openCV安装

2019-10-21

AS和cmake笔记

android的cpu架构

• android查看cpu架构(termux)

cat /proc/cpuinfo

• AArch32是ARMv7架构的一种执行状态
• AArch64是ARMv8架构的一种执行状态
  • 参考
  • 参考
• 64位ARMv8包含上面两种状态
  • 参考
  • 知乎
  • 知乎

cmake在AS中的使用

不要把mk和cmake两种方法混淆

输出控制(message)

(TODO)如果想直接看到打印信息,使用WARNING以上的级别进行打印

• message(WARNING "fuck")
  • 在Build->Build Output->CMake warnings查看
  • 在Build->Build Output->Toggle View查看

Android

Android Studio版本为3.5

OpenCV for Android 3.x:只使用java模块

参考:CSDN,示例:压缩图片

1. File->New->Import Module->选择opencv文件夹下的sdk/java文件夹,此时Android Studio会自动加载Module name
2. File->Project Structure->Dependencies->选择app->添加Module Dependency->选择opencv
3. 将opencv文件夹下的sdk/native/libs下自己手机cpu对应的架构文件夹复制到app/libs下
4. 将opencv模块的build.gradle的complieSdkVersion,buildToolVersion,minSdkVersion,targetSdkVersion改成和app的build.gradle一样
5. 在app的build.gradle的android节点下添加

   sourceSets { main { jni.srcDirs = [] jniLibs.srcDirs = ['libs'] } }

然后点击sync now

6. 在使用opencv前进行初始化

   static { if (!OpenCVLoader.initDebug()) { ... } }

常见问题

1. Caused by: CvException [org.opencv.core.CvException: OpenCV(4.1.1) /build/master_pack-android/opencv/modules/java/generator/src/cpp/utils.cpp:101: error: (-215:Assertion failed)

在Mat与Bitmap互转的时候长宽设置不对

OpenCV for Android 3.x:使用native模块

方法一

1. CMakeLists.txt编写

在CMakeLists.txt中确定两个关键路径

• /sdk/native/jni/include:头文件位置
• /sdk/native/libs/${ANDROID_ABI}/libopencv_java3.so:库位置

cmake_minimum_required(VERSION 3.4.1)

#1
set(opencv_version OpenCV4-android-sdk)
set(opencv_lib libopencv_java4.so)

#2
include_directories(/home/lynx/fuck_mount/Android/Proj/${opencv_version}/sdk/native/jni/include)
add_library(fuck SHARED IMPORTED)
  set_target_properties(fuck PROPERTIES IMPORTED_LOCATION
      /home/lynx/fuck_mount/Android/Proj/${opencv_version}/sdk/native/libs/${ANDROID_ABI}/${opencv_lib})


add_library(保持原样)

find_library(保持原样)

target_link_libraries(
        native-lib

        #3
        fuck

        ${log-lib})

2. 修改app的build.gradle

在android节点下插入

sourceSets {
  main {
    jniLibs.srcDirs = ['/home/lynx/fuck_mount/Android/Proj/OpenCV4-android-sdk/sdk/native/libs']
  }
}

方法二

参考:CSDN

还没有成功

1. CMakeLists.txt编写

在CMakeLists.txt中确定一个关键路径

• /sdk/native/jni/include:头文件位置

cmake_minimum_required(VERSION 3.4.1)

#1
set(opencv_version OpenCV4-android-sdk)
set(opencv_lib libopencv_java4.so)

#2
set(OpenCV_STATIC ON)
set(OpenCV_DIR /home/lynx/fuck_mount/Android/Proj/${opencv_version}/sdk/native/jni)
  find_package(OpenCV REQUIRED)
if (OpenCV_FOUND)
  message(WARNING "opencv libs: ${OpenCV_LIBS}")
else (OpenCV_FOUND)
  message(WARNING "opencv not found")
endif(OpenCV_FOUND)

add_library(保持原样)

find_library(保持原样)

target_link_libraries(
        native-lib

        ${log-lib}

        #3
        ${OpenCV_LIBS})

常见问题

1. java.lang.UnsatisfiedLinkError: dlopen failed: library "libopencv_java3.so" not found

这是由于忘记了上面的第2步.Android Studio默认的jni路径为app/src/main/jniLibs,除了在CMakeLists.txt中导入opencv的库以外还需要二选一

• 将对应版本opencv的库(libs/下一级的各个${ANDROID_ABI}文件夹)移动到jniLibs下
• 在build.gradle中修改默认jni路径(见上面第2步)

2. 各种undefined reference to *

如std::ios_base::Init::Init()等

未解决

3. undefined reference to `AndroidBitmap_getInfo'

各类AndroidBitmap的问题

在CMakeLists.txt增加

target_link_libraries(
        # TODO 解决 AndroidBitmap 报错
        jnigraphics)

