如何為Android平臺編譯 opencv3 和 opencv_contrib (Linux)
阿新 • • 發佈：2017-09-20
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本文以編譯opencv 3.3.0 和 opencv_contrib 3.3.0為例，系統為 Linux x64 (Fedora 21)，具體步驟如下：
1. 下載 Source code zip 壓縮包
從下面網址，選擇 opencv 3.3.0 Source code 下載
https://github.com/opencv/opencv/releases
從下面網址，選擇下載與
opencv
3.3.0 對應的
opencv_contrib
3.3.0
https://github.com/opencv/opencv_contrib/releases
註意：opencv和opencv_contrib
版本必須保持一致，否則可能會出現編譯錯誤。
2. 下載 build-opencv-for-android 開源代碼
$ cd /mnt/work
$ git clone https://github.com/tzutalin/build-opencv-for-android.git
$ cd build-opencv-for-android
3. 解壓源碼包並重命名
將opencv-3.3.0.zip 和 opencv_contrib-3.3.0.zip 都解壓到下載的build-opencv-for-android 開源代碼 所在目錄 /mnt/work/build-opencv-for-android 。
$ unzip opencv-3.3
4. 修改 build-opencv-for-android 開源代碼中 build-android-opencv.sh
修改內容如下：
修改 第 6 行代碼：
declare -a ANDROID_ABI_LIST=("x86" "x86_64" "armeabi" "arm64-v8a" "armeabi-v7a" "mips" "mips64")
為
declare -a ANDROID_ABI_LIST=("armeabi-v7a")
最終代碼，如下：
1 #!/bin/bash
2 NDK_ROOT="${1:-${NDK_ROOT}}"
3
4 ### ABIs setup
5 #declare -a ANDROID_ABI_LIST=("x86" "x86_64" "armeabi-v7a with NEON" "arm64-v8a")
6 declare -a ANDROID_ABI_LIST=("armeabi-v7a")
7
8 ### path setup
9 SCRIPT=$(readlink -f $0)
10 WD=`dirname $SCRIPT`
11 OPENCV_ROOT="${WD}/opencv"
12 N_JOBS=${N_JOBS:-4}
13
14 ### Download android-cmake
15 if [ ! -d "${WD}/android-cmake" ]; then
16 echo ‘Cloning android-cmake‘
17 git clone https://github.com/taka-no-me/android-cmake.git
18 fi
19
20 INSTALL_DIR="${WD}/android_opencv"
21 rm -rf "${INSTALL_DIR}/opencv"
22
23 ### Make each ABI target iteratly and sequentially
24 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 fi
34
35 temp_build_dir="${OPENCV_ROOT}/platforms/build_android_${ANDROID_ABI}"
36 ### Remove the build folder first, and create it
37 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="${INSTALL_DIR}/opencv" 54 ../..
55 # Build it
56 make -j${N_JOBS}
57 # Install it
58 make install/strip
59 ### Remove temp build folder
60 cd "${WD}"
61 rm -rf "${temp_build_dir}"
62 echo "end building ${ANDROID_ABI} version"
63 done
View Code
說明：
1). 由於目前 大多數 android 平臺使用arm cpu, 采用armeabi-v7 指令集，為了減少編譯時間，所有我只保留 "armeabi-v7a" ， 其他刪除，如果需要也可保留。
2). armeabi-v7 代表 arm EABI version 7 指令集, EABI 為 嵌入應用二進制接口 (Embedded Application Binary Interface) 。
5. 執行腳本 build-android-opencv.sh
$ ./build-android-opencv.sh /mnt/work/android/android-sdk-linux/ndk-bundle
註：build-android-opencv.sh腳本的通用的執行命令格式為“./build-android-opencv.sh [NDK_ROOT]”，其中，參數NDK_ROOT是可選的，表示Android Native Development Kit (NDK) 頂層目錄，如果沒有提供，則會試圖尋找環境變量 ANDROID_NDK。
6. 查看編譯結果
編譯成功後，會在 build-opencv-for-android 目錄，即build-android-opencv.sh腳本所在目錄，生成 android_opencv目錄，其目錄結構如下：
$ 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-v7a
62 directories
問題與解決方法
問題一
$ ./build-android-opencv.sh
Start 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 not find neither 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 NDK in the default path:
sudo ln -s ~/my-android-ndk /opt/android-ndk
sudo 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 not find 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 not find 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 to find the compiler by setting the CMake cache entry
CMAKE_CXX_COMPILER to the full path to the compiler, or to the compiler
name if it is in the PATH.
CMake Error at CMakeLists.txt:127 (project):
No CMAKE_C_COMPILER could be found.
Tell CMake where to find the compiler by setting the CMake cache entry
CMAKE_C_COMPILER to the full path to the compiler, or to the compiler name
if it is in the 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
解決方法
方法一（推薦方法）
從命令行傳入 NDK_ROOT 目錄，如下：
$ ./build-android-opencv.sh /mnt/work/android/android-sdk-linux/ndk-bundle/
方法二，
根據提示，設置環境變量 ANDROID_NDK，如下
$ export ANDROID_NDK=/mnt/work/android/android-sdk-linux/ndk-bundle/
$ env | grep ANDROID_NDK
ANDROID_NDK=/mnt/work/android/android-sdk-linux/ndk-bundle/
$ ./build-android-opencv.sh
參考資料
1. Build and install OpenCV and contrib lib on Ubuntu / Android 鏈接一 鏈接二（轉載）
2. 如何編譯 opencv3 和 opencv_contrib（Linux）
如何為Android平臺編譯 opencv3 和 opencv_contrib (Linux)