f $0)

10 WD=`dirname $SCRIPT`11 OPENCV_ROOT="${WD}/opencv"

12 N_JOBS=${N_JOBS:-4}13

14 ###Download android-cmake15 if [ ! -d "${WD}/android-cmake" ]; then

16 echo‘Cloning android-cmake‘17 git clone https://github.com/taka-no-me/android-cmake.git18 fi19

20 INSTALL_DIR="${WD}/android_opencv"

21 rm -rf "${INSTALL_DIR}/opencv"

22

23 ###Make each ABI target iteratly and sequentially24 for i in "${ANDROID_ABI_LIST[@]}"

25 do

26 ANDROID_ABI="${i}"

27 echo "Start building ${ANDROID_ABI} version"

28

29 if [ "${ANDROID_ABI}" = "armeabi" ]; then

30 API_LEVEL=19

31 else

32 API_LEVEL=21

33 fi34

35 temp_build_dir="${OPENCV_ROOT}/platforms/build_android_${ANDROID_ABI}"

36 ### Remove the build folder first,and create it37 rm -rf "${temp_build_dir}"

38 mkdir -p "${temp_build_dir}"

39 cd "${temp_build_dir}"

40

41 cmake -DCMAKE_BUILD_WITH_INSTALL_RPATH=ON 42 -DCMAKE_TOOLCHAIN_FILE="${WD}/android-cmake/android.toolchain.cmake" 43 -DANDROID_NDK="${NDK_ROOT}" 44 -DANDROID_NATIVE_API_LEVEL=${API_LEVEL} 45 -DANDROID_ABI="${ANDROID_ABI}" 46 -D WITH_CUDA=OFF 47 -D WITH_MATLAB=OFF 48 -D BUILD_ANDROID_EXAMPLES=OFF 49 -D BUILD_DOCS=OFF 50 -D BUILD_PERF_TESTS=OFF 51 -D BUILD_TESTS=OFF 52 -DOPENCV_EXTRA_MODULES_PATH="${WD}/opencv_contrib/modules/" 53 -DCMAKE_INSTALL_PREFIX="${INSTALL_DIR}/opencv" 54 ../..

55 #Build it56 make -j${N_JOBS}57 #Install it58 make install/strip59 ###Remove temp build folder60 cd "${WD}"

61 rm -rf "${temp_build_dir}"

62 echo "end building ${ANDROID_ABI} version"

63 done

View Code

说明：

1).由于目前 大多数android平台使用arm cpu,采用armeabi-v7指令集，为了减少编译时间，所有我只保留"armeabi-v7a"， 其他删除，如果需要也可保留。2). armeabi-v7代表arm EABI version 7指令集, EABI为 嵌入应用二进制接口(Embedded Application Binary Interface)。

5.执行脚本build-android-opencv.sh

$ ./build-android-opencv.sh /mnt/work/android/android-sdk-linux/ndk-bundle

注：build-android-opencv.sh脚本的通用的执行命令格式为“./build-android-opencv.sh [NDK_ROOT]”，其中，参数NDK_ROOT是可选的，表示Android Native Development Kit (NDK)顶层目录，如果没有提供，则会试图寻找环境变量ANDROID_NDK。

6. 查看编译结果

编译成功后，会在build-opencv-for-android目录，即build-android-opencv.sh脚本所在目录，生成android_opencv目录，其目录结构如下：