参考:CSDN,这是一个很小的库,展示一个稳定的,基于C语言的接口,使本机代码安全地访问Java对象的像素缓冲区的位图

OpenCV for Android 4.x:使用native模块

方法一

同3.x版本的方法一

常见问题

1. java.lang.UnsatisfiedLinkError: dlopen failed: library "libc++_shared.so" not found

stackoverflow

(不确定的解决方法)在app的gradle中修改

externalNativeBuild {
  cmake {
    cppFlags ""
      arguments "-DANDROID_STL=c++_shared"
  }
}

不要使用gnustl_shared或gnustl_static,已经过时

2. java.lang.UnsatisfiedLinkError: dlopen failed: library "libopencv_java4.so" not found

解决方案同3.x版本

OpenCV for Android 4.x:使用java+native模块

参考:CSDN

1. 加载native模块

2. File->New->Import Module->选择opencv文件夹下的sdk/java文件夹,自己定义模块的名字

3. 修改模块的gradle文件

// 将原来的application改成library
apply plugin: 'com.android.library'

android {
  // 将版本信息改得和`app`的`build.gradle`一样
  compileSdkVersion 29
  buildToolsVersion "29.0.2"
  defaultConfig {
    // 删除applicationId
    minSdkVersion 15
    targetSdkVersion 29
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
  }
  // 不改动
  buildTypes {
    release {
      minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
    }
  }
}

4. (重复)修改app的gradle文件,加载native/lib模块

javacv(使用不完整OpenCV 4.1.0)

不同导入方法,import的class位置可能不同

opencv部分功能的初始化

github原文

Loader.load(opencv_java.class);// 不能直接放在class开头

使用远程导入

app的build.gradle示例(最外节点)

ext {
    versions = [
            'javacv': '1.4.4',
            'ffmpeg': '4.1',
            'opencv': '4.0.1'
    ]
}

dependencies {
    ...
    implementation(group: 'org.bytedeco', name: 'javacv-platform', version: versions.javacv) {
      exclude group: 'org.bytedeco.javacpp-presets'
    }
    implementation group: 'org.bytedeco.javacpp-presets', name: 'ffmpeg', version: "${versions.ffmpeg}-${versions.javacv}"
    implementation group: 'org.bytedeco.javacpp-presets', name: 'ffmpeg', version: "${versions.ffmpeg}-${versions.javacv}", classifier: 'android-arm'
    implementation group: 'org.bytedeco.javacpp-presets', name: 'ffmpeg', version: "${versions.ffmpeg}-${versions.javacv}", classifier: 'android-arm64'
    implementation group: 'org.bytedeco.javacpp-presets', name: 'opencv', version: "${versions.opencv}-${versions.javacv}"
    implementation group: 'org.bytedeco.javacpp-presets', name: 'opencv', version: "${versions.opencv}-${versions.javacv}", classifier: 'android-arm'
    implementation group: 'org.bytedeco.javacpp-presets', name: 'opencv', version: "${versions.opencv}-${versions.javacv}", classifier: 'android-arm64'
}

作为lib导入

根据手机具体的cpu架构进行导入

app的build.gradle

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
}

将文件(视具体情况)

• javacpp.jar
• javacv.jar
• openblas.jar
• openblas-android-arm64.jar
• opencv.jar
• opencv-android-arm64.jar
  复制到app/libs/文件夹里

常见错误

1. cpu架构错误/缺少(需添加-android-arm之类的库)

2019-10-27 16:01:32.439 29256-29322/? E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
    Process: com.github.crazyorr.ffmpegrecorder, PID: 29256
    java.lang.RuntimeException: An error occurred while executing doInBackground()

2. 没有对opencv初始化

2019-10-27 16:00:43.930 28933-28933/? E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.javacv, PID: 28933
    java.lang.UnsatisfiedLinkError: No implementation found for long org.opencv.core.Mat.n_Mat() (tried Java_org_opencv_core_Mat_n_1Mat and Java_org_opencv_core_Mat_n_1Mat__)

3. 缺少openblas的相关jar库

2019-10-27 15:59:23.158 28618-28618/? E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.javacv, PID: 28618
    java.lang.NoClassDefFoundError: Failed resolution of: Lorg/bytedeco/openblas/presets/openblas;

OpenCV 4.x source code

参考:CSDN

1. 修改参数

Android Studio的sdk下的ndk:ndk/build/cmake/android.toolchain.cmake(第112行)

elseif(ANDROID_TOOLCHAIN_NAME MATCHES "-[0-9].[0-9]$")
  set(ANDROID_TOOLCHAIN clang) # 将gcc改成clang
endif()

opencv 4.x源码:/platforms/android/build_sdk.py(第113行)

self.cmake_vars = dict(
    ANDROID_STL="c++_static", # change `gnustl_static` to `c++_static` or `c++_shared`
    ANDROID_ABI=self.name,
    ANDROID_PLATFORM_ID=platform_id,
)

opencv 4.x源码:/CMakeLists.txt(第426行和429行)(可以根据需要修改)

# OCV_OPTION(BUILD_SHARED_LIBS        "Build shared libraries (.dll/.so) instead of static ones (.lib/.a)" NOT (ANDROID OR APPLE_FRAMEWORK) )
OCV_OPTION(BUILD_SHARED_LIBS        "Build shared libraries (.dll/.so) instead of static ones (.lib/.a)" ON ) # 生成动态库
OCV_OPTION(BUILD_opencv_apps        "Build utility applications (used for example to train classifiers)" (NOT ANDROID AND NOT WINRT) IF (NOT APPLE_FRAMEWORK) )
OCV_OPTION(BUILD_opencv_js          "Build JavaScript bindings by Emscripten" OFF )
OCV_OPTION(BUILD_ANDROID_PROJECTS   "Build Android projects providing .apk files" OFF )
# OCV_OPTION(BUILD_ANDROID_PROJECTS   "Build Android projects providing .apk files" ON  IF ANDROID )

2. 配置JAVA_HOME

使用Android Studio的JDK位置

export JAVA_HOME=/home/lynx/fuck_mount/AS/jre

3. 执行platforms/android/build_sdk.py,完成编译

./build_sdk.py --ndk-path {ndk路径} --sdk_path {android sdk路径} {目标位置} {opencv源码位置}
# example
/home/lynx/fuck_mount/opencv_4_1_0/opencv-4.1.0/platforms/android/build_sdk.py --ndk_path /home/lynx/fuck_mount/Android/SDK/ndk/18.1.5063045 --sdk_path /home/lynx/fuck_mount/Android/SDK /home/lynx/fuck_mount/opencv_4_1_0/android_build /home/lynx/fuck_mount/opencv_4_1_0/opencv-4.1.0

• sdk-path:Android Studio的SDK目录
• ndk-path:Android Studio的SDK目录下ndk/{ndk版本号文件}

额外说明

不需要额外安装的软件:jdk,ninja-build,ndk.直接使用android studio的即可
不需要安装的软件:ant,ccache

目前还没能成功编译android project

能够混合使用:

• OpenCV 3.x的java库(配置见上)
• TODO

常见问题

1. java.lang.UnsatisfiedLinkError: dalvik.system.PathClassLoader[DexPathList[[zip file "/data/app/com.example.stitch-sPWgBONIqUrdX9XLB1OY6w==/base.apk"],nativeLibraryDirectories=[/data/app/com.example.stitch-sPWgBONIqUrdX9XLB1OY6w==/lib/arm64, /data/app/com.example.stitch-sPWgBONIqUrdX9XLB1OY6w==/base.apk!/lib/arm64-v8a, /system/lib64, /product/lib64]]] couldn't find "libnative-lib.so"

缺少相应ABI的so库(目前计时在gradle里加入abiFilters也没有用),上述报错是因为没有编译全ABI.ABI配置:opencv-4.x/platforms/android/ndk-18-api-level-21.config.py

Linux

OpenCV source code

目前适用4.x,其余没试过

依赖包

sudo apt install libgtk2.0-dev pkg-config

命令行安装(TODO)

1. cmake

cd {生成makefile的位置}
cmake {source的位置}

2. make

cd {生成makefile的位置}
make

3. make install

make install {安装的位置}

gui安装

参考:CSDN

1. 安装cmake-gui

sudo apt install cmake-gui

2. 启动cmake-gui

cd {build二进制文件的目录}
cmake-gui {opencv源代码}

3. Configure->Unix Makefiles:Use default native compilers->finish

4. 狂点Configure知道没有红色区域

5. 赋值

6. 狂点Configure

7. Generate,等到Generating done

8. 在源代码路径make

sudo make -j4 # 具体看有多少cpu
cat /proc/cpuinfo | grep "processor" | wc -l # 查看cpu个数
sudo make install

9. 配置opencv4.pc(2选1)

   • 修改PKG_CONFIG_PATH:增加{你cmake_install的路径}/lib/(opencv4.pc所在的文件夹路径)
   • (TODO,没试过)复制opencv4.pc到/usr/lib/pkgconfig

10. 配置库路径,(新建)/etc/ld.so.conf.d/opencv.conf

{你cmake_install路径}/lib/ # 自己的lib路径

sudo ldconfig

11. 编译测试

如果是opencv.pc将opencv4改成opencv

pkg-config --modversion opencv4
g++ a.cpp `pkg-config --cflags --libs opencv4` -o test && ./test

常见问题

1. 在其他项目中用CMake导入OpenCV模块:

   find_package(OpenCV REQUIRED) include_directories(${OpenCV_INCLUDE_DIRS})

之后cmake出现By not providing "FindOpenCV.cmake" in CMAKE_MODULE_PATH ...:

这是由于没有设置环境变量OpenCV_DIR,设置为OpenCV编译后的目录下含有OpenCVConfig.cmake的对应路径