$ tree -d android_opencv

android_opencv

└── opencv

├── apk

└── sdk

├── etc

│ ├── haarcascades

│ └── lbpcascades

└── native

├── 3rdparty

│ └── libs

│ └── armeabi-v7a

├── jni

│ ├── abi-armeabi-v7a

│ └── include

│ ├── opencv

│ └── opencv2

│ ├── aruco

│ ├── bioinspired

│ ├── calib3d

│ ├── ccalib

│ ├── core

│ │ ├── cuda

│ │ │ └── detail

│ │ ├── hal

│ │ └── utils

│ ├── datasets

│ ├── dnn

│ ├── face

│ ├── features2d

│ ├── flann

│ ├── fuzzy

│ ├── highgui

│ ├── imgcodecs

│ ├── img_hash

│ ├── imgproc

│ │ ├── detail

│ │ └── hal

│ ├── line_descriptor

│ ├── ml

│ ├── objdetect

│ ├── optflow

│ ├── phase_unwrapping

│ ├── photo

│ ├── reg

│ ├── rgbd

│ ├── saliency

│ ├── shape

│ ├── stereo

│ ├── stitching

│ │ └── detail

│ ├── structured_light

│ ├── superres

│ ├── surface_matching

│ ├── text

│ ├── tracking

│ ├── video

│ ├── videoio

│ ├── videostab

│ ├── xfeatures2d

│ ├── ximgproc

│ └── xphoto

└── libs

└── armeabi-v7a62 directories

问题与解决方法

问题一

$ ./build-android-opencv.shStart building armeabi-v7a version

CMake Error at/mnt/work/video/res/opencv/build-opencv-for-android-master/android-cmake/android.toolchain.cmake:446(message):

Could notfindneither Android NDK nor Android standalone toolchain.

You should either set an environment variable:

export ANDROID_NDK=~/my-android-ndk

or

export ANDROID_STANDALONE_TOOLCHAIN=~/my-android-toolchain

or put the toolchain or NDKinthe default path:sudo ln -s ~/my-android-ndk /opt/android-ndksudo ln -s ~/my-android-toolchain /opt/android-toolchain

Call Stack (most recent call first):/usr/share/cmake/Modules/CMakeDetermineSystem.cmake:98(include)

CMakeLists.txt:127(project)

CMake Error: Error required internal CMake variable not set, cmake may be not be built correctly.

Missing variable is:

CMAKE_CXX_COMPILER_ENV_VAR

CMake Error: Error required internal CMake variable not set, cmake may be not be built correctly.

Missing variable is:

CMAKE_CXX_COMPILER

CMake Error: Could notfind cmake module file: /mnt/work/video/res/opencv/build-opencv-for-android-master/opencv/platforms/build_android_armeabi-v7a/CMakeFiles/3.0.2/CMakeCXXCompiler.cmake

CMake Error: Error required internal CMake variable not set, cmake may be not be built correctly.

Missing variable is:

CMAKE_C_COMPILER_ENV_VAR

CMake Error: Error required internal CMake variable not set, cmake may be not be built correctly.

Missing variable is:

CMAKE_C_COMPILER

CMake Error: Could notfind cmake module file: /mnt/work/video/res/opencv/build-opencv-for-android-master/opencv/platforms/build_android_armeabi-v7a/CMakeFiles/3.0.2/CMakeCCompiler.cmake

CMake Error at CMakeLists.txt:127(project):

No CMAKE_CXX_COMPILER could be found.

Tell CMake where tofindthe compiler by setting the CMake cache entry

CMAKE_CXX_COMPILER to the full path to the compiler, or to the compiler

nameif it is inthe PATH.

CMake Error at CMakeLists.txt:127(project):

No CMAKE_C_COMPILER could be found.

Tell CMake where tofindthe compiler by setting the CMake cache entry

CMAKE_C_COMPILER to the full path to the compiler, or to the compiler nameif it is inthe PATH.

CMake Error: CMAKE_CXX_COMPILER not set, after EnableLanguage

CMake Error: CMAKE_C_COMPILER not set, after EnableLanguage-- Configuring incomplete, errors occurred!

make: ***No targets specified and no makefile found. Stop.make: *** No rule to make target ‘install/strip‘. Stop.

end building armeabi-v7a version

解决方法

方法一(推荐方法)

从命令行传入NDK_ROOT 目录，如下：

$ ./build-android-opencv.sh /mnt/work/android/android-sdk-linux/ndk-bundle/

方法二，

根据提示，设置环境变量 ANDROID_NDK，如下

$ export ANDROID_NDK=/mnt/work/android/android-sdk-linux/ndk-bundle/$env | grepANDROID_NDK

ANDROID_NDK=/mnt/work/android/android-sdk-linux/ndk-bundle/$ ./build-android-opencv.sh

参考资料

1. Build and install OpenCV and contrib lib on Ubuntu / Android    链接一  链接二(转载)